Papers - SUZUKI Yoshihiro
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Genetic diversity of dissolved free extracellular DNA compared to intracellular DNA in wastewater treatment plants Reviewed
Tamai, Soichiro Okuno, Miki Ogura, Yoshitoshi Suzuki, Yoshihiro
Science of The Total Environment 970 178989 2025.3
Authorship：Corresponding author Language：English Publishing type：Research paper (scientific journal)
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Detection and collection of shiga toxin-producing Escherichia coli using foam concentration without membrane filtration Reviewed
Tamai, S. Katafuchi, M. Hui, X. Suzuki, Y.
Ecotoxicology and Environmental Safety 2025.3
Authorship：Corresponding author Language：English Publishing type：Research paper (scientific journal)
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Optimizing the processing conditions of ballasted flocculation of actual turbid river water Reviewed
Suzuki, Yoshihiro Takahashi, Katsuya Kanai, Miyuka Tamai, Soichiro Annaka, Yuko Chuganji, Nobuaki
Urban Water Journal 22 ( 2 ) 236 - 243 2025.1
Authorship：Lead author, Corresponding author Language：English Publishing type：Research paper (scientific journal)
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Crop contamination evaluation by antimicrobial-resistant bacteria via livestock waste compost-fertilized field soil Reviewed
Suzuki, Yoshihiro Horita, Tomoyuki Nishimura, Emi Xie, Hui Tamai, Soichiro Kobayashi, Ikuo Fukuda, Akira Usui, Masaru
Journal of Hazardous Materials 480 135987 2024.9
Authorship：Lead author, Corresponding author Language：English Publishing type：Research paper (scientific journal)
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Year-round monitoring of antibiotic-resistant bacteria in pristine uppermost stream and estimation of pollution sources Reviewed
Nishimura, Emi Xie, Hui Tamai, Soichiro Nishiyama, Masateru Nukazawa, Kei Hoshiko, Yuki Ogura, Yoshitoshi Suzuki, Yoshihiro
Frontiers in Environmental Science 12 1439174 2024.9
Authorship：Corresponding author Language：English Publishing type：Research paper (scientific journal)
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Shwe Sin P.P., Wai S.H., Ota Y., Nishioka K., Suzuki Y.
International Journal of Hydrogen Energy 53 86 - 92 2024.1
Publishing type：Research paper (scientific journal) Publisher：International Journal of Hydrogen Energy
Hydrogen production from renewable electricity offers an eco-friendly alternative to fossil fuels. Proton exchange membrane (PEM) electrolysis is a well-known method for this purpose. Studies have primarily focused on reducing costs of noble catalysts, improving efficiency, managing system degradation, and addressing membrane thinning caused by contaminated cations. However, techniques for PEM recovery post-degradation are still under development. This study investigated the effects of cations on PEM cells using artificial soft water, and analyzed two recovery methods to restore cell performance. Our findings indicate a significant rise in cell operating voltage and a decrease hydrogen production over 8 h of operation with soft water. After introducing both recovery methods, the initial operating value was reinstated in both cases. Only nitric acid treatment, however, achieved hydrogen production levels comparable to those of ultrapure water.
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Mineda H., Nukazawa K., Suzuki Y.
Journal of Water and Climate Change 14 ( 12 ) 4821 - 4836 2023.12
Publishing type：Research paper (scientific journal) Publisher：Journal of Water and Climate Change
Hydrological alterations by dams and climate change can reduce aquatic biodiversity by disrupting the life cycles of organisms. Here, we aimed to evaluate and compare the hydrological alterations caused by dams and climate change throughout the Omaru River catchment, Japan, using a distributed hydrological model (DHM). First, to assess the impacts of dam and climate change independently, we performed runoff analyses using either dam discharge or future climatic data (two future periods, 2031–2050 and 2081–2100 x three representative con-centration pathways). Subsequently, we derived indicators of hydrologic alterations (IHA) to quantify changes in flow alterations by comparing them to IHA under natural conditions (i.e., without dam or climate change data). We found that dams altered IHAs more than climate change. However, on a catchment-scale standpoint, climate change induced wider ranges of flow alterations, such as a further decrease in low flow metrics along the tributaries and uppermost main stem, suggesting a catchment-level shrinkage in important corridors of aquatic organisms. We also observed that the altered flow by water withdrawals was ameliorated by the confluence of tributaries and downstream hydropower outflows. Our approach using a DHM captured the various patterns of flow alterations by dams and climate change.
DOI： 10.2166/wcc.2023.538
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Tamai S., Suzuki Y.
Microorganisms 11 ( 12 ) 2023.12
Publishing type：Research paper (scientific journal) Publisher：Microorganisms
Enterococcus spp. are common bacteria present in the intestinal tracts of animals and are used as fecal indicators in aquatic environments. On the other hand, enterococci are also known as opportunistic pathogens. Elucidating their composition in the intestinal tracts of domestic animals can assist in estimating the sources of fecal contamination in aquatic environments. However, information on the species and composition of enterococci in animal hosts (except humans) is still lacking. In this study, enterococci were isolated from the feces of cattle, pigs, birds, and humans using selective media. Enterococcal species were identified using mass spectrometry technology, and each host was characterized by diversity and cluster analysis. The most dominant species were E. hirae in cattle, E. faecium in birds, and E. faecalis in pigs and humans. Cattle had the highest alpha diversity, with high interindividual and livestock farm diversity. The dominant enterococcal species in pigs and humans were identical, and cluster analysis showed that the majority of the two hosts’ species clustered together.
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Optimum conditions for high-speed solid–liquid separation by ballasted flocculation Reviewed
Suzuki Y., Kaku R., Takahashi K., Kanai M., Tamai S., Annaka Y., Chuganji N.
Water Science and Technology 88 ( 1 ) 35 - 46 2023.7
Publishing type：Research paper (scientific journal) Publisher：Water Science and Technology
In the ballasted flocculation, high-speed sedimentation of suspensions is achieved using a microsand as a ballast material and a polymer flocculant combined with microflocs made of polyaluminum chloride (PAC) as an inorganic coagulant. In this study, three turbid water samples containing kaolin clay (kaolin concentration: 20, 200, and 500 mg/L) were treated by coagulation–sedimentation and ballasted flocculation. The effects of pH and PAC dosage, which are the controlling parameters for coagulation, and the microsand (silica sand) and polymer dosages, which are the controlling parameters for ballasted treatment, on the treatment efficiency and floc settling velocity were examined. The floc settling velocity under the optimum conditions was 17 times higher than that of the conventional coagulation–sedimentation process using PAC. The turbidity was 0.54 turbidity unit (TU) (TU as the kaolin standard), and its removal efficiency was 99.7%. Furthermore, turbid water samples with different kaolin concentrations (20 and 500 mg/L) were treated via the ballasted flocculation. In this study, fundamental information on the optimization of each dosage condition of coagulant, ballast, and polymer and pH condition in ballasted flocculation was obtained, and the removal mechanisms under optimal, underoptimistic and overoptimistic conditions were proposed.
DOI： 10.2166/wst.2023.204
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Xie H., Yamada K., Tamai S., Shimamoto H., Nukazawa K., Suzuki Y.
Environmental Science and Pollution Research 2023.6
Publishing type：Research paper (scientific journal) Publisher：Environmental Science and Pollution Research
Antibiotic-resistant bacteria (ARBs) can now be detected not only in clinical institutions but also in wastewater treatment plants (WWTPs), extending the range of emergence to residential areas. In this study, we investigated the change of antibiotic-resistant Escherichia coli (E. coli) and other coliforms in each treatment process at WWTPs. Throughout the treatment process, the numbers of E. coli and other coliforms were significantly reduced to less than 5.7 ± 0.5 CFU/100 ml and 2.4 ± 0.0×102 CFU/100 ml, respectively. However, ESBL-producing E. coli and other coliforms were detected in each treatment process (even after chlorination) at 5.6% and 4.8%, compared to the total E. coli and other coliforms counts. Then, ESBL-producing-related genes were identified via PCR analyses, and the most predominant gene was CTX-M-9 in both E. coli (47.2%) and other coliforms (47.3%). Although actual WWTPs greatly reduced the number of bacteria, the relative prevalence of ESBL-producing bacteria was increased, suggesting that ESBL-producing bacteria remain in the effluent at minimal concentrations and could be diffusing to water bodies.
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Tamai S., Ogura Y., Okuno M., Nukazawa K., Suzuki Y.
Environmental Science: Water Research and Technology 9 ( 7 ) 1792 - 1803 2023.4
Publishing type：Research paper (scientific journal) Publisher：Environmental Science: Water Research and Technology
Dissolved free extracellular DNA (exDNA), DNA released outside the cell, is present in aquatic environments at very low concentrations. Additionally, exDNA passes through a 0.22 μm filter, making it difficult to capture for analysis. Thus, information on exDNA is scarce, and the composition of genes present in exDNA is unknown. In this study, we developed a process for highly concentrating exDNA adsorbed on colloids and then dissolving the colloids with an acid using colloidal adsorption and foam concentration. After applying this strategy, 66.3% ± 3.3% of the uidA gene and 39.4% ± 2.4% of the tetA gene were recovered from genomic DNA carrying the uidA gene and plasmids carrying the tetA gene (n = 3), respectively. Using the developed method, 1000 mL of effluent of a wastewater treatment plant was concentrated to 400 μL, and exDNA was rapidly recovered at a high concentration (concentration ratio: 2500×). Furthermore, metagenomic analysis revealed the function of some exDNA genes, such as those encoding antibiotic resistance proteins. The information revealed in this study contributes to the elucidation of the mechanisms of horizontal gene transfer in aquatic environments.
DOI： 10.1039/d3ew00015j
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Tamai S., Shimamoto H., Nukazawa K., Suzuki Y.
Microorganisms 11 ( 4 ) 2023.4
Publishing type：Research paper (scientific journal) Publisher：Microorganisms
High counts of bacteria are present in beach sand, and human health threats attributable to contact with sand have been reported. In this study, we investigated fecal indicator bacteria in the top surface sand of coastal beaches. Monitoring investigations were performed during a monsoon when rainfall occurs randomly, and the composition of the coliforms was analyzed. The coliform count in the top surface sand (depth < 1 cm) increased by approximately 100 fold (26–2.23 × 103 CFU/100 g) with increasing water content because of precipitation. The composition of the coliforms in the top surface sand changed within 24 h of rainfall, with Enterobacter comprising more than 40% of the coliforms. Estimation of factors that changed the bacterial counts and composition revealed that coliform counts tended to increase with increasing water content in the top surface sand. However, the abundance of Enterobacter was independent of the sand surface temperature and water content. Coliform counts in the top surface sand rapidly increased and the composition showed remarkable variations because of the supply of water to the beach following rainfall. Among them, some bacteria with suspected pathogenicity were present. Controlling bacteria in coastal beaches is important for improving public health for beachgoers.
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Yadai T., Suzuki Y.
npj Clean Water 7 2023.2
Authorship：Corresponding author Language：English Publishing type：Research paper (scientific journal) Publisher：npj Clean Water
Efficient desalination through a reverse osmosis (RO) membrane requires the prior removal of blockade-causing substances from raw seawater. To achieve ultrahigh-speed processing of a pretreatment process for seawater RO desalination, we combine traditional softening with ballasted flocculation (SBF) for Ca2+ and Mg2+ removal. An alkaline mixture of Ca(OH)2 and Na2CO3 was the most suitable softening agent for Ca2+ and Mg2+ removal with a reduced amount of generated sludge. This softening treatment simultaneously removed the suspended solids and bacteria from actual seawater. The settling velocity of the suspended solids generated via seawater softening was extremely low. Under the optimum conditions for desalinating actual seawater using an anionic polymer flocculant and microsand, the settling velocity exceeded 3.5 cm/s, 833 times higher than that of softening without ballasted flocculation. The amount of sludge after standing for 3 min was 76.5% lower in SBF than in conventional softening. The silt density index of the treated seawater met the water-supply standard of RO membranes (i.e., <3.0). Furthermore, the SBF-generated sludge exhibited considerably improved dewatering property than the sludge obtained via conventional softening. SBF can efficiently and quickly remove the causative substances of RO membrane fouling from seawater, thereby improving the treatability of generated sludge. SBF provides a new pretreatment process for seawater desalination using RO membranes.
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Suzuki Y., Shimizu H., Tamai S., Hoshiko Y., Maeda T., Nukazawa K., Iguchi A., Masago Y., Ishii S.
Environmental Monitoring and Assessment 195 ( 2 ) 2023.2
Authorship：Lead author, Corresponding author Language：English Publishing type：Research paper (scientific journal) Publisher：Environmental Monitoring and Assessment
Waterborne diseases due to pathogen contamination in water are a serious problem all over the world. Accurate and simultaneous detection of pathogens in water is important to protect public health. In this study, we developed a method to simultaneously detect various pathogenic Escherichia coli by sequencing the amplicons of multiplex PCR. Our newly designed multiplex PCR amplified five genes for pathogenic E. coli (uidA, stx1, stx2, STh gene, and LT gene). Additional two PCR assays (for aggR and eae) were also designed and included in the amplicon sequencing analysis. The same assays were also used for digital PCR (dPCR). Strong positive correlations were observed between the sequence read count and the dPCR results for most of the genes targeted, suggesting that our multiplex PCR-amplicon sequencing approach could provide quantitative information. The method was also successfully applied to monitor the level of pathogenic E. coli in river water and wastewater samples. The approach shown here could be expanded by targeting genes for other pathogens.
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Ito K., Matsunaga M., Itakiyo T., Oishi H., Nukazawa K., Irie M., Suzuki Y.
International Journal of Sediment Research 2022.12
Authorship：Last author Language：English Publishing type：Research paper (scientific journal) Publisher：International Journal of Sediment Research
Sediment causes a serious problem in relation to dam function. A cooperative sediment sluicing operation has been under way since 2017 to prevent sediment from accumulating in dams in the Mimi River, Miyazaki, Japan. To achieve a smooth and stable operation, it is very important to determine the sediment source and a sediment transport system to maintain the dam's function. In the current study, the source and transport of sediment from the Mimi River basin have been analyzed with X-ray diffraction (XRD) to reveal the peaks of mineral species. The sediment samples were collected in the Mimi River basin from the Tsukabaru Dam to the sea in an area including 4 dams and 5 tributaries. In addition, the minerals in samples collected in 2014, before the start of the sediment sluicing operation, and from 2018 to 2020, after the start of the operation, were analyzed. An evaluation of the similarity of the sediment at each sampling point based on the X-ray diffraction peaks of mineral species showed that sediment distributed upstream was transported downstream in the year when the sediment sluicing was done. This result indicates that the sediment sluicing operation at dams ensured the continuity of the sediment distribution in the Mimi River basin. In addition, an investigation done in 2020 showed that sediment particles very similar to those of the upstream tributaries were deposited downstream because of extensive flooding caused by a large typhoon. The management of sediment transport has the greatest importance in a river basin where a dam is to be constructed. It is possible to trace the history of the sediment distribution and movement resulting from the operation of sediment sluicing by using sediment mineral analysis.
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Application of Coagulation and Foam Concentration Method to Quantify Waterborne Pathogens in River Water Samples Reviewed International coauthorship
Suzuki Y., Jikumaru A., Tamai S., Nukazawa K., Masago Y., Ishii S.
Water (Switzerland) 14 ( 22 ) 3642 2022.11
Authorship：Lead author, Corresponding author Language：English Publishing type：Research paper (scientific journal) Publisher：Water (Switzerland)
One of the major challenges in detecting waterborne pathogens is the low concentration of the target bacteria in water. In this study, we applied the coagulation and foam concentration method to obtain DNA from water samples collected from upstream, near an estuary. The DNA samples were analyzed using 16S rRNA gene sequencing to clarify the microbial community shifts and to identify potentially pathogenic bacteria. Bacterial communities changed as the river flowed downstream, most likely influenced by land use and human activities such as the discharge of wastewater-treatment plant effluent. Based on the 16S rRNA gene amplicon sequencing, potentially pathogenic bacteria were detected with greater than 0.1% of their relative abundances. Among these, Yersinia ruckeri and Pseudomonas alcaligenes were widely detected in the river water. In addition, digital PCR (dPCR) was used to quantify major waterborne pathogens. Shiga toxin-producing Escherichia coli (STEC), Shigella spp., and Campylobacter jejuni were all below the limit of detection. In contrast, general E. coli, which has the beta-D-glucuronidase gene (uidA) were detected by dPCR (copies/100 mL) at similar levels to those measured using the culture-based method (as colony forming units/100 mL). These results suggest that the coagulation and foam concentration method is useful for concentrating microbes and obtaining DNA from river water samples for environmental monitoring.
DOI： 10.3390/w14223642
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Effects of the Japanese Nitrate Directive Plan (NDP) to curb groundwater nitrate-nitrogen content in the Miyakonojo River basin Reviewed
Yu, Z.-Q., K. Nakagawa, R. Berndtsson, T. Hiraoka, and Y. Suzuki
Journal of Hydrology 615 128563 2022.10
Authorship：Last author Language：English Publishing type：Research paper (scientific journal)
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瀬-淵の水理学的変動を考慮した機械学習による底生動物分布モデルの構築 Reviewed
田中凌央, 糠澤桂, 宇都宮将, 鈴木祥広
土木学会論文集G（環境）地球環境研究論文集 第30巻 78 ( 5 ) I_7 - I_16 2022.9
Authorship：Last author Language：Japanese Publishing type：Research paper (scientific journal)
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Mori M., Gonzalez Flores R., Suzuki Y., Nukazawa K., Hiraoka T., Nonaka H.
Harmful Algae 117 102273 2022.8
Authorship：Last author Language：English Publishing type：Research paper (scientific journal) Publisher：Harmful Algae
Machine learning, Deep learning, and water quality data have been used in recent years to predict the outbreak of harmful algae, especially Microcystis, and analyze outbreak causes. However, for various reasons, water quality data are often High-Dimension, Low-Sample- Size (HDLSS), meaning the sample size is lower than the number of dimensions. Moreover, imbalance problems may arise due to bias in the occurrence frequency of Microcystis. These problems make predicting the occurrence of Microcystis and analyzing its causes with machine learning difficult. In this study, a machine learning model that applies Feature Engineering (FE) and Feature Selection (FS) algorithms are used to predict outbreaks of Microcystis and analyze the outbreak factors from imbalanced HDLSS water quality data. The prediction performance was verified with binary classification to determine whether Microcystis would occur in the future by applying three machine learning models to four data patterns. The cause analysis of Microcystis occurrence was performed by visualizing the results of applying FE and FS. For the test data, the predictive performance of FE and FS methods was significantly better than that of the conventional method, with an accuracy of .108 points and an F-value of .691 points higher than the conventional method. A prediction performance increase was observed with a smaller model capacity. Data-driven analysis suggested that total nitrogen, chemical oxygen demand, chlorophyll-a, dissolved oxygen saturation, and water temperature are associated with Microcystis occurrences. The results also indicated that basic statistics of the water quality distribution (especially mean, standard deviation, and skewness) over a year, not the concentrations of water components, are related to the occurrence of Microcystis. These are new findings not found in previous studies and are expected to contribute significantly to future studies of algae. This study provides a method for analyzing water quality data with high-dimensionality and small samples, imbalance problems, or both.
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Effects of Artificial River Water on PEM Water Electrolysis Performance Reviewed
Yoshimura, R., Wai, S., Ota, Y., Nishioka, K., Suzuki, Y.
Catalysts 12 ( 9 ) 934 2022.8
Language：English Publishing type：Research paper (scientific journal)
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Persistence of Antibiotic-Resistant Escherichia coli Strains Belonging to the B2 Phylogroup in Municipal Wastewater under Aerobic Conditions Reviewed
Xie, H., Ogura, Y. and Suzuki, Y.
Antibiotics 11 ( 2 ) 2022.2
Authorship：Last author, Corresponding author Language：English Publishing type：Research paper (scientific journal)
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Antibiotic-resistant Escherichia coli isolated from dairy cows and their surrounding environment on a livestock farm practicing prudent antimicrobial use Reviewed
Suzuki, Y., Hiroki, H., Xie, H., Nishiyama, M., Sakamoto, S.H., Uemura, R., Nukazawa, K., Ogura, Y., Watanabe, T. and Kobayashi, I.
International Journal of Hygiene and Environmental Health 240 113930 2022.1
Authorship：Lead author, Corresponding author Language：English Publishing type：Research paper (scientific journal)
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Hydrological modeling to assess watershed-scale flow alterations induced by dams and climate change Reviewed
Mineda H., Nukazawa K., Tanimura Y., Suzuki Y.
Proceedings of the IAHR World Congress 1537 - 1546 2022
Publishing type：Research paper (scientific journal) Publisher：Proceedings of the IAHR World Congress
Hydrological alterations can reduce aquatic biodiversity by disrupting the natural flow regimes that characterize the life cycles oforganisms. However, past studies have faced difficulties in quantifying the impacts of dams and climate change, which are major drivers of hydrological alterations. Here, we aimed to evaluate and compare the flow regime alterations caused by dams and climate change throughout the Omaru River catchment, Japan, using a distributed hydrological model. First, to assess the impacts ofdam and climate change independently, we performed runoff analyses using either dam discharge orfuture climatic data (two future periods χ three representative concentration pathways; RCPs). Subsequently, we derived indicators of hydrologic alterations (İHA) to quantify changes in flow alterations by comparing them to İHA under natural conditions (i.e., without dam or climate change data). The runoff analyses showed high reproducibility throughout the study period (Nash-Sutcliffe efficiency = 0.921-0.964). We found that dams altered flow regimes more than climate change, especially under conservative RCP scenarios (RCP2.6 and RCP4.5). However, on a catchment-scale standpoint, climate change induced wider ranges of flow alterations, such as low flow metrics along the tributaries and uppermost main stem, suggesting a watershed-level shrinkage in important corridors of aquatic organisms by reducing upstream length and water level. We also observed that the altered flow regimes by water withdrawals were ameliorated by the confluence of tributaries and downstream hydropower outflows. Our approach, which used a distributed hydrological model, developed a better understanding of flow alterations by dams and climate change.
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Enhancement of sunlight irradiation for wastewater disinfection by mixing with seawater Reviewed
uzuki, Y., Uno, M., Nishiyama, M., Nukazawa, K. and Masago, Y.
Journal of Water and Health 19 ( 5 ) 836 - 845 2021.10
Authorship：Lead author, Corresponding author Language：English Publishing type：Research paper (scientific journal)
DOI： 10.2166/wh.2021.153
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Plant debris are hotbeds for pathogenic bacteria on recreational sandy beaches Reviewed
Suzuki, Y., Shimizu, H., Kuroda, T., Takada, Y. and Nukazawa, K.
Scientifc Reports 11 11496 2021.6
Language：English Publishing type：Research paper (scientific journal)
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Comparison of antibiotic resistance profile of Escherichia coli between pristine and human-Impacted sites in a river Reviewed
Nishimura, E., Nishiyama, M., Nukazawa, K. and Suzuki, Y.
Antibiotics 10 575 2021.5
Language：English Publishing type：Research paper (scientific journal)
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都城盆地における地下水中の硝酸性窒素濃度と降水量の関係分析 Reviewed
平岡透, 中川啓, 野中尋史, 廣田雅春, 鈴木祥広
水文・水資源学会誌 34 ( 5 ) 303 - 310 2021.5
Authorship：Last author Language：Japanese Publishing type：Research paper (scientific journal)
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Mineralogical fingerprinting to characterize spatial distribution of coastal and riverine sediments in southern Japan Reviewed
Nukazawa, K., Itakiyo, T., Ito, K., Sato, S., Oishi, H. and Suzuki, Y.
Catena 203 105323 2021.3
Language：English Publishing type：Research paper (scientific journal)
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土地利用情報を加えた時空間分析による地下水中の硝酸性窒素濃度の補間 Reviewed
平岡透, 中川啓, 野中尋史, 廣田雅春, 鈴木祥広
水文・水資源学会誌 34 ( 3 ) 193 - 203 2021.3
Language：Japanese Publishing type：Research paper (scientific journal)
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Groundwater nitrogen response to regional land-use management in South Japan Reviewed International coauthorship
Yu, Z.-Q., Nakagawa, K., Berndtsson, R., Hiraoka, T. and Suzuki, Y.
Environmental Earth Sciences 80 ( 18 ) 2021
Authorship：Last author Language：English Publishing type：Research paper (scientific journal)
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Gradients of flow regulation shape community structures of stream fishes and insects within a catchment subject to typhoon events Reviewed
Nukazawa, K., Shirasaka, K., Kajiwara, S., Saito, T., Irie, M. and Suzuki, Y.
Science of The Total Environment 748 141398 2020.12
Language：English Publishing type：Research paper (scientific journal)
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Ogura Y., Ueda T., Nukazawa K., Hiroki H., Xie H., Arimizu Y., Hayashi T., Suzuki Y.
Scientific Reports 10 ( 1 ) 2020.12
Language：Japanese Publishing type：Research paper (scientific journal) Publisher：Scientific Reports
The dissemination of antimicrobial-resistant bacteria in environmental water is an emerging concern in medical and industrial settings. Here, we analysed the antimicrobial resistance of Escherichia coli isolates from river water and sewage by the use of a combined experimental phenotypic and whole-genome-based genetic approach. Among the 283 tested strains, 52 were phenotypically resistant to one or more antimicrobial agents. The E. coli isolates from the river and sewage samples were phylogenetically indistinguishable, and the antimicrobial-resistant strains were dispersedly distributed in a whole-genome-based phylogenetic tree. The prevalence of antimicrobial-resistant strains as well as the number of antimicrobials to which they were resistant were higher in sewage samples than in river samples. Antimicrobial resistance genes were more frequently detected in strains from sewage samples than in those from river samples. We also found that 16 river isolates that were classified as Escherichia cryptic clade V were susceptible to all the antimicrobials tested and were negative for antimicrobial resistance genes. Our results suggest that E. coli strains may acquire antimicrobial resistance genes more frequently and/or antimicrobial-resistant E. coli strains may have higher rates of accumulation and positive selection in sewage than in rivers, irrespective of their phylogenetic distribution.
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Antimicrobial resistance is more prevalent in various lineages of Escherichia coli strains isolated from sewage than in those from rivers Reviewed
Ogura, Y., Ueda, T., Nukazawa, K., Hiroki, H., Xie, H., Arimizu, Y., Hayashi, T. and Suzuki, Y.
Scientific Reports 10 17880 2020.10
Language：English Publishing type：Research paper (scientific journal)
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高濁度水への環境DNA法の適用に向けたろ過・濃縮手法の基礎的検討 Reviewed
糠澤桂, 深川柊, 鈴木祥広
土木学会論文集G（環境） 76 ( 5 ) I_19 - I_26 2020.9
Language：Japanese Publishing type：Research paper (scientific journal)
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分布型流出モデルを用いた小丸川水系におけるダム・堰による流況改変の縦断的評価 Reviewed
峯田陽生, 糠澤桂, 中尾彰吾, 鈴木祥広
土木学会論文集G（環境） 76 ( 5 ) I_65 - I_74 2020.9
Language：Japanese Publishing type：Research paper (scientific journal)
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Jikumaru A., Ishii S., Fukudome T., Kawahara Y., Iguchi A., Masago Y., Nukazawa K., Suzuki Y.
Journal of Bioscience and Bioengineering 130 ( 1 ) 76 - 81 2020.7
Publishing type：Research paper (scientific journal) Publisher：Journal of Bioscience and Bioengineering
The quantification of pathogens is important for assessing water safety and preventing disease outbreaks. Culture-independent approaches, such as quantitative PCR (qPCR) and digital PCR (dPCR), are useful techniques for quantifying pathogens in water samples. However, since pathogens are usually present at low concentrations in water, it is necessary to concentrate microbial cells before extracting their DNA. Many existing microbial concentration methods are inefficient or take a long time to perform. In this study, we applied a coagulation and foam separation method to concentrate environmental water samples of between 1000 and 5000 mL to 100 μL of DNA (i.e., a 1–5 × 104-fold concentration). The concentration process took <1 h. The DNA samples were then used to quantify various target pathogens using dPCR. One gene, the Shiga toxin gene (stx2) of Shiga toxin-producing Escherichia coli, was detected at 32 copies/100 mL in a river water sample. The coagulation and foam concentration method followed by dPCR reported herein is a fast, sensitive, and reliable method to quantify pathogen genes in environmental water samples.
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Are bacteria potential sources of fish environmental DNA? Reviewed
Nukazawa, K., Akahoshi, K., Suzuki, Y.
PLoS One 15 ( 3 ) e0230174 2020.3
Language：English Publishing type：Research paper (scientific journal)
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Fast, sensitive, and reliable detection of waterborne pathogens by digital PCR after coagulation and foam concentration Reviewed
Jukumaru, A., Ishii, S., Fukudome, T., Kawahara, Y., Iguchi, A., Masago, Y., Nukazawa, K., Suzuki, Y.
Journal of Bioscience and Bioengineering 130 ( 1 ) 76 - 81 2020.2
Language：English Publishing type：Research paper (scientific journal)
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Preliminary assessment of the impacts of sediment sluicing events on stream insects in the Mimi River, Japan Reviewed
Nukazawa, K., Kajiwara, S., Saito, T., Suzuki, Y.
Ecological Engineering 145 105726 2020.1
Language：English Publishing type：Research paper (scientific journal)
Dam sedimentation is a crucial issue that interferes with flood control and electric power generation. To address this, sediment dredging, bypass tunnel, flushing, and sluicing have been applied. Despite the potential impacts of these operations on stream environments, few studies have explored the environmental/ecological consequences of such regime shifts in sediment dynamics. Specifically, impacts of sediment sluicing on stream fauna have never been reported. This study assessed primary impacts of sediment sluicing events operated with the two cascade dams (the Saigo and Ouchibaru Dams) on stream insects in the lower Mimi River, Japan. The sediment sluicing, accompanied by a major flooding event in the river, was first operated in September 2017. Stream insect data downstream of the four cascade dams, including the two sluicing dams and a reference river, were collected yearly or biyearly in winter and summer from 2010 to 2018. Following the initiation of retrofitting the Saigo Dam for optimizing sediment sluicing, a downstream reach of the dam experienced marked perturbations in terms of both individual density and species richness. The density and richness dramatically decreased and the community significantly differed in winter 2017 from pre-impact conditions. The density, richness, and com- munity composition subsequently recovered in winter 2018, even after the sediment sluicing impact, suggesting that the anticipated negative ecological impacts of the sluicing are limited. Non-metric multidimensional scaling and permutational multivariate analysis of variance revealed distinct differences in communities between summer and winter samples at non-regulated sites or sites farther downstream of the dam that are characterized by fewer Simuliidae in summer and relatively abundant Heptageniidae. This could serve as a reference for assessments of ecological consequences of sediment sluicing in the region.
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Growth and antibiotic resistance acquisition of Escherichia coli in a river that receives treated sewage effluent Reviewed
Suzuki, Y., Hashimoto, R., Xie, H., Nishimura, E., Nishiyama, M., Nukazawa, K., Ishii, S.
Science of the Total Environment 690 696 - 704 2019.8
Language：English Publishing type：Research paper (scientific journal)
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Using mineral compositions to indicate the origin of sediments in a tidal flat of an estuarine marsh Reviewed
Suzuki Y., Arao Y., Ito K., Yoshitake H., Hamaguchi K.
Coastal Engineering Journal 61 ( 3 ) 354 - 362 2019.7
Language：English Publishing type：Research paper (scientific journal) Publisher：Coastal Engineering Journal
© 2019 Japan Society of Civil Engineers. Given the importance of tidal flats as habitats for a wide range of organisms, a considerable amount of related research has accumulated. However, in Japan, as elsewhere in the world, tidal flats are disappearing because of increasing seaside population, urbanization, and development of coastal industries. We investigated the sediment characteristics of Tsuyabaru Marsh in Japan, using X-ray fluorescence and X-ray diffraction (XRD) analyses to trace their sources. The estuarine Tsuyabaru Marsh comprises a tidal flat, the peripheral basin, the Ooyodo River, and the Yae River. The mineral components of the tidal flat sediment were quartz, mica minerals, kaolinite, plagioclase, and dolomite. To trace the sediment source and characterize the sediment in the Tsuyabaru Marsh, cluster analysis was applied to the peak XRD intensity ratios. A strong similarity was demonstrated between the sediments collected from the tidal flat and the Ooyodo River. A comparably strong similarity was found between sediments from the bottom of Tsuyabaru Marsh and the upstream Yae River section. Our analysis helps understand the sources and distribution of sediments in estuarine marshes.
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SUZUKI Yoshihiro, ENDO Keigo, TAIKO Wakana, NUKAZAWA Kei, FURUHASHI Yuichi, CHUGANJI Nobuaki
Journal of Japan Society on Water Environment 42 ( 6 ) 269 - 275 2019.6
Language：Japanese Publishing type：Research paper (scientific journal) Publisher：Japan Society on Water Environment
In the present study, we investigated the relationship between 11 properties of digested sludge and the optimal dosage ratio of polymer flocculant, assuming a conditioning process for sludge fed into a dewatering centrifuge. Furthermore, the study was focused on the supernatant phase (mixed phase of colloidal matter and dissolved matter) obtained by centrifugal separation of sludge, and a list of the properties of the supernatant phase was created. We then attempted to identify the properties that govern the optimal dosage. As a result, no correlation between total solids and the optimal injection ratio was observed. Therefore, the dosage was defined as the absolute quantity of polymer flocculant per 100 grams of sludge (g/100 g sludge = % per sludge weight) . As a result of examining its relationship with various properties, the strongest correlation was observed between the anion concentration of the supernatant phase and the optimal quantity of polymer flocculant, with r=0.73. A correlation was also found between the optimal quantity of polymer flocculant and the turbidity of the supernatant phase (r=0.68) . We thus found that the optimal quantity of polymer flocculant can be predicted simply by centrifuging the raw sludge and measuring the turbidity of the supernatant phase.
DOI： 10.2965/jswe.42.269
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Optimum Condition for Valuable Seaweed Growth to Utilize Treated Sewage as a Nutrient Source Reviewed
Suzuki, Y., Nakada, K., Nukazawa, K., Yamanishi, H.
Journal of Environmental Science and Technology 12 ( 1 ) 17 - 25 2019.1
Language：English Publishing type：Research paper (scientific journal)
DOI： 10.3923/jest.2019
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A highly efficient method for concentrating DNA from river water by combined coagulation and foam separation Reviewed
Suzuki, Y., Imafuku, Y., Nishiyama, M., Teranishi, K., Nukazawa, K., Ogura, Y.
Separation Science and Technology 2019.1
Language：English Publishing type：Research paper (scientific journal)
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都城盆地における地下水の硝酸性窒素濃度の時空間分析による補間 Reviewed
平岡透, 豊満幸雄, 中川啓, 野中尋史, 廣田雅春, 鈴木祥広
水文・水資源学会誌 32 ( 1 ) 23 - 34 2019.1
Language：Japanese Publishing type：Research paper (scientific journal)
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Electricity generation from sweet potato-shochu waste using microbial fuel cells
Iigatani R., Ito T., Watanabe F., Nagamine M., Suzuki Y., Inoue K.
Journal of Bioscience and Bioengineering 2019
Language：Japanese Publishing type：Research paper (scientific journal) Publisher：Journal of Bioscience and Bioengineering
© 2019 The Society for Biotechnology, Japan Electricity generation and treatment of sweet potato-shochu waste, acidic and organic-rich slurry, was examined using cassette-electrode microbial fuel cells (CE-MFCs). Among CE-MFCs with raw (73 g-chemical oxygen demand chromium COD Cr /L) and different concentration of diluted sweet potato-shochu waste (0.5, 1, 5, 10, and 20 g-COD Cr /L) without pH control, the maximum power density (1.2 W/m 3 ) and COD Cr removal efficiency (67.4 ± 1.8%) were observed in the CE-MFCs with 10 g-COD Cr /L shochu waste. The concentration of organic acid was decreased to below the quantification limits during the 9-day operation in the CE-MFC with 10 g-COD Cr /L shochu waste. During the same period, the electrolyte pH was increased from 4.2 to 6.6. Microbial community analysis revealed that the genus Clostridium (75.4%) was predominant in the CE-MFCs with raw shochu waste, whereas Bacteroides (65.3%) and Clostridium (12.1%) were predominant in the CE-MFCs with 10 g-CODCr/L shochu waste.
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Development of Rapid and Simple Bioassay Using Seaweed <i>Pyropia yezoensis</i> Invited
Suzuki Yoshihiro, Hirayama Shota
Marine Engineering 54 ( 6 ) 898 - 904 2019
Language：Japanese Publishing type：Research paper (scientific journal) Publisher：The Japan Institute of Marine Engineering
Bioassays are a useful tool for assessing the effect of effluents on organisms. However, there are only a few bioassays established using marine organisms. Moreover, conventional bioassay procedures require enormous amounts of time and labor. In this study, the authors have developed a rapid and simple bioassay using seaweed <i>Pyropia yezoensis</i> (conchospores and juvenile sporophytes), and bioassay tests were performed upon a 96 well microplate. The growth rate of an endpoint was determined by fluorescence intensity of chlorophyll using a plate reader. Through daily monitoring, this method could calculate the most minimum EC<sub>50</sub> for major heavy metals and toxic compounds. A trial with sporophytes could detect the effect of harmful substances more sensitively than a test using conchospores. In addition, the sporophytes test showed detection sensitivity to toxicants similar to that of a test with microalga <i>Skeletonema marinoi-dohrnii</i>. The sensitivities of conchospores and sporophytes tests to heavy metals were equal to those with various other seaweeds. We propose a rapid and simple seaweed bioassay using a microplate and a fluorescence plate reader.
DOI： 10.5988/jime.54.898
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牧場における畜産動物と畜舎周辺に生息する野生小動物の薬剤耐性大腸菌の実態調査 Reviewed
廣木颯, 畔柳聴, 坂本信介, 小林郁雄, 上村涼子, 糠澤桂, 鈴木祥広
土木学会論文集G（環境） 2018.12
Language：Japanese Publishing type：Research paper (scientific journal)
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Simulating the advection and degradation of the environmental DNA of common carp along a river Reviewed
Nukazawa, K., Hamasuna, Y. and Suzuki, Y.
Environmental Science and Technology 52 ( 18 ) 10562 - 10570 2018.9
Language：English Publishing type：Research paper (scientific journal)
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マニラ首都圏におけるデング熱媒介蚊の産卵活動に関わる因子の時空間的分析 Reviewed
糠澤桂, 西元峻哉, 鈴木祥広, 渡辺幸三
土木学会論文集G（環境） 74 ( 5 ) I_79 - I_85 2018.9
Language：Japanese Publishing type：Research paper (scientific journal)
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都城盆地における地下水の硝酸性窒素濃度と土地利用の関係分析 Reviewed
平岡透, 豊満幸雄, 中川啓, 野中尋史, 廣田雅春, 鈴木祥広
土木学会論文集G（環境） 74 ( 5 ) I_87 - I_94 2018.9
Language：Japanese Publishing type：Research paper (scientific journal)
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宮崎県耳川における発電用ダムによる流況改変が河川生態系へ与える影響 Reviewed
白坂厚大, 糠澤桂, 鈴木祥広
土木学会論文集G（環境） 74 ( 5 ) I_139 - I_146 2018.9
Language：Japanese Publishing type：Research paper (scientific journal)
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Investigation of <i><b>Escherichia coli</b></i> in Urban Steam with Inflow of Treated Wastewater Reviewed
SUZUKI Yoshihiro, NISHIYAMA Masateru, NUKAZAWA Kei, ISHII Satoshi
Journal of Japan Society on Water Environment 41 ( 2 ) 19 - 26 2018.3
Language：Japanese Publishing type：Research paper (scientific journal) Publisher：Japan Society on Water Environment
There is growing concern for the applicability of <i>Escherichia</i> <i>coli</i> as a fecal indicator bacterium in the water environment because <i>E.</i> <i>coli</i> has been reported to regrow in a variety of environments. We investigated longitudinal variation in <i>E.</i> <i>coli</i> counts along a small channel which receives the effluent of treated wastewater. The two fecal indicator bacteria, <i>E.</i> <i>coli</i> and Enterococci, were enumerated, and these bacterial fluxes were calculated from bacteria counts and river flow. As a result, the flux of <i>E.</i> <i>coli</i> was larger downstream of the effluent site than the sum of the fluxes upstream and in the effluent. A high <i>E.</i> <i>coli</i> count was detected in the riverbed sediment of a downstream site. In addition, pulsed-field gel electrophoresis revealed that the genotypes of <i>E.</i> <i>coli</i> isolated from the upstream water, periphyton, and riverbed sediment samples were concordant (similarity = 1.0) . These results indicate that <i>E.</i> <i>coli</i> survived and accumulated in riverbed periphyton and sediment and that <i>E.</i> <i>coli</i> may regrow in a small stream that is strongly affected by treated wastewater. When we assess the fecal pollution in rivers, it is necessary to consider the possibility of <i>E.</i> <i>coli</i> regrowth.
DOI： 10.2965/jswe.41.19
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Suzuki Y., Niina K., Matsuwaki T., Nukazawa K., Iguchi A.
Journal of Environmental Science and Health - Part A Toxic/Hazardous Substances and Environmental Engineering 53 ( 2 ) 160 - 173 2018.1
Language：English Publishing type：Research paper (scientific journal) Publisher：Journal of Environmental Science and Health - Part A Toxic/Hazardous Substances and Environmental Engineering
© 2018 Taylor & Francis Group, LLC. The aim of this study was to rapidly and effectively analyze coliforms, which are the most fundamental indicators of water quality for fecal pollution, using matrix-assisted laser desorption ionization time-of-flight mass spectrometry (MALDI-TOF MS). Coliform bacteria were isolated from municipal sewage, river water, and groundwater. For each sample, 100 isolates were determined by MALDI-TOF MS. In addition, these same 100 isolates were also identified via 16S rRNA gene sequence analysis. Obtained MALDI-TOF MS data were compared with the 16S rRNA sequencing analysis, and the validity of MALDI-TOF MS for classification of coliform bacteria was examined. The concordance rate of bacterial identification for the 100 isolates obtained by MALDI-TOF MS analysis and 16S rRNA gene sequence analysis for sewage, river water, and ground water were 96%, 74%, and 62% at the genus level, respectively. Among the sewage, river water, and ground water samples, the coliform bacterial flora were distinct. The dominant genus of coliforms in sewage, river water, and groundwater were Klebsiella spp., Enterobacter spp., and Serratia spp., respectively. We determined that MALDI-TOF MS is a rapid and accurate tool that can be used to identify coliforms. Therefore, without using conventional 16S rRNA sequencing, it is possible to rapidly and effectively classify coliforms in water using MALDI-TOF MS.
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Byambaa M., Dolgor E., Shiomori K., Suzuki Y.
Journal of Environmental Science and Technology 11 ( 1 ) 1 - 9 2018
Language：English Publishing type：Research paper (scientific journal) Publisher：Journal of Environmental Science and Technology
© 2018 Maralmaa Byambaa et al. Background and Objective: Even today, a strong need exists for the quick and easy removal and recovery of heavy metals from industrial wastewater at low cost. In this study, recovery of heavy metals from artificial wastewater containing Cr, Cu, Cd, Pb and Mo (each concentration, 10 mg L- 1 ) by precipitation and foam separation using lime and milk casein was investigated. In addition, the performance of foam separation was tested using mining tailing water collected from a mining plant. Materials and Methods: Lime was used as an alkaline agent for heavy-metal precipitation. Milk casein functioned as both a collector and a frother for foam separation. After the precipitation process, casein was added to the precipitated wastewater and foam separation was carried out. The removal efficiencies of heavy metals were determined by inductively plasma spectrometry. Results: Under the optimum alkaline condition at pH 9, where the pH was adjusted by lime addition and a casein dosage of 15 mg L- 1 , 96% of Cr, Cu, Cd and Pb were removed from the wastewater and recovered in the foam, however, Mo remained in the water. When the pH of the treated water was re-adjusted at 5.3 and the water was reprocessed by foam separation, 76% of Mo was removed from the treated water. To demonstrate the effectiveness of the proposed precipitation and foam separation method under actual conditions, it was applied to mining tailing water collected from an ore-mining facility in Mongolia. The removal efficiencies of heavy metals such as Mn, Fe and Cu included in the mining tailing water were greater than 85%. Furthermore, more than 90% of the suspended solids were also removed from the tailing water. Conclusion: The casein enabled the collection and recovery of the precipitation components of heavy metals within a total processing time of 10 min. Precipitation and foam separation using lime and casein is an effective and adaptable method for treating industrial effluents that contain heavy metals.
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Effects of bacterial pollution caused by a strong typhoon event and the restoration of a recreational beach: Transitions of fecal bacterial counts and bacterial flora in beach sand Reviewed
Suzuki, Y., Teranishi, K., Matsuwaki, T., Nukazawa, K., Ogura, Y.
Science of the Total Environment 640-641 52 - 56 2018
Language：English Publishing type：Research paper (scientific journal)
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Nukazawa K., Kihara K., Suzuki Y.
Journal of Hydrology 555 288 - 297 2017.12
Language：English Publishing type：Research paper (scientific journal) Publisher：Journal of Hydrology
© 2017 Elsevier B.V. Rivers fulfill an essential ecological role by forming networks for material transport from upland forests to coastal areas. The way in which dams affect the organic and inorganic cycles in such systems is not well understood. Herein, we investigated the longitudinal profiles of the various components of the water chemistry across three cascade dams in Japan: the Yamasubaru Dam, Saigou Dam, and Ohuchibaru Dam, which are situated along the sediment-productive Mimi River in different flow conditions. We analyzed the following water quality components: suspended solids (SS), turbidity, total iron (TFe), dissolved iron (DFe), total organic carbon (TOC), total nitrogen (TN), total phosphorus (TP), humic substance (HS), and major ionic components (Na + , Mg 2+ , Ca 2+ , Cl − , NO 3− , and SO 4 2− ) in the downstream channels of the three dams during the low–intermediate-flow and high-flow events from 2012 to 2014. We estimated hourly loads of each component using hourly turbidity data and discharge data (i.e., L–Q model) separately, and the results are integrated to estimate the annual fluxes. The annual fluxes between the methods were compared to verify predictability of the conventional L–Q models. Annual flux of TOC, TN, DFe, and HS estimated by the turbidity displayed similar values, whereas the flux of SS, TFe, and TP tended to increase downstream of the dams. Among the dams, estimated flux proportions for TP and TFe were higher during high-flow events (74%–94%). Considering geographic conditions (e.g., absence of major tributary between the dams), the result implies that accumulated TP and TFe in the reservoirs may be flushed and transported downstream with SS over the short height dams during flood events. Assuming this process, the reservoir dams probably make only a fractional contribution to the organic and inorganic transport in the catchment studied. The percent flux errors for SS, TFe, and TP fluxes ranged from −7.2% to −97% (except for the TP flux in 2013), which highlights the risk of underestimating these components when using an L–Q model.
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Antibiotic resistance profiling and genotyping of vancomycin-resistant enterococci collected from an urban river basin in the provincial city of Miyazaki, Japan Reviewed
Nishiyama M, Ogura Y, Hayashi T, Suzuki Y
Water 9 ( 79 ) 2017.1
Language：English Publishing type：Research paper (scientific journal)
DOI： 10.3390/w9020079
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Distribution of antimicrobial resistant Salmonella in an urban river that flows through the provincial city of Miyazaki, Japan Reviewed
Suzuki Y, Ushijima M.
Water and Environment Journal 30 290 - 297 2016.12
Language：English Publishing type：Research paper (scientific journal)
DOI： 10.1111/wej.12194
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エジプト国ナイルデルタ流域における集落排水処理施設の構築とその運転状況 Reviewed
小木曽凡芳, 大石貴行, 鈴木祥広
環境技術 45 ( 9 ) 484 - 492 2016.9
Language：Japanese Publishing type：Research paper (scientific journal)
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Temporal variability in genetic patterns and antibiotic resistance profiles of enterococci isolated from human faeces Reviewed
Nishiyama M, Shimauchi H, Suzuki Y
Microbes and Environments 31 ( 2 ) 182 - 185 2016.7
Language：English Publishing type：Research paper (scientific journal)
Temporal variabilities in the genetic patterns and antibiotic resistance profiles of enterococci were monitored over a 7-month
period. Enterococcus faecalis isolates (103 strains) collected from feces showed only one genetic pattern and antibiotic resistance
profile within 0 d and 30 d. In contrast, after 60 d and 90 d, the genetic patterns and antibiotic resistance profiles of all E.
faecalis isolates (8 strains) clearly differed within 30 d. These results indicate that the genetic patterns and antibiotic resistance
profiles of E. faecalis in human feces changed to completely dissimilar patterns between 1 and 2 months. -
Concentration of MS2 Phage in River Water by a Combined Ferric Colloid Adsorption and Foam Separation-Based Method, with Ms2 Phage Leaching from Ferric Colloid Reviewed
Suzuki Y, Kobayashi T, Nishiyama M, Kono T
Journal of Bioscience and Bioengineering 122 ( 2 ) 252 - 256 2016.6
Language：English Publishing type：Research paper (scientific journal)
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ナイルデルタの農業排水路における水質汚濁の実態調査 Reviewed
小木曽凡芳, 大石貴行, 鈴木祥広
環境技術 45 ( 4 ) 206 - 213 2016.4
Language：Japanese Publishing type：Research paper (scientific journal)
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TRACING THE SOURCE OF SEDIMENT IN HITOTSUSE DAM RESERVOIR USING MINERAL ANALYSIS Reviewed
ARAO Yasuhiro, ITOU Kenichi, OISHI Hiroyuki, MURAKAMI Toshiki, SUZUKI Yoshihiro
Journal of Japan Society of Civil Engineers, Ser. G (Environmental Research) 72 ( 2 ) 12 - 23 2016.4
Language：Japanese Publishing type：Research paper (scientific journal) Publisher：Japan Society of Civil Engineers
Sediments have become a serious problem in the management of the Hitotsuse Dam Reservoir (reservoir capacity: 261,361,500 m3), Miyazaki, Japan. The prevention of sediments in reservoirs remains a challenge, because the catchments can contain many landslip areas and the strata architecture is complex. In this study, we investigate the source of the sediments in the reservoir using mineral analysis. The core sample was collected by a boring machine from a 16 m sediment depth. To assess the nature of the particles, landslide soils accumulated in catchments of the Hitotsuse Dam were sampled and analyzed. Energy dispersive X-ray fluorescence (ED-XRF) and X-ray diffraction (XRD) were used to determine the component composition and mineral composition of the sediments, respectively. Cluster analyses were performed to evaluate the similarity in the component and mineral compositions of each sample. Component and mineral compositions of core samples indicated high similarities with the landslide soil to three samples out of 60 samples taken at 22 points. The points of three samples locate along the same stratum. It was strongly suggested that the sediments were continuously supplied from the same stratum located in the upper river basin. This method has the potential to determine the substances that release sediments in reservoirs and the location of the substances in the soil. Appropriate countermeasures to reduce the accumulation of sediments can then be taken at those specific locations.
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二液調質による下水汚泥脱水ケーキの低含水化に関する基礎的研究 Reviewed
鈴木祥広, 荒生靖大, 吉田在秀, 菊川哲生, 伊藤貫浩, 仲元寺宣明, 浜本洋一
用水と廃水 57 ( 9 ) 687 - 695 2015.9
Language：Japanese Publishing type：Research paper (scientific journal)
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火山灰凝集材による濁水の凝集特性 Reviewed
鈴木祥広, 玄晄植, 吉野内謙, 伊藤健一, 和田信一郎
用水と廃水 57 ( 3 ) 193 - 201 2015.3
Language：Japanese Publishing type：Research paper (scientific journal)
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Identification of Enterococcus faecium and Enterococcus faecalis as vanC-type vancomycin-resistant enterococci (VRE) from sewage and river water in the provincial city of Miyazaki, Japan Reviewed
Nishiyama T, Iguchi A, Suzuki Y.
Journal of Environmental Science and Health, Part A 50 16 - 25 2015.2
Language：English Publishing type：Research paper (scientific journal)
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NISHIYAMA Masateru, TAKESHITA Yusaku, SUZUKI Yoshihiro
Japan journal of water pollution research 38 ( 2 ) 57 - 65 2015.2
Language：Japanese Publishing type：Research paper (scientific journal) Publisher：Japan Society on Water Environment
Enterococci are fecal indicator bacteria that are widely distributed in water environments such as sewage, urban rivers, and coastal areas. In addition, nosocomial infectious diseases caused by vancomycin-resistant enterococci (VRE) have arisen in medical institutions. VRE have the potential to exist not only in hospital facilities but also in environmental water sources. In this study, VRE and other antibiotic-resistant enterococci isolated from sewage and rivers in the provincial city of Miyazaki, Japan, were investigated. There were no VRE in sewage and river water samples. However, vancomycin-intermediate-resistant enterococci were observed in both samples. The percentages of vancomycin-intermediate-resistant isolates from sewage and river water were 8.4% (20/239 isolates) and 1.9% (5/261 isolates), respectively. More than 60% of isolates from sewage and river water were resistant to erythromycin and tetracycline, which are universally applicable antibiotics. The monitoring performed monthly between June 2011 and July 2012 indicated that the percentages of antibiotic-resistant enterococci fluctuated every month. Enterococci resistant to various antibiotics exist ubiquitously in the water environment.
DOI： 10.2965/jswe.38.57
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Concentration of Cryptosporidium oocysts from river water by coagulation and foam separation combined with acid dissolution of ferric flocs Reviewed
Suzuki Y, Takida T.
Journal of Environmental Science and Health, Part A 50 311 - 316 2015.1
Language：English Publishing type：Research paper (scientific journal)
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Water Quality Purification for Agriculture Drain in the Nile Delta by the Micro Bubbles
OGISO Tsuneyoshi, OISHI Takayuki, SUZUKI Yoshihiro
J. Env. cons. eng 44 ( 4 ) 220 - 227 2015
Language：Japanese Publishing type：Research paper (scientific journal) Publisher：Society of Environmental Conservation Engineering
DOI： 10.5956/jriet.44.220
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模擬家畜を用いた埋却実験による環境負荷物発生挙動に関する研究 Reviewed
関戸知雄, 藤原尚洋, 土手裕, 鈴木祥広, 稲垣仁根, 森田哲夫
土木学会論文集G（環境） 70 III_457 - III_467 2014.11
Language：Japanese Publishing type：Research paper (scientific journal)
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ダム貯水池における濁水長期化を引き起こす原因粒子の発生源追跡
村上俊樹, 太田勝康, 鈴木祥広電力土木
電力土木 369 ( 1 ) 37 - 41 2014.1
Language：Japanese Publishing type：Research paper (scientific journal)
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SEKITO Tomoo, FUJIWARA Naohiro, DOTE Yutaka, SUZUKI Yoshihiro, INAGAKI Hitone, MORITA Tetsuo
PROCEEDINGS OF ENVIRONMENTAL AND SANITARY ENGINEERING RESEARCH 70 ( 7 ) III_457 - III_467 2014
Language：Japanese Publishing type：Research paper (scientific journal) Publisher：Japan Society of Civil Engineers
In 2010, an foot-and-mouth disease epidemic occurred in Miyazaki Prefecture, Japan. Over the period from April to August 2010, almost 290,000 animals were culled and buried. The burial of these carcasses significantly increased people's awareness of environmental contamination. However, little information has been generated on environmental pollution from burial sites. In this study, the characteristics and contamination levels of leachate and gas produced at the burial site were determined using laboratory-scale columns that simulated the burial site. In the case of higher water injection intensity, solubilization of organic substances was initiated in the early stages of the experiment. When the ammonia concentrations in the column decreased to a level suitable for methane fermentation, the amount of gas generated started to increase because of an increase in methane gas production. In the case where water was not injected, a significantly smaller amount of gas was generated except in the early stages of the experiment. The amount of methane gas generated in the column was reduced with the use of sawdust. During the two-year experimental period, the residual carbon concentration was 60%-70% and 90% in the column with water injection and the column without water injection, respectively.
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A proposal of source tracking of fecal pollution in recreational waters by pulsed-field gel electrophoresis Reviewed
T. Furukawa, Y. Suzuki
Microbes and Environments 28 ( 4 ) 444 - 449 2013.11
Language：English Publishing type：Research paper (scientific journal)
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下水の応急措置的処理を目的とした無機粘土系凝集剤による簡易凝集沈殿 Reviewed
鈴木祥広, 椎屋朋子, 西山正晃, 島内英貴, 牛島理博, 関戸知雄
用水と廃水 55 ( 11 ) 823 - 830 2013.11
Language：English Publishing type：Research paper (scientific journal)
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Electricity generation from cattle manure slurry by cassette-electrode microbial fuel cells
Inoue Kengo, Ito Toshihiro, Kawano Yoshihiro, Iguchi Atsushi, Miyahara Morio, Suzuki Yoshihiro, Watanabe Kazuya
Journal of bioscience and bioengineering 116 ( 5 ) 610 - 615 2013.11
Language：Japanese Publishing type：Research paper (scientific journal) Publisher：公益社団法人日本生物工学会
Cassette-electrode microbial fuel cells (CE-MFCs) are efficient and scalable devices for electricity production from organic waste. Previous studies have demonstrated that CE-MFCs are capable of generating electricity from artificial wastewater at relatively high efficiencies. In this study, a single-cassette CE-MFC was constructed, and its capacity for electricity generation from cattle manure suspended in water (solid to water ratio of 1:50) was examined. The CE-MFC reactor was operated in batch mode for 49 days; electricity generation became stable 2 weeks after initiating the operation. The maximum power density was measured at 16.3 W m^<-3> on day 26. Sequencing analysis of PCR-amplified 16S rRNA gene fragments obtained from the original manure and from anode biofllms suggested that Chlorofiexi and Geobacteraceae were abundant in the anode biofllm (29% and 18%, respectively), whereas no Geobacteraceae sequences were detected in the original manure sample. The results of this study suggest that CE-MFCs can be used to generate electricity from water-suspended cattle manure in a scalable MFC system.
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Electricity generation from cattle manure slurry by cassette-electrode microbial fuel cells Reviewed
Inoue K., Ito T., Kawano Y., Iguchi A., Miyahara M., Suzuki Y., Watanabe K.
Journal of Bioscience and Bioengineering 116 ( 5 ) 610 - 615 2013.11
Language：English Publishing type：Research paper (scientific journal) Publisher：Journal of Bioscience and Bioengineering
Cassette-electrode microbial fuel cells (CE-MFCs) are efficient and scalable devices for electricity production from organic waste. Previous studies have demonstrated that CE-MFCs are capable of generating electricity from artificial wastewater at relatively high efficiencies. In this study, a single-cassette CE-MFC was constructed, and its capacity for electricity generation from cattle manure suspended in water (solid to water ratio of 1:50) was examined. The CE-MFC reactor was operated in batch mode for 49 days; electricity generation became stable 2 weeks after initiating the operation. The maximum power density was measured at 16.3Wm -3 on day 26. Sequencing analysis of PCR-amplified 16S rRNA gene fragments obtained from the original manure and from anode biofilms suggested that Chloroflexi and Geobacteraceae were abundant in the anode biofilm (29% and 18%, respectively), whereas no Geobacteraceae sequences were detected in the original manure sample. The results of this study suggest that CE-MFCs can be used to generate electricity from water-suspended cattle manure in a scalable MFC system. © 2013 The Society for Biotechnology, Japan.
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置砂施工に用いるダム碓砂の洗浄工程で発生する濁水の簡易凝集処理
鈴木祥広
河川 807 ( 10 ) 49 - 53 2013.10
Language：Japanese Publishing type：Research paper (scientific journal)
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河川定点におけるふん便指標細菌の遺伝子パターンの変遷 Reviewed
古川隼士, 島内秀貴, 鈴木祥広
環境技術 42 ( 10 ) 617 - 624 2013.10
Language：Japanese Publishing type：Research paper (scientific journal)
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Suzuki Y., Kajii S., Nishiyama M., Iguchi A.
Science of the Total Environment 450-451 148 - 154 2013.4
Language：English Publishing type：Research paper (scientific journal) Publisher：Science of the Total Environment
Pseudomonas aeruginosa is responsible for a number of opportunistic and nosocomial infections. However, very little information is available on the ecology of P. aeruginosa in water environments and its association with antimicrobial resistance. In this study, the distribution of P. aeruginosa and the resistance of P. aeruginosa isolates to various antibiotics were investigated from two rivers, Kiyotake and Yae that flow through Miyazaki City, Japan. P. aeruginosa was distributed widely along the river basins with counts ranging from 2-46. cfu/100. mL. The susceptibility of P. aeruginosa isolates collected from the rivers to various antibiotics was examined by minimum inhibitory concentration. Multidrug-resistant P. aeruginosa strains were not observed or isolated from either river. However, one piperacillin-resistant P. aeruginosa was detected among a total of 516 isolates, and this isolate was also resistant to cefotaxime and showed intermediate resistance to cefitazidime. Less than 1% of all isolates (n = 5) were resistant to imipenem, which is the most effective antibiotic against both Gram-negative and Gram-positive bacteria. However, all P. aeruginosa isolates were completely resistant to tetracyclines, which are the most commonly prescribed antibiotics. In advanced nations such as Japan where the majority of the population is urban and where medical services are widespread, antibiotic-resistant bacteria such as P. aeruginosa are likely to be widely distributed, even in apparently pristine rivers. © 2013 Elsevier B.V.
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Tracing the source of difficult to settle fine particles which cause turbidity in the Hitotsuse reservoir, Japan Reviewed
Murakami T, Suzuki Y, Oishi H, Ito K, Nakao T
Journal of Environmental Management 120 37 - 47 2013.3
Language：English Publishing type：Research paper (scientific journal)
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FURUKAWA TAKASHI, SUZUKI YOSHIHIRO
Microbes and Environments 28 ( 4 ) 444 - 449 2013
Language：Japanese Publishing type：Research paper (scientific journal) Publisher：Japanese Society of Microbial Ecology · The Japanese Society of Soil Microbiology
This study aimed to identify specific river sources of fecal contamination by applying pulsed-field gel electrophoresis (PFGE) to environmental water samples from a recreational beach in Japan. The genotypes of all <i>Enterococcus faecium</i> and <i>Enterococcus faecalis</i> strains used as indicators of fecal pollution on the recreational beach and rivers were analyzed by PFGE, and the PFGE profiles of the strains were classified at a 0.9 similarity level using dendrogram analysis. PFGE types of <i>E. faecium</i> isolated from Sakai River or urban drainage were classified in the same cluster. Therefore, the probable sources of fecal pollution on the recreational beach were Sakai River and urban drainage. The approaches for microbial source tracking employed in this study used PFGE with <i>Enterococcus</i> species as an indicator can be a potential tool to specify the source(s) of fecal pollution and contribute to improved public health in coastal environments.<br>
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Research on gasification rate of organic matter in modeled burial livestock and odor generation
Proceedings of the Annual Conference of Japan Society of Material Cycles and Waste Management 24 ( 0 ) 2013
Language：Japanese Publishing type：Research paper (scientific journal) Publisher：Japan Society of Material Cycles and Waste Management
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Suzuki Yoshihiro, Takeshita Shinichi, Sekito Tomoo, Inagaki Hitone
Japanese Journal of Grassland Science 58 ( 4 ) 269 - 276 2013
Language：Japanese Publishing type：Research paper (scientific journal) Publisher：Japanese Society of Grassland Science
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FURUKAWA Takashi, SHIMAUCHI Hidetaka, SUZUKI Yoshihiro
J. Env. cons. eng 42 ( 10 ) 617 - 624 2013
Language：Japanese Publishing type：Research paper (scientific journal) Publisher：Society of Environmental Conservation Engineering
By applying pulsed-field gel electrophoresis(PFGE)to the aquatic environment as a source tracking method of fecal pollution, the temporal variability of genetic patterns of<i> Enterococcus faecium</i>, as fecal indicator bacterium, was examined. Surface water samples were collected from a fixed point of the Miyazaki municipal river during a two-month period. <i>E. faecium</i> strains were identified and collected from each water sample.Genotypes(PFGE types)of all <i>E. faecium</i> strains were analyzed by PFGE. Then, the similarities between the PFGE types obtained from the first day and those from the other days were compared using dendrogram analysis. The PFGE type of <i>E. faecium</i> was not significantly changed for the initial three days. After the seventh day, the dominant PFGE types were changed. The PFGE types of the 30th and 60th days were not very similar to those of the first day. It was indicated that genetic patterns of <i>E. faecium</i> might change to completely dissimilar patterns in a fixed point of the municipal river. Therefore, it is very important to consider the temporal variability of genetic pattern of fecal indicator bacteria for source tracking of fecal pollution.
DOI： 10.5956/jriet.42.617
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一ツ瀬ダム上流域における長期濁水化に 関与する土砂分布地点と地質構造との関係 Reviewed
村上俊樹, 鈴木祥広, 大石博之, 中尾登志雄
土木学会論文集G（環境） 68 ( 7 ) 251 - 257 2012.12
Language：Japanese Publishing type：Research paper (scientific journal)
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豚ふん尿の熱処理によるメタン発酵能向上に関する研究 Reviewed
土手裕, 関戸知雄, 後藤吉史, 鈴木祥広
土木学会論文集G（環境） 68 ( 7 ) 433 - 451 2012.12
Language：Japanese Publishing type：Research paper (scientific journal)
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Suzuki Y., Kanda N., Furukawa T.
Journal of Environmental Science and Health - Part A Toxic/Hazardous Substances and Environmental Engineering 47 ( 11 ) 1500 - 1505 2012.9
Language：English Publishing type：Research paper (scientific journal) Publisher：Journal of Environmental Science and Health - Part A Toxic/Hazardous Substances and Environmental Engineering
Enterococci such as Enterococcus faecalis and E. faecium are considered as the most suitable indicators of fecal pollution in an aquatic environment, and new methods for Enterococcus determination have been developed, namely, membrane filtration (MF) using membrane-Enterococcus indoxyl-β-D-glucoside agar (mEI) and defined substrate technology (DST) using Enterolert®. This study used PCR analysis to identify E. faecalis and E. faecium among Enterococcus strains in river water isolated using both mEI plates and Enterolert® trays. There was a significantly high correlation between MF and DST in terms of enterococcal counts for river water samples. The combined percentages of E. faecalis and E. faecium with respect to the total number of all strains obtained using mEI plates and Enterolert® trays were approximately 30% and > 30%, respectively. Other than E. faecalis and E. faecium, a large number of Enterococcus species were unspecified in the actual urban river samples. A comparison of the predominance of E. faecalis and E. faecium found that the abundance of a species depended on the sampling river and date. E. faecium is a non-predominant species in intestinal and fecal Enterococci, and it was one of the main Enterococcus species detected in surface water. Copyright © Taylor & Francis Group, LLC.
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置砂施工に用いるダム堆砂の洗浄工程で発生する濁水の簡易凝集処理 Reviewed
鈴木祥広
用水と廃水 54 ( 8 ) 605 - 612 2012.8
Language：Japanese Publishing type：Research paper (scientific journal)
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Monitoring of Fecal Bacteria in a Coastal Recreation Area during Summer Months Reviewed
FURUKAWA Takashi, KAWABATA Hayato, SUZUKI Yoshihiro
J. Env. cons. eng 41 ( 3 ) 138 - 145 2012.3
Language：Japanese Publishing type：Research paper (scientific journal) Publisher：Society of Environmental Conservation Engineering
Fecal coliform (FC)and enterococci(ENT), frequently used as fecal indicators were monitored in the coastal recreation area of Miyazaki, Japan, from June to September 2009. The FC and ENT counts in coastal water were found to range from Below detection limits(BDL)to 6.3× 10<sup>3</sup>CFU/100 mL and from BDL to 5.2× 10<sup>2</sup>CFU/100 mL, respectively. These counts varied depending on the numbers of sampling days and stations, and exceeded the criteria for marine recreation water recommended by the US Environmental Protection Agency during sampling events. Both bacteria showed a significant positive correlation with rainfall (FC:r=0.83, ENT:r=0.99), and a negative correlation with salinity (FC:r=-0.60, ENT :r=-0.75). In the identification test of enterococcal strains using PCR, <I>Enterococcus faecium</I> and <I>Enterococcus faecalis</I> were detected at high frequencies in some stations. Our findings demonstrate that during heavy rains, some stations in the coastal recreation area could be affected by fecal pollution from human and livestock feces with the inflow of inland water.
DOI： 10.5956/jriet.41.138
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ダム底泥に含まれる鉄が海藻ヤツマタモクの生長と増殖に及ぼす効果（共著） Reviewed
鈴木祥広, 濱崎祥大, 荒武久道, 齋藤剛
用水と廃水 54 ( 2 ) 136 - 144 2012.2
Language：Japanese Publishing type：Research paper (scientific journal)
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MURAKAMI Toshiki, SUZUKI Yoshihiro, OISHI Hiroyuki, NAKAO Toshio
PROCEEDINGS OF ENVIRONMENTAL AND SANITARY ENGINEERING RESEARCH 68 ( 7 ) III_251 - III_257 2012
Language：Japanese Publishing type：Research paper (scientific journal) Publisher：Japan Society of Civil Engineers
Through a soil survey, the authors collected soil samples from different strata at locations where landslip had occurred in the upstream area of a dam reservoir suffering from long-term turbidity. And soil specimens that might be responsible for accelerating the turbidity were obtained from the soil samples, using a simple suspension method. The soil specimens were categorized into four risk levels, indicating their degree of turbidity. Further, we prepared a detailed geological block diagram, which specifies different geological structures based on metamorphic grades. As a result, it was found that there was a significant correlation between the distribution of geological structure and the locations where high-risk-level soil samples were collected. This information is useful for determination of the distribution of soil structure at specific locations where there is soil causing turbidity, contributing to effective countermeasures for long-term turbidity in dam reservoirs.
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Effect of thermal treatment of pig manure on methane fermentation
DOTE Yutaka, SEKITO Tomoo, GOTOH Yoshifumi, SUZUKI Yoshihiro
PROCEEDINGS OF ENVIRONMENTAL AND SANITARY ENGINEERING RESEARCH 68 ( 7 ) III_443 - III_451 2012
Language：Japanese Publishing type：Research paper (scientific journal) Publisher：Japan Society of Civil Engineers
Thermal treatment of pig manure followed by batch and continuous methane fermentation was conducted in order to evaluate its effect on fermentation performance. Up to 200°C of thermal treatment, solubilization of VSS proceeded, but transformation of dissolved TOC with high molecule count into VFA was minimal. The high temperature led to retardation of initial gas generation and low gas generation rate. At 250°C, no gas generation occurred. At 150°C, methane generation per input VS with thermal treatment was 1.2 times greater than that without thermal treatment. The thermal treatment of standard pig manure was disadvantageous to net energy recovery. However, it was estimated that thermal treatment of manure with SS concentration of greater than 2.3 times the SS of standard manure increased net energy recovery over that without thermal treatment.
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Mass balance and gas generation from modeled column of livestock bulial site.
Fujiwara Naohiro, Sekito Tomoo, Dote Hiroshi, Suzuki Yoshihiro, Inagaki Hitone, Morita Tetsuo
Proceedings of the Annual Conference of Japan Society of Material Cycles and Waste Management 23 ( 0 ) 2012
Language：Japanese Publishing type：Research paper (scientific journal) Publisher：Japan Society of Material Cycles and Waste Management
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Monitoring of Fecal Bacteria on Aoshima Beach, Miyazaki, Japan Reviewed
FURUKAWA Takashi, KAI Ryusuke, DOTE Yutaka, SUZUKI Yoshihiro
Japan journal of water pollution research 34 ( 12 ) 197 - 201 2011.12
Language：Japanese Publishing type：Research paper (scientific journal) Publisher：Japan Society on Water Environment
Recently, coastal recreation areas have been polluted by pathogenic microorganisms from human and animal feces. In fact, it has been reported that the risk of infection by pathogens is not negligible in coastal areas. Fecal bacteria (e.g., fecal coliforms (FCs) and enterococci (ENTs)) were monitored on Aoshima Beach, Miyazaki, Japan, to understand the contamination by fecal bacteria, indicating the presence of pathogens in coastal recreation areas. Coastal water samples were collected at 5 stations on Aoshima Beach between May and August, 2010. The FC and ENT counts in coastal water were found to range from below detection limits (BDL) to 1.4×10<SUP>3</SUP> CFU·100 mL<SUP>-1</SUP> and from BDL to 4.6×10<SUP>2</SUP> CFU·100 mL<SUP>-1</SUP>, respectively. The monitoring carried out daily between June 23 and July 21 indicated that the concentrations of both fecal bacteria increased during rainfall, exceeding the guideline levels set by U. S. Environmental Protection Agency (i.e., FC, 800 CFU·100 mL<SUP>-1</SUP>; ENT, 104 CFU·100 mL<SUP>-1</SUP>). However, the high fecal bacterial counts decreased to approximately 10 CFU·100 mL<SUP>-1</SUP> within 3 days after the rainfall.
DOI： 10.2965/jswe.34.197
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鶏ふん焼却灰からのリン回収における硫酸除去のためのカルシウム源の評価に関する研究（共著） Reviewed
土手裕, 関戸知雄, 園田忠道, 矢野浩司, 鈴木祥広
土木学会論文集G(環境） 67 ( 7 ) 195 - 202 2011.11
Language：Japanese Publishing type：Research paper (scientific journal)
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Suzuki Yoshihiro, Narimatsu Shogo, Furukawa Takashi, IWAKIRI Akira, MIURA Miho, YAMAMOTO Shogo, KATAYAMA Hiroyuki
Journal of bioscience and bioengineering 112 ( 4 ) 369 - 372 2011.10
Language：English Publishing type：Research paper (scientific journal) Publisher：公益社団法人日本生物工学会
The monitoring of NVs in municipal wastewater by both real-time RT-LAMP and real-time RT-PCR, and the comparison of these two methods with respect to NV detection were carried out. The change in NVs detected by real-time RT-LAMP agreed well with that detected by real-time RT-PCR. In contrast, the correlation between the copy number determined by real-time RT-PCR and the threshold time (Tt) determined by real-time RT-LAMP obtained during monitoring was not significant (0.1<p) for both NV-GI and NV-GII.
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Furukawa T., Takahashi H., Yoshida T., Suzuki Y.
Microbes and Environments 26 ( 2 ) 181 - 183 2011.6
Language：Japanese Publishing type：Research paper (scientific journal) Publisher：Microbes and Environments
PFGE has potential applications in the source tracking of fecal pollution in aquatic environments. We tried to distinguish the genotypes of Enterococcus faecium collected from fecal-contaminated water using PFGE. Well identified 115 strains of E. faecium were classified into 25 PFGE patterns, and characteristics distinctive to each genotype were recognized. Analysis of the characteristics of genotypes using PFGE can be used to track source of fecal pollution.
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Application of PFGE to source tracking of fecal pollution in coastal recreation area: A case study in Aoshima Beach, Japan"jointly worked" Reviewed
Furukawa T, Yoshida T, Suzuki Y
Journal of Applied Microbiology 110 688 - 696 2011.5
Language：English Publishing type：Research paper (scientific journal)
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Suzuki Y., Suzuki T., Kono T., Mekata T., Sakai M., Itami T.
Journal of Virological Methods 173 ( 2 ) 227 - 232 2011.5
Language：English Publishing type：Research paper (scientific journal) Publisher：Journal of Virological Methods
The white spot disease virus (WSDV), which is most virulent in shrimp, is a cause of serious damage in the shrimp production industry. However, it is difficult to track the infection route and behaviour of WSDV in shrimp farms because it is present at extremely low concentrations in culture sea water. In this study, the concentration of WSDV in sea water foam was examined using dispersed bubbles and milk casein as a surface-active protein. WSDV concentrations were assessed using real-time PCR. When ferric colloid adsorption was performed prior to foam separation, WSDV was effectively removed from sea water and concentrated in the generated foam within 5. min. The removal efficiency was greater than 90% at the optimum iron and casein concentrations of 1. mg Fe/l and 1. mg/l, respectively. Furthermore, to analyse the dissolution of the collected ferric colloid, the WSDV concentration in the colloid-dissolved solution was set to be 200-fold higher than that found in raw water. This represents a novel method of concentrating WSDV for its detection in sea water using a combination of ferric colloid adsorption and foam separation that is easy to perform, rapid and efficient. © 2011 Elsevier B.V.
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Genotypic Characterization of Enterococci Collected from a Coastal Area Using PFGE Reviewed
FURUKAWA Takashi, YOSHIDA Terutoyo, SUZUKI Yoshihiro
J. Env. cons. eng 40 ( 3 ) 138 - 143 2011.3
Language：Japanese Publishing type：Research paper (scientific journal) Publisher：Society of Environmental Conservation Engineering
Development of microbial source tracking (MST) is crucial to ensure public health and bacteriological safety in coastal areas. In this study, pulsed-field gel electrophoresis (PFGE) , utilized for pollution source tracking of hospital infections, was applied to the aquatic environment as a MST method. <I>Enterococcus faecium</I> and <I>Entecococcus faecalis</I>, fecal indicator bacterias, were isolated and identified from a port area, and the genotype was analyzed by PFGE. A total of 230 enterococcal strains were isolated by PFGE, and forty strains were identified as <I>E. faecium</I> using both PCR and the Api 20 Strep test. Dendrogram analysis of the PFGE types revealed that all the 40 <I>E. faecium</I> strains can be classified separately into 7 different groups at a 0.7 similarity level. The genotypic characterization of <I>E. faecium</I> from the coastal port area revealed diverse types. It is suggested that PFGE can be used to differentiate and characterize fecal pollution indicating bacteria by applying it to the aquatic environment, as well as provide detailed information to specify the pollution source.
DOI： 10.5956/jriet.40.138
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マイクロプレートを用いたバイオアッセイによる宮崎県五ヶ瀬川水系の藻類増殖制限物質の検索 Reviewed
鈴木祥広, 黒澤津翔, 金丸祐加, 高見徹, 鬼束幸樹
用水と廃水 53 ( 2 ) 134 - 141 2011.2
Language：Japanese Publishing type：Research paper (scientific journal)
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Fall J., Chakraborty G., Kono T., Maeda M., Suzuki Y., Itami T., Sakai M.
Fisheries Science 77 ( 1 ) 129 - 134 2011
Language：English Publishing type：Research paper (scientific journal) Publisher：Fisheries Science
Vibrio nigripulchritudo is considered one of the major pathogens threatening shrimp aquaculture. In this study, we developed a novel and highly specific quantitative loop-mediated isothermal amplification (Q-LAMP) assay. A set of four specific primers were designed targeting the V. nigripulchritudo intergenic spacer region. The reaction time and temperature were optimized for 60 min at 63°C. Quantitative analysis was then performed by measuring the turbidity of the reaction solution using a real-time turbidimeter, allowing for quantification of the initial DNA concentration with a sensitivity of 10 2 copy numbers equivalent to 2.3 colony forming units/ml or 0.3 fg/μl. The LAMP assay was able to specifically detect two representative strains of V. nigripulchritudo, whereas other Vibrio and non-Vibrio species were not amplified. A standard curve was generated for V. nigripulchritudo by plotting the threshold time (T t ) versus the log of bacterial number. A high correlation coefficient (R 2 = 0.9749) was observed for the Q-LAMP reaction. In conclusion, Q-LAMP assay is a sensitive, rapid, and simple tool that can be used for the detection and quantification of V. nigripulchritudo in shrimp, thereby facilitating surveillance of vibriosis infection. © 2010 The Japanese Society of Fisheries Science.
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Study on characteristics of early phase leachate from simulated carcasses burial site
sekito tomoo, dote yutaka, morita tetsuo, inagaki hitone, suzuki yoshihiro
Proceedings of the Annual Conference of Japan Society of Material Cycles and Waste Management 22 ( 0 ) 199 - 199 2011
Language：Japanese Publishing type：Research paper (scientific journal) Publisher：Japan Society of Material Cycles and Waste Management
Recently mass carcasses burial has been occurred in order to prevent further spread of the animal disease such as foot and mouth disease and bird flu. It is important to estimate environmental contaminations from the burial sites. In this study, leachate characteristics from carcasses burial site were investigated by laboratory scale column test. In this study, rats were used as modeled carcasses. From the analysis of the leachate, significant high concentrations of COD (20,000-40,000 mg/L) and NH3-N (5,000-10,000 mg/L) in the early period of experiment were determined. The generation of initial leachate from a column with saw dust as a part of soil could be delayed. Further study for kinetics of organic degradation and material balance is necessary.
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バッチプラントでの硫酸を用いた鶏ふん焼却灰からのリン回収に関する研究 Reviewed
土手裕, 関戸知雄, 太田靖子, 鈴木祥広
環境工学研究論文集 47 451 - 458 2010.11
Language：Japanese Publishing type：Research paper (scientific journal)
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物理・化学的性状解析によるダム貯水池の長期濁水化の原因となる難沈降性粒子の発生源追跡手法の提案 Reviewed
村上俊樹, 鈴木祥広, 瀬崎満弘, 伊藤健一, 中尾登志雄
環境工学研究論文集 47 199 - 206 2010.11
Language：Japanese Publishing type：Research paper (scientific journal)
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沿岸レクリエーションエリアにおけるふん便性細菌汚染の調査 Reviewed
古川 隼士, 川畑 勇人, 鈴木 祥広
環境技術 39 ( 8 ) 493 - 499 2010.8
Language：Japanese Publishing type：Research paper (scientific journal) Publisher：Society of Environmental Conservation Engineering
本研究では，宮崎県内の沿岸域における細菌学的調査を実施した．沿岸水試料のふん便性大腸菌群（FC）とふん便性連鎖球菌（FS）は，それぞれ０～1.9×10<sup>3</sup>CFU/100mLと０～2.0×10<sup>3</sup>CFU/100mLで検出され，浜砂試料では，それぞれ０～3.0×10<sup>3</sup>CFU/100g-dryと０～1.4×10<sup>4</sup>CFU/100g-dryで検出された．海水浴場やサーフィンエリアのレクリエーションエリアでは，降雨による影響が考えられる６月と10月の調査日を除けば，晴天時では両細菌ともに100CFU/100mL以下であった．各細菌数は，季節ごと，地点ごとにおいて変動が大きかった．
DOI： 10.5956/jriet.39.493
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Spawning of Kuruma Shrimp in a Closed Recirculating Aquaculture System after Eyestalk Ablation Reviewed
SUZUKI Yoshihiro, SAGISU Yuji, SUZUKI Takahiko, MEKATA Thoru, KONO Tomoya, KOSHIO Shunsuke, SAKAI Masahiro, ITAMI Toshiaki
58 ( 2 ) 161 - 166 2010.6
Language：Japanese Publishing type：Research paper (scientific journal)
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Behavior of Fecal Bacteria in a Coastal Urban River
FURUKAWA Takashi, TANAKA Akihiko, YOSHIDA Terutovo, SUZUKI Yoshihiro
J. Env. cons. eng 39 ( 3 ) 170 - 176 2010.3
Language：Japanese Publishing type：Research paper (scientific journal) Publisher：Society of Environmental Conservation Engineering
DOI： 10.5956/jriet.39.170
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Biota of fecal bacteria concentrated in stable foam formed along water's edge in coastal zones Reviewed
Furukawa T., Yoshida T., Suzuki Y.
Bubble Science, Engineering and Technology 2 ( 1 ) 25 - 30 2010.3
Language：English Publishing type：Research paper (scientific journal) Publisher：Bubble Science, Engineering and Technology
Since the coastal zone plays an important role in recreation, humans might be directly or indirectly exposed to pathogenic bacteria. Along the water's edge at the coast, stable yellowish brown foam generated by breaking waves is observed frequently. We examined the foam, and determined the fecal bacteria count in coastal water, sand and the foam on the Miyazaki coast, Japan. Fecal coliform and fecal streptococcus counts in the foam were markedly higher than those in the coastal water and sand. Furthermore, the concentration of dissolved organic carbon in the foam was much higher than that in the coastal water. We concluded that the fecal bacteria were concentrated in the foam formed by bubbles generated in the water and that the dissolved organic substances exhibit surface activity. In addition, the main species of fecal streptococcus in the foam was enterococcus faecium, which is often used as an indicator of fecal pollution. © 2010 W. S. Maney & Son Ltd.
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河川水と海水のバッチ式混合実験におけるエストロゲンの挙動（共著）
古川隼士, 鈴木祥広
宮崎大学工学部紀要 2010.3
Language：Japanese Publishing type：Research paper (bulletin of university, research institution)
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海水との混合による都市河川水中のふん便性細菌の挙動に関する基礎的検討.共著） Reviewed
古川隼士, 田中昭彦, 吉田照豊, 鈴木祥広
環境技術 39 ( 3 ) 170 - 176 2010.3
Language：Japanese Publishing type：Research paper (scientific journal)
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Genotypic analysis of enterococci collected from a coastal sone by pulsed-field gel electrophoresis (PFGE) for application of microbial source tracking."jointly worked" Reviewed
Furukawa, T., Yoshida, T. and Suzuki, Y.
ASPIRE2009 65 - 65 2009.10
Language：English Publishing type：Research paper (international conference proceedings)
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A simple non-enzymatic method for the preparation of white spot syndrome virus (WSSV) DNA from the haemolymph of Marsupenaeus japonicus using FTA matrix cards."jointly worked" Reviewed
Sudhakaran, R., Mekata, T., Kono, T., Supamattaya, K., Linh, N.T.H., Suzuki, Y., Sakai, M. and Itami, T.
Journal of Fish Diseases 32 611 - 617 2009.10
Language：English Publishing type：Research paper (scientific journal)
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Residual of 17β-estradiol in digestion liquid generated from a biogas plant using livestock waste
Suzuki Y., Kubota A., Furukawa T., Sugamoto K., Asano Y., Takahashi H., Sekito T., Dote Y., Sugimoto Y.
Journal of Hazardous Materials 165 ( 1-3 ) 677 - 682 2009.6
Language：English Publishing type：Research paper (scientific journal) Publisher：Journal of Hazardous Materials
A biogas plant using livestock waste in which a methane fermentation process is applied is a useful facility for generating energy. The digestion liquid generated from the biogas plant as a residue has high potential for use as a crop fertilizer. However, high-density estrogens such as 17β-estradiol (E2) are included in livestock waste, and there is little information on the behavior of E2 in the digestion liquid. In this study, a survey of E2 concentration at each process in a biogas plant using livestock waste was carried out. In addition, the efficiencies of E2 removal from the digestion liquid by activated carbon adsorption and soil infiltration were examined. The total concentration of E2 in raw livestock waste was reduced to 2 μg/l after treatment, and the removal efficiency of E2 was about 80% for the plant. The methane fermentation process is important not only for the generation of methane but also for the removal of E2. The proportion of E2 conjugates comprising the total E2 concentration was 10% or less in all treated samples. In the plant, there is no likelihood of an increase in estrogen activity by the cleaving of E2 conjugates. By carrying out activated carbon adsorption to remove E2 from the digestion liquid, a large portion of E2 was removed from the digestion liquid, but an E2 concentration of 0.5 μg/l still remained in the treated digestion liquid. In contrast, it was possible to purify the digestion liquid to an E2 concentration of less than 0.002-0.011 μg/l by soil infiltration. It is thus possible to utilize the digestion liquid as a fertilizer without causing aquatic environmental pollution, but factors such as application rate, soil characteristics, and the E2 concentration of digestion liquid should be considered first. © 2008 Elsevier B.V. All rights reserved.
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宮崎県小丸川水系のダム堆積土砂に含まれる難沈降粒子の物理・化学的性状 Reviewed
鈴木祥広, 出口近士, 関戸知雄, 塩盛弘一郎, 杉尾哲
土木学会論文集 65 ( 1 ) 16 - 25 2009.2
Language：Japanese Publishing type：Research paper (scientific journal)
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Suzuki Y., Narimatsu S., Furukawa T., Mekata T., Kono T., Sakai M., Itami T., Katayama H.
Separation Science and Technology 44 ( 3 ) 569 - 584 2009.2
Language：English Publishing type：Research paper (scientific journal) Publisher：Separation Science and Technology
To prevent the spread of acute gastroenteritis, which prevails during winter and is called the winter vomiting disease, it is necessary to develop a technology for the detection and removal of noroviruses (NVs) from contaminated water. In this study, the removal from municipal wastewater and concentration in foam of NVs using dispersed bubbles and milk casein as a surface-active protein were examined. Real-time reverse transcription loop-mediated isothermal amplification (RT-LAMP) as a new nucleic acid amplification method was used for NV detection. Although NV-GII was detected in two wastewater samples, NV-GI was not detected. By foam separation using dispersed bubbles, NV-GII was removed from wastewater and concentrated into the generated foam. The concentration of NV-GII in the collapsed foam water was more than approximately 8-fold higher than that in the wastewater. Because the generated foam can be analyzed by real-time RT-LAMP, it is possible to sensitively monitor NV pollution in aqueous environments. Here, we show for the first time the removal from aqueous solution and concentration of NVs in foam using dispersed bubbles and a surface-active substance.
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Mekata T., Sudhakaran R., Kono T., U-taynapun K., Supamattaya K., Suzuki Y., Sakai M., Itami T.
Journal of Virological Methods 162 ( 1-2 ) 81 - 87 2009.1
Language：English Publishing type：Research paper (scientific journal) Publisher：Journal of Virological Methods
A real-time reverse transcription loop-mediated isothermal amplification (real-time RT-LAMP) method was applied for detecting the replicase polyprotein-encoding gene of yellow head virus (YHV) in shrimp, Penaeus monodon. It is a novel, gene-specific assay that amplifies nucleic acid with high specificity, sensitivity and rapidity under isothermal conditions using a set of six specially designed primers that recognize eight distinct sequences of the target gene. This method works with even low copies of DNA and is based on magnesium pyrophosphate turbidity detection by an inexpensive photometer for quantitative analysis. A user-friendly protocol was developed with optimal conditions standardized at 63 °C for 60 min. With this protocol, the assay sensitivity was 10 times higher than the widely used YHV nested RT-PCR system. Cross-reactivity analysis using other shrimp virus DNA/cDNA and YHV-negative shrimp demonstrated high specificity of the assay. The real-time RT-LAMP method was performed also for an internal control gene, EF-1α, to compare with the expressions of the YHV gene in different organs of infected shrimp, and the resulting standard curves showed high correlation coefficient values. These results suggest that this assay is applicable widely as a new quantitative detection method in the pursuit of YHV-free shrimp culture. © 2009 Elsevier B.V. All rights reserved.
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SUZUKI Yoshihiro, DEGUCHI Chikashi, SEKITO Tomoo, SHIOMORI Koichiro, SUGIO Satoru
Journal of Japan Society of Civil Engineers, Ser. G (Environmental Research) 65 ( 1 ) 16 - 25 2009
Language：Japanese Publishing type：Research paper (scientific journal) Publisher：Japan Society of Civil Engineers
The characteristics of fine particles such as grain size and mineral composition contained into the sediment in three dam reservoirs (Dokawa, Matsuo and Kawaharu dams) along river Omaru in Miyazaki were investigated. The size of particles, which were difficult to settle as the cause factor of the turbid dam water for a long period, were average 2μm, and the shape was plane. By examining from the particles composition, the origin of fine particles in Matsuo and Kawaharu dams was identical with the fine particles in sediment of Dokawa dam. The content of fine particles was 10 mg/g-dry sediment and the settling velocity was markedly low (2 mm/hr). It was indicated that the clarification of suspension water in the dam reseroir containing the large amount of fine particles would be difficult by gravity sedimentation.
DOI： 10.2208/jscejg.65.16
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SUZUKI Yoshihiro, SUZUKI Takahiko, SAGISHU Yuji, MEKATA Thoru, KONO Tomoya, KOSHIO Shunsuke, YOKOYAMA Saichiro, SAKAI Masahiro, ITAMI Toshiaki
56 ( 4 ) 479 - 485 2008.12
Language：Japanese Publishing type：Research paper (scientific journal)
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Thimdee W., Deein G., Nakayama N., Suzuki Y., Matsunaga K.
Wetlands Ecology and Management 16 ( 6 ) 463 - 470 2008.12
Language：English Publishing type：Research paper (scientific journal) Publisher：Wetlands Ecology and Management
Stable carbon and nitrogen isotope ratios were used to elucidate primary carbon sources and trophic relationships of the fish and shrimp community in the Klong Ngao mangrove ecosystem, southern Thailand. There were no significant differences in isotopic compositions of biota between mangrove and offshore sites (Welch-Aspin test). The δ 15 N values of eight fish species and two shrimp species at both sites were also not significantly different by the test, meaning that at both sites they feed on the same diets due to the discharge of large quantities of mangrove sediments. The δ 15 N isotopic enrichment of consumers suggested that there are four trophic levels in the Klong Ngao food web, with at least two fish species capable of switching feeding strategies and thus altering their apparent trophic positions. Phytoplankton culture experiments indicated that mangrove-derived sediments could play an important role in stimulating phytoplankton growth for low turbidity offshore areas, thus providing an alternate food source. The isotopic associations among sources and consumers indicated that mangroves were the major carbon source supporting aquatic food webs in the Klong Ngao ecosystem. © 2008 Springer Science+Business Media B.V.
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蛍光分析による大淀川河川水の水質評価 Reviewed
海賀信好, 鈴木祥広, 高橋基之, 世良保美
用水と廃水 50 ( 11 ) 941 - 949 2008.11
Language：Japanese Publishing type：Research paper (scientific journal)
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PHOSPHORUS RECOVERY FROM LIVESTOCK MANURE INCINERATION ASH AND PRODUCT CHARACTERISTICS Reviewed
SEKITO Tomoo, DOTE Yutaka, KAIKAKE Katsuya, MASUDA Sumio, SUZUKI Yoshihiro
Journal of Japan Society of Civil Engineers, Ser. G (Environmental Research) 64 ( 2 ) 88 - 95 2008.8
Language：Japanese Publishing type：Research paper (scientific journal) Publisher：Japan Society of Civil Engineers
Livestock animal manure incineration ash contains phosphorus, which has fertilizer effect and is exhaustible resource. This paper describes the technique of phosphorus recovery from livestock animal manure incineration ash. Phosphorus concentration and chemical compound in recovered product were determined. Phosphorus was extracted from ash with 1.5M HCl solution and the products contained phosphorus was recovered as precipitate by alkali addition to the acid solution. Citric acid soluble phosphate content in the recovered product is 150 mg/g, which is comparable to commercially available calcined phosphate fertilizer. Phosphorus existed in the recovered product as calcium hydrogen phosphate dihydrate (DCPD) or hydroxy apatite (HAP). The ratio of DCPD and HAP in the products was depended on pH of the precipitation.
DOI： 10.2208/jscejg.64.88
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Suzuki Y., Hanagasaki N., Furukawa T., Yoshida T.
Journal of Bioscience and Bioengineering 105 ( 4 ) 383 - 388 2008.4
Language：English Publishing type：Research paper (scientific journal) Publisher：Journal of Bioscience and Bioengineering
The removal of bacteria from rearing water and washing water in aquaculture systems, aquariums and fishing port facilities is the most important means of diminishing the risk of fish diseases, improving public health and ensuring high food quality. However, there are few methods of bacterial elimination, e.g., disinfection. Thus, it is necessary to develop a technology for bacterial removal from coastal seawater. In this study, the removal efficiency for several groups of bacteria by foam separation using dispersed bubbles and surface-active substances was determined using both batch equipment and a continuous-flow unit. By batch processing with only 1 mg/l milk casein added as a surface-active substance and by supplying bubbles, viable bacteria, enterococci, Vibrio, and Salmonella-like bacteria were removed effectively at removal efficiencies of 80% or greater. In addition, suspended solids were also removed from coastal seawater. However, fecal coliforms were difficult to remove by foam separation. The removal efficiency for viable bacteria was greater than 70% using a continuous system. Bacteria were concentrated in a very small amount of generated foam and removed from the water. The foam separation using dispersed bubbles and surface-active substances is a feasible convenient technology for seawater purification as a treatment prior to membrane filtration or ultraviolet irradiation. © 2008 The Society for Biotechnology, Japan.
DOI： 10.1263/jbb.105.383
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河口域の環境調査における溶存酸素測定の留意点 Reviewed
鈴木祥広, 原村優子, 古川隼士
用水と廃水 49 ( 11 ) 951 - 956 2007.11
Language：Japanese Publishing type：Research paper (scientific journal)
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Monitoring of Bacteria in Aoshima Fishing Port, Japan Reviewed
SUZUKI Yoshihiro, HANAGASAKI Nobuaki, TAKAHASHI Hironori, FURUKAWA Takashi, YOSHIDA Terutoyo
Japan journal of water pollution research 30 ( 10 ) 597 - 601 2007.10
Language：Japanese Publishing type：Research paper (scientific journal) Publisher：Japan Society on Water Environment
The proper management of water quality in fishing ports handling seafood is necessary for ensuring food quality and public health. In this study, the hygienic conditions at Aoshima fishing port (Miyazaki, Japan) and surrounding coastal areas were investigated. In water samples obtained from inner sites of the port using a lift pump, coliform counts and fecal streptococcus counts varied seasonally from 10 to 10<SUP>4</SUP> MPN·100m<I>l</I><SUP>-1</SUP> and from 0 to 10<SUP>2</SUP> MPN·100m<I>l</I><SUP>-1</SUP>, respectively. In water samples from an estuary located adjacent to the port, coliform counts and fecal streptococcus counts were1 to 2 orders of magnitude higher that those of water samples from the fishing port. Coliform counts obtained by the MPN method were significantly higher than fecal streptococcus counts and fecal coliform counts obtained by the membrane filter method. Fecal streptococcus counts and fecal coliform counts corresponded to 2% and 3% of coliform counts, respectively. There was an inverse correlation between salinity and coliform counts, and coliforms seemed to be diluted with seawater. Fecal streptococcus counts showed a lower correlation with not only salinity but also turbidity, suggesting that sedimentation and resuspension affect the fecal streptococcus population dynamics in the estuary near the port.
DOI： 10.2965/jswe.30.597
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家畜ふん焼却灰からのリン回収方法の開発と回収物性状 Reviewed
関戸知雄, 土手裕, 勝也, 貝., 増田純雄, 鈴木祥広
土木学会論文集Ｇ 62 ( 2 ) 2007.9
Language：Japanese Publishing type：Research paper (scientific journal)
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Fate of natural estrogens in batch mixing experiments using municipal sewage and activated sludge Reviewed
Suzuki Y., Maruyama T.
Water Research 40 ( 5 ) 1061 - 1069 2006.3
Language：English Publishing type：Research paper (scientific journal) Publisher：Water Research
Since natural estrogens such as 17β-estradiol (E2) and estrone (E1) are excreted daily by humans, E2 and E1, which are classified as inevitable endocrine-disrupting chemicals, are always present in sewage wastewater. For several years, the monitoring and removal of natural estrogens at sewage treatment plants have been examined by many investigators. However, little is known regarding the exact behavior of estrogens in actual sewage when in contact with activated sludge. In this study, the fate of E2 and E1 as a result of adsorption and decomposition in batch mixing experiments using municipal wastewater and activated sludge collected from an actual municipal sewage treatment plant was investigated. Estrogen concentrations were determined using an enzyme-linked immunosorbent assay (ELISA) kit. E2 and E1 in sewage were removed from the liquid phase in contact with activated sludge, and E2 and E1 adsorbed on the sludge were decomposed in 4 h. Significant changes in the adsorption and decomposition of E2 and E1 on the sludge were not observed at low temperatures or when different sludge samples were used such as those acclimatized to low-loading and high-loading conditions. In contrast, the processes leading to the removal of estrogens, such as the adsorption and decomposition of estrogens in contact with activated sludge, were inactivated by sterilizing the sludge. Natural estrogens adsorb onto the activated sludge, and are therefore easy to be biodegraded. In a biological reaction process, therefore, the estrogens will be rapidly removed at the initial stage, when the sewage is satisfactorily mixed with the sludge. © 2006 Elsevier Ltd. All rights reserved.
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Removal of di-2-ethylhexyl phthalate (DEHP) from River Water Using Dispersed Bubbles Reviewed
SUZUKI Yoshihiro, ANDOH Yasuhiro, MARUYAMA Toshiroh, MITSUYAMA Munehito, SHIMOTSU Yoshihiro, GOMI Kenji, MORI Hirokazu, KUNIKANE Shoichi
Japan journal of water pollution research 29 ( 1 ) 29 - 35 2006.1
Language：Japanese Publishing type：Research paper (scientific journal) Publisher：Japan Society on Water Environment
In some water treatment plants, floating foam scum, which concentrates micropollutants such as di-2-ethylhexyl phthalate (DEHP), is a serious problem. We assumed the mechanism of foam scum generation to be as follows: DEHP in water adsorbs onto the gas-liquid interface of bubbles and accumulates on the water surface by floating bubbles, and then is concentrated in foam generated by surface-active matter in raw river water. To apply this mechanism, in this study, the removal of DEPH from river water by generating foam using dispersed bubbles was investigated. When river water passed through a foam generator installed in a strong aerator, foam was continuously generated on the water surface and separated as collapsed-foam water. This collapsed-foam water was yellow-brown, and contained high amounts of suspended solids and colloids. However, the amount of collapsed-foam water generated was very small, less than 1% of the total flow volume. In comparison with suspended solids and dissolved organic matters, DEHP was highly concentrated in the collapsed-foam water. The removal efficiencies of DEHP ranged from 7% to 63% using the foam generator. The use of a simple process involving only intensive aeration and foam collection resulted in a high removal efficiency for hydrophobic micropollutants, such as DEHP, which accumulated in the gas-liquid interface from raw tap water.
DOI： 10.2965/jswe.29.29
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都市下水の高速高度処理システムにおけるエストロゲンの挙動 Reviewed
鈴木祥広，平良浩保，丸山俊朗
環境工学研究論文集 42 245 - 252 2005.12
Language：Japanese Publishing type：Research paper (scientific journal)
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Removal of emulsified oil from water by coagulation and foam separation Reviewed
Suzuki Y., Maruyama T.
Separation Science and Technology 40 ( 16 ) 3407 - 3418 2005.12
Language：English Publishing type：Research paper (scientific journal) Publisher：Separation Science and Technology
A new method of emulsified oil separation for oily wastewater incorporating simple operation and shortened treatment time is necessary for improved wastewater treatment in some manufacturing plants. In the present study, the removal of emulsified oil from water by coagulation and foam separation using poly aluminum chloride (PAC) and milk casein was examined. By adding casein before the foam separation process, the oil removal was dramatically improved. By using surfactant (LAS) as a frother, the dosage of casein was drastically reduced. Furthermore, for processing actual oily water, LAS was unnecessary because a sufficient amount of surfactants for foaming was included in the wastewater. For treatment of the actual oily wastewater collected from a steel manufacturing plant, the optimum condition for PAC and casein was 30 mg-Al/L and 10 mg/L, respectively, and the oil concentration decreased from 170 mg/L to 2.2 mg/L. After examining several types of oily wastewater, 96-99% of oil removal efficiency was obtained by adjusting the dosages of PAC and casein. Coagulation and foam separation using casein has shown a high potential as an alternative method to dissolved air flotation (DAF) for processing emulsified oil water.
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沿岸環境調査における底質CODの測定 Reviewed
鈴木祥広，原村優子，中村孝洋，丸山俊朗
用水と廃水 47 ( 11 ) 65 - 69 2005.11
Language：Japanese Publishing type：Research paper (scientific journal)
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Removal of heavy metals from aqueous solution by nonliving Ulva seaweed as biosorbent Reviewed
Suzuki Y., Kametani T., Maruyama T.
Water Research 39 ( 9 ) 1803 - 1808 2005.5
Language：English Publishing type：Research paper (scientific journal) Publisher：Water Research
The growth of dense green seaweed mats of Ulva spp. is an increasing problem in estuaries and coasts worldwide. The enormous amount of Ulva biomass thus becomes a troublesome waste disposal problem. On the other hand, it has been revealed that nonliving seaweed biomass, particularly brown seaweeds, has a high capacity for assimilating heavy metals. In this study, the possibility of using Ulva seaweed biomass as a biosorbent for the removal of heavy metals was examined. After processing, the biomass material was very easy to separate from the aqueous solution using a mesh. The sorption capacity of Cd on Ulva biomass increased upon pretreatment with alkali solution. The outstanding function of the biosorbent was demonstrated at around pH 8. On the basis of the Langmuir isotherms of Cd, Zn and Cu using the alkali-pretreated biomass, the parameters q m and b were determined to be within the narrow range of 60-90 mg/g and 0.03-0.04 L/mg, respectively, for each metal. Given the q m and b values, Ulva seaweed is a good biosorbent material for removing heavy metals. In an experiment using artificial wastewater containing Cd, Zn, Cu, Cr and Ni, it was possible to remove each metal simultaneously using Ulva biomass. Adsorption by Ulva biomass is effective for the removal of heavy metals from wastewater. © 2005 Elsevier Ltd. All rights reserved.
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浄化槽におけるエストロゲンの実態調査 Reviewed
鈴木祥広，平良浩保，満山宗人，下津義博，丸山俊朗
用水と廃水 47 ( 3 ) 63 - 69 2005.3
Language：Japanese Publishing type：Research paper (scientific journal)
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Behavior of natural estrogens in high-rate advanced treatment system
SUZUKI Yoshihiro, TAIRA Hiroyasu, MARUYAMA Toshiroh
Doboku Gakkai Ronbunshuu G 42 245 - 252 2005
Language：Japanese Publishing type：Research paper (scientific journal) Publisher：Japan Society of Civil Engineers
The behavior of the highly potential endocrine disrupters 17β-estradiol (E2) and estrone (E1) was investigated in an air-fluidized-bed biofilm reactor system, which consisted of an oxidation reactor, a nitrification reactor and a denitrification reactor using a polypropylene carrier, for advanced sewage treatment. E2 and E1 concentrations were determined using an enzyme-linked immunosorbent assay (ELISA) kit. The effluent concentrations of total organic carbon and total nitrogen from the denitrification reactor were maintained at 8mg-C/L and 5mg-N/L, respectively, under a total hydraulic retention time of 4 hr in the biological process. The removal of nitrogen as advanced sewage treatment was achieved by the system. However, the removal efficiencies of E2 and E1 in the biological process were less than 70% and 40%, respectively. Over three weeks, the average estrogen concentrations in the effluent of the denitrification reactor were 2.6ng/L for E2 and 28.2ng/L for El. Although the system successfully achieved advanced treatment, the removal efficiency of natural estrogens was lower than that for a conventional activated sludge plant. The advanced treatment of municipal sewage must be promoted to improve the aquatic environment, while it is necessary to take into account the fate of estrogens in the process.
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Removal of Suspended Solids by Coagulation and Foam Separation using Milk Casein
MARUYAMA Toshiro, SUZUKI Yoshihiro
Japanese journal of multiphase flow 18 ( 4 ) 314 - 323 2004.12
Language：Japanese Publishing type：Research paper (scientific journal)
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Nutrient Recovery from Fish Culture Water Using Seaweed Biofilter
SUZUKI Yoshihiro, KAMETANI Takuji, MARUYAMA Toshiroh
Journal of Japan Society on Water Environment 27 ( 12 ) 817 - 824 2004.12
Language：Japanese Publishing type：Research paper (scientific journal) Publisher：Japan Society on Water Environment
Nutrient recovery from fish culture water using a seaweed biofilter was investigated. The green alga Ulva onoi was selected for use as a seaweed biomass. The load capacity of ulva per day derived from nitrate (NO3-N) uptake was 0.9mg-N·g-wet-1·d-1. A closed recirculating aquaculture system consisting of a fish tank, an intensive aeration unit, a nitrification unit and a seaweed biofilter tank was constructed. The required amount of seaweed biomass as determined from feed quantity and load capacity was provided into the seaweed biofilter tank, and fish (Oreochromis mossambicus) were cultured in the system. NO3-N was fixed in the seaweed biomass throughout the experimental period, and did not accumulate in the culture water. The concentrations of ammonium and nitrite were maintained at very low levels of less than 0.15mg-N·l-1. In addition, the survival rate of the cultured fish was 100%, and the ulva in the seaweed biofilter grew well throughout the experimental period. Each process proceeded smoothly, and the aquaculture system was property maintained. As a result of the nitrogen mass balance in the culture, approximately 70% of all the nitrogen excreted by the fish was fixed by the ulva. For an aquaculture system, a seaweed biofilter is a useful water treatment device for achieving both nutrient removal and seaweed production with low maintenance.
DOI： 10.2965/jswe.27.817
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アオサを利用した海藻バイオフィルターによる魚類飼育水からの栄養塩回収 Reviewed
鈴木祥広，亀谷卓司，丸山俊朗
水環境学会誌 27 ( 12 ) 817 - 824 2004.12
Language：Japanese Publishing type：Research paper (scientific journal)
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界面活性タンパク質を用いた泡沫分離法による海水からの細菌除去 Reviewed
鈴木祥広，花ヶ崎宣昌，吉田照豊，丸山俊朗
環境工学研究論文集 41 147 - 153 2004.12
Language：Japanese Publishing type：Research paper (scientific journal)
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TAKEUCHI Yuzo, ISHITOKU Hiroyuki, MARUYAMA Toshiro, SUZUKI Yukihiro, TSUZUKI Eiji, ENDOU Makoto
Environmental conservation engineering 33 ( 9 ) 699 - 705 2004.9
Language：Japanese Publishing type：Research paper (scientific journal)
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高効率生産と負荷削減を目指した閉鎖循環式養殖システムの開発 Reviewed
鈴木祥広，丸山俊朗，谷口博紀，亀谷卓司，吉田照豊
用水と廃水 46 ( 9 ) 48 - 58 2004.9
Language：Japanese Publishing type：Research paper (scientific journal)
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閉鎖循環式高密度魚類養殖のための泡沫分離・硝化脱窒システムの開発
丸山 俊朗, 鈴木 祥広
水環境学会誌 = Journal of Japan Society on Water Environment 27 ( 8 ) 2004.8
Language：Japanese Publishing type：Research paper (scientific journal)
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界面活性タンパク質を用いた泡沫分離法による海水からの細菌除去
鈴木 祥広, 花ヶ崎 宣昌, 吉田 照豊, 丸山 俊朗
環境工学研究論文集 41 147 - 153 2004
Language：Japanese Publishing type：Research paper (scientific journal) Publisher：Japan Society of Civil Engineers
The removal of bacteria from rearing seawater of fish or using seawater in fishing port is important from the viewpoint of the reduction of infection risk and hygienics of public health. It is necessary to develop seawater purification technology for the improvement of hygienic conditions on the coastal environment. In this study, the removal of suspended bacteria <I>Enterococcus faecalis</I> from seawater by foam separation using several kinds of surface-active proteins as a chemical agent was examined. The removal efficiency of enterococcus was extremely low by foam separation using each protein without coagulation, because these surface-active materials did not function as a collector. When processing by foam separation with coagulation as a pretreatment, however, proteins such as milk casein and fish mucus showed the greatest capability of suspended bacteria. For treatment of seawater containing enterococcus (10<SUP>7</SUP>CFU/mL), the removal efficiency of counts number was over 99% with the small dosages of iron coagulant (FeCl<SUB>3</SUB>) lmg-Fe/L and casein lmg/L. Foam separation using surface-active protein with coagulation process has a high potential as a new method for removing bacteria from seawater.
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Suzuki Y., Maruyama T., Numata H., Sato H., Asakawa M.
Aquacultural Engineering 29 ( 3-4 ) 165 - 182 2003.12
Language：English Publishing type：Research paper (scientific journal) Publisher：Aquacultural Engineering
The development of a closed recirculating aquaculture system that does not discharge effluents would reduce a large amount of pollutant load on aquatic bodies. In this study, eel were reared in a closed recirculating system, which consisted of a rearing tank, a foam separation unit, a nitrification unit and a denitrification unit. The foam separation unit has an inhalation-type aerator and supplies air bubbles to the rearing water. The growth of eel, which were fed a commercial diet, was satisfactory, with gross weight increases of up three times in 3 months. The survival rate under the congested experimental conditions was 91%. The foam separation unit maintained oxygen saturation in the rearing water at about 80%. Furthermore, fine colloidal substances were absorbed on the stable foam formed from eel mucus and were removed from the rearing water by foam separation. Ammonia oxidation and the removal of suspended solids were accomplished rapidly and simultaneously in the nitrification unit. The ammonia concentration and turbidity were kept at less than 1.2 mg of N per litre and 2.5 units, respectively. When the denitrification process was operated, nitrate that accumulated in the rearing water (151 mg of N per litre) was reduced to 40 mg of N per litre. The sludge was easily recovered from the nitrification and denitrification tanks, and the components were found suitable as compost. Based on these results, the intensive aquaculture of freshwater fish such as eel can be achieved using a closed recirculating system without emission. © 2003 Elsevier B.V. All rights reserved.
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SUZUKI Yoshihiro, MARUYAMA Toshiroh
Journal of Japan Society on Water Environment 26 ( 11 ) 757 - 763 2003.11
Language：Japanese Publishing type：Research paper (scientific journal) Publisher：Japan Society on Water Environment
If it is possible to develop an efficient process of removing estrogens from wastewater during sewage treatment, the load of endocrine disrupting chemicals in the water environment could be greatly reduced. In this study, the removal of estrogens from municipal wastewater by coagulation and foam separation using coagulant and milk casein was examined. The ELISA method was used to measure the efficiency of estrogen removal. In the conventional foam separation method, the removal efficiency of suspended solids was very high. However, most of the estrogen remained in the treated water since approximately 95% of the total estrogen in wastewater was in the dissolved fraction, while the amount of estrogens in the solid fraction was extremely small. Therefore, the removal of dissolved estrogen was difficult using the conventional foam separation process for removing solids. The addition of powdered activated carbon was examined as a pretreatment process. The adsorption efficiency of estrogen to activated carbon was markedly higher than that of other soluble fractions such as E260 (ultraviolet absorbance at 260 nm), chromaticity, and dissolved organic carbon in wastewater. With the addition of powdered activated carbon, both suspended solids and estrogen could be removed by coagulation and foam separation. The removal efficiencies of turbidity and estrogen were 99% and 94%, respectively, under the following dosage conditions: activated carbon, 50mg·l-1 ; ferric coagulant, 30mg-Fe·l-1 ; and casein, 50mg·l-1.
DOI： 10.2965/jswe.26.757
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Monitoring of Estrogens in Urban Effluents and in the Receiving River Water Reviewed
SUZUKI Yoshihiro, TAIRA Hiroyasu, MASUDA Sumio, TAKAHASHI Nobuyuki, MITSUYAMA Munehito, SHIMOTSU Yoshihiro, MARUYAMA Toshiroh
Journal of Japan Society on Water Environment 26 ( 11 ) 791 - 795 2003.11
Language：Japanese Publishing type：Research paper (scientific journal) Publisher：Japan Society on Water Environment
Very few investigations of the concentrations of estrogens in the effluents of urban drainage systems and in the receiving river water in areas with few constructed sewerage systems have been conducted. In this study, the concentrations of estrogens in the effluents of an urban drainage system and an onsite wastewater treatment plant, and in the receiving river were monitored for six months. The concentrations of estrogens and 17β-estradiol (E2) were determined by enzyme-linked immunosorbent assay (ELISA). Most estrogens were present in the dissolved fraction of the effluents and the river water. E2, which exists in natural waters according to many reports, accounted for 24% of the estrogens and has concentrations of 4.7±3.0 ng·l-1 (n=6) and 8.6±5.8ng·l-1 (n=6) in the effluents of the urban drainage system and the onsite wastewater treatment plant, respectively. The concentrations of estrogens and E2 in the receiving river water were two to three times higher than upstream levels. In addition, the concentrations of ammonium and estrogens showed a very high correlation (r=0.986) in all samples, suggesting that the increase in the concentrations of estrogens in the receiving river water was due to the presence of human excrement in the urban drainage system.
DOI： 10.2965/jswe.26.791
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沿岸環境調査におけるCOD測定法の比較 Reviewed
鈴木祥広，菊池隆彦，丸山俊朗
用水と廃水 45 ( 11 ) 62 - 69 2003.11
Language：Japanese Publishing type：Research paper (scientific journal)
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Removal of Suspended Solids by Coagulation and Foam Separation Using Coagulant and Milk Casein
MARUYAMA Toshro, SUZUKI Yoshihiro
Kagaku k(0xFADE)gaku 67 ( 3 ) 147 - 149 2003.3
Language：Japanese Publishing type：Research paper (scientific journal)
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Removal of suspended substances by coagulation and foam separation from municipal wastewater Reviewed
Suzuki Y., Maruyama T., Tegane H., Goto T.
Water Science and Technology 46 ( 11-12 ) 183 - 188 2002.12
Language：English Publishing type：Research paper (scientific journal) Publisher：Water Science and Technology
A new method for solid-liquid separation for wastewater incorporating simple operation and shortened treatment time is necessary for improvement of sewage systems. In this study, removal of suspended solids from municipal wastewater by coagulation and foam separation using coagulant and milk casein was examined. By adding casein before the foam separation process, the removal of suspended substances was dramatically improved. The optimum condition for treating sewage was 20 mg-Fe/L of FeCl 3 , 3 mg/L of casein, and pH 5.5, which resulted in a removal rates of over 98% for turbidity and SS. A removal of 96-98% was also possible for phosphate and anionic surfactant. When PAC was used, the floc was also efficiently recovered in foam by the addition of casein. It became clear that coagulation and foam separation using casein as the collector is an effective method for removing suspended solids in municipal wastewater in a short time (within 10 min).
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酸性重金属廃水の処理における中和沈殿法とゼオライト吸着法の比較 Reviewed
鈴木祥広，淀川育美，亀谷卓司，丸山俊朗，中澤隆雄，湊敬文
環境工学研究論文集 39 485 - 493 2002.11
Language：Japanese Publishing type：Research paper (scientific journal)
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SUZUKI Yoshihiro, MARUYAMA Toshiroh
Japan journal of water pollution research 25 ( 8 ) 477 - 483 2002.8
Language：Japanese Publishing type：Research paper (scientific journal) Publisher：Japan Society on Water Environment
Using milk casein and several kinds of surfactants as chemical agents, removal of suspended solids by coagulation and foam separation with dispersed air was examined. Casein functioned both as a collector and a frother, and coagulating flocs were almost perfectly recovered in foam generated from the liquid. Although oleic acid of anionic surfactant functioned as a collector, the removal efficiency of suspended solids was lower than that of casein. In contrast, cationic, amphoteric, and nonionic surfactants did not function act as collectors. It was clarified that casein had a much greater capacity for producing the hydrophobic interface of flocs than the surfactants used. However, all of the surfactants could also be utilized as frothers for recovering the hydrophobic flocs with casein.<br>For municipal wastewater treatment, a very high removal efficiency was obtained with a small amount of casein (3mg·<i>l</i><sup>-1</sup>), because detergent contained in the wastewater functioned as a frother. In this method using casein, detergent is one of the object substances in wastewater. It is utilized as a foaming agent and is removed with foam.
DOI： 10.2965/jswe.25.477
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Removal of suspended solids by coagulation and foam separation using surface-active protein
Suzuki Y., Maruyama T.
Water Research 36 ( 9 ) 2195 - 2204 2002.5
Language：Japanese Publishing type：Research paper (scientific journal) Publisher：Water Research
By using several kinds of surface-active proteins as a chemical agent that combined collector with frother, removal of suspended substances by coagulation and foam separation with dispersed air was examined. Milk casein showed the greatest capability of suspension removal, and coagulating flocs formed by clay particles and iron hydroxide were almost perfectly recovered in foam generated from the liquid, even in the case of freshwater and seawater suspension at neutral pH. In contrast, the removal efficiency was extremely low using sodium dodecyl sulfate (SDS). Casein had a much greater capability for removing solids than SDS as a result of the high adsorptive activity of casein on the floc. For municipal wastewater treatment, the removal efficiency of turbidity and suspended solids was over 98% with the condition of iron coagulant (FeCl 3 ) 20mg-Fe/L and casein 3mg/L and pH 5-6. Moreover, this method proved to be an effective treatment for polluted saline water (salinity 1.5%), and the suspended solids were almost perfectly recovered in foam. Here, we show a new method for quickly removing (within 7min) suspended solids from polluted wastewater utilizing casein and bubbles. © 2002 Elsevier Science Ltd. All rights reserved.
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Removal of Algae by Coagulation and Foam Separation using Polyaluminum Chloride and Milk Casein Reviewed
SUZUKI Yoshihiro, MARUYAMA Toshiroh, KAWAZOE Satoshi
Japan journal of water pollution research 25 ( 5 ) 297 - 302 2002.5
Language：Japanese Publishing type：Research paper (scientific journal) Publisher：Japan Society on Water Environment
Coagulation foam separation with dispersed air using milk casein as a collector and a frother is an effective method to remove suspended substances in water. Harmful algae, which proliferate as outbreaks in many lakes and ponds, are considered suspended organic substances. Hence, the applicability of this method for algal removal is promising. In this study, removal of algae by coagulation and foam using polyaluminum chloride (PAC) and casein was examined.<br>Highly effective processing was achieved within 10 min by adjusting pH and dosages of PAC and casein. The most important consideration in the foam separation process is adding the proper amount of casein, which functions as both collector and frother. The removal efficiency of <i>Microcystis aeruginosa</i>, <i>Selenastram capriornutum</i>, and <i>Chlorella pyreniodosa</i> was over 97% when PAC and casein were added at a dosage of 3 mg-Al·<i>l</i><sup>-1</sup> and 15 mg·<i>l</i><sup>-1</sup>, respectively at pH 7-8. The percentage of liquid volume of collapsed foam in the total amount of algal suspension was about 2%. Approximately 100% of the added PAC and casein were recovered from the treated water. These results prove that this novel method has a high efficiency and applicability in removing algae from aquatic blooms.
DOI： 10.2965/jswe.25.297
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SUZUKI Yoshihiro, MARUYAMA Toshiroh
Japan journal of water pollution research 25 ( 3 ) 163 - 169 2002.3
Language：Japanese Publishing type：Research paper (scientific journal) Publisher：Japan Society on Water Environment
In coagulation and foam separation method using protein (casein or gelatin), the effect of saline on removal of suspended matters was examined. When casein was used as collector and frother, the extremely high treatability for kaolin suspension contained NaCl (10,000mg·<i>l</i><sup>-1</sup>) was observed. The turbidity removal efficiency was over 99% by using cassein. In comparison with NaCl free kaolin suspension, the optimum dosage of casein decreased in about 1/3. In contrast, the treatment remarkably lowered using gelatin with NaCl. Adsorptions of casein on suspended particles such as kaolin, Fe<sub>2</sub>O<sub>3</sub>, and graphite, were increased under NaCl coexistence, however, gelatin adsorption remarkably decreased. It was proven that the adsorption of protein on the suspended particle was the important factor that controls the treatment of this method. Coagulation and foam separation using casein showed the high applicability for not only general sewage but also high saline wastewater. In the condition of ferric coagulant 20mg-Fe·<i>l</i><sup>-1</sup>, casein 2-3 mg·<i>l</i><sup>-1</sup>, pH 5.6-5.7, 98-99% removal rates were obtained. Furthermore, this method was very effective for removal of suspended solids from estuarine saline water.
DOI： 10.2965/jswe.25.163
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凝集・泡沫分離法による高塩分濃度濁水の処理 Reviewed
鈴木祥広，丸山俊朗
水環境学会誌 25 ( 3 ) 163 - 169 2002.3
Language：Japanese Publishing type：Research paper (scientific journal)
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Toxicity Evaluation of Disinfected Sewage Effluents using the Algal Growth Inhibition Assay. Reviewed
SUZUKI Yoshihiro, MORISHITA Reiko, TAKAMI Tohru, MARUYAMA Toshiroh
JEC 12 ( 1 ) 97 - 103 2002.3
Language：Japanese Publishing type：Research paper (scientific journal) Publisher：Japan Society for Environmental Chemistry
Chlorine-disinfected sewage effluent poses a risk to aquatic organisms, prompting the need for an innocuous alternative disinfection method. In this study, the toxicity of secondary effluent disinfected with chlorine, chlorine dioxide, ozone and UV irradiation was evaluated by the algal growth test using the green alga <I>Selenastrum capricornutum</I>. Algal growth was significantly inhibited in test media containing 10% chlorinated water. In the chlorination process, about 50% of chlorine remained in the disinfected water as oxidant, while about 80% of residual oxidant was monochloramine (NH<SUB>2</SUB>Cl) . NH<SUB>2</SUB>Cl is the most toxic substance that inhibits algal growth in chlorinated sewage effluent. On the other hand, chlorine dioxide and ozone disinfection apparently did not inhibit algal growth, but the possibility of chlorophyll biosynthesis inhibition was indicated. Effluent dechlorinated with sodium sulfite, which removes residual oxidants such as NH<SUB>2</SUB>Cl, did not inhibit algal growth. Our results have shown that the algal toxicity of the disinfection methods follows this order: chlorine >> chlorine dioxide > ozone. In contrast, UV-irradiated effluent did not harm the algae. This shows that UV irradiation, which is harmless to aquatic organisms, is adequate enough for disinfecting treated sewage effluent.
DOI： 10.5985/jec.12.97
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SUZUKI Yoshihiro, YODOGAWA Ikumi, KAMETANI Takuji, MARUYAMA Toshiroh, NAKAZAWA Takao, MINATO Takafumi
Doboku Gakkai Ronbunshuu G 39 485 - 493 2002
Language：Japanese Publishing type：Research paper (scientific journal) Publisher：Japan Society of Civil Engineers
Neutralizing precipitation and adsorption using zeolite as an adsorbent are examined and compared as methods for removing heavy metals from acid mine drainage and acid industrial wastewater. Both methods produced effluent satisfying standard pollutant levels from synthetic mine drainage (pH 2, Cd<SUP>2+</SUP> 5 mg/L, Cu<SUP>2+</SUP> 50 mg/L, Zn<SUP>2+</SUP> 300 mg/L, Al<SUP>3+</SUP> 300 mg/L, Fe<SUP>2+</SUP> 1000 mg/L). However, neutralization produced almost twice as much sediment as zeolite adsorption. In the processing of synthetic acid industry wastewater (pH 2, Cr<SUP>3+</SUP> 50 mg/L, Cd<SUP>2+</SUP> 50 mg/L, Cu<SUP>2+</SUP> 50 mg/L, Ni<SUP>2+</SUP> 100 mg/L, Zn<SUP>2+</SUP> 100 mg/L), all heavy metals in the precipitation-treated effluent except for Cd were below the standard level at pH 9-10, whereas all metals were reduced to below the standard with the addition of 40-60g/L of zeolite. The simple process of adding zeolite as an adsorbent simultaneously neutralizes and removes heavy metals from acid drainage. Zeolite, derived relatively cheaply from fly ash, therefore appears to be a highly suitable absorbent for the removal of heavy metals from acid drainage, and is expected to become highly cost-effective tool if a method for the regeneration of spent zeolite can be developed.
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SUZUKI Yoshihiro, MARUYAMA Toshiroh
Japan journal of water pollution research 24 ( 5 ) 317 - 324 2001.5
Language：Japanese Publishing type：Research paper (scientific journal) Publisher：Japan Society on Water Environment
Foam separation using a coagulant (iron or aluminum) and milk casein is effective for removing suspended matter such as kaolin particles, suspended solids in wastewater, and phytoplankton. However, the function of casein in this separation is unclear. In this study, to clarify the role of casein in coagulation and foam separation, the characteristics of casein adsorption onto flocs that were made up of kaolin and Fe(OH)<sub>3</sub> and the removal of suspended substances by the separation were investigated.<br>Both of adsorbing casein onto the flocs as a collector and remaining casein in the solution as a frother were necessary in order to obtain the high removal rate (above 90%). The optimum pH range was 6.8-7.6. The required amount of adsorbing casein onto the flocs was 0.5g-casein/g-Fe. To obtain more than 90% turbidity removal from the suspended solution of kaolin (200mg·<i>l</i><sup>-1</sup>), greater than 5mg·<i>l</i><sup>-1</sup> of residual casein with 10mg-Fe·<i>l</i><sup>-1</sup> of coagulant dosage was needed. The amounts of adsorbing casein and the concentration of residual casein were estimated from the adsorption rate of casein. The suitable dosage of casein and the mixing time for the foam separation were determined by the adsorption rate.
DOI： 10.2965/jswe.24.317
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MARUYAMA Toshiroh, SUZUKI Yoshihiro, SAKAZOE Satoshi, CHUGANJI Nobuaki, DOTE Yutaka
Japan journal of water pollution research 24 ( 3 ) 159 - 167 2001.3
Language：Japanese Publishing type：Research paper (scientific journal) Publisher：Japan Society on Water Environment
To clarify the treatability of kaolin suspension by coagulation and foam separation method using poly aluminum chloride (PAC) and milk casein (casein), the characteristics of pH, dosage of PAC and casein, operating conditions such as foam separation time and air flow rate, and effects of alkalinity were examined. The results obtained by this study can be summarized as follows.<br>(1) The conditions to treat the sample of 200mg·<i>l</i><sup>-1</sup> kaolin suspension containing 50mg·<i>l</i><sup>-1</sup> of NaHCO<sub>3</sub> to under 2 turbidity units were obtained to be pH8.5-10, PAC 10mg-Al·<i>l</i><sup>-1</sup>, casein 15mg·<i>l</i><sup>-1</sup>, foam separation time of 5min, air flow rate of 0.2<i>l</i>·min<sup>-1</sup>.<br>(2) The sample of 50-1,000mg·<i>l</i><sup>-1</sup> kaolin suspension can be treated to under 2 turbidity units by controlling the dosages of PAC and casein.<br>(3) The requirement amount of casein was considered to be the sum of a portion of adsorbing onto the flocs as a collector and another portion of residual as a frother to remove flocs by coagulation and foam separation.<br>(4) Optimum pH range expanded to neutral side with NaHCO<sub>3</sub> dosage increased. Optimum pH range for 200mg·<i>l</i><sup>-1</sup> kaolin suspension changed from 8.5-10 at 50mg-NaHCO<sub>3</sub>·<i>l</i><sup>-1</sup> to 7-10 at 150mg-NaHCO<sub>3</sub>·<i>l</i><sup>-1</sup>.<br>(5) Optimum pH range was 6.5-9 for 200mg·<i>l</i><sup>-1</sup> kaolin suspension of tap-water.<br>From these results, it was clarified that the coagulation and foam separation using PAC and casein was very effective to remove suspended matters such as kaokin particles.
DOI： 10.2965/jswe.24.159
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凝集・泡沫分離法に適したタンパク質の懸濁粒子への吸着特性 Reviewed
鈴木祥広，丸山俊朗
環境工学研究論文集 37 237 - 245 2000.11
Language：Japanese Publishing type：Research paper (scientific journal)
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凝集・泡沫分離法による淡水赤潮Peridinium bipesの除去 Reviewed
仲元寺宣明，鈴木祥広，丸山俊朗
環境工学研究論文集 37 259 - 266 2000.11
Language：English Publishing type：Research paper (scientific journal)
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Phytotoxicity of the new antifouling compound Irgarol 1051 and a major dehration product Reviewed
H. Okamura, I. Aoyama, T. Takami, T. Maruyama, Y. Suzuki, M. Matsumoto, I. Katsuyama, J. Hamada, T. Beppu, O. Tanaka, R. J. Maguire, D. Liu, Y. Lau, G. J. Pacepavicus
Marine Pollution Bulletin 40 ( 9 ) 754 - 763 2000.9
Language：English Publishing type：Research paper (scientific journal)
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Removal of Suspended Matter from an Aqueous Solution by Foam Separation with Fish Mucus Reviewed
SUZUKI Yoshihiro, MARUYAMA Toshiroh
Japan journal of water pollution research 23 ( 3 ) 181 - 186 2000.3
Language：Japanese Publishing type：Research paper (scientific journal) Publisher：Japan Society on Water Environment
An experimental investigation of the removal of suspended matter from an aqueous solution was carried out with a foam separation batch system using fish mucus as the chemical. Flounder and eel mucus showed a high foaming capacity. The capacity was influenced by changes in pH and by the presence of salts in the solution. The capacity of eel mucus was weaken in the weak acidic solution (pH 5), and was enhanced in the alkaline solution (pH 10). The capacity of both types of mucus were elevated with addition of NaCl. The capacity of flounder mucus was extremely high in seawater, and the height of foaming layer was 7 times higher than in distilled water at the same concentration. When the flounder mucus was added to the bubbling solution (above 3mg · <i>l</i><sup>-1</sup>), the suspended kaolin particles were adsorbed on the foam layer and were removed from the seawater by separation. The removal efficiency was 99%. The eel mucus also removed the kaolin in the presence of salts. Foam separation is a suitable method for removing suspended matter from fish rearing water that contains fish mucus.
DOI： 10.2965/jswe.23.181
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Effects of pH and Coexistent Substances on the Foam Formation of a Protein Solution Reviewed
SUZUKI Yoshihiro, MARUYAMA Toshiroh
Japan journal of water pollution research 23 ( 2 ) 108 - 115 2000.2
Language：Japanese Publishing type：Research paper (scientific journal) Publisher：Japan Society on Water Environment
To establish a foam separation technique using proteins as a foaming reagent, it is important to know the foaming characteristics of various protein solutions and to demonstrate the effective application of these proteins. In this study, the effects of pH and coexistent substances on the foam formation of various proteins were examined.<br>The results are as follows.<br>(1) The foaming capacity of globular proteins such as casein, hemoglobin, soy protein, and albumin was enhanced in both strong acid and alkaline solutions. In contrast, gelatin, which is a fibrous protein, had only a slight dependency on pH.<br>(2) The foam formation of proteins varied with the differences of cations in the solution. The enhanced potential were Na<sup>+</sup>=K<sup>+</sup>>Mg<sup>2+</sup>>Sr<sup>2+</sup>>>Ca<sup>2+</sup> in order. Anions had no effect on foaming capacity.<br>(3) The foaming capacity of casein was elevated with the addition of LAS (sodium linear-dosecylbenzenesulfonate). In contrast, the capacity of casein was lowered by the presence of SDS (sodium dodecyl suophate).<br>(4) Globular proteins showed denaturation, dissociation and association with pH and coexistent substances, and these change affected foam formation.<br>It is possible to generate the optimum amount of proteinaceous foam by taking advantage of each protein's unique characteristics.
DOI： 10.2965/jswe.23.108
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A Test Method for Measuring the Foaming Capacity of Protein Solutions Reviewed
SUZUKI Yoshihiro, MARUYAMA Toshiroh
Japan journal of water pollution research 23 ( 2 ) 122 - 125 2000.2
Language：Japanese Publishing type：Research paper (scientific journal) Publisher：Japan Society on Water Environment
In order to use protein as a chemical to bring about effective foam separation, it is necessary to understand foaming capacity and the factors that affect this capacity. In this study, the effect of various protein solutions on foaming capacity were measured using a bubbling column. The test compounds were casein, soy protein, albumin, hemoglobin, gelatin, and LAS.<br>The foaming capacity of a protein and a surfactant were evaluated by determining the height of the foam at the time of splitting or decaying within the bubbling column under constant conditions of air flow, volume of test solution, and water temperature. The most effective protein was casein followed by hemoglobin, soy protein, gelatin, and albumin. The capacity of casein was comparable to that of LAS. Under appropriate conditions, 0.3<i>l</i>-air · min<sup>-1</sup>, 100m<i>l</i> sample, 20°C, and pH6.9, the concentrations of casein and LAS required to make a foam height of 30cm (column diameter, 2.6cm) were 4.4mg · <i>l</i><sup>-1</sup> and 4.6mg · <i>l</i><sup>-1</sup>, respectively.
DOI： 10.2965/jswe.23.122
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SUZUKI Yoshihiro, MARUYAMA Toshiroh, SATO Daisuke, KANDA Takeshi, MICHISHITA Tamotsu, Yoshihiro Suzuki, Toshiroh Maruyama, Daisuke Sato, Takeshi Kanda, Tamotsu Michishita, Department of Civil and Environmental Engineering Miyazaki University, Department of Civil and Environmental Engineering Miyazaki University, Department of Civil and Environmental Engineering Miyazaki University, Fisheries Research Laboratory Miyazaki University, Fisheries Research Laboratory Miyazaki University
NSUGAF 66 ( 1 ) 1 - 9 2000.1
Language：Japanese Publishing type：Research paper (scientific journal) Publisher：The Japanese Society of Fisheries Science
In this study, water quality and mass balances in the closed recirculating culture of Japanese flounder were examined. The closed system consisted of rearing thank, foam-separation and nitrification units, pH and temperature controlling units, and a circulation pump. Fish were fed commercial pellet diet for 90 days. Average values of oxygen saturation and turbidity in the rearing water through the culture were 96% and 3.1 TU, respectively. Ammonia was mostly kept at less than 1mg-N/l, and nitrate increased linearly according to the amount of diet supplied. It is estimated that 33% of dietary carbon (C) was accumulated in the fish, as well as 52% of nitrogen (N), and 26% of phosphorus (P). The carbon released as CO<SUB>2</SUB> was 63%. Nitrate in the rearing water corresponded to 28% of N-input, and 66% of P was settled in the nitrification unit as precipitate.
DOI： 10.2331/suisan.66.1
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Suzuki Y., Maruyama T., Sato D., Kanda T., Michishita T.
Nippon Suisan Gakkaishi (Japanese Edition) 66 ( 1 ) 1 - 9 2000.1
Language：Japanese Publishing type：Research paper (scientific journal) Publisher：Nippon Suisan Gakkaishi (Japanese Edition)
In this study, water quality and mass balances in the closed recirculating culture of Japanese flounder were examined. The closed system consisted of rearing thank, foam-separation and nitrification units, pH and temperature controlling units, and a circulation pump. Fish were fed commercial pellet diet for 90 days. Average values of oxygen saturation and turbidity in the rearing water through the culture were 96% and 3.1 TU, respectively. Ammonia was mostly kept at less than 1 mg-N/l, and nitrate increased linearly according to the amount of diet supplied. It is estimated that 33% of dietary carbon (C) was accumulated in the fish, as well as 52% of nitrogen (N), and 26% of phosphorus (P). The carbon released as CO 2 was 63%. Nitrate in the rearing water corresponded to 28% of N-input, and 66% of P was settled in the nitrification unit as precipitate.
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SUZUKI Yoshihiro, MARUYAMA Toshiroh, TAKEMOTO Susumu, ODA Risa
Journal of Japan Society on Water Environment 22 ( 11 ) 896 - 903 1999.11
Language：Japanese Publishing type：Research paper (scientific journal) Publisher：Japan Society on Water Environment
If a closed recirculating aquaculture system that need not discharge the effluents is developed, a large amount of the pollutant load on water bodies can be reduced. In this study, rearing experiment of eel were reared in a closed recirculating system. The system consisted of a fish tank, a foam separation unit, nitrification and denitrification units, pH and temperature control units, and a circulation pump. The foam separation unit has an air inhalation-type aerator and supplies numerous bubbles into the rearing water. Fish were fed a commercial diet for 3 months.The survival rate of eel was 100% during the experiment under the congested condition. The foam separation unit kept oxygen saturation in the rearing water at about 90%. Furthermore, colloidal matters were absorbed on stable foam formed from eel mucus and were removed from the rearing water by foam separation. Ammonia oxidation and the removal of suspend matters were accomplished rapidly at the same time with the nitrification unit, and ammonia concentration and turbidity were kept at less than 0.21mg-N·l-1 and 0.981 TU, respectively. When the denitrification process was operated, nitrate accumulated in the rearing water was reduced to a concentration less than 7mg-N·l-1. Based on these results, an intensive aquaculture of freshwater fish such as eel can be achieved by a closed recirculating system.
DOI： 10.2965/jswe.22.896
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MARUYAMA Toshiroh, SUZUKI Yoshihiro, SATO Daisuke, KANDA Takeshi, MICHISHITA Tamotsu, Toshiroh Maruyama, Yoshihiro Suzuki, Daisuke Sato, Takeshi Kanda, Tamotsu Michishita, Department of Civil and Environmental Engineering Miyazaki University, Department of Civil and Environmental Engineering Miyazaki University, Department of Civil and Environmental Engineering Miyazaki University, Fisheries Research Laboratory Miyazaki University, Fisheries Research Laboratory Miyazaki University
NSUGAF 65 ( 5 ) 818 - 825 1999.9
Language：Japanese Publishing type：Research paper (scientific journal) Publisher：The Japanese Society of Fisheries Science
Rearing experiment of Japanese flounder Paralichthys olivaceus was conducted with two different culture systems, a closed recirculating system having a foam-separation unit and a flow-through system in which natural seawater was continuously supplied. The closed recirculating system consisted of a fish tank of 1m<SUP>3</SUP> in water volume, foam-separation and nitrification units, pH and temperature controlling units, and a circulation pump. A key feature of this system is the foam-separation unit, which is equipped with an air inhalation-type aerator that vigorously injects numerous fine bubbles into the rearing water. Fish were fed commercial pellet diet for 90 days. The survival rate of fish was 93.5%, and the gross weight of fish increased from 28.4kg to 50.0kg during the experiment in the closed recirculating system without the effluent. In the flow-through system, the survival rate was 98%, and the weight increased from 33.8kg to 64.1kg. Based on these results, intensive aquaculture can be achieved with the closed recirculating system.
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The role of terrestrial humic substances on the shift of kelp community to crustose coralline algae community of the southern Hokkaido Island in the Japan Sea Reviewed
K. Matsunaga, T. Kawaguchi, Y. Suzuki, G. Nigi
Journal of Experimental Marine Biology and Ecology 241 ( 2 ) 193 - 205 1999.8
Language：English Publishing type：Research paper (scientific journal)
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TAKAMI Tohru, MARUYAMA Toshiroh, SUZUKI Yoshihiro, MIURA Akio
Journal of Japan Society on Water Environment 22 ( 1 ) 29 - 34 1999.1
Language：Japanese Publishing type：Research paper (scientific journal) Publisher：Japan Society on Water Environment
In the short-term bioassay using Porphyra yezoensis conchospores, it is basically important to clarify the most appropriate exposure period and end point to evaluate the effects of toxicants on the growth of Porphyra yezoensis conchospores. In this study, short-term bioassays (120 hours) were conducted on copper (Cu) and monochloramine (NH2Cl), which have different chemical characteristics. Three kinds of end points (survival ratio, germination ratio and growth ratio) at exposure periods every 24 hours were compared to define the most appropriate exposure period and end point.The minimum LOECs (lowest-observed-effect concentration) for Cu occurred at exposure period of 96 hours in the three kinds of end points. The 96-h LOECs from the survival ratio, the germination ratio and the growth ratio were 0.046 ± 0.026mg Cu·l-1 (n=5), 0.033 ± 0.027mg Cu·l-1 (n=5), 0.021 ± 0.019mg Cu·l-1 (n=5), respectively. The minimum LOECs for NH2Cl occurred at exposure period of 96 hours in the survival ratio and the growth ratio of 0.093 ± 0.026mg Cl2·l-1 (n=5) and 0.038 ± 0.016mg Cl2·l-1 (n=5), respectively. The minimum LOEC (0.036 ± 0.000mg Cl2·l-1, n=5) for NH2Cl from the germination ratio occurred at the exposure period of 48 hours.Therefore, taking into account of the simplicity of bioassay and its sensitivity to toxicants, it is concluded that the most appropriate exposure period and end point is 96 hours for Cu and 48 hours for NH2Cl judging from the end point of the germination ratio.
DOI： 10.2965/jswe.22.29
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海藻（スサビノリ殻胞子）を用いた生物検定における適切な暴露時間と判定指標の検討 Reviewed
高見徹，丸山俊朗，鈴木祥広，三浦昭雄
水環境学会誌, 22巻, 1号, 29-34頁 22 ( 1 ) 29 - 34 1999.1
Language：Japanese Publishing type：Research paper (scientific journal)
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Maruyama T., Suzuki Y., Sato D., Kanda T., Michishita T.
Nippon Suisan Gakkaishi (Japanese Edition) 65 ( 5 ) 818 - 825 1999.1
Language：Japanese Publishing type：Research paper (scientific journal) Publisher：Nippon Suisan Gakkaishi (Japanese Edition)
Rearing experiment of Japanese flounder Paralichthys olivaceus was conducted with two different culture systems, a closed recirculating system having a foam-separation unit and a flow-through system in which natural seawater was continuously supplied. The closed recirculating system consisted of a fish tank of 1 m 3 in water volume, foam-separation and nitrification units, pH and temperature controlling units, and a circulation pump. A key feature of this system is the foam-separation unit, which is equipped with an air inhalation-type aerator that vigorously injects numerous fine bubbles into the rearing water. Fish were fed commercial pellet diet for 90 days. The survival rate of fish was 93.5%, and the gross weight of fish increased from 28.4 kg to 50.0 kg during the experiment in the closed recirculating system without the effluent. In the flow-through system, the survival rate was 98%, and the weight increased from 33.8 kg to 64.1 kg. Based on these results, intensive aquaculture can be achieved with the closed recirculating system.
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MARUYAMA Toshiroh, SUZUKI Yoshihiro
Doboku Gakkai Ronbunshuu B 15 i - xiv 1999
Language：Japanese Publishing type：Research paper (scientific journal) Publisher：Japan Society of Civil Engineers
DOI： 10.2208/prooe.15.i
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TAKAMI Tohru, MARUYAMA Toshiroh, SUZUKI Yoshihiro, KAIGA Nobuyoshi, MIURA Akio
Journal of Japan Society on Water Environment 21 ( 11 ) 711 - 718 1998.11
Language：Japanese Publishing type：Research paper (scientific journal) Publisher：Japan Society on Water Environment
Chlorination of secondary effluents produce strong toxic substance such as monochloramine or oxidant on growth of aquatic organisms. Therefore, alternative disinfection methods to chlorination should be considered. However, the effect of effluents disinfected with the alternatives on seaweed has not been clarified. In this study, the toxicity of secondary effluents disinfected with chlorine (NaOCl), chlorine dioxide (ClO2), ozone (O3), and ultraviolet rays (UV) were investigated by bioassay using Porphyra yezoensis conchospores. Secondary effluents used in this study were disinfected with disinfectants or rays which inactivated coliform groups in secondary effluents of 99.9%. Lowest-observed-effect concentrations (LOECs) of secondary effluents disinfected with NaOCl, ClO2, and O3 for germination ratio of conchospores were 1.0, 10, and 100% of effluent concentration, respectively. The toxicity of effluents disinfected with NaOCl and ClO2 were very strong. In contrast, the effluents disinfected with UV rays did not affect the germination of conchospores. The toxicity of effluents disinfected with NaOCl, ClO2, and O3 were considered to depend on initial total residual oxidant (TRO). Dechlorination with Na2SO3 of effluents disinfected with NaOCl or ClO2 did not affect the germination of conchospores, even in 100% of effluent concentration.
DOI： 10.2965/jswe.21.711
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藻類増殖阻害試験における生物量の測定方法が毒性評価に及ぼす影響 Reviewed
鈴木祥広，森下玲子，高見徹，丸山俊朗
環境工学研究論文集 35 101 - 109 1998.11
Language：Japanese Publishing type：Research paper (scientific journal)
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Riverine input of bioavailable iron supporting phytoplankton growth in Kesennuma Bay Reviewed
K. Matsunaga, J. Nishioka, K. Kuma, T. Toya, Y. Suzuki
Water Research 32 ( 11 ) 3436 - 3442 1998.11
Language：English Publishing type：Research paper (scientific journal)
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Riverine input of bioavailable iron supporting phytoplankton growth in Kesennuma Bay (Japan)
Matsunaga K., Nishioka J., Kuma K., Toya K., Suzuki Y.
Water Research 32 ( 11 ) 3436 - 3442 1998.11
Language：Japanese Publishing type：Research paper (scientific journal) Publisher：Water Research
The effects of riverain iron and nutrient inputs on phytoplankton growth in Kesennuma Bay were studied. The effects of iron and Fulvic acid-iron complex additions on phytoplankton growth were studied in iron-enriched and -limited culture experiments of coastal marine diatom Chaetoceros sp. (the dominant species inside and outside of the bay) using media prepared from bay and outer waters. Bay water is not iron-limited. The addition of Fe(lII) to bay water or autoclaved bay water gave no increase in cell yield. However, when bay water was autoclaved after UV-irradiation, there was little growth. This suggests that the UV irradiation destroyed organic compounds that affected iron bioavailability. Outer water is iron-limited. The addition of Fe(III) to outer water increased cell yield and iron-enriched outer water prepared by autoclaving after adding Fulvic acid-Fe increased also cell yield. When outer water after adding Fe(III) was autoclaved, there was little growth. This suggests that fulvic acid made the iron bioavailable. The riverain inputs of organically bound iron, such as fulvic acid-Fe, and nutrients probably play an important role for supporting phytoplankton growth in the bay.
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SUZUKI Yoshihiro, MARUYAMA Toshiroh, TAKAMI Tohru, MIURA Akio
Journal of Japan Society on Water Environment 21 ( 10 ) 670 - 675 1998.10
Language：Japanese Publishing type：Research paper (scientific journal) Publisher：Japan Society on Water Environment
Effects of suspended and accumulated kaolinite particles on the adhesion and the development of Undaria pinnatifida zoospores on the substratum were investigated under the following three types of condition; Case-1: suspended particles together with zoospores, Case-2: zoospores released after accumulation of particles on the substratum, and Case-3 : accumulated particles on zoospores adhered on the substratum.Case-2 was the most effective inhibition for the adhesion of zoospores, and 50% of effective concentration of particles (EC50) was 29 μg·cm-2. It was difficult for gametophytes to develop to sporophytes in Case-3. Furthermore, in comparing Undaria zoospores with Porphyra conchospores, the zoospores showed higher tolerance to suspended particles.
DOI： 10.2965/jswe.21.670
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森林起源のフルボ酸鉄がコンブやワカメの生長に果たす効果 Reviewed
松永 勝彦, 和 吾郎, 鈴木 祥広, 安井 肇, ディーン グリサダ
日本海水学会誌 52 ( 5 ) 315 - 318 1998.10
Language：Japanese Publishing type：Research paper (scientific journal) Publisher：日本海水学会
森林起源のフルポ酸鉄が海藻に果たす効果について, コンブと.ワカメの遊走子 (胞子) ならびにコンブの幼体を用いて検討した.遊走子が卵を形成する割合を フルポ-Fe, EDTA-Fe, 無定形水酸化鉄をそれぞれ0.2μMとして, 10℃で培養した.30日後, 卵形成はそれぞれ70, 54, 25%であった. ワカメの卵形成についてはそれぞれ55, 42, 25%であった.また, 幼体の生長はフルポ酸-Fe共存下では無定形水酸化鉄に比べ3倍も速かった.<BR>コンブによる鉄の摂取速度を フルポ酸-Feあるいは無定形水酸化鉄を用いて測定したが, フルポ酸-Feの方が1オーダ速い摂取速度を示した. フルポ酸-Fe共存下で卵形成割合が高いことならびに幼体の生長が速いことは鉄摂取速度の相違によって説明出来ると思われる.<BR>なお, 本研究はソルト・サイエンス研究財団のプロジェクト研究「 沿岸海水環境の変化と生態系への影響」の一部として行なった.プ ロジェクトリーダーである東京大学名誉教授堀部純男先生にまた有益なご助言をいただいた東京農業大学名誉教授杉二郎先生に心から謝意を表します.
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Suzuki Y., Takabayashi T., Kawaguchi T., Matsunaga K.
Journal of Experimental Marine Biology and Ecology 225 ( 1 ) 69 - 77 1998.7
Language：English Publishing type：Research paper (scientific journal) Publisher：Journal of Experimental Marine Biology and Ecology
An allelopathic substance that destroys zoospores of the brown alga, Laminaria religiosa Miyabe, was isolated by several separation techniques from the ethanol extract of the crustose coralline alga, Lithophyllum spp. A bioassay was used to test the effect of isolated fractions against the dinoflagellate, Heterosigma akashiwo Hada, and zoospores of L. religiosa. Further purification of the allelopathic substance in ether phase by silica gel column chromatography revealed that the isolated active substance had major absorption peaks at 220, 263 and 283 nm in the UV region and exhibited characteristics consistent with a nonpolar group. The results suggest that allelopathy may play an important role for reducing epiphyte growth on crustose coralline algal surfaces and may partially explain their predominance in the coastal region of the northern Japan Sea.
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MARUYAMA Toshiroh, SUZUKI Yoshihiro, KAWAZOE Satoshi, DOTE Yutaka, MASUDA Sumio
Journal of Japan Society on Water Environment 21 ( 5 ) 310 - 317 1998.5
Language：Japanese Publishing type：Research paper (scientific journal) Publisher：Japan Society on Water Environment
Red tide outbreaks kill great number of cultured fish resulting in the serious problem for fisheries. In this study, to clarify the ability of the foam-separation system for collection of red tide plankton, the optimum conditions of this system was investigated by batch system.The results are as follows : (1) It was clear that the foam-separating system was very effective for collecting plankton by combined use of a coagulant (poly ferric sulfate : PFS) and protein (casein). When added PFS and casein at dosage of 40mg-Fe·l-1 and 15mg·l-1, respectively, the recovery of Heterosigma akashiwo, Chattonella antiqua and Gymnodinum mikimotoi were 99%, and the ratio of volume of foam waste water to total amount of red tide seawater was about eight percent. The optimum dosages of PFS and casein for collecting diatom (Pheaodactylum tricornutum, Skeletonema costatum, Chaetoceros sociale) and H. akashiwo were less than that for above two red tide species.(2) Approximately 100% of dosed PFS and casein were recovered from the treated seawater. Furthermore, about 99% of phosphate was removed from the red tide seawater by coagulation.(3) AGP tests showed that the growth of red tide plankton (H. akashiwo, C. antiqua and G. mikimotoi) were strongly limited in the treated seawater.
DOI： 10.2965/jswe.21.310
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The effect of fulvic acid-Fe derived from the forest on the growth of Laminaria religiosa Miyabe and Undaria pinnatifida Suringan Reviewed
K. Matsunaga, G. Nigi, Y. Suzuki, H. Yasui, G. Deein
Bulletin of Society Sea Water Science, Japan 52 ( 5 ) 315 - 318 1998.5
Language：English Publishing type：Research paper (scientific journal)
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MARUYAMA Toshiroh, SUZUKI Yoshihiro
NSUGAF 64 ( 2 ) 216 - 226 1998.3
Language：Japanese Publishing type：Research paper (scientific journal) Publisher：The Japanese Society of Fisheries Science
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Maruyama T., Suzuki Y.
Nippon Suisan Gakkaishi (Japanese Edition) 64 ( 2 ) 216 - 226 1998.1
Language：Japanese Publishing type：Research paper (scientific journal) Publisher：Nippon Suisan Gakkaishi (Japanese Edition)
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Effect of Biomass Measurements on Toxicity Evaluation in Algal Growth Inhibition Tests.
SUZUKI Yoshihiro, MORISHITA Reiko, TAKAMI Tohru, MARUYAMA Toshiroh
Doboku Gakkai Ronbunshuu G 35 101 - 109 1998
Language：Japanese Publishing type：Research paper (scientific journal) Publisher：Japan Society of Civil Engineers
General methods for the biomass measurements in algal growth inhibition tests are cell counting, absorbance, and fluorescence, but a standard method is not restricted by the standard procedures. The possibilityof the different evaluation is present in the toxicity test by different biomass determinations.In this study, the toxicity of copper (Cu) and monochloramine (NH<SUB>2</SUB>Cl) as reference toxic substances wereevaluated from the algal growth inhibition test using green alga Selenasturum capricornutum. To determine thebiomass changes, direct cell counting, turbidity, chlorophyll with fluorescence, and ATP methods were used andthe effective concentration of Cu and NH<SUB>2</SUB>Cl were evaluated with each results. The most sensitive method of theevaluation was direct cell counting, then LOEC and EC<SUB>50</SUB> of Cu were 10 and 7 μg/l, and LOEC and EC<SUB>50</SUB> of NH<SUB>2</SUB>Cl were 7 and 19 μg-Cl<SUB>2</SUB>/l, respectively. Turbidity and fluorescence methods showed the same sensitivity for Cu, whereas these were not sensitive for NH<SUB>2</SUB>Cl. In contrast, the sensitivity of ATP method was not good for bothtoxic substances, and the evaluated values of LOEC and EC<SUB>50</SUB> with ATP were several times higher than withcounting method. It is necessary to recognize that the method for biomass measurements in algal growth test hasan effect on the estimation.
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Effect of Nutrients Condition on a Toxicity Evaluation of Monochloramine by Algal Growth Test Reviewed
SUZUKI Yoshihiro, MORISHITA Reiko, MARUYAMA Toshiroh
Journal of Japan Society on Water Environment 20 ( 11 ) 783 - 788 1997.11
Language：Japanese Publishing type：Research paper (scientific journal) Publisher：Japan Society on Water Environment
The toxicity of monochloramine (NH2Cl), which is the main by-product of sewage effluent chlorination, was evaluated from growth inhibition in different condition of nutrients by a green alga Selenastrum capricornutum. The effect of NH2C1 on algal growth was depended on the nutrients condition, and nutrients limited algal cells were more sensitive than the non-limited cells. When using the nutrient-limited algal cells for the test organisms, lowest-observed-effect concentration (LOEC) and 50% effective concentration (EC50) after 96 hours exposed period were 0.001 and 0.002 mg-Cl2·l-1, respectively.The obtained LOEC and EC50 were lower than the water quality criteria for residual oxidants and the detection limit of oxidant determination. It is clear that chemical analysis is insufficient to monitor the various effluents. From these results, an algal growth test using the nutrient-limited algal cells is very sensitive and useful for the toxicity evaluation of disinfected effluents.
DOI： 10.2965/jswe.20.783
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河口域に位置する屎尿処理場の操業開始と操業停止に伴う河口・沿岸域の底質変化およびヒロハノヒトエグサ養殖の収穫変動 Reviewed
三浦昭雄，丸山俊朗，鈴木祥広
用水と廃水 39 ( 6 ) 15 - 21 1997.6
Language：Japanese Publishing type：Research paper (scientific journal)
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TOXICITY TESTING USING CONCHOSPORES AND THEIR GERMLINGS OF PORPHYRA YEZOENSIS Reviewed
TAKAMI Tohru, MARUYAMA Toshiro, SUZUKI Yoshihiro, MIURA Akio
566 71 - 80 1997.5
Language：Japanese Publishing type：Research paper (scientific journal)
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SUZUKI Yoshihiro, MARUYAMA Toshiro, MIURA Akio, SHIN Jong-ahm
559 73 - 79 1997.2
Language：Japanese Publishing type：Research paper (scientific journal)
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Toxicity Testing Using Conchospores and Their Germlings of Porphyra Yezoensis.
Takami Tohru, Maruyama Toshiro, Suzuki Yoshihiro, Miura Akio
Doboku Gakkai Ronbunshu 1997 ( 566 ) 71 - 80 1997
Language：Japanese Publishing type：Research paper (scientific journal) Publisher：Japan Society of Civil Engineers
The objective of this study is to establish the methodology of toxicity test of detrimental substances using conchospores and their germlings of <i>Porphyra yezoensis</i>. Release of conchospores from mature free-living conchocelis took place after 7 days when the culture transfered from 23°C to 15°C temperature conditions with 10hL:14hD in 1/20PES medium, and 80% of conchospores were released for first 3 hours when the light condition was changed from off to on in a day. As substrata to be adhered conchospores, the glass plate was the most adequate and concerning the method of adhering conchospores, natural sedimentation of conchospores onto the glass plate was the most adequate. Adhesion and survival ratios of conchospores were constant, even if the date and the number of collecting conchospores were different.
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Effect of Suspended Matters on the Adhesion of Porphyra Yezoensis Conchospores. Reviewed
Suzuki Yoshihiro, Maruyama Toshiroh, Miura Akio
Doboku Gakkai Ronbunshu 1997 ( 580 ) 19 - 26 1997
Language：Japanese Publishing type：Research paper (scientific journal) Publisher：Japan Society of Civil Engineers
The effect of different kinds of suspended matters and their grain size on the adhesion onto the substrate of <i>Porphyra yezoensis</i> conchospores were investigated. The results are summarized as follows: (1) The inhibition effect of the adhesion of conchospores were depended on the size of the suspended clays, and the large particles were more effective in the inhibition than the small ones at the same concentration. (2) Five kinds of clay inhibited adhesion of conchospores in their low concentration. (3) The suspended organic matters had the smaller influence on the adhesion of conchospores than the clay particles.
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Suzuki Yoshihiro, Maruyama Toshiro, Miura Akio, Shin Jong-ahm
Doboku Gakkai Ronbunshu 1997 ( 559 ) 73 - 79 1997
Language：Japanese Publishing type：Research paper (scientific journal) Publisher：Japan Society of Civil Engineers
Effects of suspended or accumulated kaolinite particles on the adhesion and the germination of <i>Porphyra yezoensis</i> conchospores were investigated under three types of condition; 1) suspended of conchospores with particles together, 2) accumulated of particles on the substrate before conchospores adhesion, and 3) accumulated of particles on adhered conchospores. Condition-1 was the most effective, and the 50% of effective concentration (EC<sub>50</sub>) was 3μg/cm<sup>2</sup>. When condition-2, it was difficult for conchospores to germinate even though 1μg/cm<sup>2</sup> of kaolinite particles. We may, therefore, reasonably conclude that the damages of seaweed community result from generation of suspended matters by human being's developmental activities in the coastal region.
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Production of Monochloramine and Its Disappearance in Sewage Effluents by Chlorination Reviewed
SUZUKI Yoshihiro, MARUYAMA Toshiro, TAKAMI Tohru
Journal of Japan Sewage Works Association. Research journal 33 ( 407 ) 93 - 103 1996.12
Language：Japanese Publishing type：Research paper (scientific journal)
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SUZUKI Yoshihiro, MORISHITA Reiko, MARUYAMA Toshiro
Journal of Japan Society on Water Environment 19 ( 11 ) 861 - 870 1996.11
Language：Japanese Publishing type：Research paper (scientific journal) Publisher：Japan Society on Water Environment
Monochloramine (NH2Cl) which is a highly toxic pollutant is usually contained in chlorinated sewage effluents. Effects of NH2Cl and chlorinated sewage effluent on freshwater ecosystem were investigated by an algal growth test using a green alga Selenastrum capricornutum.Toxicity of NH2Cl for the alga was stronger than that of free chlorine, and NH2Cl was extremely stable in freshwater. Lowest-observed-effect concentration (LOEC) of NH2Cl after 96 hours exposure was 0.01 mg-Cl2l-1. Comparison of chlorinated effluents with non-chlorinated effluents, the algal growth was inhibited significantly in chlorinated effluents. The final chlorinated effluents collected from the sewage treatment plant also affected the growth of alga, and about 80% of total residual oxidants in the effluents was detected as NH2Cl. On the contrary, the algal growth was not inhibited in dechlorinated effuents with Na2SO3 because of disappearance of the residual oxidant. Judging from these results, it was clear that NH2Cl was the most important pollutant in chlorinated wastewater effluents for aquatic organisms.
DOI： 10.2965/jswe.19.861
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粉砕セメント固化体中有害重金属の低pH溶液への溶出に関する研究
土手 裕, 丸山 俊朗, 鈴木 祥広, 福嶋 知幸, 笹井 剛
廃棄物学会研究発表会講演論文集 = Proceedings of the Annual Conference of the Japan Society of Waste Management Experts 7 ( 2 ) 924 - 926 1996.9
Language：Japanese Publishing type：Research paper (scientific journal)
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Disappearance of Monochloramine and Production of Residual Oxidant in Seawater Reviewed
SUZUKI Yoshihiro, MARUYAMA Toshiro, TAKAMI Tohru, DOTE Yutaka
Journal of Japan Society on Water Environment 19 ( 5 ) 388 - 396 1996.5
Language：Japanese Publishing type：Research paper (scientific journal) Publisher：Japan Society on Water Environment
Monochloramine (NH2Cl) is the strongest toxic substance resulting from chlorinated sewage effluent. To estimate of NH2Cl on the growth of organisms in coastal region, disappearance of NH2Cl in seawater was investigated.Changes concentration of NH2Cl and total oxidant in artificial seawater were determined. The concentration of NH2Cl decreased with time and reached to 20% of the initial concentration after 6 hour at 30°C. On the other hand, 90% of the initial concentration of total oxidant was detected after disappearance of NH2Cl. The rate constant of NH2Cl disappearance was not concerned in the initial concentration at constant temperature. Disappearance of NH2Cl depended on water temperature, and the rate constant followed the Arrhenius equation. The rate constant and half-life value at 20°C for NH2Cl in seawater were 0.031 h-1 and 10 h. These results suggested that the effluent contained NH2Cl would be enough to effect on coastal organism until its disappearance. NH2Cl disappearance depended on salinity. However, NH2Cl in artificial seawater without KBr was stable even in the same condition. It was clear that the disappearance factor of NH2Cl was in existence of Br-. NH2Cl changed to the other oxidant with Br-, therefore, the product which may act on organisms still remained in seawater after disappearance of NH2Cl.
DOI： 10.2965/jswe.19.388
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土手 裕, 丸山 俊朗, 鈴木 祥広, 福嶋 知幸
廃棄物学会研究発表会講演論文集 = Proceedings of the Annual Conference of the Japan Society of Waste Management Experts 6 ( 1 ) 441 - 443 1995.10
Language：Japanese Publishing type：Research paper (scientific journal)
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Bioavailable iron species in seawater measured by macroalga (Laminaria japonica) uptake Reviewed
共著者：Y. Suzuki, K. Kuma, K. Matsunaga
Marine Biology 123 ( 1 ) 173 - 178 1995.7
Language：English Publishing type：Research paper (scientific journal)
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Iron requirement of brown macroalgae (Lamianria japonica, Undaria pinnatifida; Phaeophyta) and crustose coralline alga (Lithphyllum yessoense; Rhodophyta), and their competition in the northern Japan Sea Reviewed
Y. Suzuki, K. Kuma, I. Kudo, K. Matsunaga
Phycologia 34 ( 3 ) 201 - 205 1995.3
Language：English Publishing type：Research paper (scientific journal)
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Photoreduction of manganese dioxide in seawater by organic substances under ultraviolet or sunlight Reviewed
K. Matsunaga, T. Ohyama, K. Kuma, I. Kudo, Y. Suzuki
Water Research 29 ( 2 ) 757 - 759 1995.2
Language：English Publishing type：Research paper (scientific journal)
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Suzuki Y., Kuma K., Kudo I., Matsunaga K.
Phycologia 34 ( 3 ) 201 - 205 1995
Language：Japanese Publishing type：Research paper (scientific journal) Publisher：Phycologia
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Diffusion of Fe(II) from iron propagation cage and its effect on tissue iron and pigments of macroalgae on the cage Reviewed
K. Matsunaga, Y. Suzuki, K. Kuma, I. Kudo
Journal of AppliedPhycology 6 ( 4 ) 397 - 403 1994.8
Language：English Publishing type：Research paper (scientific journal)
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Effect of iron on oogonium formation, growth rate and pigments synthesis of Laminaria japonica Reviewed
Y. Suzuki, K. Kuma, K. Matsunaga
Fisheries Science 60 ( 4 ) 373 - 378 1994.4
Language：English Publishing type：Research paper (scientific journal)
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Suzuki Y., Kuma K., Matsunaga K.
Fisheries Science 60 ( 4 ) 373 - 378 1994
Language：Japanese Publishing type：Research paper (scientific journal) Publisher：Fisheries Science
The effects of iron on oogonium formation of female gametophytes, growth rate and pigment syntheses of Laminaria japonica Areschoug were investigated and compared in both soluble EDTA chelated iron (Fe(III)-EDTA) and solid amorphous hydrous ferric oxide (am-Fe(III)) media containing nitrate and phosphate. Soluble Fe(III)-EDTA [0.4-2 μM] and solid am-Fe(III) [2 μM] were found to strongly affect the oogonium formation of female gametophytes; most gametophytes in iron-free and reduced iron concentration media ( < 0.4μM in Fe(III)-EDTA, < 2μM in am-Fe(III)) continued only vegetative growth without oogonium formation. The growth rate and chlorophyll-a (Chl-a) concentration of young sporophytes significantly increased with increased iron concentration in the culture media. The growth rate and Chl-a concentration of young sporophytes cultured in am-Fe(III) media were approximately one half lower than those in Fe(III)-EDTA media, possibly as a result of the lower iron uptake rate of young sporophytes observed in am-Fe(III) media. This lower iron uptake rate may be attributed to the low solubility and the slow dissolution rate reported for solid amorphous hydrous ferric oxide in seawater. Furthermore, iron was found to promote the syntheses of fucoxanthin, chlorophyll-c, β-carotene and Chl-a in adult sporophytes. This study clearly indicates that iron plays an important role in the oogonium formation, growth rate and pigment syntheses of L. japonica. © 1994, The Japanese Society of Fisheries Science. All rights reserved.
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Solubility and dissolution rate of colloidal γ-FeOOH in seawater
Kuma K., Suzuki Y., Matsunaga K.
Water Research 27 ( 4 ) 651 - 657 1993.4
Language：Japanese Publishing type：Research paper (scientific journal) Publisher：Water Research
Solubilities and dissolution rates of colloidal γ-FeOOH (lepidocrocite), one of the typical iron oxyhydroxides, in seawater over a pH range 5.5-8.2 at 20°C were experimentally determined by dialysis techniques involving γ-activity measurements of 59 Fe. The Fe(III) dissolution rate was closely in proportion to the concentration of particulate Fe(III) in seawater and was defined as a first-order reaction. The solubilities and dissolution rate constants within the pH range 7.0-8.2 were independent of pH with values of approx. 1 × 10 -9 mol l -1 and 0.005 day -1 , respectively. This result probably indicates the existence of Fe(OH) 3 o as well as Fe(OH) 2 + in the normal pH range of seawater. The solubility and dissolution rate constants were one order of magnitude and one-third, respectively, lower than those of amorphous hydrous ferric oxide determined in a previous study. The Fe(III) dissolution rate of colloidal γ-FeOOH at the normal pH of seawater can be estimated from 0.005 × [Fe(III)particulate] (conc. day -1 ) by the concentration of particulate Fe(III) as γ-FeOOH in seawater. At lower pHs of 5.5-7.0, the logarithmic solubilities and dissolution rate constants increased linearly with decreasing pH with a slope of -1.0 and -0.95, respectively, indicating that Fe(OH) 2 + is the dominant dissolved ferric species. © 1993.
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Solubility and dissolution rate of colloidal r-FeOOH in seawater Reviewed
K. Kuma, S. Y. Suzuki, K. Matsunaga
Water Research 27 ( 4 ) 651 - 657 1992.11
Language：English Publishing type：Research paper (scientific journal)
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Existence of stable Fe(II) complex in oxic river water and its determination Reviewed
Y. Suzuki, K. Kuma, I. Kudo, K. Hasebe, K. Matsunaga
Water Research 26 ( 11 ) 1421 - 1424 1992.11
Language：English Publishing type：Research paper (scientific journal)
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Dissolution rate and solubility of colloidal hydrous ferric oxide in seawater Reviewed
共著者：K. Kuma, S. Nakabayashi, Y. Suzuki, K. Matsunaga
Marine Chemistry 38 ( 1-2 ) 133 - 143 1992.6
Language：English Publishing type：Research paper (scientific journal)
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Stabilization and determination of Fe(II) in seawater and its concentration in Harimanada Reviewed
Y. Suzuki, S. Nakabayashi, K. Kuma, I. Kudo, K. Matsunaga
Bulletin of Japanese Society of Fisheries and Oceanography 56 ( 3 ) 271 - 275 1992.3
Language：English Publishing type：Research paper (scientific journal)
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Photo-reduction of Fe(III) by dissolved organic substances and existence of Fe(II) in seawater during spring blooms Reviewed
K. Kuma, S. Nakabayashi, Y. Suzuki, I. Kudo, K. Matsunaga
Marine Chemistry 37 ( 1-2 ) 15 - 27 1992.3
Language：English Publishing type：Research paper (scientific journal)
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Uptake rate of iron by macroalgae from Sea of Japan(Laminaria religiosa Miyabe and Undaria pinnatifida) Reviewed
K. Matsunaga, Y. Suzuki, K. Kuma, I. Kudo, S. Nakabayashi
Bulletin of Japanese Society of Fisheries and Oceanography 55 ( 4 ) 349 - 353 1991.4
Language：English Publishing type：Research paper (scientific journal)