Papers - SUZUKI Yoshihiro
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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)