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标题：River Flows Influence on Nutrients (Si, N and P) and Fecal Coliforms (E. coli) in Two Tributaries of the Estuarine Channel of Bertioga (Santos Estuary, São Paulo, Brazil)
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作者：Bruno Otero Sutti ; Luciana Lopes Guimarães ; Roberto Pereira Borges 等
期刊名称：Journal of Geoscience and Environment Protection
印刷版ISSN：2327-4336
电子版ISSN：2327-4344
出版年度：2022
卷号：10
期号：6
页码：26-46
DOI：10.4236/gep.2022.106003
语种：English
出版社：Scientific Research Pub
摘要：Sewage introduction into rivers has altered the physical and chemical properties of waters and also the microbial metabolism. This study aimed to evaluate the Escherichia coli and nutrient concentrations in the Maratuã and Crumaú rivers (Santos Estuary, Brazil) during two periods with distinct magnitudes of freshwater runoff, verifying possible relation of abiotic changes with the microbial metabolism. Water sampling was performed in October/2012 (dry season) and January/2013 (rainy season) at two points in the Crumaú river (upstream and downstream zone) and one in the Maratuã river (downstream zone). The water subsamples were obtained for E. coli and nutrient analyses while the velocity of water flow, water level, temperature, salinity, and dissolved oxygen were measured in situ. The E. coli concentrations were under the detection limit in the Maratuã downstream during the dry season reaching a maximum value (1.47 × 104 CFU/100mL) in the Crumaú upstream during the rainy season. E. coli presented strong positive correlation with nutrients (ammoniacal-N and phosphate), evidencing the sewage source in the Crumaú upstream shown by this association. In both periods, the low oxygen saturation (<50%) and high ammoniacal-N concentrations (>100 μmol·L-1) indicated considerable predominance of heterotrophic metabolism in the Crumaú upstream. The low dissolved oxygen values in Crumaú River are corroborated to show a low self-depuration capacity in the rainy period due to maintenance of high nutrient and E. coli at two points in the Crumaú river (upstream and downstream zone) and one in the Maratuã river (downstream zone). Besides, these results evidenced that the tendency of the metabolism changed from autotrophic to heterotrophic under high river flow events at this studied estuarine sector located at Santos estuarine complex.
关键词：EutrophicationDomestic SewageWater QualitySeasonal PeriodEstuary