【摘要】 上海市河网密布,城区河道有机污染严重,受沿线雨、污水排水系统影响,中小河道常出现阶段性黑臭,增加了水体污染程度及水媒病原体传播的可能性。为评估雨水排水系统对受纳河道主要微生物指标影响程度,以上海市中心城区受泵站放江影响程度不一的2条景观河段为例,在晴天、旱天放江、雨天放江、雨后4种工况下,调查分析了景观河道微生物污染特征。结果表明,晴天时受纳河道细菌总数在104CFU/m L以上,与同区域公园河道在1个数量级上,属于不清洁水体;大肠菌群数量为103CFU/m L,远高于公园河道;在旱天放江期间,受河道水动力条件影响,仅泵站排放口附近细菌与大肠菌群数量大幅增加;雨天放江期间,受纳河道细菌总数达到106CFU/m L以上,比公园河道高1个数量级;大肠菌群数量为105CFU/m L,大大超过景观娱乐用水的水质需求。公园河段在降雨后水体微生物能较快降低,而受纳河道在降雨放江停止24 h后,其微生物浓度依然较高。地表径流、汇水区雨污混接、用地类型的不透水化及河道水动力条件可能是受纳河道微生物污染程度高的主要原因。作为景观水体,即便不直接接触,也存在潜在健康风险,需要加强对河道微生物污染的治理。更多还原

【Abstract】 Urban rivers have become widely polluted as a result of industrialization and urbanization. They receive water from domestic waste water and heavy rainfalls lead to combined sewer overflows that increase organic pollution. Microbial indicators play an important role in water quality assessment. Total bacteria( TB) and total coliforms( TC) were chosen as indicator microorganisms in this study for assessing the influence of water discharged from pumping stations on urban rivers,during rainfall events and in dry weather. The results provide technical support and reference for water quality monitoring and risk management. Two river reaches were selected for this study: one receiving water from a pumping station and the other flowing through a park that does not. Water samples were collected at four sites: Site A,500 m above the pumping station outfall; Site B,20 m below the outfall; Site C,500 m below the outfall; Site D,in the park river. Surface water samples were collected in the summer of 2015 under four conditions: sunny,without discharge from the pumping station and at least three days after the last rain;sunny with water discharge from the pumping station and at least three days after the last rain; rainy with discharge from the pumping station; 24 hours after rain with discharge from the pumping station. Water samples were divided into two groups,one for determining water quality parameters( BOD5,CODMn,TNTP,NH3-N and SS) and the other group was for determining bacteria( TB and TC). All analyses were run in triplicate with a control. Microbial contamination was found to be serious with severe organic and nutrient pollution of receiving water. Concentrations of TB and TC in the receiving river ranged,respectively,from 104 CFU / m L to 106 CFU / m L and from 103 CFU / m L to 105 CFU / m L. Both TB and TC in the receiving river were an order of magnitude higher than in the park river.Microorganism concentrations in the park river declined quickly after a rain event,while concentrations in the receiving stream remained high 24 hours after rain and water discharge from the pumping station had ceased. At the three sampling sites( above,near and below the outfall) of the receiving river,TB and TC concentrations all exceeded water quality standards for recreation,caused by surface runoff,combined sewage flows,land use type and river hydrology. In urban waters,even if there is not direct contact,the prevention and control of microbial health risksshould be given more attention.更多还原