沈阳市典型城市河流优先控制污染物筛选及生态环境风险评估

细河和蒲河接纳了沈阳市工业废水的排放，水体中有毒、有害污染物不容忽视.为了明确河流中优先控制污染物，评价实际暴露水平下优先控制污染物对该水系生态环境的风险，选择细河和蒲河表层水为研究对象，开展了平水期、丰水期和枯水期的采样及有机污染物的检测分析；通过改进的潜在危害指数法对水体中检出的52种有机污染物打分排序，筛选了优先控制污染物；将效应评价外推法与商值法结合评价了优先控制污染物的生态环境风险.结果表明:52种有机污染物在细河中检出的平均质量浓度范围为9.20×10-6~1.37×10-1 mg/L，在蒲河中检出的平均质量浓度范围为4.30×10-6~3.03×10-2 mg/L.细河或蒲河中这些污染物的危害指数总分值（R）在22分以上的分别有12和13种，其中，PAEs（酞酸酯类）占6种，苯酚类污染物占4种.在细河中，DBP（邻苯二甲酸二丁酯）、苯酚、对甲基苯酚、2，4-二甲基苯酚和2，4，6-三甲基苯酚的R_q（风险商）>1，表明这些污染物存在较大的生态环境风险；在蒲河中，DBP、DEHP邻苯二甲酸二（2-乙基己基）酯]和苯酚的R_q>1，表明这些污染物存在较高生态环境风险水平.研究显示，在细河、蒲河中PAEs和苯酚类有机物为优先控制污染物，其中部分优先控制污染物具有较高的生态环境风险，可为该流域有毒、有害物污染控制方案的制定提供参考和指导. 

Priority Pollutants and Their Ecological Risk in Typically Urbanized River of Shenyang

In recent years, the water quality (indicated by COD, BOD and NH₃-N) in Liao River Basin (LRB) has been improved year by year, however, there have been more concerns regarding the level and ecological risk of trace toxic substances in the water bodies. The Xi and Pu Rivers are typically urbanized rivers in Shenyang City, receiving the effluences from industrial wastewaters, which led to contamination of the water bodies by toxic and hazardous substances. The objectives of this study are to identify the priority pollutants in the rivers and to assess the ecological risk of the pollutants. The surface waters were collected from the Xi and Pu Rivers during the normal, wet and dry seasons, sequentially, 52 organic pollutants in the rivers were detected. By the method of improved potential hazardous index, these organic pollutants were scored and sequenced for screening the priority pollutants. Using the extrapolation method of effect evaluation coupled with the risk quotient (R_q) approach, the ecological risk of the priority pollutants was assessed. The results showed that the average concentrations of 52 organic pollutants were in the range of 9.20×10^-6-1.37×10^-1 mg/L in the Xi River and 4.30×10^-6-3.03×10^-2 mg/L in the Pu River. Thirteen or twelve of 52 organic pollutants in Xi or Pu Rivers had a total score of the potential hazardous index over 22, including 6 phthalic acid esters (PAEs) and 4 phenols. The R_q values of dibutyl phthalate (DBP), phenol, 4-methylphenol, 2,4-dimethylphenol and 2,4,6-trimethylphenol in the Xi River, and those of DBP, diphenyl phthalate (2-ethylhexyl) ester (DEHP) and phenol in the Pu River were higher than 1. Those results indicated that PAEs and phenols were identified as the priority organic pollutants, some of them showing relatively high ecological risks. Those results provide not only a theoretical basis for the formulation of pollution control countermeasures and management schemes for the whole river basin and the typical river section, but also data support for the treatment technology of the emission point source.