扑草净水环境质量基准及风险评估

Derivation of water quality criteria and ecological risk assessment for prometryn

选择田间使用量大的扑草净为研究对象,分析了扑草净在南四湖流域地表水中的空间分布,推导了扑草净的水质基准,通过定性与定量风险评估方法评估了扑草净的生态风险.结果表明,南四湖流域28个地表水采样点中扑草净浓度为0~667.7ng/L,平均值为69.2ng/L.搜集筛选了15种水生生物慢性毒性数据,利用物种敏感度分布法,推导出扑草净的水质基准为82.4ng/L.使用商值法评估南四湖流域生态风险,结果表明,扑草净生态风险最高区域位于NS09,主要来源是地表径流与雨水冲刷.采用联合概率曲线法进一步分析生态风险,发现南四湖水体中扑草净对1%~5%的水生生物产生危害的概率为11.2%~6.4%.总体来看,南四湖流域扑草净的生态环境风险处于较低水平.

In this study,concentrations of prometryn in surface water collected from the Nansi Lake basin were analyzed,WQC of prometryn was derived,and qualitative and quantitative risk assessment methods were conducted to assess the risk of prometryn to aquatic species.Results showed that concentrations of prometryn in 28 sampling sites were in the range of 0 to 667.7 ng/L,with an average of 69.2 ng/L.From the Chronic toxicity analysis of the 15 species of collected and screened aquatic organisms,the Navicula pelliculosa appeared to be the most sensitive species,which could be used as a biological indicator for prometryn pollution in aquatic environment.The species sensitivity distribution(SSD)method was applied to derive WQC for prometryn,which was 82.4 ng/L.Meanwhile,the sampling site NS09 was the highest risk area based on the result of the hazard quotient method.The joint probability curve method indicated that ecological risks might exist 6.4%and 11.2%of surface water,while 5%threshold(HC5)and 1%threshold(HC1)were set up to protect aquatic species,respectively.Generally,prometryn posted a low risk to the aquatic organisms in the Nansi Lake basin.We hope that this work could provide valuable information for the management and control of prometryn pollution.