渭河干流浅层地下水与地表水中重金属Cd污染特征及风险评价

为了解渭河流域水体重金属污染现状及健康危害风险,沿渭河干流采集浅层地下水和地表水水样,采用单因子指数法和美国环境保护署(USEPA)健康风险评价模型揭示了水体中重金属Cd污染现状和健康风险。结果表明:2018年渭河干流地下水和地表水中Cd浓度分别为426.40~1104.27 ng·L^-1和224.70~1154.12 ng·L^-1;参照《地下水质量标准》(GB/T 14848-2017)和《地表水环境质量标准》(GB 3838-2002)得知,地下水和地表水中Cd浓度均在GB/T 14848—2017和GB 3838-2002Ⅰ~Ⅲ类标准限值内;水体中Cd浓度表现出明显的空间分异性,沿河流流向均表现为逐渐增加的趋势;地下水与地表水中Cd浓度高值区相一致,即集中分布于陕西省兴平市和渭南市临渭区;由水体中Cd浓度单因子指数评价结果可知,渭河干流水体中Cd污染属于清洁水平;沿河流流向,渭河中游和下游水体中Cd浓度单因子污染指数远高于上游;水体中重金属Cd对成人和儿童产生的致癌风险分别为(1.48~2.05)×10^-4和(1.84~2.55)×10^-4,说明水体中Cd对人体可能会产生一定的健康风险。

Characteristics and Risk Assessment of Heavy Meatal Cd Pollution of Shallow Groundwater and Surface Water in Main Stream of Weihe River,China

In order to understand the current status of heavy metal pollution and health risk of water in Weihe river,the samples of shallow groundwater and surface water were collected,and the single factor index and USEPA health risk assessment model were used to reveal the current status and health risk of heavy metal Cd pollution of water in main stream of Weihe river.The results show that Cd concentrations of groundwater and surface water in main stream of Weihe river in 2018 are 426.40-1104.27 ng·L^-1 and 224.70-1154.12 ng·L^-1,respectively;according to Standard for Groundwater Quality(GB/T 14848-2017)and Environmental Quality Standards for Surface Water(GB 3838-2002),the Cd concentrations of groundwater and surface water are within the limits of classes Ⅰ-Ⅲ;the Cd concentrations show obvious spatial differentiation,and a gradual increase along the river flow direction;the high value areas of Cd concentrations in groundwater are consistent with that in surface water,which are Xingping city and Linwei district of Weinan city,Shaanxi province;according to the evaluation results of Cd concentrations based on single factor index,the Cd pollution is close to the clean level;along the river flow direction,the single factor index of Cd pollution in the middle and lower part of Weihe river is much higher than that in the upper part of Weihe river;the carcinogenic risk values of heavy metal Cd to adults and children are(1.48-2.05)×10^-4 and(1.84-2.55)×10^-4,respectively,so that Cd in water maybe have health risk for human.