河北省永清县地下水重金属来源识别及健康风险评价

Source Identification and Health Risk Assessment of Heavy Metals in Groundwater of Yongqing County,Hebei Province

永清县是京津冀地区最大的无公害蔬菜种植基地,主要灌溉用水和部分生活用水取自地下水。为全面掌握永清县地下水重金属含量特征、空间分布模式、污染来源及可能引起的健康风险,在全县范围内系统采集370件地下水样品,并对Cu、Pb、Zn、Cd、Ni、Hg和As共7种重金属元素进行了分析测试。根据分析结果,研究区部分地下水样品中Pb、Cd、Ni和As浓度超出Ⅲ类水质标准限值(GB/T 14848—2017),部分样品Pb、Cd和Ni浓度高于农田灌溉水质标准限值(GB 5084—2021),超标点位主要位于研究区中部和南部。根据主成分分析结果,研究区地下水中As和Cd主要与农业生产有关,Cu、Zn、Ni和Pb主要来自交通运输和农业生产,Hg主要受自然背景影响。致癌重金属(Cd和As)引起的健康风险高于非致癌重金属(Cu、Pb、Zn、Ni和Hg),Cd和As是引起健康风险的主要重金属元素,在健康风险总值中所占比例分别为79.24%和20.66%。地下水重金属元素健康风险高值区主要集中于研究区东南部,部分采样点位的健康风险值超过了最大可接受水平,因此应合理规划研究区地下水安全利用,并采取有效措施降低地下水中重金属引起的健康风险。

Yongqing County is the largest“Pollution-Free”vegetable planting base in the Beijing-Tianjin-Hebei region,China.The vast majority of irrigation water and some domestic water is taken from groundwater in Yongqing.In order to comprehensively evaluate the content of heavy metals in groundwater and the possible health risks,370 groundwater samples were systematically collected throughout the county,and seven heavy metal elements including Cu,Pb,Zn,Cd,Ni,Hg and As were analyzed.It is found that the content of Pb,Cd,Ni and As in some groundwater samples exceeded the water quality standard of classⅢ(GB/T 14848-2017),and the content of Pb,Cd and Ni in some samples were higher than the water quality standard of farmland irrigation(GB 5084-2021).The sampling points with high heavy metal contents are mainly located in the central and southern parts of the study area.According to the principal component analysis,As and Cd in groundwater are mainly related to agricultural production,while Cu,Zn,Ni and Pb are mostly from transportation and agricultural production,and Hg is mainly affected by natural background.The health risks caused by carcinogenic heavy metals(Cd and As)are higher than those caused by non-carcinogenic heavy metals(Cu,Pb,Zn,Ni and Hg).Cd and As are the main heavy metals that cause health risks,accounted for 79.24%and 20.66%of the total health risk,respectively.The health risk value caused by heavy metals in groundwater exceeds the maximum acceptable level.Therefore,the groundwater safety in the study area should be reasonably planned,and effective measures should be taken to reduce the health risks caused by heavy metals in groundwater.