福建九龙江流域重金属分布来源及健康风险评价

摘要

Seven heavy metals (Zn Cu As Cr Pb Ni and Cd) were investigated for their concentration and distribution in the Jiulong River where 27water samples were collected in its mainstream. The main source of these heavy metals were speculated using the factor analysis, and relevant health risk were assessed using water pollution index and USEPA health risk assessment model. The results showed that the average concentrations of As exceeded the relevant standards and the exceeding standard rate was 14.81%. Spatial structure analysis indicated that areas of over-standard heavy metal were mainly in the downstream and estuary of the basin. The results of factor analysis indicated that the source of As, Cr, Cu and Ni were mainly from various human activities;the content of Cd, Pb and Zn were mainly affected by the soil parent material, geochemistry effects and cultivation. It was indicated that health risks of carcinogenic heavy metals via drinking water ingestion were higher than those of noncarcinogenic metals and, heavy metal pollution would lead to high potential health risks especially for children. The health risks caused by the carcinogenic metals (Cr and As) were significantly higher than the maximum allowance levels recommended by ICRP(5×10-5a-1). Among the noncarcinogens, the highest risk was associated with Cu, followed by Pb, Zn and Ni. The noncarcinogenic risks ranged from 10-9 to 10-10a-1, much lower than the maximum allowance level recommended by ICRP.%为研究九龙江流域水体重金属污染水平,在其主要干流及支流采集27个表层水样,分析了Zn、Cu、As、Cr、Pb、Ni和Cd共7种重金属的含量及空间分布特征,利用因子分析方法分析重金属污染物的主要来源,并采用美国环保局推荐的健康风险评价模型对其所引起的健康风险作了初步评价.结果表明,流域水体中Zn的平均浓度最高,为154.893µg/L；As超过地表水Ⅲ类水质标准,超标率为14.81%,超标区域集中位于九龙江下游及河口区.因子分析表明,As、Cr、Cu和Ni的来源主要受各种人为活动影响,Cd、Pb和Zn的来源与成土母质、地球化学作用和农业生产活动有密切的关系.健康风险评价表明,化学致癌物对人体健康危害的个人年均风险远远超过非致癌物的年风险,儿童比成人更易于受到重金属污染的威胁.致癌物Cr和As的个人年均风险值都大于国际辐射防护委员会(ICRP)推荐的最大可接受风险水平5.0×10-5a-1,其中 Cr>As；非致癌有毒化学物质通过饮水途径所引起的健康危害的个人年均风险大小为 Cu>Pb>Zn>Ni,四者风险水平在10-9~10-10a-1之间,均低于ICRP标准4~5个数量级.