会仙岩溶湿地水体金属元素分布与健康风险评价

Metal Distributions and Human Health Risk Assessments on Waters in the Huixian Karst Wetland, China

以我国最大的低海拔岩溶湿地会仙岩溶湿地为研究区域,对该区域内4种主要类型水(井水、地表河水、地下河水和溶潭水)的23组样品中9种金属元素(As、Cr、Al、Cu、Pb、Zn、Ni、Mn和Hg)进行检测和分析,运用多元统计方法和健康风险评价模型分别研究了9种金属元素在4种类型水中的浓度特征和健康风险.结果显示,会仙岩溶湿地水体中金属元素平均浓度顺序为Al>Mn>Zn>Cr>Ni>As>Hg>Cu>Pb,井水中Hg(1.08μg·L^-1)、地表河水中Hg(0.78μg·L^-1)和Mn(259.00μg·L^-1)以及溶潭水中Hg(0.47μg·L^-1)和Al(300.00μg·L^-1)的最大浓度已超过我国相应水质标准,地下河水样中未出现金属元素超标.从水体中金属元素角度,井水和地下河水质总体优于地表河水和溶潭水.井水中Cr、Ni、Cu和Zn浓度主要与地质背景值有关,溶潭水中Al和Pb浓度主要受北部硫铁矿开采和居民活动影响,河流中As和Mn浓度可能受旅游活动、渔业养殖和河道底泥综合影响.健康风险评价结果显示,4种类型水中9种金属元素通过饮用水途径和皮肤入渗途径引起的年均总健康风险顺序为井水>地下河水>溶潭水>地表河水,井水中金属元素通过饮用水途径对成人(6.11×10-5 a-1)和儿童(6.67×10-5 a-1)引起的年均总健康风险值已超过最大可接受风险水平(5.0×10-5 a-1).Cr是引起年均致癌健康风险的主要金属元素.从饮用水安全角度,在饮用前需对井水中的Hg和Cr污染物进行适当控制.

The concentrations of nine metals(As,Cr,Al,Cu,Pb,Zn,Ni,Mn,and Hg),in 23 water samples collected from four main types of water(well,surface river,subterranean stream and blue hole),in the Huixian karst wetland were determined and analyzed to investigate their distributions and health risks.A multivariate statistical analysis was used to study the distribution characteristics of the metals.A human health risk assessment model was developed to assess the health risks.The results found that the mean concentrations of metals in water from the Huixian karst wetland were in the order:Al>Mn>Zn>Cr>Ni>As>Hg>Cu>Pb.The maximum concentrations of Hg(1.08μg·L^-1)in the well water,Hg(0.78μg·L^-1)and Mn(259.00μg·L^-1)in the surface river water,and Hg(0.47μg·L^-1)and Al(300.00μg·L^-1)in the blue hole water all exceeded the corresponding standard limits.The metal concentrations in the subterranean stream samples were all within the regulated limits.For the nine metals,the well water and the subterranean stream water qualities were better than those of the surface river and the blue hole.The results of the multivariate statistical analysis showed that the concentrations of Cr,Ni,Cu,and Zn in the well water were mainly related to the regional geological background,while the concentrations of Al and Pb in the blue hole water were mainly affected by pyrite mining and residential activities.The concentrations of As and Mn in rivers may be affected by tourism activity,aquaculture and river sediments.The results of the health risk assessment on water through the drinking and skin penetration pathway indicated that the total health risks order was:well>subterranean stream>blue hole>surface river.The total health risks values of well water as drinking water for adults(6.11×10-5 a-1)and children(6.67×10-5 a-1)exceeded the maximum allowance level(5.0×10-5 a-1).Cr was the main metal element that causes carcinogenic risks.For drinking water safety,the concentrations of Hg and Cr in well water should be controlled before drinking.