东江流域典型乡镇饮用水源地重金属污染健康风险评价

为阐明东江流域典型乡镇饮用水源地重金属污染物的分布特征与风险水平,对研究区域内9个区县45个水样中的常规水质指标和铁、铜、锰、锌、砷、铬、汞、铅、镉等金属污染物浓度进行了分析检测,并应用美国环境保护署推荐的环境健康风险评价模型,对不同类型的水源地进行了健康风险评价.结果表明,该研究区域的金属致癌风险较高,其中最高的致癌风险来自水库中的铬,成人和儿童分别达到1.14×10-4.a-1和2.14×10-4.a-1,江河、水库和地下水的金属总致癌风险超过了ICRP推荐的可接受风险水平5.0×10-5.a-1;该区域金属非致癌风险较低,均在EPA推荐的可接受范围内.该研究区域金属污染物的优先控制顺序为铬>砷>铅>铁>锌,饮用水源地的风险值排序为水库>江河>地下水>山泉.

Health Risk Assessment of Heavy Metals in Typical Township Water Sources in Dongjiang River Basin

In order to clarify the distribution characteristics and risk levels of heavy metals in typical drinking water sources of towns in Dongjiang River Basin, several regular water quality indexes as well as concentrations of Fe, Cu, Mn, Zn, As, Cr, Hg, Pb and Cd were analyzed in the 45 random water samples of 9 towns in the study area. The risk assessment was conducted according to different drinking water types using the environmental health risk assessment model recommended by U. S. EPA. The results indicated that the metal carcinogenic risk is relatively high in this area. The highest carcinogenic risk was from Cr in reservoir water, with the risk for adult people reaching 1.14×10^-4·a^-1 and the risk of children reaching 2.14×10^-4·a^-1. Total carcinogenic risk of reservoir, river and underground water exceeded the accepted level of 5.0×10^-5·a^-1 as suggested by ICRP while all the non-carcinogenic risk levels were within the acceptable range. The primary control sequence of metal pollution in this area was Cr>As>Pb>Fe>Zn; the risk value of different drinking water sources descended in this order: reservoir>river>underground water>mountain spring.