淮南市不同功能区叶面尘和地表灰尘中重金属分布特征、来源及健康风险评价

以淮南市叶面尘及对应地表灰尘为研究对象,采集了6个不同功能区的石楠叶面尘和相应地表灰尘,研究了Cr、Cu、Zn、Pb、As、Ni、V的分布特征及其来源,并采用美国EPA人体暴露风险评价模型,对不同功能区、不同暴露途径的儿童重金属致癌和非致癌健康风险进行评估.结果表明:淮南市叶面尘中重金属含量显著高于地表灰尘,叶面尘主要污染元素为Zn、Pb、Cu、As、Ni,地表灰尘中主要污染元素为Cu、Zn、Pb.不同功能区重金属来源存在差异,商业交通区、经济开发区和煤炭运输区,交通排放是其主要来源,文教区、公园绿地、居住区来源较为复杂,除来自于交通排放,还可能来自于工业排放、燃煤燃烧、炊事活动和公共设施的磨损.叶面尘和地表灰尘中Ni、As、Cr的致癌风险均小于安全阈值,地表灰尘中非致癌总风险为0.58,叶面尘为1.36,超出了安全阈值1.0,已经对儿童健康构成危害,手-口摄入是主要暴露途径;各功能区叶面尘重金属非致癌风险除煤炭运输区外,均大于1.0,排序为:文教区公园绿地居住区经济开发区商业交通区煤炭运输区,地表灰尘均小于1.0,排序为:公园绿地经济开发区文教区商业交通区煤炭运输区居住区.叶面尘中重金属的非致癌风险排序为:AsPbCrVNiCuZn,地表灰尘为:AsCrPbVCuNiZn.

Distribution, sources and health risk assessment of heavy metals in foliar and surface dust of different functional areas of Huainan City

This study was focused on the distribution and sources of Cr, Cu, Zn, Pb, As, Ni and V in the foliar dust (Photinia serrulata Lindl) and the surrounded surface dust in six different functional districts of Huainan, a typical coal mine city in Anhui Province, East China. The carcinogenic and non-carcinogenic risks of heavy metals to children were also evaluated by using US EPA human exposure risk assessment model. Contents of heavy metals in foliar dust were found to be significantly higher than those in the surface dust. The main pollution elements in foliar dust were Zn, Pb, Cu, As, Ni and in surface dust were Cu, Zn and Pb. The sources of heavy metals varied in different functional districts. Traffic emission was the main source in commercial traffic district, economic development district and coal transportation district, while the sources in cultural and educational district, parks and greenery district, and residential districts were more complex including traffic emission, industrial emission, coal burning, cooking activities and wear of public facilities. The carcinogenic risk indices of Ni, As, and Cr were under the safety threshold. Total non-carcinogenic risks was 0.58 in surface dust and 1.36 in foliar dust. The latter exceeded the safety threshold of 1.0 and have constituted a hazard to children health. Except coal transportation district, the non-carcinogenic hazard indices of heavy metals in foliar dust in all functional districts were greater than 1.0 and decreased in the order of cultural and educational district > parks and greenery district > residential district > economic development district > commercial traffic district > coal transportation district. The hazard indices of surface dust were less than 1.0, decreasing in the order of parks and greenery district > economic development district > cultural and educational district> commercial traffic district > coal transportation district > residential district. Non-carcinogenic risk of heavy metals in foliar dust followed in the order of As > Pb > Cr > V > Ni > Cu > Zn, and followed in the order of As > Cr > Pb > V > Cu > Ni > Zn in surface dust.