苏南农村地区土壤、大米和井水重金属污染现状

摘要:目的 了解苏南农村地区土壤、大米等重金属污染情况。方法 采用分层整群抽样方法，在苏南农村东、南、西、北、中5个方位及市区采集环境及食物样品，用ICP-MS检测其中重金属含量。结果 18份土壤样品重金属Cd、As、Pb平均含量为（1.150±0.860）mg/kg，（46.232±40.313）mg/kg，（55.855±32.690）mg/kg，超标率分别达77.78%、38.89%和27.78%，Cr、Hg含量均低于限值；内梅罗污染指数评价显示，苏南农村土壤整体达轻度污染，其中2、5号点土壤达重污染，1号点达中污染，其余各点土壤重金属污染已处警戒范围。井水、大米中重金属低于GB5749-2006和GB2715-2005标准限量。结论 苏南农村地区井水、大米尚未受Cd、As、Pb、Cr、Hg 5种重金属污染，但土壤已不同程度受到Cd、As、Pb污染，Cd＞As＞Pb,应引起重视。

Survey on the status of heavy metal contamination in soil,rice, and well water in rural areas of southern Jiangsu

Abstract:Objective The study aimed to assess the status of heavy metal contamination in soil, rice, and well water in rural areas of southern Jiangsu. Methods Environmental and food samples from east, south, west, north, and central rural areas, as well as downtown areas of southern Jiangsu were collected by stratified cluster sampling; and heavy metal content of the samples were measured by ICP-MS. Results The average contents of cadmium (Cd), arsenic (As), and lead (Pb) of 18 soil samples were 1.150±0.860 mg/kg, 46.232±40.313 mg/kg, and 55.855±32.690 mg/kg, with the non-compliance rates reaching 77.78%, 38.89%, and 27.78%, respectively. The contents of chromium (Cr) and mercury (Hg) were lower than the standard limits. Evaluation of the Nemerow pollution index showed that soil in rural southern Jiangsu was mildly contaminated, wherein soil in sites 2 and 5 was heavily contaminated, soil in site 1 was moderately contaminated, and heavy metal contamination of soil in the remaining sites had fallen within the warning limits. Heavy metal contents in well water and rice samples were below the GB5749-2006 and GB2715-2005 standards. Conclusion Well water and rice in rural southern Jiangsu remain free of contamination by Cd, As, Pb, Cr, and Hg. However, soil in the area has been subjected to different levels of Cd, As, and Pb contamination (Cd＞As＞Pb), suggesting that prevention of heavy metal contamination in the area should be emphasized.