东莞市农业土壤和蔬菜砷含量及其健康风险分析

Arsenic Concentrations in Vegetables and Soils in Dongguan and Potential Risk to Human Health

研究系统采集了东莞市118个农业土壤样品和43个蔬菜样品进行砷含量分析,研究了土壤和蔬菜砷含量及其健康风险。研究发现,东莞市农业土壤砷含量变化范围0.40～28.87mg/kg,平均值12.95mg/kg,远高于东莞市背景值,其中62%的样品砷含量超过国家一级标准限定值,砷含量的变异系数为53.28%,变异程度较大。东莞市各区域土壤砷空间分布不均匀,土壤砷含量平均值大小排序如下:西部平原区>环境保护区>中部过渡区>东南丘陵区。土壤砷主要来源于成土母质,化石燃料燃烧、农药、化肥(磷肥)等工农业活动的输入也不容忽视。东莞市蔬菜砷含量超标比较严重,蔬菜砷对东莞市部分人群存在一定的健康风险。

Pollution caused by over-content of arsenic in soils and vegetables produced in Dongguan City, Guangdong Province was analyzed. In order to make assessment more objective and assurable, 118 agricultural soil and 43 vegetable samples were collected. Results showed that arsenic concentrations in soil ranged from 0.40mg/kg to 28.87mg/kg, with arithmetic mean of 12.95mg/kg, far higher than the background arsenic concentration of soil. 62% of soil samples exceeded the content of heavy metal in Environmental Quality Standard for Soils of GB15618-1995. The spatial distribution showed that arsenic contents of agricultural soils are greatly different in different areas, with the order as western plain area, protected area, central transition area and southeastern hilly area. The main source of arsenic is from soil parent materials, with sources also including combustion of fossil fuels, lead-contained pesticide and fertilizer. Arsenic concentrations in vegetable samples also revealed excessive when measured by Maximum Level of Contaminants in Foods of GB2762-2005. Consuming vegetables with elevated arsenic concentrations may pose a health risk to local residents, particularly the young, elderly or ill.