北京城市广场及校园表土(灰尘)中重金属水平与健康风险

通过对北京市城市广场和学校表层土壤与相应的地表灰尘中重金属含量调查,探讨土壤与灰尘之间元素分布的差异及来源,评估青少年在校期间通过灰尘摄入重金属的健康风险。研究表明:城市广场和校园土壤中Cu、Pb和Zn、灰尘中As、Cu、Pb、Zn和Cd显著高于北京市土壤重金属背景值,土壤(灰尘)中As、Ni、Cu、Pb、Zn和Cd超过背景值的样本比率分别为67%(27%)、13%(63%)、83%(100%)、73%(100%)、83%(100%)和53%(100%)。土壤中Cu、Pb和Zn存在一定积累,灰尘中Cd、Cu、Pb和Zn积累较重。灰尘中Cu、Pb和Zn显著高于土壤。校园土壤中Ni显著高于城市广场土壤,其他元素两者之间差异不大;校园灰尘中Ni、Pb和Zn显著高于城市广场。中学生通过校园灰尘摄入没有导致明显的健康风险。

Concentrations and risk of heavy metals in surface soil and dust in urban squares and school campus in Beijing

Heavy metals pollution of soils is a major environmental problem. Heavy metals in urban soils could cause deleterious effects on human health by contacts with skin and intakes unconsciously. Soil and dust samples in squares and school campus in Beijing were collected for assessing the concentrations and health risks of heavy metals. The results showed that the concentrations of heavy metals in the soils and dusts presented a lognormal distribution. The concentrations of Cu, Pb and Zn in soils, As, Cu, Pb, Zn and Cd in dusts were all higher than the background concentrations of soils in Beijing, and 67% (27%), 13% (63%), 83% (100%), 73% (100%), 83% (100%) and 53% (100%) of the soils (dusts) samples exceeded the background values of soils in Beijing for As, Ni, Cu, Pb, Zn and Cd, respectively. Relatively speaking, Zn was accumulated in soils, while Cd, Cu, Pb and Zn were accumulated in dusts. The concentrations of Cu, Pb and Zn in dusts were significantly higher than in soils. The concentrations of Ni, Pb and Zn in dusts in school campus were significantly higher than in squares. There are no significant health risks of heavy metals from dusts in school campus.