北京城区土壤与灰尘中重金属的健康风险评价

选择北京市城区公园广场、大学校区、商业区和居民小区等市民日常活动区域，采集地表土壤及灰尘样品，分析重金属种类及其浓度。采用单因子指数法和Nemerrow指数法，研究了各功能区不同重金属的污染程度，并采用美国环保总署健康风险评价模型，计算北京市居民经呼吸途径和皮肤接触途径摄入重金属而引起的健康风险。研究结果表明，北京市城区人口活动密集区域地表灰尘重金属污染较为严重，Cu、Pb和Zn质量分数的平均值分别为北京市土壤背景值的2~3倍，其中西单灰尘中Zn的质量分数达528mg/kg，超过背景值9倍以上。健康风险评价模型计算结果表明，人体重金属摄入途径风险大小为：呼吸途径>皮肤接触途径；重金属对人体非致癌风险大小为 Pb>Cu>Zn；在不同功能区之间非致癌风险大小为公园广场>大学校区>居民区>商业区。因非致癌风险指数小于阈值1，所以北京市地表灰尘中的重金属，在目前尚不至引起严重的健康风险。

Health risk assessment of heavy metals in dust and soil samples from Beijing

Samples of soil and surface dust were collected from parks, universities, residential areas and commercial districts in Beijing. The pollution index and Nemerrow integrated pollution index were used to indicate the extent of heavy metal pollution. The health risk assessment model recommended by the US EPA was used to calculate the intake of heavy metals by residents through inhalation and skin exposure. The results indicated that the average mass fraction of Cu, Zn, and Pb are 2-3 times higher than the soil background values in Beijing. In particular, the dust mass fraction of Zn is as high as 528mg/kg, which is nine times the background value. It was concluded that intake of heavy metal through skin exposure is greater than by inhalation. The non-cancer risk index of different heavy metals decreases in the order Pb > Cu > Zn. The non-cancer risk in different areas of Beijing decreases in the order parks > universities > residential areas > commerical districts. It was also shown that the non-cancer risk value is less than 1, indicating a relatively low health risk.