成都市地表灰尘重金属污染分布特征及健康风险评价

对成都市中心城区娱乐区、居民区、商业区和城市广场等日常活动区域代表点的地表灰尘中的重金属进行监测,分析其污染分布特征,并应用美国EPA人体暴露风险评价方法对地表灰尘进行了健康风险评价。结果表明,研究区域地表灰尘重金属污染较为严重,Pb、Zn、Cu、Ni、Cr、Cd的平均含量分别为成都市土壤背景值的1.18~77.57倍,其中Cd的富集因子大于10,污染极强且富集在颗粒物中。暴露模型计算表明,重金属慢性每日平均暴露量为手-口摄入量皮肤吸收量吸入空气量,经手-口接触行为是人体地表灰尘暴露风险的主要途径。儿童重金属非致癌风险CrPbCdCuZnNi,成人重金属非致癌风险PbCrCdCuZnNi,且均小于非致癌风险阈值1,不会对城市人群造成明显伤害。重金属致癌风险CrCdNi,均低于致癌风险阈值,表明不具有致癌风险,但潜在生态危害值得重视。

The Pollution State and Health Risk Assessment of Heavy Metals in Road Dust of Chengdu

Monitoring the heavy metals from the road dust samples which were collected covering the entertainment district, residential district, commercial district and city squares in Chengdu central area,finding out the spatial distribution of heavy metals in surface dust,and a further health risk assessment was carried out using USEPA Health Risk Assessment Model. The result showed that the heavy metal pollution in the research area was heavy, average concentrations of Pb, Zn, Cu, Ni, Cr and Cd were 1.18-77.57 times of background value of Chengdu, among which Cd is a high contaminative pollutant with a enrichment factor of 10, extremely easy attached to particles. Model showed the order of average daily chronic expose dosage was hand-mouth contact>skin absorb>breath, the major health risk was hand-mouth contact. Non-cancer hazard order for children was Cr>Pb>Cd>Cu>Zn>Ni while Pb>Cr>Cd>Cu>Zn>Ni for adults, of which all risks were lower than threadhold values. The order of cancer hazard was Cr>Cd>Ni, all lower than threadhold value, which indicated the adverse impact of heavy metals in dusts on civilians was relatively light in Chengdu.