天津城市公园灰尘重金属污染健康风险评价

Health risk assessment on heavy metals in dust of urban parks in Tianjin

分析了天津市中心城区41个代表性公园灰尘样品的重金属含量,借助健康风险评价模型,对天津市公园灰尘重金属的污染状况进行了健康风险评价。结果表明,天津市公园灰尘在不同程度上受到了重金属Cu、Pb、Cr、Cd和Ni的污染,其中,重金属Cu、Pb、Cr、Cd和Ni的含量平均值分别为113.18、63.32、103.18、1.14和40.58 mg·kg-1,均高于天津市土壤重金属元素的背景值。健康风险评价模型计算表明,人体经手-口接触行为直接摄入是公园灰尘暴露风险的主要途径,重金属日平均暴露剂量依次为手-口直接摄食剂量>皮肤吸收剂量>呼吸道吸入剂量。本研究的5种重金属元素对人体造成的慢性非致癌风险值依次表现为:Cr>Pb>Cu>Ni>Cd,对人体不会造成危害,儿童的非致癌风险大于成人。致癌重金属的致癌风险依次为Ni>Cr>Cd,均低于癌症风险阈值,尚未形成致癌风险。

Samples of surface dust were collected from 41 representative urban parks in Tianjin. The health risk of heavy metals in surface dust was evaluated using human health risk assessment model established by U.S. EPA. The results showed that the pollution of heavy metals was seri- ous. The average concentrations of Cu, Pb, Cr, Cd and Ni in the samples were 113.18, 63.32, 103.18, 1.14 and 40.58 mg· kg-1 respectively, which all exceeded the background values in the soils of Tianjin. The direct ingestion of dust via hand-mouth contact behaviors was the major exposure pathway for health risk and the amount of chronic daily average exposure was in order of hand-mouth direct ingestion 〉 dermal uptake 〉 inhalation. The non-cancer risk of exposure was Cr 〉 Pb 〉 Cu 〉 Ni 〉 Cd, while the cancer risk of exposure was Ni 〉 Cr 〉 Cd. Non-cancer risk was higher for children than for adults. All the risks were lower than the average risk thresholds of the heavy metals, and would not cause non-carcinogenic or carcinogenic health hazard to hu- man body, while its potential ecological hazard on children should be considered.