南昌市道路尘PM2.5中重金属分布特征及健康风险评价

Characteristics and health risk assessment of heavy metals in PM2.5 fraction of road dust in Nanchang City

为了解南昌市道路尘PM2.5中重金属元素的分布特征和健康风险,利用颗粒物再悬浮采样器采集了道路尘中的PM2.5样品,用电感耦合等离子体质谱仪和原子荧光光谱仪测定了样品中11种重金属元素的含量.结果表明,道路尘PM2.5中Mn、Zn、Cr、Cu、Pb、V、As、Ni、Co、Cd和Hg的平均含量分别为1014、208.17、106.47、102.40、62.12、39.59、28.93、24.07、7.86、0.58、0.53 mg·kg-1,除V和Co外均大于南昌市土壤元素背景值,整体上次干道和支路的金属含量会高于主干道重金属的含量,比国内外其他城市相对要低.地累积指数结果显示,Cd、Hg、Cu、Mn和Zn处于偏中度污染,As和Pb属于轻度污染,其余元素处于无污染水平.日均暴露剂量表明,Mn在儿童的非致癌日均暴露剂量最高(摄食:2.83×10-3 mg·(kg·d)-1,呼吸吸入:2.50×10-7 mg·(kg·d)-1,皮肤接触:6.87×10-6 mg·(kg·d)-1),经口摄食是人体暴露的主要途径,Cr的终身暴露剂量最高(儿童:8.63×10-9 mg·(kg·d)-1,成年男性:9.12×10-9 mg·(kg·d)-1,成年女性:8.12×10-9 mg·(kg·d)-1).11种重金属对儿童、成年女性和成年男性的非致癌风险值之和分别为0.58,0.19和0.17,小于可接受风险值1.0,As、Cr、Mn是主要贡献元素;5种致癌元素(Cr、As、Co、Ni和Cd)经呼吸途径对人体的总致癌风险值均小于可接受水平10-6,成年男性(4.29×10-7)略高于儿童(4.06×10-7)和成年女性(3.82×10-7),Cr和As是主要贡献元素.

In order to understand the characteristics and health risk of heavy metals in PM2.5 fraction of road dust in Nanchang city,PM2.5 samples were collected by a resuspension sampler,then concentrations of 11 heavy metals were detected by an inductively coupled plasma mass spectrometer and an atomic fluorescence spectrometer.The results showed that the average concentrations of Mn,Zn,Cr,Cu,Pb,V,As,Ni,Co,Cd and Hg in PM2.5 fraction of road dust were 1014,208.17,106.47,102.40,62.12,39.59,28.93,24.07,7.86,0.58 and 0.53 mg·kg-1,respectively,which were higher than the background values of Nanchang soil except V and Co.The concentrations of heavy metals in secondary roads and branch roads were higher than those of the main road,and were lower than those of other cities.The results of geoaccumulation index revealed that Cd,Hg,Cu,Mn,and Zn were at moderate pollution level,As and Pb showed mild pollution,while the other elements presented no pollution.The average daily exposure dosage showed that Mn in children was the highest(ingestion:2.83×10-3 mg·(kg·d)-1,inhalation:2.50×10-7 mg·(kg·d)-1,dermal contact:6.87×10-6 mg·(kg·d)-1).Ingestion was the major exposure pathway for human health risk.The lifetime exposure dose of Cr was the highest(children:8.63×10-9 mg·(kg·d)-1,adults males:9.12×10-9 mg·(kg·d)-1,adult females:8.12×10-9 mg·(kg·d)-1).The studied heavy metals showed the highest non-carcinogenic risk to children with the non-carcinogenic risk value of 0.58,followed by adult females(0.19)and adult males(0.17),which were all less than the threshold value 1.0,and the major contribution elements were Mn,As and Cr.The five carcinogenic metals Cr,As,Co,Ni and Cd had no carcinogenic risk to human health via inhalable pathway with the risk values of less than the threshold value 10-6.The total carcinogenic risk of heavy metals to adult males(4.29×10-7)was slight higher than that to children(4.06×10-7)and adult females(3.82×10-7),and the major contribution elements were Cr and As.