深圳大气PM2.5中重金属污染特征及健康风险评价

Pollution characteristics and health risk assessment of heavy metals in ambient PM2.5 in Shenzhen

目的了解深圳市大气PM2.5中重金属污染特征及对人体的健康风险。方法于2017年在深圳市龙岗区、南山区和盐田区采集PM2.5样品,分析其中砷(As)、镉(Cd)、铬(Cr)、镍(Ni)、铅(Pb)、锌(Zn)、汞(Hg)、铜(Cu)和锰(Mn)等9种重金属元素的含量和污染特征,并采用美国环境保护署健康风险评价模型对重金属进行呼吸暴露健康风险评价。结果深圳三个区大气PM2.5中9种重金属元素的浓度范围为1.50×10-9~9.03×10^-4mg/m^3,其中盐田区Zn的平均浓度(2.20×10^-4mg/m^3)最高,Hg的平均浓度(1.14×10^-8mg/m^3)最低。三个区PM2.5中砷、镉、铅、汞的平均浓度均低于GB3095-2012《环境空气质量标准》二级标准限值,其中As的浓度接近国标。三个区PM2.5中Cd、Cu、Zn的富集因子(enrichment factor,EF)>10,Pb、As、Hg、Ni的EF在1与10之间,Cr的EF<1。9种重金属通过呼吸途径对暴露人群的年均超额危险度在3.06×10^-13~2.03×10^-7之间,均低于人群可接受的危险度水平(10^-6),其中以As和Cr的潜在危害最大。结论深圳市三个区PM2.5中9种重金属平均浓度均低于GB3095-2012中的限值,健康风险低于最大可接受风险值。

Objective To investigate the pollution characteristics and health risk assessment of heavy metals in ambient PM2.5 in Shenzhen City.Methods PM2.5 samples were collected in Longgang District, Nanshan District and Yantian District of Shenzhen City in 2017, and then the concentration and pollution characteristics of 9 heavy metals (including As, Cd, Cr, Ni, Pb, Zn, Hg, Cu and Mn) were analyzed. The inhalation exposure and risk assessment of these heavy metals was carried out by using US EPA Health Risk Assessment Model.Results The concentration of the 9 heavy metals in ambient PM2.5 was 1.50×10^-9-9.03×10^-4 mg/m^3 in the 3 districts of Shenzhen, of which the average concentration of Zn in Yantian District was the highest (2.20×10^-4 mg/m^3), and the average concentration of Hg was the lowest (1.14×10^-8 mg/m^3). The average concentration of As, Cd, Pb and Hg was lower than the limit for grade two ruled by the Ambient Air Quality Standard (GB 3095-2012), of which the average concentration of As was close to the limit. The enrichment factors of Cd, Cu and Zn in ambient PM2.5 in the 3 districts were greater than 10, those of Pb, As, Hg and Ni were between 1 and 10, and thatof Cr was less than 1.The annual average excess hazard indexes of the 9 heavy metals via inhalation exposure were3.06×10^-13 - 2.03×10^-7, which were below the risk threshold level of population (10-6), with the greatest potential hazard of As and Cr.Conclusions The average concentration of the 9 heavy metals in ambient PM2.5 in the 3 districts of Shenzhen is lower than the limit in GB 3095-2012, and the health risks are below the maximum acceptable risk values.