宁波市某城区大气PM2.5中重金属污染特征及健康风险评价

目的调查宁波市某城区大气PM2.5中重金属污染水平,评估对人体潜在健康风险。方法2016年每月10~17日在宁波市某区儿童医院4层楼顶平台采集大气中PM2.5颗粒物,采用电感耦合等离子体质谱法测定PM2.5中12种重金属水平,采用美国环境保护署(EPA)经典"四步法"对重金属吸入途径进行人群健康风险评估。结果PM2.5平均浓度0.046(0.010~0.160)mg/m^3,PM2.5中12种重金属平均总浓度176.44 ng/m^3(35.48 ng/m^3~436.71 ng/m^3),呈冬春季高,夏秋季低。人群吸入PM2.5中重金属致癌风险和非致癌风险呈随季节性变化,总体呈冬季>春季>秋季>夏季。其中砷(As)和镉(Cd)致癌风险分别为6.86×10^-6和1.06×10^-6,12种金属对人群全年和不同季节平均非致癌健康风险值均<1。结论宁波市城区大气存在PM2.5污染,应重视As和Cd健康风险。

Pollution and health risk assessment of heavy metals in PM2.5 in a district of Ningbo

Objective To describe the pollution of heavy metals in PM2.5 in Ningbo,and to evaluate the potential health risks to human beings by inhalation.Methods The air samples containing PM2.5 were collected monthly in a district of Ningbo in 2016,and 12 types of heavy metals in PM2.5 were determined by inductively coupled plasma mass spectrometry(ICP-MS).The potential health risk of the heavy metals to human bodies by inhalation was assessed using EPA"four-step"method.Results The average concentration of PM2.5 was 0.046(0.010-0.160)mg/m^3.The average concentration of 12 heavy metals was 176.44(35.48-436.71)ng/m^3,which was higher in autumn and winter and lower in spring and summer.The carcinogenic risk and non-carcinogenic risk of heavy metals in PM2.5 varied which was the highest in winter and lowest in summer.The carcinogenic risks of As and Cd were 6.86×10^-6 and 1.06×10^-6.The average non-carcinogenic health risk value of 12 metals was less than 1 in every season during the entire year.Conclusions The PM2.5 pollution in Ningbo is serious.Attention should be paid to the health risks of As and Cd is PM2.5.