石家庄市大气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 PM2.5 in Shijiazhuang

目的了解石家庄市大气PM2.5及其中重金属的污染特征,对其健康风险进行评估。方法2015年1月至12月在石家庄市某城区采集大气PM2.5样品102个,分析As、Cd、Cr、Ni、Pb、Hg和Mn 7种重金属元素含量和污染特征,采用美国环保署推荐的健康风险评价模型进行健康风险评价。结果石家庄大气PM2.5的24 h平均浓度范围为20~710μg/m3,均值为(190±140)μg/m3;中位数为150μg/m3,约超过《环境空气质量标准》(GB 3095—2012)的二级标准限值(75μg/m3)1.0倍。PM2.5中7种重金属元素的浓度范围为0.01~305 ng/m3,仅As 24 h平均浓度的中位数(13.6 ng/m3)超标1.3倍;除Hg外,其他金属平均浓度均表现为冬季高于夏季。石家庄市大气PM2.5中非致癌物Pb、Hg、Mn经呼吸途径的年均超额危险度为1.95×10-12~7.22×10-10,致癌物As、Cd、Cr、Ni的年均超额危险度为1.99×10-9~4.01×10-7。致癌物中Cd和Cr的冬季人群超额危险度分别在5.92×10-8~8.85×10-8、6.15×10-7~8.66×10-7之间,均高于夏季;非致癌物质中Mn和Pb的冬季人群超额危险度高于夏季。结论2015年石家庄市大气PM2.5污染较重且具有明显的季节性特点,4种致癌重金属的年致癌风险均低于10-6,尚未对人群造成致癌风险,应进一步关注PM2.5中Cr对人体的致癌风险。

Objective To understand the pollution characteristics of heavy metals in PM2.5 in Shijiazhuang and to assess the health risks.Methods A total of 102 ambient PM2.5 samples were collected from January 2015 to December 2015 in an urban area of Shijiazhuang for determination of PM2.5 and seven heavy metals,as well as health risk assessment by the recommended USEPA model.Results The concentration of PM2.5 was(190±140)μg/m3(20-710μg/m3),the median(150μg/m3)exceeded1.0 time of the two-grade limit(75μg/m3)ruled by Ambient Air Quality Standards(GB 3095-2012).The levels of heavy metals in PM2.5(0.01-305 ng/m3)were qualified,except that As(13.6 ng/m3)exceeded 1.3 time of limit.The heavy metals in PM2.5 revealed higher levels in winter than those in summer except Hg.The annual average risks were 1.95×10-12-7.22×10-10 for Pb,Hg and Mn,among which the risks of Pb and Mn were higher in winter,and 1.99×10-9-4.01×10-7 for As、Cd、Cr and Ni,among which the risks of Cd(5.92×10-8-8.85×10-8)and Cr(6.15×10-7-8.66×10-7)were higher in winter also.Conclusion The metals pollution in PM2.5 is serious and has obvious seasonality in Shijiazhuang in 2015,and the risks of four heavy metals(<10-6)is acceptable,but Cr need to be paid more attention to.