郑州市采暖期与非采暖期PM_(2.5)中重金属来源及潜在健康风险评价

Source apportionment and health risk assessment of heavy metals of PM_(2.5) in heating and non-heating period in Zhengzhou

为了研究郑州市PM2.5中部分金属元素在采暖期与非采暖期的来源、污染特征并进行相应的生态风险及健康风险评价,于2016年春季非采暖期和冬季采暖期在河南郑州设置采样点,采集有效膜样本105个.测定PM2.5质量浓度及其中Zn、Pb、Cu、As、Cd、Co、Mn、Fe共8种金属元素含量,郑州2016年非采暖期PM2.5质量浓度日均值为113.41μg·m^-3、采暖期为216.99μg·m^-3,采暖期中Cu、Zn、As、Cd这4种元素的浓度分别是非采暖期的2.3、2.0、1.9、1.5倍,季节性差异明显.富集因子分析显示郑州地区Cd元素富集程度最高已超过1000,受人为影响严重.PMF源解析表明燃煤源及机动车源是郑州采暖期重金属主要来源,贡献率为48.00%和34.95%;扬尘源及交通污染源在非采暖期的贡献率为55.92%和31.08%.健康风险评价显示3种致癌元素As、Cd、Co的致癌风险值均小于10-4,Mn的非致癌风险值最高为0.9,可能存在一定的非致癌风险.

A total of 105 PM2.5 samples were collected from an urban site in Zhengzhou during spring and winter of 2016 to illustrate the heating effect on pollution characteristics and source contributions,subsequently assessment of ecological risk and health risk of the toxic elements.The mass concentration of PM2.5 and 8 metals(Zn、Pb、Cu、As、Cd、Co、Mn、Fe)were determined.The results showed that the daily mean concentrations of PM2.5 were substantial different with value of 113.41μg·m^-3 and 216.99μg·m^-3 in non?heating period and heating period,respectively.The values of Pb、Cd、Cu、Zn、As and Mn in heating period were 2.7、2.3、1.9、2.0、1.3 and 1.6 times compare to those in non?heating period.The Cd element in PM2.5 enriched significantly with EF more than 1000,which related to intensity human activities.The result of PMF showed that coal burning and traffic were the main sources of heavy metals in PM2.5 during heating period,which account to 48.00%and 34.95%,respectively.The contributions of dust and traffic in non?heating period was 42.07%and 28.48%,respectively.The health risk assessment showed that the carcinogenic risk values of the three carcinogenic elements As,Cd and Co were all less than 10-4,the highest non?carcinogenic risk value of Mn is 0.9,which may have some non?carcinogenic risk.