南京市大气PM_(2.5)中金属污染特征及慢性健康风险评价

Pollution characteristics and chronic health risk of heavy metals in atmospheric environment PM_(2.5) in Nanjing city

目的了解南京市大气PM_(2.5)及其中金属成分的污染特征,分析金属来源并开展健康风险评价,为采取针对性的控制措施和做好人群防护提供依据。方法于2021年每月10—16日开展PM_(2.5)采样,分别采用称重法和电感耦合离子质谱法测定PM_(2.5)质量浓度及金属含量,利用富集因子法分析金属成分的污染来源,利用慢性健康风险评价模型评价金属成分的呼吸暴露风险。结果2021年南京市江北新区和江宁区两个监测点的PM_(2.5)年均浓度中位数分别为39μg/m^(3)、36μg/m^(3),江北新区PM_(2.5)年均浓度高于江宁区,差异有统计学意义(Z=-1.983,P=0.047),两个监测点不同季度的PM_(2.5)浓度差异有统计学意义(P<0.01),最高浓度均在第一季度,最低浓度均在第三季度。两个监测点PM_(2.5)中Cd、Se、Tl这3种金属成分的质量浓度均为江北新区高于江宁区,差异有统计学意义(P<0.05)。两个监测点PM_(2.5)中金属成分的富集因子值均超过10,提示污染主要来源于人为活动。两个监测点金属成分的非致癌风险值均小于1,可认为不会对人体造成明显的非致癌健康风险。江北新区As、Cd、Cr和江宁区As、Cr的终生超额致癌风险介于10^(-6)~10^(-4)的可接受风险水平之间,表明这些金属成分对人群具有潜在致癌风险。Cr的致癌风险最大,其次是As。结论本次调查的两个监测点大气PM_(2.5)中金属成分多源于人为污染,其非致癌风险较低,部分金属成分存在潜在的致癌风险。

Objective To understand the pollution characteristic of PM_(2.5)and the heavy metals in PM_(2.5)in Nanjing,and analyzes the source and assesses the health risk of heavy metals.Methods The PM_(2.5)samples collected from 10th to 16th of each month in 2021.The contents of PM_(2.5)and heavy metals were determined by weighing method and inductively coupled plasma mass spectrometry,and source apportionment was determined by using enrichment factor and chronic health risks of heavy metals were assessed.Results The median of the average annual PM_(2.5)concentrations of the Jiangbei new district and Jiangning district were 39 and 36μg/m^(3)respectively,with significant difference(P<0.047).The PM_(2.5)concentrations of the Jiangbei new district were higher than those in Jiangning district.The seasonal differences of PM_(2.5)were statistically significant(P<0.01),and the concentrations of PM_(2.5)was highest in the first quarter and was lowest in the third quarter.The difference of the concentration of Cd,Se,Tl was statistically significant in the different seasons(P<0.05).The EF of the heavy metals in two monitor sites were greater than 10,and that the element was mainly affected by human activities.The non-carcinogenic risks of the heavy metals in two monitor sites were less than 1,and they were lower than the safe level for children and adults.The carcinogenic risks from As,Cd,Cr in Jiangbei new district and As,Cr in Jiangning district were in the acceptable level(10^(-6)-10^(-4))for children and adults,and they posed a carcinogenic risk to all people.Cr had a highest carcinogenic risk and followed as As.Conclusion The heavy metals in PM_(2.5)mainly come from anthropogenic pollution.The non-carcinogenic risk of inhalation of heavy metals is low,and the potential carcinogenic risk of some heavy metals is under average acceptable level in Nanjing.