珠三角地区大气PM2.5中重金属污染水平及健康风险评价

采集了珠三角地区2014—2015年冬、夏两季的环境空气PM_(2.5)样品,利用电感耦合等离体质谱仪(ICP-MS)测定了样品中的重金属含量,并采用US EPA环境健康风险评价模型,对其健康风险进行了评估.结果表明:环境空气中重金属元素Pb、Cu、Zn、Cd、As、Ni、Cr的浓度分别为11.1~183.0、48.5~406.0、110~1218、0.2~14.4、3.5~77.0、0.38~18.90、2.89~93.20 ng·m-3,浓度大小顺序为:ZnCuPbAsCrNiCd;除As外,其余重金属浓度均表现为冬季高于夏季.元素As经皮肤黏滞及口腔摄入的非致癌风险值均在安全范围内,但经呼吸途径暴露存在非致癌风险;Cu、Zn、Cd、Cr经3种途径暴露不存在非致癌风险;元素Pb、As、Cd、Cr经皮肤黏滞及口腔摄入的致癌风险均值尚在安全值范围内,但经呼吸暴露存在致癌风险;元素Ni经3种途径暴露不存在致癌风险.对于综合危害指数(HI),除As外,其他金属元素的HI值均低于安全值,各金属元素的HI值大小顺序为:AsCdNiCr.研究表明,在珠三角区域环境空气PM_(2.5)中,元素As、Cr存在一定的健康风险.

Concentrations and health risk assessment of heavy metals in atmospheric PM2.5 in the Pearl River Delta Region

Atmospheric PM_2.5 samples in the Pearl River Delta Region were separately collected in the winter of 2014 and the summer of 2015. Concentrations of heavy metals in PM_2.5 were determined by inductively coupled plasma mass spectrometry (ICP-MS). The health risk of heavy metals was evaluated using the US EPA risk assessment model. The results showed that concentrations of Pb, Cu, Zn, Cd, As, Ni and Cr were 11.1~183, 48.5~406.0, 110~1218, 0.2~14.4, 3.5~77.0, 0.38~18.90 and 2.89~93.20 ng·m^-3, respectively. Heavy metal concentrations decreased in the following order:Zn > Cu > Pb > As > Cr > Ni > Cd with higher concentrations in winter than summer except for As. Exposure of As via dermal contact and ingestion were both in the safe range. However, the non-carcinogenic risk values of As exposure via inhalation had potential non-carcinogenic risk. Cu, Zn, Cd and Cr exposure via three ways had no potential non-carcinogenic risk. The carcinogenic risk values of Pb, As, Cd and Cr exposure via dermal contact and ingestion were both lower than the risk threshold. However, the exposure of Cr via inhalation had carcinogenic risk. Ni exposure via three ways had no obvious carcinogenic risk. Except for As, the comprehensive hazard index (HI) values of other heavy metals were all lower than the risk threshold level 1, and the HI order of heavy metals was As > Cd > Ni > Cr. The presence of As and Cr in the atmospheric PM_2.5 in the Pearl River Delta Region may pose risks to human health.