Pollution Characteristics and Health Risk Analysis of Heavy Metals in PM₁₀ and PM_2.5 in Typical Cities in Hunan Province

To investigate the pollution characteristics and health risks of heavy metals in particulate matter in Changsha, Zhuzhou, Xiangtan (CTZ) area in Hunan Province, PM₁₀ and PM_2.5 filter samples were collected in Changsha, Xiangtan and background site of Hengshan Mountain in August 2014. The concentrations of ten heavy metals were analyzed by inductively coupled plasma mass spectrometry. In order to assess the carcinogenic risk of Cr(Ⅵ) on human, Cr(Ⅵ) concentrations were calculated based on the reference ratio of 0.13 for Cr(Ⅵ) to total Cr. The health risk of heavy metals inhaled by respiratory system was assessed by the model recommended by US EPA, coupled by the exposure factors in China. Results showed that the mass concentration of PM₁₀ and PM_2.5 were respectively 42-155 μg/m³ and 18-119 μg/m³ in Changsha, and were 17-127 and 5-109 μg/m³ in Xiangtan. The concentration of Cr(Ⅵ) in Changsha and Xiangtan was 0.81 and 0.65 ng/m³ in PM₁₀ samples, while that of As was 9.3 and 6.3 ng/m³, much higher than the relevant Chinese air quality standards. The total non-carcinogenic risk of the each heavy metal was less than 1, within the acceptable level. The carcinogenic risks for Cr(Ⅵ) and As were in the range of 10^-6-10^-4, belonging to the range of potential carcinogenic risks. The carcinogenic risks for Cd, Ni and Co were below 10^-6, indicating that the carcinogenic risks of the three metals are acceptable.