Distribution Characteristics And Health Risk Assessment Of Heavy Metals In Dust Fall In Jiaozuo

As the carrier of harmful substances, the dust fall will cause pollution to the ecological environment. The heavy metals in dust fall can intrude and do harm to the body through the pathway like hand-mouth, breathing and skin and so on. So the heavy metals in dust fall has been paid attention widely. Jiaozuo is a coal-buring city in central China and it has prominent air environmental problems. Studying the distribution characteristics and health risk assessment of heavy metals in dust fall in Jiaozuo has important scientific and realities implications.Dust fall samples were collected in Jiaozuo during the heating period. The heavy metals in the dust fall samples, such as Co, Ni, Cu, Cr, As, Cd and Pb, were measured by inductively coupled plasma mass spectrometry(ICP-MS). The other elements like Ca, Si, Al, Fe, K, Mg and Zn were determined by X-ray fluorescence spectrometry(XRF). The study analysed the distribution characteristics and the sourses of heavy metals in the dust fall, and evaluated the health risk assessment with the model recommended by EPA.The mean value of the dust fall concent in Jiaozuo during the heating period was20.51 t?km-2?month-1, the concent was higher than the average value 14.73 t?km-2?month-1 in the literatures. The concentration ranges of heavy metals like Cr、Co、Ni、Cu、As、Cd、Pb、Zn in the dust fall in Jiaozuo during heating period were 14.18~136.97、3.40~13.98、15.57~63.28、15.05~150.00、19.86~71.49、1.23~22.36、105.52~213.18、487.00~2180.00mg?kg-1, respectively.Referring the elements concentrations of the soil in Henan Province, the result of potential ecological risk index showed that the potential ecological risk index of Cd was far beyond the lower limit of highest limit. The max value of As and Pb achieved the medium level. The geo accumulation index calculations reviewed that the heavy metals in dust fall in Jiaozuo had different levels ecological risks. Cd was particularly serious.Secondly was Zn and Pb.The enrichment factor and the factor analysis results showed that there were four mainly sources of the dust fall in Jiaozuo during the heating period: the soil dust, the industry dust, fuel and coal buring dust and road dust. The proportions were 24.89%、19.33%、16.89%、9.51%, respectively. The heavy metals in dust fall were mostly from human pollution.The child non carcinogenic hazard quotient was 1.49. and the adult was lower than 1. The results showed the heavy metals in dust fall in Jiaozuo during heating period had non-carcinogen risk to the child. The child non carcinogenic hazard quotient of Pb and Cr were close to 1. The phenomenon shoule be paid more attention. The carcinogen risk ranged from 5.80×10-10 to 1.48×10-7. The data were lower than the threshold value of carcinogenic risk both child and adult. It had no threat to the residents yet.