Levels, Sources, Markers and Health Risks of Heavy Metals in PM2.5 Over a Typical Mining and Metallurgical City of Central China

Abstract

To investigate the pollution characteristics, sources and health risk assessment of various elements in PM2.5 of Huangshi city, 54 samples were collected from March 2012 to February 2013. The composition and characteristic of sixteen elements (Mg, Al, Ca, Ti, Cr, Mn, Cu, Zn, V, Fe, As, Pb, Cd, Co, Ni and W) were analyzed by high-sensitivity X-ray fluorescence (XRF). The result showed that the annual mean concentration of PM2.5 was 104.4 μg/m3, far exceeding the secondary level of Ambient Air Quality Standard of China (annual average limit 35 μg/m3). Element W has the highest annual concentration, followed by Zn, Pb and As. Compared with the concentration limit of National Ambient Air Quality Standard of China, Cd and As in Huangshi were 4.3 times and 32.8 times higher, respectively, than national standard. The concentration of most elements has distinct seasonal characteristic which is higher in winter and lower in summer. Enrichment factor (EF) analysis indicates that W, Fe, Cd, As, Pb, Zn, Cu, Cr, Co and Ni are extremely enriched in PM2.5, Ca, Mg and Mn are highly enriched, and V is significant enriched. EF of Ti is less than 2, suggesting minimal pollution. Positive matrix factorization (PMF) analysis indicates that Ca, Ti and Al are associated with fugitive dust, and As is associated with coal-fired industrial activity. W, Cr, Cd, V and Ni are originated from chemical and metallurgical industry activities. Pb, Zn, Cu and Mg are derived from vehicle emissions. The results of the human health risk assessment model show that As may pose great non-carcinogenic risk to children and adults. Cr and As have a higher carcinogenic risk for adults, and Cr has a higher carcinogenic risk for children, and other toxic metals are in relatively safe range.