Ambient Air Heavy Metals in PM2.5 and Potential Human Health Risk Assessment in an Informal E-waste Recycling Site of China

摘要

Worldwide, electronic waste (e-waste) has become one of the most rapidly growing sources of human residues. Guiyu is one of the largest e-waste destinations and recycling areas in the world. Particulate matter with an aerodynamic diameter less than 2.5um (PM2.5) in the atmosphere is a significant concern for human health. The informal structure of processing and recycling e-waste in Guiyu has led to the release of several carcinogenic and hazardous substances into the air, which may lead to adverse health effects for humans. To estimate the health effects of particulate matter for local residents, we assessed the potential public health risk associated with the heavy metal composition of PM2.5. Daily samples of PM2.5 were collected with Harvard Impactors on the roof of 3-story buildings from March 2012 - April 2013 in Guiyu (n=133) and a reference site, Haojiang (n=33). The mass concentrations of PM2.5 were determined by gravimetric analysis. Filters were digested by microwave and used to determine Pb, Cd, Cr, and Mn by GFAAS. The geometric mean of concentrations of PM2.5, Pb and Cd in Guiyu were higher than in the reference area (PM2.5:49.91 μg/m3 vs. 37.60 μg/m3, p＜0.01; Pb: 164.03 ng/m3 vs. 69.26 ng/m3, p＜0.001; Cd: 5.69 ng/m3 vs. 3.39 ng/m3, p＜0.01), but Cr and Mn concentrations were not (Cr: 4.51 ng/m3 vs. 3.81 ng/m3, p＞0.05; Mn: 16.93 ng/m3 vs. 15.64 ng/m3, p＞0.05). The metal concentrations in PM2.5 from Guiyu were also higher when compared to other Asian cities. We observed higher heavy metal concentrations during winter and spring seasons. Human health risk assessments have shown that the carcinogenic and non-carcinogenic elements in PM2.5 might pose more serious public health risk to children than adults. In summary, exposure to ambient air PM2.5 and metals (Pb, Cd) were higher in Guiyu compared with the reference site. Air pollution resulting from informal e-waste recycling activities might be affecting the health of local residents, especially children.