Abstract
For a better regional and source-risk-based control of heavy metals in urban environments, this study provides a source-specific health risk assessment by combining the models of United States Environmental Protection Agency health risk assessment and positive matrix factorization (PMF). The calculated data were optimized by the geochemical speciation of target 10 potentially toxic heavy metals. The results demonstrated that the mean concentrations of most heavy metals in urban dust of Jinan City exceeded their corresponding background values, especially that of cadmium (Cd) and zinc (Zn) exhibiting a mean of 12.9 and 7.84 times those of their backgrounds. Cd, Zn, copper, lead and manganese in road dust existed mainly in extractable forms, exhibiting higher bio-availability. The PMF receptor model determined four sources of heavy metals in urban road dust, namely industrial discharges (41.1%), natural and coal combustion sources (27.8%), traffic emissions (22.8%), and building material and manufacturing sources (8.3%). All the studied heavy metals presented low or negligible non-carcinogenic risk (non-CR) for adults and children, while the lifetime carcinogenic risk (CR) of Cd was in an acceptable level. Regarding source-specific health risks, the highest non-CR was derived from industrial discharges, while CR from traffic emissions, which were mainly associated with the higher content and bio-availability of Pb and Cd in the dust. Moreover, the risk contributions of industrial discharges and traffic emissions were 35.9% and 60.6% for non-CR and CR, respectively, presenting a significant difference with the apportioned source characteristics, thus deep-revealing the potentially source-based risks of heavy metal in urban environment.
Source-specific health risk assessment of PM2.5-bound heavy metals based on high time-resolved measurement in a Chinese megacity: insights into seasonal and diurnal variations
