Source-specific risks apportionment and critical sources identification of potentially harmful elements in urban road dust combining positive matrix factorization model with multiple attribute decision making method

Abstract

The present study aimed to explore the source-specific ecological and human health risks, and to identify critical sources of potentially harmful elements (PHEs) in road dust. Forty road dust samples were collected from Taiyuan, which is a typical industrial city in China, and analyzed for the concentrations of As, Cd, Pb, Ni, Cr, Cu, and Zn. Positive matrix factorization model and multiple attribute decision making method (MADM) were applied to assess source-specific risks and identify the critical sources of dust PHEs. There were high concentrations of PHEs in the dust, especially for Cd, Pb, Cu, and Zn, which had concentrations more than twice the corresponding background concentrations in Taiyuan soil. The ecological risks demonstrated that PHEs in dust posed moderate risks at 72.89% of the sampling locations, and considerable risks at approximately 10% of the sampling locations. Human health risk assessment indicated that the non-carcinogenic and carcinogenic risks of dust PHEs to humans were within safe levels. However, As and Cr, which are two primary elements in dust that are hazardous to human health, were of concern. The three main sources of dust PHEs were natural sources, traffic exhaust, and industrial emissions, which accounted for 26.06%, 52.30%, and 21.62% of the total PHEs concentration, respectively. The result of source-specific ecological and human health risk analyses indicated that the contributions of certain sources to various factors varied widely, which was attributed to the different factors being most strongly related to different elements. Industrial emission contributed least to the total dust PHEs among three sources, however, the Zp values of industrial emission (0.37), which was calculated by MADM, was higher than of natural source (0.31) and traffic exhaust (0.33), industrial emission was therefore identified as the critical source for dust PHEs. Our results demonstrate that critical source identification should be considered when managing pollutant sources to decrease the perniciousness of contaminants.