Occurrence of heavy elements in street dust from sub/urban zone of Tianjin: pollution characteristics and health risk assessment

Abstract

Main purpose of this study was to determine the concentrations of selected heavy elements (As, Cd, Pb, Cu, Co, Cr and Ni) in the street dust samples (n = 49) collected from seven districts located in suburban/urban zone of Tianjin in order to estimate their possible sources and degree of environmental pollution as well as human health risk. Mean concentrations (mg kg−1) of As (19.3), Cd (0.60), Pb (28.4) and Cu (62.7) were above their corresponding soil background values. According to the results of multivariate statistical analysis, the accumulation of As, Cd, Pb, Cu and Cr in street dust was affected by anthropogenic activities, while the contents of Ni and Co were associated with natural sources. Pollution degree by geo-accumulation index had the following trend: Cd > Cu > As > Pb > Cr > Ni > Co. Dust contamination with Cd ranged from unpolluted to highly polluted. Potential ecological risk indicated low (Pb, Cu, Cr, Co and Ni) to high (Cd) risk, while potential risk index showed moderate and very high risks. Non-carcinogenic risk of the studied elements was below safe level (<1). Data obtained in this investigation gave the additional values to the knowledge needed for future monitoring and risk assessment, relating the presence of heavy elements studied in suburban/urban areas.