Distribution of phthalate esters in urban soils of subtropical city, Guangzhou, China

Surface soils from 37 sampling sites including roadsides (RS), parks (PA) and residential areas (RE) of the Subtropical City, Guangzhou, were collected in December of 2005 and analyzed for 16 phthalate esters (PAEs). PAEs were detected in all surface soils analyzed, which indicate that PAEs are ubiquitous environmental contaminants. The summation operator(16)PAEs concentrations ranged from 1.67 to 322 microg g(-1)-dry weight (dw), with the median concentration of 17.7 microg g(-1)-dw, mainly originating from municipal solid waste leachate, discarded plastic effusion, municipal sewage and atmospheric depositions. Concentrations of PAEs were poorly correlated with soil organic carbon content, suggesting mixing process between local and on-going sources. Of the 16 PAEs, diisobutyl phthalate (DiBP), di-n-butyl phthalate (DnBP) and di(2-ethylhexyl) phthalate (DEHP) dominated the PAEs, with the median concentrations of 1.63 microg g(-1)-dw, 1.80 microg g(-1)-dw and 14.8 microg g(-1)-dw, respectively, and accounted for 74.2-99.8% of the summation operator(16)PAEs concentrations. Principal Component Analysis (PCA) was applied to the distribution patterns of PAEs in the urban soils. Significant correlations existed among DiBP, DnBP, and DEHP, and between dimethyl phthalate (DMP) and diethyl phthalate (DEP). No significant differences of PAE congeneric profiles were observed between this and studies conducted elsewhere, which is consistent with the application of similar commercial PAEs around the world. As compared to the results from other studies, the urban soils of Guangzhou city were severely contaminated with PAEs. The environmental and human health risks posed by PAEs in the urban soils of Guangzhou city may deserve further attention.