Current State, Distribution, and Sources of Phthalate Esters and Organophosphate Esters in Soils of the Three Gorges Reservoir Region, China.

ABSTRACT

Phthalate esters (PAEs) and organophosphate esters (OPEs) were identified and quantified in surface soils from farmland and riparian areas of the Three Gorges Reservoir (TGR), western China. Generally, the mean values of PAEs and OPEs were 618 and 266 ng/g dry weight (dw) in farmland soil and 560 and 499 ng/g dw in riparian soil, respectively. The occurrence of OPEs should be regarded as a risk factor in the TGR region. Analogous spatial distribution patterns for PAEs were observed with higher concentrations observed at site WZ in both types of soil, which might relate to the anthropogenic activities. The hydrodynamic conditions might be important factors contributing to the slightly different spatial distribution of OPEs. The concentrations of OPEs in riparian soil exceed those in farmland soil at all sampling sites, which could partly be ascribed to the complete operation of the TGR. Dibutyl phthalate (DnBP) was the most dominated PAEs congener in both types of soil. Of particular note is the elevated contribution of tris(methylphenyl) phosphate (TMPP), followed by 2-ethylhexyl diphenyl phosphate (EHDPP), accounting for more than 90% of the total OPEs, and the shipping or/and the local human activity might be considered as the major contributor. The slight differences in PAEs composition of principal components might largely attribute to the variety of emission sources in two types of soil. The different cluster patterns between two types of soil indicated that the anthropogenic activities as well as the full operation of TGR, may play a role.