Occurrence of Organophosphate Esters in Soils of the Three Gorges Reservoir

Abstract

Organophosphate esters (OPEs) were first identified and quantified in farmland and riparian soil in the Three Gorges Reservoir (TGR) of western China. The mean concentrations of OPEs were 272 ng·g-1 dry weight (dw) in farmland soil and 498 ng·g-1 dw in riparian soil. These values lie at the middle of the range of worldwide values. Hydrodynamic conditions might be important factors contributing to the slightly different spatial distribution of the OPEs. The concentrations of the OPEs in riparian soil exceed those in farmland soil, which could partly be ascribed to the operation of the Three Gorges Dam (TGD). Of particular note is the elevated contribution of TCP, followed by EHDPP, accounting for more than 90% of the total OPEs, and the degradation of TBEP by microorganisms in the soil could be related to the low occurrence of TBEP. Significant correlation between the OPE concentrations in farmland and riparian soil were obtained, indicating that the OPEs in farmland and riparian soil originated from the same source. A principal component analysis (PCA) showed that the OPEs in farmland soil might come largely from construction and decoration materials, and the OPEs in riparian soil may be derived from a combination of construction materials and vehicular traffic emissions.