Occurrence, Distribution and Health Risk of the Phthalate Esters in Riparian Soil in the Fluctuating Zone of the Three Gorges Reservoir

Abstract

Soil samples were collected in the fluctuating zone of the Three Gorges Reservoir to analyze the concentrations and distribution of phthalate esters (PAEs) using ultra performance liquid chromatography-quadrupole-time of flight mass spectrometry (UPLC-Q-TOF-MS). Meanwhile, the interrelationships among the PAE congeners were analyzed and the potential sources of PAEs in soil were determined by the correlation analysis and principal component analysis. The results showed that the concentrations of ∑PAEs ranged from 322.0-737.3 ng·g-1 dry weight, with a mean value of 497.2 ng·g-1 dry weight, which lies at the low end of the worldwide Figures. DIBP was the most abundant PAEs congener, followed by DBP and DEHP, contributing to 94.5% of the total PAEs. However, DEHP was not the main pollutant in this study compared to other studies, which might be ascribed to the release of DEHP from the flooded soil to the surrounding water but the degradation by microorganisms in the soil cannot be completely ruled out. Significant interrelationships were observed among DMP, DEP, DBP, and DIBP. The principal component analysis showed that DMP, DEP, DBP, and DIBP may have similar sources. In this study, the daily intake dose was lower than the reference dose (RfD) proposed by the United States Environmental Protection Agency (USEPA), and the carcinogenic risk of six PAE congeners was far below the tolerable values proposed by the USEPA. Nevertheless, the daily intake dose of DBP accounted for 60% to 84% of total PAEs; thus, more attention should be paid to the potential health risks of DBP.