Phthalate esters in biota, air and water in an agricultural area of western China, with emphasis on bioaccumulation and human exposure

Phthalate esters (PAEs) have been shown to be ubiquitous in abiotic and biotic environmental compartments; however, information about bioaccumulation behavior and human exposure, both via environmental exposure and the diet, are limited. Herein, we report the concentrations and composition profiles of phthalate esters (PAEs) in biological samples, river water, indoor air, and outdoor air samples collected from an agricultural site in western China. Dibutyl phthalate (DNBP) occupied a relatively high abundance in biological samples, discrepant with the environmental samples in which di-(2-ethylhexyl) phthalate (DEHP) was the dominant congener. Significant correlations (P < 0.05) were observed between the biota and river water samples, indicating that river water heavily influenced PAE accumulation in biological samples. The mean log Bioaccumulation Factors (BAFs) varied from 0.91 to 2.96, which implies that most PAE congeners are not likely to accumulate in organisms. No obvious trends were observed between log octanol-water partition coefficient (KOW) and log BAF values, nor between log octanol-air partition coefficient (KOW) and biota-air accumulation factors (BAAFs). Nevertheless, the calculated log air-water partitioning factors (AWPFs) of diethyl phthalate (DEP), dimethyl phthalate (DMP), and butyl benzyl phthalate (BBP) were similar to predicted values whereas those for diisobutyl phthalate (DIBP), DNBP and DEHP were significantly higher. The estimated daily intakes of PAEs via food ingestion and environmental exposure were 15, 9.4 and 1.2 ng/kg-bw/day in toddlers, children and adults, respectively, laying at the low end of the reported data and well below the reference dose.