Polycyclic aromatic hydrocarbons and phthalic acid esters in vegetables from nine farms of the Pearl River Delta, South China

Abstract

This study investigated the occurrence of 16 polycyclic aromatic hydrocarbons (PAHs) and 6 phthalic acid esters (PAEs) in 11 vegetable species collected from nine farms of the Pearl River Delta, South China. Twelve PAH compounds and all PAE compounds were detected by gas chromatography coupled with mass spectrometry (GC-MS) in vegetables. The total concentrations of PAHs (Sigma(PAHs)) and PAEs (Sigma(PAEs)) ranged from 7.0 to 5353 microg kg(-1) dry weight (d.w.), with a mean value of 1173 microg kg(-1) d.w., and from 0.073 to 11.2 mg kg(-1) d.w., with a mean value of 3.2 mg kg(-1) (d.w.), respectively. The highest levels of Sigma(PAHs) and Sigma(PAEs) were found in Brassica juncea and Brassica parachinensis, respectively. For the same vegetable, the bioconcentration factors (BCFs; the ratio of contaminant concentration in plant tissue to the soil concentration) of PAHs (between 0.0037 and 5.5) are generally higher than those of PAEs (between <0.0001 and 0.61). It was also noted that there were great variations of organic contaminant levels, BCFs, and benzo[a]pyrene equivalent concentrations, which depend on the various contaminants, sampling locations, and vegetable species. The occurrences of PAHs and PAEs in this study are compared with those in other studies and their sources are discussed.