Levels and risk assessment of selected persistent organic compounds in dust samples from Tianjin, China

Abstract

The aim of this paper was to determine spatial variation of 6 indicator polychlorinated biphenyls (PCBs) and 18 organochlorine pesticides (OCPs) in street dust samples (n=49) collected during summer season from suburban/urban zones of Tianjin, China. Sample preparation was performed by using accelerated solvent extraction with simultaneous extraction and clean-up of PCBs and OCPs, while quantification was carried out using gas chromatography coupled with microelectro absorption detector and gas chromatography coupled with mass spectrometry. The total concentrations of studied PCBs varied from <method limit of quantification (MLOQ) (0.028) to 6.38 ng/g (mean 0.72 ng/g and the median value of 0.028 ng/g), while the total concentrations of studied OCPs varied from <MLOQ (0.020) to 123 ng/g (mean 33.6 ng/g and the median value of 25.9 ng/g). Regarding the OCPs analyzed, dichlorodiphenyltrichloroethanes (DDTs), beta-hexachlorocyclohexane (β-HCH), and γ-HCH were quantified, while all indicator PCBs were quantified at least in one sample, with the exception of PCB 180. Additional, principal component analysis was performed to evaluate relationships between quantified compounds (PCBs, DDTs, and HCHs) and dust characteristics. No correlation was found among quantified compounds and dust characteristics with the exception of PCB 101 and PCB 138, which correlates positively with pH and negatively with conductivity. The total lifetime carcinogenic risk (TLCR) as well as total non-carcinogenic risk hazard quotient (TnHQ) indicated that the risk to the human population related to the presence of OCPs and PCBs in dust samples was acceptable.