Ecological Risk and Health Risk Assessment of Dioxin-like PCBs in Liaohe Estuarine Wetland Soils, China

Abstract

Forty one soil samples were collected from Liaohe estuarine wetland in May 2009 for assessing the distribution, ecological risk, and health risk of dioxin-like PCBs (dl-PCBs). The total concentrations of 12 dl-PCBs ranged from 0.36–1.36 ng/g, with a mean value of 0.77 ng/g. The dominant dl-PCBs were Tetra-CBs, which contributed to 43.9% of the total. The ecological risk of dl-PCBs was analyzed based on the toxic equivalent (TEQ) approach. In this study, the TEQ concentrations of dl-PCBs in soils varied from 0.06–22.55 pg/g, with a mean value of 8.18 pg/g. Human health risk was evaluated based on the non carcinogenic and carcinogenic risk method. Non carcinogenic risk was measured using a hazard quotient (HQ) values for 95% upper control limit (UCL) and maximum concentrations of dl-PCBs. HQ values were lower than 1 under both exposure scenarios, which indicated that the non carcinogenic risk of dl-PCBs was negligible. Carcinogenic risk was estimated based on the criteria of ingestion, dermal contact and inhalation of soils. Carcinogenic risk values were less than 10⁻⁶, which exhibited negligible cancer risk for infant, child and adult, respectively, through ingestion, dermal contact, and inhalation pathway.

Key Words:

• carcinogenic risk
• dl-PCBs
• ecological risk
• non-carcinogenic risk
• wetland soils