Application of P450RGS reporter gene system as a bioindicator of sediment PAH contamination in the vicinity of Incheon Harbor, Korea

Abstract

Sixty seven sediment samples were collected from Kyeonggi Bay, Korea, including the mouth of Han River, Incheon Harbor, the Namdong industrial complex, and the open sea. Collections were conducted in December, 1995 and samples were maintained frozen (-20 °C) until analysis. Dichloromethane extracts were analysed for their content of CYP1A1-inducing compounds with a P450RGS (reporter gene system) assay, and for polycyclic aromatic hydrocarbons (PAHs). Sediment samples were also analysed for organic carbon (OC) content and grain size, to aid in evaluating the relationship between contamination and physical nature of the sediments. The responses of the P450RGS assay to the sediment extracts were expressed as μg of benzo[a]pyrene toxic equivalents per g dry weight (μg g^-1 BaPTEQ), and these values correlated well (r² = 0.624 with total PAHs. BaPTEQ values were also highly correlated with the OC content of the sediments. The determination of P450RGS BaPTEQ is a useful tool, because it is both a rapid and inexpensive means of assessing the potential toxicity of organic compounds in environmental sediment samples. These values represent an estimate of the levels of compounds in the sediment that are potentially available to organisms through chronic exposure to pore water or ingestion of benthic species. We believe BaPTEQ values are more useful than tables of specific PAH concentrations, if the purpose of the investigation is to either obtain a rapid screening of an area or to develop some form of ecological or human health risk assessment.

Keywords::

• Cyp1a1, P450rgs Bapteq, Pah, Bioindicator, Screening Method