Application of P450 reporter gene system (RGS) in the analysis of sediments near pulp and paper mills

Abstract

Cytochrome P4501A (CYP1A) induction in fish and other animals has been reported following exposure to pulp and paper mill effluent. Dioxins and furans as well as polycyclic aromatic hydrocarbons (PAH) are known inducers of CYP1A and have been found in sediments near pulp and paper mills. Retene (7-isopropyl-1-methylphenanthrene), an alkyl-substituted phenanthrene, has been recently associated with effluent and found to induce CYP1A in fish. This study utilized an in vitro assay, P450 Reporter Gene System (RGS), to assess the transcriptional activation of human CYP1A by retene after short (6 h) and long (16 h) exposures. Retene was as potent as benzo[a]pyrene in inducing RGS, but was not as readily biotransformed by the cells. Extracts of sediments collected near a pulp and paper mill were analysed, and RGS-derived toxic equivalencies (TEQ) were strongly correlated with Chemical TEQ analysis of dioxins and furans determined by EPA Method 8290 using high-resolution gas chromatography/mass spectrometry. RGS 6-h responses indicated the presence of PAH in the extracts, which was confirmed by GC/MS analysis. Retene was detected at considerably higher concentrations than other PAH. These data support the use of the RGS assay to detect the presence of CYP1Ainducing compounds, including retene as well as dioxins and furans, in sediments near pulp mills.

Keywords::

• Pulp And Paper Retene Cyp1a Dioxins