Using the metabolism of PAHs in a human cell line to characterize environmental samples

P450 reporter gene system (RCS) is an in vitro assay to detect compounds th at activate the Ah receptor and induce cytochrome P450 (CYP1A1). This syste m utilizes a human cell (101L) stably transfected with a luciferase reporte r downstream of human CYP1A1 promoter sequences. When CYP1A1-inducing compo unds are present, luciferase is produced as well as endogenous CYP1A1 enzym es. Polycyclic aromatic hydrocarbons (PAHs) are more readily degraded than chlorinated compounds including dioxins, furans, and coplanar polychlorinat ed biphenyls (PCBs). PAM-induced luciferase production begins to decrease b etween 6 and 16 h, while chlorinated compounds produce a more sustained res ponse. Individual and mixtures of CYP1A1-inducing compounds were tested at both 6 and 16 h. Extracts of soils containing both PAHs and dioxins were al so tested, before and after cleanup to remove PAHs. Results indicate that R GS testing at 6 and 16 h is a promising tool to differentiate between PAHs and chlorinated hydrocarbons often co-occurring in environmental samples. ( C) 2000 Elsevier Science B.V. All rights reserved.