METHYLATED PAHS AND/OR THEIR METABOLITES ARE IMPORTANT CONTRIBUTORS TO THE OVERALL ESTROGENIC ACTIVITY OF PAH-CONTAMINATED SOILS

Abstract

In this study 42 polycyclic aromatic compounds (PACs) were investigated for their estrogenic potential using the VM7Luc4E2 transactivation assay (VM7Luc4E2-TA). Relative potencies (REPs) were determined for mass-balance analysis. In addition, compounds were tested in combination with the estrogen receptor (ER) antagonist ICI182,780 (ICI) and the Ah receptor (AhR) antagonist/CYP1A1 inhibitor α–naphthoflavone (α-NF). Luciferase induction and CYP1A1-dependent EROD-activity were measured to assess if the estrogenic activity was elicited by the compound itself and/or by its metabolites. REPs ranged between 10⁻⁷ and 10⁻⁴. The ability of ICI to decrease luciferase activity stimulated by all compounds indicated that the induction responses were ER-dependent. α-NF decreased luciferase induction and EROD-activity by several compounds, including as the methylated chrysenes, suggesting that metabolites of these chemicals contributed to ER activation. Several PACs, such as acridine and its derivatives, appear to directly activate the ER. Furthermore, extracts of soils from industrial areas were examined using this bioassay and estrogenic activity was detected in all soil samples. Mass-balance analysis using a combination of REPs and chemical analysis of the samples suggested that polycyclic aromatic hydrocarbons (PAHs) and alkylated PAHs, such as 1- and 3-methylchrysene, are important contributors to the overall estrogenic activity. However, these results revealed that a considerable proportion of the estrogenic activity in the soil remained unexplained, indicating the presence of other significant estrogenic compounds. This article is protected by copyright. All rights reserved

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