Hepatic EROD activity in flounder (Platichthys flesus) as an indicator of contaminant exposure in English estuaries

To in investigate the presence of sub-lethal contaminant effects in flounde r (Platichthys flesus) populations in English estuaries, 16 sites from 7 es tuaries were sampled in September-December 1997. Determination of hepatic e thoxyresorufin O-deethylase (EROD) activity revealed that significant (p < 0.05) induction of the mixed function oxygenase (MFO) system was apparent i n flounder from several industrialised estuaries compared to the relatively unpolluted reference site - the Aide estuary, The estuaries in increasing order of observed mean EROD activity were: Aide, Southampton Water, Humber, TS ne, Wear, Tees, Mersey, No significant gender differences in EROD induc tion or other measured variables were discovered for any site, Limited anal ytical data suggest a close link with EROD induction and hepatic polycyclic aromatic hydrocarbons (PAH)/polychlorinated biphenyls (PCB) concentrations but no strong correlations were discovered between EROD activity induction with any other measured variable across all estuaries. However, in the Tyn e estuary strong negative correlations,were discovered bean een mean female EROD and female gonado-somatic index (GSI) and female condition factor (CF ) of r = -0.84 and -0.80, respectively. It is suggested that the 'out of se ason' correlation of reproductive parameters with EROD could be linked to c ontaminant interference, perhaps by xeno-oestrogens, It is clear that floun der populations in English industrialised estuaries are exhibiting widespre ad sub-lethal contaminant effects and more research is essential to underst and the potential implications of this for reproduction and disease that co uld be affecting the future viability of these populations. Crown Copyright (C) 1999 Published by Elsevier Science Ltd. All rights reserved.