The use of cholinesterase activity in flounder (Platichthys flesus) muscletissue as a biomarker of neurotoxic contamination in UK estuaries

This study investigated the occurrence and levels of neurotoxic contaminati on in UK estuaries by the determination of cholinesterase (ChE) activity in the muscle of the Bounder (Platichthys flesus). Samples were obtained from 16 sites in the estuaries of the rivers Humber, Mersey, Tamar, Tees and Ty ne, ChE activity levels were compared to those at a reference site- the Riv er Aide, Suffolk, Twelve sites exhibited significantly (p < 0,05) reduced C hE activity. The Tyne estuary showed a strong gradient of effect that sugge sted a source of neurotoxic-contamination upstream of the sampled sites. Re presentative water samples from several of the estuaries were analysed for the presence of 32 organophosphate (OP) and 20 carbamate (C) pesticides fro m which residues of nine OPs and six Cs were detected. Correlation analysis of ChE activity with gender, size, GSI, HSI and condition factor suggested that these variables did not influence neural activity in this study. It w as concluded that the reduction in ChE activity was contaminant mediated an d that OP and C pesticides were probable contributors. Influences on ChE ac tivity, higher order implications and its use as a monitoring tool, includi ng reactivation techniques, are discussed. Crown Copyright (C) 2000 Publish ed by Elsevier Science Ltd. All rights reserved.