CHANGES IN BRANCHIAL NA+,K+-ATPASE, METALLOTHIONEIN AND P450-1A1 IN DAB LIMANDA-LIMANDA IN THE GERMAN BIGHT - INDICATORS OF SEDIMENT CONTAMINATION

Na+,K+-ATPase activity, ouabain binding, metallothionein and P450 1A1 were measured in gill tissue from the dab Limanda limanda caught from a contaminant gradient in the German Bight during the Bremerhaven Workshop. Metallothionein levels were highest at the most contaminated sites closest to the mouth of the Elbe and lowest at the outermost station on the Dogger Bank. Tissue levels of zinc and cadmium were also elevated at these sites but copper levels did not change along the gradient. P450 1A1 levels, measured with dn antibody probe, showed a complex pattern of induction which suggests an inhibitory effect at the most contaminated stations. Na+,K+-ATPase was similar in fish from all of the stations but measurement of ouabain binding show that levels of the enzyme are elevated at the innermost and outer stations. Calculation of activity per binding site indicates that the turnover rates of the enzyme were lower at the most contaminated stations. The results show that the role of adaptive responses in the face of inhibition by contaminants is an important consideration in identifying biological effects. The data were analysed with respect to the contaminant burdens in the total and fine particulate fraction (< 63 mum) of the sediment and in the liver of dab caught at each station. The utility of biological effects measurement in the gill as an indicator of environmental contamination is discussed.