Temporal fluctuations of tributyltin in the bivalve Venerupis decussata atfive stations in southwest Spain

Filter feeding clams, Venerupis decussata, were sampled every 4 months for 8 years at five locations on the southwest Spain coast and analysed for org anotins. All the stations showed a significant sinusoidally shaped seasonal evolution pattern for tributyltin (TBT) superimposed upon a linear decreas ing tendency. The amplitude and frequency of fluctuations differed among st ations and were correlated to the harbour activities. Fluctuations were gre atest at stations with the greatest TBT presence. The long-term trend of TB T in clams indicated half-life Values of about 7-14 years. During 1993, wat er and sediment samples were also collected at monthly intervals and analys ed. Correlations between TBT bivalve contents and water concentrations were higher than those found between biota and sediments. (C) 2000 Elsevier Sci ence Ltd. All rights reserved.