Pergamon Chemosphere, Vol. 31, No. 5, pp. 937-950, 1998 0 1998 Elsevier Science Ltd p11: soo45-6535(98)00096-4 All rights reserved. Printed in Great Britain 0045-6535/98 $19.00+0.00 SPATIAL DISTRIBUTION OF BUTYLTIN AND PHENYLTIN COMPOUNDS ON THE HUELVA COAST (SOUTHWEST SPAIN) J.L. Gomez-Ariza’, E. Morales and I. Giildez Departamento de Quimica y Ciencia de 10s Materiales, Escuela Politthica Superior, Universidad de Huelva, 21819 LA RABIDA, Huelva (Spain) (Received in Germany 22 October 1997; accepted 27 February 1998) ABSTRACT. Six organotin species -tributyltin (TBT), dibutyhin (DBT), monobutyhin (MBT), triphenyltin (TPT), diphenyltin (DPT) and monophenyltin (MPT) have been determined in seawater and sediments collected from some representative enclosed areas of the southwest Spain. No phenyltin species were found in waters showing the absence of recent inputs of these species. However, butyltin species were present in all the stations along the Huelva coast. The highest TBT levels were found in sediments (up to 195 ng g“ as Sn, dry weight basis) and seawater (up to 100 ng L’) in harbours and marinas, closely related with boating activity and decreasing according to the distance from the potential sources. Results make possible to establish conclusions about the critical ecological consequences of organotin presence in this area, where shell-fish farms, fishery activity and migrating birds might be at risk. Different TBT degradation rates were found in sediments collected in winter (Cadiz coast) and in summer (Huelva coast). 01998 Elsevier Science Ltd. All rights reserved keywords: Organotin compounds, coastal waters, sediments, speciation, south-west Spain INTRODUCTION. Organotin compounds, generally used for industrial and agricultural (biocides) purposes as well as for marine structures (antifouling paints) have important environmental consequences, due to their toxicity [l]. Levels of TBT of 2 ng L-’ inhibit calcification in Crussostrea gigus [2] and induce imposex in the dogwhelk Nucellu fupillus, producing a deleterious effect on reproduction [3]. The quality standard value (EQS) for TBT in water was re-set at 2 ng L-’ in 1988, in order to achieve a complete protection of marine life [4]. Several monitoring programmes developed in coastal areas of several countries have revealed the TBT declination as a consequence of organotin regulations [5-71. Although, TBT concentrations in water have usually been used to establish the Water Quality Index, several authors have pointed out that significant 937