Spatial distribution of butyltin and phenyltin compounds on the Huelva coast (Southwest Spain)

Six organotin species -tributyltin (TBT), dibutyltin (DBT), monobutyltin (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−1 as Sn, dry weight basis) and seawater (up to 100 ng L−1) 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).