Cadmium and organotin pollution in an estuarine environment from Argentina: an overview

Abstract

Total heavy metal concentrations have been monitored for almost thirty years, while organotin compounds have only been evaluated in the last few years. Intertidal as well as subtidal surface sediments were fully analyzed and the corresponding results are included in this review. Cadmium contents within sediments were slightly higher close to the area where the industrial effluents are discharged, as well as near the harbour zones during the study period. The analysis revealed that ?with the exception of the last analyzed period- cadmium is at background concentrations within the study system. A permanent monitoring programme within the inner zone of the estuary has demonstrated that cadmium concentrations slightly increased during the study period, indicating a regular input of these metals into the system. In addition, recent studies have shown similar contents of cadmium on both tidal flats and sub-tidal sediments within the estuary. Organotin compounds (DBT and TBT) were found in sediments of the entire studied area. Their concentrations ranged from very low values within low impacted areas to higher ones next to the most active harbour facilities. The highest amounts of both DBT and TBT were recorded in the neighbourhood of dry docks where careenage of ships may be the main source. These results throw light upon the process of accumulation of cadmium and organotin compounds within the analyzed sediments, allowing us to conclude that the inner area of the estuary could be considered an intermediate polluted system.