Distribution of butyltins in waters and sediments of the Mandovi and Zuari estuaries, west coast of India

Butyltins (TBT, DBT, MBT) were measured in water and sediment samples collected from various locations in the Mandovi (10 stations) and Zuari (9 stations) estuaries during November 2007. The total butyltin (TB) in water samples varied between ~12 and 73 and from 0.5 to 77 ng Sn l-1; whereas, for the sediments it varied from ~ 15 to 118 and 6 to 119 ng Sn g-1 dw for the Mandovi and the Zuari estuaries, respectively. The average TB concentration in the sediments from the Zuari estuary was higher as compared to the Mandovi estuary, whereas for the water samples it was vice versa. For both the water and sediment samples, MBT was generally the most predominant butyltin in these two estuaries. This suggests that the butyltins contamination was not freshly derived. Fairly good relationships between the concentrations of TB and organic carbon in water and sediment samples of these estuaries implicate the importance of adsorption/desorption processes in controlling the levels of TB in these estuaries