Organotin Compounds in Surface Sediments of Sundarban Wetland and Adjacent Coastal Regions

Abstract

Assessment of sediment quality is of prime importance for proper management of marine environment as required by the Water Framework Directive (2000/60/EC) (WFD) and Marine Strategy Framework Directive (2008/56/EC) (MSFD) that considered sediment as the crucial component for sound management of water bodies. Organotin compounds (tributyltin (TBT), dibutyltin (DBT), monobutyltin (MBT), and triphenyltin (TPhT)) are widely used as active ingredients in marine antifouling coating to resist the settlement of biofouling agents. The chapter explores the quantification and speciation of butyltin contamination levels in surficial intertidal sediments of Indian Sundarban mangrove wetland as well as adjacent Hooghly (Ganges) estuary. Concentration of TBT, DBT, and MBT exhibited a wide range of variations for 16 studied stations of diverse environmental stresses. The correlation coefficient values showed positive significant values between the compounds as follows: MBT and DBT (r = 0.62; p = 0.01) and DBT and TBT (r = 0.54; p = 0.03). The degradation of TBT assessed by BT degradation index (BDI) revealed recent input of BTs at eight studied stations and very recent degradation or absolutely no degradation at four other stations. Based on Australian sediment quality guidelines (SQGs), it is revealed that TBT concentrations in majority of study sites are high and to be considered as potential threats for sustenance of benthic organisms.