Organotin compounds in surface and pore waters of Ganga Plain in the Kanpur-Unnao industrial region, India

Abstract

Organotin compounds (OTCs) belong to those chemicals most toxic to the aquatic organisms which are deliberately introduced into the aquatic system through anthropogenic activities. Various species of organotin compounds were detected in surface and pore waters of the Ganga Plain in Kanpur-Unnao industrial region in pre-and post-Monsoon periods of 1995. The extraction of these compounds was performed using a method of direct aqueous phase in situ ethylation with sodium tetraethylborate (NaBEt4). After extraction into hexane, they were detected by GC-MIP-AED. The water of this area is contaminated with dimethyltin (DMT), monobutyltin (MBT), dibutyltin (DBT) and tributyltin (TBT) compounds. Concentrations of these compounds in surface water of the pre-Monsoon period of 1995 range from 2.1 to 70.1 ng Sn/l for MBT, 1.7-101.1 for DBT and 2.9-19.8 for TBT, whereas in pore water; 9.7-23.5 ng Sn/l for MBT, 11.2-18.0 for DBT and 8.7-32.6 for TBT. However, in the post-Monsoon period of 1995, surface water shows considerable decrease in concentrations: DMT below detection-1.8 ng Sn/l, DBT 3.0-5.4, TBT 3.1-3.6 and MBT is below detection. This study is a preliminary documentation of water pollution by OTCs in the Kanpur-Unnao region of the Ganga Plain and suggests the necessity of further detailed OTCs studies in other regions of the Ganga Plain.