PARENT SESSION
4H Ecological risk assessment for the marine environment
9:00 AM to 7:00 PM, Wednesday, 09 May 2001

(W/EH083) Concentrations of PCBs, HCHs, DDTs and organotins in Indian marine environment.

Ramaswamy, Babu Rajendran^1,2, Imagawa, Takashi¹, Tao, Hiroaki¹, Miyazaki, Akira¹, Ramachandran, Ramesh², Sundarajan, Ramachandran², ^{1 2}

ABSTRACT- Analyses of environmentally persistent pollutants like polychlorinatedbiphenyls (PCBs), hexachlorocyclohexane (HCH) isomers, dichlorodiphenyltrichloroethane (DDT) compounds and organotins (OTs) were carried out using HRGC-HRMS and GC/ICP-MS, respectively in seawater and sediment samples collected during 1998 and 1999 from nine locations along south east coast of India. Sediments and water from Chennai harbour and Cuddalore fishing harbour contains high concentrations of PCBs and pesticide residues. Very high concentration of total PCB was quantified in sediment from Chennai harbour (6570 pg/g dry weight) followed by a sediment sampled near Cooum River mouth (505 pg/g dry wt.), Cuddalore fishing harbour (335 pg/g dry wt.) and Mandapam (251 pg/g dry wt.). Concentrations in other sediments were an order of magnitude lower than Cuddalore fishing harbour and two order of magnitude lower than Chennai harbour. A distinct distribution pattern of PCBs in sediment was observed between harbours and other locations. Greater concentrations of tetra, penta and hexachlorobiphenyls were observed in sediments of harbours and near river mouth, but in other locations di, tri and tetrachlorobiphenyls were found more. Seawater concentration of HCH was higher than DDT, but it is quite opposite in sediments. Apart from harbour sediments slightly elevated concentrations of HCH were also observed in few other locations. But, increased level of DDT was observed only in harbour/nearby sediments and not from other locations. This reflects the usage pattern and local input of these pesticides. Among organotins, butyltins (MBT, 1.6-393; DBT, 1.3-394; TBT, not detected-1280 ng Sn/g dry wt.) alone were detected in sediments from harbour environment, but not phenyl- or octyltins. In seawater, octyltins were also determined in addition to butyltins. PCBs and pesticide residue levels were more in harbour areas and near Cooum river mouth than other places, but organotins were detected only at harbours.

Key words: pollutants, seawater, sediment, India