PERSISTENT ORGANOCHLORINE PESTICIDE-RESIDUES IN GREEN MUSSELS (PERNA-VIRIDIS) FROM THE GULF OF THAILAND

Concentrations of BHCs (alpha, beta, gamma, and delta isomers), HCB, a ldrin, dieldrin, endrin, heptachlor, heptachlor epoxide, and DDT compo unds (o,p'- and p,p'-isomers of DDT, DDD, and DDE) were determined in green mussels (Perna viridis) collected from nine locations along the coastal area of the Gulf of Thailand in May 1991. Residues of aldrin, dieldrin, and DDT compounds were detected in all samples. The other pe sticides were found either at very low concentrations in a few samples or below detection limits. Non-DDT pesticide levels found in the pres ent study showed a decrease, whereas DDT compounds seemed to remain un changed in the average values in comparison to the data of the previou s study conducted 2 years earlier.