DISTRIBUTION AND FATE OF ~(14)C-DDT IN MICROCOSM EXPERIMENTS SIMULATING THE TROPICAL MARINE ENVIRONMENT OF THE BAY OF BENGAL

摘要

Marine microcosm experiments were conducted in aquaria to study the distribution and fate of ~(14)C-DDT in water, sediment, algae and mussels collected from the Bay of Bengal coast at St. Martin Island in the south of Bangladesh. Samples of water, sediment, algae and mussels from the aquarium were taken at 0 h, 2 h, 4 h, 24 h, 6 d, 14 d and 30 d to determine the ~(14)C-DDT residues. A liquid scintillation counter and a biological oxidizer were used to establish the radioactivity in components of the ecosystem. Thin layer chromatographic techniques were used to study the metabolic transformation of DDT. It was found that DDT translocated from water to sediment, algae and mussels at varying rates. No adverse effects of applying ~(14)C-DDT to biota species were observed. At 0 h, 94% activity was present in water, while 3 and 4% were found in sediment and algae, respectively. The ~(14)C-DDT disappeared gradually from water up to 24 h, followed by a sharp reduction; only 1.5% was present on day 14. Sediment in the aquarium gradually accumulated ~(14)C-DDT, reaching 36% on day 6; thereafter, a decline in activity was observed. Sediment retained substantial activity (more than 20%), even on day 30. Algae accumulated ~(14)C-DDT rapidly from the beginning of the experiment, with maximum values of 30-36% during the 3-6 d period, while some