Persistence and distribution of [~(14)C]malathion in rice-fish model ecosystem

摘要

Study was conducted in model ecosystem with [~(14)C]Malathion as tracer to determine the persistence and distribution of radioactivity in water, soil, fish and rice plant which are the major components of ecosystem. The half life (DT_50) of malathionin paddy water was found to be only 9 days. Highest concentration was recorded on the 2~nd day of the experiment and with progress of time dissipation occured rapidly. By 14 days about 88% was dissipated from the water. Malathion applied to soil was found to be extractable by 96% on the first day and it was decreased to 41% on 90 days. Bound malathion in soil was found to be increased with time from about 4% to 58% by 90 days. In rice plant, highest concentration was contained in leaves followed by stem and then root. Malathion residues in fish was always higher in visceral portion than muscle. Highest concentration of residues 44% in muscle and 56% in viscera were found on 14 days.