Abstract:
This research was conducted to study the distribution of endosulfan metabolites using a nuclear technique. C-14 endosulfan sulfate and C-14 endosulfan diol were used as tracers. Three cement lysimeters of 25 cm in diameter filled with Rangsit soil up to 20 cm were set up and the water level was kept at 5 cm from the soil surface. Golden Apple snails were reared in the paddy field and the rice strain Supanburi I was used in this experiment. Each compound was put in separate lysimeters. The rice seedlings were grown in each lysimeter for 132 days until grain harvesting when C-14 endosulfan sulfate and C-14 endosulfan diol were analysed. The residual compounds were detected from water, dead snails, plant and soil samples. The residue of endisulfan sulfate and endosulfan diol in water decreased rapidly to 1.25 percent and 17.52 percent of initial concentration within 1 day. The residue stability of endosulfan sulfate and endosulfan diol has altered slightly to 0.24 percent and 11.79 percent of initial concentration within 75 and 3 days. When considering distribution of endosulfan metabolite in water, endisulfan sulfate was less well distributed than endosulfan diol. The residue of endosulfan sulfate in dead snails decreased rapidly as well. However, the residue of endosulfan diol in snails changed only slightly whereas the detected amount was 0.07 percent and 0.89 percent of initial concentration within 131 days. The residue of endosulfan sulfate in rice plants increased during the time of growing. The detected amount was 3.73 percent of initial concentration within 132 days. The residue of endosulfan sulfate and endosulfan diol in soil was 73.68 percent and 72.88 percent of initial concentration within 132 days. The distribution of endosulfan sulfate and endosulfan diol in all components were 93.42 percent and 90.68 percent of initial concentration.