Assessment of Insecticide Carbofuran to Contaminate Groundwater through Soils in Subtropics

 

JUI-HUNG YEN, FANG-LAN HSIAO AND YEI-SHUNG WANG*

Department of Agricultural Chemistry, National Taiwan University, Taipei, Taiwan

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 The possible contamination of groundwater by insecticide carbofuran was assessed with behaviour assessment model (BAM) and ground water pollution-potential model (GWP).  Dissipation coefficient of this insecticide in two subtropical soils at different moisture contents and soil temperatures were studied by determining the degradation and adsorption of the herbicide in soils.  Movement of carbofuran was studied by leaching the insecticide in soil column in the laboratory.  Under 40% field capacity and at 25¢J, more than 80% of carbofuran residue was found in both Luchu clay and Yuanlin silty clay loam after incubation for 63 days.  The results showed the more the moisture content in the soil, the less the carbofuran residue under the soil moisture below the field capacity.  Carbofuran tends to dissipate easily in Yuanlin soil than in Luchu soil.  The distribution coefficient (Kd) with r2 of 0.69 and 0.92 for Luchu and Yuanlin soils, respectively, was found from the first-order kinetics law.  In leaching experiment, carbofuran showed easy movement in Luchu than in Yuanlin soil.