Release of Carbofuran from Granular Formulations in Water and Its Degradation Patterns in Soils

Carbofuran 입제(粒劑)의 수중용출(수중용출)과 토양중(土壤中) 분해특성(分解特性)

Experiments were carried out with purified technical grade and two types of impregnated and sand-coated granules of carbofuran, in order to investigate the release patterns in water and the persistence of this chemical in soils. The results obtained are summarized as follows: 1) As regards to release velocity in water, impregnated granule was found to be faster than sand-coated granule. The time to reach maximum concentrations of carbofuran in water from technical carbofuran, impregnated granule and sand-coated granule was 0.5, 3 and 5 days, respectively. 2) Degradation rate of carbofuran in soils decreased in the order of technical carbofuran, impregnated granule, sand-coated granule regardless of soil types and application rates. Degradation of carbofuran in flooded soil was faster than in non-flooded soil. Soil flooding appeared to be the main factor in promoting the degradation of carbofuran in the soil. 3) When carbofuran was fortified in soils in the form of technical carbofuran, impregnated granule or sand-coated granule, the persistencies of two terminal residues of carbofuran, that is, 3-hydroxy carbofuran and 3-keto carbofuran decreased in the order of sand-coated granule, impregnated granule and technical form.

제제형태(製劑形態)에 따른 carbofuran의 수중용출속도와 토양중 잔류소장(殘留消長)을 조사하기 위하여 재결정 하여 정제한 carbofuran 원제와 시판(市販) sand-coated granule 및 실험실에서 립상(粒狀)규조토를 담체(擔體)로 제조한 impregnated granule을 공시(供試)하여 시험한 결과는 다음과 같다. 1) Carbofuran의 수중용출속도는 원제impregnated granule> sand-coated granule 순(順)이었으며 3-hydroxy carbofuran과 3-keto carbofuran의 잔류기간도 입제 처리가 원제 처리시 보다 더 길었다. 또한 토양별로 보면 담수 사양토가 비담수 양토에서 보다 carbofuran과 그의 두 대사산물인 3-hydroxy carbofuran과 3-keto carbofuran의 잔류기간이 짧았는데 이는 담수 여부가 토양 중 carbofuran의 분해에 주요한 인자임이 증명되었다. 3) 두 종류의 carbofuran 입제 처리시 3-hydroxycarbofuran과 3-keto carbofuran이 최고 농도에 이르는 기간은 각각 $40{\sim}80$일, $20{\sim}40$일 소요되었으며 입제의 종류별로 보면 impregnated granule 처리가 sandcoated granule 처리보다 3-hydroxy carbofuran과 3-keto carbofuran의 잔류기간이 짧았다.