14C-呋喃丹农药在水稻-土壤生态系统中迁移和归宿的研究

研究了~(14)C-呋喃丹在水稻-土壤系统中的吸收、分布、迁移、转化,结果表明,呋喃丹随时间逐渐蓄积于水稻叶尖及边缘,而稻穗部位迁移甚微,收割后糙米中母体残留量仅为0.003ppm.在稻田土、水稻植株、水生植物中主要转化产物为结合态,蜗牛中则以代谢产物为主.呋喃丹有向土壤深层转移的趋向,其转化产物比母体有更强的渗透性,水生植物有较强吸收和富集能力,并很快转化代谢.

FATE OF 14C-CARBOFURAN IN RICE PLANT-SOIL ECOSYSTEM

The fate of 14C-carbofuran in rice plant-soil ecosystem were studied under field conditions. Significant accumulation of carbofuran residues at leaf margin was observed, while very little was accumulated in grain ears.The bond compounds were 71.50, 60.62,81.78 and 25.44% respectively for soil, rice plant, duckweed and snail, in which the major residue was metabolite. About 60%of the residues in soil was retained in surface horizon and the degradation products were more permeable. 0.0002% of the 14C-radioactive residues was detected in groundwater under 40cm layer ' of the paddy soil. Carbofuran in paddy water was concentrated and transformed in duckweed quickly. The degradation pathways of the chemical was hydroxylation in soil and oxidation in rice plant in which the conjugate first undergoes hydroxylation at the number 3 carbon atom and then transforms to bond compounds.