~(14)C-杀螟松在模拟稻/鱼生态系统中的残留

应用~(14)C-杀螟松研究该农药在模拟稻/鱼生态系统中的残留与分布表明:在稻田水和稻株茎叶中的残留浓度随时间增长而逐渐消减:在土壤、稻株、根系和鱼体中为前期增加,到一定时期后开始衰减。水稻收获期测定,在高剂量处理的稻田水、上层土壤、下层土壤、稻茎叶、糙米和鱼体中、其残留浓度分别为0.0027、0.4994、0.0993、4.2429、2.1024和4.3400ppm;在低剂量处理申,除稻田水未检测出外,分别为0.2653、0.0380、1.7818、0.9633和2.1469ppm。在土壤和稻株中结合态残留物所占比例高达60—90％,且有随时间而增加的趋势

RESIDUES OF ~(14)C-FENITROTHION IN A SIMULATED RICE/FISH ECOSYSTEM

Residues and distribution of 14C-fenitrothion in a simulated rice/fish ecosystem were studied.The pesticide was sprayed in low ( X,X=116mg available ingredient/1.08m2 ) and high (2X) doses on the rice plants.The results showed that residues of the pesticide in the flooded water and the leaves and stems of the rice plants decreased with time course but increased in the soil,fish and roots of the plants in early stage and decreased thereafter.At harvest,concentrations of fenitrothion remained in different parts of the ecosystem were as follows;flooded water,0.0027ppm (2X);upper parts of the soil,0.2653ppm (X) and 0.4994ppm (2X);lower parts of the soil,0.0380ppm (X) and 0.0993ppm (2X):unpolished rice,0.9633ppm(X) and 2.1024ppm(2X):leaves and stems of the plants,1.7818ppm (X) and 4.2429ppm(2X);fish,2.1469ppm(X ) and 4.3400ppm (2X).About 60-90% of the pesticide remained in the soil and rice plants were bound residues which tended to increase with the lapse of time.