混合农药对拟除虫菊酯杀虫剂在水中光解的敏化和猝灭效应研究

研究了哒嗪硫磷、西维因、克百威、除草醚和丁草胺对氯氰菊酯、溴氰菊酯和氰戊菊酯在水中光解的光敏化或光猝灭效应.除草醚对三种拟菊酯杀虫剂在水中的光解有极强的光敏效应,在0.1:1—10:1的剂量比范围内,光敏效率与剂量比显著正相关;哒嗪硫磷和西维因对氯氰菊酯和溴氰菊酯以及高剂量比(10:1)时对氰戊菊酯在水中均表现显著的光敏效应.在过滤灭菌的塘水和田水中,丁草胺对3种拟菊酯杀虫剂的光猝灭效应和哒嗪硫磷的光敏效应比在重蒸馏水中显著增强;在pH缓冲液中,克百威光猝灭效应明显,而在重蒸馏水中这种效应消失,其它4种混合农药的光敏或光猝灭效应比在重蒸馏水中不同程度地增强;除草醚的光敏效应随pH增大而稍有减弱,西维因则随pH增大而显著增强.

THE SENSITIVITING AND QUENCHING EFFECTS OF SELECTED PESTICIDES ON PHOTODEGRADA-TION OF PYRETHROID INSECTICIDES IN WATER

The sensitiviting and quenching effects of five pesticides on photodegra-dation of pyrethroid insecticides were studied under sunlight. Nitrofen, car-rbaryl, and pyridaphenthione have been found to be strong photosensitizer, butachlor and carbofuran to be photoquencher of cypermethrin, deltamethrin and fenvalerate in water. There was significant correlation between the efficiency and the concentration. The photosensitizing effect of nitrofen was positively related to the concentration ratio between nitrofen and three pyriethroid. The photoquenching effect was stronger for butachlor in paddy water than that in redistilled water. An intense photoquenching effect for carbofuran showed in phosphate buffers but not in redistilled water. The photosensitive efficiency of carbaryl increased sharply with the pH value of buffer solutions, while a light decrease of the efficiency for nitrofen with increase of pH was observed.