有機磷殺蟲劑陶斯松在土壤中之消失

顏瑞泓   羅復興   王一雄^*

國立台灣大學農業化學系

        本研究以三種不同性質土壤，在不同溫度下探討殺蟲劑陶斯松在殺菌及不殺菌狀況下之殘留及發生促進性分解作用 (Enhanced degradation) 的情況。結果顯示在不殺菌處理下陶斯松隨溫度升高而加速其分解消失，其在 25℃ 及 35℃ 時半生期在平鎮 (PC) 系土壤中由 28 天降至 2 天；在鹿港 (LK) 系土壤中由 15 天降至 3 天；在太康 (TK) 系土壤中則由 12 天降至 7 天。殺菌處理結果，在 25℃ 培育下陶斯松在平鎮、鹿港及太康系土壤中之半生期分別為 25、46 及 25 天，與不殺菌處理結果比較之﹐顯示陶斯松在鹿港及太康系土壤中之分解受生物性作用影響，而在平鎮系土壤中主要受非生物性作用所影響。在 25℃下﹐殺菌處理且在密閉系統中試驗結果，陶斯松的半生期在平鎮、鹿港及太康系土中分別為 110、 45 及 54 天，顯示陶斯松在平鎮系土中的主要消失途徑為揮發因子及氧化作用所影響﹐在鹿港系土壤中的消失以生物性分解作用為主，而在太康系土壤中則同時受兩者所影響。此外，陶斯松在三種土壤中進行促進性分解作用試驗時發現，陶斯松之施用並不會誘發促進性分解作用，而且施用藥劑間隔時間的長短，也沒有影響到陶斯松在土壤中的消失速率。

 關鍵字: 陶斯松﹐土壤﹐消失﹐促進性分解。

Dissipation of Organophosphorus Insecticide

Chlorpyrifos in Soils

Jui-Hung Yen, Fook-Hing Law and Yei-Shung Wang^*

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

        The purpose of this studies was to investigate the persistence and enhanced degradation situation of organophosphorus insecticide chlorpyrifos in both autoclaved and unautoclaved conditions of soil samples at different temperatures.   The dissipation rate of chlorpyrifos was increased from 25 to 35℃ in unautoclaved soils.   With increasing the incubation temperature from 25 to 35℃, the half-lives decreased from 28 to 2 days, 15 to 3 days and 12 to 7 days for Pin-Chen (PC), Lu-Kung (LK) and Tai-Kang (TK) soil, respectively. The half-lives were 25, 46 and 25 days in PC, LK and TK soil, respectively, at 25℃in autoclaved soils.   The results imply that the dissipation of chlorpyrifos was affected by biological degradation in LK and TK soils, but not in PC soil.   When autoclaved soils in a closed condition, the half-lives of chlorpyrifos were 110﹐45 and 54 days, respectively, at 25℃.   The results showed that volatilization and oxidation may be the major pathway of chlorpyrifos dissipation in PC soil, microbial degradation may be the major pathway in LK soil and all the actions were occurred in TK soil.   Besides, there are no enhanced degradation of chlorpyrifos was observed in those three soils.

Key words: Chlorpyrifos, Soils, Dissipation, Enhanced degradation.