除草劑全滅草在環境中之移動與消失

 Movement and dissipation of herbicide chlornitrofen in the environment

顏瑞泓、張富翔、王一雄

 國立臺灣大學農業化學系

        全滅草在土壤中消失主要之途徑為水解作用。而在水中全滅草之消失，則包含了生物性分解及化學性水解。在pH 7.8的水中其半衰期僅有25天，pH 7時其半衰期則達45天。溫度影響全滅草在土壤中之吸附作用，在35℃ 時全滅草被土壤吸附量較25℃ 時為低。全滅草在三種土柱中之移動均極為緩慢，在60天淋洗過程中，全滅草僅分佈在土柱上層0至6公分處。以地下水污染潛能模式 (Ground water pollution potential model，GWP) 評估全滅草造成地下水污染之可能性，在陽明山土、岸內土及平鎮土三種土壤中全滅草到達3公尺深處所需之時間分別為34.9、17.4及9.5年，屆時全滅草之殘留量均為零，故不會污染到地下水。

關鍵詞 : 全滅草、土壤、移動與消失、地下水污染潛能模式

   Chemical hydrolysis was the major reaction for dissipation of chlornitrofen in the soil.   Biodegradation and hydrolysis were the reactions found in the river water.   The half life of chlornitrofen in the water was 25 days at pH 7.8 and 45 days at pH 7.0.   The adsorption of chlornitrofen on soil at 35℃ was higher than that at 25℃.   The GWP model (Ground water pollution potential model) was used to assess the possibility of chlornitrofen to pollute the ground water.   The result indicated that it would take 34.9, 17.4, and 9.5 years in Yang-ming San, An-nae, and Ping-cheng soils, respectively, for the chlornitrofen to reach 3 m depth from the surface of the soils.

key words : Chlornitrofen、Soils、Movement and dissipation、GWP model