USDA-ARS, Salinity Laboratory, 450 West Big Springs Road, Riverside, California 92507, United States.
Environ Sci Technol. 2013 Nov 19;47(22):13047-52. doi: 10.1021/es403954z. Epub 2013 Nov 6.
Although long-regarded as an excellent soil fumigant for killing plant pests, methyl bromide (MeBr) was phased out in 2005 in the USA, because it can deplete the stratospheric ozone layer. Iodomethane (MeI) has been identified as an effective alternative to MeBr and is used in a number of countries for preplant pest control. However, MeI is highly volatile and potentially carcinogenic to humans if inhaled. In addition, iodide anions, a breakdown product of MeI, can build up in fumigated soils and potentially cause plant toxicity and contaminate groundwater via leaching. In order to overcome the above two obstacles in MeI application, a method is proposed to place reactive bags containing ammonium hydroxide solution (NH4OH) on the soil surface underneath an impermeable plastic film covering the fumigated area. Our research showed that using this approach, over 99% of the applied MeI was quantitatively transferred to iodide. Of all the resulting iodide, only 2.7% remained in the fumigated soil, and 97.3% was contained in the reactive bag that can be easily removed after fumigation.
尽管甲基溴（MeBr）长期以来一直被认为是一种优良的土壤熏蒸剂，可用于杀死植物害虫，但由于其会消耗平流层中的臭氧，因此已于 2005 年在美国被逐步淘汰。碘甲烷（MeI）已被确定为 MeBr 的有效替代品，并在许多国家用于种植前的虫害防治。然而，MeI 极易挥发，如果被吸入，对人类具有潜在致癌性。此外，MeI 的分解产物碘化物阴离子会在熏蒸的土壤中积聚，并可能导致植物毒性和通过淋滤污染地下水。为了克服 MeI 应用中的上述两个障碍，提出了一种在覆盖熏蒸区域的不渗透塑料薄膜下的土壤表面放置装有氨水溶液（NH4OH）的反应袋的方法。我们的研究表明，使用这种方法，超过 99%的施用 MeI 被定量转化为碘化物。在所有生成的碘化物中，只有 2.7%残留在熏蒸土壤中，97.3%存在于反应袋中，熏蒸后可轻松将其去除。
