Mitigating 1,3-dichloropropene, chloropicrin, and methyl iodide emissions from fumigated soil with reactive film

Implicated as a stratospheric ozone-depleting compound, methyl bromide (MeBr) is being phased out despite being considered to be the most effective soil fumigant. Its alternatives, i.e., 1,3-dichloropropene (1,3-D, which includes cis and trans isomers), chloropicrin (CP), and methyl iodide (MeI), have been widely used. High emissions of MeI from fumigated soil likely put farm workers and other bystanders at risk of adverse health effects. In this study, two types of constructed reactive film were tested for their ability to mitigate emissions of 1,3-D, CP, and MeI using laboratory permeability cells. Before activation, these films act as a physical barrier to trap fumigants leaving soil. After activation of the reactive layer containing ammonium thiosulfate solution, the films also act as a sink for the fumigants. Over 97% of trans-1,3-D and 99% of the cis-1,3-D, CP and MeI were depleted when they passed into the reactive film. Half-lives (t(1/2)) of cis-, trans-1,3-D, CP and MeI under activated reactive film were 1.2, 1.4, 1.6, and 2.0 h respectively at 40 °C.