Laboratory Assessment of Emission Reduction Strategies for the Agricultural Fumigants 1,3-Dichloropropene and Chloropicrin

Authors: Ashworth, Daniel; ERNST, FRED - University Of California; XUAN, RICHENG - University Of California; Yates, Scott

Submitted to: Journal of Environmental Science and Technology
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 5/1/2009
Publication Date: 7/1/2009
Citation: Ashworth, D.J., Ernst, F.F., Xuan, R., Yates, S.R. 2009. Laboratory Assessment of Emission Reduction Strategies for the Agricultural Fumigants 1,3-Dichloropropene and Chloropicrin. Journal of Environmental Science and Technology. 43(13):5073-5078.

Interpretive Summary: The use of fumigants enables growers to obtain high yields of specialty crops, such as strawberries and carrots; and produce a large economic return. Fumigants, however, are easily lost from soil to the atmosphere where they negatively impact regional air quality. To reduce fumigant emissions, often the soil is covered with a high density plastic film. Other methods to reduce emissions, such as sprinkler irrigation, use of soil amendments haven’t been fully tested in agricultural fields. There is a need to quantify fumigant emissions when the soil surface is covered with new improved plastic films (i.e., virtually impermeable) and for situations where soil amendments are used (i.e., ammonium thiosulfate, organic material). Therefore, this work reports on laboratory experiments to test new emission reduction strategies and carry out preliminary quantification of the emissions of the soil fumigant 1,3-dichloropropene and chloropicrin. As far as possible, field conditions were maintained in the experiments. Total emissions of around 40 % (of the total added) were observed in the absence of any emission reduction strategy. The data showed very good reproducibility between replicates providing confidence in the experimental results. Reduction in 1,3-D emissions greater than 80% were observed for a virtually impermeable film and when amending the soil surface with composed municipal green waste material. Emission reductions greater than 40% were observed when wetting the soil surface using sprinkler irrigation; with or without a fertilizer amendment (i.e., ammonium thiosulfate). The reported research offers an inexpensive alternative to studying fumigant emissions from large agricultural fields, and suggests that highly impermeable tarps or reactive organic material would be required to drastically reduce emissions.

Technical Abstract: With the increased use of the agricultural fumigants 1,3-dichloropropene (1,3-D) and chloropicrin (CP), it is important that strategies to reduce emissions of these fumigant from soil to the air are assessed to protect air quality. Using an established soil column approach, the following emission reduction strategies were compared to a control: (1) spray application of ammonium thiosulfate to the soil surface; (2) deep injection at 46 cm depth; (3) high density polyethylene sealed over the soil surface; (4) virtually impermeable film sealed over the soil surface; and (5) irrigation with ammonium thiosulfate solution. Relative to the control, 1,3-D emissions were reduced by 26.1, 1.0, 0.01, 94.2, and 42.5%, for treatments 1 through 5, respectively. For CP the reductions were 41.6, 23.3, 94.6, 99.9, and 87.5% for treatments 1 through 5, respectively. Virtually impermeable film gave the greatest reductions for both fumigants, while HDPE was very effective only for CP. Despite offering less significant emission reductions, the lower cost alternatives to tarping, particularly irrigation with ATS solution, may offer substantial benefit where tarping is not economically viable.