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Title: ACCELERATED DEGRADATION OF METHYL ISOTHIOCYANATE IN SOIL

Author
item Dungan, Robert - Rob
item GAN, JIANYING - UC RIVERSIDE, CA
item Yates, Scott

Submitted to: Journal of Water Air and Soil Pollution
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 5/14/2002
Publication Date: 1/1/2003
Citation: Dungan, R.S., Gan, J., Yates, S.R. 2003. Accelerated degradation of methyl isothiocyanate in soil. Journal Of Water Air And Soil Pollution. 142:299-310.

Interpretive Summary: Methyl isothiocyanate is one potential replacement fumigant pesticide for methyl bromide. However, MITC is toxic, highly volatile, and has the potential to contaminate the atmosphere. The primary goal of this research is to minimize the atmospheric emission of MITC after agricultural use. One method to reduce fumigant emissions is to enhance their in situ degradation by incorporating organic amendments into the soil surface. This study investigates the effects of temperature and the application of chicken manure on the degradation of MITC. Adding organic material to soil reduces emissions to the atmosphere and provides a method to protect our air from contamination.

Technical Abstract: Methyl isothiocyanate (MITC) is a primary breakdown product of metam-sodium. MITC is toxic and has a high potential for volatilization. Therefore, minimizing its atmospheric emission is of the utmost importance. One method to reduce fumigant emissions is to enhance their in situ degradation by incorporating organic amendments into the soil surface. In this study we determined the combined effect of temperature and chicken manure application rate on the degradation of MITC. The degradation of MITC was significantly accelerated by both increasing temperature and amendment rate. Differences between sterile and nonsterile degradation kinetics in unamended and amended soil indicate that MITC degradation is equally controlled by chemical and biological processes. The amelioration of soil with organic amendments should be further considered when designing fumigation practices that allow for reduced emissions.