Transformation rate of methyl isothiocyanate and 1,3-dichloropropene in water-saturated sandy subsoils.

The transformation rates of methyl isothiocyanate and 1,3-dichloropropene were studied in four water-saturated sandy subsoil materials collected between 2 and 4 m below the soil surface, using laboratory incubation systems at 10 degrees C. In three samples, transformation of methyl isothiocyanate was rapid (< 10% remaining after 30 days), whereas in the fourth, a half-life of ~ 35 days was found. In the transformation of the (Z)- and (E)-isomers of 1,3-dichloropropene in the same materials, half-lives between 16 and 64 days were found. Incubation in systems where the subsoil materials had been exposed unintentionally to temperatures up to 30 degrees C before adding the compounds, resulted in much lower transformation rates for methyl isothiocyanate (half-lives ranging from 150 to 570 days) and in only slightly lower rates for (Z)- and (E)-1,3-dichloropropene (half-lives ranging from 38 to 76 days). (Abstract retrieved from CAB Abstracts by CABI’s permission)