Accelerated transformation of 1,3-dichloropropene in loamy soils.

Abstract

Inadequate nematode control on some loamy soils after fumigation with 1,3-dichloropropene prompted further study of transformation in these soils. The rate of transformation of (Z)- and (E)-1,3-dichloropropene was measured in moist soils incubated at 15 degrees C in fumigant-tight systems. In six loamy soils, transformation was gradual and pseudo first-order during 3 to 6 days but thereafter it was very fast. At an initial content in dry soil of 62-80 mg/kg the remaining amounts were less than 0.2% of the dose after a week. The greatly accelerated transformation after a short time lag suggests that the soils contained microorganisms that can transform 1,3-dichloropropene effectively. The fast transformation was measured in soil from fields once or twice fumigated previously as well as from fields never treated. In one of these loamy soils, a fast transformation (less than 0.2% remaining after 7 days) was measured at initial contents of 3.7, 18 and 92 mg/kg. But when the initial content was 470 mg/kg, the transformation rate was markedly suppressed (half-life 33 days). In another loamy soil, which showed no accelerated transformation patterns, the pseudo half-lives substantially increased from 4.3 to 36 days when the initial content of 1,3-dichloropropene was raised from 3.7 to 470 mg/kg. (Abstract retrieved from CAB Abstracts by CABI’s permission)