DEGRADATION OF 1,3-DICHLOROPROPENE (1,3-D) IN SOILS WITH DIFFERENT HISTORIES OF FIELD APPLICATIONS OF 1,3-D

Laboratory experiments were conducted to determine the mineralization rates of 1,3-dichloropropene (1,3-D) in surface and subsurface soil sa mples collected from three sites in Florida with different histories o f 1,3-D exposure. Mineralization rates of uniformly labeled C-14-1,3-D in surface and subsurface samples collected from two of the three sit es, one of which was treated with 1,3-D only once and the other which had not been treated with the chemical for 5 years, were similar to th e corresponding samples collected from untreated plots, and the rates generally decreased with soil depth. Initial mineralization rates in s urface and subsurface samples collected from the site that had repeate dly been treated with 1,3-D at least 6 of the past 12 years were more rapid than those in either the corresponding untreated samples or in s amples collected from the two other sites. Not only were the initial m ineralization rates in soil samples collected from this site greater, but also the disappearance rates of cis- and trans-1,3-D were greater than in the corresponding untreated samples. Trans-1,3-D was degraded much more rapidly in the enhanced soil than was the cis- form. In addi tion, no or little trans-3-chloroallyl alcohol (CAA), the hydrolysis p roduct of trans-1,3-D, was formed; large amounts of cis-3-CAA, the hyd rolysis product of cis-1,3-D, were detected. This suggest that biologi cal hydrolysis is responsible for the hydrolysis of trans-1,3-D to tra ns-S-CAA in enhanced soil and chemical hydrolysis is responsible for t he hydrolysis of cis- and trans-1,3-D to S-CAA in nonenhanced soil.