Effect of temperature, organic amendment rate and moisture content on the degradation of 1,3-dichloropropene in soil

1,3-Dichloropropene (1,3-D), which consists of two isomers, (Z)- and (E)-1, 3-D, is considered to be a viable alternative to methyl bromide, but atmosp heric emission of 1,3-D is often associated with deterioration of air quali ty. To minimize environmental impacts of 1,3-D, emission control strategies are in need of investigation. One approach to reduce 1,3-D emissions is to accelerate its degradation by incorporating organic amendments into the so il surface. In this study, we investigated the ability of four organic amen dments to enhance the rate of degradation of (Z) - and (E) 1,3-D in a sandy loam soil. Degradation of (Z)- and (E)-1,3-D was well described by first-o rder kinetics, and rates of degradation for the two isomers were similar. C omposted steer manure (SM) was the most reactive of the organic amendments tested. The half-life of both the (Z)- and (E)-isomers in unamended soil at 20 degreesC was 6.3 days; those in 5% SM-amended soil were 1.8 and 1.9 day s, respectively. At 40 degreesC, the half-life of both isomers in 5% SM-ame nded soil was 0.5 day. Activation energy values for amended soil at 2, 5 an d 10% SM were 56.5, 53.4 and 64.5 kJ mol(-1), respectively. At 20 degreesC, the contribution of degradation from biological mechanisms was largest in soil amended with SM, but chemical mechanisms still accounted for more than 58% of the (Z)- and (E)-1,3-D degradation. The effect of temperature and a mendment rate upon degradation should be considered when describing the fat e and transport of 1,3-D isomers in soil. Use of organic soil amendments ap pears to be a promising method to enhance fumigant degradation and reduce v olatile emissions. Published in 2001 for SCI by John Wiley & Sons, Ltd.