The Interactions of Soil-Borne Microorganisms and DCPA

Abstract

Soil samples with and without a past history of dimethyl-2,3,5,6-tetrachloroterephthalate (DCPA) treatment were obtained from New York. A third sample was obtained from a field in Colorado where DCPA had been ineffective as a herbicide. The populations of bacteria and actinomycetes in these soils were determined and the actinomycetes were more prevalent in the samples with previous DCPA treatment than in untreated samples. Subsequent treatment resulted in an increase in actinomycete population and little change in bacterial population. In pure culture and in soils, the addition of DCPA had no adverse effect upon microbial growth, and several microorganisms appeared to utilize the herbicide as a carbon source. Two degradation products were methyl-2,3,5,6-tetrachloroterephthalate and 2,3,5,6-tetrachloroterethalic acid.

Degradation of Benefin and DCPA in Thatch and Soil from a Kentucky Bluegrass (Poa pratensis) Turf

“…Both DCPA and benefin are reported to be rapidly metabolized in soil (6,7,11,13,15). Soil moisture, temperature, and microbial activity have been reponed as factors affecting herbicide degradation rates.…”

Quantitative determination of the acidic metabolites of Dacthal in ground water by strong anion exchange solid-phase extraction

“…In the soil environment, DCPA is hydrolyzed (Figure 1) to give the corresponding mono-(l-methyl-4-carboxyl-2,3,5,6-tetrachloroterephthalate) and diacid (2,3,5,6tetrachloroterephthalate) metabolites (Gershon and Mc-Clure, 1966). The degradation of DCPA to the monoacid is considered a biologically mediated reaction, while the conversion of the monoacid to the diacid metabolite potentially occurs by both biotic and abiotic processes (Hurto and Turgeon, 1979; Tweedy et al, 1968;Ross et al, 1990; Wettasinghe and Tinsley, 1993). While estimates of the half-life of DCPA in soil range from 11 to 295 days depending upon soil conditions, DCPA has been detected in soils up to 12 months after application (Ross et al, 1990;Miller et al, 1978).…”