The biological detoxication of hormone herbicides in soil

Change in population of 2,4-D degraders in the process of 2,4-D degradation in soils under upland and flooded conditions

“…It is well known that 2,4-0 is degraded after a lag period of about 10 days when it is perfused to the soil (AUDUS 1952(AUDUS , 1960OUAH-YENTUMI and KUWATSUKA 1982). In the soil-incubation experiment carried out in this study the duration of the lag period was approximately similar to that reported in soil-perfusion experiments.…”

Metabolic and cometabolic degradation of herbicides in the fine material of railway ballast

“…The time required for 50% mineralization of MCPA was clearly lowered in soil from plots that were previously treated with MCPA (treatments 1 and 2) compared to previously untreated plots (treatment 0; Figure 4) This was expected since enhanced degradation of MCPA following treatment has been repeatedly observed in soil and on agricultural fields (Audus, 1951;Kirkland and Fryer, 1966;Torstensson et al, 1975;Helweg, 1987;Smith et al, 1989;Smith and Aubin, 1991a). The mineralization of MCPA followed typical growth-linked kinetics, displaying sigmoid-shaped curves of 14 C-CO 2 release, and the differences in times required for mineralization were mainly due to differences in the length of the 'lag phase'.…”

“…Degradation of MCPA usually follows growth-associated kinetics, indicating that MCPA is used as a substrate for microbial growth (Audus, 1951). Hence, the dissipation of MCPA in agricultural soils is often rapid, at least after the first time of its use (Kirkland and Fryer, 1966;Torstensson et al, 1975).…”

Disposition of Orange Herbicide by Incineration. Revised Draft Environmental Statement

“…Once breakdown of the herbicide is initiated and completed, the soil microorganisms retain an enhanced capacity for degradation-of that herbicide. For example, Audus (1960) treated a soil with 100 ppm 2,4-0 and 20 days were required for 80% detoxification, but when the soil was treated again only three days were required for 80% detoxification. Colmer (1953) found that 5,000 ppm 2,4-0 were at first inhibitory to a bacterium, but after subculturing three times the organisms grew rapidly in the 5,000 ppm concentration.…”