BIODEGRADATION OF ACRYLONITRILE IN SOIL

The aerobic biodegradation of [C-14] acrylonitrile at concentrations ranging from 10 to 1,000 ppm was examined in a variety of surface soils. At concentrations up to 100 ppm, complete degradation of the compound occurred in <2 d in a Londo soil. Greater than 50% of the radioactivity was recovered as [C-14]carbon dioxide following 6 d of incubation. Because the soil had no known previous exposure to acrylonitrile, dissimilation did not appear to require acclimation of the microorganisms. Transient formation of acrylamide and acrylic acid as intermediates of degradation was also observed. These results appear to be consistent with previously published results of acrylonitrile transformation by axenic microbial cultures. Similar results were obtained in studies conducted with Tappan loam (10, 50, 100 ppm) and sand (10 and 50 ppm). Acclimation of the microorganisms was required before degradation of 100 ppm acrylonitrile in sand. Degradation of higher concentrations (500 and 1,000 ppm in Londo soil) was relatively slow and may be due to inhibitory effects of the parent compound.