Abiotic loss of chemicals in soil

A laboratory study was conducted to evaluate the abiotic losses of organics in soil. 2,3- and 2,5-dichlorophenol were added to microcosms containing soil treated either by autoclaving or gamma irradiation or incubated under anoxic conditions. Biologically active aerobic microcosms were used as controls. Losses of the compounds were monitored using gas chromatography. Significant losses were observed in both the autoclaved and irradiated soils. Loss rates in the autoclaved soils were lowest; losses were greatest in the biologically active soils. Anoxic conditions slowed but did not stop the losses. Autoclaving and radiation appeared to increase the sorptive capacity of the soil. The study stresses the difficulty of achieving sterile conditions in soils, even when sound sterilization methods are used by competent analysts. Studies that report information about sterile conditions and abiotic losses of chemicals in soils should check for, and not presume, sterility in any tests that are conducted.