Simulation and sterilization of a surrogate soil organic matter for the study of the fate of trichloroethylene in soil

The objective of this paper is to present a procedure for the preparation and sterilization of a surrogate soil organic matter (SSOM) to study the chemical and biological interactions that may occur with trichloroethylene (TCE). For this purpose, the SSOM was prepared by composting sphagnum moss, a readily available and rather homogenous material. Both gamma irradiation and autoclaving were compared for their ability to effectively sterilize the SSOM. The efficiency of gamma irradiation, at varying intensities, was compared with that of autoclaving. Irradiation of SSOM at 50 kGy was found to be the most effective method of sterilization tested. Therefore, the effect of 50 kGy gamma irradiation on the surface properties of the SSOM (as evidenced by the cation exchange capacity (CEC), specific surface area (SSA), pH, infrared spectrophotometry (IRS), and TCE sorption isotherms) were compared with the non-sterilized SSOM. Although there were differences in the CEC and SSA for the two materials, the IRS of sterilized and unsterilized SSOM were similar as was sorption of aqueous TCE at initial concentrations of 2 to 130 mg.L-1.