Mobility of chlorofluorocarbons in deposits of shredder wastes from plastic and metal utilizing industries

Chlorofluorocarbons (CFCs) are used as propellants in spray cans, as refrigerants and as blowing agents for plastic foams, which are finally dumped together with solid wastes in landfills. We found shredder waste from plastic and metal utilizing industry to be highly contaminated with F12 (CF₂Cl₂) and less with F11 (CFCl₃). By means of model calculations with one dimensional diffusion models, we were able to estimate the amount and rate of outgassing of CFCs. The models were validated with measured vertical gas concentration profiles. From our results we conclude that deposition of shredder wastes containing CFCs results in a quick loss of these substances to the atmosphere with halflifes of ～ 2 d. In order to reduce CFC emission from landfills, contaminated wastes should be covered with compacted adsorbing layers (e.g., sewage sludge) immediately after their deposition.