Polychlorinated biphenyls, dioxins and furans in ambient air during the Smithville PCB incineration project

The incineration of polychlorinated biphenyl (PCB) wastes is a controversial topic. In this research, the data obtained for almost 1600 ambient air PCB samples and 200 PCDD/DF samples during the course of the Smithville, Canada PCB incineration project, were analyzed to examine the possible contribution of incinerator stack emissions and/or other Site activities on observed levels. A strong seasonal fluctuation in ambient air PCB concentrations was observed. However, testing of the incinerator stack showed that the incinerator emissions were consistently very low and not temperature related. The meteorological and source testing information was used for wind sector analysis, air dispersion and receptor modeling. These results indicated that the Site was the source for the elevated PCB concentrations, but that the incinerator was only responsible for a minor fraction of these concentrations. The primary factor found responsible for the elevated ambient air PCB concentrations was temperature dependent volatilization from on-site storage of high PCB concentration liquids and fugitive emissions from Site activities, such as water treatment.; The results from this research have a number of implications for PCB management policies in particular, as well as air monitoring studies in general. (1) The ongoing storage of PCB contaminated material can result in significant air emissions to the environment. (2) High concentration PCB liquids are more responsible for elevated PCB concentrations and will result in higher concentrations and/or mass emissions of PCB to the environment relative to PCB contaminated soils. (3) Evaluation and selection of remediation technologies must include the environmental effects of ongoing storage and/or the potential problems with alternative technologies. (4) The destruction of the high level PCB liquids resulted in a discernible decrease in ambient air concentrations of PCB. The destruction of all PCB wastes on-site reduced ambient air concentrations to background levels. (5) Wind sector scoring is a practical and easily automated method for looking at possible effects from local sources.