Synopsis: PCBs remain a chemical of concern through out the Great Lakes. Atmospheric deposition from the IADN and other sampling indicates that concentrations in urban areas are greater than in rural areas, which are greater than in remote areas. Monitoring within the Chicago urban area indicates that identifiable source regions exist. Other work has shown that the environment surrounding source regions responds quickly to destruction of PCBs. A number of potential sources have been hypothesized. Since electrical equipment is the largest single use of PCBs and there are indications that, at least under storage conditions, PCB transformers may be responsible, at least in part for these elevated air concentrations. This project is an extension to previous work which conducted preliminary sampling in the vicinity of PCB transformers in order to provide source characterization and emissions estimates. The goal of the project is to: i) produce emissions estimates which can be used to rank the relative importance of transformers relative to other PCB sources; and ii)produce source profiles which might prove useful in identifying potential sources during air monitoring.

Chemicals Studied: Polychlorinated biphenyls were used extensively for numerous purposed between the 1940s and the 1970s, when their production and most uses were banned in North America. Among remaining uses are electrical transformers that were previously in existence and which are operated as “closed systems.” The toxicological effects of PCBs are numerous and well studied. Concentrations found in many sport fish caught in the Great Lakes exceed established risk thresholds for human consumption of these fish. As a result, PCBs are a prevalent cause of fish consumption advisories within the basin.

Geographic Areas: The study is being conducted within the Chicago urban area, with specific focus on several industrial facilities suspected of being significant remaining sources of PCB emissions.

Project Duration: The extended project work began in the Spring of 2005 and will conclude in the Spring of 2007.

Methods Used: Additional targeted sampling and analysis is being in order to address the uncertainties in the data from the previous project. This data is required in order to address limitations in the previous project data and to obtain emissions estimates and source profiles from additional potential sources. In particular, additional stored samples are being obtained through passive sampling, surface wipes and other methods. In addition, preserved samples are being analyzed to expand the data set and for quality control purposes.

Potential Results and Implications: Successful identification of remaining discrete sources of PCBs within the Chicago urban area is the first step needed to successfully eliminate these sources. Monitoring data suggests that the rate of PCB decline in the region’s fish has slowed significantly and nearly stopped. Models suggest that further reductions in the upcoming years will require finding and eliminating continuing sources of these chemicals. Although PCBs are capable of long-range transport, evidence suggests that many remaining sources are within the region, particularly within or near Chicago.

Project Contact:
William Mills , Ph.D.
University of Illinois at Chicago
Phone: (312)413-1085
Email: wmills1@uic.edu