Date of Award
Open Access Master's Thesis
Master of Science in Environmental Engineering (MS)
Administrative Home Department
Department of Civil and Environmental Engineering
Committee Member 1
Fish within the Great Lakes region of North America are an invaluable resource with economic and cultural significance. While these fish are vital, they contain chemical pollutants that are hazardous to human health. One such man-made group of chemicals, polychlorinated biphenyl compounds (PCBs), continue to be a problem long after the ban on production (1979).
The objective of this research thesis was to assess PCB contamination in fish within the Great Lakes Region. This objective was completed by determining the sources of PCB contamination, defining the ecosystem characteristics that significantly affect fish contamination, predicting when it will be safe to consume a desired amount of fish, identifying which water bodies have higher contamination, and determining if PCBs have significantly declined since the early 1990s.
The assessment of inland lake contamination revealed that lakes impacted by point sources of PCBs can de differentiated from lakes whose only source of PCBs is atmospheric. Principal Component Analysis of PCB concentrations in common fish species revealed that lakes impacted by local, point sources of PCBs had congener distributions in fish dominated by heavier congeners. Similar results were obtained for sites in the Great Lakes; PCBs in Lake Superior fish were found to be derived primarily from atmospheric deposition while the lower lakes had significant contributions from local sources.
It was discovered that deeper inland lakes had higher levels of fish contamination based on multiple linear regression analysis where mean depth was the best predictor of total PCB concentration in fish (r2=0.73). The importance of developed watersheds to Great Lakes fish contamination was revealed using the same form of analysis. Lakes with lower primary production tended to have higher PCB contamination.
The use of a lake model to predict dissolved PCB concentrations from atmospheric concentrations and the EPA’s Bioaccumulation and Aquatic System Simulator (BASS) to model food web dynamics predicted that if atmospheric concentrations continue to decline at the same rate, fish in Michigan’s inland lakes will be safe to consume at a rate of 2 meals per day in roughly 20 years. For most sites in the Great Lakes, there has been a significant decline in PCB contamination since the early 1990s. However, the Great Lakes have a higher level of PCB contamination compared to inland Michigan Lakes.
This thesis research provides the public and scientific community an explanation of the trends in PCB contamination in the Great Lakes Region. Safer fish consumption habits according to PCB contamination are now possible without prohibiting the use of this resource. Modeling tools revealed what can be improved upon to adequately predict chemical accumulation in an aquatic ecosystem. The research provides a better and more comprehensive method to assess chemical contamination in fish so that the safety of humans and the environment can be secured for the future.
Sokol, Emily, "An Assessment of Polychlorinated Biphenyl Contamination in Fish from the Inland and Great Lakes of Michigan", Open Access Master's Thesis, Michigan Technological University, 2015.