Understanding the Ecological Consequences of Ubiquitous Contaminants of Emerging Concern in the Laurentian Great Lakes Watershed: A Continuum of Evidence from the Laboratory to the Environment

Contaminants of emerging concern (CECs) represent a plethora of chemicals only recently recognized as potentially causing harm at environmental concentrations to organisms through diverse modes of action. Studies have confirmed CECs are pervasive in water, sediment, and fish tissues collected from the Great Lakes watershed, corroborating studies from ecosystems worldwide. In some tributaries, CECs exceed water-quality benchmarks or screening values expected to cause adverse effects in fish based on data from single-compound exposures. However, a scarcity of data precludes predictions about the adverse effects of long-term exposures of resident fish to complex mixture of CECs. We combine a literature review with recent case studies to explore evidence for the effects of CECs gathered across the continuum from field studies to controlled laboratory investigations. This information is used to identify obstacles to the development of natural resource management practices. Ranking prominent among these obstacles are the dearth of analytical capabilities, paucity of mixture studies, and complexity of integrating CEC effects with additional stressors. Despite these knowledge gaps, using existing water-quality benchmarks and developing screening values from the literature can provide limited directions in identifying CEC sources in need of mitigation. Natural resource managers are encouraged to review data on CEC presence and sources when assessing conservation efforts in Great Lakes tributaries.