Paleo-ecotoxicology: What Can Lake Sediments Tell Us About Ecosystem Responses to Arsenic Contamination in Yellowknife (Northwest Territories) Lakes?

Wednesday, October 4, 2017 12:10:00 PM - Wednesday, October 4, 2017 2:00:00 PM
Rm. SS 1069, Sidney Smith Building, 100 St. George Street
Environment Seminar

JENNIFER KOROSI, Assistant Professor, Department of Geography, York University

ABSTRACT: The development of effective risk reduction strategies for aquatic pollutants requires a comprehensive understanding of toxic impacts on biota and communities. Classical toxicological studies conducted in a lab or mesocosm setting are effective for characterizing pollutant impacts on biota in a controlled, simplified environment. Nonetheless, it is well-acknowledged that predictions based on the results of these studies must be tested in a natural ecosystem setting, to account for increased complexity and multiple stressors. Moreover, most ecotoxicological studies are conducted on short timescales (hours to ~1-3 years) due to logistical constraints, but a longer-term perspective is also needed to disentangle complex, nuanced responses of ecosystems to pollutants. Paleolimnology (the study of lake sediment cores to reconstruct environmental change) can address many key knowledge gaps regarding the consequences of pollutant exposure in an environmentally realistic, multi-stressor context. In this presentation, I will explore how paleolimnological approaches can be integrated with more traditional methods of inquiry in ecotoxicology, using legacy impacts of historic gold mining activities in Yellowknife (Northwest Territories) as a case study. Giant Mine, operational between 1948 and 2004, released an estimated 20 million kilograms of toxic arsenic trioxide dust during its lifetime, and arsenic concentrations in Yellowknife lakes remain well above water quality guidelines. Limited water quality monitoring occurred in the region while the mine was operational, and lake sediment cores provide a historic archive that is invaluable for understanding the magnitude of ecological impact resulting from chronic arsenic exposure, and the potential for ecosystem recovery.

BRIEF BIO: Jennifer Korosi is a limnologist (limnology = study of inland waters) who studies ecological and biogeochemical change in lake ecosystems, including the impacts of human activities on ecosystem functioning. Central to her research is the use of lake sediment cores to study long-term (decades to millennia) environmental change, in order to put recent observations into context. She works in both temperate and high latitude regions, on diverse water quality issues like urbanization, acidification, permafrost thaw, and mining and oil and gas developments.