Current Research Projects
Past Research Projects
Studying how arsenic and mercury affect ecosystems near Yellowknife gold mines
Gold production at Giant Mine in Yellowknife released arsenic trioxide dust to the surrounding environment for many years. We studied the legacy of that arsenic contamination in lakes near Yellowknife. In particular, we showed that high arsenic releases to Pocket Lake near Giant Mine resulted in dramatic changes to the lake’s ecosystem. A novel aspect of our study was to use dated lake sediment cores to show the timing and magnitude of these changes, enabling us to show that contamination from the mine was responsible for the changes observed on a lake ecosystem. In the process, we began developing the concept of Paleoecotoxicology, the use of natural archives like lake sediments to track historical ecological effects of past contamination events.
Sampling a lake near Yellowknife, NWT, Canada. Photo: Martin Pothier
How can firefighters minimize occupational exposures to combustion products?
It has long been known that firefighters experience higher rates of cancer and other maladies than the general population, and occupational exposure to combustion products and other chemicals in fire smoke is suspected to be the cause. Our research was to better understand the chemical exposures that firefighters experience while on the job. We also examined different decontamination methods to help firefighters reduce their exposures to harmful substances while on the job.
Firefighters tackling a blaze in Ottawa (Photo: Jenifer Keir)
Contaminant and Nutrient Amplification by Migratory Animals (Biovectors)
Industrial contaminants reaching the Arctic can have a significant impact on people and ecosystems. The prevailing view is that long range transport of semivolatile contaminants to the Arctic is primarily conducted by the physical system (e.g. winds, currents). Although this view may be correct in terms of bulk budgets and fluxes, it neglects the potential of animal behaviour to focus contaminants into foodwebs due to their behaviours and lifecycles. In particular, gregarious animals that biomagnify and bioaccumulate certain contaminants and then migrate and congregate can become the predominant pathway for contaminants in many circumstances following five major steps: emissions, loading, collection, transport, and deposition or transfer of contaminants to receptor sites. Anadromous fish, like sockeye salmon, colonial seabirds, and whales provide prominent examples for such behavior in the Arctic. We examined the potential for biovector transport in the Arctic to expose receptor ecosystems to pollutants.
The major processes involved in contaminant amplification from biovector transport.
(From Blais et al. 2007. Environ. Sci. Technol.)
Thaw slump Mackenzie Delta, NT (photo:A. Houben)
Impact of Thawing Permafrost on Biogeochemical Cycles
We assessed the impact of thawing permafrost on freshwaters on the Mackenzie Delta in the Northwest Territories, and in Old Crow Flats in the Yukon. By identifying lakes affected by recent permafrost thaw slumps with aerial photographs, and comparing lakes receiving large discharges from thawing permafrost with lakes where permafrost degradation is less apparent, we determined the extent that melting permafrost affects water quality (organic contaminants, metals, nutrients). Using this information, we can develop methods to track permafrost degradation in lakes. By extracting lake sediment cores, we applied these tools to reconstruct the history of permafrost degradation in lakes, and determine if chemical releases by permafrost thawing diminish over time. Finally, we determined if contaminants released by degrading permafrost are accumulating in freshwater food webs that constitute an important part of traditional diet and lifestyle.
Impact of Climate Warming on the Biogeochemistry of Northern Environments
Recent and dramatic climate changes in Arctic freshwaters are affecting the transport and fate of anthropogenic contaminants to aquatic systems, the two largest threats facing northern communities and ecosystems. This research developed new tools to examine how the fate of anthropogenic contaminants is affected in Arctic regions under different climate change conditions. Due to the paucity of direct environmental monitoring in Arctic regions, this research investigated how contaminant cycles in Arctic freshwater ecosystems are affected by climate change as recorded in sediment archives. We combined established, state-of-the-art technologies in reconstructing climate from preserved sedimentary paleolimnological proxies, and concurrent records of contaminant deposition histories.
An inundated lake near Yellowknife, NT
Photo: L. Kimpe
Waste Treatment Centre, Corunna, ON
Photo: A. Al Ansari
Pharmaceuticals and Personal Care Products in the Environment
Endocrine disrupting chemicals (EDCs) are a class of chemicals that mimic the action of natural hormones in the environment and adversely affect the function of the endocrine system leading to alteration in growth, development, and reproduction in exposed animals. Steroidal estrogens, alkylphenols, certain pesticides, bisphenol A and synthetic musk fragrances are EDCs that are being detected in the effluent of wastewater treatment plants (WWTPs) as well as the receiving waters and sediments at very low concentrations but are sometimes present at biologically active concentrations. In male fish and frogs, the induction of vitellogenin (VTG), a precursor egg yolk protein synthesized typically in females by the action of their endogenous estrogen, and intersex are well recognized biological endpoints of estrogenic chemicals in the environment.
