PARENT SESSION
75 - Pollution of Alpine Environments
8:00 AM to 6:30 PM, Wednesday, 15 May 2002
Exhibition Area

(75-04) Temporal trends of Mercury and Persistent Organic Pollutants in landlocked char from the Canadian Arctic.

Muir, Derek^*,1, Köck, Guenter², Bright, Doug³, Reist, Jim⁴, Backus, Sean¹, Debenedetti, Anna¹, Sardella, Gino¹, Wang, Xioawa¹, ¹ National Water Research Institute, Environment Canada, Burlington, ON, Canada² Institute of Zoology and Limnology, University of Innsbruck, Innsbruck, Austria³ Royal Roads University, Victoria, BC, Canada⁴ Freshwater Institute, Dept of Fisheries and Oceans, Winnipeg, MB, Canada

ABSTRACT- Arctic char (Salvelinus alpinus) are the major species of fish in lakes in the Canadian high Arctic. Landlocked char have been shown to have relatively high levels of mercury and detectable levels of PCBs and other POPs. However, little is known about temporal trends of these contaminants in char or in any freshwater species in the Canadian arctic. The objective of this study was to determine temporal trends of persistent organic pollutants and metals, especially mercury, in landlocked Arctic char in small arctic lakes. We selected lakes in the Qausuittuq (Resolute) area of Nunavut because of their accessibility and the existing knowledge on the fisheries and limnology. Annual (summer) sample collections of arctic char have been made since 1997 and combined with previously analysed samples from the early 1990s insights into temporal trends can begin to be made. In addition to temporal trends, factors influencing contaminant levels in landlocked char such as sampling time, water temperature, fish trophic status, and sediment contamination have also being investigated. Mean mercury concentrations ranged from about 160 to 200 ng/g (wet wt) in char muscle from Resolute Lake in the period 1992-2001. There was no statistically significant decline in mercury concentrations from 1992 to 2001 although mean concentrations in 2000/01 were 20% lower than those from 1997 and 1992. Mean PCB levels in char from Resolute Lake ranged from 97 to 160 ng/g (wet wt) and were higher in 1997 than in 1999 after adjusting for length, but further sampling is needed to confirm if this is a long term trend. Mercury and PCBs were significantly correlated with 15N in char collected in 1997 and 1999. This suggests that biomagnification of mercury and organochlorines is occurring within the char population due to the presence of piscivorous char. The trophic position of individual char must be taken into account in assessing temporal trends.

Key words: arctic char, PCBs, temporal trends, POPs