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(January 24, 2002, Gazette)

Methyl mercury in fish cause for concern

Dr. Robin AndersonDr. Robin Anderson


For many of Labrador’s Innu population, fresh water fish has long been a dietary staple. However, an increase in methyl mercury levels in some species of fish found in the lakes and reservoirs of traditional fishing grounds could be potentially harmful to the health of those who consume these fish. One cause of the increase of mercury in remote Arctic and Atlantic Canada ecosystems may have resulted from long range airborne transport and deposition of mercury.

“Burning of fossil fuels for long range transport of mercury through the air and deposition is a cause of concern for all northern environments,” said Dr. Robin Anderson, an adjunct professor, Biology, at Memorial and a marine habitat research scientist with the Environmental Science Branch of Fisheries and Oceans. She is one of numerous scientists contributing to the Collaborative Mercury Research Network (COMERN). COMERN is an international group of researchers lead by Dr. Marc Lucotte, Université du Quebec à Montréal, hoping to improve general understanding of mercury in ecosystems and the risks to those who eat fish.

“Cold-fired generating plants in the U.S. and other industrialized countries send toxic chemicals such as mercury into the upper atmosphere and they are then moved towards the poles via winds and atmospheric movement,” explained Dr. Anderson. “The creation of reservoirs can also result in increased mercury levels which then will contaminate the aquatic food chains for certain periods of time. Because mercury is bio-concentrated up the food chain the highest levels are found in the predators at the top of the food chain, such as pike and lake trout at the top.

“One of the objectives of this study is to provide the data that is necessary to back up requests to do something about these emissions. There are ways mitigating these emissions such as better scrubbers, use of cleaner coal, and so forth.”

There seems to be only limited effects of mercury on cold blooded animals (fish) and then at relatively high levels, explained Dr. Anderson, and it tends to have a greater effect on warm blood animals – humans are much more sensitive to lower doses.

“It’s a neurological toxin and therefore can affect humans in a number of ways, the subtlest symptoms tend to be questions of fine motor control, such as inability to thread a needle and intellectual capabilities. The more overt symptoms with serious poisoning are trembling, mental retardation, motor control problems of a general nature and even death,” Dr. Anderson said.

The objective of the study is to determine current mercury levels of freshwater fish in northern Labrador. This data will be compared with previous data to determine if mercury levels are increasing in the fish of this area. A four-year fieldwork program will be carried out by scientists with the aid of Innu co-researchers. Preliminary results of each year’s fieldwork will be reported to local communities, providing an opportunity for local input into the sample sites selection. The final results will be publicized, and presentations made to the Labrador Innu communities of Sheshatshiu and Davis Inlet and to the scientific community.

“The research team has been building a strong partnership with the Innu nation and making sure that all the information is available up front,” said Dr. Anderson.

The COMERN network felt it was important to look simultaneously at environmental health and the impact of these environmental changes on the human health of populations that depend on fish. COMERN researchers will also carry out research on the impact of human health. The network made up of 34 institutions and collaborators was awarded $12.6 million from NSERC in May of 2001 and will be looking at mercury levels in numerous ecosystems across Canada.

Dr. Anderson is quick to point out that this study is not meant to frighten people from eating fish.

“Mercury is a naturally occurring chemical and is found in everything in very low levels,” explained Dr. Anderson. “The only concern is when it gets to be a high level and people focus on eating fish with those high levels. Fish is still a good source of protein and has a balance of amino acids. Its high in Omega 3 fatty acids other beneficial chemicals and low in fat. The message is ‘don’t stop eating fish,’ just adjust your fish preferences if need be.”