Given environmental concerns about contaminants in the Great Lakes, Professor Donald Cole of U of T's Department of Public Health Sciences and colleagues from Health Canada and the Quebec Toxicology Centre conducted studies of both Ontario anglers and sport-fish eaters to ascertain how high their blood mercury levels were in relation to the amount of fish they consumed. Mercury can have an impact on the reproductive function for both men and women and may be toxic to the functioning of a fetus' nervous system.
"Eating fish has well-documented nutritional benefits, such as the cardiovascular protection afforded by its Omega-3 fatty acids," says Cole, the lead researcher for the study, published in the July edition of Environmental Research. "We attempted to collect and analyze data that would assist people in maximizing the benefits of fish consumption while minimizing the health risks."
The researchers targeted those who fished from designated contaminated areas in Mississauga and Cornwall, Ontario and sport-fish eaters from Hamilton, Toronto, Windsor, Niagara and Detroit. The most common fish consumed included bass, yellow perch and walleye.
Their results show that 87 per cent of the anglers had detectable blood mercury levels, all within Health Canada's acceptable range. The consumers all had detectable blood mercury levels, including two with levels above the accepted normal range. However, some had consumption levels that necessitated counselling on exposure reductions strategies.
Researchers also divided sport-fish eaters into two groups: Euro-Canadians and Asian-Canadians. The Asian-Canadians exhibited the highest blood mercury levels, mostly due to their higher overall fish consumption. Euro-Canadians and anglers who consumed sport fish had levels about one-third as high as the Asian-Canadians. Anglers who didn't eat sport fish had the lowest blood mercury levels.
The results illustrate the dilemma of balancing the risks of eating fish with the benefits, says Cole, and emphasize the need for ongoing surveillance of fishing grounds, updated education about contaminant levels and personal awareness of the number of fish meals consumed. Anyone eating 100 fish meals or more annually should pay careful attention to the type and source of the fish they choose.
This research was supported by Health Canada's Great Lakes Health Effects Program and by a Tri-Council Eco-Research Fellowship.
CONTACT:
Donald Cole
Department of Public Health Sciences
416-946-7870
donald.cole@utoronto.ca
or
Elaine Smith
U of T Public Affairs
416-978-5949
elaine.smith@utoronto.ca
Journal
Environmental Research