Reducing Mercury exposure from Fish in the Great Lakes Nathan Reynolds Introduction to Nutrition IMPH 2013-2014
Comprised of 5 Lakes Superior, Michigan, Huron, Erie and Ontario • 1/5 of the world’s fresh water • Bound by 8 States and 1 Province • Minnesota, Wisconsin, Illinois, Indiana, Michigan, Ohio Pennsylvania and New York • Ontario Geographical Context
Steam ships started navigating the Great Lakes waterways in 1816 Initially transported timber, fur, grain, meat products, dairy, minerals, copper By the late 19th and 20th century, the Great Lakes region was known as the “Industrial Belt” of America Heavy metal mining, automobile manufacturing, steel smelting and oil refining were integral parts of the economy Utilized steam ships and coal-powered locomotives to carry products to New England Mercury as a waste product History
Mercury Trends in Great Lakes Source: McGoldrick, D., Clark, M., and Murphy, E. 2012. "Contaminants in Whole Fish", In: U.S. EPA and Environment Canada. 2012. State of the Great Lakes 2012
The tendency for the concentration of a substance to increase based on food chain energetics and life longevity of species Predatory Great Lake Fish types • Lake Trout • Brown Trout • Bass • Walleye bioMagnification
High Moderate Average ppm of mercury in popular sport fish Source: University of Toledo. www.eng.utoledo.edu/aprg/courses/dm/risk/tablefigmercpaper.pdf
Once contaminated fish are consumed, methylmercury is readily absorbed. It binds to L-Cysteine, forming a Methylmercury-Cysteine (MeHg-Cys) conjugate, which can easily translocate the Blood-Brain Barrier via amino acid carriers • Accumulation of mercury in neural tissue • Passes through placenta to developing fetus and can cause Cognitive impairment, primitive reflexes and hyperkinesia • Exposure in infants and children can cause Poorer neurological status, impaired development, impaired motor skill development Health Hazards Source: Kerper LE, Ballatori N and Clarkson TW. Methylmercury transport across the blood-brain barrier by an amino acid carrier. Am J Physiol. 1992;262(5 pt2):R761-5. Mergler D, Anderson HA, Chan LHM, Mahaffey KR, Murray M, Sakamoto M and Stern AH. Methylmercury Exposure and Health Effects in Humans: A Worldwide Concern. Royal Swedish Academy of Sciences. 2007; 36(1):3-11.
Distribution of blood THg (μg/L), by reported frequency of fish consumption in 30 days, women aged 16-49 years, NHANES 1999-2010 Risk Group Source: Environmental Protection Agency. Trends in Blood Mercury Concentrations and Fish Consumption Among U.S. Women of Childbearing Age NHANES, 1999-2010. 2013.