Biomagnification Study

Biomagnification, also known as bioamplification or biological magnification, occurs when the concentration of a substance, such as DDT or mercury, in an organism exceeds the background concentration of the substance in its diet.


"In the environment, particularly lakes, waterways and wetlands, mercury can be converted to a highly toxic, organic compound called methylmercury through biogeochemical interactions. Methylmercury, which is absorbed into the body about six times more easily than inorganic mercury, can migrate through cells which normally form a barrier to toxins. It can cross the blood-brain and placental barriers, allowing it to react directly with brain and fetal cells. Mercury contamination causes a wide range of symptons in organisms, and affects the kidneys and neurological systems in particular. While low levels may not be directly lethal for individual organisms, toxicological effects like impaired reproduction, growth, neuro-development, and learning ability, in addition to behavioral changes, can lead to increases in mortality and the risk of predation for some wildlife."


"Piscivorous (fish eating) predators such as loons, merganser ducks, osprey, eagles, herons, and kingfishers, generally have very high concentrations of mercury. Mercury has been detected in Common Loons from Alaska to Atlantic Canada, and blood concentrations have been correlated with levels in prey fish species. A recent survey of mercury in loons from five regions across the US and Canada has shown that blood mercury concentrations increased from west to east, with the highest levels in southeast Canada. High levels of mercury are suspected to impair the loon's reproductive success as well as cause growth related problems.These problems inevitably lead to an increased death rate and a decreased birth rate, resulting in a reduction in the abundance of natural populations.
In addition, mercury has been found in predatory mammals such as otters from south central Ontario. It is thought that elevated mercury levels in otters may cause early mortality due to toxicity and behavioral changes. While the reproduction and behavior of bird species is generally affected by exposure to methylmercury, mammals most often suffer neurological effects. The severity of the toxic effects will depend on the degree of exposure, and may range from a slight impairment to reproductive failure or death.
In the past, mercury risk reduction strategies focused on restricting human consumption of heavily contaminated fish in order to protect human health. Such a strategy is clearly not adequate for the protection of wildlife. Species such as otter and mink cannot heed warning notices or fish consumption advisories. Since mercury is so widely distributed in the Canadian environment, their risk is real and immediate, especially when effects such as impaired growth and reproduction, neurological damage, kidney damage, and weight loss, which occur at relatively low concentrations, are considered."

Smith, Jerald W. "Mercury In The Food Chain." Enviornment Canada. N.p., Aug.-Sept. 2013. Web. Aug.-Sept. 2013.