Mercury Levels High In Wildlife
Not Only Fish Contaminated. Birds, Reptiles and Mammals Affected Too
Variety of species affected show that mercury pollution is widespread. Reproductive and neurological damage seen. Preventing further pollution key to saving wildlife.
High mercury levels have been part of health warnings to limit fish consumption for some time now. But less well known is the damage mercury contamination does to not only to the fish themselves, but to other wildlife as well. Birds, mammals and reptiles are all showing health problems linked to mercury exposure.
Effects of Mercury Contamination
All species of wildlife suffering from mercury toxicity exhibit:
- Reduced reproductive success
- Neurological and physiological damage
- Behavioral abnormalities
In studies of some fish species altered hormone profiles have also been found. Among avian species the common loon has been the worst affected, with some of the highest mercury levels of any animal in the world. Because the loon is long lived (up to 30 years) there are serious concerns for longterm survival of the species because of the reproductive problems. Mercury is highly toxic to developing embryos. Mercury toxicity in the adults results in central nervous system damage affecting vision and muscle coordination. Contaminated birds often fail to nest or lay eggs. Those that do seem unable to brood the eggs or care for hatchlings.
Mercury Contamination in Species that Don't Eat Fish
River otters, mink and raccoon would be expected to suffer from mercury poisoning as fish figure prominently in their diets but a surprise finding has been high levels of mercury in bats in the eastern US. The species of bats involved are insectivores. A Florida panther was found suffering from acute mercury toxicity. It is believed that consumption of contaminated raccoons caused the death of this animal.
Also frightening is that high levels of mercury are being found in forest dwelling songbirds, which feed primarily on invertebrates found among the soil and detritus of the woodland floor. While some of the bird species involved inhabit contaminated watersheds, a few are not associated with feeding along waterways thus implicating airborne mercury as their contamination source.
Among reptiles everything from alligators to frogs have been affected by mercury pollution. In Suriname, rainforest frogs are exposed to mercury from by illegal gold mine discharges.
Sources of Mercury Pollution
Knowing where mercury contamination originates aids in understanding what will be necessary to control its health effects on all living things, including humans. Reducing mercury pollution will be a long slow process involving:
- Developing and supporting clean energy to reduce dependence on coal
- Reducing atmospheric emissions of mercury from power plants and waste incinerators
- Phasing out mercury-containing products and aiding developing countries in obtaining mercury free products
- Promoting safe mercury waste disposal, which includes ensuring that waste mercury from developed nations does not make its way into products in developing countries
Because mercury does not degrade quickly or easily it will be important to make every effort to eliminate mercury pollution. The good news here is that, in areas where mercury contamination has been reduced mercury levels in wildlife drop within a few years.
