Madison residents are no strangers to mercury contamination in fish, a result of the high mercury levels present in Lake Monona. However, the global extent of mercury pollution is less widely-advertised. In August, the International Conference on Mercury as a Global Pollutant met at the Monona Terrace and ratified a declaration claiming that reducing mercury use and emissions are necessary steps to lowering the health risks associated with the element and its compounds.
""The declaration summarizes what we know about mercury in the environment, from a wide array of expertise,"" said David Krabbenhoft, a research scientist at the U.S. Geological Survey and a conference co-chair.
Mercury is an environmental pollutant that has been released in increasing amounts by manufacturers ever since the Industrial Revolution. High levels of mercury exposure in humans have been shown to have a variety of toxic effects, many of which stem from mercury's ability to inhibit enzymes from breaking down other toxins. From damaging developing fetuses to increasing the risk of cardiovascular disease, mercury's toxic effects are felt throughout one's lifetime.
The conference did not dwell purely upon the human health risk, however. The declaration covered four major topics, including sources of mercury in the atmosphere, risk to humans, fish and wildlife, recovery of mercury-contaminated fisheries and socioeconomic impacts of mercury use and pollution.
Currently much of the mercury pollution comes from industrial mining operations worldwide, especially those mining gold and other precious metals. Miners release mercury compounds into the air as a byproduct of modern extraction techniques, and can accumulate toxic levels of some compounds in their body, contaminating their homes and communities.
""About 10 to 15 million miners are using about a thousand tons of mercury a year to extract gold, exposing themselves and the families to elevated concentrations of mercury vapor and contributing to about ten percent of the human load of mercury to the global environment,"" said Edward Swain, a conference co-chair and research scientist at the Minnesota Pollution Control Agency.
Other major sources of mercury pollution include coal-fired power plants and volcanic eruptions. Mercury also leaks slowly from many kinds of thermometers and fluorescent lamps.
""It is clear that [long-term] mercury use and environmental releases of mercury have had significant social and economic cost,"" Swain said.
As mercury is released into the surrounding environment, it travels up the food chain. Soil absorbs mercury compounds, which are drawn into plants through their roots. Animals consume these plants and slowly develop dangerous concentrations of mercury throughout their lives. Fish can also develop high concentrations of mercury simply by absorbing the chemical while swimming in mercury-heavy waters.
High levels of mercury, if present in food animals, are easily passed to humans. Humans also absorb mercury from the surrounding atmosphere through the skin.
Mercury usage and pollution is heavily linked to the economic and political fabric of our world. Within the last 30 years, mercury emissions have increased in developing nations, counteracting the progress made in decreasing mercury emissions in developed states. Developed nations often have regulatory power over the production standards, while developing nations have much lower emissions standards in order to maintain production in a harsh economic climate.
Mercury, however, does not discriminate based upon socioeconomic status. Like any other global environmental hazard, mercury affects everyone.
