Mercury: the New Lead?

Author:  Toovey Leia
Institution:  Physical Geography
Date:  April 2005

Some scientists are coining mercury to be "The New Lead". Humans are exposed to mercury by one of two ways: as methyl mercury from fish consumption, or by breathing vaporous mercury. Out of these two, methyl mercury is the most deadly; it has the capability of affecting the central nervous system.

Currently, most of the focus of mercury toxicity is on fetuses, which are exposed to the deadly methyl mercury while in a mother's womb. The EPA and FDA are aware of this hazard, and recommend that women of childbearing years limit their intake of fish to 12 ounces a week to protect themselves from the long-term effects of bioaccumulation. However, many scientists are now suggesting that this limit be seriously examined.

Mercury does not just affect unborn babies. Many adults can suffer from hair loss, headaches, and difficulty in concentrating. Studies have also shown that low doses of mercury can have harmful cardiovascular effects on healthy adult men.

A case example of mercury contamination is Laura Pugliese. Laura is a 28-year-old woman who adheres to an extremely healthy lifestyle. She teaches yoga, uses organic shampoos and lotions, and eats an extremely healthy diet. When trying to get pregnant, she visited the doctor to have her mercury levels tested. To her surprise she found that her body had mercury levels 50 percent higher than the EPA's safety level. "I was trying to be healthy and stay away from pesticides and hormones" says Pugliese, who blames her elevated mercury level on her high fish low meat diet, "But instead, I got mercury, not a good tradeoff."

Scientists are just beginning to realize the seriousness that mercury contamination has on society as a whole. Mercury is a pollutant that impairs intelligence and brain functioning in the entire population, and the damage is permanent. It is estimated that one of every 6 babies born in the US is exposed to mercury levels in the womb that are above the current safety guidelines. All of these children are at risk for IQ loss, learning disabilities and other cognitive impairments.

Mercury is present in very low amounts in our environment; however, through the processes of bioaccumulation and biomagnification, it becomes a toxin to higher-level organisms. Bioaccumulation is the process by which organisms can take up contaminants more rapidly than their bodies can eliminate them, thus the amount of the toxin accumulates over time. If an organisms continually intakes a toxin, it can reach deadly levels inside that organism. However, if an organism ceases to ingest a toxin its levels can gradually decline. This is why awareness of the problem is essential. Strict suggestive guidelines will enable individuals to cut back their intake, and hopefully mitigate the problem.

Biomagnification is the incremental increase in concentration of a contaminant at each level of the food chain. This process occurs because the food source for organisms higher on the food chain is progressively more concentrated with contaminants. The exact mechanisms of how mercury initially enters the food chain is still not completely understood. However, at this time it is believed that organisms that process sulfate take up inorganic mercury, and through metabolic processes, convert it to methyl mercury.

The best way to lower our intake of Mercury is to go to the source. Mercury exists naturally in the environment, but its levels have risen up to 500% since industrialization. Coal combustion, chlorine alkali processing, waste incineration, and metal processing are the primary anthropogenic sources. Plans to reduce mercury levels are currently in the works, including President Bush's plans to reduce mercury emission by 70% by 2018.