The Hazards of Mercury
By: Oliver Truesdale
Mercury is found naturally in air, water, soil, and rocks. When it is released due to natural events such as volcanic action, fire, floods, or even through the release of vapors in hot springs, it will travel up into the clouds where it then falls to earth via rainfall. Once back on the ground it will drain into water sources where it is absorbed by microorganisms and turned into a more lethal form known as methylmercury. This process also occurs through man-made events such as coal burning power plants, hazardous waste incineration, chlorine and cement production, mining, and improper disposal of mercury products.
Coal burning power plants are the largest human-caused source of mercury emissions in the United States. In 1990, the government started to pay attention to mercury pollution by amending the Clean Air Act. Mercury was removed from batteries and paint, and positive strides to cut down on its use in chlorine plants, industrial boilers, and medical waste incinerators helped to lower mercury emissions by more than 45% at that time. Our current administration is aware of the highly negative impact mercury has on the environment. In this regard, the Environmental Protection Agency's administrator, Lisa Jackson, has pledged to curb emissions at power plants and has already proposed new regulations for the cement industry.
Once mercury is converted into methylmercury, the microorganisms containing the substance are eaten by tiny fish such as minnows, and the toxin is then transmitted all along the food chain. Small fish like anchovies and tilapia will understandably have lower mercury levels than larger predatorial fish like king mackerel, swordfish, shark, and tilefish. Shellfish also contains high levels of methylmercury. Tuna that is used for sushi contains three times more mercury than that which is sold as steaks or fillets, with blue fin and big eye tuna containing the most toxins. If you are a sushi lover, you can find lower levels of mercury in trout, salmon, flatfish, scallops, eel, crab, squid, octopus, and sea urchin. It is a good idea to check your local fish advisories http://www.epa.gov/waterscience/fish/states.htm to determine the safety of fish caught in lakes, rivers, and coastal areas around where you live.
As mercury settles into the land and its waterways, it also becomes a risk to other types of wildlife. Certain types of wetlands attract greater mercury buildup if they have a low pH content, such as those in the Northeast and North Central areas of the U.S. Some of the most vulnerable areas are parts of the Everglades, San Francisco Bay, and newly flooded reservoirs, as well as coastal wetlands along the Gulf of Mexico and the Atlantic Ocean.
A study done in Florida's Everglades shows that the behavior of young egrets has been adversely affected, as has that of mallards and other aquatic birds whose protective enzymes are compromised due to mercury exposure. Diving ducks in the San Francisco Bay, herons and egrets around the Carson River in Nevada, and heron embryos along the Mississippi river provide other examples of the toxic effect that methylmercury has on living creatures.
We humans are no exception. Exposure to mercury at high levels can lead to disabilities of the brain, heart, kidneys, lungs, and immune system. Mercury is extremely dangerous for fetuses as it prevents nerve cells in the brain from proper formation, leading to potential trouble with attention span, motor function, language skills, visual and spatial abilities, and verbal memory. Symptoms such as headaches, fatigue, numbness in the hands and feet, lack of concentration, nervous and digestive problems, and kidney damage are other examples of what can occur when too much mercury is present. The FDA and the EPA have posted warnings for pregnant women to avoid eating fish that attract high mercury levels as it is easily passed through the placenta as well as through breast milk.
Another source of mercury poisoning comes from mercury amalgam fillings that were the popular way to fill cavities in teeth in years gone by. Most dentists do not use mercury fillings anymore, but if you still have some in your mouth, they are undoubtedly leaching the metal into your body in small but regular quantities. If you are not chelating your body on a regular basis to get rid of heavy metals, the accumulation can lead to potential health problems. Studies show that mercury absorption through fillings is actually four times higher than that due to eating mercury-laden fish. One study claims that mercury amalgam fillings can cause brain damage in children, along with neurological and gastrointestinal problems. Brushing, chewing, and wearing braces all contribute to releasing mercury from the fillings, with the toxin accumulating in our organs through time. Many dentists advise exchanging your old mercury amalgam fillings for those that contain no toxins. An FDA report concurs that these types of fillings may be harmful.
Workers who are involved with certain types of products that release mercury can also be affected through exposure. Jobs such as the manufacture of electrical equipment like switches, dry cell batteries, and mercury lamps; chemical processing where mercury is used in the production of chlorine, caustic soda, pesticides, and anti-fouling paints; metal processing, manufacture of explosives, and working around waste incinerators and construction sites can contribute to a potential lethal build-up of mercury in the body.
By paying attention to the products we support and buy we send messages to legislators that we do not uphold the presence of unwanted mercury in our lives. Choosing rechargeable, mercury-free batteries and digital or spirit thermometers; buying and eating fish with low mercury content; and proper disposal of mercury waste are some of the steps we can make towards a methylmercury-free environment.
For more information on the subject, you can visit: http://www.usgs.gov/mercury/
Oliver Truesdale is a frequent art critic whose interests also encompass finding ways to improve life through conscious living.
