MERCURY EMISSIONS AND OCCUPATIONAL EXPOSURES
By Caroline Ganim for the SafeMinds Environmental Committee
Maybe the sky isn’t actually falling, but the mercury in our atmosphere is a concern for every living thing on our planet. Mercury is a global pollutant and there is no barrier that keeps it from crossing borders or oceans; it can remain suspended in the upper atmosphere long enough to circle the earth. It is a chemical element which cannot be created or destroyed, it can only change forms. Mercury is being discharged at alarming rates from coal-fired power plants, gold mines, cement kilns, incinerators and even crematories along with thousands of smaller sources. In fact, coal–fired power plants are the largest source of anthropogenic mercury air pollution in the United States, emitting about 48 tons annually. Internationally, man-made mercury emissions totaled an estimated 1930 tonnes in 2005 (UNEP).
If we are inclined to accept business as usual, we should also be ready to accept the following EPA estimated annual list of casualties and illnesses due to coal-powered plant emissions, including: 17,000 premature deaths, 120,000 asthma attacks and 850,000 missed days of work due to illness. Texas accounts for well over 15% of nationwide mercury emissions, while Pennsylvania follows at a distant second with 6.4%.
Once released from into the atmosphere, mercury settles in lakes and rivers, where it is methylated by bacteria and moves up the food chain to humans. According to the EPA, roughly half of our nation’s lakes and reservoirs have levels of mercury that exceed safe levels. The U.S. Geological Survey found that 25 percent of fish sampled from U.S. rivers and streams have unsafe levels of mercury. In addition to mercury, coal-fired power plants are emitting many other harmful toxins including: antimony, beryllium, cadmium, cobalt, lead, manganese, nickel, arsenic, chromium, and selenium.
Beyond concerns about thimerosal in vaccines and its potential association with autism, it is also necessary to consider the role that industrial air pollutants may have on the development of the fetus. The California Department of Health Services found that children with Autistic Disorder in the San Francisco Bay Area were 50% more likely to be born in neighborhoods with high amounts of several toxic air pollutants, particularly mercury. These findings suggest that a mother’s exposure to industrial air pollutants while pregnant might increase her child’s risk of autism. The research team was led by Gayle Windham, Ph.D., of California’s Environmental Investigations Branch. The team obtained hazardous air pollutants (HAPs), as well as birth records and census tract data, to examine the association between HAPs levels and autism. HAPs are chemicals (measured by the EPA), found in outdoor air that have been identified as potential carcinogens, neurotoxins or endocrine disruptors. HAPs include metals such as mercury and cadmium, aromatic solvents, and chlorinated solvents such as vinyl chloride. The research showed that metals such as mercury, cadmium, and nickel were among the HAPs most strongly associated with autism. While Dr. Windham’s study cannot be used to show a conclusive causal linkage between autism and environmental pollutants such as heavy metals, its findings are suggestive and require further study.
A second study, conducted by Raymond F. Palmer, at the University of Texas Health Science Center, San Antonio Department of Family and Community Medicine, found that there was a significant rate of increases in special education and autism rates associated with increases in environmentally released mercury. The study reviewed data from 1184 school districts within 254 counties in the state. Data regarding environmentally released mercury for each county were obtained from the U.S. Environmental Protection Agency Toxic Release Inventory (TRI). Using this data the total number of pounds of environmentally released data was obtained for each county. The study reported that on average, for every 1000 pounds of environmentally-released mercury, there was a 43% increase in special education services and a 61% increase in the rate of autism. Like the Windham Study, these findings suggest the need for further research regarding the association between environmentally-released mercury and developmental disorders such as autism.
Currently there are no national limits set on the amount of mercury being released from power plants. The 1990 Clean Air Act Amendments mandated the EPA to control toxic air pollutants more than 20 years ago. Eleven years ago, the EPA announced it would set such limits for power plants. Finally, on March 16, 2011, the EPA proposed standards to limit mercury, acid gases and other toxic pollution from power plants. The EPA has stated that once the standards are fully implemented, they will prevent 91% of the mercury in coal from being released into the air. EPA estimates that the value of the improvements to health alone will total $59 Billion to $140 Billion in 2016. This means that for every dollar spent to reduce pollution from power plants we will get $5 to $13 in health benefits. The proposed regulations are expected to become a final ruling by November 16, 2011 and the EPA is currently collecting public comments on this issue. The proposed rule allows facilities up to four years, to meet the new standards. Unfortunately, in the interim, the health of many will continue to be compromised by the emissions of coal-fired plants that have not yet installed the technology required to reduce mercury emissions.
The EPA estimates that cement kilns pump roughly 18,000 pounds of mercury into the air annually. The mercury comes from coal used to fire the kilns, as well as the limestone used as raw material. The amount of mercury in both coal and limestone varies widely depending on the site. According to the non-profit law firm Earthjustice, “Some cement kilns emit nearly one and a half times more mercury than the most polluting coal-fired power plants. But because there are fewer kilns, they account for lower levels of atmospheric mercury overall than coal plants.” The EPA, as of August 2010, is acting to control these emissions from Portland cement manufacturing for the first time. Portland cement is the most common type of cement in use across the country. It is used in concrete, mortar, stucco and most non-specialty grout. By the year 2013, when the restrictions are fully implemented, the EPA projects a 92 percent decrease in annual mercury emissions from cement plants.
Another industry that contributes significantly to mercury emissions is gold mining. The rapidly rising value of this precious metal has driven greatly increased production, particularly in the third world. The health of both miners and those who live in the vicinity of a mine can be impacted. According to the EPA, in the United States, 11.5 tons of mercury is emitted each year from gold mining. Fourteen of our nation’s 20 or so gold mines are located in Nevada. These mines are located in an area where gold ore also contains mercury. When the ore is heated, during the gold extraction process, mercury is released into the air. Air emissions from these mines, can travel great distances, affecting states throughout the Intermountain West. Although long overdue, on December 17, 2010, the EPA announced a new Federal Rule which will cut emissions of mercury from the nation’s gold mines. The rule is expected to cut mercury emissions by 77 percent (compared to the 2007 levels). This is the first national standard for mercury emissions from gold mines. It will also impact the industry’s mines in other states such as Alaska, California, Colorado, Montana, South Dakota and Washington.
Mercury exposure from dental amalgams has been previously covered in an article in this series, but it is worth reiterating that mercury amalgams both contaminate water supplies in wastewater from dental offices and provide the primary mercury source in crematory emissions. In 1972, the rate of cremations was less than 5% for all deaths. According to the Cremation Association of North America, the percentage increased rapidly to almost 32% in 2005 and is expected to increase to nearly 46% by the year 2025. While estimates vary significantly, the amount of mercury emitted into the air, per cremation, tends to average between 2 to 4 grams. Some mercury may also collect on the walls of the oven and chimney. Soil samples have shown that while there may often be an elevation of mercury levels in the top soil near crematoria, most (over 99%) is added to the general atmosphere.
Obviously, occupational exposure continues to be a serious threat to many people who work in industries that use mercury. Some of the occupations in which exposure has been documented include mining, smelting, precious metal extraction by amalgamation, instrument and fluorescent bulb manufacture, manufacture of drug and health products containing mercury, felting of fur and dental work. The current Occupational Safety and Health Administration (OSHA) permissible exposure limit (PEL) for mercury vapor is 0.1 milligram per cubic meter of air as a ceiling limit. A worker's exposure to mercury vapor should at no time exceed this ceiling level.
For further information, visit the OSHA website here.
In a world where mercury is in our air, accumulating on our land and contaminating our water, what can you do? In lieu of hiding under a rock, you can consider choose a residence and occupation which are “less likely” to expose you to mercury emissions, and be mindful of what you choose to eat and what products you use. Yet, given the apparent vulnerability of all human beings to mercury toxicity, transitioning to a low-mercury world must be our ultimate goal.
TAKE ACTION
- Let your Congressmen and Senators know that you support legislation to limit mercury emissions from all sources. Although the EPA has made some significant strides in the goal to reduce industrial mercury emissions (for details visit http://www.epa.gov/mercury/), there are powerful industries at work against federal regulations.
- If you are working in an occupation which exposes you to mercury and are experiencing symptoms of illness, consider having a doctor with expertise in heavy metal toxicity testing and treatment evaluate you.
- Contact your local electricity provider to see if green power is an alternative in your area. If it is, you might choose to get your energy from a less mercury-polluting source such as wind, solar, or hydroelectric power.
- Before purchasing jewelry, you might choose to do business with retailers who have pledged to use only responsibly mined gold (for details visit http://www.nodirtygold.org ). Another option, which is both dollar-wise and environmentally friendly, would be to buy antique or estate jewelry.
ADDITIONAL RESOURCES
For additional reading and details of “The Windham Study” click here.
For additional reading and details of “The Palmer Study” click here.