By: Dr. Braulio Jimenez-Velez
Coal ash is a by-product from burning coal used for electricity. It can release 100 times more radiation into the surrounding environment than nuclear material producing the same amount of energy. In addition, it can also carry other inorganic contaminants. During the process of burning coal to create electricity, the incombustible inorganic matter is collected as coal ash, which consists of two major fractions: fly ash and bottom ash. Coal fly ash, accounts for about 78% of the 100 million tons of coal ash generated annually in the United States. The concentrations of metals and other minerals that remain in the ash can increase up to four or five times by volume. Elements such as arsenic, aluminum, lead, mercury, chlorine, selenium, copper, radium, thorium, vanadium and zinc are found in much higher concentrations in the fly ash compared to coal.
Due to the composition of coal ash it is possible that people living nearby may be exposed unexpectedly through one or more exposure pathways, primarily dermal contact, inhalation, or incidental ingestion (water). However, even in these cases, it should not be assumed that exposures to the constituents in coal ash would pose a health risk. US coal power plants produced around 131 million tons of waste in 2008. As of 2000 there were approximately 300 coal combustion waste landfills and 300 surface impoundments used by 440-600 coal fired utilities in the US.
In an incident on December 22, 2008 in Harriman, Tennessee, the containment pond at the Tennessee Valley Authority (TVA) Kingston plant collapsed, spilling out more than 4.1 million cubic meters of ash into the surrounding environment. A video made by a local resident provides a good idea on the effects not only on the environment but also the lives of people living in the vicinity of the spill (view video here). Analyses of ash samples revealed that the spilled sludge contained high levels of toxic metals and radioactivity.
In another incident, ash from coal burned at the Guayama power plant, located in the south coast of Puerto Rico, was dumped in the Dominican Republic, onto the beaches of Arroyo Barril and Manzanillo in 2003 and 2004. Authorities granted permission for AES Corporation to generate electricity in Puerto Rico with the condition that the coal ash waste was removed from the island. But instead of disposing it elsewhere in the U.S. in landfills with the proper linings as recommended by the U.S. EPA, the waste was dumped onto the Dominican Republic beaches. This action resulted in two lawsuits filed in U.S. courts, one by the Dominican Government, another by alleged victims. Residents allege in their complaint that AES illegally dumped approximately 100 million pounds of toxic coal ash waste in Arroyo Barril, and approximately 60 million pounds in Manzanillo. The proud residents of these communities are very poor and many have no electricity. They allege that a variety of acute and chronic medical conditions, never before seen in their communities (including birth defects), ensued at both sites after the dumping incident. For more on the Arroyo Barril and Manzanillo residents’ perspective, see the Miami Herald news article and video.
A major concern is the possible exposure to coal ash through inhalation; since these contain fine particulates roughly the same size as bacteria, so small that they can easily travel in air and be inhaled into the deepest regions of the lungs. A 2006 study by National Research Council found that these coal-burning byproducts “often contain a mixture of metals and other constituents in sufficient quantities that they may pose public health and environmental concerns if improperly managed”.
An EPA report measuring the health risks posed by disposal practices at coal ash dumps confirms that pollution from these sites significantly increases both cancer and non-cancer health risks and degrades water quality in groundwater supplies (read here). The report found that unlined coal ash waste ponds pose a cancer risk 900 times above what is defined as 'acceptable.' The report also finds that coal ash disposal sites release toxic chemicals and metals such as arsenic, lead, boron, selenium, cadmium, thallium, and other pollutants at levels that pose risks to human health and the environment.
The cases highlighted in this article are examples of the debate over the possible health effects of coal ash, a byproduct of coal energy production which when processed and recycled is used in many products including cement and fertilizers.