Tag Archives: fish

Better Mercury Standards? It’s a no brainer.

The EPA Safeguard:

Currently the EPA is considering increasing protections on various air toxics, including mercury. The safeguard proposed will prevent 91% of the mercury in coal from being released into the air. This safeguard has been proposed because of a study conducted by the EPA in 2000 which found that 7% of women of childbearing age are exposed to levels of mercury high enough to hurt the developing fetus. Due to the results of this study the EPA feels that it is necessary to regulate mercury, as well as other air toxics, produced by power plants.

Health Impacts of Mercury:

Mercury has been studied most in young children and pregnant women, where it has been found to lead to neurological problems including verbal, visual, motor, and learning disabilities. If exposed to mercury, women who breast feed may also expose their child. According to the EPA, about 300,000 infants each year have an increased risk of being born with learn disabilities because they were exposed to mercury while in utero. Moreover, in as study contracted by the EPA mercury was found to be associated with cardiovascular problems, namely acute myocardial infarction, through epidemiological evidence as well as other measures.

Mercury Sources:

Humans often ingest mercury from fish. However, one of the largest sources of mercury is coal plants. The mercury in coal is released into the atmosphere when coal is burned, and may then be transported long distances. After this, mercury accumulates in clouds and becomes a part of the water cycle. The process of bioaccumulation begins with tiny aquatic plants and animals that take in mercury from the water. These are then eaten by larger fish, and so on. However, with each step up the food chain, the concentration of mercury increases until it reaches levels that are unsafe for humans.

Mercury emissions in Texas are the highest nationwide and Texas has 5 of the 10 top mercury polluting coal plants. These plants are Martin Lake in Rusk Co., Big Brown in Freestone Co., Monticello in Titus, Limestone in Limestone Co., and H W Pirkey in Harrison Co. 

 Texas Fish:

A study conducted by the Costal Bend Bays & Estuaries Program in 2010 tested levels of mercury, polychlorinated biphenyls (PCBs), polychlorinated dibenzodioxins (PCDDs), and polychlorinated dibenxofurans (PCDFs) in various fish including spotted seatrout, black drum, and redfish. A total of 49 fish were tested and they were found in various bays along the coast ofTexas.

Although smaller fish did not contain high levels of the contaminants, 4 out of the 5 oversized redfish collected in the surf zone contained levels of mercury high enough to be deemed unsafe for consumption by Texas Department of State Health Services. Moreover, the larger the fish, the more mercury that had accumulated. The average age of the redfish in this study was 20 years and these fish have a lifespan of around 50 years. It is expected that if the same conditions are present, these fish will continue to accumulate mercury. Redfish are a popular catch and fishermen sell many pounds of meat from the two oversized redfish they are allowed to keep. Although no conclusions can be made as the study was small, the Coastal Bend Bays & Estuaries program recommends further studies on the levels of contaminants in redfish and the Texas Department of Health Services is reviewing the study to determine if consumer advisories are necessary.

What can I do?

Support the EPA’s efforts to reduce harmful mercury pollution by submitting a comment here.

For more information on the safeguard visit the EPA’s site.

For more information on the health impacts of mercury and the worst mercury emitters check out the EPA’s site and the Environmental Integrity Project report.

For more information on the study conducted on Texas Fish visit this site.


For an article related to this post: http://www.caller.com/news/2011/jun/08/toxins-in-certain-game-fish-could-spark-a-closer/

– Julia Von Alexander , Sierra Club Beyond Coal Intern.