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Discussion Topic 2, Revisions in EPA drinking and groundwater protection standards

2010 July 7

The current primary standard at 40 CFR Part 192 requires restoration of groundwater at mill tailings and extraction sites to either background concentrations or regulatory “Maximum Concentration Limits”, whichever are higher. 

The regulations at 40 CFR Part 192 provide specific maximum concentration limits for specific hazardous constituents that generally correspond to EPA’s Maximum Contaminant Levels (MCLs) which are used for public drinking water supply protection under the Safe Drinking Water Act (40 CFR Parts 141-143).  The current EPA MCLs for silver, lead, uranium and arsenic (metals which are all potentially present in uranium ore zones) have been revised since 40 CFR Part 192 was last updated–

  • Silver– The current EPA standard (0.1 milligrams/liter) is a secondary MCL and is less restrictive than the maximum concentration limit value in 40 CFR Part 192 of 0.05 milligrams/liter.  Ingestion of silver, which is commonly found with uranium, can cause the disease argyria, a permanent blue-gray discoloration of the skin, as well as kidney damage.
  • Lead—The current MCL for lead in 40 CFR Part 141 is 0.015 milligrams/liter is more restrictive than the maximum concentration limit of 0.05 milligrams/liter in 40 CFR Part 192..  The U.S. Food and Drug Administration requires bottled water for human consumption to meet an even more restrictive standard of 0.005 milligrams/liter or less. Lead is a neurotoxin which can also affect the functioning of the brain and many body organs.
  • Uranium—The current MCL for uranium in 40 CFR Part 141 is 0.30 milligrams/liter. The maximum concentration limit in 40 CFR Part 192 is a concentration of 30 pCi/liter of uranium-234 and uranium-238 combined (equivalent to 0.44 milligrams/liter), which is the standard utilized by the NRC in overseeing licensed facilities. Uranium ingestion can cause kidney disease.
  • Arsenic—The MCL for arsenic in 40 CFR Part 141 is 0.05 milligrams/liter, while the maximum concentration limit in 40 CFR Part 192 is 0.01 milligrams/liter.  Arsenic is a poison which can damage the skin and cause cancers in multiple body organs.

The Agency will also be examining how the existing standards may be applied to address surface and groundwater protection for ISL/ISR facilities, heap leach facilities, and co-mineral development operations.

The Department of Energy, as well as the Nuclear Regulatory Commission and its Agreement States may permit restoration of groundwater to higher Alternate Concentration Limits (ACLs) provided that the higher concentrations pose no present or potential hazard to human health or the environment.  More than twenty specific requirements must be satisfied to allow the use of ACLs (40 CFR 192.02( c)(3)(i)(C) and   

40 CFR.32(a)(2)(iv)).

During its review of 40 CFR 192, EPA is considering whether to leave the groundwater standards unchanged or revise them.

We invite you to provide your thoughts on this topic

Editor's Note: The opinions expressed in Greenversations are those of the author. They do not reflect EPA policy, endorsement, or action, and EPA does not verify the accuracy or science of the contents of the blog.

8 Responses leave one →
  1. Laura Cummins permalink
    July 22, 2010

    The current 40 CFR 192 uranium (234 + 238) standard of 30 pCi/L is actually equivalent to 0.044 mg/L (not 0.44), assuming secular equilibrium (which is not always a good assumption).

  2. dave allard permalink
    July 22, 2010

    Check your values for uranium MCL, 40CFR141 limit is 30 micrograms per liter. Your 0.3 mg/L would be 300 ug/L.

  3. Olga Kolotushkina permalink
    July 23, 2010

    I believe that the EPA should revise the existing groundwater standards for uranium. The EPA should consider recent studies on health impacts of uranium, especially on the reproductive system and fetus development. The EPA should also take into consideration that the currently effective MCL of 0.30-0.44mg/litre significantly exceeds the the World Health Organization’s recommended maximum of 0.015 mg/litre. The difference in these values appears to be so significant that it certainly deserves the EPA’s attention.

  4. JM Block permalink
    July 27, 2010

    Where substance can accumulate within organisms (both plant and animal), there should be greater stringency in regulations. Such stringency should apply regardless of whether the organism is human (or if plant, used by humans). As water allows various chemicals to move through the food chain and through every level of the natural environment, toxic materials must be rigidly controlled. Historically, we have been quite cavalier in allowing heavy metals and radioactive substances to enter the natural environment and, hence, the air we breath, water we drink and food we consume. This has increased genetic mutations, cancers, reproductive disorders, and neural developmental disorders in children. The chemical and mining industries will do everything they can to denude regulations. EPA must take a very strong stand on getting toxics out of the environment. Dilution is not the solution to pollution in a finite world. Setting the MCL for uranium at the WHO max of 0.015 mg/litre would be a good start. Similar levels of reduction need to be for all chemicals and radioactive materials, eventually completely phasing out ANY emissions.
    Zero emissions in the the environment is both possible and preferable.

  5. bcourter permalink*
    July 28, 2010

    Thank you for your input ! The text on this discussion has been revised to reflect the correction on numerical units.

  6. bcourter permalink*
    July 28, 2010

    Thank you for your input! The text on this discussion has been revised to reflect the correction on numerical units.

  7. bcourter permalink*
    July 28, 2010

    Thank you for your very useful suggestion. We will take note of this as we continue our review.

  8. bcourter permalink*
    July 29, 2010

    We appreciate your thoughtful input !! As part of our review we will be examining known and potential impacts to humans, biota, and the environment from uranium and thorium extraction facilities. This will include the different pathways of exposure for radionuclides and metals, including air, water, and the food chain. As we mentioned in responding to a previous post, we will be reviewing the concentration limits for uranium and other hazardous substances in water and appreciate receiving your view on this matter.

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