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