What is the new MCL for uranium established by the final Radionuclides Rule?

• A. 130 pg/L
• B. 160 pg/L
• C. 60 pg/L
• D. 30 pg/L

Answer: (D)

MCLs are enforceable limits on contaminant levels in drinking water, set to protect public health over a lifetime of exposure. The final Radionuclides Rule tightened limits for radionuclides to reduce both radiological and chemical health risks from drinking water. For uranium, the rule establishes a very low concentration limit, reflecting the idea that even small amounts can add up with long-term exposure. The value chosen is 30 picograms per liter, which translates to one of the most stringent limits in the rule. Water systems must monitor for uranium and take action if levels approach or exceed this limit, such as applying treatment to remove uranium or providing an alternative water source. The other numbers don’t match the final established value for uranium under this rule.