Proposed Copper Criteria for Pajarito Plateau Surface Waters

Newport News Nuclear BWXT-Los Alamos; Triad National Security, LLC; and the U.S. Department of Energy, Office of Environmental Management, Los Alamos Field Office (Petitioners) collected surface water quality data to conduct a intensive study of the bioavailability of Copper based on pH, dissolved organic carbon (DOC), and hardness (CaCO₃) on the Pajarito Plateau surrounding Los Alamos National Laboratory. The Petitioners worked with NMED since 2018 to ensure that the study would follow rigorous quality assurance and quality controls and its findings would be suitable for use in a rulemaking process.

The Petitioners prepared a demonstration for a Copper Site-Specific Water Quality Criteria (Cu SSWQC) for the Pajarito Plateau and accepted comments and feedback during a 45-day public comment period. After considering and responding to comments, the petitioners asked the Water Quality Control Commission (WQCC) for a hearing to consider adopting their proposed Cu SSWQC in July of 2024. Initially the hearing was scheduled for October 8, 2024, but was subsequently rescheduled for January 14, 2025.

The hearing was held according to the public notice and members of the public were allowed to participate and offer public comment (in-person and virtually) during the proceeding. At the conclusion of the hearing, the WQCC deliberated and voted to adopt the proposed amendments. The WQCC directed the Petitioners and NMED to finalize language to be submitted to the State Records Center and Archives for inclusion into 20.6.4.900 NMAC. On April 10, 2025, NMED filed a Statement of Reasons, Concise Explanatory Statement, and copy of the adopted rule with SRCA. The amendments were published in the New Mexico Register on April 22, 2025 and will become effective on May 22, 2025.

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