5 Colo. Code Regs. § 1002-38.34
The provisions of 25-8-202(1) (a), (b) and (2); 25-8-203; 25-8-204; and 25-8-402 C.R.S. provide the specific statutory authority for adoption of these regulatory amendments. The Commission also adopted, in compliance with 24-4-103(4), C.R.S., the following statement of basis and purpose.
Basis and Purpose:
The adoption of the acute un-ionized ammonia equations as standards for cold water and warm water aquatic life segments which have existing chronic un-ionized standards should provide a more accurate method for protecting these segments from short term water quality impacts due to ammonia. The Commission also believes this is consistent with its approach in other basins of adopting both acute and chronic standards for parameters (e.g. metals) for which acute and chronic criteria have been established in the Basic Standards. It will also bring a consistency to the application of un-ionized ammonia standards in the South Platte Basin itself, where in earlier hearings the Commission established both acute and chronic standards for un-ionized ammonia on six segments.
The designation of the total form of mercury as appropriate for the final residual value (FRV) mercury standards is consistent with a recent change to the Basic Standards. The Commission has determined that total mercury is the appropriate form to be regulated in water bodies where bioaccumulation of methyl-mercury in edible fish tissue could pose a risk to human health. The acute and chronic aquatic life mercury standards will continue to be applied as dissolved mercury on those segments for which site-specific justification was made for their use in lieu of the FRV standard.
The Commission agreed to change the table listing for all coldwater aquatic life segments for the chronic un-ionized ammonia standards listed as NH3 (ch)=TVS to read NH3 (ch)=0.02, for clarification and consistency with the way that the warmwater segments list the un-ionized ammonia standard. There is no change to the numeric standard for any segment with this action.
The Commission has agreed to extend the existing temporary modification for segment 7b of the Upper South Platte Basin, with a new expiration date of April 30, 1994. Martin Marietta Astronautics Group has been approached by the Colorado Department of Parks with a proposal to direct its treated wastewater effluent to a new wetlands to be constructed on Chatfield State Recreation Area property. Martin Marietta Astronautics Group, the Colorado Department of Parks, the Colorado Department of Health and several other organizations and agencies have met regularly over the past year in an effort to determine the feasibility of the project. There are several remaining issues to be addressed and resolved prior to construction. The currently proposed construction schedule for the wetlands does not support the April, 1992 deadline currently dictated by the regulations. The extension of the deadline is required in order to allow the wetlands project to proceed.
New regulations dealing with water quality standards in wetlands are being proposed. These new regulations may have an impact on the participation of Martin Marietta in the wetlands project. Martin Marietta needs additional time to evaluate the proposed new standards for impact to the wetland project.
Martin Marietta has been closely monitoring the sulfate levels in its treated effluent and the levels in the ground water withdrawal point (the five-sided well). Over the course of the monitoring period, sulfate levels in the ground water have remained unchanged, while sulfate levels in the effluent have shown a decrease of approximately 100 mg/l. The continued discharge of sulfate at the current levels is not expected to impact the ground water quality as existing trends have shown.
PARTIES TO THE PROCEEDINGS OF THE PUBLIC RULEMAKING HEARING JANUARY 6, 1992
5 CCR 1002-38.34