5 Colo. Code Regs. § 1002-61.35
On 1988, Section 6.9.7 , Aquatic Life Biomonitoring, was adopted by the Commission to address a new federal focus for the discharge permit program. EPA challenged the validity of the adopted regulation, taking the position that it was inconsistent with the existing federal statute and later that it was inconsistent with the provisions of 40 C.F.R. 122.44(d) which were adopted June 2, 1989.
Though some of EPA's concerns were resolved by a 1991 amendment to the regulations, not all items of concern were eliminated. The continuing disagreement has led to numerous permits being vetoed by EPA, with dual state and federal permits resulting for an increasing number of permittees. To resolve this matter, the permit regulation is being revised to delete Section 6.9.7 and a portion of Section 6.9.2 and add a new Section 6.92(5), which is modeled upon 40 C.F.R. 122.44(d). Additional detail regarding the Division's approach to implementing whole effluent toxicity requirements will be provided in Division policy guidance documents.
The federal regulation is currently the subject of lawsuits that have been filed, challenging certain provisions. If such lawsuits ultimately result in revisions to the current federal regulation, appropriate changes to the state regulation would be considered. In addition, efforts are underway to address whole effluent toxicity testing as part of the Clean Water Act reauthorization process. Any legislative changes may similarly result in the amendment of this regulation.
Several parties to the hearing were concerned as to the applicability of Section 6.9.2 , feeling that it addressed provisions other than whole effluent toxicity. One goal relative to whole effluent toxicity is to identify and control the specific toxicants once whole effluent toxicity is identified. Section 6.9.2 effectively states requirements presently contained in Section 3.1.14 of the Basic Standards, with the added authority to replace a whole effluent toxicity limit for a specific parameter with a specific numeric limit where no water quality control standard for that parameter has been established by the Commission. Paragraph B in turn addresses the situation where the specific toxicant cannot be identified but the fraction, such as non-polar organic compounds, is identified. In lieu of establishing numeric limits for all parameters within this fraction, paragraph B provides authority to identify an indicator parameter within the fraction which if maintained below a set level will assure whole effluent toxicity is adequately controlled.
PARTIES TO THE PROCEEDINGS OF THE PUBLIC RULEMAKING HEARING FEBRUARY 2, 1993
5 CCR 1002-61.35