5 Colo. Code Regs. § 1002-38.38
The provisions of Colo. Rev. Stat. sections 25-8-202(1)(a), (b) and (2); 25-8-203; 25-8-204; and 25-8-402 (1989 Repel. Vol. 11A & 1992 Supp.) provide the specific statutory authority for adoption of these regulatory amendments. The Commission also adopted, in compliance with Colo. Rev. Stat. section 24-4-103(4) (1988 Repel. Vol. 10A & 1992 Supp.), the following statement of basis and purpose.
BASIS AND PURPOSE
Because of the presence of beryllium at the Rocky Flats Plant, the Commission has determined that a site-specific beryllium standard should be added to Big Dry Creek segments 2 through 5, to further assure protection of the downstream water supplies that rely on Standley Lake and Great Western Reservoir. Adoption of the beryllium standard for segments 2 and 3 (not on the Rocky Flats site) as well as for segments 4 and 5, is consistent with the Commission's approach to the adoption of other numerical standards for these segments.
Subsequent to the last revisions to the South Platte Basin water quality standards, the Commission adopted a drinking water supply table in Table III of the Basic Standards and Methodologies for Surface Water for beryllium, equal to 0.0076 micrograms per liter (ug/l). 5 CCR 1002-8, section 3.1.16 . The 0.0076 ug/l table value was based upon the 1990 IRIS data base cancer risk-based number. However, since the adoption of the Table III value for beryllium, the EPA has reevaluated the data and determined that there is only limited evidence of carcinogenicity via drinking water. Consequently, the EPA has recategorized beryllium as a Category II drinking water contaminant and promulgated a final drinking water rule providing a Maximum Contaminant Level Goal of 4 ug/l. 57 Fed. Reg. 31776, 31778 (July 17, 1992). Based upon the EPA's rationale as described in the federal register, the Commission believes that the 4 ug/l standard will be protective of the beneficial use of drinking water supply and so has adopted it as the water supply standard rather that the Table III value.
Following consideration of adoption of revisions to this regulation in January 1992, it was discovered that "Table 2 - Site-Specific Radionuclide Standards" was inadvertently omitted when the regulation, adopted by the Commission in January 1990, was filed with the Secretary of State, so that it did not appear in the official published version of the regulation. To correct this error, the Commission has readopted Table 2 in this proceeding. No substantive changes to the table have been considered or adopted.
The Commission has revised the organic standards and practical quantitation limits (PQLs) applicable to segments 2, 3, 4 and 5. These are included in a new subsection 3.8.5 as a separate table denoted as Table 1A. This should clarify that the new Table 1A standards are applicable only to segments 2 through 5 of Big Dry Creek and that the presently existing tables in sections 3.8.5 remain applicable to the balance of the South Platte, Laramie, Smoky Hill, and Republican River Basins.
The constituents appearing in Table 1A were chosen from the basin-wide tables in 5 CCR 1002-8, sections 3.8.5 (10-91) and the site-specific Table 1 from 5 CCR 1002-8, section 3.8.5 (3-90). The standards and the PQLs for these constituents are derived from the state-wide tables, if there are state-wide standards and PQLs available. 5 CCR 1002-8, section 3.1.11 (10-91). The state-wide standards are adopted as site-specific standards for the limited constituents because they are based upon more current information than the former site-specific and basin-wide standards.
The state-wide standards for the individual organics composing halomethanes (HM) and polynuclear aromatic hydrocarbons (PAH) are adopted as the site-specific standards rather than the basin-wide standard for the group of HM and the pre-existing site-specific standard for the group of PAH. The basin-wide organic standards are adopted as site-specific standards for the organics for which there are no state-wide standards, except as noted. These include parathion, which is a class C carcinogen, and chloromethyl ether (BIS), which remains in the IRIS database since its adoption as a state-wide standard. The basin-wide standards for monohydric phenol, tetracholroethane and trichloroethylene are not adopted as site-specific standards. Monohydric phenol does not appear in the IRIS database and the other two organics appear to be typographical errors; the actual chemicals regulated by site-specific standards are trichloroethane 1,1,2 and tetrachloroethylene. Finally, the Commission retains the site-specific standards for simazine and atrazine because as stated in a previous statement of basis and purpose, these two herbicides are potential carcinogens, and both have been detected in water samples from Rocky Flats.
In July 1991, the Commission adopted PQLs for the state-wide organic chemical standards for use as compliance thresholds in discharge permits. The PQLs associated with the state-wide standards are applicable to segments 2, 3, 4 and 5 of Big Dry Creek in lieu of the basin-wide detection limits listed in 5 CCR 1002-8, section 3.8.5 . PQLs are detection levels based on the Colorado Department of Health's laboratory's best judgement for Gas Chromatography/Mass Spectrophotometry (GC/MS), except as otherwise noted in the "Basic Standards for Organic Chemicals" table in section 3.1.11 . The underlying numeric standards and not the PQLs should be considered protective of water quality uses in segment 5, because detection levels vary from laboratory to laboratory and decrease as laboratory methods improve.
In the January 1990 Rocky Flats site-specific hearing, the organics table (Table 1) contained a footnote referencing the narrative standards - "free from toxics" - found in the Basic Standards Applicable to Surface Waters of the State, 5 CCR 1002-8, section 3.1.11 . That section provides, in part:
...state surface waters shall be free from substances attributable to human-caused point source or nonpoint source discharge in amounts, concentrations or combinations:
The footnote was inadvertently deleted when Table 1 was revised and reformatted, becoming the "Additional Organics Standards" table in the March 1991 basin-wide hearing. During the January 1990 rulemaking, the Commission interpreted the "free from toxics" narrative standard as zero due to the inability to predict with certainty all the chemicals of potential concern that were not then subject to numeric standards. Since then, the Commission, in the February 1991 site-specific ground water hearing, adopted an alternative approach with respect to constituents for which there are presently no numeric standards. The Commission is adopting that approach, found in 5 CCR 1002-8, section 5 CCR 1002-8, section 3.12.7 , as its interpretation of the surface water "free from toxics" standard in order to maintain consistency in regulation of the site-specific surface and ground waters.
The Commission interprets the surface water "free from toxics" standard found in section 3.1.11 as follows with respect to segments 4 and 5 of Big Dry Creek. Where a toxic substance for which no numerical standard has been established is found in a detectable amount, notification shall be given as soon as possible to the operator of the Rocky Flats Plant; the United States Department of Energy; the United States Environmental Protection Agency; the Water Quality Control Division (which will consult as necessary with other components of the Colorado Department of Health); and the Cities of Arvada, Broomfield, Thornton and Westminster. Those entities will meet and attempt to reach a consensus concerning the appropriate numerical level for that substance. If consensus is achieved, the Division shall establish that number as a numerical protection level. Where consensus cannot be reached, the Division will determine the appropriate numerical protection level.
In setting a numerical protection level, the entities listed above will consider the classified uses of surface water segments 4 and 5 that need to be protected and establish the appropriate corresponding numerical protection levels for specific contaminants, based on those classified uses, as outlined in section 3.1.7 of the "Basic Standards and Methodologies for Surface Water." The entities will take into account reasonably available information.
A determination made by these entities or the Division in accordance with the procedure described above will not be deemed to constitute surface water quality standard-setting and will not be applicable outside segments 4 and 5.
If numerical protection levels are established by agreement of the entities, they will jointly petition the Commission for rulemaking to set a standard at the numerical protection level. If the Division establishes a numerical protection level without agreement of all entities, the Division shall ask the Commission to set a standard consistent with the numerical protection level.
If any interested person disagrees with a determination made by the Division in accordance with the procedure described above, it may petition the Commission to adopt a site-specific standard different from the numerical protection level. Any determination made by the Commission during the hearing process would then become binding on the Division, the Department of Energy, and the operator of the Rocky Flats Plant. At the request of the Department of Energy or the operator of the Rocky Flats Plant or an interested person, the Commission will consider such a hearing to be mandatory and de novo.
The footnote which was deleted from Table 1 when it was reformatted as the "Additional Organics Table" is readopted as footnote 1 of Table 1A.
In the January 1990 hearing, the Commission provided that all water quality standards in segment 5 were subject to the temporary modification of "ambient quality" until February 1993. The Commission is extending this temporary modification, with respect to radionuclides only, until December 31, 1994.
The Commission has scheduled a rulemaking hearing for January 1994 to reconsider the current state-wide water quality standards for radionuclides. Following that hearing, the Commission has scheduled a rulemaking hearing for September 1994 to reconsider the site-specific radionuclides standards adopted for waters in the vicinity of the Rocky Flats Plant. In order to preserve the status quo with respect to radionuclide standards pending the outcome of that hearing, the Commission is extending the temporary modification on segment 5 as it applies to radionuclides until December 31, 1994.
The Commission is granting numeric temporary modifications of water quality standards applicable to segment 5 of Big Dry Creek for nine constituents.
In 1989, the Commission granted a temporary modification of all segment 5 standards of "ambient quality." In doing so, the Commission stated:
It is recognized that Rocky Flats may not be able to meet the standards immediately and that temporary modifications may be necessary. However, insufficient data presently exists upon which to develop a full set of numerical temporary modifications at this time. It is expected that sufficient data should be generated in the next three years to allow time to collect adequate data for DOE to decide whether to seek numeric temporary modifications for particular parameters. 5 CCR 1002-8, section 3.8.30(3).
The threshold for granting a temporary modification of a standard is that the numeric standard is not being met at the present time. 5 CCR 1002-8, section 3.1.7 . The data presented by the DOE and EG&G in this hearing indicate that there were only nine constituents for which the 85th percentile data value exceeded the water quality standards.
The Commission is adopting numeric temporary modifications of standards for nine constituents. The temporary modifications are based upon the 85th percentile of the ambient water quality data collected for carbon tetrachloride, tetrachloroethene, trichloroethylene, copper (total recoverable), iron (total recoverable), lead (total recoverable), zinc (total recoverable), manganese (dissolved) and ammonia (unionized).
The Doe and EG&G requested that the Commission should extend the temporary modification of "ambient quality" to all water quality standards in the segment. In support of their request, the DOE and EG&G argues that: segment 5 is used to collect and isolate water before discharge to downstream water supplies; requiring compliance with water quality standards in segment 5 would not result in additional protection to the public; requiring compliance with water quality standards in segment 5 would result in the construction of costly water treatment projects resulting in diversions of funds from the ongoing environmental cleanup at the plant site; and that ambient quality in segment 5 cannot be quantified because no location in segment 5 is representative of the segment. The Doe and EG&G further argued that narrative temporary modifications have not had an adverse effect on water quality in the last three years.
... that water is not withdrawn directly from Walnut or Woman Creek for water supply purposes. This classification has been added to these segments because of the Commission's policy determination that it is appropriate to establish an extra layer of protection for the major water supplies in Great Western Reservoir and Standley Lake, particularly considering the proximity upstream of a major industrial, complex utilizing nuclear materials. 5 CCR 1002-8, section 3.8.30(2).
No Proposal was presented to the Commission to remove segment 5 from state waters or to remove any of the classified uses from the segment. The Commission's policy determination to protect the water supply classification for the segment remains unchanged.
To be consistent with the regulation of other entities discharging to state waters, the Commission underscores the underlying water quality standards to be protective of water quality and uses in segment 5. The EPA and CDH have requested that the DOE implement interim measures consisting of a water quality plan which minimizes the use of the segment 5 instream ponds for treatment. Furthermore, it is the Commission's belief that water quality and use protection levels should be based upon the water quality standards applicable to that segment and not upon any temporary modifications of the standards. The Commission does not believe that its actions will result in increased regulatory costs in order to comply with discharge permit requirements. Where effluent limits are based upon water quality standards, temporary modifications of water quality standards have been granted where the 85th percentile of data for each constituent exceeds the underlying standard. The temporary modifications granted reflect the standard methodology for characterizing ambient quality, therefore, the Commission does not believe that compliance with the discharge permit requirements should require extra treatment during the life of the temporary modifications. The DOE and EG&G argued that the standard methodology for characterizing ambient quality is not appropriate for segment 5 because they believe that the segment is so heterogenous that there is not uniformity to water quality throughout the segment. However, the Division testified that the 85th percentile methodology was adopted as a replacement for the mean plus standard deviation methodology in recognition of the fact that most stream water quality data is not normally distributed.
The Commission is adopting numeric, rather than narrative, temporary modifications. This is consistent with the general practice of the Commission. Numeric Temporary modifications will provide guidance to the EPA permit writers and will hold the DOE accountable for its discharges to state waters. Numeric temporary modifications should not place an undue burden on the DOE because they are based on the 85th percentile methodology for calculation of ambient quality.
Segment 5 water quality was determined in this hearing as the 85th percentile of the available data for segment 5. See 5 CCR 1002-8, section 3.1.7 . The application of the 85th percentile methodology is consistent with the Commission's actions in setting other temporary modifications throughout the state. Although DOE EG&G argued that the 85th percentile methodology did not result in a meaningful determination of segment 5 water quality, no alternative statistical methodology was proposed.
A "goal qualified" has been added to the classified uses to indicate that the segment 5 waters are not presently fully suitable but are intended to become fully suitable for the classified uses.
As similarly stated in the Statement of Basis and Purpose for the site-specific surface water standards adopted in January 1990, the Commission believes that segment 5 state waters should be returned as soon as possible to a condition that will support a full range of classified uses, including use as drinking water supply. As further stated in the previous Statement of Basis and Purpose, although plans have been made and funds have been spent to divert Walnut Creek and Woman Creek waters around Standley Lake and Great Western Reservoir - what the parties have termed, "Option B" - the water supply classification for these streams is currently appropriate. If in the future, permanent diversion structures are constructed, with an appropriate capacity to assure that Walnut and Woman Creek waters will not enter the two reservoirs, the Commission can reconsider the appropriateness of the water supply classification at that time.
The Commission's actions should not result in regulatory costs greater than those contemplated under the RCRA/CERCLA clean-up process.
PARTIES TO THE RULEMAKING HEARING NOVEMBER, 1992
5 CCR 1002-38.38