Permit Issues Forum White Paper

Transcription

1 Permit Issues Forum White Paper Date: Name of Issue: November 9, 2018 Whole Effluent Toxicity Testing Options for Discharges with Unidentifiable Pollutants Summary of Issue/Background: Since the implementation of chronic sublethal Whole Effluent Toxicity (WET) limits began in 2010, numerous dischargers in Colorado have had problems consistently meeting sublethal WET limits for the Ceriodaphnia dubia (C. dubia) species. When this occurs, and toxicity persists through accelerated testing, a Toxicity Identification Evaluation (TIE) must be conducted. When true toxicity has been demonstrated as a failure for both statistical endpoints for reproduction (i.e., IC 25 and NOEC), and the toxicity persists, a TIE is conducted. Ideally a toxicant is identified through the TIE, which allows the discharger to find a solution to remove the toxicant from the effluent. For some dischargers, however, sublethal effects persist and the toxicants are unable to be identified, which may lead to the conclusion of ionic imbalance based on the EPA s TIE methodology. The Colorado Water Quality Control Division s (Division) Implementation of the Narrative Standard for Toxicity In Discharge Permits using Whole Effluent Toxicity (WET) Testing (WET Implementation Policy) states that when a TIE is conducted and the pollutant is unable to be identified or controlled, as is the case of total dissolved solids (TDS)/ionic imbalance, then the permittee must either 1) conduct instream aquatic life investigations or 2) move to a Toxicity Reduction Evaluation (TRE). In the 2010 WET Workgroup process, the Division acknowledged that additional permitting options such as alternate WET species or biomonitoring might be necessary to address discharges with high TDS. Recently, dischargers experiencing ionic imbalance or unidentifiable pollutants have explored the TRE approach, but due to numerous site-specific variables, have been unable to identify a feasible work plan that will conclusively resolve the ionic imbalance or identify a pollutant. Additionally, the data required to conclusively determine that toxicity is either due to ionic imbalance or cannot be identified has not been defined by the Division. Through discussions with the Division, it has also been unclear whether the instream aquatic life approach is truly going to be an acceptable method for addressing discharges that are unable to meet the sublethal WET limit when the pollutant can t be identified, or ionic imbalance is the cause of the failures. When the TRE and instream aquatic life approaches have been exhausted, dischargers are left with no additional avenues for meeting the WET

2 sublethal limits for the C. dubia species because they are unable to identify the toxicants or a control program to eliminate the toxicity. While the acute Daphnia magna (D. magna) method has been approved for use in WET testing since the test was first developed, the only chronic method available to researchers is a 21-day reproduction method, which takes such a large investment of resources that it would be difficult to implement in the NPDES permitting system. The four-day Daphnia magna (D. magna) Survival and Growth method was developed by the U.S. EPA s Office of Research and Development to provide dischargers with a viable method for distinguishing the physical effects that ions cause on C. dubia reproduction from actual toxicity in a faster, more easily implemented method for measuring chronic sublethal toxicity (Lazorchak et. al. 2009). Daphnia magna species using the EPA-approved acute WET method has routinely replaced the C. dubia species in acute WET testing for waters with ionic imbalance or TDS issues as the D. magna species has relatively similar sensitivity to metals and other toxicants as the C. dubia species but is less sensitive to TDS or ionic imbalance. D. magna is currently allowed in Colorado discharge permits with acute WET requirements. The four-day chronic method could provide an additional tool to evaluate the presence of true, sublethal toxicity, particularly when used in conjunction with the chronic C. dubia method. Alternately, or in combination with the D. magna method, the WET Implementation Policy could provide more information about implementing the instream aquatic life approach for dealing with discharges with pollutants that can t be identified, or ionic imbalance. Sponsor/Proponent: GEI Consultants, Inc./Climax Molybdenum Company/Colorado Mining Association Regulations/Guidance Impacted: 1. Policy No. WPC Program Permits 1: Implementation of the Narrative Standard for Toxicity in Discharge Permits Using Whole Effluent Toxicity (WET) Testing (2010) ( WET Testing Policy ). Changes may be proposed to the WET Testing Policy. 2. Regulation 61. Changes to Regulation 61 are not anticipated to arise from the Permit Issues Forum discussion process. Section 61.8(2)(b)(i)(E) requires WET limitations when there is a reasonable potential for the discharge to cause or contribute to an exceedance of a narrative water quality standard. Section 61.8(4)(j) requires all sampling to be performed according to methods specified in 40 C.F.R. Part 136, approved by EPA pursuant to 40 C.F.R. Part 136, or approved by the Division in the absence of methods specific in or approved pursuant to Part 136.

3 3. 40 C.F.R. Part 136. Changes to 40 C.F.R. Part 136 will not be addressed in the Permit Issues Forum process. However, Part 136 is significant because it specifies methods for sublethal WET testing; therefore, alternative methods must be approved in accordance with Part 136. The WET Testing Policy correctly notes that WET testing is not the standard for toxicity, but is an approved 40 C.F.R. Part 136 method. Specifically, the C. dubia reproduction method is one of the EPA-approved biological methods for toxicity listed in 40 C.F.R , Table IA. 40 CFR provides for approval of alternative test procedures for limited use. This procedure includes roles for both the state and the EPA Region. This regulation says that any person can request the Regional Alternative Test Procedure Coordinator to approve the use of alternative test procedure in the Region. Section 136.5(b) says, for an application in a state with an NPDES permit program, the requestor must first submit the application for limited use to the state program Director. The state Director then forwards the request to the Regional ATP (alternative test procedure) coordinator or permitting authority with a recommendation for or against approval. Section 136.5(c) lists the information that must be included with an application for approval of an alternative test procedure for limited use. This information includes the justification for using a different procedure than is specified in the approved methods, a detailed description of the proposed procedure, and comparability data for the performance of the proposed alternate test procedure compared to the performance of the reference method. An alternative test can be approved for use only for a specific discharge or facility (and its laboratory), or to all specified dischargers or facilities specified in the approval. The WET Testing Policy, pg. 8, says that alterations of the testing procedures must go through the Alternative Test Procedure process in 40 C.F.R. Part However, Sections and were revised in 2012, 77 Fed. Reg , (May 18, 2012). As a result, the WET Testing Policy does not include reference to the current procedures for approving alternative test procedures. While a guidance document is in place for alternate test procedures and new method proposals for organic and inorganic analytes, a similar guidance document for WET has been developed, but has not been finalized. While the overall process for approval for all methods has been defined in 40 C.F.R. Part 136, additional details on protocol for approval are included in the Draft Protocol for EPA Approval of New Methods or Alternate Test Procedures for Whole Effluent Toxicity Testing. This document also specifies the differences between limited use and nationwide use, and the differences between an alternative test method and a new method and the WET data requirements for each. Affected Parties: All CDPS permittees with chronic WET limits and discharges with unidentifiable pollutants or ionic imbalance

4 Division Staff: Permits; Enforcement In addition, EPA Regional staff should be included in discussions. This is particularly important for discussion about modifications to the WET Testing Policy to incorporate 40 CFR Part 136 procedures and the ability to approve D. magna tests pursuant to these procedures. Recommended Outcome: Revision of the WET Testing Policy to: Clarify the types of information needed and the currently available EPA and other guidance to be used for determining when a pollutant causing toxicity is not able to be identified. Document the differences between ionic balance interference in WET vs. toxicity from high concentrations of TDS. Clarify the implementation of instream aquatic life investigations as an alternative to meeting WET limitations. Incorporate revisions to 40 CFR Part 136 adopted since 2010 that changed the procedures for approving ATP. This could potentially include specifics in the WET Testing Policy about the state s procedure for approving alternative test procedures for WET. Addition of an option when the pollutant causing toxicity is unable to be identified, consisting of implementation of the Four-Day D. magna Survival and Growth Test method in permits to be used in conjunction with the current chronic C. dubia WET method. Only when the IC 25 and NOEC for C. dubia reproduction and D. magna growth are below the instream waste concentration, will additional testing be required. Division Efficiency Improvement: By providing Permits Section staff with a defined option for addressing dischargers with unidentifiable pollutants and ionic imbalance, less time would be spent dealing with compliance schedules. This would also reduce the time the Enforcement Unit spends evaluating WET failures. Division Business Process Impact: Time would be spent upfront by Permits Section staff, with the assistance of EPA Region 8, to review submitted documentation from the proponents describing how to determine

5 Action List: when a toxicant is unidentifiable, how to implement the instream aquatic life option, and appropriate use of the Four-day D. magna Survival and Growth Method. If the new D. magna method is approved, as well as additional wording added to the WET Policy regarding unidentifiable toxicants and the instream aquatic life option, it would be up to each discharger to present all completed TIE and supporting analysis to demonstrate the toxicant is unable to be identified to be allowed to use the new method. The time spent for Division review would likely be less than the time currently spent evaluating compliance schedule documentation. 1. Proponents to identify available information and recommended guidance for determining when a pollutant causing toxicity is not able to be identified. The outcome of this action item would be language for the WET Policy to clarify the determination of a toxicant that is unable to be identified, and to distinguish between TDS toxicity and ionic imbalance. 2. Proponents to review the implementation of instream aquatic life investigations, including additional definition of the scope and goals of the investigations and potential outcomes. Proposed language for the WET policy will be determined. 3. Proponents to develop proposed language for the WET policy to incorporate the Section process for approvals for limited use, along with a procedure for state review of proposals. Stakeholders, including proponents, the Division, and EPA Region 8, to discuss the availability of the limited use ATP for approval of tests including the use of D. magna. 4. Division staff to support EPA Region 8 in their review all submitted documentation for the D. magna method. Division staff in collaboration with EPA Region 8 staff to evaluate and approve the proposed language for determining unidentifiable toxicants, proposed language regarding instream aquatic life investigations, a proposed process for approval of limiteduse ATPs, and the Four-Day D. magna Survival and Growth method for limited use for dischargers with ionic imbalance or unidentifiable pollutants. 5. The Division would update WPC Program Permits-1, Implementation of the Narrative Standard for Toxicity In Discharge Permits using Whole Effluent Toxicity (WET) Testing to define unidentifiable toxicants, revise references to the ATP approval process, and allow for the use of the chronic D. magna method and/or to provide additional clarification of the implementation of instream aquatic life investigations using proposed terminology. History of Discussion/Actions: In 2006, GEI Consultants, Inc. (GEI) submitted a proposal to use the Hyalella azteca (H. azteca) species as an alternate species for a discharge with high TDS concentrations. In response to the proposal, the Division created a draft entitled, Provisional Protocol for Approval of Alternate Methods in Whole Effluent Toxicity (WET) Testing. While this document was never finalized, additional comments were provided to GEI in a memo from Bob McConnell of the Division dated February 21, 2007 stating,

6 The Division believes that the use of H. azteca in a water-only WET test is an idea worth pursuing. Having the option to use a new test species/method in chronic WET testing would be an important addition to the technical tool kit and potentially offers regulatory flexibility in addressing discharges of high TDS effluents. Flexibility is especially important to dischargers where the costs to remove or reduce TDS is prohibitive. The Technical Memorandum provided considerable information showing the similar sensitivities of H. azteca and Ceriodaphnia dubia to a variety of pollutants. It points out H. azteca s tolerance to the slightly higher TDS conditions that cause toxicity to C. dubia. From the standpoint of similar sensitivities to pollutants and its tolerance to higher TDS effluents, H. azteca would seem to meet the requirements for an alternate species, similar to how Daphnia magna is sometimes used as an alternate species for WET testing in effluent in Colorado with higher TDS concentrations. The memo went on to explain the additional work that would be required to formally propose the H. azteca as a new method. The discharger opted not to move forward with the H. aztecta alternate test species proposal as they were still pursuing alternate treatment options due to other issues with their discharge. Throughout the 2010 WET Workgroup process, the problem of ionic imbalance/tds was discussed. The instream aquatic life component of the WET Implementation Policy was added to address unidentifiable toxicants or TDS/ionic imbalance but it was acknowledged that additional work would need to be done in the future to define an acceptable solution. The idea of an alternate species was also discussed to address the problem. In February 2012, Pioneer/XTO Energy met with CDPHE, EPA Region 8, EPA Headquarters, EPA Office of Research and Development, and USGS regarding the potential approval of the chronic D. magna method for limited use; the method was not approved and alternative methods for compliance with the WET limit were explored. In 2016 Climax Molybdenum Company discussed the possibility of approving the D. magna method for limited use with the Division.