Section 250-RICR-150-05-1.29 - Rhode Island Site Specific Aquatic Life Water Quality Criteria Development ProcedureA. Introduction - There is valid scientific rationale for the contention that the National criteria derived using the November 28, 1980 National guidelines, 45 FR 79341, may be underprotective or overprotective at specific sites. National water quality criteria proposed under Section 304(a) (33 U.S.C. § 1314) or Section 307(a)(1) (33 U.S.C. § 1317) toxic pollutants are based on laboratory toxicity tests in which aquatic organisms were exposed to known concentration of toxicants in laboratory water and, thus, may not adequately represent site water and effluent effects. The underlying intent of adopting water quality criteria into the State's standards is to establish a set of conditions which, if consistently achieved, will not impair the biological integrity of the aquatic community residing in the waterbody.B. A prominent aspect of the National criteria is a provision allowing for modification to reflect local environmental conditions. Incorporating site specific water quality criteria into discharge permits will still ensure that the aquatic community is adequately protected from the effects of toxic pollutant discharges, while considering the mitigation of toxicity due to characteristics of a local waterbody and effluent. The need to reevaluate the National criteria and develop site specific criteria can emerge from many factors including: 1. High natural ambient concentrations relative to standards or criteria.2. The presence of substances for which water quality based effluent limits are below analytical detectability.3. The possibility of complex or synergistic interactions of chemicals within the effluent and/or site water.4. Observed beneficial or detrimental effects on the receiving water biota.C. RIDEM developed this site specific criteria procedure using a Mostly Sanitary Secondary Treatment Plant's (MSSTP) effluent and designated site water in 1990. Due to the uncertainties associated with the instream fate of pollutant loading after discharge, RIDEM will not allow for unchecked or maximum attenuation of toxicity by various physical/chemical parameters in every effluent. Using a MSSTP effluent will afford a consistent, predictable baseline behavior of specific pollutants when attenuated by standard sanitary, secondary effluent components (TSS, alkalinity, pH etc.) This procedure will allow for a moderate amount of attenuation of toxicity by a discharge and site water while addressing the concern of instream fate of pollutant loadings. Site specific criteria may also be developed using the procedures outlined in the EPA document entitled Interim Guidance on Determination and Use of Water-Effect Ratios for Metals (EPA-823-B- 94-001). Since the EPA WER Guidance procedures allow for the evaluation of more site specific characteristics (which may attenuate toxicity) than the RIDEM policy, a more rigorous testing program may be required when following the EPA WER Guidance than that described herein.D. The new criteria developed will be applied only to sites where there are existing discharges and will be administered uniformly to disallow any significant fluctuations in toxicity that may occur due to inconsistencies in the influent component or overall treatment.E. Documentation of the factors that exist at a facility or within a basin, which necessitate site specific criteria development, shall be submitted to RIDEM. This documentation shall include:1. Any previous effluent or instream bioassay test results and/or evaluation of the impact of the discharge on the resident aquatic community.2. Characterization of existing water quality conditions at the site or within the basin.3. The parameters for which site specific criteria are to be developed should be listed with an explanation of why the National criteria for these parameters can not be met.4. An indication of what levels of the parameters of concern could be attained after institution of an aggressive pretreatment program and exploration of other municipal standard treatment controls.F. The municipal effluent and site water data generated from this procedure will be applied to industries as a baseline for permit derivation.G. The criteria developed from one site may be applied to additional sites, if it is demonstrated to the satisfaction of the Director that the hydrologic, ecological and physiographic conditions are consistent between the two sites.H. New permit limits will be developed in accordance with applicable federal and state regulations and laws, including antibacksliding and antidegradation prohibitions.I. Necessary modifications to all permits will be based on compliance bioassay monitoring results.J. Methodology - The RIDEM site specific criteria testing protocol narrowly limits the degree to which mitigation of toxicity may be considered. The RIDEM policy allows that the criteria may be applicable to a number of discharges and site waters. However, the RIDEM protocol is expected to result in more stringent criteria compared to the criteria resulting from following the EPA WER Guidance. EPA's WER Guidance (EPA-823-B- 94-001) should be consulted for further information concerning alternative testing and data analysis procedures. 1. The site specific criteria shall be developed using a Mostly Sanitary Secondary Treatment Plant's (MSSTP, as designated by RIDEM) effluent with site water. This MSSTP will be a standard secondary facility with little or no industrial input. An efficient Wastewater Treatment facility which handles primarily domestic flow will offer the situation of limited buffering of toxicity due to chemicals from industrial inputs and/or domestic organic loadings to the WWTF. This set of tests will represent a best case scenario which can be applied to almost all facilities in the State. Future routine toxicity test results shall be used to monitor continued compliance and may determine if more stringent or lenient permit limits and/or requirements are needed for all facilities.2. The site should be defined on the basis of expected changes in the relevant parameters' biological availability and/or toxicity due to physical and chemical variability of the site water. a. These changes in toxicity cannot result from components present in the effluent of an upstream discharge.b. Due to the complexity of factors, RIDEM will be responsible for delineating sites.c. It is expected that a site and site water will be defined on a basin wide level.3. These bioassay tests shall be conducted in accordance with protocol listed in as specified in § 1.29 of this Part. Additional methods such as protocols listed in 40 C.F.R. § 136, incorporated above in § 1.3(A) of this Part, may be considered at the discretion of the Director a. At a minimum, these tests shall consist of acute toxicity testing of 2 species including a fish (freshwater = fathead minnow, Pimephales promelas; marine = silversides, Menidia spp.) and an invertebrate (freshwater = Ceriodaphnia spp.; marine = shrimp, Mysidopsis bahia).b. Effluent testing shall be conducted on a pre-chlorinated, 24 hour flow proportioned (samples collected hourly), composite effluent sample of the MSSTP. A 100% effluent sample shall be analyzed to determine the concentration(s) of the parameter(s) of concern.4. Acute tests shall be run on the MSSTP effluent diluted with a designated site water (MSSTP mixture) at a ratio of 20 site water:1 effluent, because it represents 75% of the dilution factors established for discharges in Rhode Island. a. The Director may approve a testing protocol which is based upon the actual ratio of effluent and site water which will result under the receiving water design flow specified in § 1.10(C) of this Part. In this case, the site specific criteria will only be applicable to the particular site evaluated.b. An acute screening test shall be conducted on the MSSTP mixture sample, by spiking with one toxicant of concern at concentrations high enough to determine a statistically valid LC50, which is <100%, for that toxicant relevant to each species being tested. Then at least five toxicant concentrations, spaced evenly above and below the previously determined LC50, and a control shall be tested. (1) Two replicates per concentration are required and the number of organisms per replicate will depend on the species being tested.c. In the case of freshwater testing, the hardness of the site water must be monitored at the time the tests are conducted to allow for calculations of the criteria based on hardness.d. Each complete set of tests shall be conducted on three different occasions (dates). (1) Chemical analyses, including hardness, of the site water and MSSTP effluent combined sample will have to be conducted to confirm the concentration of the spiked chemical on selected dilutions during each testing occasion.e. Selected dilutions shall include low, medium, and high concentrations on one replicate and one species. (1) Chemical analyses of these dilutions shall be conducted on a portion of the sample taken immediately prior to the addition of the organisms.f. Dissolved metal analyses must be conducted if the results of the toxicity testing will be used to establish site specific criteria for dissolved metals.g. Similar tests shall be conducted on a control of laboratory water spiked with the toxicant of concern at concentrations not only equivalent to those observed in the effluent, but also which will allow for a statistical comparison with the National criteria.h. Using the data from both sets of replicates, the LC50, standard deviation, and 95% confidence intervals shall be obtained for each species tested in the laboratory water, relative to each toxicant of concern, for each of the three testing occasions. The laboratory water LC50 test results shall be compared to the National acute LC50 values obtained for each testing occasion to confirm the validity of these site specific tests.i. Using the data from both sets of replicates, the LC50, standard deviation, and 95% confidence intervals shall be obtained for each species tested in the MSSTP mixture, relative to each toxicant of concern for each of the valid testing occasions.j. Species-specific water effect ratio shall be calculated for each of the valid testing occasions by dividing the laboratory water LC50 into the MSSTP mixture LC50.k. Two species-specific final WER shall be calculated as the geometric mean of the valid WERs (from each species). (1) These two specific WERs shall be compared to see if they are significantly different (p lt; 0.05). If these two species specific WERs are not different, then the final site specific WER is the geometric mean of these two WERs. If the two species-specific water effect ratios are statistically different, then the WER from the most sensitive species shall be the final site specific WER.l. If the final site specific WER is not significantly different from a value of one (1.0), then the National Acute Criteria is the Site Specific acute criteria. If the final site specific WER is significantly different from a value of one (1.0), then the Site Specific Criteria shall be calculated by multiplying the final site specific WER times the National freshwater acute criteria formula or the National saltwater acute criteria, as appropriate.m. The Director may determine not to use all of the valid testing occasions to calculate the final site specific WER if necessary to protect aquatic life.5. If a National acute/chronic ratio was used to develop the National chronic criteria for the chemical of interest, the site specific chronic criteria is calculated by multiplying the site specific acute criteria by 2 and then dividing by the National acute/chronic ratio.6. If the National acute/chronic ratio for the toxicant of concern does not exist, a site specific chronic criteria can also be obtained by testing species for chronic toxicity. Tests shall be conducted using the same species requirements within §§ 1.29(I)(3)(a) and 1.27(I)(4) of this Part. a. The Director may approve a testing protocol which is based upon the actual ratio of effluent and site water which will result under the receiving water design flow specified in § 1.10(C) of this Part. In this case the site specific criteria will only be applicable to the particular site evaluated.b. The chronic tests shall be conducted in accordance with protocol listed in 40 C.F.R. § 136, incorporated above in § 1.3(A) of this Part, incorporating any deviations from protocol listed below.c. A chronic screening test shall be conducted on the MSSTP and site dilution water mixture by spiking with one toxicant of concern at concentrations high enough to determine a statistically valid chronic toxic effect value for that toxicant relevant to each species being tested. Then at least five toxicant concentrations, spaced evenly above and below the previously determined chronic toxic effect value, and a control, shall be tested.(1) The number of replicates per concentration and the number of organisms per replicate will depend on the species being tested in accordance with the EPA protocol.d. Chronic testing will also follow the requirements listed in §§ 1.29(I)(4)(c) through (e) of this Part.e. Using the data from all sets of replicates, the No Observed Effect Concentration (NOEC), Lowest Observed Effect Concentration (LOEC), and Maximum Acceptable Toxicant Concentration (MATC) for each species tested in the lab water tests, relative to each toxicant of concern, for each of the three testing occasions. The results of the laboratory water test obtained for each testing occasion are compared with the National chronic value to determine the validity of these site specific tests.f. Using the data from all sets of replicates, the No Observed Effect Concentration (NOEC), Lowest Observed Effect Concentration (LOEC), and Maximum Acceptable Toxicant Concentration (MATC) shall be obtained for each species tested in the MSSTP effluent, relative to each toxicant of concern for each of the valid testing occasions.g. Species-specific water effect ratios shall be calculated for each of the valid occasions by dividing the chronic value from the laboratory water test into the chronic value from the MSSTP effluent test.h. Two species-specific final WERs shall be calculated as the geometric mean of the valid WERs (from each species). (1) If the two species-specific WERs are not significantly different (confidence limits overlap), then the final site specific WER is the geometric mean of these two WERs. If the two species-specific final WERs are significantly different from each other, then the WER from the most sensitive species shall be the final site specific WER. i. If the final site specific WER is not significantly different from a value of one (1.0), then the National chronic criteria equals the site specific chronic criteria. If the final site specific WER is significantly different from a value of one (1.0), the site specific Chronic Criteria can be calculated by multiplying the final site specific WER by the National Freshwater Chronic Criteria Formula or the National Saltwater Chronic Criteria, as appropriate.j. The Director may determine not to use all of the valid testing occasions to calculate the final site specific WER if necessary to protect aquatic life.K. Permit Limits and Requirements 1. The information obtained from the three testing occasions will be reviewed by RIDEM to determine the Final Site Specific criteria for each parameter evaluated.2. If the results from these test procedures do not change the National criteria, the National criteria would apply to all dischargers on the waterbody and would be used to derive permit limits where necessary. Chemical specific limits will be developed for those pollutants which would cause an excursion above the National criteria and will be incorporated into permits on a case-by-case basis. a. Dischargers would be required to redesign their facility, if necessary, to ensure compliance with the National criteria and permit limits. Bioassay monitoring requirements and whole effluent toxicity (WET) limits may be developed and incorporate into permits, as necessary, based on previous bioassay test results, continual toxicity during compliance monitoring and new data from dilution studies.3. If the results from these test procedures justify changing the National criterion to a site specific criterion, these new ambient criteria would apply to all dischargers on within the designated site and would be used to derive permit limits.a. For freshwaters, the site specific criteria will be established by multiplying the National criteria, determined at the hardness anticipated during the design receiving water flow, by the final water effect ratio(s).b. These permits may include chemical specific limits and/or whole effluent toxicity limits. Whole effluent toxicity limits and specifics of bioassay monitoring requirements will be based on previous bioassay test results, continual toxicity during compliance monitoring and new data from dilution studies.4. If toxicity testing is incorporated into a permit,a. Facilities with 20:1, or less dilution may be required to conduct chronic toxicity tests.b. Facilities with a 20.1-100:1 dilution may be required to conduct acute tests.c. Facilities with greater than 100:1 dilution may also be required to conduct acute toxicity tests.d. WET limits may be developed based on EPA's acute and/or chronic Toxic Units Method although meeting a minimum LC50 may be required if best professional judgement deems it is necessary.e. Toxicity Identification Evaluations (TIE) and Toxicity Reduction Evaluations (TRE) may be required of any discharger if bioassay compliance monitoring indicates continual toxicity.f. Bioassessment studies may be required to ensure the integrity of the instream aquatic community.250 R.I. Code R. 250-RICR-150-05-1.29
Amended effective 12/28/2023