W. Va. Code R. § 60-3-9

Current through Register Vol. XLI, No. 50, December 13, 2024

Section 60-3-9 - Remediation Standards

This section shall be used for developing risk-based soil and groundwater remedial objectives for site remediation. The purpose of these procedures is to provide for the adequate protection of human health and the environment relative to the current and the reasonably anticipated future uses of the site while incorporating site-related information, to the extent practicable, which may allow for more cost-effective site remediation based on identified site risks.

9.1. Types of Remediation Standards. - Each applicant who responds to the release of a contaminant at a site shall select and attain compliance with one or a combination of the following remediation standards in subdivision 9.1.a and one or a combination of the remediation standards in subdivision 9.1.b. All standards listed in 9.1.a. and 9.1.b. may be selected based on the application of presumptive remedies such as institutional and engineering controls used to limit or eliminate the exposure of potential receptors to Contaminants of Concern:

9.1.a. Human Health:

9.1.a.1. A De Minimis Risk-Based Standard is one in which contaminant levels pose no substantial risks to human health based on any current or reasonably anticipated future land and water use as provided in subsection 9.2 of this rule. If these levels are below natural background, background levels will be considered the de minimis levels;

9.1.a.2. A Uniform Risk-Based Standard is one which uses pre-approved analytical methodologies established by the Secretary to input exposure factors and other site-specific variables to calculate compound-specific remediation levels that will be protective of human health based on any current or reasonably anticipated future land and water use, as provided in subsection 9.3 of this rule. If these levels are below natural or anthropogenic background levels, the background levels will be considered the uniform risk-based levels;

9.1.a.3. A Site-Specific Risk-Based Standard is one which uses a site-specific analysis of present contamination and develops a remedial approach that considers the remedy selection criteria in subdivision 9.8.a of this rule and is protective of human health based upon any current or reasonably anticipated future land and water use; or

9.1.a.4. The applicant may use a combination of the remediation standards to implement a site remediation plan and may choose to use the Site-Specific Risk-Based Standard whether or not the applicant has made efforts to attain the De Minimis or Uniform Risk-Based Standards.

9.1.a.5. In all cases, the presence of free product at a site requires remediation to the maximum extent practical in accordance with the Voluntary Remediation Program Guidance Manual.

9.1.b. Ecological:

9.1.b.1. A De Minimis Ecological Screening Evaluation is an evaluation of the nature and extent of contaminants following the procedures established in the Voluntary Remediation Program Guidance Manual to determine if potential exposure pathways are completed. If contaminants and ecological receptors of concern do not form complete exposure pathways, no significant risk to ecological receptors is assumed.

9.1.b.2. A Uniform Ecological Evaluation is an assessment where contaminant concentrations are compared to benchmark values listed in subsection 8.1.c.2 which reflect no significant risks to ecological receptors of concern when the concentrations are below these benchmarks. If these benchmark values are below natural or anthropogenic background levels, the background levels will be considered the Uniform Ecological Standard. Where an applicant proposes a remediation standard based on other existing standards which exceed the benchmark levels, and the Secretary determines those other existing standards are not protective of ecological receptors of concern, the Secretary may require a site specific ecological risk assessment in order to establish remediation standards.

9.1.b.3. A Site-Specific Ecological Risk-Based Standard which, based on a site-specific analysis of present contamination, develops a remedial approach that considers the remedy criteria in subdivision 9.8.a of this rule and is protective of ecological receptors of concern for the current or reasonably anticipated future land and water use.

9.1.b.4. The applicant may use a combination of the remediation standards to implement a site remediation plan and may propose to use the Site-Specific Risk-Based Standard whether or not the applicant has made efforts to attain the De Minimis Risk-Based Standards.

9.2. Human Health - De Minimis Standard. - The De Minimis Standard establishes contaminant levels that do not present a substantial risk to human health for exposure pathways established in the conceptual site model. The evaluation of exposure pathways in the conceptual site model may consider the presumptive use of institutional and engineering controls to limit or eliminate exposure when implemented. If, on the basis of the site assessment and the evaluation of the applicable exposure pathways, the site meets these human health standards, the applicant shall perform no further remedial action or characterization with respect to human receptors, except implementation of the presumptive institutional and engineering controls considered in the exposure pathway evaluation.

9.2.a. De Minimis Standards for Soils. - The De Minimis Standards for both surface (less than two feet depth) and subsurface (greater than two feet depth) soils shall be the higher numerical value of concentrations set out in paragraphs 9.2.a.1 or 9.2.a.2.

9.2.a.1. Risk-Based Concentrations (RBCs) for Human Health for Residential or Industrial Site Uses that Consider Direct Contact Exposures (ingestion, dermal, and inhalation). - When risk-based concentrations exceed soil saturation concentrations (CSAT), soil saturation concentrations are considered alternatives to RBCs. All RBCs are presented in the De Minimis Standards Table of the Voluntary Remediation Program Guidance Manual.

9.2.a.2. Natural background concentrations for each constituent as determined by sampling and statistical analyses completed using methods provided in the Voluntary Remediation Program Guidance Manual and/or data sources approved by the Secretary.

9.2.a.3. Migration of Soil Contaminants to Groundwater. - Notwithstanding compliance with the De Minimis Standards for Soils, the applicant shall evaluate the potential for the migration of soil contaminants to cause an exceedance of the De Minimis Groundwater Standards as provided in the Voluntary Remediation Guidance Manual and shall implement control(s) as necessary to limit such migration and mitigate potential future impacts to groundwater quality.

9.2.b. De Minimis Standards for Groundwater. - The De Minimis Standards for groundwater shall be determined as follows:

9.2.b.1. Groundwater contaminant concentration limits established in the Legislative Rule entitled "Requirements Governing Groundwater Standards" (47CSR12);

9.2.b.2. For those contaminants where a concentration limit has not been established in 47CSR12, the higher numerical value of the following:

9.2.b.2.A. The Risk-Based Concentrations (RBCs) for human health for residential site uses will be used as presented in the De Minimis Standards Table of the Voluntary Remediation Program Guidance Manual; or

9.2.b.2.B. Natural background levels for each constituent as determined by sampling and statistical analyses completed using methods provided in the Voluntary Remediation Program Guidance Manual and/or data sources approved by the Secretary.

9.2.c. Vapor Inhalation Pathway. - De Minimis Human Health Standards for soil and groundwater do not include health effects and cancer risks associated with the inhalation of vapors originating from these media. Exposures occurring from the inhalation of Contaminants of Concern in vapor originating from these media must be evaluated following procedures outlined in the Voluntary Remediation Program Guidance Manual.

9.2.d. Revisions to the De Minimis Standards. - The Secretary shall review the De Minimis Standards annually and, if necessary, update the De Minimis Standards to reflect current toxicity information, chemical-specific data, and exposure parameters. Additionally, updates to the De Minimis Standards shall occur following significant regulatory changes such as a revised groundwater quality standard or listing of a new hazardous substance in § 104(14) of CERCLA.

9.2.d.1. Calculating the De Minimis Standards

9.2.d.1.A. The U.S. EPA Regional Screening Level (RSL) equations shall be used to calculate the De Minimis Standards. In circumstances when a chemical does not have approved toxicity data, such as lead, other methods approved by U.S. EPA may be used.

9.2.d.1.B. The sources of toxicity information used to calculate the De Minimis Standards shall follow the order of preference listed in paragraph 8.1.c.1 and may also follow the U.S. EPA use of Toxicity Equivalency Factors, Toxic Equivalency Values, surrogate contaminants, or route-to-route extrapolation for applicable contaminants. However, if there is a scientific basis for selecting a toxicity value different from that selected by U.S. EPA, the Secretary may propose an exception to this protocol and provide detailed justification for the exception through the public comment process outlined in paragraph 9.2.d.2 of this rule.

9.2.d.1.C. Additional chemical-specific data used to calculate the De Minimis Standards shall preferentially come from the Risk Assessment Information System (RAIS), followed by the U.S. EPA CompTox Chemicals Dashboard.

9.2.d.1.D. Exposure parameters used to calculate the De Minimis Standards shall be the most current U.S. EPA Default Exposure Factors. The necessary particulate emission factors, volatilization factors, and soil saturation concentrations shall be calculated using the most current U.S. EPA Soil Screening Guidance. The Secretary may substitute these U.S. EPA default values with more relevant state-specific default values as such data becomes available and provide detailed justification for the exception through the public comment process outlined in paragraph 9.2.d.2 of this rule.

9.2.d.1.E. Prior to public notification of proposed changes to the De Minimis Standards, the calculations of all updates to the De Minimis Standards shall be reviewed and verified for correctness by a third-party environmental risk assessor selected through state purchasing procedures.

9.2.d.2. Public Notification, Public Comment Period, and Implementation

9.2.d.2.A. All proposed changes to the De Minimis Standards shall be promulgated as an interpretive rule pursuant to W. Va. Code § 29A-3-1, et seq., and published in the State Register. For each standard being proposed for update or addition, the following information shall be provided: contaminant name; CAS Registry Number; rationale for updating or adding the contaminant, including changes in the values and sources of toxicity data, chemical-specific data, and exposure factors; media type; current standard; proposed standard; and, if applicable, detailed justification for any exceptions to protocol for calculating the De Minimis Standards, as outlined in paragraph 9.2.d.1 of this rule.

9.2.d.2.B. Upon completion of the annual interpretive rule process, the Secretary shall issue an Order that establishes the De Minimis Standards, whereupon a 30-day public comment period shall commence on the day of publication in the State Register. The Secretary shall review and consider all comments received within the 30-day public comment period. Each person submitting a comment shall receive a direct written response, and all comments and responses shall be compiled and posted on the agency's website.

9.2.d.2.C. Upon review and consideration of all comments received within the 30-day public comment period, the Secretary shall publish the final De Minimis Standards for implementation on the agency's website and incorporate the updated standards into the De Minimis Standards Table in the Voluntary Remediation Program Guidance Manual.

9.2.d.3. Appeals

9.2.d.3.A. Any person who provides a comment during the public comment period and disagrees with the final determination of the De Minimis Standards established by the Secretary's Order may file an appeal with the Environmental Quality Board in accordance with W. Va. Code § 22B-1-7.

9.3. Human Health - Uniform Risk-Based Standard. - This standard sets forth uniform, approved methodologies, exposure factors, and other input variables needed to calculate site risks for residential or nonresidential land uses. The Secretary recognizes that there may be instances where the pre-established input variables may not be applicable to a site, and thus will allow for site-specific variables to replace the default variables with adequate technical justification. Typical parameters that may require site-specific input include soil attenuation factors, site-specific hydrogeologic properties, exposure factors based on designated land and water uses, and institutional controls used to manage potential exposure to site contamination.

9.3.a. Uniform Risk-Based Standards for Surface Soils/Sediments. - The applicant shall derive surface soil and sediment remediation standards for residential or industrial land uses by applying site-specific information to the equations and constants from the Voluntary Remediation Program Guidance Manual or other equations and constants approved by the Secretary considering reasonably anticipated future land and water use.

9.3.b. Uniform Risk-Based Standards for Subsurface Soils. - The applicant shall derive subsurface soil remediation values based on:

9.3.b.1. Migration potentials;

9.3.b.2. Leaching potentials; and

9.3.b.3. Soil Saturation Concentrations. - The equations and constants described in the Voluntary Remediation Program Guidance Manual or other equations and constants approved by the Secretary.

9.3.c. Uniform Risk-Based Standard for Groundwater. - The applicant shall derive groundwater remediation values based on:

9.3.c.1. The Potential for the Groundwater to Serve as a Source of Drinking Water. - The applicant shall not consider as a current or potential drinking water source either groundwater that has a background total dissolved solids content greater than 2500 milligrams per liter (mg/l), or groundwater that the applicant can demonstrate, to the Secretary's satisfaction, is not being used as a drinking water source, cannot be used for future drinking water sources, and is not hydrologically connected to an aquifer being used for drinking water; and

9.3.c.2. Migration Potentials. - The applicant shall apply the equations and constants described in the Voluntary Remediation Program Guidance Manual or other equations and constants approved by the Secretary.

9.3.d. Uniform Risk-Based Standard for Surface Water. - The applicant shall meet the Surface Water Quality Standards developed in 47CSR2. For those contaminants not listed in the Surface Water Quality Standards, applicant shall derive standards based on potential exposures to surface water.

9.3.e. Uniform Risk-Based Standard for the Vapor Inhalation Pathway. - The applicant shall use the methods outlined in the Voluntary Remediation Program Guidance Manual or other methods approved by the Secretary to establish Uniform Risk-Based Standards that protect current and reasonably anticipated future receptors from the exposure to Contaminants of Concern present in the vapor pathway.

9.3.f. Carcinogens. - For individual known or suspected carcinogens, the applicant shall establish remedial standards derived under subdivisions 9.3.a, 9.3.b, and 9.3.c of this rule at levels which represent an excess upper-bound lifetime risk of between one in ten thousand to one in one million (1x10-4 to 1x10-6). If carcinogenic risk greater than 1x10-6 is considered for development of residential remediation goals or greater than 1 x 10-5, for development of industrial remediation goals, the applicant shall provide public notification as specified in subsection 7.3 of this rule.

9.3.g. Systemic Toxicants. - For individual systemic toxicants, remedial standards derived under subdivisions 9.3.a, 9.3.b, and 9.3.c of this rule shall represent levels to which the human population could be exposed without appreciable risk of deleterious effect, where the hazard quotient shall not exceed 1.

9.3.h. If a contaminant exhibits both carcinogenic and non-carcinogenic effects, then the applicant shall use the more conservative risk-based standard (i.e., the lower of the two values) as the remediation standard.

9.3.i. Cumulative Site Risk. - Cumulative upper-bound estimate of site risk per receptor from exposure to known or suspected carcinogens shall not exceed one in ten thousand (1x10-4). The upper-bound estimate of the hazard index for each receptor shall not exceed one (1) where multiple systemic toxicants affect the same target organ or act by the same method of toxicity, or where it is not determined whether multiple systemic toxicants affect the same organ.

9.3.j. Should the site meet uniform risk-based concentrations for all applicable media and related exposure routes, the applicant shall take no further action with regard to human receptors.

9.4. Human Health - Site-Specific Risk-Based Standard. - The applicant shall determine Site-Specific Risk-Based Standards using one or a combination of a BHHRA as described in subsection 8.4 of this rule or a RRA as described in subsection 8.6 of this rule. In establishing the remediation standard under this section, the applicant shall consider the potential for exposure to site contaminants under current and reasonably anticipated future land and water use and the application of institutional and engineering controls.

9.4.a. Carcinogens. - For individual known or suspected carcinogens, the applicant shall establish remedial standards derived under subsection 9.4 at levels which represent an excess upper-bound lifetime risk of between one in ten thousand to one in one million (1x10-4 to 1x10-6). If the applicant considers carcinogenic risk greater than 1x10-6 for individual carcinogens for development of residential remediation goals, or greater than 1 x 10-5 for development of industrial remediation goals, then the applicant shall provide public notification as specified in subsection 7.3 of this rule.

9.4.b. Systemic Toxicants. - For individual systemic toxicants, remedial standards shall represent levels to which the human population could be exposed without appreciable risk of deleterious effect, where the hazard quotient shall not exceed 1. The upper-bound estimate of the hazard index for each receptor shall also not exceed one (1) where multiple systemic toxicants affect the same target organ or act by the same method of toxicity, or where it is not determined whether multiple systemic toxicants affect the same organ.

9.4.c. If a contaminant exhibits both carcinogenic and non-carcinogenic effects, then the applicant shall use the more protective risk-based standard (i.e., the lower of the two values) as the remediation standard.

9.4.d. If probabilistic risk assessment methods are used in establishing the remedial standards or demonstrating the acceptability of the proposed remedial alternative, exposure levels shall approximate the 90th percentile of the exposure distribution.

9.4.e. Groundwater. - The applicant shall establish remedial standards for groundwater using the following considerations:

9.4.e.1. Potential receptors based on the current and reasonably anticipated future use of groundwater and all potential exposure pathways, including the migration of Contaminants of Concern in vapor;

9.4.e.2. The potential for groundwater to serve as a drinking water source, as defined in paragraph 9.3.c.1 of this rule;

9.4.e.3. Site-specific sources of contaminants;

9.4.e.4. Natural environmental conditions affecting the fate and transport of contaminants, such as natural attenuation processes, as determined by scientific methods set forth in the Department's Voluntary Remediation Program Guidance Manual; and

9.4.e.5. Institutional and engineering controls.

9.4.f. Soil. - The applicant shall establish remedial standards for soil/sediments using the following considerations:

9.4.f.1. Potential receptors based on the current and reasonably anticipated future use of the site and all potential exposure pathways, including the migration of Contaminants of Concern in vapor;

9.4.f.2. Site-specific sources of contaminants;

9.4.f.3. Natural environmental conditions affecting the fate and transport of contaminants, such as natural attenuation processes, as determined by scientific methods set forth in the Department's Voluntary Remediation Program Guidance Manual; and

9.4.f.4. Institutional and engineering controls.

9.4.g. The Secretary shall incorporate the equations and constants for risk-based standards into a guidance document, along with other relevant information for establishing and applying the standards to specific sites. The Secretary shall revise the guidance document from time to time as needed to incorporate scientific advancements and new or alternative risk assessment and methods. The guidance document, any subsequent revisions, and any alternative risk assessment methods proposed by an applicant shall be reviewed by independent scientists recognized as experts in relevant risk assessment disciplines. The Secretary shall incorporate, as appropriate, the comments of scientific reviewers into the guidance document or decisions regarding risk-based standards or methods.

9.5. Ecological - De Minimis Screening Evaluation. - This standard sets forth uniform, pre-approved methodologies, exposure assumptions, and other input variables needed to evaluate whether complete exposure pathways exist for aquatic and terrestrial ecological receptors of concern. The Secretary recognizes that there may be instances where the pre-established input variables may not be applicable to a site, and thus will allow for site-specific variables to indicate whether an ecological risk assessment is needed.

9.5.a. Typical parameters that the applicant shall consider when evaluating whether or not to perform an ecological risk assessment include, but are not limited to, the following:

9.5.a.1. An evaluation of whether a complete exposure pathway exists. If no complete exposure pathway exists because either the contamination is restricted in movement or there are no ecological receptors of concern, then no ecological risk exists (e.g., if the majority of the site is paved with roads and buildings, no pathway exists);

9.5.a.2. Some sites may be screened out and not require evaluation given their size, estimated risk to ecological receptors, or lack of valued ecological receptors, including threatened or endangered species;

9.5.a.3. Consideration of local conditions in order to assess whether a site is degrading an aquatic environment. In cases where the site does not present an ecological risk over and above "local conditions" and further release of contaminants into the aquatic environment has been stopped, there will not be a need for further evaluation;

9.5.a.4. A definition of what level of ecological resource is considered valued (e.g., individual, population, community, or ecosystem); and

9.5.a.5. If for each contaminated media, harm is readily apparent and a condition of significant risk of harm to the site biota and habitats clearly exists, further ecological risk characterization would be redundant and is not required. The applicant can then proceed directly to the remedy evaluation.

9.5.b. The following are conditions which may be considered indicators of the need for an ecological risk assessment:

9.5.b.1. Stressors have migrated off-site and become widely distributed in the environment;

9.5.b.2. Wildlife or ecological resources of concern are exposed or have potential for significant exposure to stressors from a site, either on or off-site;

9.5.b.3. Remediation of stressors at a site has the potential to expose ecological resources of concern to further impacts;

9.5.b.4. A potential exists for indirect or cumulative impacts to ecosystems of concern;

9.5.b.5. Rare or sensitive species of concern are potentially impacted;

9.5.b.6. Adverse ecological effects have been observed in an otherwise high-quality habitat; and

9.5.b.7. Projected land use involves sensitive ecosystems.

9.5.c. Should the ecological screening evaluation indicate no complete exposure pathways or other conditions specified in subdivision

9.5.a. of this rule exist, or the site meets the Ecological De Minimis Screening Evaluation outlined in the Voluntary Remediation Program Guidance Manual, the applicant shall take no further action regarding ecological receptors.

9.6. Ecological - Uniform Ecological Evaluation. - The Uniform Ecological Evaluation establishes benchmark levels that do not present a significant risk to potential ecological receptors. If, during initial screening, the applicant finds the site meets these standards, the applicant shall take no further remedial action or perform further characterization, and the site is eligible for issuance of a Certificate of Completion by the Secretary. If at any time during characterization or remedial action the applicant shows that the site meets the Uniform Ecological Evaluation, the applicant shall take no further action, and the Secretary may issue the Certificate of Completion. If site contaminants exceed benchmark criteria, the applicant may propose remediation goals protective of ecological receptors of concern. If the applicant chooses to remediate to benchmark levels, he or she shall use the following:

9.6.a. Uniform Standards for Soils (0-4 feet) shall be the highest of the following numerical values:

9.6.a.1. Benchmarks for relevant ecological receptors that consider direct contact exposures, as presented in the Voluntary Remediation Program Guidance Manual; or

9.6.a.2. Natural or anthropogenic background levels for each constituent as determined by sampling and statistical analyses completed using methods presented in the Voluntary Remediation Program Guidance Manual and/or data sources approved by the Secretary.

9.6.b. Uniform Standards for Sediments (0-6 inches) shall be the highest of the following numerical values:

9.6.b.1. Benchmarks for relevant ecological receptors that consider direct contact exposures, as presented in the Voluntary Remediation Program Guidance Manual; or

9.6.b.2. Natural or anthropogenic background levels for each constituent as determined by sampling and statistical analyses completed using methods presented in the Voluntary Remediation Program Guidance Manual and/or data sources approved by the Secretary.

9.6.c. Uniform Standards for Surface Water shall be the highest of the following numerical value:

9.6.c.1. Applicable State water quality criteria, as established in the Legislative Rule entitled "Requirements Governing Water Quality Standards" (47CSR2); or

9.6.c.2. For those contaminants where State water quality criteria have not been established, the applicant shall use the following, in order of preference:

9.6.c.2.A. U.S. EPA Region III Biological Technical Assistance Group (BTAG) Freshwater Screening Benchmarks.

9.6.c.2.B. U.S. EPA Region IV Ecological Risk Assessment Supplemental Guidance (ERASG).

9.6.c.2.C. Applicable NOAEL (No Observable Adverse Effect Level), if available, or ten percent (10%) of the LOAEL (Lowest Observable Adverse Effect Level) values, as presented in the Voluntary Remediation Program Guidance Manual, for contaminants that do not have BTAG or ERASG freshwater screening benchmarks; or

9.6.c.2.D. Natural or anthropogenic background levels for each constituent as determined by sampling and statistical analyses completed using methods presented in the Voluntary Remediation Program Guidance Manual or approved by the Secretary.

9.6.d. Uniform Standards for Groundwater. - Where groundwater is expected to impact surface water, the uniform standards for groundwater shall be the highest of the following numerical value:

9.6.d.1. Applicable State water quality criteria, as established in the Legislative Rule entitled "Requirements Governing Water Quality Standards" (47CSR2); or

9.6.d.2. For those contaminants where State water quality criteria have not been established, the applicant shall use the higher of the following:

9.6.d.2.A. Applicable NOAEL (No Observable Adverse Effect Level) if available, or ten percent (10%) of the LOAEL (Lowest Observable Adverse Effect Level) values, as presented in the Voluntary Remediation Program Guidance Manual; or

9.6.d.2.B. Background levels for each constituent as determined by sampling and statistical analyses completed using methods presented in the Voluntary Remediation Program Guidance Manual or approved by the Secretary.

9.7. Ecological - Site-Specific Risk-Based Standard. - The applicant shall develop Site-Specific Risk-Based Standards using the procedures and factors established by this subsection.

9.7.a. In establishing the remediation standard under this subsection, the applicant shall consider the potential for exposure of ecological receptors of concern to site contaminants under current and reasonably anticipated future land and water use and the application of institutional and engineering controls.

9.7.b. For individual toxicants, remedial standards shall represent levels to which sensitive (i.e., threatened or endangered) ecological population(s) could be exposed without appreciable risk of deleterious effect, where the hazard index shall not exceed one. For non-sensitive ecological receptors, the applicant shall use a weight-of-evidence approach to establish acceptable remedial standards.

9.7.c. If the applicant uses probabilistic risk assessment methods in establishing the remedial standards or demonstrating the acceptability of the proposed remedial alternative, exposure levels shall approximate the 90th percentile of the exposure distribution.

9.7.d. The applicant shall establish remedial standards for soil, sediment, surface water, or groundwater using the following considerations:

9.7.d.1. Potential receptors of concern based on the current and reasonably anticipated use of the site;

9.7.d.2. Site-specific sources of contaminants;

9.7.d.3. Natural environmental conditions affecting the fate and transport of contaminants, such as natural attenuation processes, as determined by scientific methods set forth in the Voluntary Remediation Program Guidance Manual; and

9.7.d.4. Institutional and engineering controls.

9.7.e. The Secretary shall incorporate the equations and constants into a guidance document, along with other relevant information for establishing and applying such standards to specific sites. The Secretary shall revise the guidance document from time to time as needed to incorporate scientific advancements and new or alternative risk assessment methods. The guidance document, any subsequent revisions, and any alternative risk assessment methods proposed by an applicant will be reviewed by independent scientists recognized as experts in relevant risk assessment disciplines. The Department shall incorporate, as appropriate, the comments of scientific reviewers into the guidance document.

9.8. Remediation Measures. - The applicant may attain any of the remediation standards through one or more remediation activities that can include treatment, removal, engineering or institutional controls, and natural attenuation including, but not limited to, innovative or other demonstrated measures.

9.8.a. Remedy Evaluation. - In selecting a remedial action from among alternatives that achieve the goal of cost effective protection of human health and the environment, the applicant shall balance the following factors, ensuring that no single factor predominates over the others. The applicant shall select the remedy that protects human health and the environment using the following criteria:

9.8.a.1. The effectiveness of the remedy in protecting human health and the environment;

9.8.a.2. The reliability of the remedial action in achieving the standards over the long term;

9.8.a.3. Short-term risks to the affected community, those engaged in the remedial action effort, and to the environment posed by the implementation of the remedial action; 9.8.a.4. The acceptability of the remedial action to the affected community;

9.8.a.5. The implementability and technical practicability of the remedial action from an engineering perspective;

9.8.a.6. Meets protectiveness goal at lowest cost; and

9.8.a.7. Considers net environmental benefits of the remedial action.

9.9. Natural Attenuation. - The applicant may request that the Secretary approve a remediation plan based upon natural processes of degradation and attenuation of contaminants. A request submitted to the Secretary under this subsection shall include a description of site-specific conditions, including written documentation of projected groundwater use in the contaminated area based on current State or local government planning efforts, the technical basis for the request, and any other information requested by the Secretary to thoroughly evaluate the request. In addition, the person making the request must demonstrate to the satisfaction of the Secretary:

9.9.a. That the contaminant has the capacity to degrade or attenuate under the site-specific conditions;

9.9.b. That the contaminant area, such as a groundwater plume or soil volume, is not increasing in size or, because of natural attenuation processes, that the rate of contaminant degradation is demonstrably more rapid than the rate of contaminant migration, and that all sources of contamination and free product have been controlled or removed where practicable;

9.9.c. That the time and direction of contaminant travel can be predicted with reasonable certainty;

9.9.d. That contaminant migration will not result in any violation of applicable groundwater standards at any existing or reasonably foreseeable receptor;

9.9.e. If the contaminants have migrated or are predicted to migrate onto off-site properties, the owner must demonstrate that:

9.9.e.1. Such properties are served by an existing public water supply system dependent on surface waters or hydraulically isolated groundwater, or

9.9.e.2. The owners of the properties have consented in writing to allow contaminant migration onto their property.

9.9.f. That, if the contaminant plume is expected to intercept surface waters, the groundwater discharge beyond the sediment/water interface will not possess contaminant concentrations that would result in violations of standards for surface waters contained in the Legislative Rule entitled "Requirements Governing Water Quality Standards" (47CSR2), or in the case of contaminants for which a water quality standard has not been developed, will not possess contaminant concentrations in excess of a human health or ecological risk-based standard;

9.9.g. That the person making the request will implement a groundwater monitoring program sufficient to document the degradation and attenuation of contaminants and contaminant by-products within and down-gradient of the plume and to detect contaminants and contaminant by-products prior to their reaching any existing or foreseeable receptor. The applicant may satisfy the requirement for groundwater monitoring upon successful completion of all of the following, as determined by the Secretary:

9.9.g.1. Installation of an adequate number of appropriately located groundwater monitoring wells;

9.9.g.2. Collection of a minimum of eight samples of groundwater monitoring data collected no more frequently than quarterly and with no more than fifty percent collected during the same season for site-related contaminants to demonstrate the site meets conditions as specified in subdivision 9.9.b; and

9.9.g.3. Use of an attenuation model approved by the Secretary and calibrated using the aforementioned data. The model must be capable of reliably estimating the extent of contaminant impacts to groundwater and the time required to achieve the applicable groundwater standard;

9.9.h. That all necessary access agreements needed to monitor groundwater quality pursuant to subdivision 9.9.g of this section have been or can be obtained; and

9.9.i. That the proposed remediation plan would be consistent with all other environmental laws.

W. Va. Code R. § 60-3-9