§ 250.1. Definitions.

 In addition to the words and terms defined in the act, the following words and terms, when used in this chapter, have the following meanings, unless the context clearly indicates otherwise:

   ASTM—The American Society for Testing and Materials.

   Act—The Land Recycling and Environmental Remediation Standards Act (35 P. S. § §  6026.101—6026.909).

   Agricultural purposes—Commercial agricultural activities, including, but not limited to, irrigation of crops, watering of livestock, and food production, processing or packaging.

   Anisotropy—The variability of a physical property based on direction, for example, variation in permeability in relation to direction of groundwater flow.

   Community water system—As defined in the Pennsylvania Safe Drinking Water Act (35 P. S. § §  721.1—721.17), a public water system, which serves at least 15 service connections used by year-round residents or regularly serves at least 25 year-round residents.

   EQL—Estimated quantitation limit.

   Enterprise zone—An area specially designated as an enterprise zone under requirements determined by the Department of Community and Economic Development.

   Environmental protection acts—Includes:

     (i)   The Clean Streams Law (35 P. S. § §  691.1—691.1001).

     (ii)   The Municipal Waste Planning, Recycling and Waste Reduction Act (53 P. S. § §  4001.101—4001.1904).

     (iii)   The Hazardous Sites Cleanup Act (35 P. S. § §  6020.101—6020.1305).

     (iv)   The Low-Level Radioactive Waste Disposal Act (35 P. S. § §  7130.101—7130.906).

     (v)   The act of July 13, 1988 (35 P. S. § §  6019.1—6019.6), known as the Infectious and Chemotherapeutic Waste Disposal Law.

     (vi)   The Air Pollution Control Act (35 P. S. § §  4001—4015).

     (vii)   The Surface Mining Conservation and Reclamation Act (52 P. S. § §  1396.1—1396.31).

     (viii)   The Noncoal Surface Mining Conservation and Reclamation Act (35 P. S. § §  3301—3326).

     (ix)   The Dam Safety and Encroachments Act (32 P. S. § §  693.1—693.27).

     (x)   The Solid Waste Management Act (35 P. S. § §  6018.101—6018.1003).

     (xi)   Other State or Federal statutes relating to environmental protection or the protection of public health.

   Habitats of concern—A habitat defined as one of the following:

     (i)   Typical wetlands with identifiable function and value, except for exceptional value wetlands as defined in §  105.17 (relating to wetlands).

     (ii)   Breeding areas for species of concern.

     (iii)   Migratory stopover areas for species of concern.

     (iv)   Wintering areas for species of concern.

     (v)   Habitat for State endangered plant and animal species.

     (vi)   Federal, State and local parks and wilderness areas, and areas designated as wild, scenic or recreational.

     (vii)   Areas otherwise designated as critical or of concern by the Game Commission, the Fish and Boat Commission or the Department of Conservation and Natural Resources.

   Heterogeneity—Nonhomogeneous structure, composition and physical properties.

   MCL—Maximum contaminant level.

   MSC—Medium-specific concentration.

   NIR—Notice of Intent to Remediate.

   NPDES—National Pollutant Discharge Elimination System.

   PQL—Practical quantitation limit.

   Property—A parcel of land defined by the metes and bounds set forth in the deed for that land.

   Regulated discharge—A point or nonpoint source discharge subject to the permit or approval requirements of Chapters 91—96, 97 (reserved) and 102—105 and any diffuse surface or groundwater discharge to surface waters which has the potential to cause an exceedance of the water quality standards in Chapter 93 (relating to water quality standards).

   Risk assessment—A process to quantify the risk posed by exposure of a human or ecological receptor to regulated substances. The term includes baseline risk assessment, development of site-specific standards and risk assessment of the remedial alternatives.

   SIA—special industrial area—Property where there is no financially viable responsible person to perform remediation or property located within an enterprise zone, and where the property was used for industrial activity.

   Secondary contaminants—A regulated substance for which a secondary MCL exists, and no lifetime health advisory level exists.

   Site—The extent of contamination originating within the property boundaries and all areas in close proximity to the contamination necessary for the implementation of remediation activities to be conducted under the act.

   Species of concern—Species designated as of special concern, rare, endangered, threatened or candidate by the Game Commission, the Fish and Boat Commission or the Department of Conservation and Natural Resources, if the species has not also been designated threatened or endangered by the Federal government.

   TF—Transfer factor.

   Volatile compound—A chemical compound with a boiling point less than 200° centigrade at 1 atmosphere.

 (a)  This chapter provides remediation standards which shall be used whenever site remediation is voluntarily conducted or is required under environmental statutes in section 106 of the act (35 P. S. §  6026.106).

 (b)  A person who is required to perform a site remediation under an enforcement action of the Department shall meet the following:

   (1)  Select one or a combination of the background standards contained in Subchapter B (relating to background standard), Statewide health standards contained in Subchapter C (relating to Statewide health standards) and site-specific standards, contained in Subchapter D (relating to site-specific standards).

   (2)  Demonstrate compliance with the substantive, procedural and notice requirements of the act and this chapter.

 (c)  To qualify for liability protection under the act, a person conducting remediation shall comply with this chapter and the act. Administrative and procedural requirements for remediations in paragraphs (1) and (2) shall be used in lieu of those requirements listed in this chapter to qualify for liability protection under the act.

   (1)  Persons remediating sites placed on the Pennsylvania Priority List shall comply with the Hazardous Sites Cleanup Act (35 P. S. § §  6020.101—6020.1305), except for the cleanup levels which are set by the act.

   (2)  Persons remediating releases from storage tanks regulated under the Storage Tank and Spill Prevention Act (35 P. S. § §  6021.101—6021.2104) shall comply with the requirements of the corrective action process under the Storage Tank and Spill Prevention Act, except for the cleanup levels which are set by the act.

 (a)  Contaminated media removed for reuse, treatment or disposal shall be managed in accordance with the Solid Waste Management Act (35 P. S. § §  6018.101—6018.1003), The Clean Streams Law (35 P. S. § §  691.1—691.1001), the act of July 13, 1988 (P. L. 525, No. 93) (35 P. S. § §  6019.1—6019.6), known as the Infectious and Chemotherapeutic Waste Law, the Air Pollution Control Act (35 P. S. § §  4001—4015) and the regulations thereunder.

 (a)  The PQLs shall be selected from the PQLs specified by the EPA as EQLs in the most current version of the EPA RCRA Manual SW-846 (U. S. EPA, 1990. Test Methods for Evaluating Solid Waste, Physical/Chemical Methods. Third Edition. Office of Solid Waste and Emergency Response) for soil listed as ‘‘low level soil’’ and for groundwater listed as ‘‘groundwater’’ in accordance with the following:

   (1)  For inorganic compounds, the PQLs under this chapter shall be the values listed for methods associated with analysis by Inductively Coupled Plasma (ICP) with the following exceptions:

     (i)   For lead, cadmium, arsenic and selenium, values listed for the atomic absorption graphite furnace methods for water shall be used.

     (ii)   Mercury shall be the value listed for the cold vapor method.

   (2)  For organic compounds, the PQLs shall be the EQLs listed for the GC/Mass spec methods—for example, Method 8240 for volatile organic compounds.

 (b)  If the PQL selected under subsection (a) is higher than the MCL or HAL for an organic regulated substance in groundwater, the PQLs shall be derived from the analytical methodologies published under the drinking water program in the most current version of Methods for the Determination of Organic Compounds in Drinking Water (U. S. EPA, 1988, Environmental Monitoring Systems Laboratory, EPA/600/4-88/039). If a PQL determined under this subsection is not below a HAL, the methodologies in subsection (c)(1) or (2) shall be used unless those quantitation limits are higher than the PQL determined under this subsection.

 (c)  For regulated substances when EQLs set by the EPA have a health risk that is greater (less protective) than the risk levels set in sections 303(c) and 304(b) and (c) of the act (35 P. S. § §  6026.303(c) and 6026.304(b) and (c)) or for substances when no EQL has been established by the EPA, the limits related to the PQL shall be the quantitation limits established by the methodologies in paragraph (1) or (2).

   (1)  A level set by multiplying 3.18 by the published method detection limit (MDL) of the most recently approved EPA methodology.

   (2)  A level representing the lowest calibration point that can consistently be determined to have a percent relative standard deviation (%RSD) of less than 30% or correlation coefficient of greater than 0.995 using reagent water.

 (d)  For regulated substances which have no limits related to PQLs identified in subsection (c)(1) or (2), a person shall demonstrate attainment under the site-specific standard or the background standard.

 (e)  When a minimum threshold MSC is used as a Statewide health standard, the minimum threshold MSC is the Statewide health standard regardless of whether it is higher or lower than a quantitation limit established by this section.

 (f)  Nothing in this section restricts the selection of valid and generally accepted methods to be used to analyze samples of environmental media.

 (a)  Public notice under the background, Statewide health or site-specific standard and under a special industrial area cleanup shall be initiated by the applicant through an NIR. For remediations proposing the use of a site-specific standard or, for remediations under an SIA agreement, the public and the municipality where the site is located shall be provided a 30-day period, in the NIR, in which the municipality may request to be involved in the development of the remediation and reuse plans for the site.

 (b)  The remedial investigation report, the risk assessment report and the cleanup plan, prepared under a site-specific remediation, may not be submitted to the Department until after the initial 30-day public and municipal comment period following the submission of the NIR has expired.

 (c)  The baseline environmental report, prepared under an SIA remediation, shall be submitted after the initial 30-day public and municipal comment period has expired.

 (d)  For areas not covered entirely by a nonuse aquifer areawide certification granted under §  250.303(f) (relating to aquifer determination; current use and currently planned use of aquifer groundwater), at the same time a request for a nonuse aquifer designation under the Statewide health standard is made to the Department, the remediator shall send notice to every municipality and community water supplier servicing the area requested for designation as nonuse under §  250.303(b). The notice shall include a copy of the request for determination of nonuse aquifer submitted to the Department.

 (e)  Upon receipt of notice of a request for a nonuse aquifer designation, the municipality and community water supplier shall have 45 days to indicate to the Department and the remediator any information relevant to the requirements of §  250.303.

 (a)  The publication date of the summary of the NIR in a newspaper of general circulation in the area of the site shall initiate the 30-day public and municipal comment period during which the municipality can request to be involved in the development of the remediation and reuse plans for a site being remediatedto a site-specific standard or for remediation at an SIA.

 (b)  The person proposing remediation shall be responsible for developing and implementing a public involvement plan if both of the following circumstances exist:

   (1)  The remediation involves a site-specific standard or an SIA cleanup.

   (2)  A municipality, through its official representatives, has requested, in writing, to be involved in the development of the remediation and reuse plans within the 30-day public and municipal comment period identified in the notice to the municipality and the newspaper notice.

 (c)  If a public involvement plan has been initiated, the person proposing remediation shall, at a minimum, provide:

   (1)  Public access at convenient locations for document review.

   (2)  Designation of a single contact person to address questions from the community.

   (3)  A location near the remediation site for any public hearings and meetings that may be part of the public involvement plan.

 (d)  If a public involvement plan has been requested, it shall be submitted with one of the following:

   (1)  A remedial investigation report under a site-specific remediation.

   (2)  A baseline environmental report under an SIA cleanup.

 (a)  Resubmission of a cleanup plan, remedial investigation, risk assessment or final report will require payment of the appropriate fee identified in the act for each resubmission.

 (a)  A release of a regulated substance at a solid waste facility which did not receive waste after September 7, 1980, shall be remediated in accordance with this chapter and the act.

 (b)  Nothing in this chapter affects the permitting, operation, design, performance or closure requirements under the environmental protection acts or regulations thereunder. The remediation standards as defined in Chapters 271 and 287 (relating to municipal waste management—general provisions; and residual waste management—general provisions), do not substitute for design and performance standards required under the solid waste management regulations. See Articles VIII and IX (relating to municipal waste; and residual waste management). In the case of hazardous waste facilities, remediations shall comply with requirements applicable under the Resource Conservation and Recovery Act (42 U.S.C.A. § §  6091—6986).

 (c)  An unpermitted release or spill of a regulated substance at a permitted solid waste facility that is outside a disposal or processing unit, including surface impoundments, waste storage areas, associated piping and underlying containment systems, shall be remediated in accordance with this chapter and the act.

   The provisions of this §  250.9 amended under sections 5(b) and 402 of The Clean Streams Law (35 P. S. § §  691.5(b) and 691.402); section 302 of the Municipal Waste Planning, Recycling and Waste Reduction Act (53 P. S. §  4000.302); section 408(e) of the Pennsylvania Used Oil Recycling Act (58 P. S. §  408(e)); sections 1905-A, 1917-A and 1920-A of The Administrative Code of 1929 (71 P. S. § §  510-5, 510-17 and 510-20); sections 104(a), 301(c) and 303(a) of the Land Recycling and Environmental Remediation Standards Act (35 P. S. § §  6026.104(a), 6026.301(c) and 6026.303(a)); section 105(4) of the Waste Tire Recycling Act (35 P. S. §  6029.105(4)); sections 301 and 302 of the Radiation Protection Act (35 P. S. § §  7110.301 and 7110.302); and the Vehicle Code, 75 Pa.C.S. §  4909(e).

 (a)  For measuring regulated substances in soil and sediments, analyses shall be performed on a dry weight basis.

 (b)  For metals in soil, analyses shall be performed on total metals, except for hexavalent and trivalent chromium, which analyses shall be performed individually.

 (c)  For groundwater, samples for metals analysis shall be field filtered and field acidified in accordance with the most current version of the Groundwater Monitoring Guidance Manual, Department of Environmental Protection, 3610-BK-DEP1973.

 (d)  For groundwater where monitoring is being performed at a drinking water well, samples for metals analysis shall be field acidified and unfiltered in accordance with the most current version of Groundwater Monitoring Guidance Manual, Department of Environmental Protection, 3610-BK-DEP1973.

 (e)  For surface water, samples for metals analysis shall be field acidified in accordance with approved EPA analytical methods in §  16.102 (relating to approved EPA analytical methods and detection limits).

 (f)  For air, samples and analyses shall be performed in accordance with Chapters 131 and 139 (relating to ambient air quality standards; and sampling and testing).

Subchapter B. BACKGROUND STANDARD

Sec.

 (a)  Background concentrations shall be established based on a site characterization, as set forth in §  250.204(a)—(e) (relating to final report).

 (b)  The background concentrations shall be established using analysis of samples of regulated substances present at the property but not related to any release at the property. If all areas on the property are affected by a release, background shall be determined at points off the property in accordance with §  250.204(f)(7) and (8).

 (c)  Background concentrations shall be established by a methodology that is statistically valid and consistent with the methodology used to demonstrate attainment under Subchapter G (relating to demonstration of attainment).

 (a)  For attainment of the background standard for groundwater, the point of compliance shall be throughout the contaminant plume, including areas of the plume that are outside the property boundary, as determined by the site characterization.

 (b)  For attainment of a background soil standard, the point of compliance shall be throughout the area of the soil that has become contaminated as a result of releases on the property.

 (c)  For attainment of a surface water quality standard, compliance shall be measured for point source discharges at the point of discharge in accordance with limits specified in the NPDES permit.

 (d)  For the emission of regulated substances to outdoor air, the point of compliance for any applicable air quality standard shall be as specified in the air quality regulations in Subpart C, Article III (relating to air resources).

 (a)  For sites remediated under the background standard, the person conducting the remediation shall submit a final report to the Department which documents attainment of the selected standard. The final report shall include site characterization information in subsections (b)—(e). The site characterization shall be conducted in accordance with scientifically recognized principles, standards and procedures. The level of detail in the investigation, and the selected methods and analyses, that may include models, shall sufficiently define the rate of movement and the present and future extent and fate of contaminants to ensure continued attainment of the remediation standard. Interpretations of geologic and hydrogeologic data shall be prepared by a professional geologist licensed in this Commonwealth.

 (b)  As derived from specific knowledge of the subject property, historic use of the subject property or regulated substance usage information regarding the subject property, an appropriate number of sample locations should be investigated from the identified media of concern to characterize the nature and composition of the contaminants including the following:

   (1)  Source characterization or development of a conceptual site model.

   (2)  The vertical and horizontal extent of contamination within each media of concern.

   (3)  The direction and rate of contaminant movement and fate and transport of all contaminants within each media of concern.

   (4)  A determination of the appropriate remedial technology for each media of concern.

 (c)  Descriptions of sampling and decontamination methodologies and analytical quality assurance/quality control procedures should be included within a Sampling and Analysis Plan and Quality Assurance Plan. Copies of soil and geologic boring descriptions and as-built construction drawings of wells used for site characterization should be included in the report. Copies of laboratory analytical results and applicable laboratory quality control results should be included within the report, including historical data and data eliminated from consideration based on data validation protocols. Analytical results should be presented within the report in table form.

 (d)  If soil is determined to be a media of concern, the site characterization shall determine the relative location of soil samples necessary to characterize the horizontal and vertical extent of contamination based on factors such as hydraulic conductivity of the soils, heterogeneity of the soils and the nature of the contaminants. The horizontal and vertical extent of soil with concentrations of regulated substances above the selected standard shall be defined by an appropriate number of samples inside and outside of the area that exceeds the standard. Soil samples from the area with the anticipated highest levels of contamination shall be obtained, as appropriate, to determine the applicability of the proposed remedial action or handling and disposal requirements, or both, for that soil during remediation.

 (e)  If groundwater is determined to be a media of concern, the site characterization shall characterize the effects of a release on groundwater to adequately determine how naturally occurring physical and geochemical characteristics define the movement of groundwater and contaminants beneath the surface, including the delineation of the position of aquifers, as well as geologic units which inhibit groundwater flow. The site characterization shall meet the following conditions:

   (1)  If appropriate, the characterization shall consider the heterogeneity and anisotropy of aquifer materials based on hydraulic conductivity values (measured or published), and the effect of local and regional groundwater flow directions and any influence from pumping wells.

   (2)  Defining the horizontal extent of concentrations of regulated substances above the standard shall require more than one round of groundwater sampling from properly constructed and developed monitoring wells taken a sufficient number of days apart to yield independently valid results.

   (3)  When characterizing the vertical extent of groundwater contamination, the person shall perform more than one round of groundwater sampling and shall consider the specific gravity of the regulated substances identified in the groundwater in the site, and the potential for naturally occurring or induced downward vertical hydraulic gradients.

   (4)  When characterizing the vertical extent of groundwater contamination, properly constructed monitoring wells or nested monitoring wells should be utilized to focus groundwater sampling in zones of potential contaminant accumulation such as zones directly above a confining layer. Samples shall be taken a sufficient number of days apart to yield independently valid results.

 (f)  Final reports for the background standard shall include the following additional information:

   (1)  Descriptions of treatment, removal or decontamination procedures performed in remediation. The description shall include the methodology and analytical results used to direct the remediation and determine the cessation of remediation.

   (2)  Descriptions of the sampling methodology and analytical results, including the appropriate statistical methodologies, which pertain to whether the remediation has attained the selected standard, following the requirements of Subchapter G (relating to demonstration of attainment).

   (3)  Documentation of compliance with postremediation care requirements, if they are needed to maintain the selected standard.

   (4)  All sampling data.

   (5)  For fate and transport analyses, submission of the following information:

     (i)   The name and version of the analysis, a description of the analysis, and the name of the organization or person which developed the analysis, if modeling is used.

     (ii)   The site characterization data used in the analysis.

     (iii)   Any assumptions used in the analysis and justification for the assumptions.

     (iv)   Appropriate documentation of the quality assurance and quality control of the analysis.

     (v)   Documentation of the results of the analysis in appropriate figures and tables.

   (6)  A summary of sampling methodology and analytical results that relate to the determination of the background concentration. The summary shall contain the following:

     (i)   For soil, the final report shall identify the background reference region within which all background samples were collected.

     (ii)   For groundwater, the final report shall identify background reference wells.

   (7)  Documentation that background reference areas for soil meet the following criteria:

     (i)   The background reference region and background reference areas shall be free of contamination from any release at the site.

     (ii)   Sampling at the background reference area and the contaminated area shall be comparable and random.

     (iii)   A background reference area selected for comparison with a given contaminated area may not differ significantly from that contaminated area in physical, chemical or biological characteristics that might cause measurements in the background reference area and the contaminated area to differ.

   (8)  Documentation that background reference groundwater concentrations have been determined at hydrogeologically upgradient points that characterize the groundwater flow onto the site that are not affected by any release at the property.

 (g)  If engineering controls are needed to attain or maintain a standard, if institutional controls are needed to maintain a standard, if the fate and transport analysis indicates that the remediation standard may be exceeded at the point of compliance in the future, or, if the remediation relies on natural attenuation, a postremediation care plan shall be documented in the final report. The plan shall include the following:

   (1)  Reporting of any instance of nonattainment.

   (2)  Reporting of measures to correct nonattainment conditions.

   (3)  Monitoring on a quarterly basis, or as otherwise approved by the Department, that demonstrates the effectiveness of the remedy and periodic reporting of monitoring results and analysis.

   (4)  Maintenance of records at the property where the remediation is being conducted for monitoring, sampling and analysis.

   (5)  A schedule for operation and maintenance of the controls and submission of proposed changes.

   (6)  If requested by the Department, documentation of financial ability to implement the remedy and the postremediation care plan.

   This section cited in 25 Pa. Code §  245.312 (relating to remedial action); 25 Pa. Code §  245.313 (relating to remedial action completion report); 25 Pa. Code §  250.202 (relating to establishing background concentrations); 25 Pa. Code §  250.312 (relating to final report); and 25 Pa. Code §  250.411 (relating to final report).

Subchapter C. STATEWIDE HEALTH STANDARDS

Sec.

 (a)  This subchapter sets forth generic Statewide health standards as one of three remediation standards that a person may select. The Statewide health standards are concentrations of regulated substances associated with a specific environmental medium, and are designated as the MSCs. The values used to determine the MSCs are contained in Appendix A, Tables 1—4 and 6 and are the concentrations of regulated substances that shall be met to demonstrate attainment of a Statewide health standard. Appendix A, Table 5 presents the toxicological and physical parameters used to calculate the MSCs in Appendix A, Tables 1—4.

 (b)  This subchapter sets forth minimum threshold MSCs for soil and groundwater that shall be met to demonstrate attainment of the Statewide health standards for regulated substances in Appendix A, Table 6. Minimum threshold MSCs are standards developed for regulated substances for which no chemical-specific toxicological data exist.

 (a)  For attainment of the Statewide health standard for groundwater, the point of compliance is the property boundary that existed at the time the contamination was discovered. Statewide health standards shall be attained at and beyond the point of compliance. The Department may determine, in writing, a point of compliance beyond the property boundary to be appropriate if one of the following situations is demonstrated:

   (1)  Structures are located on the property boundary which prohibit internal or external access for a drill rig.

   (2)  The property is a small parcel of land with limited space for onsite monitoring wells.

   (3)  It is not physically possible to monitor groundwater quality at the property boundary.

   (4)  The downgradient property was owned by the same party at the time the contamination was discovered and the use of the groundwater on the downgradient property can be controlled to prevent unacceptable exposure.

   (5)  For measuring compliance with the groundwater MSCs that apply to secondary contaminants.

 (b)  For attainment of the Statewide health standard for soil, the MSC as determined in §  250.305 (relating to MSCs for soil) shall be met at the specified depth.

 (c)  For the emission of regulated substances to outdoor air, the point of compliance for any applicable air quality standard shall be as specified in the air quality regulations.

 (a)  With the exception of seasonal, localized and hydrologically isolated perched systems under a property, all geologic formations or parts or groups of formations in this Commonwealth which are saturated are presumed to be aquifers for the purpose of applying the Statewide health standards. The term includes saturated residuum such as saprolite and other weathered rock strata or intervals developed from underlying bedrock and other saturated deposits overlying these formations to which the geologic formations are hydrologically connected.

 (b)  All groundwater in aquifers is presumed to be used or currently planned for use, unless determined otherwise by the Department under this section.

   (1)  The Department may determine, in writing, based on a demonstration by the person remediating a site identified in an NIR, that groundwater is not used or currently planned to be used, if:

     (i)   The public participation requirements of §  250.5 (relating to public notice by applicant) are met.

     (ii)   The requirements in subsection (c) are met within the site on the property and within a radius of 1,000 feet downgradient of the points of compliance plus any additional areas to which the contamination has migrated and might reasonably migrate at concentrations that exceed the MSC for groundwater used or currently planned to be used.

   (2)  Methods appropriate for determining current or currently planned future use may include door-to-door surveys, verifying community water system billing records and interviewing community water system suppliers with regard to their currently planned future groundwater use.

 (c)  The following requirements shall be met within the area described in subsection (b):

   (1)  No groundwater derived from wells or springs is used for drinking water or agricultural purposes.

   (2)  All downgradient properties are connected to a community water system.

   (3)  The area described in subsection (b) does not intersect a radius of 1/2 mile from a community water supply well source or does not intersect an area designated by the Department as a zone 2 wellhead protection area under Chapter 109 (relating to safe drinking water).

   (4)  At the time the nonuse aquifer determination request under subsection (b) is submitted to the Department, there are no existing documents developed by political subdivisions or community water system suppliers detailing the implementation of groundwater resources development (that is, no currently planned future uses) in the area specified in subsection (b)(1)(ii).

 (d)  If the Department determines that groundwater is not used or currently planned to be used, the following requirements apply within the area identified in subsection (b):

   (1)  The requirements in §  250.309 (relating to MSCs for surface water).

   (2)  The ecological screening process identified in §  250.311 (relating to evaluation of ecological receptors).

   (3)  The remediator shall establish institutional controls to maintain the integrity of the nonuse aquifer determination, or include a postremediation care plan in the final report detailing the process of routinely assessing and reporting to the Department compliance with subsection (c).

     (i)   Postremediation care plan provisions shall be acknowledged within the deed to the remediated property upon transfer of ownership to insure compliance with subsection (c).

     (ii)   Postremediation assessment and reporting requirements shall continue until the property owner can demonstrate that the MSC for groundwater in aquifers used or currently planned for use is not exceeded at the point of compliance, and fate and transport analysis shows that the MSC will not be exceeded at that point in the future.

 (e)  The MSCs for groundwater in an aquifer that is not used or currently planned for use, under §  250.304(d) (relating to MSCs for groundwater), shall be met at the points of compliance identified in §  250.302 (relating to point of compliance)

 (f)  A nonuse aquifer areawide certification obtained under this subsection may be used by the remediator to demonstrate that the requirements of subsection (c) are met.

   (1)  With or without the presence of an associated NIR, the Department may determine, in writing, based on a demonstration by a municipal authority or political subdivision, that groundwater is not used or currently planned to be used in a specific geographic area, if the following conditions exist:

     (i)   The municipal authority or political subdivision demonstrates that the requirements of subsection (c) are met in the specific geographic area.

     (ii)   Municipal ordinances are in effect that prohibit the use of groundwater from wells or springs for drinking water or agricultural purposes.

     (iii)   Municipal ordinances are in effect that require all water users to connect to a community water supply system.

   (2)  If the municipal ordinances relied upon to make the demonstration in paragraph (1) are amended or repealed, the political subdivision or municipal authority who requested the areawide designation shall notify the Department in writing within 30 days of the effective date of the amendment or repeal.

   The provisions of this §  250.303 amended November 23, 2001, effective November 24, 2001, 31 Pa.B. 6395. Immediately preceding text appears at serial pages (233650) to (233651).

 (a)  A person shall implement a remedy under the Statewide health standard that is protective of human health and the environment.

 (b)  The MSCs for regulated substances in groundwater are presented in Appendix A, Tables 1 and 2. The methodology used by the Department for calculating MSCs in groundwater is detailed in subsections (c)—(f).

 (c)  The MSCs for regulated substances contained in groundwater in aquifers used or currently planned to be used for drinking water or for agricultural purposes is the MCL as established by the Department or the EPA (U. S. EPA, 1996. Drinking Water Regulations and Health Advisories. Office of Water. EPA 822-R-96-001). For a regulated substance where no MCL has been established, the MSC is the lifetime health advisory level (HAL) for that compound. For a regulated substance where neither an MCL nor a lifetime HAL is established, the MSC is the lowest concentration calculated using the appropriate residential and nonresidential exposure assumptions and the equations in § §  250.306 and 250.307 (relating to ingestion numeric values; and inhalation numeric values).

 (d)  For regulated substances contained in aquifers not used or currently planned to be used, the MSCs in Appendix A, Tables 1 and 2 are calculated by the following:

   (1)  For volatile organic regulated substances with an attenuation factor of less than 20, as calculated by the methodology in paragraph (7), ten times the appropriate residential or nonresidential MSC for groundwater in aquifers used or currently planned to be used containing less than 2,500 mg/l total dissolved solids.

   (2)  For volatile organic regulated substances with an attenuation factor of greater than or equal to 20, as calculated by the methodology in paragraph (7), 100 times the appropriate residential or nonresidential MSC for groundwater in aquifers used or currently planned to be used containing less than 2,500 mg/l total dissolved solids.

   (3)  For semivolatile organic and inorganic regulated substances, regardless of the attenuation factor, 1,000 times the appropriate residential or nonresidential MSC for groundwater in aquifers used or currently planned to be used containing less than 2,500 mg/l total dissolved solids.

   (4)  For benzene, 100 times the appropriate residential or nonresidential MSC for groundwater in aquifers used or currently planned to be used containing less than 2,500 mg/l total dissolved solids.

   (5)  For regulated substances with no calculated attenuation factor because of a lack of data in Howard, P. H., R. S. Boethling, W. F. Jarais, W. M. Meylan and E. M. Michalenko. 1991. Handbook of Environmental Degradation Rates. Lewis Publishers, Inc., Chelsea, MI., the appropriate residential or nonresidential MSC for groundwater in aquifers used or currently planned to be used containing less than 2,500 mg/l total dissolved solids.

   (6)  For minimum threshold MSCs, 5 micrograms per liter in groundwater shall be used.

   (7)  The attenuation factor (AF) for an organic regulated substance shall be calculated according to the following formula:

 AF = K x KOC

 Where:

 K = degradation coefficient = 0.693

                T_1/2

 T1/2—half-life of organic regulated substance in groundwater as reported in Howard, P. H., R. S. Boethling, W. F. Jarais, W. M. Meylan and E. M. Michalenko, 1991. Handbook of Environmental Degradation Rates. Lewis Publishers, Inc., Chelsea, MI.

 KOC—organic carbon partitioning coefficient (See Appendix A Table 5).

 (e)  If the groundwater in aquifers used or currently planned for use at the site has naturally occurring background total dissolved solids concentrations greater than 2,500 milligrams per liter, the Statewide health standard for a regulated substance dissolved in the groundwater may be adjusted by multiplying the MSC for groundwater in aquifers by 100. The adjusted Statewide health standard shall then be used in calculating the soil to groundwater pathway numeric value as specified in §  250.308 (relating to soil to groundwater pathway numeric values).

 (f)  In addition to the requirements in this section, the MSCs are further limited by solubility as identified in Appendix A, Table 5. The solubility limits are derived from the references in subsection (g), which are keyed to the numbers in Table 5. The following procedure was used to determine the appropriate solubility value for each regulated substance: where multiple sources are cited in Table 5, the value for the solubility limit is the median of the values in the indicated references.

   (1)  Using the hierarchy established in subsection (g), the first two references were consulted. If the solubility values agreed within 5%, the selected value is the lower of the two values.

   (2)  If the values in step (1) did not agree within 5%, the next references in order were consulted until two values that did agree within 5% were found. The selected value is then the median of all the values consulted.

   (3)  If none of the values in all of the references in subsection (g) agreed within 5%, the selected value is the median of all values in all references.

 (g)  The references referred to in subsection (f) are:

   (1)  Lide, D. R., ed. 1996. CRC Handbook of Chemistry and Physics, 77th Edition. CRC Press.

   (2)  Budavari, S., ed. 1996. The Merck Index, 12th Ed. Merck and Co.

   (3)  Perry, R. H., et al. 1997. Perry’s Chemical Engineer’s Handbook, 7th ed. McGraw-Hill, New York.

   (4)  Howard, P. H. 1991. Handbook of Environmental Fate and Exposure Data for Organic Chemicals. Vol. III Pesticides, Lewis Publishers.

   (5)  Verschueren, K. 1977, Handbook of Environmental Data on Organic Chemicals, Van Nostrand Reinhold.

   (6)  MacKay, D., et al. 1997, Illustrated Handbook of Physical-Chemical Properties and Environmental Fate for Organic Chemicals, 5 Volumes. Lewis Publishers, New York.

   (7)  Montgomery, J. H. 1991, Groundwater Chemicals Desk Reference, Vol. II. Lewis Publishers and Montgomery, J. H., and L. M. Welkom. 1990, Groundwater Chemicals Desk Reference Vol I, Louis Publishers.

   (8)  Milne, G.W.A., ed. 1995, CRC Handbook of Pesticides, CRC Press, Inc.

   (9)  National Library of Medicine (Grateful Med), Hazardous Substances Databank.

   (10)  EPA. 1994, Superfund Chemical Data Matrix. Office of Solid Waste and Emergency Response, EPA 540-R-94-009.

   (11)  Mabey, et al. 1982, Aquatic Fate Process Data for Organic Priority Pollutants, SRI. EPA Contract Nos. 68-01-3867, 68-03-2981.

   The provisions of this §  250.304 amended November 23, 2001, effective November 24, 2001, 31 Pa.B. 6395. Immediately preceding text appears at serial pages (233652) and (272687).

 (a)  A person shall implement a remedy under the Statewide health standard that is protective of human health and the environment.

 (b)  The MSCs for regulated substances in soil are presented in Appendix A, Tables 3 and 4. The methodology for calculating MSCs in soil is detailed in subsections (c)—(e) and the MSCs are further limited to not exceed the physical capacity of the soil to contain a regulated substance. This physical limitation is based on an assumed porosity of 0.35, an assumed dry bulk density of soil of 1.8 kilograms per liter and an assumed density of a regulated substance of 1.0 kilograms per liter. This is calculated according to the equation in paragraph (1). For regulated substances which are organics and liquids at standard temperature and pressure (STP) as identified in Appendix A, Table 5 (Chemical Properties), the physical limitation is further limited based on residual saturation with the additional assumption of a residual saturation ratio of substance volume to soil volume of 0.051, as calculated in Equation (2).

 where:
 [rho ]_rs = density of the regulated substance = 1.0 kg/L
 n = porosity of the soil = 0.35
 [rho ]_B = dry bulk density of the soil = 1.8 kg/L
 Sr = residual saturation ratio (substance vol./soil vol.) = 0.051

 (c)  For the residential standard, the MSC for regulated substances contained in soil is one of the following:

   (1)  The lowest of the following:

     (i)   The ingestion numeric value throughout the soil column to a depth of up to 15 feet from the existing ground surface as determined by the methodology in §  250.306 (relating to ingestion numeric values), using the appropriate default residential exposure assumptions contained in §  250.306(e).

     (ii)   The inhalation numeric value throughout the soil column to a depth of up to 15 feet in soil from the existing ground surface, which considers volatilization into the outdoor air and inhalation of particulates, as determined by the methodology in §  250.307 (relating to inhalation numeric values), using the appropriate default residential exposure assumptions contained in §  250.307(d).

     (iii)   The soil-to-groundwater pathway numeric value throughout the entire soil column as determined by the methodology in §  250.308 (relating to soil to groundwater pathway numeric values).

   (2)  The lowest of paragraph (1)(i) and (ii) and, in addition, one of the following:

     (i)   A demonstration of the soil-to-groundwater pathway soil buffer as identified in §  250.308(b), if applicable.

     (ii)   A soil-to-groundwater pathway equivalency demonstration as identified in §  250.308(d).

 (d)  For the nonresidential standard, the MSC for regulated substances contained in soil throughout the soil column to a depth of 2 feet from the existing ground surface is one of the following:

   (1)  The lowest of the following:

     (i)   The ingestion numeric value as determined by the methodology in §  250.306, using the appropriate default nonresidential exposure assumptions contained in §  250.306(e).

     (ii)   The inhalation numeric value which is the lower of the values for volatilization into the outdoor air and the inhalation of particulates, as determined by the methodology in §  250.307, using the appropriate default nonresidential exposure assumptions contained in §  250.307(d).

     (iii)   The soil-to-groundwater pathway numeric value throughout the entire soil column as determined by the methodology in §  250.308.

   (2)  The lowest of paragraph (1)(i) or (ii) and, in addition, one of the following:

     (i)   A demonstration of the soil-to-groundwater pathway soil buffer as identified in §  250.308(b), if applicable.

     (ii)   A soil-to-groundwater pathway equivalency demonstration as identified in §  250.308(d).

 (e)  For the nonresidential standard, the MSC for regulated substances contained in soils at depths greater than 2 feet through 15 feet from the existing ground surface, is one of the following:

   (1)  The lowest of the following:

     (i)   The inhalation numeric value which considers volatilization to the outdoor air, as determined by the methodology in §  250.307, using the appropriate default nonresidential exposure assumptions contained in §  250.307(d), and using a transfer factor (TF) based upon the calculated emission rate from subsurface soil as specified in the method of Jury, et al. 1990. Water Resources Research, Vol. 26, No. 1, pp. 13—20.

     (ii)   The soil-to-groundwater pathway numeric value throughout the entire soil column as determined by the methodology in §  250.308.

   (2)  The value identified in paragraph (1)(i) and one of the following:

     (i)   A demonstration of the soil-to-groundwater pathway soil buffer as identified in §  250.308(b), if applicable.

     (ii)   A soil-to-groundwater pathway equivalency demonstration as identified in §  250.308(d).

 (f)  The MSC for regulated substances contained in soil at depths greater than 15 feet is one of the following:

     (i)   The soil-to-groundwater pathway numeric value as determined by §  250.308(a).

     (ii)   A demonstration of the soil-to-groundwater pathway soil buffer as identified in §  250.308(b), if applicable.

     (iii)   A soil-to-groundwater pathway equivalency demonstration as identified in §  250.308(d).

 (g)  A person conducting a remediation of soils contaminated with a substance having a secondary MCL will not be required to comply with the soil-to-groundwater pathway requirements for those substances to protect groundwater in aquifers for drinking water.

 (a)  For a regulated substance which is a systemic toxicant, the ingestion numeric value for that substance was calculated using the appropriate residential or nonresidential exposure assumptions from subsection (d) according to the following equation:

 (b)  For a regulated substance which is a carcinogen, the ingestion numeric value for that substance was calculated using the appropriate residential or nonresidential exposure assumptions from subsection (d) according to the following equation:

 (c)  For a regulated substance that has both an oral reference dose and an oral cancer slope factor, the ingestion numeric value is the lower of the two numbers as calculated by the equations in subsections (a) and (b).

 (d)  The default exposure assumptions used to calculate the ingestion numeric values are as follows:

   Notes:
¹Residential exposure to noncarcinogens is based on childhood (ages 1-6) exposure for soil, and adult exposure for groundwater, consistent with USEPA (1991).
²Residential exposure to carcinogens is based on combined childhood and adult exposure.
³The oral absorption factor takes into account absorption and bioavailability. In cases where the oral RfD or CSF is based on administered oral dose, the absorption factor would be limited to bioavailability. The default value is 1.
⁴The Ingestion Factor for the residential scenario is calculated using the equation If_adj = ED_c x IR_c/BW_c + ED_a x IR_a/Bw_a, where ED_c = 6 yr, IR_c = 100 mg/day for soils and 1 L/day for groundwater, BW_c = 15 kg, ED_a = 24 yr, IR_a = 50 mg/day for soils and 2 L/day for groundwater, and BW_a = 70 kg. The ingestion factor for the nonresidential scenario is calculated using the equation If_adj = ED x IR/BW, where ED = 25 yr, IR = 50 mg/day for soils and 1 L/day for groundwater, and BW = 70 kg.
⁵In cases where the inhalation RfD or CSF is based on absorbed dose, this factor can be applied in the exposure algorithm. The default value is 1.

 (e) The residential ingestion numeric value for lead in soil was developed using the Uptake Biokinetic (UBK) Model for Lead (version 0.4) developed by the EPA (U. S. Environmental Protection Agency. (1990). Uptake Biokinetic (UBK) Model for Lead (version 0.4). U. S. EPA/ECAO. August 1990, in lieu of the algorithms presented in subsections (a) and (b). Default input values are identified in Appendix A, Table 7. Because the UBK model is applicable only to children, the nonresidential ingestion numeric value was calculated according to the method developed by the Society for Environmental Geochemistry and Health (Wixson, B. G. (1991)). The Society for Environmental Geochemistry and Health (SEGH) Task Force Approach to the Assessment of Lead in Soil. Trace Substances in Environmental Health. (11-20), using the following equations:

 Table 7 identifies each of the variables in this equation.

 (a)  For a regulated substance which is a systemic toxi- cant, the following applies:

   (1)  For a volatile compound, the numeric value for inhalation from soil shall be calculated using the appropriate residential or nonresidential exposure assumptions from subsection (d) according to the following equation using TF for volatiles:

   (2)  For a regulated substance attached to particulates, the numeric value for inhalation from soil was calculated using the appropriate residential or nonresidential exposure assumptions from subsection (d) according to the equation in paragraph (1) using TF for particulates.

 (b)  For a regulated substance which is a carcinogen, the following apply:

   (1)  For a volatile compound, the numeric value for inhalation from soil was calculated using the appropriate residential or nonresidential exposure assumptions from subsection (d) according to the following equation using TF for volatiles:

   (2)  For a regulated substance attached to particulates, the numeric value for inhalation from soil was calculated using the appropriate residential or nonresidential exposure assumptions from subsection (d) according to the equation in paragraph (1) using TF for particulates.

 (c)  For a regulated substance which is both a systemic toxicant and a carcinogen, the inhalation numeric value is the lower of the two numbers as calculated by the equations in subsections (a) and (b).

 (d)  The default exposure assumptions used to calculate the inhalation numeric values for soil are as follows:

   Notes: Modified from USEPA Region III Risk-based Concentration Table, dated October 20, 1995.
N/A = Not Applicable
¹Residential exposure to systemic toxicants is based on adult exposure, consistent with USEPA (1991).
²Residential exposure to carcinogens is based on combined child and adult exposure.
³Volatilization transport factor is calculated using TF = (ER x DF)^-1, where DF = 12 (mg/m³)/(m²-sec). See soil depth-specific algorithm for the calculation of ER.
⁴Particulate transfer factor was calculated using TF = (ER x DF)^-1, where ER = 8.25 x 10^-12 (mg/m²-sec)/(mg/kg) and DF = 12(mg/m³)/(mg/m²-sec).
⁵In cases where the inhalation RfD or CSF is based on absorbed dose, this factor can be applied in the exposure algorithm. The default value is 1.
⁶Assumes approximately 100 days/yr with the ground being frozen. Exposure to surficial soils when the ground is frozen is considered de minimis. The nonresidential exposure frequency is defined as 5/7 x 250 days/yr.
⁷The inhalation factor for the residential scenario is calculated using the equation IF_adj = ED_c x IR_c/BW_c + ED_a x IR_a/Bw_a, where ED_c = 6 yr, IR_c = 0.5 m³/hr, BW_c = 15kg, ED_a = 24 yr, IR_a = 0.83 m³/hr, and BW_a = 70 kg. The inhalation factor for the nonresidential scenario is calculated using the equation IF_adj = ED x IR/BW, where ED = 25 yr, IR = 1.25 m³/hr and BW = 70 kg.

 (e)  For the inhalation numeric values in subsections (a) and (b), the TF was calculated by the following equation:

 TF = (ER x DF)^-1

 The Dispersion Factor (DF) value of 12 (mg/m³)/(mg/m²/sec) is taken from the default value in the EPA Draft Soil Screening Guidance (U. S. EPA, 1994. Technical Background Document for Soil Screening Guidance. Review Draft. Office of Emergency and Remedial Response. EPA-540/R-94/106) and the Emission Rate (ER) is calculated by the following equations (from Jury et al. 1990. Water Resources Research, Vol. 26. No. 1. pp. 13-20):

   ⁽¹⁾All default values from USEPA (1994) Draft Soil Screening Guidance, EPA-540/R-94/106, except as noted.
⁽²⁾Consistent with Standards Subcommittee recommendation.
⁽³⁾Based on Act 2 SAB-agreed depths.
⁽⁴⁾The Risk Assessment Subcommittee selected a f_oc of 0.005, which falls between f_oc’s of 0.006 for surface soil and 0.002 for subsurface soil.

 (f)  For a regulated substance which is a systemic toxicant and is a volatile compound, the numeric value for the inhalation of volatiles from groundwater was calculated by using the appropriate residential or nonresidential exposure assumptions from subsection (h) according to the following equation:

 (g)  For a regulated substance which is a carcinogen and is a volatile compound, the numeric value for the inhalation of volatiles from groundwater shall be calculated by using the appropriate residential or nonresidential exposure assumptions from subsection (h) according to the following equation:

 (h)  The default exposure assumptions used to calculate the inhalation numeric values for the inhalation of volatiles from groundwater are as follows:

   (Footnotes on next page)

   Notes: Modified from USEPA Region III Risk-based Concentration Table, dated October 20, 1995.
N/A = Not Applicable
¹Residential exposure to systemic toxicants is based on adult exposure, consistent with USEPA (1991).
²Residential exposure to carcinogens is based on combined child and adult exposure.
³In cases where the inhalation RfD or CSF is based on absorbed dose, this factor can be applied in the exposure algorithm.
⁴Default Transfer Factor is as presented in USEPA’s RAGS, Part B.
⁵The inhalation factor for the residential scenario is calculated using the equation IF_adj = ED_c x IR_c/BW_c + ED_a x IR_a/Bw_a, where ED_c = 6 yr, IR_c = 0.5 m³/hr, BW_c = 15 kg, ED_a = 24 yr, IR_a = 0.625 m³/hr, and BW_a = 70 kg. The inhalation factor for the nonresidential scenario is calculated using the equation IF_adj = ED x IR/BW, where ED = 25 yr, IR = 1.25 m³/hr and BW = 70 kg.

 (a)  A person may use the soil-to-groundwater pathway numeric values listed in Appendix A, Table 3B, as developed using the methods contained in paragraph (1), (2) or (4), may use a concentration in soil at the site which does not produce a leachate in excess of the MSC for groundwater contained in Appendix A, Tables 1 and 2, when subjected to the Synthetic Precipitation Leaching Procedure (Method 1312 of SW-846, Test Methods for Evaluating Solid Waste, promulgated by the U. S. EPA), or may use the soil-to-groundwater pathway soil buffer criteria in subsection (b) or may use the soil-to-groundwater pathway equivalency demonstration in subsection (d).

   (1)  A value which is 100 times the applicable MSC for groundwater identified in §  250.304(c) or (d) (relating to MSCs for groundwater), expressed as milligrams per kilogram of soil.

   (2)  For organic compounds, a generic value determined not to produce a concentration in groundwater in the aquifer in excess of the MSC for groundwater as calculated by the equation in paragraph (3).

     (i)   For soil not in the zone of groundwater saturation, the generic value shall be calculated by the equation in paragraph (3).

     (ii)   For soil in the zone of groundwater saturation, the standard is 1/10th of the generic value calculated by the equation in paragraph (3).

   (3)  The equation referenced in paragraphs (1) and (2) is the following:

 where: MSC_S (mg/kg) = the generic value for a regulated substance in soil

 MSC_GW (mg/L) = MSC of a regulated substance in groundwater

 K_oc (L/kg) = organic carbon partition coefficient for a regulated substance

 f_oc = fraction of organic carbon in soil (default value = 0.0025)

 [thgr ]_w = water-filled porosity of soil (default value = 0.2)

 [rho ]_b (kg/L) = dry bulk density of soil (default value = 1.8 kg/l)

 DF = dilution factor (default value = 100)

   (4)  For inorganic regulated substances, a generic value determined not to produce a concentration in groundwater in the aquifer in excess of the MSC for groundwater as calculated by the equation in paragraph (5) and listed in Appendix A, Table 4B.

     (i)   For soil not in the zone of groundwater saturation, the generic value shall be calculated by the equation in paragraph (5).

     (ii)   For soil in the zone of groundwater saturation, the standard is 1/10th of the generic value calculated by the equation in paragraph (5).

   (5)  The equation referenced in paragraph (4) is the following:

 where: MSC_S (mg/kg) = the generic value for the inorganic regulated substance in soil

 MSC_GW (mg/L) = MSC of the inorganic regulated substance in groundwater

 K_d (L/kg) = soil to water partition coefficient for the inorganic regulated substance

 [thgr ]_w = water-filled porosity of soil (default value = 0.2)

 [rho ]_b (kg/L) = dry bulk density of soil (default value = 1.8 kg/L)

 DF = dilution factor (default value = 100)

 (b)  The soil-to-groundwater pathway soil buffer is the entire area between the bottom of the area of contamination and the groundwater or bedrock and shall meet the following criteria:

   (1)  The soil depths established in Appendix A, Tables 3B and 4B for each regulated substance.

   (2)  The concentration of the regulated substance cannot exceed the limit related to the PQL or background throughout the soil buffer.

   (3)  No Karst carbonate formation underlies or is within 100 feet of the perimeter of the contaminated soil area.

 (c)  The soil-to-groundwater pathway soil buffer distances were developed by using the following equations.

   (1)  The following equations were used iteratively for each layer of soil for each time increment in a total time period of 30 years and pertain to a soil column where the first 4 feet of soil are contaminated with a regulated substance at a concentration of 10,000 mg/kg.

 where: C_soil(it) (mg/kg) = concentration of regulated substance in soil at layer i at time increment TI

 C_soil(i(t-1)) (mg/kg) = concentration of regulated substance in soil at layer i at time increment immediately preceding TI

 C_{soil(i+1)(t-1)} (mg/kg) = concentration of regulated substance in soil at layer immediately above layer i at time increment immediately preceding TI

 R (cm/yr) = recharge rate of water infiltrating soil (default value = 33 cm/yr)

 DI (feet) = thickness of each layer i of soil (default value = 1 foot)

 [rho ]_b (kg/L) = dry bulk density of soil (default value = 1.8 kg/L)

 360 (month-cm/yr-ft) = conversion factor

 TI (months) = time duration of each time increment

 [thgr ]_W = water-filled porosity (default value = 0.2)

 C_aq(i(t-1)) (mg/L) = concentration of regulated substance in soil pore water at layer i at time increment immediately preceding TI

 C_aq(i+1)(t-1) (mg/L) = concentration of regulated substance in soil pore water at layer immediately above layer i at time increment immediately preceding TI

 K_d (L/kg) = soil to water partition coefficient for the regulated substance where five different contaminant-specific values are used: 2.5, 5, 10, 100 and 1,000.

 K_d values of organic regulated substances are based on the following equation:

 K_d = (f_oc)(K_oc)

 where: f_oc = fraction of organic carbon in soil (default value = 0.005)

 K_oc (L/kg) = organic carbon partition coefficient for a regulated substance

   (2)  The buffer distances listed for regulated substances in Tables 3B and 4B were determined by the Department using these equations to model the distance that the regulated substance travels from the bottom of the first 4 feet of contaminated soil through the soil column in 30 years at a concentration at or above 1 µG/L in the water infiltrating the soil.

 (d)  For any regulated substance, an equivalency demonstration may be substituted for the soil-to-groundwater numeric value throughout the site and the soil-to-groundwater pathway soil buffer if the groundwater is below the MSC value or the background standard prior to remediation. This equivalency demonstration shall include the following:

   (1)  Fate and transport analysis of the regulated substance from the deepest point of contamination in the soil through unsaturated zone soil and shall include the use of soil-to-water partition coefficients. The analysis shall demonstrate that the regulated substances will not migrate to bedrock or the groundwater within 30 years at concentrations exceeding the greater of the groundwater MSC or background in groundwater as the endpoint in soil pore water directly under the site.

   (2)  In addition to sampling required for attainment of the inhalation or ingestion numeric values for soils up to 15 feet, as applicable, reporting and monitoring for eight quarters that shows no exceedances of the greater of the groundwater MSCs or of the background standard for groundwater beneath the contaminated soil and no indications of an increasing trend of concentration over time that may exceed the standard.

 (a)  Any regulated discharge to surface waters shall comply with the applicable provisions of Chapters 91—96, 97 (reserved), 102, 103 and 105, including antidegradation requirements, and may not cause an exceedance of the applicable water quality standards for the surface water in question.

 (b)  For point source discharges to surface water, compliance shall be measured at the point of discharge in accordance with limits specified in the NPDES permit.

 (c)  For purposes of determining compliance with surface water quality standards from a diffuse surface or groundwater discharge, the person shall determine the expected instream regulated substance concentrations, that are attributable to releases at the site, using mass balance techniques for groundwater/surface water mixing at design flow conditions.

   (1)  If the results indicate that surface water quality standards are being achieved, no action is required.

   (2)  If results indicate that surface water quality standards are not being achieved, additional sampling may be performed to help evaluate whether surface water quality standards are being achieved.

   (3)  If the results of the sampling indicate surface water quality standards are being met, no further action is required.

   (4)  If the results of the modeling, and sampling if any, indicate that surface water quality standards are not being met, the person shall perform further remedial action to attain the surface water quality standards.

 (d)  Except if an NPDES permit is required, for purposes of complying with surface water quality standards in a spring, the point of compliance is the point of first designated or existing use, as defined in § §  93.1, 93.4 and 93.9 (relating to definitions; Statewide water uses; and designated water uses and water quality criteria). If the point of first designated or existing use occurs in a surface water into which a spring flows, compliance with surface water quality standards shall be determined in the manner specified in subsection (c).

 (a)  For regulated substances listed in Appendix A, Table 6 that are found in groundwater, the minimum threshold MSC of 5 micrograms per liter in groundwater, shall be used.

 (b)  For regulated substances listed in Appendix A, Table 6 that are found in soil, the lowest of one of the following values shall be used as the minimum threshold MSC:

   (1)  An ingestion numeric value of 100 milligrams per kilogram in soil.

   (2)  The soil-to-groundwater pathway numeric value throughout the soil column as determined by the methodology in §  250.308 (relating to soil-to-groundwater pathway numeric values), but substituting 5 micrograms per liter in groundwater for the groundwater MSC. The soil-to-groundwater pathway numeric value shall be calculated by using a concentration in soil at the site which does not produce a leachate in excess of the MSC for groundwater or by using a value which is 100 times the MSC for groundwater, expressed in milligrams per kilogram of soil. An equivalency demonstration under §  250.308(d) may be substituted for the soil-to-groundwater numeric value.

 (c)  The minimum threshold MSC in subsection (a) and the ingestion numeric value in subsection (b)(1) are calculated according to the following exposure assumption and equation: 0.50 ppb dietary intake corresponds to a 1x10^-6 risk (USFDA Threshold of Regulation Final Rule July 17, 1995) assuming the substance is a carcinogen. Correcting this value (or 5.0 ppb) to the 10^-5 risk level, in Statewide health standard formulation, the threshold of regulation concentrations are determined by the following exposure assumptions and calculations:

 Five µg/kg (substance of concern) threshold level corresponding to 1x10^-5 risk

 Dietary intake 2 kg/day x 5 µg/kg (substance - 10 µg/day (daily intake of substance of concern)

 For soil ingestion: 10 µg/100 mg soil or 100 mg/kg = Threshold concentration for soils

 For groundwater ingestion: 10 µg/2L water = 5 µg/L - Threshold concentration for water

 (a)  In addition to any protection afforded under other requirements for meeting surface water and air quality standards and MSCs under this chapter, based on the screening process in this section, direct impacts from regulated substances to the following receptors shall be assessed and addressed to implement a remedy that is protective of the environment:

   (1)  Individuals of threatened or endangered species as designated by the United States Fish and Wildlife Service under the Endangered Species Act (16 U.S.C.A. § §  1531—1544).

   (2)  Exceptional value wetlands as defined in §  105.17 (relating to wetlands).

   (3)  Habitats of concern.

   (4)  Species of concern.

 (b)  For purposes of determining impacts on ecological receptors, no additional evaluation is required if the remediation attains a level equal to 1/10th of the value in Appendix A, Tables 3 and 4, except for constituents of potential ecological concern identified in Table 8, or if the criteria in paragraph (1), (2) or (3) are met. Information that supports a determination that no additional evaluation is required shall be documented in the final report.

   (1)  Jet fuel, gasoline, kerosene, number two fuel oil or diesel fuel are the only constituents detected onsite.

   (2)  The area of contaminated soil is less than 2 acres and the area of contaminated sediment is less than 1,000 square feet.

   (3)  The site has features, such as buildings, parking lots or graveled paved areas, which would obviously eliminate the specific exposure pathways, such as soils exposure.

 (c)  If none of the criteria in subsection (b) are met and if no Constituents of Potential Ecological Concern (CPECs) associated with the release being addressed as part of an NIR at the site, as identified in Appendix A, Table 8, are detected onsite, an onsite evaluation shall be conducted to document any indications of ecological impact. Ecological impacts requiring more detailed evaluation exist if there are differences of greater than 50% in the density or diversity of species or habitats of concern when compared with nearby reference areas representing equivalent ecological areas without contamination, if available. This evaluation shall also document the presence of threatened and endangered species and exceptional value wetlands. If no ecological impacts requiring further evaluation are identified, and no threatened and endangered species exist within a 2,500-foot radius of the site and no exceptional value wetlands exist on the site, no further evaluation is required and that determination shall be documented in the final report.

 (d)  If none of the criteria in subsection (b) are met and if CPECs associated with the release being addressed as part of an NIR at the site are detected onsite or ecological impacts requiring more detailed evaluation, threatened and endangered species, or exceptional value wetlands as identified in subsection (c) exist, a detailed onsite evaluation shall be conducted by a person qualified to perform environmental risk assessments to document any substantial ecological impacts. Substantial ecological impacts exist if there are differences of greater than 20% in the density of species of concern or greater than 50% in the diversity and extent of habitats of concern when compared with nearby reference areas representing equivalent ecological areas without contamination, if available. If there are no substantial ecological impacts identified and there are no threatened or endangered species on or within a 2,500-foot radius of the site and no exceptional value wetlands on the site, that determination shall be provided in the final report.

 (e)  If the person cannot demonstrate that they meet the criteria in subsection (b), and cannot demonstrate that the evaluation performed under subsection (c) identified no ecological impacts requiring more detailed evaluation under subsection (d), or cannot demonstrate that the evaluation performed under subsection (d) identified no substantial ecological impacts, or threatened or endangered species or exceptional value wetlands, one of the following shall be met:

   (1)  A person shall demonstrate in the final report that attainment of the Statewide health standard MSCs are protective of the ecological receptors.

   (2)  If a demonstration cannot be made that the Statewide health standard MSCs are protective of ecological receptors, a person shall demonstrate in the final report that postremedy use will eliminate complete exposure pathways at the time of the final report or in accordance with a postremediation care plan, or that mitigative measures identified in subsection (f) have been instituted and are subject to postremediation care plan requirements as described in §  250.312(b) (relating to final report).

   (3)  A person shall demonstrate attainment of the background standard.

   (4)  A person shall follow the procedures in § §  250.402(c) and 250.409 (relating to human health and environmental protection goals; and risk assessment report) and demonstrate attainment of the site-specific standard for protection of ecological receptors.

 (f)  Mitigation measures to restore or replace equivalent ecological resources in the local area of the site may be applied if the following are met:

   (1)  No exceptional value wetlands have been identified by the screening process.

   (2)  No Federal or State laws and regulations prohibit or restrict the elimination of habitats or species identified by the screening process.

   (3)  A mitigation measure is selected based on the following hierarchy:

     (i)   Restoration onsite of species and habitats identified in the screening process.

     (ii)   Replacement onsite of species and habitats identified in the screening process.

     (iii)   Replacement on an adjacent area to the site of species and habitats identified in the screening process.

     (iv)   Replacement at a location within the municipality where the site is located of species and habitats identified in the screening process.

   (4)  The Department will review and approve mitigation measures prior to implementation to ensure that the proposed remedy and intended use of the property minimize the impacts to ecological receptors identified in the screening procedure.

   (5)  The postremediation care plan requirements in §  250.312(e) or §  250.411(f) (relating to final report) are implemented.

   The provisions of this §  250.311 amended November 23, 2001, effective November 24, 2001, 31 Pa.B. 6395. Immediately preceding text appears at serial pages (233673) to (233675).

 (a)  For sites remediated under the Statewide health standard, the person conducting the remediation shall submit a final report to the Department which documents attainment of the selected standard. This final report shall include site characterization information identified in §  250.204(b)—(e) (relating to final report). The site characterization shall be conducted in accordance with scientifically recognized principles, standards and procedures. The level of detail in the investigation, and the selected methods and analyses, that may include models, shall sufficiently define the rate of movement and the present and future extent and fate of contaminants to ensure continued attainment of the remediation standard. Interpretations of geologic and hydrogeologic data shall be prepared by a professional geologist licensed in this Commonwealth.

 (b)  The final report for the Statewide health standard shall include the results of the evaluation of ecological receptors. If a person relies on a postremedy use to eliminate complete exposure pathways that is not implemented at the time of the final report submission, a postremediation care plan shall be submitted to document that the postremedy use is implemented within 1 year from final report approval, unless the Department approves an extension of time. If mitigation measures are implemented under §  250.311 (relating to evaluation of ecological receptors), a postremediation care plan shall be documented in the final report that includes the following:

   (1)  A plan to maintain the mitigated ecological resource.

   (2)  Reporting of the ongoing success or failure of the mitigation measure implemented.

   (3)  Mitigation measures, instituted at the time of the final report, shall be successfully accomplished and sustained up to 5 years from final report approval.

 (c)  Final reports for the Statewide health standard shall include information on the basis for selecting residential or nonresidential standards and the additional information identified in §  250.204(f)(1)—(5).

 (d)  The final report for the Statewide health standard shall include all sampling data and descriptions of the sampling methodology and analytical results, including the appropriate statistical methodologies, which pertain to whether the remediation has attained the selected standard, following the requirements of Subchapter G (relating to demonstration of attainment).

 (e)  If engineering controls are needed to attain or maintain a standard, if institutional controls are needed to maintain a standard, if the fate and transport analysis indicates that the remediation standard, including the solubility limitation in §  250.304(b) (relating to MSCs for groundwater), may be exceeded at the point of compliance in the future, or if the remediation relies on natural attenuation, a postremediation care plan shall be documented in the final report that includes the information identified in §  250.204(g).

 (f)  If the soil to groundwater pathway soil buffer distances are used, as identified in §  250.308 (relating to soil-to-groundwater pathway numeric values), the following information shall be included in the final report:

   (1)  Information demonstrating that the actual site soil column thickness below the contaminated soil by the information gathered from soil sample borings conducted during the site characterization is at least the thickness identified in Appendix A, Tables 3 and 4.

   (2)  Information gathered during the field investigation phase and the laboratory analyses conducted on the soil samples.

   (3)  The boring logs and all other data presented in appropriate maps, cross sections, figures and tables.

 (g)  If an equivalency demonstration is used under §  250.308(d), the following information shall be included in the final report:

   (1)  Information describing the actual site soil column below the contaminated soil determined by soil sample borings conducted during the site characterization.

   (2)  Information gathered during the field investigation phase and the laboratory analyses conducted on the groundwater samples beneath the contaminated soil.

   (3)  The boring logs and all other data presented in appropriate maps, cross sections, figures and tables.

   (4)  Sampling data, in a tabular format, that shows no exceedances of groundwater MSCs or the background standard, under §  250.308(d)(2).

   (5)  A demonstration, submitted in a graphic format, that sampling data indicates no increasing trend of concentration over time that may exceed the standard.

 (h)  When a person implements a remedy that relies on access to properties owned by third parties, for remediation or monitoring, documentation of cooperation or agreement shall be submitted as part of the final report.

   This section cited in 25 Pa. Code §  245.313 (relating to remedial action completion report); and 25 Pa. Code §  250.311 (relating to evaluation of ecological receptors).

Subchapter D. SITE-SPECIFIC STANDARD

Sec.

 (a)  This subchapter sets forth requirements and procedures for any person selecting the site-specific standards.

 (a)  Site-specific standards shall be developed that meet the human health and environmental protection goals specified in this section. The development of site-specific standards shall be based on a site-specific risk assessment, if required.

 (b)  The site-specific standard shall be a protective level that eliminates or reduces any risk to human health in accordance with the following:

   (1)  For known or suspected carcinogens, soil and groundwater cleanup standards shall be established at exposures which represent an excess upperbound lifetime risk of between 1 in 10,000 and 1 in 1 million. The cumulative excess risk to exposed populations, including sensitive subgroups, may not be greater than 1 in 10,000.

   (2)  For systemic toxicants, soil and groundwater cleanup standards shall represent the level to which the human population could be exposed on a daily basis without appreciable risk of deleterious effect to the exposed population. Where several systemic toxicants affect the same target organ or act by the same method of toxicity, the hazard index may not exceed one.

 (c)  In addition to any protection afforded under other requirements for meeting surface water and air quality standards under this chapter, direct impacts resulting from a release of regulated substances to the receptors identified in §  250.311(a) (relating to evaluation of ecological receptors) shall be assessed and addressed in the remedial investigation, risk assessment and cleanup plans.

 (d)  If a person is using the site-specific standard to protect ecological receptors under this subchapter or in accordance with §  250.311(e), the following shall be performed:

   (1)  An ecological risk assessment to determine if an impact has occurred or will occur if the release of a regulated substance goes unabated.

   (2)  An ecological risk assessment conducted in accordance with Department-approved EPA or ASTM guidance to establish acceptable remediation levels or alternative remedies based on current and future use that are protective of the ecological receptors.

   (3)  Implementation of the selected remedy, which may include mitigation measures under §  230.311(f), that is protective of the ecological receptors.

 (a)  Groundwater will not be considered a current or potential source of drinking water where groundwater has a background total dissolved solids concentration greater than 2,500 milligrams per liter.

 (b)  Except as provided in subsection (a), current and probable future use of groundwater shall be determined on a site-specific basis.

 (c)  Drinking water use of groundwater shall be made suitable by at least meeting the primary and secondary MCLs at all points of exposure identified in §  250.404 (relating to pathway identification and elimination).

 (a)  The person shall use Department-approved EPA or ASTM guidance to identify any potential current and future exposure pathways for both human receptors and environmental receptors identified in §  250.402 (relating to human health and environmental protection goals).

 (b)  The person shall summarize pathways for current land use and any probable future land use separately in the site-specific remedial investigation report.

 (c)  If no exposure pathway exists, and no remedy is required to be proposed and completed, the following apply:

   (1)  The remedial investigation report shall contain information necessary to determine that no current or future exposure pathway exists.

   (2)  A risk assessment, including an ecological risk assessment, and cleanup plan are not required.

   (3)  The remedial investigation report and the final report may be submitted simultaneously.

 (d)  Prior to performing a risk assessment as required in §  250.405 (relating to when to perform a risk assessment), the person may take into account the effect of engineering and institutional controls in eliminating pathways identified in subsection (b) and include this evaluation in the remedial investigation report.

 (a)  Except as specified in subsections (b) and (c), a person who remediates under this subchapter shall develop site-specific standards based on a risk assessment. The person shall conduct the risk assessment according to the procedures specified in Subchapter F (relating to exposure and risk determinations).

 (b)  The risk assessment report is not required if a fate and transport analysis which takes into account the effects of engineering and institutional controls demonstrates that neither present nor future exposure pathways exist. This demonstration shall follow the procedures described in §  250.404 (relating to pathway identification and elimination).

 (c)  The baselin