ILLINOIS POLLUTION CONTROL BOARD
    July 27, 2000
    IN THE MATTER OF:
    PROPOSED AMENDMENTS TO TIERED
    APPROACH TO CORRECTIVE ACTION
    OBJECTIVES (TACO) (35 ILL. ADM. CODE
    742)
    )
    )
    )
    )
    )
    )
    R00-19(B)
    (Rulemaking – Land)
    Proposed Rule. First Notice.
    OPINION AND ORDER OF THE BOARD (by E.Z. Kezelis, M. McFawn, N.J. Melas):
    On May 15, 2000, the Illinois Environmental Protection Agency (Agency) filed a proposal
    to amend 35 Ill. Adm. Code 742 of the Board’s land regulations, which are commonly referred to
    as the TACO rules. The TACO rules were originally adopted by the Board on June 5, 1997, in
    In
    re
    Tiered Approach to Corrective Action Objectives (TACO): 35 Ill. Adm. Code 742, R97-
    12(A). Part 742 contains procedures for developing remediation objectives based on risks to
    human health and the environment posed by environmental conditions at sites undergoing
    remediation in the Site Remediation Program, the Leaking Underground Storage Tank Program,
    and pursuant to RCRA Part B permits and closures.
    The Board accepted the Agency’s proposal for hearing on May 18, 2000. The Agency
    submitted these proposed amendments to address several aspects of TACO that, with the benefit of
    time and practical experience, it believes are in need of clarification and correction. Statement of
    Reasons at page 2. The Agency also proposes the adoption of a new legal instrument called the
    “Environmental Land Use Control” (ELUC). The adoption by the Board of these amendments is
    authorized pursuant to Sections 27 and 28 of the Environmental Protection Act (Act) (415 ILCS
    5/27, 28 (1998)). Today the Board sends this regulatory proposal to first notice under the
    Administrative Procedures Act without commenting on the merits of the proposed rules. 5 ILCS
    100/1-1
    et seq
    . (1998).
    To facilitate an expedited rulemaking, the Board also separates the proposed amendments
    into two subdockets, subdockets A and B. The proposed amendments contained in subdocket A
    are subject to a statutory adoption deadline. Those proposed rules pertain to the ELUCs and they
    must be adopted as final rules no later than January 6, 2001. See Pub. Act 91-0909. The stringent
    time frame necessary to meet that deadline is discussed more fully in the Board’s order in
    subdocket A that is also issued today. None of the remaining amendments contained in this
    subdocket are subject to that statutory deadline. For this reason, the Board has separated this
    rulemaking into two subdockets. In the event that it becomes necessary to move forward more
    expeditiously with the subdocket A amendments, the framework will already be in place for that to
    be accomplished.
    Both subdockets will proceed at this time to first notice and public hearing simultaneously.
    To further expedite this rulemaking, the public hearings have already been scheduled pursuant to a
    2
    hearing officer order issued on July 21, 2000. The first hearing is scheduled on August 25, 2000,
    in Chicago and the second on September 11 and 12, 2000, in Springfield. If necessary, the Board
    will hold a third hearing in Chicago on September 22, 2000.
    SUBDOCKET (B)
    Again, the Board creates two subdockets within R00-19. Subdocket A contains the rules
    proposed to Subpart J that pertain to ELUCs and elsewhere in Part 742 that pertain to institutional
    controls. This subdocket B contains all of the Agency’s proposed amendments, but for those
    pertaining to Subpart J. The Agency has stated that some of the proposed amendments are
    basically non-substantive and involve corrections to typographical errors or updates to more
    current information.
    A number of changes are also proposed throughout the appendices to Part 742. These
    involve changes in the contaminant parameters for which testing must be done under a TACO-
    based remediation. Statement of Reasons at 10. Of particular interest is the proposed adoption of
    a maximum contaminant value for methyl tertiary-butyl ether (MTBE). The Agency states that it
    proposes including the MTBE value due to the growing national concern over the increasing
    number of community water supplies that are testing positive for concentrations of MTBE.
    Statement of Reasons at 2-3.
    Additional details about the hearings and other matters will be addressed in future hearing
    officer orders as needed.
    ORDER
    The Board directs the Clerk to cause the filing of the following with the Secretary of State
    for first-notice publication in the
    Illinois Register
    .
    TITLE 35: ENVIRONMENTAL PROTECTION
    SUBTITLE G: WASTE DISPOSAL
    CHAPTER I: POLLUTION CONTROL BOARD
    SUBCHAPTER f: RISK BASED CLEANUP OBJECTIVES
    PART 742
    TIERED APPROACH TO CORRECTIVE ACTION OBJECTIVES
    SUBPART A: INTRODUCTION
    Section
    742.100
    Intent and Purpose
    742.105
    Applicability
    742.110
    Overview of Tiered Approach
    3
    742.115
    Key Elements
    742.120
    Site Characterization
    SUBPART B: GENERAL
    Section
    742.200
    Definitions
    742.205
    Severability
    742.210
    Incorporations by Reference
    742.215
    Determination of Soil Attenuation Capacity
    742.220
    Determination of Soil Saturation Limit
    742.225
    Demonstration of Compliance with Remediation Objectives
    742.230
    Agency Review and Approval
    SUBPART C: EXPOSURE ROUTE EVALUATIONS
    Section
    742.300
    Exclusion of Exposure Route
    742.305
    Contaminant Source and Free Product Determination
    742.310
    Inhalation Exposure Route
    742.315
    Soil Ingestion Exposure Route
    742.320
    Groundwater Ingestion Exposure Route
    SUBPART D: DETERMINING AREA BACKGROUND
    Section
    742.400
    Area Background
    742.405
    Determination of Area Background for Soil
    742.410
    Determination of Area Background for Groundwater
    742.415
    Use of Area Background Concentrations
    SUBPART E: TIER 1 EVALUATION
    Section
    742.500
    Tier 1 Evaluation Overview
    742.505
    Tier 1 Soil and Groundwater Remediation Objectives
    742.510
    Tier 1 Remediation Objectives Tables
    SUBPART F: TIER 2 GENERAL EVALUATION
    Section
    742.600
    Tier 2 Evaluation Overview
    742.605
    Land Use
    742.610
    Chemical and Site Properties
    4
    SUBPART G: TIER 2 SOIL EVALUATION
    Section
    742.700
    Tier 2 Soil Evaluation Overview
    742.705
    Parameters for Soil Remediation Objective Equations
    742.710
    SSL Soil Equations
    742.715
    RBCA Soil Equations
    742.720
    Chemicals with Cumulative Noncarcinogenic Effects
    SUBPART H: TIER 2 GROUNDWATER EVALUATION
    Section
    742.800
    Tier 2 Groundwater Evaluation Overview
    742.805
    Tier 2 Groundwater Remediation Objectives
    742.810
    Calculations to Predict Impacts from Remaining Groundwater Contamination
    SUBPART I: TIER 3 EVALUATION
    Section
    742.900
    Tier 3 Evaluation Overview
    742.905
    Modifications of Parameters
    742.910
    Alternative Models
    742.915
    Formal Risk Assessments
    742.920
    Impractical Remediation
    742.925
    Exposure Routes
    742.930
    Derivation of Toxicological Data
    SUBPART J: INSTITUTIONAL CONTROLS
    Section
    742.1000
    Institutional Controls
    742.1005
    No Further Remediation Letters
    742.1010
    Restrictive Covenants, Deed Restrictions and Negative Easements
    742.1015
    Ordinances
    742.1020
    Highway Authority Agreements
    SUBPART K: ENGINEERED BARRIERS
    Section
    742.1100
    Engineered Barriers
    742.1105
    Engineered Barrier Requirements
    APPENDIX A
    General
    ILLUSTRATION A
    Developing Soil Remediation Objectives Under the Tiered Approach
    5
    ILLUSTRATION B
    Developing Groundwater Remediation Objectives Under the Tiered
    Approach
    TABLE A
    Soil Saturation Limits (C
    sat
    ) for Chemicals Whose Melting Point is Less than 30
    °
    C
    TABLE B
    Tolerance Factor (K)
    TABLE C
    Coefficients {A
    N-I+1
    } for W Test of Normality, for N=2(1)50
    TABLE D
    Percentage Points of the W Test for N=3(1)50
    TABLE E
    Similar-Acting Noncarcinogenic Chemicals
    TABLE F
    Similar-Acting Carcinogenic Chemicals
    TABLE G
    Concentrations of Inorganic Chemicals in Background Soils
    TABLE H
    Chemicals Whose Tier 1 Class I Groundwater Remediation Objective Exceeds
    the 1 in 1,000,000 Cancer Risk Concentration
    APPENDIX B
    Tier 1 Tables and Illustrations
    ILLUSTRATION A
    Tier 1 Evaluation
    TABLE A
    Tier 1 Soil Remediation Objectives for Residential Properties
    TABLE B
    Tier 1 Soil Remediation Objectives for Industrial/Commercial Properties
    TABLE C
    pH Specific Soil Remediation Objectives for Inorganics and Ionizing Organics
    for the Soil Component of the Groundwater Ingestion Route (Class I
    Groundwater)
    TABLE D
    pH Specific Soil Remediation Objectives for Inorganics and Ionizing Organics
    for the Soil Component of the Groundwater Ingestion Route (Class II
    Groundwater)
    TABLE E
    Tier 1 Groundwater Remediation Objectives for the Groundwater Component of
    the Groundwater Ingestion Route
    TABLE F
    Values Used to Calculate the Tier 1 Soil Remediation Objectives for the Soil
    Component of the Groundwater Ingestion Route
    APPENDIX C
    Tier 2 Tables and Illustrations
    ILLUSTRATION A
    Tier 2 Evaluation for Soil
    ILLUSTRATION B
    Tier 2 Evaluation for Groundwater
    ILLUSTRATION C
    US Department of Agriculture Soil Texture Classification
    TABLE A
    SSL Equations
    TABLE B
    SSL Parameters
    TABLE C
    RBCA Equations
    TABLE D
    RBCA Parameters
    TABLE E
    Default Physical and Chemical Parameters
    TABLE F
    Methods for Determining Physical Soil Parameters
    TABLE G
    Error Function (erf)
    TABLE H
    Q/C Values By Source Area
    TABLE I
    K
    [oc]
    Values for Ionizing Organics as a Function of pH (cm
    3
    /g or L/kg)
    TABLE J
    Values to be Substituted for k
    s
    when Evaluating Inorganics as a Function of pH
    (cm
    3
    [water]/g
    [soil]
    )
    TABLE K
    Parameter Estimates for Calculating Water-Filled Soil Porosity (
    θ
    w
    )
    6
    AUTHORITY: Implementing Sections 22.4, 22.12, Title XVI, and Title XVII and authorized by
    Sections 27, 57.14, and 58.5 of the Environmental Protection Act [415 ILCS 5/22.4, 22.12, 27,
    57.14 and 58.5 and Title XVI and Title XVII].
    SOURCE: Adopted in R97-12(A) at 21 Ill. Reg. 7942, effective July 1, 1997; amended in R97-
    12(B) at 21 Ill. Reg. 16391, effective December 8, 1997; amended in R97-12(C) at 22 Ill. Reg.
    10847, effective June 8, 1998; amended in R00-19(B) at 24 Ill. Reg. _______, effective
    ____________________.
    NOTE:
    Capitalization indicates statutory language.
    SUBPART B: GENERAL
    Section 742.210
    Incorporations by Reference
    a)
    The Board incorporates the following material by reference:
    ASTM. American Society for Testing and Materials, 1916 Race Street,
    Philadelphia, PA 19103 (215) 299-5400
    ASTM D 2974-87, Standard Test Methods for Moisture, Ash and Organic
    Matter of Peat and Other Organic Soils, approved May 29, 1987
    (reapproved 1995).
    ASTM D 2488-93, Standard Practice for Description and Identification of
    Soils (Visual-Manual Procedure), approved September 15, 1993.
    ASTM D 1556-90, Standard Test Method for Density and Unit Weight of
    Soil in Place by the Sand-Cone Method, approved June 29, 1990.
    ASTM D 2167-94, Standard Test Method for Density and Unit Weight of
    Soil in Place by the Rubber Balloon Method, approved March 15, 1994.
    ASTM D 2922-91, Standard Test Methods for Density of Soil and Soil-
    Aggregate in Place by Nuclear Methods (Shallow Depth), approved
    December 23, 1991.
    ASTM D 2937-94, Standard Test Method for Density of Soil in Place by
    the Drive-Cylinder Method, approved June 15, 1994.
    ASTM D 854-92, Standard Test Method for Specific Gravity of Soils,
    approved November 15, 1992.
    ASTM D 2216-92, Standard Method for Laboratory Determination of
    Water (Moisture) Content of Soil and Rock, approved June 15, 1992.
    7
    ASTM D 4959-89, Standard Test Method for Determination of Water
    (Moisture) Content of Soil by Direct Heating Method, approved June 30,
    1989 (reapproved 1994).
    ASTM D 4643-93, Standard Test Method for Determination of Water
    (Moisture) Content of Soil by the Microwave Oven Method, approved July
    15, 1993.
    ASTM D 5084-90, Standard Test Method for Measurement of Hydraulic
    Conductivity of Saturated Porous Materials Using a Flexible Wall
    Permeameter, approved June 29, 1990.
    ASTM D 422-63, Standard Test Method for Particle-Size Analysis of
    Soils, approved November 21, 1963 (reapproved 1990).
    ASTM D 1140-92, Standard Test Method for Amount of Material in Soils
    Finer than the No. 200 (75
    μ
    m) Sieve, approved November 15, 1992.
    ASTM D 3017-88, Standard Test Method for Water Content of Soil and
    Rock in Place by Nuclear Methods (Shallow Depth), approved May 27,
    1988.
    ASTM D 4525-90, Standard Test Method for Permeability of Rocks by
    Flowing Air, approved May 25, 1990.
    ASTM D 2487-93, Standard Test Method for Classification of Soils for
    Engineering Purposes, approved September 15, 1993.
    ASTM E 1527-93, Standard Practice for Environmental Site Assessments:
    Phase I Environmental Site Assessment Process, approved March 15, 1993.
    Vol. 11.04.
    ASTM E 1739-95, Standard Guide for Risk-Based Corrective Action
    Applied at Petroleum Release Sites, approved September 10, 1995.
    Barnes, Donald G. and Dourson, Michael. (1988). Reference Dose (RfD):
    Description and Use in Health Risk Assessments. Regulatory Toxicology and
    Pharmacology. 8, 471-486.
    GPO. Superintendent of Documents, U.S. Government Printing Office, Washington,
    DC 20401, (202) 783-3238.
    USEPA Guidelines for Carcinogenic Risk Assessment, 51 Fed. Reg.
    33992-34003 (September 24, 1986).
    "Test Methods for Evaluating Solid Waste, Physical/Chemical Methods",
    USEPA Publication number SW-846 (Third Edition, Final Update III,
    8
    December 1996), as amended by Updates I, IIA, and III (Document No.
    955-001-00000-1)(contact USEPA, Office of Solid Waste, for Update III).
    "Methods for the Determination of Organic Compounds in Drinking Water",
    EPA Publication No. EPA/600/4-88/039 (December 1988 (Revised July
    1991)).
    "Methods for the Determination of Organic Compounds in Drinking Water,
    Supplement II", EPA Publication No. EPA/600/R-92/129 (August 1992).
    "Methods for the Determination of Organic Compounds in Drinking Water,
    Supplement III", EPA Publication No. EPA/600/R-95/131 (August 1995).
    IRIS. Integrated Risk Information System, National Center for Environmental
    Assessment, U.S. Environmental Protection Agency, 26 West Martin Luther King
    Drive, MS-190, Cincinnati, OH 45268, (513) 569-7254.
    "Reference Dose (RfD): Description and Use in Health Risk Assessments",
    Background Document 1A (March 15, 1993).
    "EPA Approach for Assessing the Risks Associated with Chronic
    Exposures to Carcinogens", Background Document 2 (January 17, 1992).
    Nelson, D.W., and L.E. Sommers. 1982. Total carbon, organic carbon, and
    organic matter. In: A.L. Page (ed.), Methods of Soil Analysis. Part 2. Chemical
    and Microbiological Properties. 2nd Edition, pp. 539-579, American Society of
    Agronomy. Madison, WI.
    NTIS. National Technical Information Service, 5285 Port Royal Road,
    Springfield, VA 22161, (703) 487-4600.
    "Dermal Exposure Assessment: Principles and Applications", EPA
    Publication No. EPA/600/8-91/011B (January 1992).
    "Exposure Factors Handbook", EPA Publication No. EPA/600/8-89/043
    (July 1989).
    "Risk Assessment Guidance for Superfund, Vol. I; Human Health
    Evaluation Manual, Supplemental Guidance: Standard Default Exposure
    Factors", OSWER Directive 9285.6-03 (March 1991).
    "Rapid Assessment of Exposure to Particulate Emissions from Surface
    Contamination Sites," EPA Publication No. EPA/600/8-85/002 (February
    1985), PB 85-192219.
    "Risk Assessment Guidance for Superfund, Volume I; Human Health
    Evaluation Manual (Part A)", Interim Final, EPA Publication No.
    EPA/540/1-89/002 (December 1989).
    9
    "Risk Assessment Guidance for Superfund, Volume I; Human Health
    Evaluation Manual, Supplemental Guidance, Dermal Risk Assessment
    Interim Guidance", Draft (August 18, 1992).
    "Soil Screening Guidance: Technical Background Document", EPA
    Publication No. EPA/540/R-95/128, PB96-963502 (May 1996).
    "Soil Screening Guidance: User's Guide", EPA Publication No.
    EPA/540/R-96/018, PB96-963505 (April 1996).
    "
    Superfund Exposure Assessment Manual", EPA Publication No.
    EPA/540/1-88/001 (April 1988).
    RCRA Facility Investigation Guidance, Interim Final, developed by USEPA (EPA
    530/SW-89-031), 4 volumes May 1989.
    b)
    CFR (Code of Federal Regulations). Available from the Superintendent of
    Documents, U.S. Government Printing Office, Washington, D.C. 20402 (202)783-
    3238:
    40 CFR 761.120 (19931998).
    c)
    This Section incorporates no later editions or amendments.
    (Source: Amended in R00-19(B) at 24 Ill. Reg. _______ , effective _____________)
    Section 742.220
    Determination of Soil Saturation Limit
    a)
    For any organic contaminant that has a melting point below 30
    o
    C, the remediation
    objective for the inhalation exposure route developed under Tier 2 or Tier 3 shall
    not exceed the soil saturation limit, as determined under subsection (c) of this
    Section.
    b)
    For any organic contaminant, the remediation objective under Tier 2 or Tier 3 for
    the soil component of the groundwater ingestion exposure route shall not exceed the
    soil saturation limit, as determined under subsection (c) of this Section.
    c)
    The soil saturation limit shall be:
    1)
    The value listed in Appendix A, Table A for that specific contaminant;
    2)
    A value derived from Equation S29 in Appendix C, Table A; or
    3)
     
    A value derived from another method approved by the
    Agency.
    (Source: Amended in R00-19(B) at 24 Ill. Reg. _______, effective ______________)
    10
    Section 742.225
    Demonstration of Compliance with Remediation Objectives
    Compliance is achieved if each sample result does not exceed that respective remediation
    objective unless a person elects to proceed under subsections (c), (d) and (e) of this Section.
    a)
    Compliance with groundwater remediation objectives developed under Subparts D
    through F and H through I shall be demonstrated by comparing the contaminant
    concentrations of discrete samples at each sample point to the applicable
    groundwater remediation objective. Sample points shall be determined by the
    program under which remediation is performed.
    b)
    Unless the person elects to composite samples or average sampling results as
    provided in subsections (c) and (d) of this Section, compliance with soil
    remediation objectives developed under Subparts D through G and I shall be
    demonstrated by comparing the contaminant concentrations of discrete samples to
    the applicable soil remediation objective.
    1)
    Except as provided in subsections (c) and (d) of this Section, compositing
    of samples is not allowed.
    2)
    Except as provided in subsections (c) and (d) of this Section, averaging of
    sample results is not allowed.
    3)
    Notwithstanding subsections (c) and (d) of this Section, compositing of
    samples and averaging of sample results is not allowed for the construction
    worker population.
    4)
    The number of sampling points required to demonstrate compliance is
    determined by the requirements applicable to the program under which
    remediation is performed.
    c)
    If a person chooses to composite soil samples or average soil sample results to
    demonstrate compliance relative to the soil component of the groundwater ingestion
    exposure route, the following requirements apply:
    1)
    A minimum of two sampling locations for every 0.5 acre of contaminated
    area is required, with discrete samples at each sample location obtained at
    every two feet of depth, beginning at six inches below the ground surface
    and continuing through the zone of contamination. Alternatively, a sampling
    method may be approved by the Agency based on an appropriately designed
    site-specific evaluation. Samples obtained at or below the water table
    shall not be used in compositing or averaging.
    2)
    For contaminants of concern other than volatile organic contaminants:
    A)
    Discrete samples from the same boring may be composited.
    B)
    Discrete sample results from the same boring may be averaged.
    11
    3)
    For volatile organic contaminants:
    A)
    Compositing of samples is not allowed.
    B)
    Discrete sample results from the same boring may be averaged.
    d)
    If a person chooses to composite soil samples or average soil sample results to
    demonstrate compliance relative to the inhalation exposure route or ingestion
    exposure route, the following requirements apply:
    1)
    A person shall submit a sampling plan for Agency approval, based upon a
    site-specific evaluation;
    2)
    For volatile organic compounds, compositing of samples is not allowed;
    and
    3)
    All samples shall be collected within the contaminated area.
    e)
     
    When averaging under this Section, if no more than 50% of sample results are
    reported as "non-detect", "no contamination", "below detection limits", or similar
    terms, such results shall be included in the averaging calculation as one-half of the
    reported analytical detection limit for the contaminant. However, when performing
    a test for normal or lognormal distribution for the purpose of calculating a 95%
    Upper Confidence Limit of the mean for a contaminant, a person may substitute for
    each non-detect value a randomly generated value between, but not including, zero
    and the reported analytical detection limit. If more than 50% of sample results are
    "non-detect", another statistically valid procedure approved by the Agency may be
    used to determine an average.
    f)
    All soil samples collected after the effective date of this subsection (f) shall be
    reported on a dry weight basis for the purpose of demonstrating compliance, with
    the exception of the TCLP and SPLP and the property pH.
    (Source: Amended in R00-19(B) at 24 Ill. Reg. _______, effective ____________)
    SUBPART C: EXPOSURE ROUTE EVALUATIONS
    Section 742.300
    Exclusion of Exposure Route
    a)
    This Subpart sets forth requirements to demonstrate that an actual or potential
    impact to a receptor or potential receptor from a contaminant of concern can be
    excluded from consideration from one or more exposure routes. If an evaluation
    under this Part Subpart demonstrates the applicable requirements for excluding an
    exposure route are met, then the exposure route is excluded from consideration and
    no remediation objective(s) need be developed for that exposure route.
    b)
     
    No exposure route may be excluded from consideration until characterization of
    the extent and concentrations of contaminants of concern at a site has been
    12
    performed. The actual steps and methods taken to characterize a site shall be
    determined by the specific program requirements under which the site remediation
    is being addressed.
    c)
     
    As an alternative to the use of the requirements in this Part Subpart, a person
    may use the procedures for evaluation of exposure routes under Tier 3 as set forth
    in Section 742.925.
    (Source: Amended in R00-19(B) at 24 Ill. Reg. _______, effective ______________)
    Section 742.305
    Contaminant Source and Free Product Determination
    No exposure route shall be excluded from consideration relative to a contaminant of concern
    unless the following requirements are met:
    a)
    The sum of the concentrations of all organic contaminants of concern shall not
    exceed the attenuation capacity of the soil as determined under Section 742.215;
    b)
    The concentrations of any organic contaminants of concern remaining in the soil
    shall not exceed the soil saturation limit as determined under Section 742.220;
    c)
    Any soil which contains contaminants of concern shall not exhibit any of the
    characteristics of reactivity for hazardous waste as determined under 35 Ill. Adm.
    Code 721.123;
    d)
    Any soil which contains contaminants of concern shall not exhibit a pH less than or
    equal to 2.0 or greater than or equal to 12.5, as determined by SW-846 Method
    9040B: pH Electrometric for soils with 20% or greater aqueous (moisture) content
    or by SW-846 Method 9045C: Soil pH for soils with less than 20% aqueous
    (moisture) content as incorporated by reference in Section 742.210; and
    e)
     
    Any soil which contains contaminants of concern in the following list of inorganic
    chemicals or their salts shall not exhibit any of the characteristics of toxicity for
    hazardous waste as determined by 35 Ill. Adm. Code 721.124, or an alternative
    method approved by the Agency: arsenic, barium, cadmium, chromium, lead,
    mercury, selenium or silver; and.
    f)
    If contaminants of concern include polychlorinated biphenyls (PCBs), the
    concentration of any PCBs in the soil shall not exceed 50 parts per million as
    determined by SW-846 Methods.
    (Source: Amended in R00-19(B) at 24 Ill. Reg. _______, effective ______________)
    Section 742.310
    Inhalation Exposure Route
    The inhalation exposure route may be excluded from consideration if:
    a)
    The requirements of Sections 742.300 and 742.305 are met; and
    13
    b)
    An institutional control, in accordance with Subpart J, is in place that meets the
    following requirements:
    1)
    Either:
    A)
    The concentration of any contaminant of concern within ten feet of
    the land surface or within ten feet of any man-made pathway shall
    not exceed the Tier 1 remediation objective under Subpart E for the
    inhalation exposure route; or
    B)
    An engineered barrier, as set forth in Subpart K and approved by the
    Agency, is in place; and
    2)
    Requires safety precautions for the construction worker if the Tier 1
    construction worker remediation objectives are exceeded.
    b)
    An approved engineered barrier is in place that meets the requirements of Subpart
    K;
    c)
    Safety precautions for the construction worker are taken if the Tier 1 construction
    worker remediation objectives are exceeded; and
    d)
    An institutional control, in accordance with Subpart J, will be placed on the
    property.
    (Source: Amended in R00-19(B) at 24 Ill. Reg. _______, effective ______________)
    Section 742.315
    Soil Ingestion Exposure Route
    The soil ingestion exposure route may be excluded from consideration if:
    a)
    The requirements of Sections 742.300 and 742.305 are met; and
    b)
    An institutional control, in accordance with Subpart J, is in place that meets the
    following requirements:
    1)
    Either:
    A)
    The concentration of any contaminant of concern within three feet of
    the land surface shall not exceed the Tier 1 remediation objective
    under Subpart E for the ingestion of soil exposure route; or
    B)
    An engineered barrier, as set forth in Subpart K and approved by the
    Agency, is in place; and
    2)
    Requires safety precautions for the construction worker if the Tier 1
    construction worker remediation objectives are exceeded.
    14
    b)
    An approved engineered barrier is in place that meets the requirements of Subpart
    K;
    c)
    Safety precautions for the construction worker are taken if the Tier 1 construction
    worker remediation objectives are exceeded; and
    d)
    An institutional control, in accordance with Subpart J, will be placed on the
    property.
    (Source: Amended in R00-19(B) at 24 Ill. Reg. _______, effective _______________)
    SUBPART F: TIER 2 GENERAL EVALUATION
    Section 742.605
    Land Use
    a)
    Present and post-remediation land use is evaluated in a Tier 2 evaluation.
    Acceptable exposure factors for the Tier 2 evaluation for residential,
    industrial/commercial, and construction worker populations are provided in the far
    right column of both Appendix C, both Tables B and D. Use of exposure factors
    different from those in Appendix C, Tables B and D must be approved by the
    Agency as part of a Tier 3 evaluation.
    b)
    If a Tier 2 evaluation is based on an industrial/commercial property use, then:
    1)
    Construction worker populations shall also be evaluated; and
    2)
     
    Institutional controls are required in accordance with
    Subpart J.
    (Source: Amended in R00-19(B) at 24 Ill. Reg. _______, effective _______________)
    SUBPART G: TIER 2 SOIL EVALUATION
    Section 742.700
    Tier 2 Soil Evaluation Overview
    a)
    Tier 2 remediation objectives are developed through the use of models which
    allow site-specific data to be considered. Appendix C, Tables A and C list
    equations that shall be used under a Tier 2 evaluation to calculate soil remediation
    objectives prescribed by SSL and RBCA models, respectively. (See also Appendix
    C, Illustration A.)
    b)
    Appendix C, Table A lists equations that are used under the SSL model. (See also
    Appendix C, Illustration A.) The SSL model has equations to evaluate the
    following human exposure routes:
    1)
    Soil ingestion exposure route;
    2)
    Inhalation exposure route for:
    15
    A)
    Volatiles Organic contaminants;
    B)
    Fugitive dust; and
    3)
    Soil component of the groundwater ingestion exposure route.
    c)
    Evaluation of the dermal exposure route is not required under the SSL model.
    d)
    Appendix C, Table C lists equations that are used under the RBCA model. (See
    also Appendix C, Illustration A.) The RBCA model has equations to evaluate
    human exposure based on the following:
    1)
    The combined exposure routes of inhalation of vapors and particulates, soil
    ingestion and dermal contact with soil;
    2)
    The ambient vapor inhalation (outdoor) route from subsurface soils;
    3)
    Soil component of the groundwater ingestion route; and
    4)
    Groundwater ingestion exposure route.
    e)
    The equations in either Appendix C, Table A or C may be used to calculate
    remediation objectives for each contaminant of concern under Tier 2, if the
    following requirements are met:
    1)
    The Tier 2 soil remediation objectives for the ingestion and inhalation
    exposure routes shall use the applicable equations from the same approach
    (i.e., SSL equations in Appendix C, Table C).
    2)
    The equations used to calculate soil remediation objectives for the soil
    component of the groundwater ingestion exposure route are not dependent
    on the approach utilized to calculate soil remediation objectives for the
    other exposure routes. For example, it is acceptable to use the SSL
    equations for calculating Tier 2 soil remediation objectives for the
    ingestion and inhalation exposure routes, and the RBCA equations for
    calculating Tier 2 soil remediation objectives for the soil component of the
    groundwater ingestion exposure route.
    3)
    Combining equations from Appendix C, Tables A and C to form a new
    model is not allowed. In addition, Appendix C, Tables A and C must use
    their own applicable parameters identified in Appendix C, Tables B and D,
    respectively.
    f)
    In calculating soil remediation objectives for industrial/commercial property use,
    applicable calculations shall be performed twice: once using industrial/commercial
    population default values and once using construction worker population default
    values. The more stringent soil remediation objectives derived from these
    calculations must be used for further Tier 2 evaluations.
    16
    g)
    Tier 2 data sheets provided by the Agency shall be used to present calculated Tier
    2 remediation objectives, if required by the particular program for which
    remediation is being performed.
    h)
     
    The RBCA equations which rely on the parameter Soil Water Sorption
    Coefficient (k
    s
    ) can only be used for ionizing organics and inorganics by
    substituting values for k
    s
    from Appendix C, Tables I and J, respectively. This will
    also require the determination of a site-specific value for soil pH.
    (Source: Amended in R00-19(B) at 24 Ill. Reg. _______, effective ______________)
    Section 742.710
    SSL Soil Equations
    a)
    This Section sets forth the equations and parameters used to develop Tier 2 soil
    remediation objectives for the three exposure routes using the SSL approach.
    b)
    Soil Ingestion Exposure Route
    1)
    Equations S1 through S3 form the basis for calculating Tier 2 remediation
    objectives for the soil ingestion exposure route using the SSL approach.
    Equation S1 is used to calculate soil remediation objectives for
    noncarcinogenic contaminants. Equations S2 and S3 are used to calculate
    soil remediation objectives for carcinogenic contaminants for residential
    populations and industrial/commercial and construction worker
    populations, respectively.
    2)
    For Equations S1 through S3, the SSL default values cannot be modified
    with site-specific information.
    c)
    Inhalation Exposure Route
    1)
    Equations S4 through S16, S26 and S27 are used to calculate Tier 2 soil
    remediation objectives for the inhalation exposure route using the SSL
    approach. To address this exposure route, volatiles organic contaminants
    must be evaluated separately from fugitive dust using their own equations
    set forth in subsections (c)(2) and (c)(3) of this Section, respectively.
    2)
    Volatiles Organic Contaminants
    A)
     
    Equations S4 through S10 are used to calculate Tier 2 soil
    remediation objectives for volatile organic contaminants based on
    the inhalation exposure route. Equation S4 is used to calculate soil
    remediation objectives for noncarcinogenic volatile organic
    contaminants in soil for residential and industrial/commercial
    populations. Equation S5 is used to calculate soil remediation
    objectives for noncarcinogenic volatile organic contaminants in soil
    for construction worker populations. Equation S6 is used to
    calculate soil remediation objectives for carcinogenic volatile
    17
    organic contaminants in soil for residential and
    industrial/commercial populations. Equation S7 is used to calculate
    soil remediation objectives for carcinogenic volatile organic
    contaminants in soil for construction worker populations. Equations
    S8 through S10, S27 and S28 are used for calculating numerical
    values for some of the parameters in Equations S4 through S7.
    B)
     
    For Equation S4, a numerical value for the Volatilization Factor
    (VF) can be calculated in accordance with subsection (c)(2)(F) of
    this Section. The remaining parameters in Equation S4 have either
    SSL default values listed in Appendix C, Table B or toxicological-
    specific information (i.e., RfC), which can be obtained from IRIS or
    requested from the program under which the remediation is being
    performed.
    C)
    For Equation S5, a numerical value for the Volatilization Factor
    adjusted for Agitation (VF') can be calculated in accordance with
    subsection (c)(2)(G) of this Section. The remaining parameters in
    Equation S5 have either SSL default values listed in Appendix C,
    Table B or toxicological-specific information (i.e., RfC), which can
    be obtained from IRIS or requested from the program under which
    the remediation is being performed.
    D)
    For Equation S6, a numerical value for VF can be calculated in
    accordance with subsection (c)(2)(F) of this Section. The
    remaining parameters in Equation S6 have either default values
    listed in Appendix C, Table B or toxicological-specific information
    (i.e., URF), which can be obtained from IRIS or requested from the
    program under which the remediation is being performed.
    E)
    For Equation S7, a numerical value for VF' can be calculated in
    accordance with subsection (c)(2)(G) of this Section. The
    remaining parameters in Equation S7 have either default values
    listed in Appendix C, Table B or toxicological-specific information
    (i.e., URF), which can be obtained from IRIS or requested from the
    program under which the remediation is being performed.
    F)
    The VF can be calculated for residential and industrial/commercial
    populations using one of the following equations based on the
    information known about the contaminant source and receptor
    population:
    i)
    Equation S8, in conjunction with Equation S10, is used to
    calculate VF assuming an infinite source of contamination;
    or
    18
    ii)
    If the area and depth of the contaminant source are known or
    can be estimated reliably, mass limit considerations may be
    used to calculate VF using Equation S26.
    G)
    The VF' can be calculated for the construction worker populations
    using one of the following equations based on the information
    known about the contaminant source:
    i)
    Equation S9 is used to calculate VF' assuming an infinite
    source of contamination; or
    ii)
    If the area and depth of the contaminant source are known or
    can be estimated reliably, mass limit considerations may be
    used to calculate VF' using Equation S27.
    3)
    Fugitive Dust
    A)
    Equations S11 through S16 are used to calculate Tier 2 soil
    remediation objectives using the SSL fugitive dust model for the
    inhalation exposure route. Equation S11 is used to calculate soil
    remediation objectives for noncarcinogenic contaminants in fugitive
    dust for residential and industrial/commercial populations.
    Equation S12 is used to calculate soil remediation objectives for
    noncarcinogenic contaminants in fugitive dust for construction
    worker populations. Equation S13 is used to calculate soil
    remediation objectives for carcinogenic contaminants in fugitive
    dust for residential and industrial/commercial populations.
    Equation S14 is used to calculate soil remediation objectives for
    carcinogenic contaminants in fugitive dust for construction worker
    populations. Equations S15 and S16 are used for calculating
    numerical quantities for some of the parameters in Equations S11
    through S14.
    B)
    For Equation S11, a numerical value can be calculated for the
    Particulate Emission Factor (PEF) using Equation S15. This
    equation relies on various input parameters from a variety of
    sources. The remaining parameters in Equation S11 have either
    SSL default values listed in Appendix C, Table B or toxicological-
    specific information (i.e., RfC), which can be obtained from IRIS or
    requested from the program under which the remediation is being
    performed.
    C)
    For Equation S12, a numerical value for the Particulate Emission
    Factor for Construction Worker (PEF') can be calculated using
    Equation S16. The remaining parameters in Equation S12 have
    either SSL default values listed in Appendix C, Table B or
    toxicological-specific information (i.e., RfC), which can be
    19
    obtained from IRIS or requested from the program under which the
    remediation is being performed.
    D)
    For Equation S13, a numerical value for PEF can be calculated
    using Equation S15. The remaining parameters in Equation S13
    have either default values listed in Appendix C, Table B or
    toxicological-specific information (i.e., URF), which can be
    obtained from IRIS or requested from the program under which the
    remediation is being performed.
    E)
    For Equation S14, a numerical value for PEF' can be calculated
    using Equation S16. The remaining parameters in Equation S14
    have either default values listed in Appendix C, Table B or
    toxicological-specific information (i.e., URF), which can be
    obtained from IRIS or requested from the program under which the
    remediation is being performed.
    d)
    Soil Component of the Groundwater Ingestion Exposure Route
    The Tier 2 remediation objective for the soil component of the groundwater
    ingestion exposure route can be calculated using one of the following equations
    based on the information known about the contaminant source and receptor
    population:
    1)
    Equation S17 is used to calculate the remediation objective assuming an
    infinite source of contamination.
    A)
    The numerical quantities for four parameters in Equation S17, the
    Target Soil Leachate Concentration (C
    w
    ), Soil-Water Partition
    Coefficient (K
    d
    ) for non-ionizing organics, Water-Filled Soil
    Porosity (
    θ
    w
    ) and Air-Filled Soil Porosity (
    θ
    a
    ), are calculated using
    Equations S18, S19, S20 and S21, respectively. Equations S22,
    S23, S24 and S25 are also needed to calculate numerical values for
    Equations S18 and S21. The pH-dependent K
    d
    values for ionizing
    organics can be calculated using Equation S19 and the pH-
    dependent K
    oc
    values in Appendix C, Table I.
    B)
    The remaining parameters in Equation S17 are Henry's Law
    Constant (H'), a chemical specific value listed in Appendix C,
    Table E and Dry Soil Bulk Density (
    ρ
    b
    ), a site-specific based value
    listed in Appendix C, Table B.
    C)
    The default value for GW
    obj
    is the Tier 1 groundwater objective.
    For chemicals for which there is no Tier 1 groundwater remediation
    objective, the value for GW
    obj
    shall be the Health Advisory
    concentration determined according to the procedures specified in
    35 Ill. Adm. Code 620, Subpart F. As an alternative to using Tier 1
    20
    groundwater remediation objectives or Health Advisory
    concentrations, GW
    obj
    may be developed using Equations R25 and
    R26, if approved institutional controls are in place as required in
    Subpart J.
    2)
     
    If the area and depth of the contaminant source are known or
    can be estimated reliably, mass limit considerations may be used to
    calculate the remediation objective for this exposure route using Equation
    S28. The parameters in Equation S28 have default values listed in
    Appendix C, Table B.
    (Source: Amended in R00-19(B) at 24 Ill. Reg. _______, effective ________________)
    Section 742.715
    RBCA Soil Equations
    a)
    This Section presents the RBCA model and describes the equations and parameters
    used to develop Tier 2 soil remediation objectives.
    b)
    Ingestion, Inhalation, and Dermal Contact
    1)
    The two sets of equations in subsections (b)(2) and (b)(3) of this Section
    shall be used to generate Tier 2 soil remediation objectives for the
    combined ingestion, inhalation, and dermal contact with soil exposure
    routes.
    2)
    Combined Exposure Routes of Soil Ingestion, Inhalation of Vapors and
    Particulates, and Dermal Contact with Soil
    A)
    Equations R1 and R2 form the basis for deriving Tier 2 remediation
    objectives for the set of equations that evaluates the combined
    exposure routes of soil ingestion, inhalation of vapors and
    particulates, and dermal contact with soil using the RBCA
    approach. Equation R1 is used to calculate soil remediation
    objectives for carcinogenic contaminants. Equation R2 is used to
    calculate soil remediation objectives for noncarcinogenic
    contaminants. Soil remediation objectives for the ambient vapor
    inhalation (outdoor) route from subsurface soils must also be
    calculated in accordance with the procedures outlined in subsection
    (b)(3) of this Section and compared to the values generated from
    Equations R1 or R2. The smaller value (i.e., R1 and R2 compared
    to R7 and R8, respectively) from these calculations is the Tier 2
    soil remediation objective for the combined exposure routes of soil
    ingestion, inhalation, and dermal contact with soil.
    B)
    In Equation R1, numerical values are calculated for two parameters:
    i)
    The volatilization factor for surficial soils (VF
    ss
    ) using
    Equations R3 and R4; and
    21
    ii)
    The volatilization factor for subsurface soils regarding
    particulates (VF
    p
    ) using Equation R5.
    C)
    VF
    ss
    uses Equations R3 and R4 to derive a numerical value.
    Equation R3 requires the use of Equation R6. Both equations must
    be used to calculate the VF
    ss
    . The lowest calculated value from
    these equations must be substituted into Equation R1.
    D)
    The remaining parameters in Equation R1 have either default values
    listed in Appendix C, Table D or toxicological-specific information
    (i.e., SF
    o
    , SF
    i
    ), which can be obtained from IRIS or requested from
    the program under which the remediation is being performed.
    E)
    For Equation R2, the parameters VF
    ss
    and VF
    p
    are calculated. The
    remaining parameters in Equation R2 have either default values
    listed in Appendix C, Table D or toxicological-specific information
    (i.e., RfD
    o
    , RfD
    i
    ), which can be obtained from IRIS or requested
    from the program under which the remediation is being performed.
    F)
    For chemicals other than inorganics which do not have default
    values for the dermal absorption factor (RAF
    d
    ) in Appendix C,
    Table D, a dermal absorption factor of 0.5 shall be used for
    Equations R1 and R2. For inorganics, dermal absorption may be
    disregarded (i.e., RAF
    d
    = 0).
    3)
    Ambient Vapor Inhalation (outdoor) route from Subsurface Soils (soil
    below one meter)
    A)
    Equations R7 and R8 form the basis for deriving Tier 2 remediation
    objectives for the ambient vapor inhalation (outdoor) route from
    subsurface soils using the RBCA approach. Equation R7 is used to
    calculate soil remediation objectives for carcinogenic contaminants.
    Equation R8 is used to calculate soil remediation objectives for
    noncarcinogenic contaminants.
    B)
    For Equation R7, the carcinogenic risk-based screening level for air
    (RBSL
    air
    ) and the volatilization factor for soils below one meter to
    ambient air (VF
    samb
    ) have numerical values that are calculated using
    Equations R9 and R11, respectively. Both equations rely on input
    parameters from a variety of sources.
    C)
    The noncarcinogenic risk-based screening level for air (RBSL
    air
    )
    and the volatilization factor for soils below one meter to ambient air
    (VF
    samb
    ) in Equation R8 have numerical values that can be
    calculated using Equations R10 and R11, respectively.
    c)
    Soil Component of the Groundwater Ingestion Exposure Route
    22
    1)
    Equation R12 forms the basis for deriving Tier 2 remediation objectives for
    the soil component of the groundwater ingestion exposure route using the
    RBCA approach. The parameters, groundwater at the source (GW
    source
    )
    and Leaching Factor (LF
    sw
    ), have numerical values that are calculated using
    Equations R13 and R14, respectively.
    2)
    Equation R13 requires numerical values that are calculated using Equation
    R15.
    3)
    Equation R14 requires numerical values that are calculated using Equations
    R21, R22, and R24. For non-ionizing organics, the Soil Water Sorption
    Coefficient k
    s
    shall be calculated using Equation R20. For ionizing
    organics and inorganics, the values for (k
    s
    ) are listed in Appendix C,
    Tables I and J, respectively. The pH-dependent k
    s
    values for ionizing
    organics can be calculated using Equation R20 and the pH-dependent K
    oc
    values in Appendix C, Table I. The remaining parameters in Equation R14
    are field measurements or default values listed in Appendix C, Table D.
    d)
    The default value for GW
    comp
    is the Tier 1 groundwater remediation objective. For
    chemicals for which there is no Tier 1 groundwater remediation objective, the
    value for GW
    comp
    shall be the Health Advisory concentration determined according
    to the procedures specified in 35 Ill. Adm. Code 620, Subpart F. As an alternative
    to using the Tier 1 groundwater remediation objectives or Health Advisory above
    concentrations, GW
    comp
    may be developed using Equations R25 and R26, if
    approved institutional controls are in place as may be required in Subpart J.
    (Source: Amended in R00-19(B) at 24 Ill. Reg. _______, effective _______________)
    SUBPART H: TIER 2 GROUNDWATER EVALUATION
    Section 742.805
    Tier 2 Groundwater Remediation Objectives
    a)
    To develop a groundwater remediation objective under this Section that exceeds
    the applicable Tier 1 groundwater remediation, or for which there is no Tier I
    groundwater remediation objective, a person may request approval from the
    Agency if the person has performed the following:
    1)
    Identified the horizontal and vertical extent of groundwater for which the
    Tier 2 groundwater remediation objective is sought;
    2)
    Taken corrective action, to the maximum extent practicable to remove any
    free product;
    3)
    Using Equation R26 in accordance with Section 742.810, demonstrated that
    the concentration of any contaminant of concern in groundwater will meet:
    A)
    The applicable Tier 1 groundwater remediation objective at the
    point of human exposure; or
    23
    B)
    For any contaminant of concern for which there is no Tier 1
    groundwater remediation objective, the Health Advisory
    concentration determined according to the procedures specified in
    35 Ill. Adm. Code 620, Subpart F at the point of human exposure. A
    person may request the Agency to provide these concentrations or
    may propose these concentrations under Subpart I;.
    4)
    Using Equation R26 in accordance with Section 742.810, demonstrated that
    the concentration of any contaminant of concern in groundwater within the
    minimum or designated maximum setback zone of an existing potable water
    supply well will meet the applicable Tier 1 groundwater remediation
    objective or, if there is no Tier 1 groundwater remediation objective, the
    Health Advisory concentration determined according to the procedures
    specified in 35 Ill. Adm. Code 620. A person may request the Agency to
    provide these concentrations or may propose these concentrations under
    Subpart I;
    5)
    Using Equation R26 in accordance with Section 742.810, demonstrated that
    the concentration of any contaminant of concern in groundwater discharging
    into a surface water will meet the applicable water quality standard under
    35 Ill. Adm. Code 302;
    6)
    Demonstrated that the source of the release is not located within the
    minimum or designated maximum setback zone or within a regulated
    recharge area of an existing potable water supply well; and
    7)
    If the selected corrective action includes an engineered barrier as set forth
    in Subpart K to minimize migration of contaminant of concern from the soil
    to the groundwater, demonstrated that the engineered barrier will remain in
    place for post-remediation land use through an institutional control as set
    forth in Subpart J.
    b)
    A groundwater remediation objective that exceeds the water solubility of that
    chemical (refer to Appendix C, Table E for solubility values) is not allowed.
    c)
    The contaminants of concern for which a Tier 1 remediation objective has been
    developed shall be included in any mixture of similar-acting chemicals under
    consideration in Tier 2. The evaluation of 35 Ill. Adm. Code 620.615 regarding
    mixtures of similar-acting chemicals shall be considered satisfied for Class I
    groundwater at the point of human exposure if either of the following requirements
    are achieved:
    1)
    Calculate the weighted average using the following equations:
    a
    CUOx
    a
    CUOx
    CUOx
    CUOx
    ave
    x
    x
    x
    x
    W
    +
    +
    +
    +
    =
    ...
    3
    2
    2
    1
    1
    3
    where:
    24
    Wave = Weighted Average
    x
    1
    through x
    a
    = Concentration of each individual contaminant at the location
    of concern. Note that, depending on the target organ, the actual number of
    contaminants will range from 2 to 14.
    CUOx
    a
    =
    A Tier 1 or Tier 2 remediation objective must be developed
    for each x
    a
    .
    iA)
    If the value of the weighted average calculated in accordance with
    the equations above is less than or equal to 1.0, then the remediation
    objectives are met for those chemicals.
    iiB)
    If the value of the weighted average calculated in accordance with
    the equations above is greater than 1.0, then additional remediation
    must be carried out until the level of contaminants remaining in the
    remediated area have a weighted average calculated in accordance
    with the equation above less than or equal to one; or
    2)
    Divide each individual chemical's remediation objective by the number of
    chemicals in that specific target organ group that were detected at the site.
    Each of the contaminant concentrations at the site is then compared to the
    remediation objectives that have been adjusted to account for this potential
    additivity.
    d)
    The evaluation of 35 Ill. Adm. Code 620.615 regarding mixtures of similar-acting
    chemicals are considered satisfied if the cumulative risk from any contaminant(s) of
    concern listed in Appendix A, Table H, plus any other contaminant(s) of concern
    detected in groundwater and listed in Appendix A, Table F as affecting the same
    target organ/organ system as the contaminant(s) of concern detected from Appendix
    A, Table H, does not exceed 1 in 10,000.
    (Source: Amended in R00-19(B) at 24 Ill. Reg. _______, effective _______________)
    Section 742.810
    Calculations to Predict Impacts from Remaining Groundwater
    Contamination
    a)
    Equation R26 predicts the contaminant concentration along the centerline of a
    plume emanating from a vertical planar source in the aquifer (dimensions S
    w
    wide
    and S
    d
    deep). This model accounts for both three-dimensional dispersion (x is the
    direction of groundwater flow, y is the other horizontal direction, and z is the
    vertical direction) and biodegradation.
    1)
    The parameters in this equation are:
    X =
    distance from the planar source to the location of concern,
    along the centerline of the plume (i.e., y=0, z=0)
    25
    C
    x
    =
    the concentration of the contaminant at a distance X from the
    source, along the centerline of the plume
    C
    source
    =
    the greatest potential concentration of the contaminant of
    concern in the groundwater at the source of the
    contamination, based on the concentrations of contaminants
    in groundwater due to the release and the projected
    concentration of the contaminant migrating from the soil to
    the groundwater. As indicated above, the model assumes a
    planar source discharging groundwater at a concentration
    equal to C
    source
    .
    α
    x
    =
    dispersivity in the x direction (i.e., Equation R16)
    α
    y
    =
    dispersivity in the y direction (i.e., Equation R17)
    α
    z
    =
    dispersivity in the z direction (i.e., Equation R18)
    U =
    specific discharge (i.e., actual groundwater flow velocity
    through a porous medium; takes into account the fact that the
    groundwater actually flows only through the pores of the
    subsurface materials) where the aquifer hydraulic
    conductivity (K), the hydraulic gradient (I) and the total soil
    porosity
    θ
    T
    must be known (i.e., Equation R19)
    λ
    =
    first order degradation constant obtained from Appendix C,
    Table E or from measured groundwater data
    S
    w
    =
    width of planar groundwater source in the y direction
    S
    d
    =
    depth of planar groundwater source in the z direction
    2)
    The following parameters are determined through field measurements: U, K,
    I,
    θ
    T
    , S
    w
    , S
    d
    .
    A)
    The determination of values for U, K, I and
    θ
    T
    can be obtained
    through the appropriate laboratory and field techniques;
    B)
    From the immediate down-gradient edge of the source of the
    groundwater contamination values for S
    w
    and S
    d
    shall be
    determined. S
    w
    is defined as the width of groundwater at the source
    which exceeds the Tier 1 groundwater remediation objective. S
    d
    is
    defined as the depth of groundwater at the source which exceeds the
    Tier 1 groundwater remediation objective; and
    C)
    Total soil porosity can also be calculated using Equation R23.
    26
    b)
    Once values are obtained for all the input parameters identified in subsection (a) of
    this Section, the contaminant concentration along the centerline of the plume at a
    distance X from the source shall be calculated such so that that the distance from
    the down-gradient edge of the source of the contamination at the site to the point
    where the contaminant concentration is equal to the Tier 1 groundwater remediation
    objective or Health Advisory concentration.
    1)
    If there are any potable water supply wells located within the calculated
    distance X, then the Tier 1 groundwater remediation objective or Health
    Advisory concentration shall be met at the edge of the minimum or
    designated maximum setback zone of the nearest potable water supply
    down-gradient of the source. If no potable water supply wells exist within
    the calculated distance X, then it can be determined that no existing potable
    water supply wells are adversely impacted. To demonstrate that a
    minimum or maximum setback zone of a potable water supply well will not
    be impacted above the applicable Tier 1 groundwater remediation
    objective, X shall be the distance from the C
    source
    location to the edge of the
    setback zone.
    2)
     
    To demonstrate that no surface water is adversely impacted, X shall be the
    distance from the down-gradient edge of the source of the contamination at
    the site to the nearest surface water body. This calculation must show that
    the contaminant in the groundwater at this location (C
    x
    ) does not exceed the
    applicable water quality standard.
    (Source: Amended in R00-19(B) at 24 Ill. Reg. _______, effective ______________)
    SUBPART I: TIER 3 EVALUATION
    Section 742.900
    Tier 3 Evaluation Overview
    a)
    Tier 3 sets forth a flexible framework to develop remediation objectives outside of
    the requirements of Tiers 1 and 2. Although Tier 1 and Tier 2 evaluations are not
    prerequisites to conduct Tier 3 evaluations, data from Tier 1 and Tier 2 can assist
    in developing remediation objectives under a Tier 3 evaluation.
    b)
    The levels of detail required to adequately characterize a site depends on the
    particular use of Tier 3. Tier 3 can require additional investigative efforts beyond
    those described in Tier 2 to characterize the physical setting of the site. However,
    in situations where remedial efforts have simply reached a physical obstruction
    additional investigation may not be necessary for a Tier 3 submittal.
    c)
    Situations that can be considered for a Tier 3 evaluation include, but are not limited
    to:
    1)
    Modification of parameters not allowed under Tier 2;
    2)
    Use of models different from those used in Tier 2;
    27
    3)
    Use of additional site data to improve or confirm predictions of exposed
    receptors to contaminants of concern;
    4)
    Analysis of site-specific risks using formal risk assessment, probabilistic
    data analysis, and sophisticated fate and transport models (e.g., requesting a
    target hazard quotient greater than 1 or a target cancer risk greater than 1 in
    1,000,000);
    5)
    Requests for site-specific remediation objectives because an assessment
    indicates further remediation is not practical;
    6)
    Incomplete human exposure pathway(s) not excluded under Subpart C;
    7)
    Use of toxicological-specific information not available from the sources
    listed in Tier 2:;
    8)
    Land uses which are substantially different from the assumed residential or
    industrial/commercial property uses of a site (e.g., a site will be used for
    recreation in the future and cannot be evaluated in Tiers 1 or 2); and
    9)
    Requests for site-specific remediation objectives which exceed Tier 1
    groundwater remediation objectives so long as the following is
    demonstrated:
    A)
    TO THE EXTENT PRACTICAL, THE EXCEEDANCE OF THE
    GROUNDWATER QUALITY STANDARD HAS BEEN
    MINIMIZED AND BENEFICIAL USE APPORPRIATE TO THE
    GROUNDWATER THAT WAS IMPACTED HAS BEEN
    RETURNED; AND
    To the extent practical, the exceedance of the
    groundwater quality standard has been minimized and beneficial
    use appropriate to the groundwater that was impacted has been
    returned; and
    B)
    ANY THREAT TO HUMAN HEALTH OR THE ENVIRONMENT
    HAS BEEN MINIMIZED.
    Any threat to human health or the
    environment has been minimized
    . (Section 58.5(D)(4)(A) of the
    Act)[415 ILCS 5/58.5(D)(4)(A)]
    d)
    For requests of a target cancer risk ranging between 1 in 1,000,000 and 1 in 10,000
    at the point of human exposure or a target hazard quotient greater than 1 at the point
    of human exposure, the requirements of Section 742.915 shall be followed.
    Requests for a target cancer risk exceeding 1 in 10,000 at the point of human
    exposure are not allowed.
    e)
    Requests for approval of a Tier 3 evaluation must be submitted to the Agency for
    review under the specific program under which remediation is performed. When
    reviewing a submittal under Tier 3, the Agency shall consider WHETHER THE
    INTERPRETATIONS AND CONCLUSIONS REACHED ARE SUPPORTED BY
    28
    THE INFORMATION GATHERED.
    whether the interpretations and conclusions
    reached are supported by the information gathered
    . (Section 58.7(e)(1) of the
    Act). [415 ILCS 58.7(e)(1)]. The Agency shall approve a Tier 3 evaluation if the
    person submits the information required under this Part and establishes through
    such information that public health is protected and that specified risks to human
    health and the environment have been minimized.
    f)
    If contaminants of concern include polychlorinated biphenyls (PCBs), requests for
    approval of a Tier 3 evaluation must additionally address the applicability of 40
    CFR 761.
    (Source: Amended in R00-19(B) at 24 Ill. Reg. _______, effective ______________)
    Section 742.925
    Exposure Routes
    Technical information may demonstrate that there is no actual or potential impact of contaminants
    of concern to receptors from a particular exposure route. In these instances, a demonstration
    excluding an exposure route shall be submitted to the Agency for review and approval. A
    submittal under this Section shall include the following information:
    a)
    A description of the route evaluated;
    b)
    Technical support including a discussion of the natural or man-made barriers to
    exposure through that route, and calculations, and modeling results A description
    of the site and physical site characteristics;
    c)
    Physical and chemical properties of contaminants of concern A discussion of the
    result and possibility of the route becoming active in the future; and
    d)
    Contaminant migration properties; Technical support that may include, but is not
    limited to, the following:
    1)
    a discussion of the natural or man-made barriers to that exposure route;
    2)
    calculations and modeling;
    3)
    physical and chemical properties of contaminants of concern; and
    4)
    contaminant migration properties.
    e)
    Description of the site and physical site characteristics; and
    f)
    Discussion of the result and possibility of the route becoming active in the future;
    (Source: Amended in R00-19(B) at 24 Ill. Reg. _______, effective ________________)
    SUBPART J: INSTITUTIONAL CONTROLS
    Section 742.1005
    No Further Remediation Letters
    29
    a)
     
    A No Further Remediation Letter issued by the Agency under 35 Ill. Adm. Code
    732 or 742 740 may be used as an institutional control under this Part if the
    requirements of subsection (b) of this Section are met.
    b)
    A request for approval of a No Further Remediation Letter as an institutional
    control shall meet the requirements applicable to the specific program under which
    the remediation is performed.
    (Source: Amended in R00-19(B) at 24 Ill. Reg. _______, effective ____________________)
    Section 742.1015
    Ordinances
    a)
    An ordinance adopted by a unit of local government that effectively prohibits the
    installation of potable water supply wells (and the use of such wells) may be used
    as an institutional control to meet the requirements of Section 742.320(d) or
    742.805(a)(3) if the requirements of this Section are met. Ordinances prohibiting
    the installation of potable water supply wells (and the use of such wells) that do not
    expressly prohibit the installation of potable water supply wells (and the use of
    such wells) by units of local government may be acceptable as institutional controls
    if the requirements of this Section are met and a Memorandum of Understanding
    (MOU) is entered into under subsection (i) of this Section.
    b)
    A request for approval of a local ordinance as an institutional control shall provide
    the following:
    1)
    A copy of the ordinance restricting groundwater use certified by an official
    of the unit of local government in which the site is located that it is the
    latest, most current a true and accurate copy of the ordinance, unless the
    Agency and the unit of local government have entered an agreement under
    subsection (i) of this Section, in which case the request may alternatively
    reference the MOU. The ordinance must demonstrate that potable use of
    groundwater from potable water supply wells is prohibited;
    2)
    A scaled map(s) delineating the areal area and extent of groundwater
    contamination (measured or modeled) above the applicable remediation
    objectives including any measured data showing concentrations of
    contaminants of concern in which the applicable remediation objectives are
    exceeded;
    3)
    Information showing the concentration of contaminants of concern in which
    the applicable remediation objectives are exceeded;
    34)
    A scaled map delineating the boundaries of all properties under which
    groundwater is located which exceeds the applicable groundwater
    remediation objectives;
    45)
    Information identifying the current owner(s) of each property identified in
    subsection (b)(4) (b)(3) of this Section; and
    30
    56)
    A copy of the proposed submission of the information to the current owners
    identified in subsection (b)(5) (b)(4) of this Section of the information
    required in subsections (b)(1) through (b)(5) (b)(4) of this Section and
    proof that the notification required in subsection (c) of this Section has been
    submitted. Within 45 days from the date the Agency's No Further
    Remediation determination is recorded, the person who requested to use the
    ordinance as an institutional control must submit proof to the Agency of the
    notice to the property owners identified in subsection (b)(4).
    c)
    Each of the property owners identified in subsection (b)(5) (b)(4) of this Section
    and the unit of local government must receive written notification from the party
    desiring to use the institutional control that groundwater remediation objectives
    have been approved by the Agency. Written proof of this notification shall be
    submitted to the Agency within 45 days from the date of the instrument
    memorializing the Agency’s no further remediation determination is recorded. The
    notification shall include:
    1)
    The name and address of the unit of local government;
    2)
    The citation to the ordinance;
    3)
    A description of the property being sent notice by adequate legal
    description or by reference to a plat showing the boundaries;
    4)
    A statement that the ordinance restricting groundwater use has been used by
    the Agency in reviewing a request for a groundwater remediation objective;
    5)
    A statement as to the nature of the release and response action with the site
    name, address, and Agency site number or Illinois inventory identification
    number; and
    6)
    A statement as to where more information may be obtained regarding the
    ordinance.
    d)
    Unless the Agency and the unit of local government have entered into a MOU under
    subsection (i) of this Section, the current owner or successors in interest of a site
    who have received approval of use of an ordinance as an institutional control under
    this Section shall:
    1)
    Monitor activities of the unit of local government relative to variance
    requests or changes in the ordinance relative to the use of potable
    groundwater at properties identified in subsection (b)(4) (b)(3) of this
    Section; and
    2)
    Notify the Agency of any approved variance requests or ordinance changes
    within 30 days after the date such action has been approved.
    31
    e)
    The information required in subsections (b)(1) through (b)(6) (b)(5) of this Section
    and the Agency letter approving the groundwater remediation objective shall be
    submitted to the unit of local government. Proof that the information has been filed
    with the unit of local government shall be provided to the Agency.
    f)
    Any ordinance or MOU used as an institutional control pursuant to this Section
    shall be recorded in the Office of the Recorder or Registrar of Titles of the county
    in which the site is located together with the instrument memorializing the Agency's
    no further remediation determination pursuant to the specific program within 45
    days after receipt of the Agency's no further remediation determination.
    g)
    An institutional control approved under this Section shall not become effective until
    officially recorded in accordance with subsection (f) of this Section. The person
    receiving the approval shall obtain and submit to the Agency within 30 days after
    recording a copy of the institutional control demonstrating that it has been recorded.
    h)
    The following shall be grounds for voidance of the ordinance as an institutional
    control and the instrument memorializing the Agency's no further remediation
    determination:
    1)
    Modification of the ordinance by the unit of local government to allow
    potable use of groundwater;
    2)
    Approval of a site-specific request, such as a variance, to allow potable
    use of groundwater at a site identified in subsection (b)(4) (b)(3) of this
    Section; or
    3)
    Violation of the terms of an institutional control recorded under Section
    742.1005 or Section 742.1010.
    i)
    The Agency and a unit of local government may enter into a MOU under this
    Section if the unit of local government has adopted an ordinance satisfying
    subsection (a) of this Section and if the requirements of this subsection are met.
    The MOU shall include the following:
    1)
    Identification of the authority of the unit of local government to enter the
    MOU;
    2)
    Identification of the legal boundaries, or equivalent, under which the
    ordinance is applicable;
    3)
    A certified copy of the ordinance;
    4)
    A commitment by the unit of local government to notify the Agency of any
    variance requests or proposed ordinance changes at least 30 days prior to
    the date the local government is scheduled to take action on the request or
    proposed change;
    32
    5)
    A commitment by the unit of local government to maintain a registry of all
    sites within the unit of local government that have received no further
    remediation determinations pursuant to specific programs and
    6)
    If the ordinance does not expressly prohibit the installation of potable water
    supply wells (and the use of such wells) by units of local government, a
    commitment by the unit of local government:
    A)
    To review the registry of sites established under subsection (i)(5) of
    this Section prior to siting potable water supply wells within the
    area covered by the ordinance;
    B)
    To determine whether the potential source of potable water may be
    or has been affected by contamination left in place at those sites; and
    C)
    To take whatever steps are necessary to ensure that the potential
    source of potable water is protected from the contamination or
    treated before it is used as a potable water supply.
    (Source: Amended in R00-19(B) at 24 Ill. Reg. _______, effective ____________________)
    Section 742.1020
    Highway Authority Agreements
    a)
    An agreement with a highway authority may be used as an institutional control
    where the requirements of this Section are met and the Agency has determined that
    no further remediation is required as to the property(ies) to which the agreement is
    to apply.
    b)
    As part of the agreement the highway authority shall agree to:
    1)
    Prohibit the use of groundwater under the highway right of way that is
    contaminated above residential Tier 1 remediation objectives from the
    release as a potable supply of water.; and
    2)
    Limit access to soil contamination under the highway right of way that is
    contaminated above residential Tier 1 remediation objectives from the
    release. Access to soil contamination may be allowed if, during and after
    any access, public health and the environment are protected.
    c)
    A request for approval of an agreement as an institutional control The agreement
    shall provide the following:
    1)
    A copy of the agreement executed Fully executed signature blocks by the
    highway authority and the owner of the property (or, in the case of a
    petroleum leaking underground storage tank, the owner or operator of the
    tank) from which the release occurred;
    33
    2)
    A scaled map delineating the areal area and extent of soil and groundwater
    contamination above the applicable Tier 1 remediation objectives or a
    statement that either soil or groundwater is not contaminated above the
    applicable Tier 1 residential remediation objectives;
    3)
    Information showing the concentration of contaminants of concern within the
    zone in which the applicable Tier 1 remediation objectives are exceeded;
    4)
    A stipulation of the information required by subsections (b) (c)(2) and (3)
    of this Section in the agreement if it is not practical to obtain the information
    by sampling the highway right-of-way; and
    5)
     
    Information identifying the current fee owner of the highway
    right-of-way and highway authority having jurisdiction.
    d)
    Highway Authority Agreements must be referenced in the instrument that is to be
    recorded on the chain of title for the remediation property.
    ed)
    Violation of the terms of an Agreement approved by the Agency as an institutional
    control under this Section shall be grounds for voidance of the Agreement as an
    institutional control and the instrument memorializing the Agency's no further
    remediation determination.
    f)
    Failure to provide all of the information required in subsections (b) and (c) of this
    Section will be grounds for denial of the highway authority agreement as an
    institutional control.
    (Source: Amended in R00-19(B) at 24 Ill. Reg. _______, effective ____________________)
    SUBPART K: ENGINEERED BARRIERS
    Section 742.1105
    Engineered Barrier Requirements
    a)
    Natural attenuation, access controls, and point of use treatment shall not be
    considered engineered barriers. Engineered barriers may not be used to prevent
    direct human exposure to groundwater without the use of institutional controls.
    b)
    For purposes of determining remediation objectives under Tier 1, engineered
    barriers are not recognized.
    c)
    The following engineered barriers are recognized for purposes of calculating
    remediation objectives that exceed residential remediation objectives:
    1)
    For the soil component of the groundwater ingestion exposure route, the
    following engineered barriers are recognized if they prevent completion of
    the exposure pathway:
    34
    A)
    Caps, covering the contaminated media, or walls constructed of
    compacted clay, asphalt, concrete or other material approved by the
    Agency; and
    B)
    Permanent structures such as buildings and highways.
    2)
    For the soil ingestion exposure route, the following engineered barriers are
    recognized if they prevent completion of the exposure pathway:
    A)
    Caps, covering the contaminated media, or walls, constructed of
    compacted clay, asphalt, concrete, or other material approved by the
    Agency;
    B)
    Permanent structures such as buildings and highways; and
    C)
    Clean soil, covering the contaminated media, that is a minimum of
    three feet in depth.
    C)
    Soil, sand, gravel, or other geologic materials that:
    i)
    Cover the contaminated media;
    ii)
    Meet the soil remediation objectives under Subpart E for
    residential property for contaminants of concern; and
    iii)
    Are a minimum of three feet in depth.
    3)
    For the inhalation exposure route, the following engineered barriers are
    recognized if they prevent completion of the exposure pathway:
    A)
    Caps, covering the contaminated media, or walls constructed of
    compacted clay, asphalt, concrete, or other material approved by the
    Agency;
    B)
    Permanent structures such as buildings and highways; and
    C)
    Clean soil covering the contaminated media, that is a minimum of
    ten feet in depth and not within ten feet of any manmade pathway.
    C)
    Soil, sand, gravel, or other geologic materials that:
    i)
    Cover the contaminated media;
    ii)
    Meet the soil remediation objectives under Subpart E for
    residential property for contaminants of concern; and
    iii)
    Are a minimum of ten feet in depth and not within ten feet of
    any manmade pathway.
    35
    4)
    For the ingestion of groundwater exposure route, the following engineered
    barriers are recognized if they prevent completion of the exposure pathway:
    A)
    Slurry walls; and
    B)
    Hydraulic control of groundwater.
    d)
    Unless otherwise prohibited under Section 742.1100, any other type of engineered
    barrier may be proposed if it will be as effective as the options listed in subsection
    (c) of this Section.
    (Source: Amended in R00-19(B) at 24 Ill. Reg. _______, effective ____________________)

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