ILLINOIS POLLUTION CONTROL BOARD
December 4, 1997
IN THE MATTER OF:
TIERED APPROACH TO CORRECTIVE
ACTION OBJECTIVES (TACO):
AMENDMENTS TO 35 ILL.
ADM. CODE 742.105, 742.200, 742.505,
742.805, and 742.915
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R97-12(B)
(Rulemaking - Land)
Adopted Rule. Final Order.
OPINION AND ORDER OF THE BOARD (by M. McFawn and J. Yi):
The Board adopts today as final amendments to 35 Ill. Adm. Code 742: Tiered
Approach to Corrective Action Objectives, also known as TACO. The TACO program
establishes a three tiered approach for establishing corrective action objectives,
i.e.,
remediation objectives based on risks to human health and the environment, allowing for
consideration of the proposed land use at a subject site. The amendments adopted today (also
know as the mixture rule) address the effect of similar-acting chemicals on the same target
organ when determining remediation objectives under TACO. Specifically, the amendments
consider the effects of similar-acting chemicals,
i.e.,
noncarcinogens and carcinogens, under
Tiers 1, 2, and 3 of the TACO process. The statutory premise for the mixture rule is found at
Section 58.5(c) of the Illinois Environmental Protection Act (Act) (415 ILCS 5/58.5(c) (1996))
and 35 Ill. Adm. Code 620 of the Board’s regulations. The amendments were originally
proposed by the Illinois Environmental Protection Agency (Agency) during the course of
Docket A of this rulemaking.
1
PROCEDURAL MATTERS
Public hearings were held in Docket B on May 21, 1997, and May 29, 1997, to
consider the proposal of the Agency.
2
On July 10, 1997, the Board proceeded to first notice,
pursuant to the Illinois Administrative Procedure Act (APA) (5 ILCS 100/1-1 (1996)).
Subsequently, on July 25, 1997, the amendments to Part 742 were published in the
Illinois
Register
(21 Ill. Reg. 9687 (July 25, 1997)), upon which a 45-day comment period began.
One such comment was received by the Site Remediation Advisory Committee (SRAC). On
October 2, 1997, the Board adopted the amendments for second notice review by the Joint
Committee on Administrative Rules (JCAR). On November 12, 1997, JCAR issued a
certificate of no objection. No substantive changes were requested by JCAR. A few minor
1
See Tiered Approach to Corrective Action Objectives (TACO): 35 Ill. Adm. Code 742 (June
5, 1997), R97-12(A) (effective July 1, 1997).
2
The May 21, 1997, hearing will be referred to as Tr.1 at __; the May 29, 1997, hearing will
be referred to as Tr.2 at __.
2
editorial changes were suggested by JCAR and those changes have been incorporated into the
final order.
On April 17, 1997, the Board adopted for second notice the majority of TACO rules
under Docket A which were adopted as final on June 5, 1997.
3
At second notice and at final
notice during Docket A, the Board adopted a limited mixture rule at the recommendation of
the Agency. However, the record did not support the entire mixture rule proposed by the
Agency. On that same day, the Board opened this Docket B to fully consider the type and to
what extent a mixture rule is necessary under TACO to protect human health. The purpose of
bifurcating the rulemaking was twofold. First, under Docket A, the Board could proceed to
adopt the TACO methodology as final at new Part 742 in tandem with the rulemaking, In the
Matter of: the Site Remediation Program and Groundwater Quality Standards (June 5, 1997),
R97-11, which had a statutory deadline of June 16, 1997. Second, Docket B allowed the
Board to consider the full measure of a mixture rule necessary to protect human health.
On December 3, 1997, the SRAC and the Agency filed a “Joint Motion to Correct”
(joint motion) wherein they request that the Board change the risk concentrations listed in
Appendix A.Table H: “Chemicals Whose Tier I Class Groundwater Remediation Objective
Exceed the 1 in 1,000,000 Cancer Risk Concentration” (Table H). At this point in the R97-
12 rulemaking process, the APA does not provide for the expeditious correction of Table H.
See 5 ILCS 5-40(c), (d) (1994). So the merits and evidence necessary to support the joint
motion can be considered, the Board will today open a Docket C in this rulemaking. See In
the Matter of: Tiered Approach to Corrective Action Objectives: Amendments to Part 742
(December 4, 1997), R97-12(C). The Board intends to expedite rulemaking under this new
docket to the extent possible under the APA.
ESTABLISHING REMEDIATION OBJECTIVES USING THE MIXTURE RULE
The TACO methodology codified at Part 742 is not independent. It must be used in
conjunction with remediation programs, most specifically found at Part 740: Site Remediation
Program; Part 732: Underground Storage Tank rules; and the closure requirements under the
Resource Conservation and Recovery program at Parts 724 and 725. Regardless of the
remediation program with which TACO is being used, the TACO rules provide a three tiered
approach for establishing remediation objectives based upon risks to human health and the
environment, allowing for consideration of the proposed land use at the subject site. The
mixture rule adopted today requires further evaluation of the soil and/or groundwater
remediation objectives established for multiple, similar-acting chemicals under any of the three
tiers.
A Tier 1 analysis requires the remediation applicant to compare contamination levels of
contaminants of concern at the remediation site to predetermined corrective action objectives,
which are set forth in look-up tables in the rules in Appendix B. Generally, if any
3
The final rules were published in the
Illinois Register
at 21 Ill. Reg. 7942 (June 27, 1997).
3
contaminants of concern at a remediation site are found to exceed the predetermined levels, the
remediation applicant is required to remediate the contamination until the corrective action
objectives are achieved, or alternatively, to develop site-specific remediation objectives using a
Tier 2 or Tier 3 analysis. However, if the contaminants of concern in Class I groundwater at a
site include multiple, similar-acting chemicals, the instant regulations require further
evaluation to assess the mixture effect of such chemicals using the procedures specified under
Tier 2 or Tier 3. Such an evaluation must be performed if the contaminants of concern in
Class I groundwater include: more than one similar-acting noncarcinogen; or at least one
similar-acting carcinogen whose Tier 1 Class I groundwater remediation objective exceeds the
1 in 1,000,000 cancer risk concentration and one other similar-acting carcinogen.
A Tier 2 analysis uses the equations set forth in the rules to develop alternate
remediation objectives for contaminants of concern, using site-specific information. The
equations used to develop site-specific remediation objectives are from the United States
Environmental Protection Agency’s Soil Screening Level (SSL) and the American Society for
Testing and Material’s Risk Based Corrective Action (RBCA) approaches, and they are listed
in the rules in Appendix C. If any contaminants of concern are found to exceed the
remediation objectives developed using the Tier 2 equations, the remediation applicant is
required to remediate the contamination until the objectives are achieved, remediate to Tier 1
objectives, or develop alternate objectives using a Tier 3 analysis. The mixture rule described
above for evaluating the cumulative effect of multiple similar-acting noncarcinogens and
carcinogens in groundwater is also applicable at sites evaluated under Tier 2. Additionally,
under Tier 2 there is a mixture rule applicable when multiple similar-acting noncarcinogens are
detected in the soil at these sites.
A Tier 3 analysis allows a remediation applicant to develop remediation objectives
using alternative parameters not found in Tier 1 or Tier 2. It allows a remediation applicant to
use modified parameters, provided the remediation applicant provides justification for the
modification, and the technical and mathematical basis for the modification. Additionally, a
Tier 3 analysis allows a remediation applicant to use alternative models if certain information
is provided, including a licensed copy of the model, the mathematical and technical basis for
the model, and a demonstration that the model was correctly applied. If any contaminants of
concern are found to exceed the remediation objectives developed using the Tier 3 analysis, the
remediation applicant is required to remediate the contamination until the objectives are
achieved. Finally, the mixture rule is applicable when multiple, similar-acting chemicals are
detected in groundwater or in soil under Tier 3.
SUMMARY OF THE MIXTURE RULE
As explained in our Docket A second notice opinion of April 17, 1997, the record
before the Board at the time was insufficient to adopt the entire mixture rule ultimately
requested by the Agency. See In the Matter: Tiered Approach to Corrective Action
Objectives: 35 Ill. Adm. Code 742 (April 17, 1997), R97-12(A), slip op. at 3. However, we
found the justification provided did indicate that absent such a rule, remediation objectives
4
determined using TACO may not be protective of human health at sites with multiple, similar-
acting chemicals. Accordingly, a limited mixture rule was adopted under Docket A. That
interim rule is amended today.
Mixture Rule Under Docket A
The interim mixture rule adopted under Docket A at Part 742 provided that only the
cumulative effect of similar-acting noncarinogenic chemicals in groundwater be examined
under Tier 1 (Section 742.505(b)); it did not require that the cumulative effect of either
carcinogenic or noncarcinogenic contaminants be evaluated for soil. Under Tier 2, the
cumulative effects of noncarcinogenic contaminants in both soil and groundwater, respectively,
must be considered (at Sections 742.720 and 742.850(c)). As for similar-acting carcinogens in
groundwater or soil, their cumulative effect did not have to be evaluated under either Tier 1 or
Tier 2. Finally, under Tier 3, there was no mixture rule articulated for either type of
contaminant in either medium.
Mixture Rule Under Docket B
Having considered the evidence and the statutory mandates, the Board concludes that a
broader mixture rule is necessary to protect human health. Accordingly, Part 742 as adopted
under Docket A must be amended to accommodate such a rule. The mixture rules adopted
herein for each of the three tiers is slightly different than that adopted under Docket A and
described above. The mixture rule under Tier 1 still applies to similar-acting noncarcinogens
detected in Class I groundwater, but now also applies to certain similar-acting carcinogens in
groundwater whose Tier 1 Class I groundwater remediation objectives exceed the 1 in
1,000,000 cancer risk concentrations. Section 742.505(b)(3) and (4). There is still no mixture
rule applicable to either type of contaminant of concern in soil under Tier 1. The mixture rule
under Tier 2 likewise now applies to both similar-acting noncarcinogens and carcinogens in
groundwater (Section 742.805). As for soil, the mixture rule under Tier 2 is not amended; it
still only applies to noncarcinogens in soil. See Section 742.720. Finally, under Tier 3,
language is added which specifically provides a mixture rule. New Section 742.915(h)
requires that under Tier 3 both similar-acting carcinogens and noncarcinogens be evaluated for
both groundwater and soil.
Also adopted today are the definition of “similar-acting chemicals” and an Appendix
A.Table H. This new Table H lists those carcinogenic chemicals whose Tier 1 Class I
groundwater remediation objectives exceed the 1 in 1,000,000 cancer risk concentrations and
therefore must undergo either the Tier 2 or Tier 3 procedure for evaluating the mixture effect
of similar-acting chemicals. These two amendments serve to clarify how and when the rule is
applied under TACO.
HOW THE MIXTURE RULE WORKS
5
When considering the mixture rule to be applied under TACO, two questions must be
asked and answered initially: (1) is the rule being applied to determine groundwater or soil
remediation objectives; and (2) are the similar-acting contaminants of concern noncarcinogenic
or carcinogenic chemicals? Focusing on these questions assists the remediation applicant in
determining whether the mixture rule is applicable, as well as in better understanding the
evolution and purpose of the mixture rule adopted at Part 742.
These questions are, of course, preceded by the question as to whether multiple,
similar-acting chemicals are detected at the site. The mixture rule under any of the three tiers
is only applicable if multiple, similar-acting chemicals are present.
“Similar-acting chemicals” is defined as:
“chemical substances that have toxic or harmful effect on the same
specific organ or organ system. (See Appendix A.Tables E and F, for a
list of similar-acting chemicals with noncarcinogenic and carcinogenic
effects.)
This definition of similar-acting chemicals parallels the description of similar-acting chemicals
found at 35 Ill. Adm. Code 620.615. Although that rule concerns similar-acting chemicals in
groundwater, the mixture rule originates from that regulation. The purpose of the mixture
rule is to assess the cumulative effect of similar-acting chemicals as necessary to protect human
health if they are detected in groundwater or soil.
Are The Similar-Acting Chemicals Noncarcinogens?
The list of similar-acting noncarcinogens is found at Appendix A.Table E. If more
than one noncarcinogen on that list is detected in a single medium, groundwater or soil, the
mixture rule may be applicable. It is not necessary that either noncarcinogen be detected at a
level which exceed the remediation objectives established under Tier 1, Tier 2, or Tier 3.
As for the medium, under Tier 1 the mixture rule is only applicable if the
noncarcinogens are detected in the groundwater. Under Tier 2, the mixture rule is applicable
if the similar-acting noncarcinogens are detected in either medium--groundwater or soil.
Likewise the mixture rule is applicable under Tier 3 to similar-acting noncarcinogens found in
either medium. Section 742.915(h).
Are The Similar-Acting Chemicals Carcinogens?
6
The complete list of similar-acting carcinogens is found at Appendix A.Table F. There
is a second, short list of similar-acting carcinogens found at Appendix A.Table H.
4
This new
list, adopted today, lists 25 similar-acting carcinogens whose Tier 1 Class I groundwater
remediation objective exceed the 1 in 1,000,000 cancer risk concentrations. If at least one
carcinogen on that list is detected in the Class I groundwater at the site along with another
similar-acting carcinogen, the mixture rule will apply. It is not necessary that either similar-
acting carcinogen be detected at a level which exceed the remediation objectives established
under Tier 1, Tier 2, or Tier 3.
As for carcinogens in soil, there is no mixture rule for similar-acting carcinogens
detected in soil under either Tier 1 or Tier 2. Again, however, Tier 3 does not distinguish the
applicability of the mixture rule based upon the medium. Pursuant to Section 742.915(h), if
multiple carcinogens listed on Table F of Appendix A are detected in groundwater or soil and
the remediation applicant is conducting a Tier 3 analysis, the cumulative effect of these
contaminants must be addressed.
What if the Similar-Acting Chemicals Are Detected In Groundwater?
If the presence of noncarcinogens or carcinogens detected in groundwater trigger the
mixture rule, the remediation applicant must take steps to satisfy Section 620.615 of the
Board’s groundwater regulations. Sections 742.505(b)(3) and 742.805(c) and (d) of Part 742
cross-reference Section 620.615 of the Board’s groundwater quality standards. The mixture
rule originates from that regulation. Under each of these TACO regulations, Section 620.615
is deemed satisfied if the conditions triggering the mixture rule are not present at the site. If
they are present and the mixture rule is applicable, the remediation applicant must take steps to
ensure that Section 620.615 is satisfied.
The steps necessary are set out in the rules. First, under all three tiers if more than one
similar-acting noncarcinogenic chemical is detected at the site, the mixture rule set out at
Section 742.805(c) or that developed under Tier 3 must be applied. Second, if a carcinogenic
chemical listed on Appendix A.Table H is detected at the site along with a similar-acting
carcinogen listed on Appendix A.Table F, the mixture rule at Section 742.805(d) or that
developed under Tier 3 must be applied.
SUMMARY OF FINDINGS
Tier 1
Based on the evidence presented to the Board by the Agency in Dockets A and B, the
Board finds (1) that a mixture rule is not necessary for either noncarcinogenic or carcinogenic
4
As explained above under “Procedural Matters,” this new Table H in Appendix A is the
subject of further rulemaking under Docket C and amendments thereto will be proposed at first
notice under the APA.
7
chemicals when developing soil remediation objectives under Tier 1, and (2) that a mixture
rule is necessary for both similar-acting noncarcinogenic and carcinogenic chemicals when
developing groundwater remediation objectives under Tier 1.
Our first finding is based on testimony from Dr. Hornshaw at hearing that the inherent
protection built into the process of developing the Tier 1 soil remediation objectives, for
similar-acting noncarcinogens and carcinogenic, makes consideration of the additivity of
effects of similar-acting chemicals unnecessary in Tier 1. Tr.1 at 14, 19. Accordingly, Tier 1
contains no requirements that similar-acting noncarcinogens or carcinogens be considered in
developing soil remediation objectives.
Given our second finding, Tier 1 contains a mixture rule for similar-acting
noncarcinogens and carcinogens in groundwater although the Agency and participants
requested that the Tier 1 mixture rule apply only to carcinogens in groundwater. Under
Docket A, we adopted a mixture rule applicable to noncarcinogens in groundwater because the
evidence demonstrated that such such a rule is necessary to protect public health. Nothing in
the record developed in this Docket supports changing that finding.
In Docket A, the Agency advocated that the Board adopt a mixture rule for both
similar-acting carcinogenic and noncarcinogenic chemicals in groundwater. In Docket B,
however, the Agency advocated such a rule for carcinogens only for policy reasons. At
hearing, Dr. Hornshaw testified that the Agency and the SRAC agreed that consideration of
mixtures of similar-acting chemicals is not necessary under Tier 1 except for those carcinogens
whose groundwater remediation objectives are not based on a 1 in 1,000,000 cancer risk. Tr.1
at 23. The Agency and the participants believed that the preferred policy is the simplicity of
look-up tables under Tier 1 for noncarcinogens under Tier 1 at the expense of a mixture rule.
The Board sympathizes with the desire of the Agency and the participants for the
simplicity of look-up tables under Tier 1, but the evidence does not support a simple look-up
table when the cumulative effect of similar-acting noncarcinogenic chemicals in groundwater
exceeds the hazard quotient of one. A hazard quotient, also referred to as a hazard index, is
the ratio of the chemical level present at a site and the acceptable level of each similar-acting
chemical. If the hazard quotient exceeds one, pursuant to Section 620.615 of the groudwater
rules, and therefore Section 742.805 (c) which cross references it, the groundwater
remediation objectives must be corrected to levels equal to or less than one. As we found in
Docket A, this analysis is necessary to protect human health. Furthermore, we find that the
burden on a remediation applicant to determine the cumulative effect of similar-acting
noncarcinogenic chemicals and to correct the remediation objectives as necessary is not unduly
burdensome. See In the Matter of: Tiered Approach to Corrective Action Objectives:
Amendments to Part 742 (October 2, 1997), R97-12(B), slip op. at 6-7.
Further, the Board finds that the mandate of Section 58.5(c) prevails over the Agency’s
policy argument, and a mixture rule is necessary to protect human health. The mixture rule
assures that the cumulative effect of similar-acting chemicals in groundwater is evaluated, and
8
the applicable remediation objectives are corrected to a level which does not pose a risk to
human health. This is equally true for both carcinogens and noncarcinogens. We note that that
the Agency proposed more than a look-up table for carcinogens,
i.e.
, that a mixture rule must
be applied to determine the appropriate groundwater remediation objective. Accordingly, the
current rule that similar-acting noncarcinogenic chemicals be evaluated under Tier 1 for
groundwater is retained at Section 742.505(b)(3)(A), but amended at Section 742.505(B)(3)(B)
to include the same requirement for carcinogenic chemicals when a carcinogenic chemical with
a remediation objective set at a risk level higher than 1 in 1,000,000 is detected at the site
along with another similar-acting carcinogens. A list of those carcinogens is adopted as
proposed by the Agency. Tr.1 at 23-27, 36. Today we adopt as final this two-part rule as the
mixture rule for a Tier 1 analysis.
Tier 2
The Board’s finding under Docket A that a mixture rule for similar-acting
noncarcinogenic chemicals is necessary for soil and groundwater remediation objectives
remains unchanged. Accordingly, the mixture rule adopted under Docket A which applies to
similar-acting noncarcinogenic chemicals under Tier 2 is retained. The groundwater
component of this rule is amended, however, to require that the cumulative effect of
carcinogenic chemicals with Class I groundwater remediation objectives in excess of 1 in
1,000,000 cancer risk concentrations (Appendix A.Table H carcinogens) be evaluated when
developing groundwater remediation objectives.
As for mixtures of similar-acting noncarcinogenic chemicals in groundwater, we agree
with the Agency and the SRAC that consideration of similar-acting noncarcinogenic chemicals
under Tier 2 is required. Tr.1 at 20.
With regard to mixtures of carcinogenic chemicals in groundwater under Tier 2, the
Board finds that there are carcinogenic chemicals whose groundwater objectives exceed the 1
in 1,000,000 cancer risk level, and which, if present in a mixture with other similar-acting
carcinogenic chemicals, could potentially result in a cumulative cancer risk exceeding 1 in
10,000. Tr.1 at 24. Therefore, the Board concludes that similar-acting carcinogenic
chemicals whose Tier 1 groundwater objectives exceed the 1 in 1,000,000 risk level must be
evaluated for mixture effects under Tier 2. Tr.1 at 24. To facilitate such an evaluation, those
similar-acting carcinogenic chemicals whose Tier 1 groundwater remediation objectives exceed
the 1 in 1,000,000 risk level will be specifically identified in a look-up table. Tr.1 at 24; See
Exh. 1, Appendix A.Table H.
The Tier 2 mixture rule for soil remediation objectives remains unchanged, applicable
only to similar-acting noncarcinogenic chemicals. Unlike Tier 1, Tier 2 requires that similar-
acting noncarcinogenic chemicals be considered in developing soil remediation objectives. It
does not require that carcinogenic chemicals listed on Table H be considered. The Board finds
that it is only necessary to address mixture effects of similar-acting noncarcinogenic chemicals
because, concerning carcinogenic chemicals, the language of Section 58.5(d) of the Act
9
specifically provides for the establishment of remediation objectives at an excess lifetime
cancer risk of between 1 in 10,000 and 1 in 1,000,000. Tr.1 at 15.
Tier 3
Tier 3 contains a requirement that similar-acting carcinogens and noncarcinogens be
considered when developing both soil and groundwater remediation objectives. Under Docket
A, language for a mixture rule was not adopted under Tier 3. We have decided to amend
Section 742.915(h) to include such language to ensure that the cumulative effects of both
carcinogenic and noncarcinogenic chemicals are evaluated under the Tier 3 site-specific
approach.
As noted in our final opinion in Docket A of June 5, 1997, remediation objectives
greater than the Part 620 groundwater quality standards may only be developed under Tier 3.
See Section 742.105(f). There is no evidence on the record to support this provision. Instead,
it is provided because Section 58.5 of the Act allows the remediation applicant to propose, and
the Agency to approve pursuant to Tier 3 of TACO, remediation objectives greater than the
State’s groundwater quality standards. Although we anticipated possibly considering under
this docket whether such remediation objectives might also be allowed under Tier 1 or Tier 2,
no evidence supporting the same was offered. We note, however, that groundwater
remediation objectives greater than the State’s groundwater quality standards may be
established under Tier 2 so long as the State’s groundwater quality standard is met at the point
of human exposure.
CONCLUSIONS
The Board proposes for adoption the same mixture rule as that proposed for first and
second notice. The mixture rule for similar-acting chemicals in soil is graduated. At Tier 1, it
is not applicable. At Tier 2, it is applicable to noncarcinogens only. And, at Tier 3, it is
applicable to carcinogens and noncarcinogens. The mixture rule for similar-acting chemicals
in Class I groundwater uniformly spans all three tiers of TACO. It is applicable to both
similar-acting carcinogens and noncarcinogens under all three tiers. The mixture rule is
basically that proposed by the Agency in this docket with one exception. That exception is
that the mixture rule under Tier 1 applies to similar-acting noncarcinogenic chemicals as well
as similar-acting carcinogens detected in groundwater at sites being analyzed under TACO.
Further, the Board concludes, as we did at first and second notice, that a mixture rule
for similar-acting noncarcinogenic chemicals in groundwater is required under Tier 1, as well
as under Tiers 2 and 3, because the remediation objective for similar-acting noncarcinogenic
chemicals in groundwater is premised upon a hazard quotient of one. Finally, having
proposed the mixture rule to be all-inclusive, the Board adopts the cross-reference to Section
620.615 of the Board’s groundwater rules. Thus, the remediation applicant and the public are
assured that an evaluation of similar-acting chemicals provided thereunder is also provided
under TACO.
10
ORDER
The Board directs the Clerk to cause the filing of the following adopted rule for final
notice publication in the
Illinois Register
with the Secretary of State:
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
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
11
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
SUBPART F: TIER 2 GENERAL EVALUATION
Section
742.600
Tier 2 Evaluation Overview
742.605
Land Use
742.610
Chemical and Site Properties
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
12
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
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
0
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 with Noncarcinogenic Toxic
Effects on Specific Target Organs/Organ Systems or Similar Modes of
Action
Table F
Similar-Acting Carcinogenic Chemicals with Carcinogenic Toxic Effects
on Specific Target Organs/Organ Systems or Similar Modes of Action
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
13
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
)
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].(see P.A. 88-496, effective
September 13, 1993 and P.A. 89-0431, effective December 15, 1995).
MAIN SOURCE: Adopted at 21 Ill. Reg. 7942, effective July 1, 1997, amended at 21 Ill.
Reg. __________________, effective __________________.
NOTE: Capitalization indicates statutory language.
SUBPART A: INTRODUCTION
Section 742.105
Applicability
a)
Any person, including a person required to perform an investigation pursuant to
the Illinois Environmental Protection Act (415 ILCS 5/1 et seq.) (Act), may
elect to proceed under this Part to the extent allowed by State or federal law and
14
regulations and the provisions of this Part. A person proceeding under this Part
may do so to the extent such actions are consistent with the requirements of the
program under which site remediation is being addressed.
b)
This Part is to be used in conjunction with the procedures and requirements
applicable to the following programs:
1)
Leaking Underground Storage Tanks (35 Ill. Adm. Code 731 and 732);
2)
Site Remediation Program (35 Ill. Adm. Code 740); and
3)
RCRA Part B Permits and Closure Plans (35 Ill. Adm. Code 724 and
725).
c)
The procedures in this Part may not be used if their use would delay response
action to address imminent and substantial threats to human health and the
environment. This Part may only be used after actions to address such threats
have been completed.
d)
This Part may be used to develop remediation objectives to protect surface
waters, sediments or ecological concerns, when consistent with the regulations
of other programs, and as approved by the Agency.
e)
A no further remediation determination issued by the Agency prior to July 1,
1997 pursuant to Section 4(y) of the Act or one of the programs listed in
subsection (b) of this Section that approves completion of remedial action
relative to a release shall remain in effect in accordance with the terms of that
determination.
f)
Site specific groundwater remediation objectives determined under this Part for
contaminants of concern may exceed the groundwater quality standards
established pursuant to the rules promulgated under the Illinois Groundwater
Protection Act (415 ILCS 55) as long as done in accordance with Sections
742.805(a) and 742.900(c)(9). (See 415 ILCS 5/58.5(d)(4)
g)
Where contaminants of concern include polychlorinated byphenyls (PCBs), a
person may need to evaluate the applicability of regulations adopted under the
Toxic Substances Control Act (15 U.S.C. 2601).
SOURCE: Amended at 21 Ill. Reg. ______________ , effective __________________.
SUBPART B: GENERAL
Section 742.200
Definitions
15
Except as stated in this Section, or unless a different meaning of a word or term is clear
from the context, the definition of words or terms in this Part shall be the same as that applied
to the same words or terms in the Act.
“Act” means the Illinois Environmental Protection Act [415 ILCS 5/1 et seq.].
“ADL” means Acceptable Detection Limit, which is the detectable
concentration of a substance which is equal to the lowest appropriate Practical
Quantitation Limit (PQL) as defined in this Section.
“Agency” means the Illinois Environmental Protection Agency.
“Agricultural Property” means any real property for which its present or post-
remediation use is for growing agricultural crops for food or feed either as
harvested crops, cover crops or as pasture. This definition includes, but is not
limited to, properties used for confinement or grazing of livestock or poultry
and for silviculture operations. Excluded from this definition are farm
residences, farm outbuildings and agrichemical facilities.
“Area Background” means CONCENTRATIONS OF REGULATED
SUBSTANCES THAT ARE CONSISTENTLY PRESENT IN THE
ENVIRONMENT IN THE VICINITY OF A SITE THAT ARE THE RESULT
OF NATURAL CONDITIONS OR HUMAN ACTIVITIES, AND NOT THE
RESULT SOLELY OF RELEASES AT THE SITE. (Section 58.2 of the Act)
“ASTM” means the American Society for Testing and Materials.
“Board” means the Illinois Pollution Control Board.
“Cancer Risk” means a unitless probability of an individual developing cancer
from a defined exposure rate and frequency.
“Cap” means a barrier designed to prevent the infiltration of precipitation or
other surface water, or impede the ingestion or inhalation of contaminants.
“Carcinogen” means A CONTAMINANT THAT IS CLASSIFIED AS A
CATEGORY A1 OR A2 CARCINOGEN BY THE AMERICAN
CONFERENCE OF GOVERNMENTAL INDUSTRIAL HYGIENISTS; A
CATEGORY 1 OR 2A/2B CARCINOGEN BY THE WORLD HEALTH
ORGANIZATION'S INTERNATIONAL AGENCY FOR RESEARCH ON
CANCER; A "HUMAN CARCINOGEN" OR "ANTICIPATED HUMAN
CARCINOGEN" BY THE UNITED STATES DEPARTMENT OF HEALTH
AND HUMAN SERVICE NATIONAL TOXICOLOGICAL PROGRAM; OR
16
A CATEGORY A OR B1/B2 CARCINOGEN BY THE UNITED STATES
ENVIRONMENTAL PROTECTION AGENCY IN the INTEGRATED RISK
INFORMATION SYSTEM OR A FINAL RULE ISSUED IN A FEDERAL
REGISTER NOTICE BY THE USEPA. (Section 58.2 of the Act)
“Class I Groundwater” means groundwater that meets the Class I: Potable
Resource Groundwater criteria set forth in 35 Ill.inois Adm.inistrative Code
620.
“Class II Groundwater” means groundwater that meets the Class II: General
Resource Groundwater criteria set forth in 35 Ill.inois Adm.inistrative Code
620.
“Conservation Property” means any real property for which present or post-
remediation use is primarily for wildlife habitat.
“Construction Worker” means a person engaged on a temporary basis to
perform work involving invasive construction activities including, but not
limited to, personnel performing demolition, earth-moving, building, and
routine and emergency utility installation or repair activities.
“Contaminant of Concern” or “Regulated Substance of Concern” means ANY
CONTAMINANT THAT IS EXPECTED TO BE PRESENT AT THE SITE
BASED UPON PAST AND CURRENT LAND USES AND ASSOCIATED
RELEASES THAT ARE KNOWN TO THE person conducting a remediation
BASED UPON REASONABLE INQUIRY. (Section 58.2 of the Act)
“Engineered Barrier” means a barrier designed or verified using engineering
practices that limits exposure to or controls migration of the contaminants of
concern.
“Exposure Route” means the transport mechanism by which a contaminant of
concern reaches a receptor.
“Free Product” means a contaminant that is present as a non-aqueous phase
liquid for chemicals whose melting point is less than 30
o
C (e.g., liquid not
dissolved in water).
“GROUNDWATER” MEANS UNDERGROUND WATER WHICH OCCURS
WITHIN THE SATURATED ZONE AND GEOLOGIC MATERIALS
WHERE THE FLUID PRESSURE IN THE PORE SPACE IS EQUAL TO OR
GREATER THAN ATMOSPHERIC PRESSURE. (Section 3.64 of the Act)
17
“Groundwater Quality Standards” means the standards for groundwater as set
forth in 35 Ill.inois Adm.inistrative Code 620.
“Hazard Quotient” means the ratio of a single substance exposure level during a
specified time period to a reference dose for that substance derived from a
similar exposure period.
“Highway” means ANY PUBLIC WAY FOR VEHICULAR TRAVEL WHICH
HAS BEEN LAID OUT IN PURSUANCE OF ANY LAW OF THIS STATE,
OR OF THE TERRITORY OF ILLINOIS, OR WHICH HAS BEEN
ESTABLISHED BY DEDICATION, OR USED BY THE PUBLIC AS A
HIGHWAY FOR 15 YEARS, OR WHICH HAS BEEN OR MAY BE LAID
OUT AND CONNECT A SUBDIVISION OR PLATTED LAND WITH A
PUBLIC HIGHWAY AND WHICH HAS BEEN DEDICATED FOR THE
USE OF THE OWNERS OF THE LAND INCLUDED IN THE
SUBDIVISION OR PLATTED LAND WHERE THERE HAS BEEN AN
ACCEPTANCE AND USE UNDER SUCH DEDICATION BY SUCH
OWNERS, AND WHICH HAS NOT BEEN VACATED IN PURSUANCE OF
LAW. THE TERM “HIGHWAY” INCLUDES RIGHTS OF WAY,
BRIDGES, DRAINAGE STRUCTURES, SIGNS, GUARD RAILS,
PROTECTIVE STRUCTURES AND ALL OTHER STRUCTURES AND
APPURTENANCES NECESSARY OR CONVENIENT FOR VEHICULAR
TRAFFIC. A HIGHWAY IN A RURAL AREA MAY BE CALLED A
“ROAD”, WHILE A HIGHWAY IN A MUNICIPAL AREA MAY BE
CALLED A “STREET”. (Illinois Highway Code [605 ILCS 5/2-202])
“Highway Authority” means THE DEPARTMENT of Transportation WITH
RESPECT TO A STATE HIGHWAY; THE COUNTY BOARD WITH
RESPECT TO A COUNTY HIGHWAY OR A COUNTY UNIT DISTRICT
ROAD IF A DISCRETIONARY FUNCTION IS INVOLVED AND THE
COUNTY SUPERINTENDENT OF HIGHWAYS IF A MINISTERIAL
FUNCTION IS INVOLVED; THE HIGHWAY COMMISSIONER WITH
RESPECT TO A TOWNSHIP OR DISTRICT ROAD NOT IN A COUNTY
UNIT ROAD DISTRICT; OR THE CORPORATE AUTHORITIES OF A
MUNICIPALITY WITH RESPECT TO A MUNICIPAL STREET. (Illinois
Highway Code [605 ILCS 5/2-213])
“Human Exposure Pathway” means a physical condition which may allow for a
risk to human health based on the presence of all of the following:
contaminants of concern; an exposure route; and a receptor activity at the point
of exposure that could result in contaminant of concern intake.
18
“Industrial/Commercial Property” means any real property that does not meet
the definition of residential property, conservation property or agricultural
property.
“Infiltration” means the amount of water entering into the ground as a result of
precipitation.
“Institutional Control” means a legal mechanism for imposing a restriction on
land use, as described in Subpart J.
“Man-Made Pathways” means CONSTRUCTED physical conditions THAT
MAY ALLOW FOR THE TRANSPORT OF REGULATED SUBSTANCES
INCLUDING, BUT NOT LIMITED TO, SEWERS, UTILITY LINES,
UTILITY VAULTS, BUILDING FOUNDATIONS, BASEMENTS, CRAWL
SPACES, DRAINAGE DITCHES, OR PREVIOUSLY EXCAVATED AND
FILLED AREAS. (Section 58.2 of the Act)
“Natural Pathways” means NATURAL physical conditions that may allow FOR
THE TRANSPORT OF REGULATED SUBSTANCES INCLUDING, BUT
NOT LIMITED TO, SOIL, GROUNDWATER, SAND SEAMS AND
LENSES, AND GRAVEL SEAMS AND LENSES. (Section 58.2 of the Act)
“Negative Easement” means a right of the owner of the dominant or benefitted
estate or property to restrict the property rights of the owner of the servient or
burdened estate or property.
“Person” means an INDIVIDUAL, TRUST, FIRM, JOINT STOCK
COMPANY, JOINT VENTURE, CONSORTIUM, COMMERCIAL ENTITY,
CORPORATION (INCLUDING A GOVERNMENT CORPORATION),
PARTNERSHIP, ASSOCIATION, STATE, MUNICIPALITY,
COMMISSION, POLITICAL SUBDIVISION OF A STATE, OR ANY
INTERSTATE BODY INCLUDING THE UNITED STATES GOVERNMENT
AND EACH DEPARTMENT, AGENCY, AND INSTRUMENTALITY OF
THE UNITED STATES. (Section 58.2 of the Act)
“Point of Human Exposure” means the point(s) at which human exposure to a
contaminant of concern may reasonably be expected to occur. The point of
human exposure is at the source, unless an institutional control limiting human
exposure for the applicable exposure route has been or will be in place, in
which case the point of human exposure will be the boundary of the institutional
control. Point of human exposure may be at a different location than the point
of compliance.
19
“PQL” means Practical Quantitation Limit or estimated quantitation limit,
which is the lowest concentration that can be reliably measured within specified
limits of precision and accuracy for a specific laboratory analytical method
during routine laboratory operating conditions in accordance with "Test
Methods for Evaluating Solid Wastes, Physical/Chemical Methods", EPA
Publication No. SW-846, incorporated by reference in Section 742.210. When
applied to filtered water samples, PQL includes the method detection limit or
estimated detection limit in accordance with the applicable method revision in:
"Methods for the Determination of Organic Compounds in Drinking Water",
Supplement II", EPA Publication No. EPA/600/4-88/039; "Methods for the
Determination of Organic Compounds in Drinking Water, Supplement III",
EPA Publication No. EPA/600/R-95/131, all of which are incorporated by
reference in Section 742.210.
“RBCA” means Risk Based Corrective Action as defined in ASTM E-1739-95,
as incorporated by reference in Section 742.210.
“RCRA” means the Resource Conservation and Recovery Act of 1976 (42
U.S.C. 6921).
“Reference Concentration (RfC)” means an estimate of a daily exposure, in
units of milligrams of chemical per cubic meter of air (mg/m
3
), to the human
population (including sensitive subgroups) that is likely to be without
appreciable risk of deleterious effects during a portion of a lifetime (up to
approximately seven years, subchronic) or for a lifetime (chronic).
“Reference Dose (RfD)” means an estimate of a daily exposure, in units of
milligrams of chemical per kilogram of body weight per day (mg/kg/d), to the
human population (including sensitive subgroups) that is likely to be without
appreciable risk of deleterious effects during a portion of a lifetime (up to
approximately seven years, subchronic) or for a lifetime (chronic).
“Regulated Substance” means ANY HAZARDOUS SUBSTANCE AS
DEFINED UNDER SECTION 101(14) OF THE COMPREHENSIVE
ENVIRONMENTAL RESPONSE, COMPENSATION, AND LIABILITY
ACT OF 1980 (P.L. 96-510) AND PETROLEUM PRODUCTS INCLUDING
CRUDE OIL OR ANY FRACTION THEREOF, NATURAL GAS, NATURAL
GAS LIQUIDS, LIQUEFIED NATURAL GAS, OR SYNTHETIC GAS
USABLE FOR FUEL (OR MIXTURES OF NATURAL GAS AND SUCH
SYNTHETIC GAS). (Section 58.2 of the Act)
“Residential Property” MEANS ANY REAL PROPERTY THAT IS USED
FOR HABITATION BY INDIVIDUALS, OR where children have the
opportunity for exposure to contaminants through soil ingestion or inhalation at
20
educational facilities, health care facilities, child care facilities or outdoor
recreational areas.
“Restrictive Covenant or Deed Restriction” means a provision placed in a deed
limiting the use of the property and prohibiting certain uses. (Black's Law
Dictionary, 5th Edition)
“Right of Way” means THE LAND, OR INTEREST THEREIN, ACQUIRED
FOR OR DEVOTED TO A HIGHWAY. (Illinois Highway Code [605 ILCS
5/2-217])
“Similar-Acting Chemicals” are chemical substances that have toxic or harmful
effect on the same specific organ or organ system (see Appendix A.Tables E
and F for a list of similar-acting chemicals with noncarcinogenic and
carcinogenic effects).
“Site” means ANY SINGLE LOCATION, PLACE, TRACT OF LAND OR
PARCEL OF PROPERTY, OR PORTION THEREOF, INCLUDING
CONTIGUOUS PROPERTY SEPARATED BY A PUBLIC RIGHT-OF-WAY.
(Section 58.2 of the Act)
“Slurry Wall” means a man-made barrier made of geologic material which is
constructed to prevent or impede the movement of contamination into a certain
area.
“Soil Saturation Limit (C
sat
)” means the contaminant concentration at which soil
pore air and pore water are saturated with the chemical and the adsorptive limits
of the soil particles have been reached.
“Solubility” means a chemical specific maximum amount of solute that can
dissolve in a specific amount of solvent (groundwater) at a specific temperature.
“SPLP” means Synthetic Precipitation Leaching Procedure (Method 1312) as
published in “Test Methods for Evaluating Solid Waste, Physical/Chemical
Methods”, USEPA Publication No. SW-846, as incorporated by reference in
Section 742.210.
“SSL” means Soil Screening Levels as defined in USEPA's Soil Screening
Guidance: User's Guide and Technical Background Document, as incorporated
by reference in Section 742.210.
“Stratigraphic Unit” means a site-specific geologic unit of native deposited
material and/or bedrock of varying thickness (e.g., sand, gravel, silt, clay,
bedrock, etc.). A change in stratigraphic unit is recognized by a clearly distinct
21
contrast in geologic material or a change in physical features within a zone of
gradation. For the purposes of this Part, a change in stratigraphic unit is
identified by one or a combination of differences in physical features such as
texture, cementation, fabric, composition, density, and/or permeability of the
native material and/or bedrock.
“TCLP” means Toxicity Characteristic Leaching Procedure (Method 1311) as
published in "Test Methods for Evaluating Solid Waste, Physical/Chemical
Methods,", USEPA Publication No. SW-846, as incorporated by reference in
Section 742.210.
“Total Petroleum Hydrocarbon (TPH)” means the additive total of all petroleum
hydrocarbons found in an analytical sample.
“Volatile Organic Compounds (VOCs)” means organic chemical analytes
identified as volatiles as published in "Test Methods for Evaluating Solid Waste,
Physical/Chemical Methods,", USEPA Publication No. SW-846 (incorporated
by reference in Section 742.210), method numbers 8010, 8011, 8015, 8020,
8021, 8030, 8031, 8240, 8260, 8315, and 8316. For analytes not listed in any
category in those methods, those analytes which have a boiling point less than
200
0
C and a vapor pressure greater than 0.1 Torr (mm Hg) at 20
0
C.
SOURCE: Amended at 21 Ill. Reg. ______________ , effective __________________.
SUBPART E: TIER I EVALUATION
Section 742.505
Tier 1 Soil and Groundwater Remediation Objectives
a)
Soil
1)
Inhalation Exposure Route
A)
The Tier 1 soil remediation objectives for this exposure route
based upon residential property use are listed in Appendix B,
Table A.
B)
The Tier 1 soil remediation objectives for this exposure route
based upon industrial/commercial property use are listed in
Appendix B, Table B. Soil remediation objective determinations
relying on this table require use of institutional controls in
accordance with Subpart J.
2)
Ingestion Exposure Route
22
A)
The Tier 1 soil remediation objectives for this exposure route
based upon residential property use are listed in Appendix B,
Table A.
B)
The Tier 1 soil remediation objectives for this exposure route
based upon industrial/commercial property use are listed in
Appendix B, Table B. Soil remediation objective determinations
relying on this table require use of institutional controls in
accordance with Subpart J.
3)
Soil Component of the Groundwater Ingestion Route
A)
The Tier 1 soil remediation objectives for this exposure route
based upon residential property use are listed in Appendix B,
Table A.
B)
The Tier 1 soil remediation objectives for this exposure route
based upon industrial/commercial property use are listed in
Appendix B, Table B.
C)
The pH-dependent Tier 1 soil remediation objectives for
identified ionizable organics or inorganics for the soil component
of the groundwater ingestion exposure route (based on the total
amount of contaminants present in the soil sample results and
groundwater classification) are provided in Appendix B, Tables C
and D.
D)
Values used to calculate the Tier 1 soil remediation objectives for
this exposure route are listed in Appendix B, Table F.
4)
Evaluation of the dermal contact with soil exposure route is not required
under Tier 1.
b)
Groundwater
1)
The Tier 1 groundwater remediation objectives for the groundwater
component of the groundwater ingestion route are listed in Appendix B,
Table E.
2)
The Tier 1 groundwater remediation objectives for this exposure route
are given for Class I and Class II groundwaters, respectively.
23
3)
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: The Class I groundwater
remediation objectives set forth in Appendix B, Table E shall be
corrected for cumulative effect of mixtures of similar-acting
noncarcinogenic chemicals in accordance with the methodoligies set
forth in either subsection (b)(3)(A) or (B), if more than one chemical
listed in Appendix A, Table E is detected at a site and if such chemicals
affect the same target organ (i.e., has the same critical effect as defined
by the RfD)
A)
No more than one similar-acting noncarcinogenic chemical as
listed in Appendix A, Table E is detected in the groundwater at
the site; and Calculate the weighted average using the following
equations:
W
ave =
x
CUO
x
CUO
x
CUO
x
CUO
x
x
x
a
x
a
1
2
3
1
2
3
+
+
+
+
K
where:
W
ave
= Weighted Average
x
1
through x
a
= Concentration of each individual contaminant at
the location of concern. Note that, depending on
the target organ/mode of action, the actual number
of contaminants will range from 2 to 14.
CUOx
a
= A Tier 1 remediation objective each x[a] from
Appendix B, Table E.
ii) 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.
ii) 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;
24
B)
No carcinogenic contaminant of concern as listed in Appendix A,
Table H is detected in any groundwater sample associated with
the site, using analytical procedures capable of achieving either
the 1 in 1,000,000 cancer risk concentration or the ADL,
whichever is greater. 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
4)
If the conditions of subsection (b)(3) of this Section are not met, the
Class I groundwater remediation objectives set forth in Appendix B,
Table E shall be corrected for the cumulative effect of mixtures of
similar-acting chemicals using the following methodologies:
A) For noncarcinogenic chemicals, the methodologies set forth at
Section 742.805(c) or Section 742.915(h) shall be used; and
B) For carcinogenic chemicals, the methodologies set forth at
Section 742.805(d) or Section 742.915(h) shall be used.
SOURCE: Amended at 21 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 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
25
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;
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: Groundwater remediation objectives for chemicals
which affect the same target organ, organ system or similar mode of action shall
be met the requirements of Section 743.505(b)(3). Contaminants of concern for
which a Tier 1 remediation objective has been developed shall be included in
any mixture of similar-acting substances under consideration in Tier 2.
26
1) Calculate the weighted average using the following equations:
W
ave =
x
CUO
x
CUO
x
CUO
x
CUO
x
x
x
a
x
a
1
2
3
1
2
3
+
+
+
+
K
where:
W
ave
= 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
.
i)
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.
ii)
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.
27
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 at 21 Ill. Reg. ______________ , effective __________________.
SUBPART I: TIER 3 EVALUATION
Section 742.915
Formal Risk Assessments
A comprehensive site-specific risk assessment shall demonstrate that contaminants of concern
at a site do not pose a significant risk to any human receptor. All site-specific risk assessments
shall be submitted to the Agency for review and approval. A submittal under this Section shall
address the following factors:
a)
Whether the risk assessment procedure used is nationally recognized and
accepted including, but not limited to, those procedures incorporated by
reference in Section 742.210;
b)
Whether the site-specific data reflect actual site conditions;
c)
The adequacy of the investigation of present and post-remediation exposure
routes and risks to receptors identified at the site;
d)
The appropriateness of the sampling and analysis;
e)
The adequacy and appropriateness of toxicity information;
f)
The extent of contamination;
g)
Whether the calculations were accurately performed; and
h)
Similar-acting chemicals shall be specifically addressed. At a minimum, the
chemicals subject to this requirement are identified in Appendix A, Tables E
and F; and
i)
Proposals seeking to modify the target risk consistent with Section 742.900(d)
shall address the following factors:
1)
the presence of sensitive populations;
28
2)
the number of receptors potentially impacted;
3)
the duration of risk at the differing target levels; and
4)
the characteristic of the chemicals of concern.
SOURCE: Amended at 21 Ill. Reg. ______________ , effective __________________.
Section 742.APPENDIX A:
General
Section 742.TABLE E:
Similar-Acting Noncarcinogenic Chemicals with Noncarcinogenic
Toxic Effects on Specific Target Organs/Organ Systems or
Similar Modes of Action
Kidney
Acetone
Cadmium (Ingestion only)
Chlorobenzene
Dalapon
1,1-Dichloroethane
Di-n-octyl phthalate
Endosulfan
Ethylbenzene
Fluoranthene
Nitrobenzene
Pyrene
Toluene
2,4,5-Trichlorophenol
Vinyl acetate
Liver
Acenaphthene
Acetone
Butylbenzyl phthalate
Chlorobenzene
1,1-Dichloroethylene
Endrin
Ethylbenzene
Fluoranthene
Nitrobenzene
Picloram
Styrene
2,4,5-TP (Silvex)
Toluene
2,4,5-Trichlorophenol
29
Central Nervous System
Butanol
Cyanide (amenable)
2,4-Dimethylphenol
Endrin
Manganese
2-Methylphenol
Mercury
Styrene
Xylenes
Circulatory System
Antimony
Barium
2,4-D
cis-1,2-Dichloroethylene
Nitrobenzene
trans-1,2-Dichloroethylene
2,4-Dimethylphenol
Fluoranthene
Fluorene
Styrene
Zinc
Gastrointestinal System
Endothall
Hexachlorocyclopentadiene
Methyl bromide
Reproductive System
Barium
Boron
Carbon disulfide
2-Chlorophenol
1,2 Dibromo-3-Chloropropane (Inhalation
only)
Dinoseb
Methoxychlor
Phenol
Cholinesterase Inhibition
Aldicarb
Carbofuran
Decreased Body Weight Gains
and Circulatory System Effects
Atrazine
Simazine
Adrenal Gland
Nitrobenzene
1,2,4-Trichlorobenzene
Respiratory System
1,2-Dichloropropane
Hexachlorocyclopentadiene
Methyl bromide
Vinyl acetate
Immune System
2,4-Dichlorophenol
p-Chloroaniline
SOURCE: Amended at 21 Ill. Reg. ______________ , effective __________________.
30
Section 742.APPENDIX A: General
Section 742.TABLE F:
Similar-Acting Carcinogenic Chemicals With
Carcinogenic Toxic Effects on Specific Target
Organs/Organ Systems or Similar Modes of Action
Kidney
Bromodichloromethane
Chloroform
1,2-Dibromo-3-chloropropane
2,4-Dinitrotoluene
2,6-Dinitrotoluene
Hexachlorobenzene
Liver
Aldrin
Bis(2-chloroethyl)ether
Bis(2-ethylhexyl)phthalate
Carbazole
Carbon tetrachloride
Chlordane
Chloroform
DDD
DDE
DDT
1,2-Dibromo-3-chloropropane
1,2-Dibromoethane
3,3'-Dichlorobenzidine
1,2-Dichloroethane
1,3-Dichloropropane (Ingestion only)
1,3-Dichloropropylene
Dieldrin
2,4-Dinitrotoluene
2,6-Dinitrotoluene
Heptachlor
Heptachlor epoxide
Hexachlorobenzene
alpha-HCH
gamma-HCH (Lindane)
Methylene chloride
N-Nitrosodiphenylamine
N-Nitrosodi-n-propylamine
Pentachlorophenol
Tetrachloroethylene
Trichloroethylene
31
2,4,6-Trichlorophenol
Toxaphene
Vinyl chloride
Circulatory System
Benzene
2,4,6-Trichlorophenol
Gastrointestinal System
Benzo(a)anthracene
Benzo(b)fluoranthene
Benzo(k)fluoranthene
Benzo(a)pyrene
Chrysene
Dibenzo(a,h)anthracene
Indeno(1,2,3-c,d)pyrene
Bromodichloromethane
Bromoform
1,2-Dibromo-3-chloropropane
1,2-Dibromoethane
1,3-Dichloropropylene
Lung
Arsenic
Beryllium (Inhalation only)
Cadmium (Inhalation only)
Chromium, hexavalent (Inhalation only)
1,3-Dichloropropylene
Methylene chloride
N-Nitrosodi-n-propylamine
Vinyl chloride
Nasal Cavity
1,2-Dibromo-3-chloropropane
(Inhalation only)
1,2-Dibromoethane (Inhalation only)
N-Nitrosodi-n-propylamine
Bladder
3,3'-Dichlorobenzidine
1,3-Dichloropropylene
N-Nitrosodiphenylamine
SOURCE: Amended at 21 Ill. Reg. ______________ , effective
__________________.
32
Section 742.APPENDIX A: General
TABLE H: Chemicals Whose Tier 1 Class I Groundwater Remediation Objective
Exceeds the 1 in 1,000,000 Cancer Risk Concentration.
Class I Groundwater 1 in 1,000,000 Cancer
Remediation Objective Risk Concentration ADL
Chemical (mg/l) (mg/l) (mg/l)
Aldrin 0.00004 0.000002 0.00004
Benzo(a)pyrene 0.0002 0.000005 0.00023
Bis(2-chloroethyl)ether 0.01 0.00003 0.01
Bis(2-ethylhexyl)phthalate 0.006 0.003 0.0027
Carbon Tetrachloride 0.005 0.0003 0.00003
Chlordane 0.002 0.00003 0.00014
Dibenzo(a,h)anthracene 0.0003 0.000005 0.0003
1,2-Dibromo-3-chloropropane 0.0002 0.00003 0.0002
1,2-Dibromoethane 0.00005 0.0000004 0.00005
3,3'-Dichlorobenzidine 0.02 0.00008 0.02
1,2-Dichloroethane 0.005 0.0004 0.00003
Dieldrin 0.00002 0.000002 0.00002
Heptachlor 0.0004 0.000008 0.00003
Heptachlor epoxide 0.0002 0.000004 0.00032
Hexachlorobenzene 0.00006 0.00002 0.00006
alpha-HCH 0.00003 0.000006 0.00003
Tetrachloroethylene 0.005 0.0007 0.00001
Toxaphene 0.003 0.00003 0.00086
Vinyl chloride 0.002 0.000015 0.00006
Ionizable Organics
N-Nitrosodiphenylamine 0.01 0.007 0.01
N
-
Nitrosodi-n-propylamine 0.01 0.000005 0.01
Pentachlorophenol 0.001 0.0003 0.001
2,4,6-Trichlorophenol 0.0064 0.003 0.0064
Inorganics
Arsenic 0.05 0.00002 0.001
Beryllium 0.004 0.0000083 0.004
SOURCE: Added at 21 Ill. Reg. ______________ , effective __________________.
IT IS SO ORDERED.
33
Section 41 of the Environmental Protection Act, 415 ILCS 5/41 (1996),
provides for the appeal of final Board orders to the Illinois Appellate Court within 35
days of service of this order. Illinois Supreme Court Rule 335 establishes such filing
requirements. See 145 Ill. 2d R. 335; see also 35 Ill. Adm. Code 101.246, Motions
for Reconsideration.
I, Dorothy M. Gunn, Clerk of the Illinois Pollution Control Board, hereby
certify that the above opinion and order was adopted on the 4th day of December 1997,
by a vote of 6-0.
Dorothy M. Gunn, Clerk
Illinois Pollution Control Board
