| (a) General requirement. The person shall use the criteria
provided in subsections (b) - (j) of this section and the risk-based
exposure limit (RBEL) equations provided in the following figures,
as applicable, to establish RBELs appropriate for the type of chemical
of concern (COC), the complete and reasonably anticipated to be completed
exposure pathways, receptors, and land uses. The person shall establish
RBELs for carcinogenic COCs and noncarcinogenic COCs using the default
exposure factors provided in the following figure for residents and
commercial/industrial workers, unless the executive director approves
the use of alternate exposure factors in accordance with subsection
(j) of this section.
Attached Graphic
(b) Air inhalation RBEL. The air inhalation RBEL (Air RBELInh )
is the protective concentration of a COC in air at the point of exposure
(POE) for human inhalation.
(1) Under Tiers 2 and 3 as described in §350.75
of this title (relating to Tiered Human Health Protective Concentration
Level Evaluation), the person may use the lower of available eight-hour
time-weighted average occupational inhalation criteria (i.e., Occupational
Safety and Health Administration Permissible Exposure Limits, or American
Conference of Governmental Industrial Hygienists Threshold Limit Values),
as Air RBELInh for
inhalation pathways for commercial/industrial workers within the limits
of affected commercial/industrial properties which have a health and
safety plan in place. The health and safety plan shall be designed
to ensure compliance with the applicable occupational inhalation criteria
and require the monitoring of COC levels in the working air environment,
and specify actions that will be taken in the event of exceedance
of the occupational inhalation criteria. When occupational inhalation
criteria are used, the person shall provide documentation of the health
and safety plan, certify that the plan is followed, and demonstrate
that the off-site receptors are protected as required by §350.71(h)
of this title (relating to General Requirements). The use of occupational
inhalation criteria as RBELs shall require the person to comply with
the institutional control requirements in §350.111(b) and (b)(14)
of this title (relating to Use of Institutional Controls).
(2) The air RBELs may not exceed any other applicable
federal or state air quality standards.
(c) Soil dermal contact RBEL. The soil dermal contact
RBEL (Soil RBELDerm )
is the protective concentration of a COC at the POE in soil based
upon direct dermal contact to soil by humans. The soil dermal contact
RBEL shall also be based on COC-specific values for dermal absorption
fraction (ABS.d) and gastrointestinal absorption fraction (ABSGI ) provided in the following figure, unless
the executive director approves the use of alternate ABS.d and ABSGI values in accordance with subsection (j)(1)(A)
and (B) of this section. It is not necessary to calculate a soil dermal
contact RBEL for COCs with vapor pressure in mm of Hg greater than
or equal to 1.
Attached Graphic
(d) Soil ingestion RBEL. The soil ingestion RBEL (Soil RBELIng )
is protective concentration of a COC at the POE in soil based upon
human ingestion.
(e) Vegetable ingestion RBELs. The vegetable RBELs
(AbgVeg RBELIng and BgVeg RBELIng )
are the protective concentration of a COC in aboveground vegetables
and below-ground vegetables, respectively, for ingestion by residents.
The person shall establish RBELs for ingestion of aboveground vegetables
for all carcinogenic and noncarcinogenic COCs which are metals. In
addition, the person shall establish RBELs for ingestion of below-ground
vegetables for all carcinogenic and noncarcinogenic COCs with a dimensionless
Henry's Law Constant less than 0.03, as shown in the figure in §350.73(f)
of this title (relating to Determination and Use of Human Toxicity
Factors and Chemical Properties), when either of the following criteria
are met:
(1) the COC is a metal; or
(2) the COC has a logarithmic octanol-water partition
coefficient (Log Kow ) greater than four
as shown in the figure in §350.73(f) of this title ; or
(f) Groundwater ingestion RBEL.
(1) The groundwater ingestion RBEL (
GW RBELIng ) is the protective
concentration of a COC at the POE in groundwater based upon human
ingestion of groundwater. However, if available, the person shall
use the lower of the two values established under paragraphs (2) and
(3) of this subsection instead.
(2) The person shall use the primary maximum contaminant
level (MCL) as provided in 40 Code of Federal Regulations (CFR) Part
141, as amended, or the most currently available federal action level
for drinking water (e.g., lead and copper) as the RBEL when available
for the COC.
(3) The person shall use the secondary MCLs established
for individual COCs as provided in 40 CFR Part 143, as amended, as
RBELs, or other scientifically valid published criteria in cases where
COCs are present at concentrations which present objectionable characteristics
such as taste or odor (e.g., methyl tertiary butyl ether) under the
following circumstances:
(A) when the COCs are present in class 1 groundwater;
(B) when the COCs are present in class 2 groundwater
that is within 1/2 mile of a well used to supply drinking water and
is also within or is likely to migrate, based upon the chemical properties
of the COCs and the hydrogeology, to the groundwater production zone
of such drinking water supply well; or
(C) when the COCs are present in class 2 groundwater
and there are no alternative water supplies available.
(g) Class 3 groundwater RBEL. The class 3 groundwater
RBEL (GW RBELClass
3 ) is the acceptable concentration of a COC at the POE in
class 3 groundwater.
(h) Surface water RBEL. The surface water RBEL (SW RBEL) is the protective concentration of
a COC at the POE in surface water. To establish SW RBEL
for a COC, the person shall determine the lowest value from paragraphs
(1) - (5) of this subsection for each COC, unless the person has sufficient
surface water quality information specific to the particular surface
water body to support an adjustment to the RBEL in accordance with
paragraph (6) of this subsection. The SW RBEL
value determined pursuant to paragraphs (1) - (6) of this subsection
may require modification in response to the requirements of paragraphs
(7) and (8) of this subsection. TheSW RBEL
value for a given COC shall be protective of relevant downgradient
water bodies in consideration of the water body use (e.g., designated
drinking water supply or sustainable fishery), the water body type
(e.g., estuary or perennial freshwater stream), the standards applicable
to the type of water body/use, and the fate and transport characteristics
of the COC in question at the particular affected property.
(1) The person shall apply the lower of the acute or
chronic criteria for fresh or marine waters as applicable, based on
the classification of the surface water, to protect aquatic life as
provided in §307.6, Table 1 of this title (relating to Toxic
Materials), as amended. The person shall determine the applicability
of aquatic life criteria related to the water body aquatic life use
and flow conditions in accordance with the procedures contained in §§307.3,
307.4, and 307.6 of this title (relating to Definitions and Abbreviations;
General Criteria; and Toxic Materials, respectively), and the agency's Implementation Procedures, as amended, as
defined in §350.4 of this title (relating to Definitions and
Acronyms), as amended. For fresh waters, the person shall calculate
aquatic life criteria for metals with hardness-dependent criteria
using the hardness value for the nearest downstream classified segment,
as listed in the agency's Implementation
Procedures, as amended. Where no value is provided in the Implementation Procedures, a hardness value
of 50 mg/l CaCO3 shall be used. When
applicable, the person shall convert total metal concentrations in
surface water or groundwater to dissolved concentrations as described
in the agency's Implementation Procedures, as
amended. The person may use the basin-specific pH values provided
in §307.6, Table 2 of this title, as amended, relevant to the
particular affected property for purposes of determining the appropriate
values for the pH dependent criteria. The person shall use the total
suspended solids concentration for the nearest classified segment,
as listed in the agency's Implementation
Procedures, as amended.
Cont'd... |
