| biotic
ligand model result may be considered in any public hearing on the
permit application.
(11) Additional site-specific factors may indicate
that the numerical criteria listed in Table 1 of paragraph (1) of
this subsection are inappropriate for a particular water body. These
factors are applied as a site-specific standards modification in accordance
with §307.2(d) of this title (relating to Description of Standards).
The application of a site-specific standard must not impair an existing,
attainable, or designated use. Factors that may justify a temporary
variance or site-specific standards amendment include the following:
(A) background concentrations of specific toxics of
concern in receiving waters, sediment, or indigenous biota;
(B) persistence and degradation rate of specific toxic
materials;
(C) synergistic, additive, or antagonistic interactions
of toxic substances with other toxic or nontoxic materials;
(D) measurements of total effluent toxicity;
(E) indigenous aquatic organisms, which may have different
responses to particular toxic materials;
(F) technological or economic limits of treatability
for specific toxic materials;
(G) bioavailability of specific toxic substances of
concern, as determined by WER tests or other analyses approved by
the commission; and
(H) new information concerning the toxicity of a particular
substance.
(d) Specific numerical human health criteria.
(1) Numerical human health criteria are established
in Table 2 of this paragraph.
Attached Graphic
(2) Categories of human health criteria.
(A) Concentration criteria to prevent contamination
of drinking water, fish, and other aquatic life to ensure that they
are safe for human consumption. These criteria apply to surface waters
that are designated or used for public drinking water supplies, including
all water bodies identified as having a public drinking water supply
use in Appendix A of §307.10 of this title or as a sole-source
surface drinking water supply in Appendix B of §307.10 of this
title. (Column A in Table 2 of paragraph (1) of this subsection.)
(B) Concentration criteria to prevent contamination
of fish and other aquatic life to ensure that they are safe for human
consumption. These criteria apply to surface waters that have sustainable
fisheries and that are not designated or used for public water supply
or as a sole-source surface drinking water supply. (Column B in Table
2 of paragraph (1) of this subsection.)
(3) Specific assumptions and procedures (except where
noted in Table 2 of paragraph (1) of this subsection).
(A) Sources for the toxicity factors to calculate criteria
were derived from EPA's IRIS database; EPA's National
Recommended Water Quality Criteria: 2002, Human Health Criteria Calculation
Matrix (EPA-822-R-02-012); EPA inputs for calculating the 2015
updated national recommended human health criteria; EPA Health Effects
Assessment Summary Tables (HEAST); Assessment Tools for the Evaluation
of Risk (ASTER); EPA's QSAR Toxicity Estimation Software Tool, version
4.1; and the computer program, CLOGP3.
(B) For known or suspected carcinogens (as identified
in EPA's IRIS database), an incremental cancer risk level of 10-5 (1 in 100,000) was used to derive criteria.
An RfD (reference dose) was determined for carcinogens and noncarcinogens
where the EPA has not derived cancer slope factors.
(C) Consumption rates of fish and shellfish were estimated
as 17.5 grams per person per day, unless otherwise specified in Table
2 of paragraph (1) of this subsection.
(D) Drinking water consumption rates were estimated
as 2.0 liters per person per day.
(E) For carcinogens, a body-weight scaling factor of
3/4 power was used to convert data on laboratory test animals to human
scale. Reported weights of laboratory test animals are used, and an
average weight of 70 kilograms is assumed for humans.
(F) Childhood exposure was considered for all noncarcinogens.
Consumption rates for fish and shellfish were estimated as 5.6 grams
per child per day and drinking water consumption rates were estimated
as 0.64 liters per child per day. A child body weight was estimated
at 15 kilograms. Both the water consumption rate and body weight are
age-adjusted for a six-year-old child. The consumption rate for fish
and shellfish for children is from Table 10-61 of EPA's 1997 Exposure
Factors Handbook (EPA/600/P-95/002Fa-c).
(G) Numerical human health criteria were derived in
accordance with the general procedures and calculations in the EPA
guidance documents entitled Technical Support
Document for Water Quality-based Toxics Control (EPA/505/2-90-001); Guidance Manual for Assessing Human Health Risks
from Chemically Contaminated Fish and Shellfish (EPA/503/8-89-002);
and Methodology for Deriving Ambient Water
Quality Criteria for the Protection of Human Health (2000)
(EPA-822-B-00-004).
(H) If a calculated criterion to prevent contamination
of drinking water and fish to ensure they are safe for human consumption
(Column A in Table 2 of paragraph (1) of this subsection) was greater
than the applicable maximum contaminant level (MCL) in Chapter 290
of this title (relating to Public Drinking Water), then the MCL was
used as the criterion.
(I) If the concentration of a substance in fish tissue
used for these calculations was greater than the applicable United
States Food and Drug Administration Action Level for edible fish and
shellfish tissue, then the acceptable concentration in fish tissue
was lowered to the Action Level for calculation of criteria.
(4) Human health criteria for additional toxic materials
are adopted by the commission as appropriate.
(5) Specific human health concentration criteria for
water are applicable to water in the state that has sustainable fisheries
or designation or use as a public drinking water supply or as a sole-source
drinking water supply except within mixing zones and below stream
flow conditions as specified in §307.8 of this title. The following
waters are considered to have sustainable fisheries:
(A) all designated segments listed in Appendix A of
§307.10 of this title, unless specifically exempted;
(B) perennial streams and rivers with a stream order
of three or greater, as defined in §307.3 of this title (relating
to Definitions and Abbreviations);
(C) lakes and reservoirs greater than or equal to 150
acre-feet or 50 surface acres;
(D) all bays, estuaries, and tidal rivers; and
(E) any other waters that potentially have sufficient
fish production or fishing activity to create significant long-term
human consumption of fish.
(6) Waters that are not considered to have a sustainable
fishery, but that have an aquatic life use of limited or greater,
are considered to have an incidental fishery. Consumption rates assumed
for incidental fishery waters are 1.75 grams per person per day. Therefore,
numerical criteria applicable to incidental fishery waters are ten
times the criteria listed in Column B in Table 2 of paragraph (1)
of this subsection.
(7) Specific human health criteria are applied as long
term average exposure criteria designed to protect populations over
a life time. Attainment measures for human health are addressed in
§307.9 of this title.
(8) For toxic materials of concern where specific human
health criteria are not listed in Table 2 of paragraph (1) of this
subsection, the following provisions apply:
(A) For known or suspected carcinogens (as identified
in EPA's IRIS database), a cancer risk of 10-5 (1 in 100,000) is applied
to the most recent numerical criteria adopted by the EPA and published
in the Federal Register. If an MCL or equivalent agency guideline
for protection of drinking water sources is less than the resulting
criterion, then the MCL applies to public drinking water supplies
in accordance with paragraph (3)(H) of this subsection.
(B) For toxic materials not defined as carcinogens,
the most recent numerical criteria adopted by the EPA and published
in the Federal Register are applicable. If an MCL or equivalent agency
guideline for protection of drinking water sources is less than the
resulting criterion, then the MCL applies to public drinking water
supplies in accordance with paragraph (3)(H) of this subsection.
(C) In the absence of available criteria, numerical
criteria may be derived from technically valid information and calculated
in accordance with the provisions of paragraph (3) of this subsection.
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