Notice of Draft Guidance for Implementing the January 2001 Methylmercury Water Quality Criterion, 45560-45564 [06-6803]
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Federal Register / Vol. 71, No. 153 / Wednesday, August 9, 2006 / Notices
iii. Explain why you agree or disagree;
suggest alternatives and substitute
language for your requested changes.
iv. Describe any assumptions and
provide any technical information and/
or data that you used.
v. If you estimate potential costs or
burdens, explain how you arrived at
your estimate in sufficient detail to
allow for it to be reproduced.
vi. Provide specific examples to
illustrate your concerns, and suggest
alternatives.
vii. Explain your views as clearly as
possible, avoiding the use of profanity
or personal threats.
viii. Make sure to submit your
comments by the comment period
deadline identified.
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II. What Action is the Agency Taking?
EPA is printing a summary of each
pesticide petition received under
section 408 of the Federal Food, Drug,
and Cosmetic Act (FFDCA), 21 U.S.C.
346a, proposing the establishment or
amendment of regulations in 40 CFR
part 180 for residues of pesticide
chemicals in or on various food
commodities. EPA has determined that
this pesticide petition contains data or
information regarding the elements set
forth in FFDCA section 408(d)(2);
however, EPA has not fully evaluated
the sufficiency of the submitted data at
this time or whether the data support
granting of the pesticide petition.
Additional data may be needed before
EPA rules on this pesticide petition.
Pursuant to 40 CFR 180.7(f), a
summary of the petition included in this
notice, prepared by the petitioner along
with a description of the analytical
method available for the detection and
measurement of the pesticide chemical
residues is available on EPA’s Electronic
Docket at https://www.regulations.gov/.
To locate this information on the home
page of EPA’s Electronic Docket, select
‘‘Quick Search’’ and type the OPP
docket ID number. Once the search has
located the docket, clicking on the
‘‘Docket ID’’ will bring up a list of all
documents in the docket for the
pesticide including the petition
summary.
1. PP 6E7078. Syngenta Crop
Protection, Inc., P.O. Box 18300,
Greensboro, NC 27410, proposes to
establish an exemption from the
requirement of a tolerance for residues
of the phosphoric acid tris(2-ethyl
hexyl) ester, CAS Reg. No. 78–42–2, in
or on food commodities. Because this
petition is a request for an exemption
from the requirement of a tolerance
without numerical limitations, no
analytical method is required.
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List of Subjects
Environmental protection,
Agricultural commodities, Feed
additives, Food additives, Pesticides
and pests, Reporting and recordkeeping
requirements.
Dated: July 26, 2006.
Lois Rossi,
Director, Registration Division, Office
Pesticide Programs.
[FR Doc. 06–6686 Filed 8–8–06; 8:45 am]
BILLING CODE 6560–50–S
ENVIRONMENTAL PROTECTION
AGENCY
[EPA–HQ–OW–2006–0656, FRL–8207–3]
Notice of Draft Guidance for
Implementing the January 2001
Methylmercury Water Quality Criterion
Environmental Protection
Agency (EPA).
ACTION: Notice of availability and
request for comments.
AGENCY:
SUMMARY: EPA announces the
availability of draft guidance for
implementing the water quality
criterion for methylmercury and
requests comments on the draft
guidance. The draft document provides
technical guidance to states, territories,
and authorized tribes exercising
responsibility under Clean Water Act
(CWA) section 303(c) on how to use
EPA’s fish tissue-based methylmercury
criterion recommendation in developing
their own water quality standards for
methylmercury and in implementing
these standards in Total Maximum
Daily Loads (TMDLs) and National
Pollutant Discharge Elimination System
(NPDES) permits. The guidance
document does not impose any legally
binding requirements on any entity. It
provides various technical and policy
approaches to implementing the
criterion. These approaches are
recommendations only. States,
territories and authorized tribes may
choose to implement other technicallysound approaches that are consistent
with the CWA and EPA’s implementing
regulations.
DATES: Comments must be received on
or before October 10, 2006.
ADDRESSES: Submit your comments,
identified by Docket ID No. EPA–HQ–
OW–2006–0656, by one of the following
methods:
• https://www.regulations.gov: Follow
the on-line instructions for submitting
comments.
• E-mail: ow-docket@epa.gov.
• Mail: Water Docket, Environmental
Protection Agency, Mailcode: 4101T,
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1200 Pennsylvania Ave., NW,
Washington, DC 20460. Please include a
total of four copies.
• Hand Delivery: EPA Docket Center
(EPA/DC), EPA West, Room B102, 1301
Constitution Ave., NW., Washington,
DC 20460. Please include a total of four
copies. Such deliveries are only
accepted during the Docket’s normal
hours of operation, and special
arrangements should be made for
deliveries of boxed information.
Instructions: Direct your comments to
Docket ID No. EPA-HQ-OW–2006–0656.
EPA’s policy is that all comments
received will be included in the public
docket without change and may be
made available online at https://
www.regulations.gov, including any
personal information provided, unless
the comment includes information
claimed to be Confidential Business
Information (CBI) or other information
whose disclosure is restricted by statute.
Do not submit information that you
consider to be CBI or otherwise
protected through https://
www.regulations.gov or owdocket@epa.gov. The https://
www.regulations.gov website is an
‘‘anonymous access’’ system, which
means EPA will not know your identity
or contact information unless you
provide it in the body of your comment.
If you send an e-mail comment directly
to EPA without going through https://
www.regulations.gov your e-mail
address will be automatically captured
and included as part of the comment
that is placed in the public docket and
made available on the Internet. If you
submit an electronic comment, EPA
recommends that you include your
name and other contact information in
the body of your comment and with any
disk or CD-ROM you submit. If EPA
cannot read your comment due to
technical difficulties and cannot contact
you for clarification, EPA may not be
able to consider your comment.
Electronic files should avoid the use of
special characters, any form of
encryption, and be free of any defects or
viruses. For additional information
about EPA’s public docket visit the EPA
Docket Center homepage at https://
www.epa.gov/epahome/dockets.htm.
Docket: All documents in the docket
are listed in the https://
www.regulations.gov index. Although
listed in the index, some information is
not publicly available, e.g., CBI or other
information whose disclosure is
restricted by statute. Certain other
material, such as copyrighted material,
will be publicly available only in hard
copy. Publicly available docket
materials are available either
electronically in https://
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www.regulations.gov or in hard copy at
the Water Docket, EPA/DC, EPA West,
Room B102, 1301 Constitution Ave.,
NW, Washington, DC. The Public
Reading Room is open from 8:30 a.m. to
4:30 p.m., Monday through Friday,
excluding legal holidays. The telephone
number for the Public Reading Room is
(202) 566–1744, and the telephone
number for the Water Docket is (202)
566–2426).
Note: The EPA Docket Center suffered
damage due to flooding during the last week
of June 2006. The Docket Center is
continuing to operate. However, during the
cleanup, there will be temporary changes to
Docket Center telephone numbers, addresses,
and hours of operation for people who wish
to make hand deliveries or visit the Public
Reading Room to view documents. Consult
EPA’s Federal Register notice at 71 FR 38147
(July 5, 2006) or the EPA Web site at
https://www.epa.gov/epahome/dockets.htm
for current information on docket operations,
locations and telephone numbers. The
Docket Center’s mailing address for U.S. mail
and the procedure for submitting comments
to www.regulations.gov are not affected by
the flooding and will remain the same.
Jim
Pendergast, Standards and Health
Protection Division, Office of Water,
(4305T), Environmental Protection
Agency, 1200 Pennsylvania Ave., NW,
Washington, DC, 20460; telephone
number: 202–566–0398; fax number:
202–566–0409; e-mail address:
Pendergast.jim@epa.gov.
FOR FURTHER INFORMATION CONTACT:
SUPPLEMENTARY INFORMATION:
I. General Information
A. Does this Action Apply to Me?
Entities potentially interested in
today’s notice are those that discharge
or release mercury and methylmercury
to surface waters, and federal, state,
tribal, and local authorities that regulate
methylmercury levels in surface water.
Categories and entities interested in
today’s notice include but are not
limited to:
Examples of potentially affected entities
State/Local/Tribal
Government.
Industry .....................
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Category
States, municipalities,
tribes.
Mining, coal-fired
power generation,
other industries
using mercury in
their processing
This table is not intended to be
exhaustive. Other types of entities not
listed in the table may also be
interested.
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B. What Should I Consider as I Prepare
My Comments for EPA?
1. Submitting CBI. Do not submit this
information to EPA through
www.regulations.gov or e-mail. Clearly
mark the part or all of the information
that you claim to be CBI. For CBI
information in a disk or CD ROM that
you mail to EPA, mark the outside of the
disk or CD ROM as CBI and then
identify electronically within the disk or
CD ROM the specific information that is
claimed as CBI). In addition to one
complete version of the comment that
includes information claimed as CBI, a
copy of the comment that does not
contain the information claimed as CBI
must be submitted for inclusion in the
public docket. Information so marked
will not be disclosed except in
accordance with procedures set forth in
40 CFR part 2.
2. Tips for Preparing Your Comments.
When submitting comments, remember
to:
• Identify the docket number and
other identifying information (subject
heading, Federal Register date and page
number).
• Follow directions—The agency may
ask you to respond to specific questions
or organize comments by referencing a
Code of Federal Regulations (CFR) part
or section number.
• Explain why you agree or disagree;
suggest alternatives and substitute
language for your requested changes.
• Describe any assumptions and
provide any technical information and/
or data that you used.
• If you estimate potential costs or
burdens, explain how you arrived at
your estimate in sufficient detail to
allow for it to be reproduced.
• Provide specific examples to
illustrate your concerns, and suggest
alternatives.
• Explain your views as clearly as
possible, avoiding the use of profanity
or personal threats.
• Make sure to submit your
comments by the comment period
deadline identified.
II. Background and Today’s Action
A. What Is Methylmercury and Why Are
We Concerned About It?
Mercury occurs naturally in the
earth’s crust and cycles in the
environment as part of both natural and
human-induced activities. The amount
of mercury mobilized and released into
the biosphere has increased since the
beginning of the industrial age. Most of
the mercury in the atmosphere is
elemental mercury vapor, which
circulates in the atmosphere for up to a
year, and, hence, can be widely
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dispersed and transported thousands of
miles from sources of emission. Most of
the mercury in water, soil, sediments,
plants, and animals is in the form of
inorganic mercury salts and organic
forms of mercury (e.g., methylmercury).
Methylmercury most often results from
microbial activity in wetlands, the water
column, and sediments and is the form
of mercury that presents the greatest risk
to human health. Divalent mercury,
when bound to airborne particles, is
readily removed from the atmosphere by
precipitation and is also dry deposited.
Even after it deposits, mercury
commonly returns to the atmosphere
either as a gas or associated with
particles, and redeposits elsewhere. As
mercury cycles between the atmosphere,
land, and water, mercury undergoes a
series of complex chemical and physical
transformations, many of which are not
completely understood.
Exposure to methylmercury can result
in a variety of health effects in humans.
Children who are exposed to low
concentrations of methylmercury
prenatally might be at risk of poor
performance on neurobehavioral tests,
such as those measuring attention, fine
motor function, language skills, visualspatial abilities, and verbal memory.
(NRC 2000, USEPA 2002, USEPA 2005).
The primary route by which the U.S.
population is exposed to methylmercury
is through the consumption of fish
containing methylmercury. For most
people, methylmercury exposure from
consumption of fish and shellfish is not
a health concern. Yet, the exposure
levels at which neurological effects have
been observed in children can occur via
maternal consumption of fish (rather
than high-dose poisoning episodes)
(USEPA 2005). The risks from
methylmercury in fish and shellfish
depend on the amount of fish and
shellfish eaten and the levels of
methylmercury in the fish and shellfish.
Therefore, the Food and Drug
Administration (FDA) and the
Environmental Protection Agency (EPA)
are advising women who may become
pregnant, pregnant women, nursing
mothers, and young children to avoid
some types of fish and eat fish and
shellfish that are lower in
methylmercury. You can find more
information about this joint Federal
advisory on EPA’s Web site at https://
www.epa.gov/waterscience/fish.
In 2000, the National Academy of
Sciences (NAS)/National Research
Council (NRC) reviewed the health
studies on methylmercury (NRC 2000).
In its review of the literature, NRC
found neurodevelopmental effects to be
the most sensitive endpoints and
appropriate for establishing a
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methylmercury Reference Dose (RfD)
(NRC 2000). EPA defines an RfD as ‘‘an
estimate (with uncertainty spanning
perhaps an order of magnitude) of a
daily oral exposure to the human
population (including sensitive
subgroups) that is likely to be without
an appreciable risk of deleterious effects
during a lifetime. On the basis of the
NRC report, EPA established an RfD of
0.0001 mg/kg per day (0.0001 milligram
of methylmercury per day for each
kilogram of a person’s body mass) in
2001 (USEPA 2002). EPA believes that
exposures at or below the RfD are
unlikely to be associated with
appreciable risk of deleterious effects. It
is important to note, however, that the
RfD does not define an exposure level
corresponding to zero risk;
methylmercury exposure near or below
the RfD could pose a very low level of
risk that EPA deems to be nonappreciable. It is also important to note
that the RfD does not define a bright
line, above which individuals are at risk
of adverse effects (USEPA 2005). NAS
determined that EPA’s RfD ‘‘is a
scientifically justified level for the
protection of public health.’’
With regard to other health effects of
methylmercury, some recent
epidemiological studies in men suggest
that methylmercury is associated with a
higher risk of acute myocardial
infarction, coronary heart disease, and
cardiovascular disease in some
populations. Other recent studies have
not observed this association. The
studies that have observed an
association suggest that the exposure to
methylmercury might attenuate the
beneficial effects of fish consumption
(USEPA 2005). There also is some
recent evidence that exposures of
methylmercury might result in
genotoxic or immunotoxic effects. Other
research with less corroboration
suggests that reproductive, renal, and
hematological impacts could be of
concern. There are insufficient human
data to evaluate whether these effects
are consistent with methylmercury
exposure levels in the U.S. population
(USEPA 2005).
B. What Is the Current Methylmercury
Criterion?
In a January 8, 2001, Federal Register
notice (66 FR 1344), EPA announced the
availability of its recommended water
quality criterion for methylmercury. The
methylmercury water quality criterion is
derived from the methylmercury RfD
(described above) and data about the
target population to be protected (i.e.,
exposure parameters and assumptions).
The equation for calculating the
methylmercury fish tissue residue water
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quality criterion for the protection of
human health is:
TRC =
BW × ( RfD − RSC )
4
∑ FI
i
i=2
Where:
TRC = Fish tissue residue criterion (mg
methylmercury/kg fish tissue) for
freshwater and estuarine fish and
shellfish
RfD = Reference Dose (based on non-cancer
human health effects). For
methylmercury the RfD is 0.0001 mg/kg
BW-day (0.1 ug/kg BW-day)
RSC = Relative source contribution
(subtracted from the RfD to account for
marine fish consumption) estimated to
be 2.7 x 10–5 mg/kg BW-day
BW = Human body weight default value of
70kg (for adults)
FI = Fish intake at trophic level (TL) i (i =
2, 3, 4); total default intake is 0.0175 kg
fish/day for general adult population.
Trophic level breakouts for the general
population are: TL2 = 0.0038 kg fish/day;
TL3 = 0.0080 kg fish/day; and TL4 =
0.0057 kg fish/day.
This equation and all values used in
the equation are described in Water
Quality Criterion for the Protection of
Human Health, Methylmercury (USEPA
2001b). This equation is essentially the
same equation used in the 2000 Human
Health Methodology to calculate a water
quality criterion for a pollutant that may
cause non-cancer health effects, but is
rearranged to solve for a protective
concentration in fish tissue rather than
in water. Thus, the equation does not
include a bioaccumulation factor (BAF)
or drinking water intake value
(methylmercury exposure from drinking
water is negligible (USEPA 2001a)).
Incorporating the relevant values into
the above equation, EPA obtained a fish
tissue concentration (TRC) of 0.3 mg
methylmercury/kg fish as the
concentration in fish tissue that should
not be exceeded. EPA’s preference is for
states and authorized tribes to use local
or regional consumption rates, if these
would better reflect the target
populations.
C. What Is The Draft Implementation
Guidance?
In the 2001 Federal Register notice of
the availability of EPA’s recommended
water quality criterion for
methylmercury, EPA stated that it
would develop associated procedures
and guidance for implementing the
criterion. We are issuing that draft
guidance today. The guidance will assist
states in developing a water quality
criterion for methylmercury in their
water quality standards. States can
either adopt EPA’s recommended
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criterion or another criterion that is
scientifically defensible and consistent
with the Act and its implementing
regulations. 40 CFR 131.11(a)(2).
This guidance document presents
suggested approaches to criteria
adoption and implementation. These
approaches are recommendations and
do not represent the only technically
defensible approaches. The discussion
in the guidance document is intended
solely as guidance. This guidance does
not change or, substitute for, applicable
sections of the CWA or EPA’s
regulations; nor is it a regulation itself.
Thus, it does not impose legally binding
requirements on EPA, states, authorized
tribes, or the regulated community and
may not apply to a particular situation.
EPA, state, territorial, and tribal
decision makers retain the discretion to
adopt approaches on a case-by-case
basis that differ from this guidance
where appropriate.
D. Why Did EPA Draft This Guidance?
The methylmercury criterion is
expressed as a fish and shellfish tissue
value, and this raises both technical and
programmatic implementation
questions. EPA expects that, as a result
of the revised methylmercury water
quality criterion, together with a more
sensitive method for detecting mercury
in effluent and the water column, and
increased monitoring of previously
unmonitored waterbodies, the number
of waterbodies that states report on
CWA section 303(d) lists as impaired
due to methylmercury contamination
might continue to increase.
Development of water quality standards,
NPDES permits, and TMDLs present
challenges because these activities
typically have been based on a water
concentration (e.g., as a measure of
mercury levels in effluent). This
guidance addresses issues associated
with states and authorized tribes
adopting the new water quality criterion
into their water quality standards
programs and implementation of the
revised water quality criterion in
TMDLs and NPDES permits. Further,
because atmospheric deposition serves
as a large source of mercury for many
waterbodies, implementation of the
criterion involves coordination across
various media and program areas.
E. What Does the Draft Guidance
Recommend?
For states and authorized tribes
exercising responsibility under CWA
section 303(c), this document provides
technical guidance on how they might
want to use the recommended 2001 fish
tissue-based criterion to develop their
own water quality standards for
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methylmercury. States and authorized
tribes may decide to adopt the EPA
recommended methylmercury fish
tissue-based criterion based on the
national default fish consumption rate
or translate the tissue value to a water
column value through use of
methylmercury BAFs. If a state or
authorized tribe decides to translate the
fish tissue criterion to a water column
criterion, EPA recommends three
approaches for relating a concentration
of methylmercury in fish tissue to a
concentration of methylmercury in
ambient water: (1) Deriving site-specific
methylmercury BAFs; (2) using
bioaccumulation models; and (3) using
EPA’s draft default methylmercury
BAFs. All three approaches have
limitations, such as the amount of data
necessary to develop a BAF. This
guidance discusses the advantages and
limitations of each approach.
States and authorized tribes may also
consider calculating their own fish
tissue criteria or adopting site-specific
criteria for methylmercury to reflect
local or regional fish consumption rates
or relative source contributions. This
guidance also discusses variances and
use attainability analyses relating to
methylmercury.
This document describes analytical
methods for determining the
concentrations of mercury and
methylmercury in both tissue and water.
These methods can detect mercury and
methylmercury in tissue and water at
very low levels—well below the levels
of the previous criterion for mercury in
the water column and the current
criterion of methylmercury in fish
tissue. This document also provides
guidance for field sampling plans,
laboratory analysis protocols, and data
interpretation that is based on
previously published EPA guidance on
sampling strategies for contaminant
monitoring. This guidance also
describes how states can assess the
attainment of water quality criteria and
protection of designated uses by
comparing sampling data to water
quality criteria.
This guidance also discusses
approaches for the development of
TMDLs for waterbodies impaired by
mercury. This includes approaches for
TMDLs for waterbodies where much of
the mercury is from atmospheric
sources and suggestions regarding how
such TMDLs can take into account
ongoing efforts to address sources of
mercury, such as programs under the
Clean Air Act (CAA) and pollution
prevention activities.
EPA’s Technical Support Document
for Water Quality-based Toxics Control
(TSD), EPA 505/2–90–001, explains
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how to implement criteria expressed in
terms of pollutant concentrations in
water in NPDES permits. States that
decide to implement the methylmercury
tissue criterion as a water concentration
for NPDES permits should continue to
use the TSD guidance. However, for
states that decide to implement the
methylmercury tissue criterion directly,
that is, without translating it into a
water column value, the TSD doesn’t
provide relevant guidance. Today’s draft
guidance also includes a recommended
approach for directly incorporating the
methylmercury tissue criterion in
NPDES permits.
authority could reasonably conclude
that reasonable potential exists if two
conditions are present (1) The NPDES
permitted discharger has mercury in its
effluent at a quantifiable level and (2)
fish tissue from the waterbody into
which the discharger discharges exceeds
the fish tissue water quality criterion.
EPA specifically solicits comment on
alternate methods, based on using other
information, for determining that there
is reasonable potential to exceed the
water quality standard where fish tissue
data show that the methylmercury
tissue criterion in a water quality
standard is achieved.
F. Are There Particular Issues on Which
EPA is Requesting Comment?
EPA requests comments only on the
draft methylmercury criterion
implementation guidance. EPA is not
requesting comments on the 2001
methylmercury criterion itself.
Although EPA solicits comment on the
entire draft guidance, it is particularly
interested in the following topics:
2. Applying Water Quality Variances on
a Watershed or State-Wide Basis
Traditionally, states establish water
quality variances that are specific to a
pollutant and a facility. EPA recognizes
that, for mercury, there are situations
where a number of NPDES dischargers
are located in the same area or
watershed and the justification
supporting granting a variance applies
to all of the dischargers. Two states,
Ohio and Michigan, have already
developed variances that apply to
multiple discharges for mercury.
Today’s guidance encourages states and
authorized tribes to consider
establishing a multiple-discharger
variance for a group of dischargers
collectively.
EPA solicits comment on whether it
should discuss multi-discharge,
watershed, or state-wide variances in
the final guidance.
1. Implementation Approach for NPDES
Permits Where the Criterion Is
Implemented as a Fish Tissue Value
Today’s guidance presents a
recommended approach for directly
incorporating the methylmercury tissue
criterion in NPDES permits. This
approach does not rely upon a state
developing a bioaccumulation factor to
convert the methylmercury tissue
criterion into a water concentration
equivalent. The approach recommends
that facilities that use, accept or receive
mercury into their wastewaters develop
mercury minimization plans. For
discharges that are small contributors of
mercury to a watershed or do not use
mercury in their processes, the
approach recommends that current
permit effluent levels remain constant.
EPA expects that most facilities will fall
into this category due to significant
loadings from other sources (e.g., air
deposition, abandoned mines). For
discharges that are significant
contributors of mercury to a watershed
and use mercury in their processes, the
approach recommends that permit
effluent limits ensure the attainment of
water quality standards. EPA expects
that few dischargers should fall into this
category. For new or increased
discharges, the approach recommends
that permit effluent limits hold
watershed loadings constant using
antidegradation principles.
EPA solicits comment on the
recommendations for directly
incorporating the methylmercury tissue
criterion in NPDES permits. The draft
guidance recommends that a permitting
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G. References Cited
NRC (National Research Council). 2000.
Toxicological effects of methylmercury.
Committee on the Toxicological Effects of
Methylmercury. National Academy Press.
Washington, DC.
USEPA (U.S. Environmental Protection
Agency). 1991. Technical Support
Document for Water Quality-based Toxics
Control. EPA 505/2–90–001. U.S.
Environmental Protection Agency, Office
of Water Enforcement and Permits and
Office of Water Regulations and Standards.
USEPA (U.S. Environmental Protection
Agency). 2001a. Water quality criteria:
Notice of Availability of water quality
criterion for the protection of human
health: Methylmercury. U.S.
Environmental Protection Agency, Office
of Water, Washington, DC. Fed. Regist.,
66:1344.
USEPA (U.S. Environmental Protection
Agency). 2001b. Water quality criterion for
the protection of human health:
Methylmercury. EPA–823–R–01–001. U.S.
Environmental Protection Agency, Office
of Water, Washington, DC.
USEPA (U.S. Environmental Protection
Agency). 2002. Integrated Risk Information
System (IRIS). Methylmercury. U.S.
Environmental Protection Agency, Office
E:\FR\FM\09AUN1.SGM
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Federal Register / Vol. 71, No. 153 / Wednesday, August 9, 2006 / Notices
of Research and Development, National
Center for Environmental Assessment.
USEPA (U.S. Environmental Protection
Agency). 2005. Regulatory Impact Analysis
of the Clean Air Mercury Rule. Final
Report. EPA–452/R–05–003. U.S.
Environmental Protection Agency, Office
of Air Quality Planning and Standards, Air
Quality Strategies and Standards Division,
Research Triangle Park, NC.
the description of the service area; and
the date and time of the
recommendation. If a conflict in
recommendations arises, the affected
coordinators are jointly responsible for
taking action to resolve the conflict, up
to and including notifying the
Commission that an application may
have to be returned.
Dated: August 3, 2006.
Benjamin H. Grumbles,
Assistant Administrator for Water.
[FR Doc. 06–6803 Filed 8–8–06; 8:45 am]
Federal Communications Commission.
Jacqueline R. Coles,
Associate Secretary.
[FR Doc. E6–12993 Filed 8–8–06; 8:45 am]
BILLING CODE 6560–50–P
BILLING CODE 6712–01–P
FEDERAL COMMUNICATIONS
COMMISSION
FEDERAL COMMUNICATIONS
COMMISSION
Public Information Collections
Approved by Office of Management
and Budget
Public Information Collections
Approved by Office of Management
and Budget
August 1, 2006.
August 3, 2006.
The Federal Communications
Commission (FCC) has received Office
of Management and Budget (OMB)
approval for the following public
information collections pursuant to the
Paperwork Reduction Act of 1995,
Public Law 104–13. An agency may not
conduct or sponsor and a person is not
required to respond to a collection of
information unless it displays a
currently valid control number.
FOR FURTHER INFORMATION CONTACT:
Zenji Nakazawa, Federal
Communications Commission, 445 12th
Street, SW., Washington, DC 20554,
(202) 418–0600 or via the Internet at
Zenji.Nakazawa@fcc.gov.
SUPPLEMENTARY INFORMATION:
OMB Control No.: 3060–0783.
OMB Approval date: January 31, 2006.
Expiration Date: January 31, 2009.
Title: Section 90.176, Coordinator
notification requirements on frequencies
below 512 MHz or at 764–776/794–806
MHz.
Form No.: N/A.
Estimated Annual Burden: 3,900
responses; 1,950 total annual burden
hours; .50 hours average per respondent.
Needs and Uses: Section 90.176
requires each Private Land Mobile
frequency coordinator to provide,
within one business day, a listing of
their frequency recommendations to all
other frequency coordinators in their
respective pool, and, if requested, an
engineering analysis. Any method can
be used to ensure this compliance with
the ‘‘one business day requirement’’ and
must provide, at a minimum, the name
of the applicant; frequency or
frequencies recommended; antenna
locations and heights; the effective
radiated power; the type(s) of emission;
jlentini on PROD1PC65 with NOTICES
SUMMARY:
VerDate Aug<31>2005
19:05 Aug 08, 2006
Jkt 208001
SUMMARY: The Federal Communications
Commission (Commission) has received
Office of Management and Budget
(OMB) approval for the following public
information collections pursuant to the
Paperwork Reduction Act of 1995,
Public Law 104–13. An agency may not
conduct or sponsor and a person is not
required to respond to a collection of
information unless it displays a
currently valid control number.
FOR FURTHER INFORMATION CONTACT: Paul
J. Laurenzano, Federal Communications
Commission, 445 12th Street, SW.,
Washington, DC 20554, (202) 418–1359
or via the Internet at plaurenz@fcc.gov.
SUPPLEMENTARY INFORMATION:
OMB Control No.: 3060–0855.
OMB Approval Date: 7/27/2006.
Expiration Date: 1/31/2007.
Title: Telecommunications Reporting
Worksheet, WC Docket No. 06–112, CC
Docket No. 96–45.
Form No.: FCC Forms 499 (FCC Forms
499–A and 499–Q).
Estimated Annual Burden: 17,465
responses; 263,230 total annual burden
hours; 10–25 hours per quarterly filing
and 13.5–25 hours per annual filing per
respondent.
Needs and Uses: This collection was
submitted as a revision to an existing
collection to obtain emergency
clearance for FCC Forms 499–A and
499–Q (3060–0855). Universal Service
obligations have been extended to
interconnected Voice over Internet
Protocol (interconnected VoIP)
providers. The Commission requires
telecommunications carriers and certain
other providers of interstate
telecommunications to contribute to the
universal service fund. The Commission
has found that interconnected VoIP
PO 00000
Frm 00049
Fmt 4703
Sfmt 4703
providers are providers of interstate
telecommunications. As such, the
Commission has determined that
interconnected VoIP providers must
contribute to the universal service fund.
By including interconnected VoIP
providers in the contribution base, the
Commission ensures that its
contribution mechanism remains
equitable, nondiscriminatory, and
competitively neutral. The Commission
determined that interconnected VoIP
providers may contribute based on an
interim safe harbor amount, under
which interconnected VoIP providers
treat 64.9 percent of their
telecommunications revenues as
interstate; their actual interstate enduser telecommunications revenues; or
an estimate of their interstate end-user
telecommunications revenues as
determined by a traffic study, which
must first be submitted to, then
affirmatively approved by, the
Commission. In addition, the
Commission revised the interim
wireless safe harbor that wireless
providers may use to report their
interstate revenues to 37.1 percent. The
Commission also determined that, to the
extent wireless providers report
interstate telecommunications revenue
based on traffic studies, in lieu of
reporting revenues based on actual
interstate end-user telecommunications
revenues or based on the interim
wireless safe harbor of 37.1 percent,
such traffic studies must be filed with
the Commission and the Universal
Service Administrative Company.
OMB Control No.: 3060–0859.
OMB Approval Date: 6/23/2006.
Expiration Date: 6/30/2009.
Title: Suggested Guidelines for
Petitons for Ruling Under Section 253 of
the Communications Act.
Form No.: N/A.
Estimated Annual Burden: 80
Responses; 6,280 total annual burden
hours; 63–125 hours per respondent.
Needs and Uses: This collection was
submitted to extend an existing
collection. The collection establishes
various procedural guidelines related to
the Commission’s processing of
petitions for preemption pursuant to
Section 253 of the Communications Act
of 1934, as amended. The Commission
uses the information to discharge its
statutory mandate relating to the
preemption of state or local statutes or
other state or local legal requirements.
Federal Communications Commission.
Jacqueline R. Coles,
Associate Secretary.
[FR Doc. E6–12994 Filed 8–8–06; 8:45 am]
BILLING CODE 6712–01–P
E:\FR\FM\09AUN1.SGM
09AUN1
Agencies
[Federal Register Volume 71, Number 153 (Wednesday, August 9, 2006)]
[Notices]
[Pages 45560-45564]
From the Federal Register Online via the Government Printing Office [www.gpo.gov]
[FR Doc No: 06-6803]
-----------------------------------------------------------------------
ENVIRONMENTAL PROTECTION AGENCY
[EPA-HQ-OW-2006-0656, FRL-8207-3]
Notice of Draft Guidance for Implementing the January 2001
Methylmercury Water Quality Criterion
AGENCY: Environmental Protection Agency (EPA).
ACTION: Notice of availability and request for comments.
-----------------------------------------------------------------------
SUMMARY: EPA announces the availability of draft guidance for
implementing the water quality criterion for methylmercury and requests
comments on the draft guidance. The draft document provides technical
guidance to states, territories, and authorized tribes exercising
responsibility under Clean Water Act (CWA) section 303(c) on how to use
EPA's fish tissue-based methylmercury criterion recommendation in
developing their own water quality standards for methylmercury and in
implementing these standards in Total Maximum Daily Loads (TMDLs) and
National Pollutant Discharge Elimination System (NPDES) permits. The
guidance document does not impose any legally binding requirements on
any entity. It provides various technical and policy approaches to
implementing the criterion. These approaches are recommendations only.
States, territories and authorized tribes may choose to implement other
technically-sound approaches that are consistent with the CWA and EPA's
implementing regulations.
DATES: Comments must be received on or before October 10, 2006.
ADDRESSES: Submit your comments, identified by Docket ID No. EPA-HQ-OW-
2006-0656, by one of the following methods:
https://www.regulations.gov: Follow the on-line
instructions for submitting comments.
E-mail: ow-docket@epa.gov.
Mail: Water Docket, Environmental Protection Agency,
Mailcode: 4101T, 1200 Pennsylvania Ave., NW, Washington, DC 20460.
Please include a total of four copies.
Hand Delivery: EPA Docket Center (EPA/DC), EPA West, Room
B102, 1301 Constitution Ave., NW., Washington, DC 20460. Please include
a total of four copies. Such deliveries are only accepted during the
Docket's normal hours of operation, and special arrangements should be
made for deliveries of boxed information.
Instructions: Direct your comments to Docket ID No. EPA-HQ-OW-2006-
0656. EPA's policy is that all comments received will be included in
the public docket without change and may be made available online at
https://www.regulations.gov, including any personal information
provided, unless the comment includes information claimed to be
Confidential Business Information (CBI) or other information whose
disclosure is restricted by statute. Do not submit information that you
consider to be CBI or otherwise protected through https://
www.regulations.gov or ow-docket@epa.gov. The https://
www.regulations.gov website is an ``anonymous access'' system, which
means EPA will not know your identity or contact information unless you
provide it in the body of your comment. If you send an e-mail comment
directly to EPA without going through https://www.regulations.gov your
e-mail address will be automatically captured and included as part of
the comment that is placed in the public docket and made available on
the Internet. If you submit an electronic comment, EPA recommends that
you include your name and other contact information in the body of your
comment and with any disk or CD-ROM you submit. If EPA cannot read your
comment due to technical difficulties and cannot contact you for
clarification, EPA may not be able to consider your comment. Electronic
files should avoid the use of special characters, any form of
encryption, and be free of any defects or viruses. For additional
information about EPA's public docket visit the EPA Docket Center
homepage at https://www.epa.gov/epahome/dockets.htm.
Docket: All documents in the docket are listed in the https://
www.regulations.gov index. Although listed in the index, some
information is not publicly available, e.g., CBI or other information
whose disclosure is restricted by statute. Certain other material, such
as copyrighted material, will be publicly available only in hard copy.
Publicly available docket materials are available either electronically
in https://
[[Page 45561]]
www.regulations.gov or in hard copy at the Water Docket, EPA/DC, EPA
West, Room B102, 1301 Constitution Ave., NW, Washington, DC. The Public
Reading Room is open from 8:30 a.m. to 4:30 p.m., Monday through
Friday, excluding legal holidays. The telephone number for the Public
Reading Room is (202) 566-1744, and the telephone number for the Water
Docket is (202) 566-2426).
Note: The EPA Docket Center suffered damage due to flooding
during the last week of June 2006. The Docket Center is continuing
to operate. However, during the cleanup, there will be temporary
changes to Docket Center telephone numbers, addresses, and hours of
operation for people who wish to make hand deliveries or visit the
Public Reading Room to view documents. Consult EPA's Federal
Register notice at 71 FR 38147 (July 5, 2006) or the EPA Web site at
https://www.epa.gov/epahome/dockets.htm for current information on
docket operations, locations and telephone numbers. The Docket
Center's mailing address for U.S. mail and the procedure for
submitting comments to www.regulations.gov are not affected by the
flooding and will remain the same.
FOR FURTHER INFORMATION CONTACT: Jim Pendergast, Standards and Health
Protection Division, Office of Water, (4305T), Environmental Protection
Agency, 1200 Pennsylvania Ave., NW, Washington, DC, 20460; telephone
number: 202-566-0398; fax number: 202-566-0409; e-mail address:
Pendergast.jim@epa.gov.
SUPPLEMENTARY INFORMATION:
I. General Information
A. Does this Action Apply to Me?
Entities potentially interested in today's notice are those that
discharge or release mercury and methylmercury to surface waters, and
federal, state, tribal, and local authorities that regulate
methylmercury levels in surface water. Categories and entities
interested in today's notice include but are not limited to:
------------------------------------------------------------------------
Examples of potentially
Category affected entities
------------------------------------------------------------------------
State/Local/Tribal Government............. States, municipalities,
tribes.
Industry.................................. Mining, coal-fired power
generation, other
industries using mercury in
their processing
------------------------------------------------------------------------
This table is not intended to be exhaustive. Other types of
entities not listed in the table may also be interested.
B. What Should I Consider as I Prepare My Comments for EPA?
1. Submitting CBI. Do not submit this information to EPA through
www.regulations.gov or e-mail. Clearly mark the part or all of the
information that you claim to be CBI. For CBI information in a disk or
CD ROM that you mail to EPA, mark the outside of the disk or CD ROM as
CBI and then identify electronically within the disk or CD ROM the
specific information that is claimed as CBI). In addition to one
complete version of the comment that includes information claimed as
CBI, a copy of the comment that does not contain the information
claimed as CBI must be submitted for inclusion in the public docket.
Information so marked will not be disclosed except in accordance with
procedures set forth in 40 CFR part 2.
2. Tips for Preparing Your Comments. When submitting comments,
remember to:
Identify the docket number and other identifying
information (subject heading, Federal Register date and page number).
Follow directions--The agency may ask you to respond to
specific questions or organize comments by referencing a Code of
Federal Regulations (CFR) part or section number.
Explain why you agree or disagree; suggest alternatives
and substitute language for your requested changes.
Describe any assumptions and provide any technical
information and/or data that you used.
If you estimate potential costs or burdens, explain how
you arrived at your estimate in sufficient detail to allow for it to be
reproduced.
Provide specific examples to illustrate your concerns, and
suggest alternatives.
Explain your views as clearly as possible, avoiding the
use of profanity or personal threats.
Make sure to submit your comments by the comment period
deadline identified.
II. Background and Today's Action
A. What Is Methylmercury and Why Are We Concerned About It?
Mercury occurs naturally in the earth's crust and cycles in the
environment as part of both natural and human-induced activities. The
amount of mercury mobilized and released into the biosphere has
increased since the beginning of the industrial age. Most of the
mercury in the atmosphere is elemental mercury vapor, which circulates
in the atmosphere for up to a year, and, hence, can be widely dispersed
and transported thousands of miles from sources of emission. Most of
the mercury in water, soil, sediments, plants, and animals is in the
form of inorganic mercury salts and organic forms of mercury (e.g.,
methylmercury). Methylmercury most often results from microbial
activity in wetlands, the water column, and sediments and is the form
of mercury that presents the greatest risk to human health. Divalent
mercury, when bound to airborne particles, is readily removed from the
atmosphere by precipitation and is also dry deposited. Even after it
deposits, mercury commonly returns to the atmosphere either as a gas or
associated with particles, and redeposits elsewhere. As mercury cycles
between the atmosphere, land, and water, mercury undergoes a series of
complex chemical and physical transformations, many of which are not
completely understood.
Exposure to methylmercury can result in a variety of health effects
in humans. Children who are exposed to low concentrations of
methylmercury prenatally might be at risk of poor performance on
neurobehavioral tests, such as those measuring attention, fine motor
function, language skills, visual-spatial abilities, and verbal memory.
(NRC 2000, USEPA 2002, USEPA 2005). The primary route by which the U.S.
population is exposed to methylmercury is through the consumption of
fish containing methylmercury. For most people, methylmercury exposure
from consumption of fish and shellfish is not a health concern. Yet,
the exposure levels at which neurological effects have been observed in
children can occur via maternal consumption of fish (rather than high-
dose poisoning episodes) (USEPA 2005). The risks from methylmercury in
fish and shellfish depend on the amount of fish and shellfish eaten and
the levels of methylmercury in the fish and shellfish. Therefore, the
Food and Drug Administration (FDA) and the Environmental Protection
Agency (EPA) are advising women who may become pregnant, pregnant
women, nursing mothers, and young children to avoid some types of fish
and eat fish and shellfish that are lower in methylmercury. You can
find more information about this joint Federal advisory on EPA's Web
site at https://www.epa.gov/waterscience/fish.
In 2000, the National Academy of Sciences (NAS)/National Research
Council (NRC) reviewed the health studies on methylmercury (NRC 2000).
In its review of the literature, NRC found neurodevelopmental effects
to be the most sensitive endpoints and appropriate for establishing a
[[Page 45562]]
methylmercury Reference Dose (RfD) (NRC 2000). EPA defines an RfD as
``an estimate (with uncertainty spanning perhaps an order of magnitude)
of a daily oral exposure to the human population (including sensitive
subgroups) that is likely to be without an appreciable risk of
deleterious effects during a lifetime. On the basis of the NRC report,
EPA established an RfD of 0.0001 mg/kg per day (0.0001 milligram of
methylmercury per day for each kilogram of a person's body mass) in
2001 (USEPA 2002). EPA believes that exposures at or below the RfD are
unlikely to be associated with appreciable risk of deleterious effects.
It is important to note, however, that the RfD does not define an
exposure level corresponding to zero risk; methylmercury exposure near
or below the RfD could pose a very low level of risk that EPA deems to
be non-appreciable. It is also important to note that the RfD does not
define a bright line, above which individuals are at risk of adverse
effects (USEPA 2005). NAS determined that EPA's RfD ``is a
scientifically justified level for the protection of public health.''
With regard to other health effects of methylmercury, some recent
epidemiological studies in men suggest that methylmercury is associated
with a higher risk of acute myocardial infarction, coronary heart
disease, and cardiovascular disease in some populations. Other recent
studies have not observed this association. The studies that have
observed an association suggest that the exposure to methylmercury
might attenuate the beneficial effects of fish consumption (USEPA
2005). There also is some recent evidence that exposures of
methylmercury might result in genotoxic or immunotoxic effects. Other
research with less corroboration suggests that reproductive, renal, and
hematological impacts could be of concern. There are insufficient human
data to evaluate whether these effects are consistent with
methylmercury exposure levels in the U.S. population (USEPA 2005).
B. What Is the Current Methylmercury Criterion?
In a January 8, 2001, Federal Register notice (66 FR 1344), EPA
announced the availability of its recommended water quality criterion
for methylmercury. The methylmercury water quality criterion is derived
from the methylmercury RfD (described above) and data about the target
population to be protected (i.e., exposure parameters and assumptions).
The equation for calculating the methylmercury fish tissue residue
water quality criterion for the protection of human health is:
[GRAPHIC] [TIFF OMITTED] TN09AU06.006
Where:
TRC = Fish tissue residue criterion (mg methylmercury/kg fish
tissue) for freshwater and estuarine fish and shellfish
RfD = Reference Dose (based on non-cancer human health effects). For
methylmercury the RfD is 0.0001 mg/kg BW-day (0.1 ug/kg BW-day)
RSC = Relative source contribution (subtracted from the RfD to
account for marine fish consumption) estimated to be 2.7 x 10-5 mg/
kg BW-day
BW = Human body weight default value of 70kg (for adults)
FI = Fish intake at trophic level (TL) i (i = 2, 3, 4); total
default intake is 0.0175 kg fish/day for general adult population.
Trophic level breakouts for the general population are: TL2 = 0.0038
kg fish/day; TL3 = 0.0080 kg fish/day; and TL4 = 0.0057 kg fish/day.
This equation and all values used in the equation are described in
Water Quality Criterion for the Protection of Human Health,
Methylmercury (USEPA 2001b). This equation is essentially the same
equation used in the 2000 Human Health Methodology to calculate a water
quality criterion for a pollutant that may cause non-cancer health
effects, but is rearranged to solve for a protective concentration in
fish tissue rather than in water. Thus, the equation does not include a
bioaccumulation factor (BAF) or drinking water intake value
(methylmercury exposure from drinking water is negligible (USEPA
2001a)). Incorporating the relevant values into the above equation, EPA
obtained a fish tissue concentration (TRC) of 0.3 mg methylmercury/kg
fish as the concentration in fish tissue that should not be exceeded.
EPA's preference is for states and authorized tribes to use local or
regional consumption rates, if these would better reflect the target
populations.
C. What Is The Draft Implementation Guidance?
In the 2001 Federal Register notice of the availability of EPA's
recommended water quality criterion for methylmercury, EPA stated that
it would develop associated procedures and guidance for implementing
the criterion. We are issuing that draft guidance today. The guidance
will assist states in developing a water quality criterion for
methylmercury in their water quality standards. States can either adopt
EPA's recommended criterion or another criterion that is scientifically
defensible and consistent with the Act and its implementing
regulations. 40 CFR 131.11(a)(2).
This guidance document presents suggested approaches to criteria
adoption and implementation. These approaches are recommendations and
do not represent the only technically defensible approaches. The
discussion in the guidance document is intended solely as guidance.
This guidance does not change or, substitute for, applicable sections
of the CWA or EPA's regulations; nor is it a regulation itself. Thus,
it does not impose legally binding requirements on EPA, states,
authorized tribes, or the regulated community and may not apply to a
particular situation. EPA, state, territorial, and tribal decision
makers retain the discretion to adopt approaches on a case-by-case
basis that differ from this guidance where appropriate.
D. Why Did EPA Draft This Guidance?
The methylmercury criterion is expressed as a fish and shellfish
tissue value, and this raises both technical and programmatic
implementation questions. EPA expects that, as a result of the revised
methylmercury water quality criterion, together with a more sensitive
method for detecting mercury in effluent and the water column, and
increased monitoring of previously unmonitored waterbodies, the number
of waterbodies that states report on CWA section 303(d) lists as
impaired due to methylmercury contamination might continue to increase.
Development of water quality standards, NPDES permits, and TMDLs
present challenges because these activities typically have been based
on a water concentration (e.g., as a measure of mercury levels in
effluent). This guidance addresses issues associated with states and
authorized tribes adopting the new water quality criterion into their
water quality standards programs and implementation of the revised
water quality criterion in TMDLs and NPDES permits. Further, because
atmospheric deposition serves as a large source of mercury for many
waterbodies, implementation of the criterion involves coordination
across various media and program areas.
E. What Does the Draft Guidance Recommend?
For states and authorized tribes exercising responsibility under
CWA section 303(c), this document provides technical guidance on how
they might want to use the recommended 2001 fish tissue-based criterion
to develop their own water quality standards for
[[Page 45563]]
methylmercury. States and authorized tribes may decide to adopt the EPA
recommended methylmercury fish tissue-based criterion based on the
national default fish consumption rate or translate the tissue value to
a water column value through use of methylmercury BAFs. If a state or
authorized tribe decides to translate the fish tissue criterion to a
water column criterion, EPA recommends three approaches for relating a
concentration of methylmercury in fish tissue to a concentration of
methylmercury in ambient water: (1) Deriving site-specific
methylmercury BAFs; (2) using bioaccumulation models; and (3) using
EPA's draft default methylmercury BAFs. All three approaches have
limitations, such as the amount of data necessary to develop a BAF.
This guidance discusses the advantages and limitations of each
approach.
States and authorized tribes may also consider calculating their
own fish tissue criteria or adopting site-specific criteria for
methylmercury to reflect local or regional fish consumption rates or
relative source contributions. This guidance also discusses variances
and use attainability analyses relating to methylmercury.
This document describes analytical methods for determining the
concentrations of mercury and methylmercury in both tissue and water.
These methods can detect mercury and methylmercury in tissue and water
at very low levels--well below the levels of the previous criterion for
mercury in the water column and the current criterion of methylmercury
in fish tissue. This document also provides guidance for field sampling
plans, laboratory analysis protocols, and data interpretation that is
based on previously published EPA guidance on sampling strategies for
contaminant monitoring. This guidance also describes how states can
assess the attainment of water quality criteria and protection of
designated uses by comparing sampling data to water quality criteria.
This guidance also discusses approaches for the development of
TMDLs for waterbodies impaired by mercury. This includes approaches for
TMDLs for waterbodies where much of the mercury is from atmospheric
sources and suggestions regarding how such TMDLs can take into account
ongoing efforts to address sources of mercury, such as programs under
the Clean Air Act (CAA) and pollution prevention activities.
EPA's Technical Support Document for Water Quality-based Toxics
Control (TSD), EPA 505/2-90-001, explains how to implement criteria
expressed in terms of pollutant concentrations in water in NPDES
permits. States that decide to implement the methylmercury tissue
criterion as a water concentration for NPDES permits should continue to
use the TSD guidance. However, for states that decide to implement the
methylmercury tissue criterion directly, that is, without translating
it into a water column value, the TSD doesn't provide relevant
guidance. Today's draft guidance also includes a recommended approach
for directly incorporating the methylmercury tissue criterion in NPDES
permits.
F. Are There Particular Issues on Which EPA is Requesting Comment?
EPA requests comments only on the draft methylmercury criterion
implementation guidance. EPA is not requesting comments on the 2001
methylmercury criterion itself. Although EPA solicits comment on the
entire draft guidance, it is particularly interested in the following
topics:
1. Implementation Approach for NPDES Permits Where the Criterion Is
Implemented as a Fish Tissue Value
Today's guidance presents a recommended approach for directly
incorporating the methylmercury tissue criterion in NPDES permits. This
approach does not rely upon a state developing a bioaccumulation factor
to convert the methylmercury tissue criterion into a water
concentration equivalent. The approach recommends that facilities that
use, accept or receive mercury into their wastewaters develop mercury
minimization plans. For discharges that are small contributors of
mercury to a watershed or do not use mercury in their processes, the
approach recommends that current permit effluent levels remain
constant. EPA expects that most facilities will fall into this category
due to significant loadings from other sources (e.g., air deposition,
abandoned mines). For discharges that are significant contributors of
mercury to a watershed and use mercury in their processes, the approach
recommends that permit effluent limits ensure the attainment of water
quality standards. EPA expects that few dischargers should fall into
this category. For new or increased discharges, the approach recommends
that permit effluent limits hold watershed loadings constant using
antidegradation principles.
EPA solicits comment on the recommendations for directly
incorporating the methylmercury tissue criterion in NPDES permits. The
draft guidance recommends that a permitting authority could reasonably
conclude that reasonable potential exists if two conditions are present
(1) The NPDES permitted discharger has mercury in its effluent at a
quantifiable level and (2) fish tissue from the waterbody into which
the discharger discharges exceeds the fish tissue water quality
criterion. EPA specifically solicits comment on alternate methods,
based on using other information, for determining that there is
reasonable potential to exceed the water quality standard where fish
tissue data show that the methylmercury tissue criterion in a water
quality standard is achieved.
2. Applying Water Quality Variances on a Watershed or State-Wide Basis
Traditionally, states establish water quality variances that are
specific to a pollutant and a facility. EPA recognizes that, for
mercury, there are situations where a number of NPDES dischargers are
located in the same area or watershed and the justification supporting
granting a variance applies to all of the dischargers. Two states, Ohio
and Michigan, have already developed variances that apply to multiple
discharges for mercury. Today's guidance encourages states and
authorized tribes to consider establishing a multiple-discharger
variance for a group of dischargers collectively.
EPA solicits comment on whether it should discuss multi-discharge,
watershed, or state-wide variances in the final guidance.
G. References Cited
NRC (National Research Council). 2000. Toxicological effects of
methylmercury. Committee on the Toxicological Effects of
Methylmercury. National Academy Press. Washington, DC.
USEPA (U.S. Environmental Protection Agency). 1991. Technical
Support Document for Water Quality-based Toxics Control. EPA 505/2-
90-001. U.S. Environmental Protection Agency, Office of Water
Enforcement and Permits and Office of Water Regulations and
Standards.
USEPA (U.S. Environmental Protection Agency). 2001a. Water quality
criteria: Notice of Availability of water quality criterion for the
protection of human health: Methylmercury. U.S. Environmental
Protection Agency, Office of Water, Washington, DC. Fed. Regist.,
66:1344.
USEPA (U.S. Environmental Protection Agency). 2001b. Water quality
criterion for the protection of human health: Methylmercury. EPA-
823-R-01-001. U.S. Environmental Protection Agency, Office of Water,
Washington, DC.
USEPA (U.S. Environmental Protection Agency). 2002. Integrated Risk
Information System (IRIS). Methylmercury. U.S. Environmental
Protection Agency, Office
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of Research and Development, National Center for Environmental
Assessment.
USEPA (U.S. Environmental Protection Agency). 2005. Regulatory
Impact Analysis of the Clean Air Mercury Rule. Final Report. EPA-
452/R-05-003. U.S. Environmental Protection Agency, Office of Air
Quality Planning and Standards, Air Quality Strategies and Standards
Division, Research Triangle Park, NC.
Dated: August 3, 2006.
Benjamin H. Grumbles,
Assistant Administrator for Water.
[FR Doc. 06-6803 Filed 8-8-06; 8:45 am]
BILLING CODE 6560-50-P