[Federal Register Volume 62, Number 98 (Wednesday, May 21, 1997)]
[Proposed Rules]
[Pages 27707-27710]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 97-13325]
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ENVIRONMENTAL PROTECTION AGENCY
40 CFR Part 131
[FRL-5827-8]
Withdrawal From Federal Regulations of the Applicability to
Alaska of Arsenic Human Health Criteria
AGENCY: Environmental Protection Agency.
ACTION: Proposed rule and request for comments.
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SUMMARY: In 1992, EPA promulgated federal regulations establishing
water quality criteria for toxic pollutants for several states,
including Alaska (40 CFR 131.36). In this action, EPA is proposing to
withdraw the applicability to Alaska of the federal human health
criteria for arsenic. EPA is providing an
[[Page 27708]]
opportunity for public comment on withdrawal of the federal criteria
because the state's arsenic criteria differ from the federal criteria.
DATES: EPA will accept public comments on its proposed withdrawal of
the human health criteria for arsenic applicable to Alaska until July
7, 1997. Comments postmarked after this date may not be considered.
ADDRESSES: An original plus 2 copies, and if possible an electronic
version of comments either in WordPerfect or ASCII format, should be
addressed to Sally Brough, U.S. EPA Region 10, Office of Water, 1200
Sixth Avenue, Seattle, Washington, 98101.
The official administrative record for the consideration of this
proposal for arsenic is available for public inspection at EPA Region
10, Office of Water, 1200 Sixth Avenue, Seattle, Washington, 98101,
between 8:00 a.m. and 4:30 p.m. Copies of the record are also available
for public inspection at EPA's Alaska Operations Offices: 222 West 7th
Avenue, Anchorage, AK and 410 Willoughby Avenue, Janeau, AK.
FOR FURTHER INFORMATION CONTACT: Fred Leutner at EPA Headquarters,
Office of Water (4305), 401 M Street, SW, Washington, DC, 20460
(telephone: 202-260-1542), or Sally Brough in EPA's Region 10
(telephone: 206-553-1295).
SUPPLEMENTARY INFORMATION:
Potentially Affected Entities
Citizens concerned with water quality in Alaska, and with
pollution from arsenic in particular, may be interested in this
proposed rulemaking. Since criteria are used in determining NPDES
permit limits, entities discharging arsenic to waters of the United
States in Alaska could be affected by this proposed rulemaking.
Potentially affected entities include:
------------------------------------------------------------------------
Examples of affected
Category entities
------------------------------------------------------------------------
Industry.................................. Industries discharging
arsenic to surface waters
in Alaska.
Municipalities............................ Publicly-owned treatment
works discharging arsenic
to surface waters in
Alaska.
------------------------------------------------------------------------
This table is not intended to be exhaustive, but rather provides a
guide for readers regarding entities likely to be affected by this
action. This table lists the types of entities that EPA is now aware
could potentially be affected by this action. Other types of entities
not listed in the table could also be affected. To determine whether
your facility could be affected by this action, you should carefully
examine the applicability criteria in Sec. 131.36 of title 40 of the
Code of Federal Regulations. If you have any questions regarding the
applicability of this action to a particular entity, consult the person
listed in the preceding FOR FURTHER INFORMATION CONTACT section.
Background
On December 22, 1992, the Environmental Protection Agency (EPA or
Agency) promulgated a rule to establish federal water quality criteria
for priority toxic pollutants applicable in 14 states. That rule, which
is commonly called the National Toxics Rule (NTR), is codified at 40
CFR 131.36. The specific requirements for Alaska are codified at
Sec. 131.36(d)(12) and among other criteria, include water quality
criteria for the protection of human health from arsenic. EPA
promulgated a human health criterion for Alaska of 0.18 g/L to
protect waters designated for water consumption (i.e., sources of
drinking water) plus the consumption of aquatic life which includes
fish and shellfish such as shrimp, clams, oysters and mussels. This
criterion is located in column D1 in the criteria matrix at section
131.36(b)(1). EPA also promulgated a criterion of 1.4 g/L for
waters designated for the human consumption of aquatic life without
considering water consumption. This criterion is located in column D2
in the criteria matrix. These concentrations are designed to not exceed
an excess lifetime cancer risk of 1 in 100,000 (or 10-5) and
reflects Alaska's preference in recent rule adoptions and in
correspondence with EPA's Region 10. See 57 FR 60848, 60867.
EPA's criteria for human health protection from arsenic toxicity
used in the NTR were based on carcinogenic effects. Alaska had adopted
by reference EPA's published Clean Water Act (CWA) section 304(a)
criteria for human health into the state's water quality standards.
However, EPA's criteria guidance for carcinogens was presented at 3
different cancer risk levels, and the state had never officially
adopted a specific cancer risk level. Accordingly, since Alaska did not
have human health criteria for arsenic in place, EPA promulgated such
criteria for the state in the NTR.
Subsequent to the promulgation of the NTR, a number of issues and
uncertainties arose concerning the health effects of arsenic. EPA
determined that these issues and uncertainties were sufficiently
significant to necessitate a careful evaluation of the risks of arsenic
exposure. Accordingly EPA has undertaken a number of activities aimed
at reassessing the risks to human health from arsenic. [See Basis and
Purpose section below.]
In light of EPA's review of the health effects of arsenic, the
State of Alaska has proposed that the Safe Drinking Water Act (SDWA)
maximum contaminant level (MCL) for arsenic of 50 g/L
currently in the state's water quality standards be used as meeting the
requirements of the Clean Water Act in lieu of the current human health
criteria in the NTR. As adopted by Alaska, the MCL for arsenic applies
to all fresh waters that have the public water supply designated use.
(According to the state, this includes all but 20 fresh-water
segments.) For the reasons discussed subsequently, EPA finds that the
MCL for arsenic in freshwaters designated for public water supply, in
conjunction with Alaska's aquatic life criteria for arsenic, meets the
requirements of the CWA, and accordingly proposes to withdraw the
applicability to Alaska of the human health criteria for arsenic
promulgated in the NTR.
If EPA removes the applicability of the NTR arsenic human health
criteria to Alaska, the state has in place a chronic marine aquatic
life criterion of 36 g/L, a chronic freshwater aquatic life
criterion of 190 g/L, and the freshwater criterion of the MCL
of 50 g/L for waters designated for public water supply
discussed above. The aquatic life criteria are in place for all of the
state's marine and estuarine waters, and in those few cases where the
MCL is not applicable in freshwaters.
Basis and Purpose
There are a number of ongoing national activities that may affect
and/or necessitate a future change in the arsenic criteria for both
ambient and drinking water in Alaska. The National Academy of Sciences
(NAS) has initiated a study of the health risks posed by arsenic in
water. Results of the study are expected in the Spring of 1998.
Moreover, EPA is in the process of re-evaluating the risk assessments
for arsenic as part of a pilot program for reconfiguring the Integrated
Risk Information System (IRIS). EPA originally planned this re-
evaluation to cover aspects of both cancer and non-cancer risks and to
include examination of data not previously reviewed. With the
initiation of the NAS study, EPA redirected the focus of the IRIS re-
evaluation to the application of the proposed revisions to EPA's
Guidelines for Cancer Risk Assessment. The IRIS re-evaluation of
arsenic is expected in
[[Page 27709]]
1997. EPA encourages the state to review its water quality criteria for
arsenic as this new information becomes available.
EPA has recognized the use of appropriate MCLs in establishing
water quality standards under the CWA. Agency guidance notes the
differences between the statutory factors for developing SDWA MCLs and
CWA section 304(a) criteria, but provides that where human consumption
of drinking water is the principal exposure to a toxic chemical, then
an existing MCL may be an appropriate concentration limit. See guidance
noticed in 54 FR 346, January 5, 1989. Similarly, the CWA section
304(a) human health guidelines are consistent with this position. See
45 FR 79318, November 28, 1980.
To determine whether the MCL could appropriately be used in lieu of
the NTR's human health criteria for arsenic, EPA has prepared an
exposure analysis to estimate the significance of human consumption of
fish and shellfish containing the amounts of inorganic arsenic
indicated as present in representative samples of fish and shellfish,
in conjunction with the consumption of water containing concentrations
of arsenic currently existing in the Nation's waters. See EPA's
``Arsenic and Fish Consumption Concerns'' in the administrative record
for this rulemaking. This analysis first recognizes that the most
important toxic form of arsenic is inorganic arsenic. Inorganic arsenic
is the principal form in surface waters and almost the exclusive form
in ground waters. However, the arsenic in fish and most shellfish is
largely present as organic arsenic (mostly arsenobetaine). Available
information indicates that arsenobetaine passes through these organisms
with minimal retention in the fish and shellfish tissues.
In the NTR, EPA based the promulgated criteria on the human health
criteria methodology contained in the 1980 human health guidelines. To
estimate the ambient water concentration of a pollutant that does not
represent a significant risk to the public (i.e., the criteria levels),
the methodology makes certain assumptions about human exposure to
pollutants. The methodology assumes that for most people, drinking
water intake is 2 liters per day, and that fish consumption is 6.5
grams per day (a little less than one-half pound per month). The
methodology incorporates a bioconcentration factor (BCF) to account for
a pollutant's concentration in fish and shellfish tissue versus its
concentration in the water. The methodology also assumes that all of
the water and fish consumed is contaminated at the criteria levels (the
``safe'' levels).
Using these same exposure factors from the methodology, EPA has
assessed the effect of using the arsenic MCL. Assuming that the
concentration of arsenic in water is at the MCL of 50 g/L,
most people would be exposed to 100 g of arsenic from their
drinking water intake (i.e., 2 L/day x 50 g/L = 100
g/day), and 0.6 g/day of inorganic arsenic from
consuming 6.5 grams of fish and shellfish collected from water at the
arsenic MCL concentration and assuming the BCF used in the NTR. (See
derivation in EPA's ``Arsenic and Fish Consumption Concerns'' in the
record.) The total estimated exposure would be 100.6 g/day
which could consist entirely of inorganic arsenic. EPA considers the
small increment of exposure from fish consumption to be insignificant.
EPA therefore concludes that when applied to fresh waters in Alaska,
use of 50 g/L generally provides a level of protection
equivalent to that provided by the MCL. A full characterization of
other exposure scenarios is contained in EPA's exposure analysis
described above. This analysis is in the administrative record for this
proposal and is currently undergoing external peer review. The results
of the peer review will be considered before final action is taken on
this rule.
For regions in Alaska where high levels of arsenic in the potable
water are accompanied by high levels of fish and shellfish consumption,
the State of Alaska should develop site-specific criteria for the
surface waters involved considering the arsenic content of the drinking
water and fish consumed. In developing site-specific criteria the state
should characterize the size and location of the population of concern
and determine their fish/shellfish and water intake rates. The fish and
shellfish consumption should consider the species and dietary intake on
a per species basis. Actual total arsenic and inorganic arsenic values
for the species consumed and actual concentrations in drinking water
should be used in the exposure calculations whenever possible.
The Agency solicits comment on whether there are any locations in
Alaska where the arsenic criteria in the NTR should not be removed. For
such locations, EPA solicits data documenting such existing conditions
which indicate that fish consumers may be at an unacceptable risk of
arsenic toxicity, and whether some other site-specific arsenic human
health criteria may be appropriate. EPA solicits any information such
as that described above concerning possible site-specific criteria to
be developed by the State of Alaska.
Regulatory Procedural Information
This proposed withdrawal of human health criteria for arsenic in
Alaska is deregulatory in nature and would impose no additional
regulatory requirements or costs. Therefore, it has been determined
that this proposed action is not a ``significant regulatory action''
under the terms of Executive Order 12866 and is therefore not subject
to OMB review.
Based on the fact that this action is deregulatory in nature and
would impose no regulatory requirements or costs, pursuant to section
605(b) of the Regulatory Flexibility Act, the Administrator certifies
that this action will not have a significant economic impact on a
substantial number of small entities. EPA has determined that this
action does not contain a Federal mandate that may result in
expenditures of $100 million or more for state, local and tribal
governments, in the aggregate, or to the private sector in any one
year. EPA has also determined that this action contains no regulatory
requirements that might significantly or uniquely affect small
governments. Thus, today's action is not subject to the requirements of
sections 202, 203 and 205 of the UMRA.
This proposed rule does not impose any requirement subject to the
Paperwork Reduction Act.
List of Subjects in 40 CFR Part 131
Environmental protection, Water pollution control, Water quality
standards.
Dated: May 14, 1997.
Carol M. Browner,
Administrator.
For the reasons set out in the preamble, title 40, chapter I, part
131 of the Code of Federal Regulations is proposed to be amended as
follows:
PART 131--WATER QUALITY STANDARDS
1. The authority citation for part 131 continues to read as
follows:
Authority: 33 U.S.C. 1251 et seq.
Sec. 131.36 [Amended]
2. In Sec. 131.36(d)(12)(ii) the table is amended under the heading
``Applicable Criteria'', in the entry for ``Column D1'' and three
entries for
[[Page 27710]]
``Column D2'' by removing the number ``2'' from the list of numbers.
[FR Doc. 97-13325 Filed 5-20-97; 8:45 am]
BILLING CODE 6560-50-P
