S-EPA
United States Office of Water EPA-823-F-00-OOI
Environmental Protection 4305 May 2001
Agency
FACT SHEET
Water Quality Standards; Withdrawal of Nutrient
Standards for the State of Arizona
Summary
In 1976, EPA promulgated Federal criteria for nutrients in Arizona. The Federal
criteria included numeric ambient water quality criteria for nutrients for eleven river segments
and narrative water quality criteria for nutrients applicable to all surface waters in Arizona.
Since then, Arizona adopted its own numeric and narrative water quality criteria for nutrients,
which EPA approved. EPA also approved the implementation procedures for its narrative
nutrient water quality criteria that Arizona established. Because the nutrient criteria and
implementation procedures adopted by the State are scientifically defensible and consistent with
the Clean Water Act, EPA is proposing to withdraw the Federal criteria for nutrients applicable
in Arizona.
EPA is providing an opportunity for public comment on the withdrawal of the Federal
nutrient criteria. The Agency wants to know if the public thinks it is appropriate for it to remove
the Federal standards, which would leave in place the State's approved narrative criteria and
implementation procedures as the basis for which designated uses would be protected.
Background
In 1976, EPA determined that Arizona's revisions to its water quality standards did not
meet the requirements of the Clean Water Act (C WA). EPA promulgated Federal numeric
nutrient criteria for total nitrates and total phosphates applicable to eleven river segments in
Arizona. The Agency also promulgated narrative water quality criteria for nutrients applicable to
all surface waters in Arizona. Effective June 22,1976, these water quality criteria, codified at 40
CFR 131.31 (a), became the applicable water quality criteria for nutrients in Arizona for all
purposes and programs under the CWA.
Since EPA promulgated nutrient criteria for Arizona, the Arizona Department of
Environmental Quality (ADEQ), in a series of actions, adopted numeric nutrient criteria for total
nitrogen and total phosphorous applicable to specific water bodies in Arizona. Arizona also
adopted narrative nutrient criteria and implementation procedures applicable to all surface waters
of the State. EPA has determined that the numeric and narrative nutrient water quality criteria
adopted by the State from 1976 to 1996, along with the implementation procedures for the
narrative nutrient criteria, are fully protective of the designated uses of Arizona's waters and, as
such, are consistent with the CWA and implementing Federal regulations. EPA has, therefore,
determined that the 1976 Federal criteria for nutrients for Arizona waters are redundant and no
longer necessary.
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Today's Action
EPA's proposed rule, once finalized, will remove federally promulgated nutrient water
quality criteria for the State of Arizona. Arizona's numeric and narrative nutrient criteria, along
with the State's implementation procedures, will then become the only applicable water quality
standards for Arizona.
Additional Information
For additional information about this rule, contact either of the following:
Gary Sheth Jennifer Wigal
EPA Region 9 EPA Headquarters
Water Division Office of Water (.4305)
75 Hawthorne Street 1200 Pennsylvania Ave. NW
San Francisco, CA 94105 Washington, D.C. 20460
(415)744-2008 (202)260-5177
sheth.gary@epa.gov wigal.jennifer@epa.gov
You may view the Federal Register notice that describes this proposed rulemaking on the
Internet at http//www.epa.gov/waterscience/standards. The notice tells you how to get more
information, review the complete administrative record, and provide public comment for this
proposed rulemaking.
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