[Federal Register: January 6, 2003 (Volume 68, Number 3)]
[Notices]
[Page 557-560]
From the Federal Register Online via GPO Access [wais.access.gpo.gov]
[DOCID:fr06ja03-58]
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ENVIRONMENTAL PROTECTION AGENCY
[OW-FRL-7435-7]
Nutrient Criteria Development; Notice of Ecoregional Nutrient
Criteria
AGENCY: Environmental Protection Agency (EPA).
ACTION: Notice of ecoregional nutrient criteria for lakes and
reservoirs, and rivers and streams.
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SUMMARY: Pursuant to section 304(a) of the Clean Water Act (CWA), the
Environmental Protection Agency (EPA) announces two actions: (1) The
finalization of nine section 304(a) ecoregional nutrient criteria
documents for lakes and reservoirs, and rivers and streams within
specific geographic regions (ecoregions) of the United States; and (2)
a request for significant scientific information on three new section
304(a) ecoregional nutrient criteria documents. These documents serve
as recommendations for States, Territories and authorized Tribes \1\ to
use as they develop nutrient criteria to protect designated uses and
adopt these criteria into water quality standards.
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\1\ Hereafter, this Federal Register Notice refers to these
entities as ``States and authorized Tribes.'' Throughout this
document, reference to States and authorized Tribes is intended to
include Territories.
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For Which New Documents Is EPA Requesting Significant Scientific
Information From the Public?
EPA invites the public to provide scientific views on three new
ecoregional nutrient criteria documents: Lakes and reservoirs in
ecoregions 1 and 10, and rivers and streams in ecoregion 13. EPA
requests significant scientific information pertaining to the
derivation of the draft criteria. EPA will accept significant
scientific information submitted to the Agency within 90 days of
publication of this notice in the Federal Register. Written significant
information to: Robert Cantilli, U.S. EPA, Health and Ecological
Criteria Division (4304), Office of Science and Technology, Ariel Rios
Building, 1200 Pennsylvania Ave., NW., Washington DC 20460. You may
also send comments by e-mail to: cantilli.robert@epa.gov.
What Are the Criteria Recommendations for These Three Ecoregions?
Aggregate Ecoregional (Agg. ER) Criteria Recommendations
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Parameter Agg. ER I Agg. ER X Agg. ER XIII
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TP [mu]g/L...................................................... 55.00 60.00 15.00
TN mg/L......................................................... *0.66 0.57 1.44
Chl a [mu]g/L................................................... 4.88 5.47
Secchi/Turbidity**.............................................. 2.55 0.77 1.49
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*Calculated--a value for TN was not available, so TN was calculated based on measurements of Total Kjeldahl
Nitrogen (TKN), and Nitrate + Nitrite (NO2+NO3).
**Secchi depth (m) is applicable to the values in Agg. ER's I and X. Turbidity (FTU) is applicable to Agg. ER
XIII.
Which Documents Are Final?
The nine documents being finalized today represent nutrient
criteria recommendations for lakes and reservoirs in ecoregions 3, 4,
5, and 14 and nutrient criteria recommendations for rivers and streams
in ecoregions 1, 4, 5, 8, and 10. EPA announced the availability of
these documents in the Federal Register on February 28, 2002. These
documents have undergone external peer review and have been reviewed by
the public.
What Are the Nutrient Criteria Recommendations for Those Ecoregions?
The following tables summarize criteria recommendations for lakes
and reservoirs and rivers and streams, respectively. Table 3 of each
document also provides values for each of the subecoregion (level III)
within each Aggregate ecoregion.
Aggregate Ecoregional (Agg. ER) Criteria Recommendations for Lakes and Reservoirs
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Parameter Agg. ER III Agg. ER IV Agg. ER V Agg. ER XIV
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TP [mu]g/L...................................... 17.00 20.00 33.00 8.00
TN mg/L......................................... 0.40 0.44 0.56 0.32
Chl a [mu]g/L................................... 3.40 2.00 (S) 2.30 (S) 2.90
Secchi (m)...................................... 2.70 2.00 1.30 4.50
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Chl a--Chlorophyll a measured by Flourometric method, unless specified. S is for Spectrophotometric.
[[Page 558]]
Aggregate Ecoregional (Agg. ER) Criteria Recommendations for Rivers and Streams
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Parameter Agg. ER 1 Agg. ER IV Agg. ER V Agg. ER VIII Agg. ER X
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TP [mu]g/L...................... 47.00 23.00 67.00 10.00 *128
TN mg/L......................... 0.31 0.56 0.88 0.38 0.76
Chl a [mu]g/L................... 1.80 2.40 3.00 0.63 2.10(S)
Turb (FTU)...................... 4.25 4.21 7.83 1.30 17.50
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* This number appears inordinately high and may either be a statistical anomaly or reflects a unique condition.
In any case, further regional investigation strongly encouraged to determine the sources, i.e., measurement
error, notational error, statistical anomaly, natural enriched conditions, or cultural impacts (impacts from
human activities).
Turb = Turbidity, FTU are nephelometric turbidity units, calibrated with formazin suspension.
What were the Main Submissions of Significant Scientific
Information Provided by the Public?
Many of the concerns raised by the public about EPA's approach for
developing nutrient criteria were raised earlier during the development
of EPA's Technical Guidance Manuals. At that time, questions were
raised about EPA's use of a statistical derivation of a reference
condition. EPA continues to believe these approaches are reasonable for
the purpose of making today's criteria recommendations. The Science
Advisory Board (SAB) endorsed the reference condition approach used by
EPA. The SAB stated in its review of ``Biological Criteria: Technical
Guidance for Streams and Small Rivers'' (EPA, 1993) that ``the
definition of reference condition using reference sites is appropriate
when used in conjunction with historical data, empirical models, and
expert opinion/consensus.'' EPA's Nutrient Criteria Program later
adopted the reference condition approach and continues to recommend it
in all of its nutrient criteria guidance manuals. Additionally, the
statistical derivation approach to developing nutrient criteria was
favorably reviewed by peer reviewers as well. Consequently, EPA did not
change its fundamental approach to nutrient criteria development or
change the documents significantly beyond responding to comments of
peer reviewers. Following is a summary of the most significant
scientific information submitted by the public. The issues are grouped
by topic, and then followed by EPA's response:
Percentile Approach
(1) The criteria are based on a statistical analysis of current
nutrient levels in the Nation's waters rather than on the latest
scientific knowledge and therefore are inconsistent with section 304(a)
of the Clean Water Act.
(2) The use of the 25th percentile of all data or the 75th
percentile of all reference data as criteria by States is undocumented,
not scientifically valid, and results in meaningless numerical criteria
values.
(3) Many data gaps exist in the nutrient database (for example a
lake with only one reading for a parameter in a given year). Some
screening techniques should have been done so that only those
waterbodies were included for which there are sufficient representative
data.
(4) The statistical approach used to develop the nutrient criteria
is statistically flawed because it ignores the relationship between
nutrient levels and in-stream/in-lake effects. As a result, there is no
way of knowing the environmental benefit or the level of protection of
designated uses gained by attaining the nutrient criteria levels set
forth in the documents. As a result, EPA's statistical derivation of
numerical nutrient criteria are meaningless to real world situations
and are not helpful in making watershed management decisions, TMDL
allocations, or in developing Water Quality Standards for nutrients at
the State level. Therefore, they should be withdrawn.
EPA Response: The mean, median and mode are measures of central
tendency commonly used in science to represent the distribution of a
population of observations. The frequency distribution approach is not
used to establish criteria; rather it is used to determine one of the
components of a criterion, the reference condition. This reference
condition is one element of a criterion which should be considered
along with historical background information, possible model
extrapolations of data, and consideration of possible downstream
impacts on those waters by a regional panel of experts (Regional
Technical Assistance Group--RTAG).
Further, the scientific community uses frequency distributions as a
common basic interpreter of data with the upper and lower quartiles as
an admittedly subjective, but traditional, approach to viewing the
extent of a distribution about a central tendency. It is not mandatory
or expected that the reference condition so derived be translated
directly into a criterion. The selection of an upper quartile (or lower
quartile with mixed water quality samples) is also consistent with the
EPA policy to set levels protective of the majority of waters and has
been peer reviewed both by EPA's SAB and external peer reviewers of our
water body type technical guidance.
Finally, EPA's technical guidance manuals provide examples of
alternate approaches to frequency distributions to assess reference
conditions and determine relationships among causal response variables.
Model Based Approach
The percentile-based nutrient criteria proposed by EPA are
acceptable only as a way to initiate a model-based, decision-theoretic
approach to standard setting (as described in submission) to be
undertaken by the effected States and Tribes with the assistance of
EPA.
EPA Response: The presumption underlying EPA's use of a reference
condition approach is that reference conditions reflect conditions
conducive to the protection of most aquatic life in the given water
body type and geographic region. The upper quartile of the reference
data distribution is an accommodation to variability of the reference
condition, and the lower quartile of a mixed sample is an effort to
approach this reference condition when insufficient a priori sites
exist. Therefore, the percentiles serve as recommended starting points
to be further refined by in the absence of refinements that may be
employed by the States, authorized Tribes and RTAGs.
Need for Site Specific Criteria
(1) Establishing a single nutrient criterion for all waters of a
geographically diverse region based on inadequate data is not an
appropriate approach. Numeric criteria should be developed at a site-
specific level.
(2) Regarding the chlorophyll standard: annual cycle of circadian
photo-periods vary significantly from southern Georgia to southern
Maine. Hours of daylight affect the growth of the chlorophyll in a
water body not only in photons activating chlorophyll but in
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water temperature. It is difficult to understand how a single standard
for chlorophyll or Secchi depth could be set over this geographic
distance.
(3) The recommended criteria are lower than concentrations that may
be needed to support fisheries and may result in a reduction of fish
biomass.
EPA Response: EPA is using an ecoregion approach as an initial
attempt to assess nutrient conditions in a broad geographic context.
The Agency encourages RTAGs, including member States and authorized
Tribes, to refine and further subdivide the initial ecoregions. If time
and resources permit, States and authorized Tribes should also consider
adopting nutrient criteria that are tailored to specific sites. EPA
believes that recommending nutrient criteria on an ecoregion basis,
with the use of ecoregional reference conditions, is a reasonable
alternative to recommending a single nation-wide criterion that may
fail to account for regional variability or to recommending criteria on
an individual water body basis, which would be very resource-intensive.
The EPA SAB has endorsed this region and water body-type specificity
for biological criteria, and nutrient criteria share a similar
ecological orientation.
One of the concerns expressed to EPA was that if the recommended
nutrient criteria were met, there would not be sufficient nutrients to
support fisheries. Generally, however, cultural eutrophication has been
identified by States' section 303 (d) reports as one of the top
national water quality problems. Where enrichment is documented as
beneficial by regional specialists, EPA recommends that nutrient
criteria be developed to promote the removal of that amount of ambient
total nitrogen and phosphorus in excess of optimal fish production as
determined by consultation of the RTAG with State and Federal fisheries
biologists and water resource managers.
Total Nitrogen Criteria
Total Nitrogen criteria are not necessary and should not be
required unless EPA can show site-specific reasoning for applying
nitrogen criteria to all water bodies.
EPA Response: As a threshold matter, it should be noted that EPA's
choice of parameters and criteria values are recommendations. The
documents announced today impose no requirements. States and authorized
Tribes have considerable flexibility in adopting nutrient criteria,
provided that the criteria meet the requirements of the CWA and EPA's
regulations (that is, they are based on sound scientific rationale and
contain sufficient parameters to protect the designated uses).
With respect to EPA's recommendation that States and authorized
Tribes adopt nutrient criteria for nitrogen, EPA notes that while
phosphorus is often considered the limiting nutrient determining the
extent of vegetative growth in fresh waters, nitrogen is often
considered to be the limiting nutrient in the lower reaches of
estuaries and in coastal marine waters. However, there are cases where
phosphorus limits algal growth in estuaries and nitrogen performs a
similar role in some freshwater systems. While nitrogen itself will not
usually cause water quality impairments in the near-field in
phosphorus-limited systems, if phosphorus supplies are reduced to
attenuate symptoms of eutrophication within freshwater segments of a
given river system, corresponding reductions in freshwater algal blooms
will allow the highly soluble dissolved forms of nitrogen to be
transported downstream. This downstream nitrogen transportation to
estuaries or costal waters may support larger algal blooms resulting in
water quality impairments. The practice of setting criteria for only
nitrogen or phosphorus in a given region could displace the
responsibility for nutrient abatement from the area of the source to a
downstream jurisdiction. This places an undue burden on the recipient
of this imported material and increases the abatement costs because
source control is lost as a management option. EPA suggests, therefore,
that where downstream effects take place, States and Tribes describe
technologies or best management practices in their plans to begin
nitrogen control.
Grouping of Reservoirs and Lakes
The final document should clarify whether Reservoir means impounded
stream or river. If impoundments were sampled with natural lakes, the
75th percentile number may be too high as a standard for historic
conditions in natural lakes.
EPA Response: EPA agrees that, if possible, reservoirs should not
be grouped with lakes and recommends in the Technical Guidance Manual
that, wherever feasible, criteria for reservoirs and lakes should be
developed separately. Using the National Nutrient Database, one can
separate data by lake or reservoir and determine reference conditions
for each.
How Can I Get Copies of These Documents?
You can get copies of the set of three new criteria documents or
any nutrient criteria document from the U.S. National Service Center
for Environmental Publications (NSCEP), 11029 Kenwood Road, Cincinnati,
OH 45242; (513) 489-8190 or toll free (800) 490-9198. The documents are
also available electronically at http://www.epa.gov/waterscience/standards/nutrient.html.
The waterbody-specific technical guidance
manuals are also available from EPA's nutrient Web site. EPA's Office
of Water, Office of Science and Technology prepared this document.
Mention of trade names or commercial products does not constitute
endorsement or recommendation for use.
Can the Public Continue To Provide Input After the Documents Are
Finalized?
EPA encourages the public to provide additional scientific
information that could help States and or authorized Tribes refine
these recommended nutrient water quality criteria. EPA identified
specific sections within each document where the public could greatly
assist States and authorized Tribes in the task of augmenting the
database for deriving ecoregional nutrient water quality criteria. For
example, the public can provide information about the historical
conditions and trends of the water resources within an ecoregion
related to eutrophication resulting from human activities. EPA will
forward all comments received on a particular ecoregional criterion or
set of criteria to the appropriate State or authorized Tribe to help
foster water quality criteria refinement.
SUPPLEMENTARY INFORMATION:
What Are Water Quality Criteria?
Section 304(a) of the Clean Water Act (CWA) requires the EPA to
develop and publish and, from time to time, revise criteria for water
quality accurately reflecting the latest scientific knowledge. Water
quality criteria recommendations developed under section 304(a) are
based solely on data and scientific judgments. They do not consider
economic impacts or the technological feasibility of meeting the
criteria in ambient water.
What Is the Purpose of These Documents?
These documents give State and Tribal decision makers and others
information to support the development
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of numeric nutrient criteria for lakes and reservoirs and rivers and
streams within several different nutrient ecoregions. An ecoregion is a
geographic area with assumed relative homogeneity of ecological
characteristics. EPA's section 304(a) criteria recommendations for
phosphorous, total nitrogen, chlorophyll a and some form of water
clarity, i.e. Secchi depth or turbidity represent reference conditions
of surface waters that are minimally affected by human activities and
provide for the protection and propagation of aquatic life and
recreation.
These recommendations do not substitute for the CWA or EPA's
regulations; nor are the documents themselves regulations. Thus, they
cannot impose legally binding requirements on EPA, States, Indian
tribes or the regulated community. Indeed, there may be other
approaches that would be appropriate in particular situations or
circumstances. When EPA reviews a new or revised nutrient water quality
criterion submitted by a State or authorized Tribe under CWA section
303(c), EPA will decide to approve or disapprove that submission on a
case-by-case basis and will be guided by the applicable requirements of
the Clean Water Act and implementing regulations, taking into account
comments and information presented at that time by interested persons
regarding the appropriateness of applying these recommendations to the
particular situation.
Why Does EPA Develop Ecoregional Nutrient Criteria?
States and authorized Tribes consistently identify excessive levels
of nutrients as a major reason why as much as half of the surface
waters surveyed in this country do not meet water quality objectives,
such as full support of aquatic life. In 2000, EPA published nutrient
criteria technical guidance manuals for lakes and reservoirs and for
rivers and streams. In 2001, EPA published a draft guidance manual for
estuarine and coastal marine waters. These manuals provide techniques
for assessing nutrient conditions as well as methods for developing
nutrient criteria for specific water body types. These and related
documents are also available from EPA's nutrient Web site: http://www.epa.gov/waterscience/standards/nutrient.html.
EPA is developing a
guidance manual for wetlands.
What Is the Total Set of Ecoregional Nutrient Criteria That EPA Has
Published?
On January 9, 2001, EPA announced the availability of ecoregional
nutrient criteria documents for lakes and reservoirs in eight
ecoregions, for rivers and streams in eight ecoregions (several of
which overlap with the eight ecoregions for lakes and reservoirs), and
for wetlands in one ecoregion. Those ecoregions were chosen based on
the availability of nutrient data within each ecoregion. On February
28, 2002, EPA announced the availability of nine ecoregional nutrient
criteria documents for lakes and reservoirs, and rivers and streams.
Today, EPA announces the availability of three additional ecoregional
nutrient criteria documents for lakes and reservoirs, and rivers and
streams. This brings the total number of ecoregional nutrient criteria
documents to 29 and results in nutrient criteria covering almost 100%
of the freshwater waterbodies of the U.S. (excluding wetlands).
EPA also provided guidance on development and adoption of nutrient
criteria into water quality standards. More recently, on November 14,
2001, Geoffrey H. Grubbs, Director of the Office of Science and
Technology, in EPA's Office of Water provided this guidance to EPA, and
State and Interstate Water Program Directors. This memorandum can be
viewed electronically at: http://www.epa.gov/waterscience/standards/nutrient.html
.
Dated: December 20, 2002.
Geoffrey H. Grubbs,
Director, Office of Science and Technology.
[FR Doc. 03-176 Filed 1-3-03; 8:45 am]
BILLING CODE 6560-50-U