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[Federal Register Volume 69, Number 242 (Friday, December 17, 2004)]
[Notices]
[Pages 75541-75546]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 04-27665]

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ENVIRONMENTAL PROTECTION AGENCY

[OW-FRL-7849-4]

Notice of Draft Aquatic Life Criteria for Selenium and Request 
for Scientific Information, Data, and Views

AGENCY: Environmental Protection Agency (EPA).

ACTION: Notice of Availability of Draft Aquatic Life Criteria Document 
for Selenium, and Request for Scientific Information, Data, and Views 
Pertaining to the Criteria.

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SUMMARY: The Environmental Protection Agency announces the availability 
of a

[[Page 75542]]

draft aquatic life criteria document for selenium and requests 
scientific information, data, and views. The document contains draft 
water quality criteria recommendations for the protection of freshwater 
and saltwater aquatic life. EPA is soliciting information, data, and 
views on issues of science pertaining to the information the Agency 
used to derive the draft criteria. When completed and published in 
final form, the revised criteria will replace EPA's current recommended 
aquatic life criteria for selenium. EPA's recommended water quality 
criteria provide technical information for states and authorized tribes 
in adopting water quality standards, but themselves have no binding 
legal effect.

DATES: Scientific views, data, and information should be submitted by 
April 18, 2005.

ADDRESSES: Scientific information, data, and views may be submitted 
electronically, by mail, or through hand-delivery/courier. Follow 
detailed instructions provided in section C of the SUPPLEMENTARY 
INFORMATION section.

FOR FURTHER INFORMATION CONTACT: Charles Delos, e-mail 
[email protected] or postal address, Mail Code 4304T, U.S. EPA, 
1200 Pennsylvania Avenue NW., Washington, DC 20460 at (202) 566-1097.

SUPPLEMENTARY INFORMATION:

A. Which Entities Might Be Interested?

    Entities potentially interested in today's notice are those that 
discharge or release selenium to surface waters, and federal, state, 
tribal, and local authorities that regulate selenium levels in surface 
water. Categories and entities interested in today's notice include but 
are not limited to:

------------------------------------------------------------------------
                                               Examples of interested
                 Category                             entities
------------------------------------------------------------------------
State/Local/Tribal Government.............  States, municipalities,
                                             tribes.
Industry..................................  Mining, coal-fired power
                                             generation.
Agriculture...............................  Irrigated agriculture.
------------------------------------------------------------------------

    This table is not intended to be exhaustive. Other types of 
entities not listed in the table may also be interested.

B. How Can I Get Copies of the Draft Document and Related Information?

    1. Docket. EPA has established an official public docket for this 
action under Docket ID No. OW-2004-0019. The official public docket is 
the collection of materials that are available for public viewing at 
the Water Docket in the EPA Docket Center, EPA West, Room B102, 1301 
Constitution Ave., NW., Washington, DC. The EPA Docket Center 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. Alternatively, copies of the draft may be 
obtained from EPA's Water Resource Center by phone at (202) 566-2426, 
or by e-mail to [email protected] or by conventional mail 
to: EPA Water Resource Center, 4101T, 1200 Pennsylvania Avenue NW., 
Washington, DC 20460.
    2. Electronic Access. Use http://www.epa.gov/waterscience/criteria/aqlife.html to obtain the draft document. Use http://www.epa.gov/fedrgstr/ to obtain this Federal Register document electronically.
    An electronic version of the public docket is available through 
EPA's electronic public docket and comment system, EPA Dockets. You may 
use EPA Dockets at http://www.epa.gov/edocket/ to access the index 
listing of the contents of the official public docket and to access 
those documents in the public docket that are available electronically. 
Although not all docket materials may be available electronically, you 
may still access any of the publicly available docket materials through 
the docket facility identified in section B.1. Once in the system, 
select ``search,'' then key in the appropriate docket identification 
number.
    Certain types of information will not be placed in the EPA Dockets. 
Information claimed as Confidential Business Information (CBI) and 
other information whose disclosure is restricted by statute, which is 
not included in the official public docket, will not be available for 
public viewing in EPA's electronic public docket. EPA's policy is that 
copyrighted material will not be placed in EPA's electronic public 
docket but will be available only in printed, paper form in the 
official public docket. To the extent feasible, publicly available 
docket materials will be made available in EPA's electronic public 
docket. When a document is selected from the index list in EPA Dockets, 
the system will identify whether the document is available for viewing 
in EPA's electronic public docket. Although not all docket materials 
may be available electronically, you may still access any of the 
publicly available docket materials through the docket facility 
identified in section B.1.
    It is important to note that EPA's policy is that data, 
information, and views, whether submitted electronically or in paper, 
will be made available for public viewing in EPA's electronic public 
docket as EPA receives them and without change, unless the data or 
information contains copyrighted material, CBI, or other information 
whose disclosure is restricted by statute. When EPA identifies 
copyrighted material, EPA will provide a reference to that material in 
the version of the document that is placed in EPA's electronic public 
docket. The entire printed document, including the copyrighted 
material, will be available in the public docket.
    Data, information, and views submitted on computer disks that are 
mailed or delivered to the docket will be transferred to EPA's 
electronic public docket. Data, information, and views that are mailed 
or delivered to the Docket will be scanned and placed in EPA's 
electronic public docket. Where practical, physical objects will be 
photographed, and the photograph will be placed in EPA's electronic 
public docket along with a brief description written by the docket 
staff.

C. How Do I Submit Scientific Information, Data, or Views?

    You may submit scientific information, data, or views 
electronically, by mail, or through hand delivery/courier. To ensure 
proper receipt by EPA, identify the appropriate docket identification 
number in the subject line on the first page.
    1. Electronically. EPA recommends that you include your name and 
mailing address, or e-mail address or other contact information, 
particularly if you submit data in tables or figures. Also include this 
contact information on the outside of any disk or CD ROM you submit, 
and in any cover letter accompanying the disk or CD ROM. This ensures 
that you can be identified as the submitter and allows EPA to contact 
you in case EPA has technical difficulties reading your submission or 
needs further information on the substance of your submission. EPA's 
policy is that EPA will not edit your submission, and any identifying 
or contact information provided in the body of the submission will be 
included in the official public docket, and made available in EPA's 
electronic public docket. If EPA cannot read your submission due to 
technical difficulties and cannot contact you for clarification, EPA 
may not be able to consider it.
    i. EPA Dockets. Your use of EPA's electronic public docket to 
submit data, information, and views to EPA electronically is EPA's 
preferred method for receiving submissions. Go directly to

[[Page 75543]]

EPA Dockets at http://www.epa.gov/edocket and follow the online 
instructions. Once in the system, select ``search,'' and then key in 
Docket ID No. OW-2004-0019. The system is an ``anonymous access'' 
system, which means EPA will not know your identity, e-mail address, or 
other contact information unless you provide it.
    ii. E-mail. Submissions may be sent by electronic mail (e-mail) to 
[email protected] attention Docket ID No. OW-2004-0019. In contrast to 
EPA's electronic public docket, EPA's e-mail system is not an 
``anonymous access'' system. If you send an e-mail directly to the 
Docket without going through EPA's electronic public docket, EPA's e-
mail system automatically captures your e-mail address. E-mail 
addresses that are automatically captured by EPA's e-mail system are 
included as part of the submission that is placed in the official 
public docket, and made available in EPA's electronic public docket.
    iii. Disk or CD ROM. You may send your submission on a disk or CD 
ROM to the mailing address identified in section B.1. These electronic 
submissions will be accepted in WordPerfect or ASCII file format. Avoid 
the use of special characters and any form of encryption.
    2. By Mail. Send an original and three copies of your submission 
to: Water Docket, Environmental Protection Agency, Mailcode: 4101T, 
1200 Pennsylvania Ave., NW., Washington, DC 20460, Attention Docket ID 
No. OW-2004-0019.
    3. By Hand Delivery or Courier. Deliver your submission to: EPA 
Docket Center (EPA/DC), EPA West, Room B102, 1301 Constitution Ave., 
NW., Washington, DC 20460, Attention Docket ID No. OW-2004-0019. Such 
deliveries are only accepted during the Docket's normal hours of 
operation as identified in section B.1.

D. What Are EPA Recommended Water Quality Criteria?

    An EPA recommended water quality criterion is a level of a 
pollutant or other measurable substance in water that, when met, will 
protect aquatic life and/or human health. Section 304(a) of the Clean 
Water Act (CWA) requires EPA to develop and publish and, from time to 
time, revise, recommended water quality criteria to accurately reflect 
the latest scientific knowledge. Water quality criteria developed under 
section 304(a) provide guidance to states and tribes in adopting water 
quality criteria into their water quality standards under section 
303(c). Once adopted by a state or tribe, the water quality standards 
then are a basis for developing regulatory controls on the discharge or 
release of pollutants and other alterations of water quality. EPA's 
section 304(a) criteria also provide a scientific basis for EPA to 
develop any necessary federal water quality regulations under section 
303(c) of the CWA.
    The draft criteria in today's notice are based on the factors 
specified in section 304(a) of the Clean Water Act, including the kind 
and extent of effects of the pollutant on human health and aquatic 
organisms. Under the Clean Water Act, the EPA can not consider the 
economic and technical feasibility of meeting the draft criteria in 
their development. Economic and technical feasibility factors are 
considered by states and tribes when they adopt water quality criteria 
into their water quality standards under section 303(c) of the Act and 
when states, tribes, and EPA consider variance requests for regulatory 
controls. Moreover, states and tribes may also consider alternative 
scientifically-defensible approaches to adopting criteria into their 
water quality standards that may be different from approaches presented 
by EPA in final water quality criteria published under section 304(a).

E. What Is Selenium and Why Are We Concerned About It?

    Selenium is a naturally-occurring element that is nutritionally 
essential. However, it has been toxic to aquatic life and terrestrial 
wildlife where concentrations were excessive. Under real-world field 
conditions, aquatic life is exposed to selenium primarily through the 
diet. When the input of a toxic substance to an organism is greater 
than the rate at which the substance is lost, the organism is said to 
bioaccumulate that substance. Although selenium bioaccumulates in 
aquatic organisms, it is not significantly biomagnified. That is, 
concentrations do not increase significantly in aquatic organisms at 
each successive level of the food chain. For aquatic life, the lowest 
toxic thresholds (the smallest levels at which toxic effects are 
noticeable) are generally associated with effects on larval offspring 
of the adult fish that were exposed to excessive selenium or with 
effects on juvenile fish.
    Being a natural element, selenium is everywhere in the environment. 
Concerns about too much selenium in water have most often been 
associated with irrigation return flows from soils that are naturally 
high in selenium, ash pond discharges from coal-fired power plants (due 
to the selenium content of coal), and certain mining activities (due to 
exposure of selenium-bearing soil or rock to weathering).

F. What Has EPA Done in the Past on the Aquatic Life Criteria for 
Selenium?

    EPA's currently-recommended aquatic life water quality criteria for 
selenium were published in 1987. EPA made minor adjustments in the 
criteria concentrations when it converted the selenium criteria from a 
total recoverable (dissolved plus particulate) measurement basis to a 
dissolved measurement basis in 1995 and 1999 as follows: (a) In 60 FR 
15366, March 23, 1995, only for the Great Lakes Initiative; (b) in 60 
FR 22228, May 4, 1995, only for the saltwater criteria; and (c) in 64 
FR 19781, April 22, 1999, optionally for freshwater nationwide.
    In 1996, EPA proposed but did not complete an additional change in 
the freshwater acute criterion for the Great Lakes system (61 FR 58444, 
November 14, 1996). In 2000, EPA revoked the existing acute criterion 
for the Great Lakes system (65 FR 35283, June 2, 2000) in response to a 
lawsuit challenging the use of a single acute criterion applicable to 
selenite and selenate, the two common chemical forms of selenium (see 
AISI v. EPA, 115 F. 3d 979 (D.C. Cir. 1997)).
    EPA's most recent compilation of criteria presents (a) the above-
mentioned 1996 GLI proposed freshwater acute criteria, (b) the 1987 
freshwater chronic criterion, and (c) the 1987 saltwater acute and 
chronic criteria as converted to dissolved in 1995. You can find the 
compilation at www.epa.gov/waterscience/standards/wqcriteria.html.
    In 1998 EPA held a peer consultation workshop to evaluate possible 
courses of action regarding the selenium aquatic life criterion and 
notified the public of our intent to review the selenium criteria. In 
1999, EPA announced its intention to revise its national aquatic life 
criterion for selenium and requested data (64 FR 58409, October 29, 
1999).
    In 2002, EPA prepared an early draft revision of its aquatic life 
criteria document and submitted it to peer review (Versar 2002, Lemly 
2004). EPA considered the comments and suggestions submitted by the 
peer reviewers (U.S. EPA 2004b) and made many technical and scientific 
changes in response (U.S. EPA 2004a). In the future, EPA will review 
any scientific information, data, and views submitted in response to 
today's notice. The Agency will also continue to work closely with the 
U.S. Fish and Wildlife Service and other key federal agencies to arrive 
at final water quality criteria

[[Page 75544]]

for selenium which are protective of aquatic life.
    Today's announcement of the draft aquatic life criteria document 
for selenium has no effect on EPA's human health criteria 
recommendation for selenium published in 2002 (see http://epa.gov/waterscience/standards/wqcriteria.html).

G. What Are the Draft Aquatic Life Criteria Values?

    The draft selenium criteria recommendations state that freshwater 
aquatic life should be protected under the following conditions:
    A. The concentration of selenium in whole-body fish tissue is not 
more than 7.91 [mu]g/g (micrograms per gram) dw (dry weight). This is 
the chronic exposure criterion. In addition, if whole-body fish tissue 
concentrations exceed 5.85 [mu]g/g dw during summer or fall, fish 
tissue should be monitored during the winter to determine whether the 
selenium concentration exceeds 7.91 [mu]g/g dw.
    B. The 24-hour average concentration of total recoverable 
(dissolved and particulate) selenium in water seldom (e.g., not more 
than once in three years) exceeds 258 [mu]g/L for selenite, and 
likewise seldom exceeds the numerical value given by 
exp(0.5812[ln(sulfate)]+3.357) for selenate. These are the acute 
exposure criteria. At an example sulfate concentration of 100 mg/L, the 
24-hour average selenate concentration should not exceed 417 [mu]g/L. 
Sulfate is a commonly measured water quality parameter that has been 
found to have a mitigating influence on the acute toxicity of the 
selenate form of selenium.
    Likewise, the draft selenium criteria recommendations state that 
saltwater aquatic life should be protected from acute effects of 
selenium if the 24-hour average concentration of selenite seldom 
exceeds 127 [mu]g/L. Because selenium might be as chronically toxic to 
saltwater fishes as it is to freshwater fishes, the fish community 
should be monitored if selenium exceeds 5.85 [mu]g/g dw in summer or 
fall or 7.91 [mu]g/g dw during any season in the whole-body tissue of 
saltwater fishes.

H. What Would the Draft Aquatic Life Criteria Recommendations Protect?

    The draft selenium criteria recommendations were derived from data 
on aquatic life and are intended to protect aquatic life. Specifically, 
the draft chronic exposure recommendation is designed to protect 
against mortality, reproductive interferences, and growth abnormalities 
in fish and other aquatic organisms due to long-term excessive exposure 
to selenium in the aquatic food chain. The draft acute exposure 
recommendations are designed to protect against lethality or 
immobilization of aquatic organisms due to brief elevated exposure to 
selenium in water.
    Although the draft recommendation took into account dietary 
exposure for aquatic life, no nationally-applicable scientific 
methodology yet exists to derive national water quality criteria to 
protect birds or terrestrial wildlife that consume fish, water, or 
aquatic plants and organisms that contain selenium. Therefore, this 
draft selenium recommendation is not designed to protect birds or 
terrestrial wildlife. (Similarly, EPA's existing 1987 water quality 
criteria for selenium were not designed to protect birds or wildlife.) 
However, EPA is working with the U.S. Fish and Wildlife Service and 
other interested federal agencies to develop selenium criteria 
protective of wildlife within the State of California. The California-
specific wildlife criteria effort is separate from the national-scale 
draft aquatic life criteria announced in today's notice. Its 
development is on a different time track; it involves analysis of 
toxicity data for aquatic-dependent wildlife (not aquatic life); and it 
is intended to apply only to California.

I. How Do the Draft Aquatic Life Criteria Recommendations Differ From 
Previous Criteria Recommendations?

    In contrast to the existing 1987 freshwater chronic criterion, 
which was expressed as a conventional water concentration, the draft 
freshwater chronic criterion sent to peer review in 2002 and the draft 
criterion announced in today's notice are each expressed as a whole-
body fish tissue concentration ([mu]g selenium per gram of fish tissue 
on a dry weight basis). At a given location or for a given water body, 
a fish tissue level of selenium can be used with a site-specific 
bioaccumulation factor to estimate the concentration of selenium in the 
water. A bioaccumulation factor is a measured or predicted ratio 
between the tissue concentration and the water concentration of a 
chemical, in this case, selenium.
    Early in the process of developing these draft criteria, EPA 
concluded, and the peer reviewers agreed that a fish-tissue approach is 
better than a conventional water concentration approach to protect 
aquatic life from the chronic adverse effects of selenium. Because fish 
and aquatic invertebrates are exposed to selenium primarily through 
their diet rather than directly through water, the fish-tissue 
concentration better reflects site-specific exposure and risk than does 
the water concentration. Therefore, using the fish-tissue approach 
allows users to consider site-specific factors in translating to a 
water concentration.
    However, consistent with the type of toxicity tests used for their 
derivation, the draft aquatic life criteria to protect against the 
acute effects of selenium in fresh water and salt water are expressed 
as traditional water concentrations (total recoverable selenium). 
Expanding the toxicity database with a substantial number of more 
recent acute toxicity tests yielded relatively little change in the 
freshwater selenite criterion, but yielded a substantial increase in 
the selenate criterion due to repeated retesting of an amphipod that 
formerly appeared to have an anomalously low LC50, and due to 
normalization of the acute data for sulfate concentration. 
Normalization of all acute test results for sulfate concentration 
reveals that some species formerly thought to be highly sensitive were 
actually tested at low sulfate. Including sulfate in the draft criteria 
formula assures their protection at low sulfate concentrations. 
Expansion of the database caused the saltwater selenite criterion to 
decrease because a scallop, formerly untested, was found to be highly 
sensitive. A saltwater chronic criterion is not presented in the draft 
announced today, because EPA lacks sufficient and appropriate data to 
derive one.

J. Are There Particular Issues on Which EPA is Requesting Scientific 
Information, Data, and Views?

    EPA is requesting information, data, and views on all facets of the 
science supporting the draft criteria recommendations for selenium, but 
it is particularly interested in the following topics:

1. The Appropriateness of Basing the Freshwater Chronic Criterion on a 
Tissue Concentration

    Because the same water concentration may yield different amounts of 
bioaccumulation and therefore different levels of risk at different 
sites, EPA developed this draft criterion as a fish tissue 
concentration to reduce the need for resetting the criterion on a site-
by-site basis. Where translation from the tissue benchmark to a water 
concentration is needed, a bioaccumulation factor (BAF), which may vary 
substantially from site to site, would need to be established.
    Participants in the 1998 Peer Consultation Workshop suggested that 
a tissue-based approach for a selenium aquatic life criterion would be 
feasible

[[Page 75545]]

(U.S. EPA 1998). The underlying concept is different from that used 
historically for developing aquatic life criteria that are applied to 
the water column, the surrounding environment shared by a range of 
aquatic species. Nevertheless, this tissue-based approach appears to be 
appropriate because, at concentrations not far above the draft 
criterion, selenium is toxic to the offspring (embryos, larvae, or 
juveniles) of sensitive species, but not to the adult fish that might 
be present and from which an environmental sample could be taken.
    EPA is requesting scientific information, data, and views on (a) 
the concept of protecting aquatic life by applying a criterion to 
whole-body fish tissue concentrations of selenium, (b) the 
appropriateness of applying a fish tissue-based water quality criterion 
uniformly across waterbodies to protect sensitive species, and (c) the 
possibility of applying the same criterion to invertebrate tissue where 
invertebrate samples are obtained with or in place of fish tissue 
samples.
    Because EPA has not yet made decisions on the form or values of its 
final water quality criteria for selenium, EPA has not yet developed 
implementation procedures. Therefore, EPA is also interested in 
scientific information, data, and views on (d) approaches for sampling 
tissues, and (e) available data for deriving localized BAF values for 
translating the tissue concentrations to water concentrations, where 
needed for pollution control decisions.

2. Studies of Freshwater Aquatic Life Effects and Chronic Effect 
Concentrations

    Based on studies involving exposure through a contaminated diet, 
the genus mean chronic EC20 (concentration effecting 20% of test 
organisms) for effects on larval or juvenile common sunfish (Lepomis) 
was found to be 9.5 [mu]g/g dry weight whole body concentration of 
selenium in the adult parental fish or in the juveniles (depending on 
the study). This genus mean value is based on four studies. No data 
indicated that other genera were more sensitive than Lepomis. Useful 
chronic toxicity data were available for a rotifer (a small 
invertebrate), chinook salmon, rainbow trout, cutthroat trout, fathead 
minnow, flannelmouth sucker, razorback sucker, stripped bass, and a 
mixture of sunfish.
    One of the above studies was by Lemly (1993), who investigated 
overwinter survival of juvenile bluegill in the laboratory. This study 
consisted of a control (only background selenium exposure) and one 
elevated selenium exposure level, both subjected either to (a) a 
temperature regime of 20 [deg]C for 180 days, or (b) a temperature 
regime changing from 20 [deg]C to 4 [deg]C over the course of 60 days, 
and remaining at 4 [deg]C for the remaining 120 days of the study. He 
observed substantially less survival when elevated selenium was 
combined with low temperature. The whole body concentration associated 
with mortality was 5.85 [mu]g/g at Day 60 just prior to a significant 
increase in mortality, and 7.91 [mu]g/g later in the study during and 
subsequent to the death of 40% of the organisms. For the same selenium 
exposure at 20 [deg]C, mortality was 6% and whole body concentrations 
were 5.74 [mu]g/g. Little mortality was observed at either temperature 
regime for unexposed organisms, but since there was only one selenium 
treatment, no concentration-response curve can be constructed.
    One possible implication of the Lemly (1993) study might be that 
effects on overwinter survival of juveniles occur at lower 
concentrations than do effects on reproduction or early life stages. In 
the Monticello macrocosm study, at 4 to 5[deg]C overwinter conditions, 
reproductive success and adult bluegill overwinter survival were 
unaffected at concentrations higher than those of the Lemly (1993) 
study (Hermanutz et al. 1996, corrected by Tao et al. 1999, and peer 
reviewed in Versar 2000).
    Based on the Lemly (1993) results, to protect sensitive fish 
species under winter conditions, EPA has set the draft criterion at 
7.91 [mu]g/g, the concentration measured during the period of reduced 
survival, with the provision that winter monitoring should be performed 
if summer or fall tissue levels exceed 5.85 [mu]g/g, the concentration 
occurring prior to the period of reduced survival. Three of five peer 
reviewers of the 2002 draft questioned whether the results from only 
one study should be used as the basis for lowering the nationally 
recommended criteria from 9.5 [mu]g/g to 7.91 [mu]g/g as EPA has done 
in this document. On the other hand, U.S. Fish and Wildlife Service 
(White 2002) has questioned whether 7.91 [mu]g/g is sufficiently 
protective, citing the high mortality observed at that tissue 
concentration during the study.
    EPA is requesting scientific information, data, and views on (a) 
the most appropriate interpretation and use of the Lemly (1993) 
results, and its applicability to a range of climatic regimes and 
fisheries types and (b) other data that may be relevant to the winter 
exposure issue. Because EPA expects it has seen all the available 
laboratory studies relevant to the issue, it is particularly interested 
in field observations (such as age structure or species occurrence) 
that may be relevant to the selenium winter exposure issue under 
various climatic conditions. EPA is also requesting scientific 
information, data, and views on (c) approaches for accounting for 
different climatic conditions.

3. Alternative Values for the Freshwater Chronic Criterion

    The current draft criteria document has set the aquatic life 
criterion for selenium at a whole body fish tissue concentration of 
7.91 [mu]g/g, with the provision that winter monitoring should be 
performed if summer or fall tissue levels exceed 5.85 [mu]g/g. EPA is 
requesting information and analyses relevant to alternative fish tissue 
benchmarks. EPA will only consider analyses that have a formal, fully 
transparent, and reproducible derivation from laboratory or field data, 
where all the supporting information quantifies a toxic effect metric 
and an exposure metric.
    EPA is also receptive to formally-derived benchmarks applicable to 
other aquatic media, such as water, sediment, or prey tissue. Again, 
the derivations should be transparent and fully reproducible from 
laboratory or field data.

4. Site-Specific Factors Affecting the Freshwater Chronic Criterion

    Expressing the chronic criterion as a tissue concentration rests on 
the assumption that there is reasonable geographic uniformity in the 
tissue threshold, while the BAF, and therefore the water concentration 
threshold, may vary considerably across sites. EPA believes that the 
route of exposure affects the tissue threshold. The same tissue 
concentration, if accumulated through water-only exposure, appears to 
be more toxic than if accumulated via diet. Fish provided with an 
uncontaminated diet and exposed to very high water concentrations of 
selenium (for example, 300 [mu]g/L in the Cleveland et al. (1993) 
study) may show effects when whole body concentrations exceed only 4 
[mu]g/g. When exposed through a contaminated diet but essentially 
uncontaminated water in the same study, effects were not observed until 
tissue concentrations exceeded around 13 [mu]g/g.
    Because EPA did not use studies involving uncontaminated diets 
coupled with high water exposures, the criterion assumes that the 
dominant environmental exposure route for the target species is 
dietary. Consistent with the views of the EPA peer consultation

[[Page 75546]]

workshop in 1998, EPA believes that this assumption corresponds to the 
real-world problems of selenium contamination.
    While recognizing that the BAF can vary from site to site, EPA is 
requesting scientific information, data, and views on the general 
approach of using a uniform tissue benchmark (expressed as total 
selenium concentration in whole body) without regard to site 
differences that might include:
     The species to be protected,
     The type of water body,
     The character of the food web, for example, autochthonous 
versus nonseleniferous allochthonous,
     The form and concentration of selenium in the water or 
diet,
     The form of selenium in the sampled tissue,
     The nature of the selenium release,
     Interactions with other trace elements,
     Acclimation or adaptation,
     Hormesis,
     Climatic conditions, and
     Any other relevant site factors.
    EPA is also requesting scientific information, data, and views 
relevant to the need for and appropriate basis for adjusting the tissue 
benchmark to account for site-specific factors.

5. Saltwater Chronic Criterion

    For chronic exposure, we found no data that were useful for 
deriving a saltwater aquatic life criterion. However, selenium might be 
as toxic in the tissues of saltwater organisms as it is in the tissues 
of freshwater organisms. Therefore, the draft contains the cautionary 
recommendation that the status of the saltwater fish community be 
monitored if selenium exceeds 5.85 [mu]g/g dw in summer or fall or 7.91 
dw during any season (same as the freshwater benchmarks) in the whole-
body tissue of saltwater fishes.
    EPA is requesting scientific information, data, or views on (a) 
toxicity thresholds applicable to protecting saltwater organisms 
exposed to selenium through the food chain, or (b) the appropriateness 
of extending to saltwater what is known about freshwater toxicity 
thresholds.

6. Acute Criteria Concentrations

    As discussed above, selenium toxicity problems have generally 
involved contamination of the food web. If the diet of the target 
species is not contaminated, very high water-column concentrations are 
needed to bring out effects, particularly when exposure is brief. As 
with bioaccumulative pollutants in general, acute toxicity (that is, 
toxicity from a brief sharp increase in the water concentration) is of 
less concern than chronic exposure through the food chain.
    Nevertheless, a large body of toxicity test data are available for 
brief water-only exposure. Therefore, EPA was able to derive acute 
criteria to protect aquatic life against the toxic effects of that type 
of exposure to selenium. For ambient freshwater, the draft selenite or 
Se (IV) acute criterion is 258 [mu]g/L, and the draft sulfate-dependent 
selenate or Se (VI) criterion ranges from 109 to 1590 [mu]g/L at 
sulfate concentrations from 10 to 1000 mg/L. For ambient saltwater the 
draft selenite acute criterion is 127 [mu]g/L.
    EPA is requesting scientific information, data, and views on the 
appropriateness of the draft values for the acute exposure criteria.

References

    Hermanutz, R.O., K.N. Allen, N.E. Detenbeck, and C.E. Stephan. 
1996. Exposure to bluegill (Lepomis macrochirus) to selenium in 
outdoor experimental streams. U.S. EPA Report. Mid-Continent Ecology 
Division, Duluth, MN.
    Lemly, A.D. 1993. Metabolic stress during winter increases the 
toxicity of selenium to fish. Aquat. Toxicol. (Amsterdam) 27(1-
2):133-158.
    Lemly, D. 2004. Letter to Denise Keehner. U.S. Department of 
Agriculture, Forest Service. June 22, 2004.
    Tao, J., P. Kellar, and W. Warren-Hicks. 1999. Statistical 
analysis of selenium toxicity data. Report submitted for U.S. EPA, 
Health and Ecological Criteria Division. The Cadmus Group, Inc., 
Durnham, NC.
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    Dated: December 9, 2004.
Geoffrey H. Grubbs,
Director, Office of Science and Technology.
[FR Doc. 04-27665 Filed 12-16-04; 8:45 am]
BILLING CODE 6560-50-P
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