REVIEW OF THE SELENIUM HEALTH CRITERIA DOCUMENT
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PB89-109029
Review of the Selenium
Health Criteria Document
(U.S.) Environmental Protection Agency
Washington, DC
19 jul 88
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' 30277-Iffl
REPORT DOCUMENTATION
PAGE
1. REPORT NO.
SAB-EHC-88-036
4. THI. end subtrti* Review of the Selenium Health Criteria Document
PB89-109029
5. Report Data
July 19, 1988
7. Author(»)
Metals Subcommittee
I. Performing Organization Rapt. No.
9. Performing Orgrnlntlon Nam* and Addretl
Environmental Protection Agency
Science Advisory Board
499 S. Capitol Street, SW
Washington, D.C. 20460 (A101F)
10. Prolect/Task/Work Unit No.
II. Contnct(C) or Qrant(O) No.
(C)
(Q)
12. Spontorlnf Organization Ntmt ind Address
Environmental Protection Agency
401 M STreet, SW
Washington, D.C. 20460
IS. Type of Report & Period Covered
Final Report
14.
IS. Supplementary Notet
16. Abstract (Limit: 200 word*)
Metals Subcommittee of the Science Advisory Board's
Environmental Health Committee has completed its review of the
Drinking Water Health Criteria Document for Selenium.dated December
1986. The review was conducted January _14- 15, 19%jT~a"€' the ~StT
James Hotel in Washington, D.C. C^The Subcommittee made" two
recommendations; that more informatio'n was needed in the document
on the studies on which the standard is based and that the Drinking
Water Equivalent Level (DWEL) should be 200 roicrograms/L based on
an uncertainty factor of 10. The Committee observed that the
Environmental Protection Agency for • its suggested drinking water
equivalent level has chosen a factor 15 and are to be able to
balance the dat?. from Yang et al (1983) and the National Academy
of Sciences 1980 conclusion that the safe range of daily selenium
intake if 50 to 200 microgram. The Subcommittee further
recommended that because the Yang et al study and the National
Academy of Sciences recommendation plays such an important role in
the development of the drinking water equivalent level, that more
detail be more redefined concerning these study.
17. Document Analysis a. Descriptors
Metals Subcommittee/ Environmental Health Committee
b. ld*ntifl«r(/Op*n.Cnd*d Terms
c. COSATI Field/Group
II. Availability Statement
19. Security Claaa (Thlt Report)
21. No. of Pa»t
20. Security Claaa (Thlt Pafa)
(See ANSI-Z39.18)
See Instructions on Ravers*
OPTIONAL FORM 272 (4-77)
(Formerly NTIS-35)
Department of Commerce
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UNITED STATES ENVIRONMENTAL PROTECTION AGENCY
WASHINGTON. D.C. 20460
July 19, 1988
OFFICE or
THE ADMINISTRATOR
SAB-EHC-88-037
Honorable Lee M. Thomas
Administrator
U.S. Envorinmental Protection Agency
401 M Street, S.W.
Washington, D.C. 20460
Subject: Science Advisory Board's review of the SELENIUM health
criteria document
Dear Mr. Thomas:
The Metals Subcommittee of the Science Advisory Board's
Environmental Health Committee has completed its review of the
Drinking Water Health Criteria Document for Selenium dated
December 1986^'The review was conducted January 14-15, 1988 at
the St. James Hotel in Washington, D.C. The Subcommittee made
two recommendations; viz, 'that more information was needed in the
document on the studies on which the standard is based and that
the DWEL should be 200 micrograms/L based on an uncertainty
factor of 10.
conclusion in the criteria document that the Drinking
Water Equivalent Level (DWEL) should be 107 micrograms/L is based
mainly on the Yang et al (1983) study and the National Academy of
Sciences (HAS) 1980 conclusion that the safe and adequate range
of daily selenium intake is 50-200 micrograms. One justification
for setting the DWEL at this level is that drinking an average of
2 liters per day would provide close to the upper limit of 200
micrograms per day. To arrive at this conclusion it was
necessary to set the uncertainty factor at 15, a somewhat unusual
value but the only one that would allow both the use of the Yang
et al study and also give an allowable intake close to the upper
limit of the NAS recommendation.
The report properly focuses on the selenium dilemma: the
apparently narrow margin between minimal daily intakes required
to maintain health and intakes associated with toxicity. The
primary source of data for establishing the DWEL is the report of
Yang et al (1983) . The Subcommittee recommends that this report
be discussed at greater length because of the reliance placed
upon it. For example, the authors discuss two areas labelled as
high selenium areas. In one, selenosis was common in livestock
and toxic signs were apparent in humans. In the other, selenosis
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"has naver been reported. In the tables, however, the first area
is seen to be associated with hair and blood levels about eight
times higher that measured in the second. If 3.2 mg/day of
selenium is estimated as the LOAEL, based or. the first area, then
400 ug/day would represent a level below the NOEL. To be
consistent, then, the language in the document should reflect the
concept that the National Academy of Scieces figures may
overestimate the uncertainty margin. Morever, even in high
selenium areas, drinking water seems to be an insignificant
contribution to total intake. If Yang et al are correct in their
assertion that the ratio of toxic to minimal blood levels is
about 16, a figure not too deviant from the NAS value, then the
uncertainty factor could be set to 5-10 without compromising
safety and without jeopardizing a possibly useful source of this
essential element. Also, the 70 kg standard EPA human is
probably not representative of the Chinese population, another
margin in the uncertainty calculation.
Because the Yang et al study and the NAS recommendation play
such an important role in the development of the DWEL, it is
recommended that more detail be provided regarding the studies.
The Yang et al study is not clearly described in the criteria
document and it is not clear what the minimum daily intake of
3200 micrograms/day (LOEL) used in deriving the DWEL refers to.
Does the study deal with individuals or geographic areas? How
many people were involved? How was selenium intake measured?
Also more information is needed on how the NAS arrived at its
recommendation of 50-200 microgram daily intake value.
A second recommendation is that the USEPA consider raising
the DWEL to 160 micrograms/L by using an uncertainty factor of 10
instead of 15. Rounding off to one significant figure could lead
to a DWEL of 200 micrograms/L. The reasons for this are as
follows:
1. In the Yang et al study the LOEL was 3200 micrograms per
day and no lower values have been reported. !
2. A statement on page VI-30 that chronic human ingestion
of 200 micrograms per day may be related to increased incidence
of symptoms is not supported by any of the data presented other
than the NAS report.
3. A daily intake of 214 micrograms (107 micrograms/L x 2
L/day) is too close to the value needed for human nutrition (50-
200 micrograms per day) and too far from the lowest value at
which human symptoms occur.
4. There is little or no evidence for proposed human health
effects such as cancer or teratogenic effects. Selenium (SeS2+)
is not regarded as a human carcinogen.
5. Uncertainty factors should reflect likely beneficial
effects as well as harmful effects. There is limited evidence
that selenium deficiency is related to cancer and perhaps
cardiovascular disease.
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Sincerely,
Norton .Nelson, Chairman
Executive Committee
Richard A. Griesemer, Chairman
Environmental Health Committee
Bernard Weiss, Chairman
Metals Subcommittee
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!:e:als b'ubcemr.iccee
Dr. Bernard \ieiss [Chair], Professor, Division of Toxicology, P.O. Box
KBB, University or Rochester, School of Medicine, Rochester, MY 14642
(716) 275-3791
Dr. Ronald Wyzga [Vice-chair], Electric Power Research Institute, 3412
Hillvieu Avenue, P.O. Box 1041, Palo Alto, California 94303 (415) 855-2577
Dr. Thomas Clarkson, Professor and Head, Division of Toxicology, University
ot Rochester, School of lledicine, Post Office Box RBB, Rochester, New York
14642 (716) 275-3911
Dr. Gary Diamond, Assistant Professor of Pharmacology, University ot
Rochester School of Medicine, Rochester, New York 14642 (716) 275-5250
Dr. Phil Enterline [LNVIKOMIENTAL HEALTH CCttllTTEE], Department of Biostatistics,
Graduate School of Public health, University of Pittsburg, 13U Desoto Street,
Pittsburgh, PA 15261 (412) 624-3032
Dr. Robert Goyer, Department of Pathology, Health Sciences Centre, University
of Western Ontario, London, Ontario, Canada N6A5C1
• •
Dr. liarvin Kuschner, Dean, School of lledicine, Health Science Center,
Level 4, State University of New York, Stony Brook, New York 11794
(516) 444-208U
Dr. Brooke T. Mossman, Department of Pathology, The University of Vermont,
Medical Alumni Building, Burlington, Vermont 05405-0068 (802) 656-2210
Dr. Gunter Oberdoerster, Associate Professor, Radiation Biology and
Biophysics Division, University of Rochester, School of Medicine, 400 ,
Elmwood Avenue, Rochester, N.Y. 14642 (716) 275-3804
Dr. F. William Sunderman, Professor of Laboratory tiedicine and Pharmacology
and head, Department of Laboratory Medicine, University of Connecticut
Health Center, Room C 2021, Farmington, Connecticut 06032 (203) 674-2328
Executive Secretary
Dr. Richard Cothern, Executive Secretary, Environmental Health Committee,
Science Advisory Board [A-101F], U.S. Environmental Protection Agency,
Washington, D.C. 20460 (202)382-2552
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