Baythroid (CASRN 68359-37-5)
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0132
Baythroid;
CASRN 68359-37-5
Health assessment information on a chemical substance is included in IRIS
only after a comprehensive review of chronic toxicity data by U.S. EPA
health scientists from several Program Offices and the Office of Research
and Development. The summaries presented in Sections I and II represent
a consensus reached in the review process. Background information and
explanations of the methods used to derive the values given in IRIS are
provided in the Background Documents.
STATUS OF DATA FOR Baythroid
File First On-Line 03/31/1987
Category (section) |
Status |
Last Revised |
---|---|---|
Oral RfD Assessment (I.A.) | on-line | 03/01/1988 |
Inhalation RfC Assessment (I.B.) | no data | |
Carcinogenicity Assessment (II.) | no data |
_I. Chronic Health Hazard Assessments for Noncarcinogenic Effects
_I.A. Reference Dose for Chronic Oral Exposure (RfD)
Substance Name — Baythroid
CASRN — 68359-37-5
Last Revised — 03/01/1988
The oral Reference Dose (RfD) is based on the assumption that thresholds
exist for certain toxic effects such as cellular necrosis. It is expressed
in units of mg/kg-day. In general, the RfD is an estimate (with uncertainty
spanning perhaps an order of magnitude) of a daily exposure to the human
population (including sensitive subgroups) that is likely to be without
an appreciable risk of deleterious effects during a lifetime. Please refer
to the Background Document for an elaboration of these concepts. RfDs
can also be derived for the noncarcinogenic health effects of substances
that are also carcinogens. Therefore, it is essential to refer to other
sources of information concerning the carcinogenicity of this substance.
If the U.S. EPA has evaluated this substance for potential human carcinogenicity,
a summary of that evaluation will be contained in Section II of this file.
__I.A.1. Oral RfD Summary
Critical Effect |
Experimental Doses* |
UF
|
MF
|
RfD
|
---|---|---|---|---|
Decreased body 2-Year Rat Study, Mobay Chemical, 1983a |
NOEL: 50 ppm LEL: 150 ppm |
100
|
1
|
2.5E-2
mg/kg/day |
*Conversion Factors: l ppm = 0.05 mg/kg/day (assumed rat food consumption)
__I.A.2. Principal and Supporting Studies (Oral RfD)
Mobay Chemical Corporation. 1983a. MRID No. 00137303. Available from EPA.
Write to FOI, EPA, Washington, DC 20460.
Sixty-five male and 65 female Wistar SPF rats, 5-6 weeks of age, were
assigned to four groups which were fed diets containing 0, 50, 150, and 450
ppm of baythroid. Animals were observed for clinical signs twice daily and
once daily on weekends and holidays. Individual body weights and group food
consumption were determined weekly for the first 26 weeks, biweekly during
week 27 through 74, and then weekly until termination. Hematology, clinical
chemistry, and urinalysis were performed on 10 rats/sex/group at 6, 12, 18,
and 24 months of study. Observed results included decreased body weights in
males and inflammatory foci in kidneys of females.
__I.A.3. Uncertainty and Modifying Factors (Oral RfD)
UF — A 100-fold UF has been used to compensate for both the interspecies
differences in extrapolating from the human, and the expected intrahuman
variability to the toxicity of this chemical.
MF — None
__I.A.4. Additional Studies/Comments (Oral RfD)
Data Considered for Establishing the RfD:
1) 2-Year Feeding - rat: Principal study - see previous description; core
grade minimum
2) 1-Year Feeding - dog: NOEL=160 ppm (4 mg/kg/day); LEL=640 ppm (16 mg/kg/day)
(slight ataxia in two dogs, one occasion each; increased vomiting; increased
pasty-to-liquid feces; decreased body weights in males); core grade minimum
(Mobay Chemical, 1983b)
3) 3-Generation Reproduction - rat: Systemic NOEL=50 ppm (2.5 mg/kg/day);
Systemic LEL=150 ppm (7.5 mg/kg/day) (body weight decrease in the pups);
Reproductive NOEL=50 ppm; Reproductive LEL=150 ppm (decreased viability
index); core grade minimum (Mobay Chemical, 1983c)
4) Teratology - rat: Maternal NOEL=3 mg/kg/day; Maternal LEL=10\mg/kg/day
(behavioral changes in gait and coordination); Teratogenic NOEL=30 mg/kg/day
(HDT); Fetotoxic NOEL=30 mg/kg/day (HDT); core grade minimum (Mobay Chemical,
1982)
5) Teratology - rabbit: Maternal NOEL=15 mg/kg/day, Maternal LEL=45\mg/kg/day
(abortion and resorption); Teratogenic NOEL=45 mg/kg/day (HDT); Fetotoxic
NOEL=45 mg/kg/day (HDT); core grade minimum (Mobay Chemical, 1983d)
Other Data Reviewed:
1) 23-Month Feeding (oncogenic) - mice: Systemic NOEL=none; Systemic LEL=50
ppm (7.5 mg/kg/day) (LDT) (increased alkaline phosphatase activity in
males); core grade supplementary (Mobay Chemical, 1983e)
Data Gap(s): None
__I.A.5. Confidence in the Oral RfD
Study — High
Database — High
RfD — High
The principal study appears to be of good quality and is given a high rating. Since there are no data gaps existing for baythroid and additional studies are also of good quality, the database is given a high confidence. High confidence in the RfD follows.
__I.A.6. EPA Documentation and Review of the Oral RfD
Pesticide Registration Files
Agency Work Group Review — 04/08/1986
Verification Date — 04/08/1986
Screening-Level Literature Review Findings — A screening-level review conducted by an EPA contractor of the more recent toxicology literature pertinent to the RfD for Baythroid conducted in September 2002 did not identify any critical new studies. IRIS users who know of important new studies may provide that information to the IRIS Hotline at hotline.iris@epa.gov or (202)566-1676.
__I.A.7. EPA Contacts (Oral RfD)
Please contact the IRIS Hotline for all questions concerning this assessment or IRIS, in general, at (202)566-1676 (phone), (202)566-1749 (FAX) or hotline.iris@epa.gov (internet address).
_I.B. Reference Concentration for Chronic Inhalation Exposure (RfC)
Substance Name — Baythroid
CASRN — 68359-37-5
Not available at this time.
_II. Carcinogenicity Assessment for Lifetime Exposure
Substance Name — Baythroid
CASRN — 68359-37-5
This substance/agent has not undergone a complete evaluation and determination under US EPA's IRIS program for evidence of human carcinogenic potential.
_III.
[reserved]
_IV. [reserved]
_V. [reserved]
_VI. Bibliography
Substance Name — Baythroid
CASRN — 68359-37-5
Last Revised — 11/01/1989
_VI.A. Oral RfD References
Mobay Chemical Corporation. 1982. MRID No. 00131533. Available from EPA.
Write to FOI, EPA, Washington, DC 20460.
Mobay Chemical Corporation. 1983a. MRID No. 00137303. Available from EPA.
Write to FOI, EPA, Washington, DC 20460.
Mobay Chemical Corporation. 1983b. MRID No. 00151358. Available from EPA.
Write to FOI, EPA, Washington, DC 20460.
Mobay Chemical Corporation. 1983c. MRID No. 00131532, 00137545, 00149597.
Available from EPA. Write to FOI, EPA, Washington, DC 20460.
Mobay Chemical Corporation. 1983d. MRID No. 00131534. Available from EPA.
Write to FOI, EPA, Washington, DC 20460.
Mobay Chemical Corporation. 1983e. MRID No. 00137304. Available from EPA.
Write to FOI, EPA, Washington, DC 20460.
_VI.B. Inhalation RfC References
None
_VI.C. Carcinogenicity Assessment References
None
_VII. Revision History
Substance Name — Baythroid
CASRN — 68359-37-5
Date |
Section |
Description |
---|---|---|
11/01/1989 | VI. | Bibliography on-line |
04/01/1997 | III., IV., V. | Drinking Water Health Advisories, EPA Regulatory Actions, and Supplementary Data were removed from IRIS on or before April 1997. IRIS users were directed to the appropriate EPA Program Offices for this information. |
12/03/2002 | I.A.6. | Screening-Level Literature Review Findings message has been added. |
_VIII. Synonyms
Substance Name — Baythroid
CASRN — 68359-37-5
Last Revised — 03/31/1987
- 68359-37-5
- BAY FCR 1272
- Baythroid
- BAYTHROID H
- CYFLUTHRIN