Diflubenzuron (CASRN 35367-38-5)
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0227
Diflubenzuron;
CASRN 35367-38-5
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 Diflubenzuron
File First On-Line 09/30/1987
Category (section) |
Status |
Last Revised |
---|---|---|
Oral RfD Assessment (I.A.) | on-line | 09/01/1990 |
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 — Diflubenzuron
CASRN — 35367-38-5
Last Revised — 09/01/1990
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 |
---|---|---|---|---|
Methemoglobin and One-Year Dog Feeding Duphar, 1985 |
NOEL: 2 mg/kg/day LEL: l0 mg/kg/day |
l00
|
1
|
2E-2
mg/kg/day |
*Conversion Factors -- none
__I.A.2. Principal and Supporting Studies (Oral RfD)
B.V. Duphar. 1985. MRID No. 00146147. Available from EPA. Write to FOI, EPA, Washington, DC 20460.
Groups of beagle dogs (6 males and 6 females/dose group, l2 males and l2 females in the control group) were given diflubenzuron in gelatin capsules in doses equal to 0, 2, l0, 50, or 250 mg/kg/day for 52 weeks. All animals were observed daily for toxicity. Food consumption was determined daily, and body weights were measured weekly. Hematology, urinalysis, and clinical chemistry investigations were conducted routinely throughout the study. All animals were subjected to complete gross and histopathologic evaluation, ophthalmologic examination, and organ weight determinations. The percent of methemoglobin and sulfhemoglobin increased significantly at l0 mg/kg/day.
__I.A.3. Uncertainty and Modifying Factors (Oral RfD)
UF — An uncertainty factor of l00 was used to account for inter- and intraspecies differences.
MF — None
__I.A.4. Additional Studies/Comments (Oral RfD)
Data Considered for Establishing the RfD:
1) 1-Year Feeding - dog: Principal study - see previous description; core grade guideline
2) 2-Year Feeding (oncogenic) - rat: NOEL=2 mg/kg/day (for methemoglobin and sulfhemoglobin), LEL=8 mg/kg/day; core grade supplementary (Thompson-Hayward Chemical Co., 1973)
3) 2-Year Feeding (oncogenic) - rat: LEL=7.8 mg/kg/day (methemoglobin and sulfhemoglobin formation; core grade guideline [oncogenicity]; core grade supplementary for chronic toxicity (Duphar, 1984)
Note: Together studies 2 and 3 provide sufficient oncogenic and long-term data in rats.
4) 13-Week Feeding - dog: NOEL=l mg/kg/day; LEL=4 mg/kg/day (elevated SGPT and SAP and increased methemoglobinemia); core grade guideline (Thompson- Hayward Chemical Co., 1974)
5) 3-Generation Reproduction - rat: NOEL=8 mg/kg/day [HDT]; core grade guideline (Thompson-Hayward Chemical Co., 1975a)
6) Teratology - rat: Maternal, Fetotoxic, and Teratogenic NOEL=4 mg/kg/day [HDT]; Maternal, Fetotoxic, and Teratogenic LEL=none; core grade guideline (Thompson-Hayward Chemical Co., 1975b)
7) Teratology - rabbit: Maternal, Fetotoxic, and Teratogenic NOEL=4 mg/kg/day [HDT]; Maternal, Fetotoxic, and Teratogenic LEL=none; core grade guideline (Thompson-Hayward Chemical Co., 1975c)
Other Data Reviewed:
l) Lifetime Feeding/Oncogenic - mice: NOEL=2.4 mg/kg/day; LEL=12 mg/kg/day (methemoglobin and sulfhemoglobin); core grade guideline
Data Gap(s): None
__I.A.5. Confidence in the Oral RfD
Study — High
Database — High
RfD — High
The principal study is of excellent quality and is given a high confidence rating. Other data are very supportive and, therefore, the database is given a high confidence rating. High confidence in the RfD follows.
__I.A.6. EPA Documentation and Review of the Oral RfD
Pesticide Registration Standard (l985)
Pesticide Registration Files/Data Evaluation Record
Agency Work Group Review — 08/05/1986
Verification Date — 08/05/1986
__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 — Diflubenzuron
CASRN — 35367-38-5
Not available at this time.
_II. Carcinogenicity Assessment for Lifetime Exposure
Substance Name — Diflubenzuron
CASRN — 35367-38-5
Not available at this time.
_III.
[reserved]
_IV. [reserved]
_V. [reserved]
_VI. Bibliography
Substance Name — Diflubenzuron
CASRN — 35367-38-5
Last Revised — 09/01/1990
_VI.A. Oral RfD References
Duphar, B.V. 1984. MRID No. 00097999. Available from EPA. Write to FOI, EPA, Washington, DC 20460.
Duphar, B.V. 1985. MRID No. 00146147. Available from EPA. Write to FOI, EPA, Washington, DC 20460.
Thompson-Hayward Chemical Company. 1973. MRID No. 00044329, 0006120, 00064921, 00099712. Available from EPA. Write to FOI, EPA, Washington, DC 20460.
Thompson-Hayward Chemical Company. 1974. MRID No. 00038706, 00099687. Available from EPA. Write to FOI, EPA, Washington, DC 20460.
Thompson-Hayward Chemical Company. 1975a. MRID No. 00044330. Available from EPA. Write to FOI, EPA, Washington, DC 20460.
Thompson-Hayward Chemical Company. 1975b. MRID No. 00044326. Available from EPA. Write to FOI, EPA, Washington, DC 20460.
Thompson-Hayward Chemical Company. 1975c. MRID No. 00044327. Available from EPA. Write to FOI, EPA, Washington, DC 20460.
_VI.B. Inhalation RfD References
None
_VI.C. Carcinogenicity Assessment References
None
_VII. Revision History
Substance Name — Diflubenzuron
CASRN — 35367-38-5
Date |
Section |
Description |
---|---|---|
09/01/1990 | I.A. | Principal study clarified |
09/01/1990 | I.A.4. | Citations added |
09/01/1990 | VI. | Bibliography on-line |
01/01/1992 | IV. | Regulatory actions updated |
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. |
12/10/1998 | I., II. | This chemical is being reassessed under the IRIS Program. |
02/09/2004 | I., II. | This chemical is no longer being reassessed under the IRIS Program. See Federal Register February 9, 2004 (Volume 69, Number 26). |
_VIII. Synonyms
Substance Name — Diflubenzuron
CASRN — 35367-38-5
Last Revised — 09/30/1987
- 35367-38-5
- BENZAMIDE, N-(((4-CHLOROPHENYL)AMINO)CARBONYL)-2,6-DIFLUORO-
- 1-(4-CHLOROPHENYL)-3-(2,6-DIFLUOROBENZOYL)UREA
- Diflubenzuron
- DIFLURON
- DIMILIN
- DU 112307
- ENT 29054
- N-(((4-CHLOROPHENYL)AMINO)CARBONYL)-2,6-DIFLUOROBENZAMIDE
- OMS 1804
- PDD 6040I
- PH 60-40
- TH 6040