Pendimethalin (CASRN 40487-42-1)
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0292
Pendimethalin;
CASRN 40487-42-1
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 Pendimethalin
File First On-Line 06/30/1988
Category (section) |
Status |
Last Revised |
---|---|---|
Oral RfD Assessment (I.A.) | on-line | 02/01/1991 |
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 — Pendimethalin
CASRN — 40487-42-1
Primary Synonym — Prowl
Last Revised — 02/01/1991
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 |
---|---|---|---|---|
Increase in serum 2-Year Dog Feeding American Cyanamid, |
NOEL: 12.5 mg/kg/day LEL: 50 mg/kg/day |
300
|
1
|
4E-2
mg/kg/day |
*Conversion Factors and Assumptions — none
__I.A.2. Principal and Supporting Studies (Oral RfD)
American Cyanamid Co. 1979. MRID No. 00058657. Available from EPA. Write to FOI, EPA, Washington, DC 20460.
Purebred beagle dogs, 4/sex/dose, were fed pendimethalin 7 days a week by gelatin capsule at 0, 12.5, 50, and 200 mg/kg/day. Clinical chemistry findings were considered within normal limits for all dose levels however, serum alkaline phosphatase (SAP) was increased at the mid- and high-dose levels. Liver weights were increased and the liver showed lesions consisting of inflammation and hemosiderosis at the mid- and high-dose levels. The NOEL and LEL for systemic toxicity are 12.5 and 50 mg/kg/day, respectively, based on hepatic lesions and an increase in SAP and liver weights.
__I.A.3. Uncertainty and Modifying Factors (Oral RfD)
UF — An uncertainty factor of 100 was used to account for the inter- and intraspecies differences. An additional UF of 3 was used to account for the lack of an acceptable long term study in a second species. A factor of 3 was chosen rather than 10 since the studies at hand, although of insufficient quality, indicate that the dog is the more sensitive species, and since there is no significant difference in subchronic and chronic effects for this chemical.
MF — None
__I.A.4. Additional Studies/Comments (Oral RfD)
Data Considered for Establishing the RfD:
1) 2-Year Feeding - dog: Principal study - see previous description; core grade minimum (American Cyanamid Co., 1979a)
2) 3-Generation Reproduction - rat: Reproductive NOEL=500 ppm (25 mg/kg/day); Reproductive LEL=5000 ppm (250 mg/kg/day) (HDT; reduced litter size, survival index, and pup weight); core grade minimum (American Cyanamid Co., 1974a)
3) Teratology - rat: Fetotoxic and Teratogenic NOEL=500 mg/kg/day (HDT); core grade guideline (American Cyanamid Co., 1979b)
4) Teratology - rabbit: NOEL=60 mg/kg/day (HDT); core grade minimum (American Cyanamid Co., 1982)
Other Data Reviewed:
1) 90-Day Feeding - rat: NOEL=500 ppm (25 mg/kg/day); LEL=5000 ppm (250 mg/kg/day) (decrease in hematocint and hemoglobin in males, decreased body weight and food consumption, hypertrophy of the liver accompanied by increased liver weights); core grade guideline (American Cyanamid Co., 1974b)
2) 90-Day Feeding - dog: NOEL=2500 ppm (62.5 mg/kg/day) (by gavage); no core grade (American Cyanamid Co., 1973)
Data Gap(s): Chronic Rat Feeding Study
__I.A.5. Confidence in the Oral RfD
Study — Medium
Database — Medium
RfD — Medium
The critical study appears to be of good quality and is given a medium confidence rating. Since the database on chronic toxcity is supportive but incomplete, the database is given a medium confidence rating. Medium confidence in the RfD follows.
__I.A.6. EPA Documentation and Review of the Oral RfD
Source Document — This assessment is not presented in any existing U.S. EPA document.
Other EPA Documentation — Pesticide Registration Standard, September 1984; Pesticide Registration Files
Agency Work Group Review — 08/19/1986, 09/16/1987
Verification Date — 09/16/1987
__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 — Pendimethalin
CASRN — 40487-42-1
Primary Synonym — Prowl
Not available at this time.
_II. Carcinogenicity Assessment for Lifetime Exposure
Substance Name — Pendimethalin
CASRN — 40487-42-1
Primary Synonym — Prowl
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 — Pendimethalin
CASRN — 40487-42-1
Primary Synonym — Prowl
Last Revised — 02/01/1991
_VI.A. Oral RfD References
American Cyanamid Company. 1973. MRID No. 00026672, 00040305, 00106763. Available from EPA. Write to FOI, EPA, Washington, DC 20460.
American Cyanamid Company. 1974a. MRID No. 00026671, 00059470, 00106762. Available from EPA. Write to FOI, EPA, Washington, DC 20460.
American Cyanamid Company. 1974b. MRID No. 00026667, 00026668, 00040302. Available from EPA. Write to FOI, EPA, Washington, DC 20460.
American Cyanamid Company. 1979a. MRID No. 00058657. Available from EPA. Write to FOI, EPA, Washington, DC 20460.
American Cyanamid Company. 1979b. MRID No. 00025752. Available from EPA. Write to FOI, EPA, Washington, DC 20460.
American Cyanamid Company. 1982. MRID No. 00117444. 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 — Pendimethalin
CASRN — 40487-42-1
Primary Synonym — Prowl
Date |
Section |
Description |
---|---|---|
02/01/1991 | I.A. | Text edited |
02/01/1991 | VI. | Bibliography on-line |
01/01/1992 | IV. | Regulatory Action section 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. |
12/10/1998 | I.A., II. | This chemical is being reassessed under the IRIS Program. |
02/09/2004 | I.A., 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 — Pendimethalin
CASRN — 40487-42-1
Primary Synonym — Prowl
Last Revised — 06/30/1988
- 40487-42-1
- AC 92553
- ANILINE, 3,4-DIMETHYL-2,6-DINITRO-N-(1-ETHYLPROPYL)-
- BENZENAMINE, 3,4-DIMETHYL-2,6-DINITRO-N-(1-ETHYLPROPYL)-
- BENZENAMINE, N-(1-ETHYLPROPYL)-3,4-DIMETHYL-2,6-DINITRO-
- HERBADOX
- HORBADOX
- N-(1-AETHYLPROPYL)-3,4-DIMETHYL-2,6-DINITROANILIN
- N-(1-AETHYLPROPYL)-2,6-DINITRO-3,4-XYLIDIN
- N-(1-ETHYLPROPYL)-3,4-DIMETHYL-2,6-DINITRO- BENZENAMINE
- N-(3-PENTYL)-3,4-DIMETHYL-2,6-DINITROANILINE
- PAY-OFF
- Pendimethalin
- PENDIMETHALINE
- PENOXALIN
- PENOXALINE
- PENOXYN
- PHENOXALIN
- Prowl
- STOMP
- STOMP 330D
- STOMP 330E
- TENDIMETHALIN
- 3,4-XYLIDINE, 2,6-DINITRO-N-(1-ETHYLPROPYL)-