Endothall (CASRN 145-73-3)
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0155
Endothall;
CASRN 145-73-3
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 Endothall
File First On-Line 03/31/1987
Category (section) |
Status |
Last Revised |
---|---|---|
Oral RfD Assessment (I.A.) | on-line | 03/01/1991 |
Inhalation RfC Assessment (I.B.) | no data | |
Carcinogenicity Assessment (II.) | no data | 09/01/1991 |
_I. Chronic Health Hazard Assessments for Noncarcinogenic Effects
_I.A. Reference Dose for Chronic Oral Exposure (RfD)
Substance Name — Endothall
CASRN — 145-73-3
Last Revised — 03/01/1991
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
|
---|---|---|---|---|
Increased absolute Two-Year Feeding Pennwalt Agchem., 1965 |
NOEL: 100 ppm (diet) mg/kg bw/day) LEL: 300 ppm (diet) (6 mg/kg bw/day) |
100
|
1
|
2E-2
mg/kg/day |
*Conversion Factors and Assumptions — Dose adjusted for assumed dog food consumption (2.5% bw/day) and expressed as endothall ion.
__I.A.2. Principal and Supporting Studies (Oral RfD)
Pennwalt Agchem. 1965. MRID No. 00101735. Available from EPA. Write to FOI, EPA, Washington, DC 20460.
Three male and 3 female dogs were administered diets that initially contained 0, 100, 300 or 800 ppm of disodium endothall. The concentration in the high- dose group was gradually increased over months 19-22 to a final concentration of 2000 ppm. The doses were calculated on the basis of the amount of endothall ion in the diet, and the standard equivalence factor for dogs (0.025 kg of diet/kg of bw/day). No effect on weight gain, hematology, BSP clearance, SGOT or urinalysis was noted. At necropsy, increased absolute and relative weights of stomach and small intestine were noted in intermediate and high-dose dogs. Increased "mucosal gland activity" was noted in the stomachs of high-dose dogs, along with slight edema of the pyloric region.
__I.A.3. Uncertainty and Modifying Factors (Oral RfD)
UF — An uncertainty factor of 100 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) Two-Year Feeding - dog: Principal study - see previous description; no core grade
2) 3-Generation Reproduction - rat: NOEL=100 ppm (5 mg/kg/day); LEL=2500 ppm (125 mg/kg/day) [weight loss, kidney and adrenal discoloration, F2B pup mortality (dose discontinued)]; core grade minimum (Pennwalt Corp., 1965)
3) 2-Year Feeding (oncogenic) - rat: Systemic NOEL=2500 ppm (125 mg/kg/day) (HDT); no core grade (only 10 animals/sex were used) (Pennwalt Corp., 1977)
4) Teratology with postnatal phase - rat: Maternal NOEL=10 mg/kg/day; Maternal LEL=20 mg/kg/day (death); Fetotoxic NOEL=10\mg/kg/day; Fetotoxic LEL=40 mg/kg/day (increased number of skeletal variations); core grade minimum (Pennwalt Corp., 1982)
5) Teratology - mouse: Teratogenic NOEL=20 mg/kg/day; Teratogenic LEL= 40 mg/kg/day (HDT) (skeletal malformations noted at HDT with maternal toxicity); Maternal NOEL=5 mg/kg/day; Maternal LEL=20\mg/kg/day (death); Fetotoxic NOEL=20 mg/kg/day; Fetotoxic LEL=40\mg/kg/day (skeletal anomalies); core grade minimum (Pennwalt Corp., 1981)
6) 6-Week Feeding - dog: NOEL=10 mg/kg/day; LEL=20\mg/kg/day (100% mortality at this dose level and higher; congested and edematous stomachs with occasional erosion and hemorrhage); no core grade (Pennwalt Corp., 1953)
Data Gap(s): Chronic Rat Feeding Study (repeat study in progress)
__I.A.5. Confidence in the Oral RfD
Study — Medium
Database — Medium
RfD — Medium
The critical study appears to be of fair quality and is given a medium confidence rating. The database is generally supportive but since there is a data gap existing for endothall, the database is also given a medium confidence rating. Medium confidence in the RfD follows.
__I.A.6. EPA Documentation and Review of the Oral RfD
Pesticide Registration Files
Agency Work Group Review — 04/22/1986, 11/25/1986
Verification Date — 11/25/1986
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 Endothall conducted in September 2002 identified one or more significant new studies. IRIS users may request the references for those studies from 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 — Endothall
CASRN — 145-73-3
Not available at this time.
_II. Carcinogenicity Assessment for Lifetime Exposure
Substance Name — Endothall
CASRN — 145-73-3
Not available at this time.
_III.
[reserved]
_IV. [reserved]
_V. [reserved]
_VI. Bibliography
Substance Name — Endothall
CASRN — 145-73-3
Last Revised — 07/01/1992
_VI.A. Oral RfD References
Pennwalt Agchem. 1965. MRID No. 00101735. Available from EPA. Write to FOI, EPA, Washington, DC 20460.
Pennwalt Corporation. 1953. MRID No. 00040962. Available from EPA. Write to FOI, EPA, Washington, DC 20460.
Pennwalt Corporation. 1965. MRID No. 00084610. Available from EPA. Write to FOI, EPA, Washington, DC 20460.
Pennwalt Corporation. 1977. MRID No. 00084609. Available from EPA. Write to FOI, EPA, Washington, DC 20460.
Pennwalt Corporation. 1981. MRID No. 00073371, 00085940. Available from EPA. Write to FOI, EPA, Washington, DC 20460.
Pennwalt Corporation. 1982. MRID No. 00118952. 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 — Endothall
CASRN — 145-73-3
Date |
Section |
Description |
---|---|---|
03/01/1991 | I.A.4. | Citations added |
03/01/1991 | VI. | Bibliography on-line |
09/01/1991 | II. | Carcinogenicity assessment now under review |
01/01/1992 | IV. | Regulatory Action section on-line |
07/01/1992 | III.A. | Health Advisory on-line |
07/01/1992 | VI.D. | Health Advisory references on-line |
08/01/1992 | III.A.5. | Text clarified |
08/01/1995 | II. | EPA's RfD/RfC and CRAVE workgroups were discontinued in May, 1995. Chemical substance reviews that were not completed by September 1995 were taken out of IRIS review. The IRIS Pilot Program replaced the workgroup functions beginning in September, 1995. |
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 — Endothall
CASRN — 145-73-3
Last Revised — 03/31/1987
- 145-73-3
- AQUATHOL
- 1,2-CYCLOHEXANEDICARBOXYLIC ACID, 3,6-endo-EPOXY-
- 3,6-ENDOOXOHEXAHYDROPHTHALIC ACID
- ENDOTHAL
- Endothall
- ENDOTHAL TECHNICAL
- 3,6-ENDOXOHEXAHYDROPHTHALIC ACID
- HYDOUT
- HYDROTHAL-191
- HYDROTHAL-47
- 7-OXABICYCLO(2.2.1)HEPTANE-2,3-DICARBOXYLIC ACID
- PHTHALIC ACID, HEXAHYDRO-3,6-endo-OXY-
- RCRA WASTE NUMBER P088
- TRI-ENDOTHAL