2-nitropropane

Toxicity to reproduction: other studies

Administrative data

Endpoint:

toxicity to reproduction: other studies

Type of information:

experimental study

Adequacy of study:

supporting study

Study period:

1980-81

Reliability:

2 (reliable with restrictions)

Rationale for reliability incl. deficiencies:

other: No data on GLP, animals were not mated. Incidences of findings in controls and treated animals were not tabulated (and therefore could not be examined). The result listed under the "result" heading was written in the text.

Data source

Reference

Reference 1

Reference Type:

publication

Title:

Histologic study of tissues and organs from rats exposed to vapors of 2-nitropropane at 25 ppm

Author:

Griffin TB, Stein AA and Coulston F.

Year:

1981

Bibliographic source:

Ecotox Environ Safety 5:194-201

Reference 2

Reference Type:

publication

Title:

Chronic inhalation exposure of rats or vapors of 2-nitropropane at 25 ppm

Author:

Griffin TB, Coulston F and Stein AA.

Year:

1980

Bibliographic source:

Ecotox and Environ Safety. 4: 267-281

Materials and methods

Test guideline

Qualifier:

no guideline followed

GLP compliance:

not specified

Type of method:

other: examination of reproductive organs from chronic toxicity study

Test material

Test material information

Constituent 1

Reference substance name:

2-nitropropane

EC Number:

201-209-1

EC Name:

2-nitropropane

Cas Number:

79-46-9

Molecular formula:

C3H7NO2

IUPAC Name:

2-nitropropane

Details on test material:

Purity of the test material was 95.65 % (by weight). It also contained 3.63% 1-nitropropane, 0.20% nitroethane, 0.51% 2-nitro-2-methylpropane and 0.01% water.

Test animals

Species:

rat

Strain:

Sprague-Dawley

Sex:

male/female

Details on test animals or test system and environmental conditions:

Two hundred fifty CRL: COBS CD SD BR rats per sex were used in the study. The initial weights and ages were not listed. Rats were acclimated for an unlisted amount of time. All animals were allowed free access to food and water (except during exposure, when food and water were withheld from both controls and exposed animals). The animals were randomly allocated to an exposure group of 125 animals/sex and a control group of 125 animals/sex.

Administration / exposure

Route of administration:

inhalation: vapour

Type of inhalation exposure (if applicable):

whole body

Vehicle:

unchanged (no vehicle)

Details on exposure:

Vapors were generated by bubbling purified nitrogen through the test material in an all-glass vessel maintained in a thermostatted water bath (45 degrees C). The test material in the generator was maintained at a constant level. After each week of operation the remaining test material was discarded and replaced with fresh material. Analyses of the test material remaining after one week showed that the material did not decompose. The effluent from the vapor generator was injected into a section of the chamber containing a large circulating fan that mixed the effluent with air from the inatake air duct. An exhaust blower was operated at a velocity sufficient to provide 15 air changes/hour.

Analytical verification of doses or concentrations:

yes

Details on analytical verification of doses or concentrations:

Concentrations of vapors in the exposure chambers were monitored by frequent sampling. Routinely, at least 3 air samples were obtained daily by means of an air-sampling pump operated with a limiting orifice to control flow rate The air from the chamber was withdrawn through two glass impingers aligned in series, filled with ethyl acetate, and immersed in an ice bath. Studies demonstrated that approximately 99% of the test material was trapped in the first impinger. After a suitable sampling period, the contents of the impingers were transferred to a volumetric flask and a known quantity of 1-nitropropane was added as an internal standard. After dilution to volume, an aliqout was injected into a gas chromatograph and compared with standards. The mean concentration of test material was 25 +/- 1 ppm. This was equivalent to 78 mg/m3.

Duration of treatment / exposure:

7 hours/day

Frequency of treatment:

5 days/week for 22 months

Duration of test:

22 months

Doses / concentrations

Doses / concentrations 1

Remarks:

Doses / Concentrations:
0, 25 ppm
Basis:
nominal conc.

Doses / concentrations 2

Remarks:

Doses / Concentrations:
0, 25 +/- 1 ppm
Basis:
analytical conc.

No. of animals per sex per dose:

125/sex

Control animals:

yes

Details on study design:

: Groups of 125 animals/sex were exposed to 25 ppm, 7 hours/day, 5 days/week for 22 months in an 8 x 8 x 12 foot chamber. The control group was housed in a room having environmental conditions similar to those in the exposure chamber. All animals were observed daily for signs of toxicity. Each animal was weighed weekly.

Ten animals per sex per group were euthanized at the following intervals: one month, 3 months, 9 months and 12 months. Ten animals per group also were euthanized at 6 months, with the exception of exposed males (N= 9). Sixty two and 44 control males and females (respectively) were euthanized at 22 months. Twenty seven and 29 exposed males and females (respectively) were euthanized at 22 months. Additional groups of 6 males and 8 females, and 7 males and 9 females were exposed to test material for 3 or 12 months (respectively) and euthanized at 22 months.

Body weights were obtained at termination. All animals that died or survived to termination were given complete necropsies. Specimens of prostate, seminal vesicle, testis, uterus, ovary and any lesions or tumors were obtained from each of the rats and processed for histological examination.

Statistics:

Where appropriate, a Student's t test was used to compare treatment group means against controls

Results and discussion

Effect levels

Dose descriptor:

NOAEL

Remarks:

reproductive organ toxicity

Effect level:

25 ppm (analytical)

Sex:

male/female

Observed effects

There was no evidence of any lesion or onset of any disease in any organ examined that could be attributed to test material exposure. Therefore, 25 ppm is a NOAEL for reproductive organ toxicity.

Any other information on results incl. tables

This study is described in greater detail in Section 7.5.3.  Only the test conditions and results pertinent to reproductive organs are listed in this summary

Applicant's summary and conclusion

Conclusions:

Negative- There was no evidence of any lesion or onset of any disease in any organ examined that could be attributed to test material exposure. Therefore, 25 ppm is a NOAEL for reproductive organ toxicity.