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Chronic Inhalation Exposure of Rats and Rabbits to Nitromethane and 2-Nitropropane.

Ulrich CE; Dorato MA; Ledbetter A; Marold BW; Ward CO

NIOSH 1977 Jan:202 pages

00080945

A study was performed to determine whether the threshold limit values of 100ppm for nitromethane (75525) (NM) and 25ppm for 2- nitropropane (79469) (NP) are acceptable or should be changed. There were five experimental groups, one control and four exposed. Each group consisted of 50 male Sprague-Dawley-rats and 15 male rabbits. Exposure duration was 7 hours per day, 5 days per week for 6 months. NM was evaluated at concentrations of 100 and 750ppm, while NP was evaluated at exposure concentrations of 25 and 200ppm. Various physiologic, serum biochemical, hematologic and histopathologic evaluations were conducted on animals sacrificed after 2 and 10 days and 1, 3, and 6 months of exposure. Rats exposed to 98ppm NM were almost identical in growth rate as compared to controls, while those exposed to 745ppm NM did not gain weight as rapidly as controls. There were no differences in bodyweight gain which could be attributed to the exposure of either 207 or 27ppm NP. Hematocrits from rats exposed to 745ppm NM were slightly depressed at all measurement intervals but not statistically at the 2 day interval. Exposure to 98ppm NM did not alter HCT except at the 10 day interval. Prothrombin time was unaffected except for an isolated depression in 745ppm NM rats sacrificed at 10 days. None of the various hematologic evaluations conducted in rats demonstrated any effects related to NP exposure.

NIOSH-Contract; Contract-210-75-0039; Nitro-compounds; Nitroparaffins; Animal-models; Experimental-methods; Physiologic-effects; Blood-chemistry; Cytopathology; Fumes; Gases; Animals;

75-52-5; 79-46-9;

19770102

Contract;

1977

Contract-210-75-0039

Huntingdon Research Center, New York, New York, NIOSH Contract No. 210-75-0039, 202 pages, 6 references

NY;