Biomedical Engineering Reference
In-Depth Information
If one compares the results of the three NEDO chronic inhalation
studies conducted in monkeys, rats, and mice, the monkeys show effects
at lower doses than the rat or mouse. The LOAEL is 10 ppm in monkeys,
because of slight pathological changes in the nervous system and
1000 ppm in rats and mice because of slight changes in body and
organ weights that may be treatment related.
4.5.4 Dogs
In an early inhalation study, four dogs were exposed to 450-500 ppm
methanol for 8 hours per day 7days per week for 1 year. Hematogical,
clinical signs, and ophthalmic exams were conducted. No adverse
effects were reported (Sayers et al., 1942).
In another early limited inhalation study, two dogs were exposed
at about 10,000 ppm methanol for about 3 minutes at hourly interval
(8 time daily) for 100 days. Both dogs survived and show no clinical
sign of treatment. Ophthalmic findings were negative (Sayers et al.,
1944).
4.6 REPEAT EXPOSURE—ORAL
4.6.1 Rats
USEPA conducted a 90-day subchronic oral study in Sprague Dawley
rats. Thirty rats per sex per dose were gavaged with 0, 100, 500, or
2500mg/kg bw of methanol per day. Ten per sex per dose were
sacrificed after 6 weeks. The remaining rats were scarified at the
end of the study. Weekly body weights, food consumption, clinical
signs of toxicity, opthalmological evaluation, and mortality were eval-
uated through out the study. Evaluation of blood, urine chemistry, gross,
and microscopic tissue were conducted at sacrifice.
Brain weights were significantly less than the control at the high dose
(2500mg/kg). A slight but not statistically significant elevation of liver
weight and liver enzymes (SGPT, SAP) were also noted in both male
and female rats exposed at 2500mg/kg. However, no treatment-related
