Biomedical Engineering Reference
In-Depth Information
2000 and 3000 ppm and 7 months at 1000 ppm. Recovery time (no
exposure) was 1 and 4 months for monkeys exposed at 5000 ppm,
6 months for monkeys exposed at 3000 ppm, and 12 months for monkeys
exposed at 2000 ppm, and 1 and 6 months for monkeys exposed at
1000 ppm. Parameters evaluated effects on vision, body weight, clinical
signs, hematology, histopathology clinical chemistry, and survival.
The results showed that the monkeys tolerated 1000, 2000, and
3000 ppm methanol, but 5000 ppm levels resulted in reduced move-
ment, vomiting, and dyspnea. Exposure to 2000 ppm and higher
methanol resulted in reduced blood pH during exposure but the blood
pH recovered to normal during the recovery period. Pathological
changes in the nervous system were noted at all test levels during
exposure. Slight partial atrophy of the optic nerve was noted at
3000 ppm and higher but according to the author it was questionable
if it was treatment related. No treatment related effects on vision, body
weight, clinical signs, hematology, histopathology, and clinical chem-
istry were reported. One death was reported at day 5 in a monkey
exposed at 5000 ppm. The NOAEL was
<
1000 ppm and the LOAEL
was 1000 ppm based on pathological changes in the nervous system.
In a chronic inhalation study, monkeys were exposed to 0, 10, 100, or
1000 ppm methanol for 22 hours per day for a maximum of 2.5 years
(NEDO, 1986, 1987). Eight monkeys were exposed at each level. Two
monkeys at each treatment level (one in control) were sacrificed after
7 months of exposure. Three monkeys at each treatment level (two in
control) were sacrificed after 19months of exposure. The remainder three
per group were sacrificed at 2.5 years. Parameters evaluated effects on
vision, body weight, clinical signs, hematology, histopathology clinical
chemistry, and survival. In the animals sacrificed after 7 months of
exposure, no clinical signs were noted, but fatty degeneration of the liver
at animal exposed at 100 or 1000 ppm methanol were observed. Slight
pathological changes in the nervous system (hyperplasia of reactive
astroglias in the white matter) were noted at the 7 month sacrifice in
all treated animals. In the 1000 ppmmonkey, slightly abnormal ECG and
decreased blood pH were noted after 7 months of exposure. Histopatho-
logical examination after 19 months showed slight nervous system and
liver effects at all
treatment
levels. Some nervous system effects
