[Acute effects of methyl bromide gas in rats and mice--studies on survival time]

Wistar male rats and ddY male mice were exposed to 500-10,000 ppm of methyl bromide gas up to 8 hours, and the survival time and weights of brain, lung, liver, kidneys, spleen and tests were measured. The survival time decreased with the gas concentration almost exponentially. In general, rats had a longer survival time than mice under the same exposure concentration. Difference of survival time between rats and mice was remarkable at low concentrations but small at high concentrations. Spleen weight decreased significantly and kidney weights tended to increase at 2000 ppm or greater exposure concentrations. Difference between wet and dry lung weight in the exposure group was significantly greater than that in the control group, especially for high concentrations, which suggested pulmonary edema or bronchopneumonia.