Abstract
People working under the manhole and in confined spaces such as tanks and others are at the risk of being exposed to high rate of death due to lack of oxygen. Therefore, we investigated activity change of SD rats and lethal concentrations resulting from the concentration rate of oxygen using inhalation chamber and nitrogen gas as well as oxygen to analyze the causes and prevent accidents by finding out the lethal concentrations resulting from the oxygen concentration rates. SD male rats were divided into 4 groups and each of the group with 10 rats were exposed to a confined space with 4%, 5%, 6% and 7% oxygen concentration rates respectively. We investigated activity change of test animals using ultraviolet detector and identifying when the rats died and what the lethal concentrations were at that moment during 4 hours or 240 minutes before taking the time to recover for the rats for 48 hours. We confirmed that the rats in the space with lack of oxygen got increasingly active but they showed decreased activity after the first fifty minutes. They recover in terms of their activity after being exposed to space with 21% of oxygen rate for four hours. The fatality rate for the rats was 100% at 4% oxygen concentration within fifty minutes; 90% at 5% oxygen concentration within 230 minutes; 20% at 6% oxygen concentration within 240 minutes and 0% at 7% of oxygen concentration rate. In conclusion, we found out through oxygen concentration rate test that the Concentration of deaths was 5 to 6%. Also LC50(rat, 4hr) of Dose-Response concentration was calculated to be 5.5%.
