Human lethality estimation Subject

Health experts advise that moderated amounts of caffeine from 100 to 300 mg per day are acceptable. Adult Americans consume approximately 250 mg of caffeine per day. The LDJ0 (the lethal dose that kills 50% of a test population of individuals subjected to a substance) of caffeine for humans is estimated between 150 and 200 mg per kilogram of body weight. The amount of caffeine in some popular food items is given in Table 18.1. 

Human toxicity data, especially the median lethal dose, is extrapolated from animals or from accidental poisoning, homicides and suicides. Extrapolations from animal data are educated estimates which consider the differences in species and building in a safety factor. If a lethal dose is 10 mg/kg in a rat and we consider a human to be 10 times more sensitive 1 mg/kg will have another 10-fold safety margin. Animal testing also involves using what may seem as ridiculous doses in order to cover the safety factor. To find a statistically valid effect which occurs once in one million subjects, several million animals would have to be used, which is exhorbitantly... 

N-Pentane (CgHij) is a flammable gas with a molecular weight of 72.17. ACGIH lists the threshold limit values for airborne concentrations at 600 ppm, or 1800 mg/m NIOSH lists the lowest lethal concentration at an estimated 130,000 ppm for an inhalation exposure to a human subject. 

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