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Lethal Dose. Toxicity. Chem Catalyst. Which substance do you think is most toxic? Alcohol (ethanol, C 2 H 6 O 3 ) Aspirin (salicylic acid, C 7 H 6 O 3 ) Arsenic (III) oxide (As 2 O 3 ). Lethal Dose.
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Lethal Dose • Toxicity
Chem Catalyst • Which substance do you think is most toxic? • Alcohol (ethanol, C2H6O3) • Aspirin (salicylic acid, C7H6O3) • Arsenic (III) oxide (As2O3)
Lethal Dose • Lethal Dose: LD50 is the amount of an ingested substance that kills 50% of a test sample of an animal (usually lab rats)
Converting LD50 • But how do we translate the lethal dose for a lab rat to the lethal dose for a human?? • Using the rat data, scientists translate this to a lethal dose per kilogram of body weight. ?
Let’s Try: Aspirin • If the LD50 for aspirin is 200mg/kg, based on testing with lab rats, what is the calculated lethal dose for a 132 lb. (60 kg) adult? • Answer: 12,000 mg.
Alcohol • If the LD50 for alcohol is 7,060 mg/kg in rats, what is the calculated lethal dose for a 60 kg adult? • Answer: 423,600 mg
Alcohol Poisoning • About 50,000 cases of alcohol poisoning are reported per year in the US. • An estimated 4,000 of those cases resulted in death.
Arsenic • If the LD50 of arsenic is 15mg/kg in rag, what is the calculated lethal dose for our 60 kg person? • Answer: 900 mg.
Different toxic substances have different lethal doses • Aspirin: 12,000 mg • Alcohol: 423,600 mg • Arsenic: 900 mg