AP Environmental Science · Unit 8 Aquatic/Terrestrial Pollution
Learning Objectives
LD50: Lethal Dose 50%. The exact dosage of a chemical that kills precisely 50% of the test population in a given time.
The Curve: Plots Dose (mg/kg) on the X-axis against Mortality (%) on the Y-axis. Usually forms an S-curve.
Threshold: The maximum dose where NO observable toxic effect occurs. Any dose above this starts causing mortality.
Tags
ToxicologyLD50Dose-ResponsePollution
MORTALITY (%)
DOSE (mg/kg)
Toxicology Lab Protocol
Experimental Results
Dose (mg/kg)
Pop. Tested
Dead
Mortality (%)
Status: Waiting to initiate acute toxicity test on 6 specimen groups.
AP Exam Tip
A lower LD50 means a substance is MORE toxic. For example, Botulinum toxin has an LD50 of 0.000001 mg/kg. Table salt has an LD50 of 3,000 mg/kg. To find the safe human dose, scientists find the animal LD50 and divide it by 100 or 1000!