Chapter 17. Human Health and Environmental Risks. Warm-Up. What are the leading causes of death worldwide? How is the economic development of a country related to disease? Rank the following in order of highest probability of death to lowest probability: Airplane accident Drowning
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Human Health and Environmental Risks
(1 in 5,051)
(1 in 1,008)
(1 in 84)
(1 in 5)
(1 in 314)
Epidemiology: field of science that seeks to understand the causes of illness and disease
Retrospective and prospective studies allow researchers to determine the effects of chemicals on individuals
Dose: the amount of a substance that a person has in their body
“The dose makes the poison”
LD50 = 5.3
20 mg/kg ÷ 1000 = 0.02 mg/kg
80 kg × 0.02 mg/kg = 1.6 mg
ED50: effective dose that causes 50% of the individuals to display the harmful, but nonlethal, effect
These effects that change the behavior of the individuals or cause harm are called sublethal effects
The LD50 and ED50 values for mice are often divided by 1,000 to determine the safe value for humans
Solubility: what can the chemical dissolve in?
Which do you think is generally “better” for the health of an organism?
Water is “better” since it can be diluted
Fats aren’t good since chemicals can gather in body fat of animals
If the element Strogenium has an LD50 of 40 mg/kg, how big of a dose is necessary to kill a 30 kg goat?
Probability of being exposed to a hazard
Probability of being harmed if exposed