Eviro. Unit 5 Lesson 8

Describe the type of substance that bioaccumulates better in ecosystems.

Fat-soluble toxins are stored in body tissues and they bioaccumulate and magnify through ecosystems.

Lethal doses and median lethal doses are most often determined in laboratory experiments using animals, usually mice or rats.

Laboratory experiments

These studies take a population, such as a town, which has been exposed to a certain chemical and compare it to a group of people, such as a neighboring town, which has not been exposed to the chemical.

Population studies

Which type of chemicals can be found surrounding a cell?

Water-soluble toxins get into the solutions that surround our cells.

Dose-responsive curve

a graph that shows the relationship between the dose and the effect of that dose on the organism

What might be contributing to the rise of certain diseases such as autism and childhood cancers?

exposure to trace amounts of thousands of different chemicals

LD50 refers to a substance's _____.

median lethal dose

Dose

the amount of a chemical that a person ingests, inhales, or absorbs through the skin

Median lethal dose

the amount of toxin that kills 50% of the animals in a specified time period

Lethal dose

the amount of toxin that will kill an animal

Toxicity

the measure of how harmful a substance is

toxicology

the study of poisonous substances

What are three reasons that animal rights groups oppose testing on animals?

-There are other ways to determine toxicity, such as computer simulations or using individual animal cells. -Animals and humans differ enough that the data from the tests is not reliable. -Animals feel pain, so it is unethical.

Why do we know so little about the effect of chemicals?

-Toxicity levels might vary widely between individuals. -Humans are not exposed to one chemical at a time. -It's even more difficult and expensive to see how they work in the real world on humans instead of in a lab on rats. -It's very difficult and expensive to determine the toxicity of chemicals in a laboratory setting.

Select the three different ways to determine a substance's toxicity

-population studies -laboratory experiments -case reports

What four factors influence a chemical's toxicity.

-solubility of the toxin -persistence of chemical in environment -genetics -the age of the person

Case reports include data of individuals suffering harm or injury after exposure to a chemical or pathogen.

Case reports

The ____ makes the poison.

dose