Intro to Toxicity Testing

An individual from a population is classified as a

responder or nonresponder

define binomial data

follows a normal distribution because of differences in susceptibility to chemicals among individuals

Steps in toxicity testing

1. Select an organism and chemical combination

2. Introduce the organisms to different levels of chemical

3. Run the test for a set amount of time

4. "score" the test by enumerating affected organisms at each level

5. Statistically determine the toxicity of the chemical

define dose response

is the relationship between the amount of a substance—the dose—and the resulting effect on a living organism.

define effective dose

results in desired (therapeautic) effect

• analgesia, intoxicatoin, anesthesia

define toxic dose

results in injury

• liver/kidney damage, neurological disorders

define lethal dose

results in death

• whole organism level of effect

define threshold dose

the lowest dose that elicits a response that is significantly greater than zero

define hormesis

certain non-essential substances can have beneficial health effects in small amounts toxic effects at higher amounts