Studies in Relation to LD50
Name one importance of having LD50 studies done.
Some variation of the following:
- Provides aid in times of an emergency where organisms are exposed to substances
- Provides insight on the affects of toxicity in relation to humans exposed to substances
Provide a concise summary of what LD50 is.
LD50 is a study. It determines the dose of a substance (taken by a population) that would be enough to kill 50% of that population of a species.
What animals are LD50's most commonly experimented on?
Lab rats and lab mice
LD50 testing is ethically unproblematic and widely accepted for all substances.
False. (Ethical concerns regarding animal testing are significant.)
On what scale is toxicity measured in? Which number represents the least toxicity and which number represents the most toxicity?
What is the least toxic substance and one of the most toxic substances that were discussed in class? (Specify which is which)
Water is the least toxic substance. One of the most toxic substances is cyanide.
What is a non-fatal effect that a substance has on an organism — meaning the organism doesn’t die, but it still experiences harm or changes in function or behavior? (HINT: It's not "Lethal", it's..)
Sub-Lethal
A high LD50 value automatically means a substance is safe for human use.
False (Other factors like long-term effects and bio-accumulation need consideration.)
What is another name for LD50 studies?
Dose Response Studies
Through what two processes do toxins end up digested by an organism?
Bioaccumulation and Biomagnification
What is the highest experimental point (dose or exposure level) at which no effects are observed in a study?
No Observed Effect Level (NOEL)
The LD50 value is highly dependent on the species being tested. Metabolic rates, physiological differences, and other factors mean that the lethal dose for one species will not be the same for another
True
What are the names for types of experiments that expose organisms to hazardous substances for a short and a long period of time? (Specify which is which)
What is LD50 most commonly measured with? (____ per ____)
Miligrams per kilograms
What is the lowest dose of a substance at which a measurable effect first appears in the test subject?
Threshold Dose
The LD50 value alone provides a complete picture of the risks associated with exposure to a substance.
False (It ignores factors like synergistic effects with other chemicals, chronic exposure effects, and non-lethal health impacts.)
What is the process of converting lethal dose data from a study conducted on lab animals to relevant data for humans?
Extrapolation OR Generalization
Who is the person who originally came up with the idea of LD50 studies?
J.W Trevan
What is a graph that shows how a biological system responds to different doses of a substance?
Dose Response Curve
The development of alternative toxicity testing methods is driven solely by ethical concerns about animal welfare.
False. (While ethical concerns are significant, the drive for alternatives is also fueled by the limitations of LD50 testing, including its failure to accurately predict chronic effects, its inability to assess impacts on entire ecosystems, and the high costs of animal testing.)