Week 1 Flashcards
Define environmental toxicology
branch of tox that studies the effects of the exp of humans & other living things to chem’s in the environment
Define Ecotoxicology
branch of toxicology that studies the effects of the exposure of living organisms to chem’s in the environment
Risk = _____ + _____
Risk = Toxicity + Exposure
What is risk mitigation?
actions taken to reduce the potential of risk, i.e. harm
Definition: any physical, chemical, biological, or radiological substance or matter that has an adverse effect on air, water, soil (or biota)
Contaminant
Definition: generally, any substance introduced into the environment that adversely affects the usefulness of a resource
Pollutant
Definition: Harmful to living organisms
Toxic
Definition: a chemical or mixture that may present an unreasonable risk of injury to health or the environment
Toxic Substance
Definition: Materials contaminating the environment that cause death, injury, disease, and/or birth defects in organisms that ingest or absorb them. The quantities and length of exposure necessary to cause these effects can vary widely
Toxic Pollutants
Definition: The degree of danger posed by a substance to animal or plant life
Toxicity
What are the “big 3” chronic effects?
Survival, growth, and reproduction
Definition: severity of the effect is a fxn of the exposure (ie: dose or [ ]). Bigger dose = more severe effect. Threshold present.
(_______ effects)
Deterministic effects
Definition: Probabilistic in nature. The likelihood, but not necessarily the severity of the effect is a fxn of the exposure (ie, dose or [ ]). Bigger dose = more likely an effect will occur. No threshold.
(_______ Effects)
Stochastic effects
These types of effects usually start at 96 hours or less; msrd effect usually death or lethality or mortality or survival (lack thereof)
Acute/short-term effects
These types of effects usually have lifetime exposure and a variety of effects
Chronic/long-term effects
What is the diff b/w endpoint and effect?
Effect is the harmful, adverse effect you are LOOKING FOR
Endpoint is how much of it you want to MEASURE
What are LC and LC50?
LC = lethal concentration
LC50 = [ ] lethal to 50% of the exposed population
What are EC and EC50?
EC = Effects [ ]
EC50 = [ ] that produces the desired effect in 50% of the exposed pop’n
What are LD and LD50?
LD = Lethal Dose
LD50 = Dose that is lethal to 50% of exposed pop’n
What is the diff b/w a dose and a [ ] and what are the units?
[ ] = exposed in ambient environment (mg/L or mg/kg)
Dose - qty of a toxicant delivered inside the organism (mg/kg body weight)
What do these acronyms stand for?
LEL, NEL, LOEL/LOEC, NOEL/NOEC, LOAEL, NOAEL, MATC
LEL - Lowest effects level
NEL - No effects level
LOEL/LOEC - lowest observed effects level OR [ ]
NOEL - No Observed Effects Level OR [ ]
LOAEL - Lowest observed adverse effects level
No observed adverse effects level
MATC - Maximum acceptable toxicant concentration
How do you determine the MATC?
Geometric mean of the LOEC and NOEC (times them together & take the square root)
What must be specified in order for the LC50 to have any meaning?
Duration of exposure must be specified
What are 2 major classes of exposures?
Acute and chronic
