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
What are two acute effects?
death and immobilization
Chemical A has an LC50 of 5mg/L and chemical B has an LC50 of 16mg/L. Which is more toxic?
Chemical A
Which would result from an aquatic toxicity test with fish, a LOEL or a LOEC?
LOEC ???
What 3 endpoints are statistically derived?
LC50, E50, and LD50
What 3 factors are needed to describe exposure?
Duration, Magnitude, and Frequency
What aspect of uptakes of pollutants requires ENERGY?
Active Transport
What type of molecules can move through membranes by diffusion?
Neutral, lipophilic
What type of organic compounds are usually lipophilic? Polar or non-polar?
Non-polar
Which compound will pass through a membrane more easily; Compound A with a low Log Kow or compound B with a high Log Kow??
B
What is significant about Xenobiotic molecules in regards to membranes?
They move through membrane pores
Toxicity in sediments is affected by: (4)
Grain size, organic carbon content, acid volatile sulfides, and oxygen
Name the Toxicity effects and give examples of toxins:
A. 1+1=0.5
B. 1+1=2
C. 1+1=5
A. Antagonistic: Cadmium + Zinc
B. Additive: PAHs
C. Synergistic: Copper Sulfate and Diquat
What do these 3 acronyms stand for?
BTEX
PAHs
PCBs
BTEX = Benzene, Toluene, Ethylbenzene, and Xylene
PAHs = Polycyclic Aromatic Hydrocarbons
PCBs = Polychlorinated biphenyls
