risk Flashcards
(24 cards)
how many synthetic chemicals are in use in industry? how many have been tested for carcinogens?
70,000 in use, 1,600 tested for carcinogens
What is risk and environmental risk?
risk is the likelihood of injury, disease or death
environmental risk - risk resulting from exposure to a potential environmental hazard
as hazards approach infinite, risk can be reduced to near zero by reducing exposure to near zero
as hazards approach zero, risk is not severely impacted
what attributes elevate perception of a risk?
if the risk is:
involuntary
uncontrollable
inequitable
unknown
leaves a permanent effect
what attributes lower the perception of a risk?
if the risk is:
voluntary (the person chooses the risk i.e. smoking)
controllable
equitable
known
temporary effect
What is risk assessment by definition?
Finding out if some contaminant will affect peoples healths and the environment
the process of estimating the probability of occurrence of an adverse effect on human and ecological health resulting from contaminant exposure.
the systematic process of identifying and evaluating substances, persons potentially affected, and exposure to the substances in order to estimate cancer risks or hazard indices
what are the three main components that must exist for something to be a risk?
contaminants
receptors
exposure pathways
all three must be present for there to be a risk
how are contaminants evaluated in risk assessment?
if a chemical concentration exceeds the selected standard then the contaminant is considered a contaminant of concern
what are some examples of exposure pathways considered in risk assessment?
air
groundwater/surface water
sediment
soil
what are receptors in risk assessment?
on-site receptors: humans (workers, residential, recreational users, trespassers)
off-site receptors: humans (workers, residential, recreational users, trespassers)
ecological receptors: plants, mammals, soil invertebrates aquatic organisms
what is the risk assessment process>
two simultaneous pathways ending in the same step
Hazard Assessment (what are we considering?) –> toxicity assessment/dose response (how bad is it)–>risk characterization (what is the risk?)
exposure assessment (how much/how extensive is it?) –>risk characterization (what is the risk?)
what happens during exposure assessment in risk assessment?
-degree of exposure is confirmed from seeing how much chemical is present, who/what is exposed to it and how they are exposed to it
-an estimate of the dose of contaminants is made
what happens during hazard identification in risk assessment?
What is there and how much?
-find out what has happened at and around the site of contaminant exposure
-find where contaminants are located
-find out what receptors there are and why they are there
-review and analyze toxicity data to find evidence linking health effects
-collect samples of soil, water, air, fish
what is the toxicity assessment in risk assessment?
-“the dose makes the poison”
-find out at what dose is harm caused
-toxicity reference values are determined
what is risk characterization in risk assessment?
Find out what the chemical is
Find out what the health risks are
Find out how sure we are about the risk estimates
what are toxicants and how do they effect humans?
a toxicant is any toxic substance
they enter humans through:
ingestion
inhalation
eye or dermal contact
these toxicants are either stored or eliminated in the body (bioaccumulation/biomagnification, stored mostly in fat cells)
what is acute toxicity?
the ability of a substance to cause severe biological harm or death soon after single exposure or dose
any poisonous effect resulting from a single short-term exposure to a toxic substance
what is acute toxicity and how is it defined?
toxicity is considered acute depending on how likely it is to cause death
LD50 is a measure of toxicity where at this lethal dose 50% of the population would die
what is mutagenisis?
Anything that causes mutations in human or non-human genes
genotoxicity: chemical or other agent that damages cellular dna resulting in mutations or cancer
mutations: a gene mutation is a permanent change in DNA
carcinogens: cancel causing substance
teratogens: substance that causes birth defects
what is the dose-response assessment?
a chronic toxicity assessment that finds mathematical relationship between the amount of toxicant a human is exposed to and the resulting health effects
how do we define which substances are considered carcinogenic or not?
non-carcinogenic substances have no consequences to brief or low exposures
carcinogenic substances are those that pose risk upon repeated exposure
what is the potency factor for carcinogens?
potency or slope factor is used in risk assessment to estimate a lifetime probability of an individual developing cancer due to exposure to a carcinogen
what is the NOAEL? LOAEL? RfD?
No Observable Adverse Effect Level
Lowest Observable Adverse Effect Level
Reference Dose (acceptable daily intake)
What does the HQ represent?
The Hazard Quotient represents the quantification of risk of exposure to non-carcinogenic substances
