how to define envrionmetal risk
the probability of a specific consequence
what if many different types of risk may occur
risk=(probability of consequence)*(size of loss)
2 categories of health risks? (in order of priority)
- risk of contracting cancer
2. all other human ilnesses and diseases
Hazard assessment steps
- determine whether there is a potential problem from chemical
- determine whether exposure can cause illness
what are the 4 steps to risk assessment?
- Hazard assessment
- Dose-response assessment
- Exposure assessment
- Risk characterization
chronic daily intake formula
CDI=average daily dose/body weight
Incremental risk
calculating the risk of getting cancer from a given exposure. multiply the CDI by potency factor
what is the level of acceptable risk?
1 in million to 1 in 10000 or less
what is serious risk?
1/1000 or more
what is the reference dose?
parameter to assess the risk of a non-carcnigenic chemical
reference dose formula?
RfD=NOAEL/(UF*MF)
where UF is the uncertainty factor, MF is the modifying factor, NOAEL is the dosage of chemical below which no adverse health effects are observed
what are the 4 factors which increase the uncertainty factor by factor of 10.
- extrapolating data from animals to humans
- extrapolating data from subchronic substances to chronic ones
- variable responses in the affected population
- lack of data
what is the hazard quotient?
compare the actual estimated daily intake to the reference dose
T/F, any does less than or equal to the RfD does not pose a health concern
T
hazard quotient formula
HQ=ADD/RfD
where ADD is the average daily dose
what are 4 options for dealing with unacceptable risk?
- eliminate or reduce the source
- exposure pathway can be reduced/eliminated
- human exposure can be reduced/eliminated
- effects can be treated/compensated for after they occur
describe the different influence diagrams
- oval: chance events
- rectangle: decisions based on the influence of factors
- rounded corner rectangle: calculations and constant values
- Hexagon:objective (optimization-minimize cost and risk to maximize benefit
