Exam 10: Risk and Exposure Assessment

Typically, when assessing cancer effects, researchers assume that there is no threshold no level below which no cancer occurs) while when assessing non-cancer effects, researchers assume that a threshold does exist.

An example of a contact rate, the amount of contact between a person and the medium that contains the agent, is the inhalation rate, the amount of air breathed per unit time.

In which phase of a risk assessment would a researcher investigate the physical and chemical properties of a potential hazard and perhaps perform testing on laboratory animals?

Using the formula: Dose = Exposure x Contact rate Calculate the dose of nitrogen oxide a person would receive if she was breathing at a rate of 1.2 m³/hr and was surrounded by air containing 10 mg/m³ of nitrogen oxide for half an hour.

Which of the following is an example of an indirect method of exposure assessment?

If the hazard index calculated for a given agent is less than 1, it means that public health is at risk and exposure levels must be reduced to protect human health. Hazard Index = Exposure dose / Reference dose)

The purpose of a risk assessment is to collect as much information as possible about a potential hazard and identify the mechanisms that are most likely to cause harm, then use that information to make decisions to protect human health.

If an agent interacts with another agent and its effects are reduced or counteracted, the relationship between these agents would be called:

The results of a dose-response assessment often are plotted on a graph with the exposure level dose) on the x axis and the percent of the population experiencing an effect on the y axis. This graph usually looks like an S-shaped curve. At what point along the curve would you find the No Observed Adverse Effect Level NOAEL)?

What is the term used to refer to the sequence of processes and events that lead from a source to an exposure, for example, the process involved in mercury traveling from power plants to fish to humans?

For many agents, exposure can occur through multiple routes, such as inhalation and ingestion. When calculating total exposure, the exposure of the agent through all possible routes should be considered.

In order to test whether a potential hazard causes chronic toxicity, you would give a laboratory animal a single, high dose of the agent and determine whether it was lethal.

The is the maximum acceptable daily exposure level for humans to a particular agent.

Which of the following equations is the correct way to calculate risk?

What are the steps of a risk assessment?

When risk is calculated quantitatively from a risk assessment, it is best to use the estimate of risk in comparison to the risk estimates calculated for other potential hazards rather than as an independent number.

If the LD₅₀ lethal dose for 50% of the population) is 100 mg/kg for Compound A and the LD₅₀ is 10 mg/kg for Compound B, we know that Compound A is more toxic.

When extrapolating data from animal models to humans, a safety factor frequently is added to a toxicity threshold measures to account for any biochemical or other differences between the species.

The two organs involved in the elimination of toxic or foreign substances are the heart and the lungs.

In which phase of a risk assessment would a researcher investigate the effect of different doses of a potential hazard on the risk of the outcome?