Risk Assessment

Question 1

Hazard Quotient

Answer 1

HG=Exposure (mg/kg-day)/Toxicity Value (mg/kg-day)

HG should be less than one (exposure below toxicity value)

Question 2

Hazard Index

Answer 2

Add up all HQs for chemicals that share same target organ

Should be less than 1.0

Question 3

Probabilistic risk assessment (PRA)

Answer 3

A risk assessment that uses probabilistic methods to derive a distribution of risk or hazard based on multiple sets of values sampled for random variables.

Hayes’ Principles and Methods of Toxicology (p. 2102). CRC Press. Kindle Edition.

Question 4

Risk quotient

Answer 4

risk quotient (RQ) is calculated by dividing a point estimate of exposure by a point estimate of effects

deterministic approach

Question 5

Steps of risk assessment

Answer 5

Hazard ID
dose-response assessment
exposure assessment
risk characterization

Question 6

Acceptable Daily Intake

Answer 6

ADI values may be defined as the daily intake of chemical during an entire lifetime, which appears to be without appreciable risk on the basis of all known facts at that time.

Klaassen, Curtis D.; Watkins, John B.. Casarett & Doull’s Essentials of Toxicology, Third Edition (Lange) . McGraw-Hill Education. Kindle Edition.

Question 7

RfD and ADI calculation

Answer 7

RfDs and ADI values typically are calculated from NOAEL values by dividing by uncertainty (UF) and/or modifying factors (MF):

Klaassen, Curtis D.; Watkins, John B.. Casarett & Doull’s Essentials of Toxicology, Third Edition (Lange) . McGraw-Hill Education. Kindle Edition.

Question 8

Tolerable daily intakes

Answer 8

Tolerable daily intakes (TDIs) can be used to describe intakes for chemicals that are not “acceptable” but are “tolerable” as they are below levels thought to cause adverse health effects.

Klaassen, Curtis D.; Watkins, John B.. Casarett & Doull’s Essentials of Toxicology, Third Edition (Lange) . McGraw-Hill Education. Kindle Edition.

Question 9

virtually safe doses

Answer 9

those corresponding to a 95% upper confidence limit on adverse response rates).

Klaassen, Curtis D.; Watkins, John B.. Casarett & Doull’s Essentials of Toxicology, Third Edition (Lange) . McGraw-Hill Education. Kindle Edition.

Question 10

benchmark dose (BMD) method

Answer 10

the lower confidence bound for a dose at a specified response level (benchmark response [BMR]) is calculated. The BMR is usually specified at 1%, 5%, or 10%. The BMDx (with x representing the percent BMR) is used as an alternative to the NOAEL value for reference dose calculations.

RfD = BMDx/(UF x MF)

Klaassen, Curtis D.; Watkins, John B.. Casarett & Doull’s Essentials of Toxicology, Third Edition (Lange) . McGraw-Hill Education. Kindle Edition.

Question 11

Attributable risk

Answer 11

rate of an even in an exposed population minus the rate in a nonexposed population

Question 12

Relative risk

Answer 12

ratio of the risks for an event for the exposure group to the risks for the non-exposure group

Question 13

Prevalence

Answer 13

proportion of persons in a population who have a particular disease or attribute at a specified point in time or over a specified period of time

Question 14

Prevalence vs Incidence

Answer 14

Prevalence refers to proportion of persons who have a condition at or during a particular time period, whereas incidence refers to the proportion or rate of persons who develop a condition during a particular time period.