Risk Assessment Vocabulary

Question 1

Additional Risk

Answer 1

Additional proportion of total animals (or humans) that respond given a particular set of conditions (e.g., exposure does and route of exposure)

Question 2

ADI

Answer 2

“Allowable Daily Intake” The amount of a chemical to which a person can be exposed on a daily basis over an extended period of time (usually a lifetime) without suffering an adverse effect. Sometimes referred to as “Tolerable Daily Intake” (TDI)

Question 3

Adverse

Answer 3

Contrary to one’s interest or welfare hostile, unfavorable, afflicting

Question 4

Adverse Effect

Answer 4

Biochemical change, functional impairment, or pathological lesion that may affect the performance of the whole organism or that reduce an organism’s ability to respond to an additional challenge

Question 5

Benchmark Dose

Answer 5

An exposure level that corresponds to a statistical lower confidence limit (“lower bound”) on the dose producing a predetermined response. That predetermined response is the “Benchmark Response”

Question 6

Bright Line

Answer 6

Specific numerical value meant to provide a practical distinction between acceptable and unacceptable levels of risk

Question 7

Central Tendency

Answer 7

The mean (average) or the median (midpoint) of a range of relevant risk estimates for a particular situation, exposure, or chemical hazard

Question 8

Cancer Potency Factor

Answer 8

Excess risk per unit of dose at a specific dose (a.k.a. risk factor) which for cancer is more than one in a million

Question 9

Critical Effect

Answer 9

The first adverse effect, or its known precursor, that occurs as the dose rate increase; the adverse effect that occurs at the lowest exposure level (and is therefore the basis for exposure limits). Also known as “Critical Endpoint”

Question 10

Effect

Answer 10

Response to a stimulus, result or outcome

Question 11

Excess Risk

Answer 11

The proportion of animals (or humans) that respond when a given a particular set of conditions (e.g., exposure does and route of exposure) that would otherwise not respond. a.k.a. Extra Risk

Question 12

Extra Risk

Answer 12

The proportion of animals (or humans) that respond when a given a particular set of conditions (e.g., exposure does and route of exposure) that would otherwise not respond. a.k.a. Excess Risk

Question 13

Extrapolation

Answer 13

Estimation of response outside the range of experimental data OR the estimation of response in a different species or by a different exposure route than that used to generate the experimental data

Question 14

Hazard Quotient

Answer 14

The ratio of the dose resulting from exposure to an agent and the chemical’s reference dose (RfD) or other screening benchmark

Question 15

Health

Answer 15

State of an organism with respect to functioning, disease, and abnormality at any given time; optimal functioning with freedom from disease and abnormality

Question 16

Health Effect

Answer 16

Functional or structural response affecting the organism, but not necessarily leading to impairment or reduced capacity

Question 17

Interpolation

Answer 17

Estimation of responses within the range of experimental data; determination of intermediate values in a series on the basis of observed values

Question 18

LOAEL

Answer 18

“Lowest Observed Adverse Effect Level” Lowest experimentally determined dose that causes statistically or biologically significant adverse effects beyond those seen in a control group

Question 19

LOEL

Answer 19

“Lowest Observed Effect Level” Lowest experimentally determined dose that causes a statistically or biologically significant effect beyond those seen in a control group

Question 20

MOE

Answer 20

“Margin of Exposure” The ratio of the NOAEL to the estimated exposure does; also the ratio of the Point of Departure to the estimated exposure dose.
` MOE indicates how close an estimated exposure comes to the NOAEL or the Point of Departure

Question 21

MOS

Answer 21

Margin of Safety - older term for MOE

- ratio indicates how close an estimated exposure comes to the NOAEL or the Point of Departure

Question 22

Mechanism of Action

Answer 22

Specific details of the biological processes (e.g., at the molecular level) by which an agent causes its effects

Question 23

Mode of Action

Answer 23

Series of key events involving interaction with cells, leading to operation or anatomic changes, resulting in disease; an incomplete aspect of the Mechanism of Action.

Question 24

NOAEL

Answer 24

“No Observed Adverse Effect Level” An experimentally determined dose at which no statistically or biologically significant indications of toxic effects are observed beyond those seen in a control group.

Question 25

NOEL

Answer 25

“No Observed Effect Level” Highest experimentally determined dose at which no statistically or biologically significant effects are observed beyond those seen in a control group

Question 26

Pharmacodynamics

Answer 26

The study through measurement or modeling of the response of a biological system as a function of dose. Referred to as: “The linkage between dose and respond”

Question 27

Pharmacokinetics

Answer 27

The study through measurement or modeling of the absorption, distribution, metabolism, and excretion of drugs or chemicals in a biological system as a function of time. Referred to as: “The linkage between exposure and dose:

Question 28

Point of Departure

Answer 28

The dose-response point that marks the beginning of a low-dose extrapolation. This point can be the lower bound on a dose for an estimated incidence or a change in respond level from a dose-respone model (BMD), or a NOAEL or LOAEL for an observed incidence, or change in level of response.

Question 29

Potency Factor

Answer 29

Excess risk per unit of dose at a specific dose

-a.k.a. Potency Factor/ Slope Factor

Question 30

Q1*

Answer 30

The upper bound on the cancer potency factor for low-dose exposures as calculated using the linearized multistage (LMS) model

Question 31

Residual Risk

Answer 31

That risk which remains after risk reduction actions have been implemented

Question 32

RfC

Answer 32

"Reference Concentration"  
An estimate (with uncertainty spanning perhaps an order of magnitude) of a continuous inhalation exposure to the human population (including sensitive subgroups) that is likely to be without appreciable risk of adverse effects during a lifetime.

Question 33

RfD

Answer 33

"Reference Dose"
An estimate (with uncertainty spanning perhaps an order of magnitude) of a daily exposure to the human population (including sensitive subgroups) that is likely to be without appreciable risk of adverse effects during a lifetime

Question 34

Risk

Answer 34

Probability of specific, generally adverse outcome (e.g., injury, disease or death) given a particular set of conditions (e.g., exposure dose and route of exposure) and relative to the background probability.

Question 35

Risk Assessment

Answer 35

Scientific activity of evaluating the toxic properties of a chemical and the conditions of human exposure to it in order to ascertain the likelihood that exposed humasn will be adversely affected and to characterize the nature of the effects they may experince

Question 36

Risk Factor

Answer 36

Excess risk per unit of dose at a specific dose.

a.k.a. Slope Factor/ Potency Factor

Question 37

Risk Management

Answer 37

The process of analyzing, selecting implementing and evaluating alternative actions to reduce risk

Question 38

Screening Benchmark

Answer 38

In ecological risk assessments, the exposure level at or below which the contaminant is not likely to cause adverse effects; generally a NOAEL

Question 39

Slope Factor

Answer 39

Excess risk per unit of dose at a specific dose.

a.k.a. Risk Factor/ Potency Factor

Question 40

Susceptibility

Answer 40

Increased likelihood of an adverse effect, often discussed in terms of a relationship to a factor that can be used to describe a human subpopulation (e.g., life stage, demographic feature, or genetic characteristic)

Question 41

Threshold

Answer 41

Level of exposure above which adverse health effects occur, and below which no such adverse effects occur (or are not expected to occur)

Question 42

Ultimate Toxicant

Answer 42

Form of a toxicant that actually interacts with cellular constituents and elicits toxicity

Question 43

Unit Risk

Answer 43

The upper bound on excess risk at a standardized unit of exposure, usually an exposure level of 1µg/L for drinking water or 1µg/m3 for inhalation

Question 44

Upper Bound

Answer 44

Upper confidence limit of a range of relevant risk estimates for particular situation, exposure, or chemical hazard