Jump to main content or area navigation.

Contact Us

Water: Microbial

Thesaurus of Terms Used in Microbial Risk Assessment - 5.5  Exposure Terms

Go to Thesaurus Contents
Go to Thesaurus Index

absorbed dose
  1. The amount of a substance penetrating across an absorption barrier (the exchange boundaries) of an organism, via either physical or biological processes. Sometimes called internal dose.  (EPA 1992)
  2. The amount crossing a specific absorption barrier (e.g., the exchange boundaries of skin, lung, and digestive tract) through uptake processes.  (EPA 2005b)
  3. The amount of a substance absorbed into the body, usually per unit of time. The most common unit of dose is mg per kg body weight per day (mg/kg-day).  (RAIS 2004, SRA 2004)
    RELATED TERMS: dose
absorption barrier

Any exposure surface that may retard the rate of penetration of an agent into a target.  Examples of absorption barriers are the skin, respiratory tract lining, and gastrointestinal tract wall (see also Exposure surface).  (IPCS 2004)

activity pattern data

Information on human activities used in exposure assessments.  These may include a description of the activity, frequency of activity, duration spent performing the activity, and the microenvironment in which the activity occurs.  (IPCS 2004)

acute exposure
  1. Exposure by the oral, dermal, or inhalation route for 24 hours or less.  (EPA 2003)
  2. One dose (or exposure) or multiple doses (or exposures) occurring within a short time relative to the life of a person or other organism (e.g., approximately 24 hours or less for humans).  (EPA 2004)
  3. A single exposure to a toxic substance that results in severe biological harm or death.  Acute exposures are usually characterized as lasting no longer than a day, as compared to longer, continuing exposure over a period of time.  (EPA 2005b, RAIS 2004)
  4. Contact with a substance that occurs once or for only a short time (up to 14 days).  (ATSDR 2004)
  5. A contact between an agent and a target occurring over a short time, generally less than a day.  (Other terms, such as “short-term exposure” and “single dose,” are also used.)  (IPCS 2004)
    RELATED TERMS: contrast with chronic exposure

Top of Page

acute exposure limits

A variety of short-term exposure limits to hazardous substances, designed to be protective of human health.  Published by different organizations, each limit has a different purpose and definition.  (EPA 2004)

acute toxicity
  1. Any poisonous effect produced within a short period of time following an exposure, usually 24 to 96 hours.  (EPA 2003)
  2. The ability of a substance to cause severe biological harm or death soon after a single exposure or dose. Also, any poisonous effect resulting from a single short-term exposure to a toxic substance.  (EPA 2005b)
  3. Adverse effects that result from a single dose or single exposure of a chemical; any poisonous effect produced within a short period of time, usually less than 96 hours. This term normally is used to describe effects in experimental animals.  (EPA 2005e)

Adverse effects occurring within a short time (usually up to 14 days) after administration of a single dose of test substance, or after multiple doses administered within 24 hours.  (ILSI 2001)
RELATED TERMS: contrast with chronic toxicity

adjusted exposure concentration

An estimate of exposure concentration that has been refined, usually by application of an exposure model, to better understand how people in a particular location interact with contaminated media.  (EPA 2004)
RELATED TERMS: refined exposure concentration

administered dose
  1. The amount of a substance received by a test subject (human or animal) in determining dose-response relationships, especially through ingestion or inhalation.  (EPA 2004)
  2. In exposure assessment, the amount of a substance given to a test subject (human or animal) to determine dose-response relationships.  Since exposure to chemicals is usually inadvertent, this quantity is often called potential dose.  (EPA 2005b)

The method of administration (e.g., dermal, injection, inhalation, ingestion) is also an important aspect of administered dose.

adsorption

Removal of a pollutant from air or water by collecting the pollutant on the surface of a solid material; e.g., an advanced method of treating waste in which activated carbon removes organic matter from waste-water (EPA 2005b)
Noet: Adsorption is different from absorption. Adsorption often means the physical attachement or adhesion of one substance to the surface of another substance.Microbial adsorption to particulate materials in water may be observed and this can affect the fate and transport of the microbial entities.

aerosol
  1. A suspension of liquid or solid particles in air.  (EPA 2003)
  2. Small droplets or particles suspended in the atmosphere, typically containing sulfur.  They are usually emitted naturally (e.g. in volcanic eruptions) and as the result of anthropogenic (human) activities such as burning fossil fuels.  (EPA 2005b)
  3. A fine mist or spray that contains minute particles and may contain microorganisms.  (Queensland Health 2005)

System in which the dispersion medium is a gas and the dispersed phase (composed of solid particles or liquid droplet) does not settle out under the influence of gravity.  (SRA 2004)
RELATED TERMS: bioaerosol

Top of Page

aggregate exposure
  1. The sum of exposures to pesticide chemical residues with a common mechanism of toxicity from multiple sources and multiple routes of exposure.  (EPA 1997a)
  2. The combined exposure of an individual (or defined population) to a specific agent or stressor via relevant routes, pathways, and sources.  (EPA 2004)
  3. The sum total of all exposure to pesticides through inhalation, or dermal, oral, or optic contact.  (EPA 2005e)
ambient level

The level (of pollutant) in the general environment as characterized by an average over a suitably long time and large volume.  (RAIS 2004, SRA 2004)

ambient measurement

A measurement of the concentration of a substance or pollutant within the immediate environs of an organism; taken to relate it to the amount of possible exposure.  (EPA 2005b)

applied dose

The amount of a substance in contact with an absorption boundary of an organism (e.g., skin, lung, gastrointestinal tract) and is available for absorption.  (EPA 2004)
RELATED TERMS: dose

average daily dose          (ACRONYM: ADD)
  1. Dose that is averaged over a specified time period taking into account the frequency, duration, and intensity of exposure during that time period.  ADDs are usually expressed in units of mg/kg/day.  (EPA 1998a)
  2. Dose rate averaged over a pathway-specific period of exposure expressed as a daily dose on a per-unit-body-weight basis.  The ADD is usually expressed in terms of mg/kg-day or other mass-time units.  (EPA 2003)
averaging time

The time period over which something is averaged (e.g., exposure, measured concentration).  (EPA 2004)

bioaccumulation
  1. The net accumulation of a substance by an organism as a result of uptake from and or all routes of exposure (e.g., ingestion of food, intake of drinking water, direct contact, or inhalation).  (EPA 2004)
  2. A process where chemicals are retained in fatty body tissue and increase in concentration over time. (EPA 2005e)

The process whereby certain toxic substances collect in living tissues, thus posing a substantial hazard to human health or the environment.  (RAIS 2004, SRA 2004)
RELATED TERMS: bioconcentration, biomagnification

bioaccumulation factor          (ACRONYM: BAF)

The concentration of a substance in tissue of an organism divided by its concentration in an environmental medium in situations where the organism and its food are exposed (i.e., accounting for food chain exposure as well as direct chemical uptake).  (EPA 1999a)

Top of Page

bioaerosol

Organisms or biological agents that can be dispersed through the air and that have the potential to affect human health (NSWEPA 2004)
RELATED TERMS: aerosol, airborne transmission

bioconcentration

  1. The net accumulation of a substance by an organism as a result of uptake directly from an environmental medium (e.g., net accumulation by an aquatic organism as a result of uptake directly from ambient water, through gill membranes or other external body surfaces).  (EPA 2004)
  2. The tendency of a chemical to accumulate in a living organism to levels in excess of the concentration in its surrounding environment.  (AIHA 2000)
bioconcentration factor          (ACRONYM: BCF)

The concentration of a substance in tissue of an organism divided by the concentration in an environmental medium (e.g., the concentration of a substance in an aquatic organism divided by the concentration in the ambient water, in situations where the organism is exposed through the water only).  (EPA 2004)

biologically effective dose

The amount of chemical that reaches the cells or target site where an adverse effect may occur.  (EPA 2004)

biomagnification (biological magnification)
  1. The process whereby certain substances, such as pesticides or heavy metals, transfer up the food chain and increase in concentration.  For example, a biomagnifying chemical deposited in rivers or lakes absorbs to algae, which are ingested by aquatic organisms, such as small fish, which are in turn eaten by larger fish, eating birds, terrestrial wildlife, or humans.  The chemical tends to accumulate to higher concentration levels with each successive food chain level.  (EPA 2004)
  2. Biomagnification is the increase of tissue accumulation in species higher in the natural food chain as contaminated food species are eaten.  (EPA 2005e)
  3. The concentration of certain substances up a food chain. A very important mechanism in concentrating pesticides and heavy metals in organisms such as fish.  (RAIS 2004, SRA 2004)
chronic exposure
  1. Repeated exposure by the oral, dermal, or inhalation route for more than approximately 10% of the life span in humans (more than approximately 90 days to 2 years in typically used laboratory animal species).  (EPA 2003)
  2. Continuous exposure, or multiple exposures, occurring over an extended period of time or a significant fraction of the animal’s or the individual’s lifetime.  (EPA 2004)
  3. Multiple exposures occurring over an extended period of time or over a significant fraction of an animal’s or human’s lifetime (usually seven years to a lifetime).  (EPA 2005b)
  4. Contact with a substance that occurs over a long time (more than one year).  (ATSDR 2004)
  5. Multiple exposures occurring over an extended period of time, or a significant fraction of the animal’s or the individual’s lifetime.  (RAIS 2004)

A continuous or intermittent long-term contact between an agent and a target.  (Other terms, such as “long-term exposure,” are also used.)  (IPCS 2004)
RELATED TERMS: contrast with acute exposure

Top of Page

cocktail effect

A term commonly used to describe the possible effect on people of being exposed to a mixture of chemical residues, for example of different pesticides.  (FSA 2005)

consumption rate

The average quantity of an item consumed or expended during a given time interval, expressed in quantities by the most appropriate unit of measurement per applicable stated basis.  (EPA 2004)

contact
  1. Exposure to a source of an infection, or a person so exposed.  (CDC 2005)
  2. A person or animal that has been in such association with an infected person or animal or a contaminated environment as to have had opportunity to acquire the infection.  (MERREA 2005)

The touching or apposition of two bodies.  A person who has been exposed to a contagious disease.  (Stedman 2005)
RELATED TERMS: direct contact, indirect contact, primary contact

contact volume

A volume containing the mass of agent that contacts the exposure surface.  (IPCS 2004)

cumulative exposure

The sum of exposures of an organism to a pollutant over a period of time.  (EPA 2005b)

direct contact

A mode of transmission of infection between an infected host and susceptible host.  Direct contact occurs when skin or mucous surfaces touch, as in shaking hands, kissing, and sexual intercourse.  (MERREA 2005)
RELATED TERMS: contact, primary contact; contrast with indirect contact

estimated exposure dose          (ACRONYM: EED)

The measured or calculated dose to which humans are likely to be exposed considering all sources and routes of exposure.  (EPA 2003)

exposed
  1. A group whose members have been exposed to a supposed cause of disease or health state of interest, or possess a characteristic that is a determinant of the health outcome of interest.  (CDC 2005)
  2. In epidemiology, the exposed group (or simply, the exposed) is often used to connote a group whose members have been exposed to a supposed cause of a disease or health state of interest, or possess a characteristic that is a determinant of the health outcome of interest.  (Last 1983)
  3. In epidemiology, the exposed group (or simply, the exposed) is often used to connote a group whose members have been exposed to a supposed cause of a disease or health state of interest or posses a characteristic that is a determinant of the health outcome of interest.  (MERREA 2005)

Top of Page

exposure
  1. The contact or co-occurrence of a stressor with a receptor.  (EPA 1998a)
  2. Contact made between a chemical, physical, or biological agent and the outer boundary of an organism.  Exposure is quantified as the amount of an agent available at the exchange boundaries of the organism (e.g., skin, lungs, gut).  (EPA 2003)
  3. Contact made between a chemical, physical, or biological agent and the outer boundary of an organism.  (EPA 2004)
  4. The amount of radiation or pollutant present in a given environment that represents a potential health threat to living organisms.  (EPA 2005b)
  5. Radiation or pollutants that come into contact with the body and present a potential health threat. The most common routes of exposure are through the skin, mouth, or by inhalation.  (EPA 2005e)
  6. Contact with a substance by swallowing, breathing, or touching the skin or eyes.  Exposure may be short-term (acute exposure), of intermediate duration, or long-term (chronic exposure).  (ATSDR 2004)
  7. Contact of a chemical, physical or biological agent with the outer boundary of an organism, for example inhalation, ingestion, or contact with the skin.  (CRCWQT 2002)
  8. The level of a substance, for example a chemical, that a person or animal may be subjected to intentionally or non-intentionally. People can be exposed to substances through food, water and their environment.  (FSA 2005)
  9. Concentration or amount of a particular agent that reaches a target organism, system or (sub) population in a specific frequency for a defined duration.  (IPCS/OECD 2004)
  10. Concentration or amount of an infectious micro-organism that reaches the target population, or organism usually expressed in numerical terms of substance, concentration, duration, and frequency.  (KIWA 2004)
  11. Contact with a substance by swallowing, breathing, direct contact (such as through the skin, eyes or mucous membranes) or intravenous injection. Exposure may be either short term (acute) or long term (chronic).  (NYS 1998)
  12. Any characteristic or event that might cause or prevent disease.  (NZ 2002)
  13. The time integral of the concentration of a toxicant that is in the immediate vicinity of various ports of entry (such as lung, GI tract, and skin).  (RAIS 2004, SRA 2004)
  14. Contact between an agent and a target.  Contact takes place at an exposure surface over an exposure period.  (IPCS 2004)

Definition #10 considers exposure in both harmful and beneficial contexts, whereas all the other definitions either state or imply that exposure refers to harmful agents only.  Definition #7 specifically includes duration of the contact. Although not specifically stated in most of the other definitions, the importance of duration can be implied.  In several of the definitions the concentration or dose of the hazard is included.    

exposure analysis

The process of characterizing the source and temporal nature of human exposure to a pathogenic microorganism.  (ILSI 2000)
RELATED TERMS: exposure assessment

Top of Page

exposure assessment
  1. The determination or estimation (qualitative or quantitative) of the magnitude, frequency, or duration, and route or exposure.  (EPA 1997a)
  2. An identification and evaluation of a population exposed to a toxic agent, describing its composition and size, as well as the type, magnitude, frequency, route, and duration of exposure.  (EPA 2003, 2004)
  3. Identifying the pathways by which toxicants may reach individuals, estimating how much of a chemical an individual is likely to be exposed to, and estimating the number likely to be exposed.  (EPA 2005b)
  4. The process of finding out how people come into contact with a hazardous substance, how often and for how long they are in contact with the substance, and how much of the substance they are in contact with.  (ATSDR 2004)
  5. The qualitative and/or quantitative evaluation of the likely intake of biological, chemical, and physical agents via food as well as exposures from other sources if relevant.  (CAC 1999, CAC 2003, FAO/WHO 2003b)
  6. A component of a risk assessment that characterizes the source and magnitude of human exposure to the hazard.  (FDA 2002)
  7. The process of determining or estimating the magnitude, frequency or duration of exposure to a substance such as a chemical.  This may involve taking measurements from many sources to produce an aggregate (combined) assessment.  (FSA 2005)
  8. Evaluation of the exposure of an organism, system or (sub) population to an agent (and its derivatives).  Exposure Assessment is the third step in the process of Risk Assessment.  (IPCS/OECD 2004)
  9. Qualitative and/or quantitative evaluation of the likely intake of microbial hazard via all relevant sources or a specific source.  (KIWA 2004)
  10. The process of measuring or estimating the intensity, frequency, and duration of human exposures to an agent currently present in the environment or of estimating hypothetical exposures that might arise from the release of new chemicals into the environment.  (MERREA 2005, RAIS 2004, SRA 2004)
  11. The process of measuring or estimating the intensity, frequency, and duration of human exposures to an agent currently present in the environment or of estimating hypothetical exposure that might arise from the release of new chemicals into the environment. In its most complete form, it describes the magnitude, duration, schedule, and route of exposures; the size, nature, and classes of the human populations exposed; and the uncertainties in all estimates. Exposure assessment is often used to identify feasible prospective control options and to predict the effects of available control technologies on exposure. (NRC 1983)
  12. A process that estimates the amount of a chemical that enters or comes into contact with people. An exposure assessment also describes the length of time and the nature and size of a population exposed to a chemical.  (NYDOH 1999)
  13. Exposure assessment is the determination of the amount, duration, and frequency of an actual or hypothetical exposure of people, organisms, or the environment to a substance or an activity that can affect health, the environment, or the ecosystem.  Exposure assessments specify the population that might be exposed, identifies the routes through which exposure can occur, and estimates the magnitude, duration, and timing of the doses that people might receive as a result of their exposure.  (NYS 1998)

The process of estimating or measuring the magnitude, frequency, and duration of exposure to an agent, along with the number and characteristics of the population exposed.  Ideally, it describes the sources, pathways, routes, and the uncertainties in the assessment.  (IPCS 2004)
RELATED TERMS: exposure analysis

exposure concentration
  1. The concentration of a chemical in its transport or carrier medium (i.e., an environmental medium or contaminated food) at the point of contact.  (EPA 1997a, EPA 2004)
  2. The concentration of a chemical or other pollutant representing a health threat in a given environment.  (EPA 2005b)
  3. The exposure mass divided by the contact volume or the exposure mass divided by the mass of contact volume, depending on the medium.  (IPCS 2004)

Top of Page

exposure duration
  1. The total time an individual is exposed to the chemical being evaluated or the length of time over which contact with the contaminant lasts.  (EPA 2004)
  2. Toxicologically, there are three categories describing duration of exposure: acute (one-time), subchronic (repeated, for a fraction of a lifetime), and chronic (repeated, for nearly a lifetime).  (REAP 1995)
  3. The length of time over which continuous or intermittent contacts occur between an agent and a target.  For example, if an individual is in contact with an agent for 10 min per day for 300 days over a 1-year time period, the exposure duration is 1 year.  (IPCS 2004)
exposure event

The occurrence of continuous contact between an agent and a target.  (IPCS 2004)

exposure factor

Any of a variety of factors that relate to how an organism interacts with or is otherwise exposed to environmental pollutants (e.g., ingestion rate of contaminated fish).  Such factors are used in the calculation of exposure to toxic chemicals.  (EPA 2004)

exposure investigation

In public health assessment, the collection and analysis of site-specific information and biologic tests (when appropriate) to determine whether people have been exposed to hazardous substances.  (EPA 2004)

exposure loading

The exposure mass divided by the exposure surface area.  For example, a dermal exposure measurement based on a skin wipe sample, expressed as a mass of residue per skin surface area, is an exposure loading.  (IPCS 2004)

exposure mass

The amount of agent present in the contact volume.  For example, the total mass of residue collected with a skin wipe sample over the entire exposure surface is an exposure mass.  (IPCS 2004)

exposure model
  1. A conceptual or mathematical representation of the exposure process.  (IPCS 2004)
  2.  
exposure modeling

The mathematical equations simulating how people interact with chemicals in their environment.  (EPA 2004)

Top of Page

exposure pathway
  1. The course a chemical or physical agent takes from a source to an exposed organism.  An exposure pathway includes a source and release from a source, an exposure point, and an exposure route.  If the exposure point differs from the source, a transport/exposure medium (e.g., air) or media (in cases of intermedia transfer) also is included.  (EPA 2004)
  2. The path from sources of pollutants via soil, water, or food to man and other species or settings.  (EPA 2005b)
  3. pathway of exposure - The physical course a pesticide takes from the source to the organism exposed (e.g., through food or drinking water consumption or residential pesticide uses). (EPA 2005e)
  4. The route a substance takes from its source (where it began) to its end point (where it ends), and how people can come into contact with (or get exposed to) it.  An exposure pathway has five parts: a source of contamination (such as an abandoned business); an environmental media and transport mechanism (such as movement through groundwater); a point of exposure (such as a private well); a route of exposure (eating, drinking, breathing, or touching), and a receptor population (people potentially or actually exposed).  When all five parts are present, the exposure pathway is termed a completed exposure pathway.  (ATSDR 2004)
  5. The process by which an individual is exposed to contaminants or disease organisms that originate from a specified source.  An exposure pathway consists of the following five elements: source of contamination, environmental media and transport mechanisms, point of exposure, route of exposure, and receptor population.  (NYS 1998)
  6. The course an agent takes from the source to the target.  (IPCS 2004)
exposure period

The time of continuous contact between an agent and a target.  (IPCS 2004)

Top of Page

exposure point
  1. An exact location of potential contact between a person and a chemical within an exposure medium. (EPA 1999b)
  2. Location of potential contact between an organism and a chemical or physical agent.  (AIHA 2000)
exposure profile
  1. A summary of the magnitude and spatial and temporal patterns of exposure for the scenarios described in the conceptual model.  (EPA 1998a)
  2. The exposure profile (ecological) identifies the receptors and describes the exposure pathways and intensity and spatial and temporal extent of exposure.  It also describes the impact of variability and uncertainty on exposure estimates and reaches a conclusion about the likelihood that exposure will occur.  The profile may be a written document or a module of a larger process model.  (EPA 2004)
  3. A qualitative and/or quantitative evaluation of the magnitude, frequency, and pattern of exposure to a pathogen, developed during the analysis phase of microbial risk assessment, including a description of the assumptions and uncertainties inherent in such an evaluation.  (ILSI 2000)
exposure-response

Exposure-response has been used by EPA when referring to hazards that are not necessarily pathogens.  For example, exposure to indicator bacteria may be correlated with a response (gastrointestinal illness), but the indicator is not the cause of the response.  Refering to a “dose of indicators” is misleading because it implies the indicator is the causative agent of the health endpoint.
SEE: dose-response

exposure-response relationship

The relationship between exposure level and the incidence of adverse effects.  (EPA 2005b)

exposure route
  1. The way a chemical enters an organism after contact (e.g., by ingestion, inhalation, dermal absorption).  (EPA 1997a, EPA 2004, EPA 2005b)

The way in which an agent enters a target after contact (e.g., by ingestion, inhalation, or dermal absorption).  (IPCS 2004)
RELATED TERMS: route of exposure

exposure scenario
  1. A set of conditions or assumptions about sources, exposure pathways, concentrations of toxic chemicals, and populations (numbers, characteristics and habits) which aid the investigator in evaluating and quantifying exposure in a given situation.  (EPA 2004)
  2. A set of conditions or assumptions about sources, exposure pathways, amount or concentrations of agent(s)involved, and exposed organism, system or (sub) population (i.e., numbers, characteristics, habits) used to aid in the evaluation and quantification  of exposure(s) in a given situation.  (IPCS/OECD 2004)
  3. A set of assumptions concerning how an exposure may take place, including exposure setting, stressor characteristics, and activities that may lead to exposure.  (EPA 1998a)
  4. A combination of facts, assumptions, and inferences that define a discrete situation where potential exposures may occur.  These may include the source, the exposed population, the time frame of exposure, microenvironment(s), and activities.  Scenarios are often created to aid exposure assessors in estimating exposure.  (IPCS 2004)

Top of Page

exposure surface

A surface on a target where an agent is present.  Examples of outer exposure surfaces include the exterior of an eyeball, the skin surface, and a conceptual surface over the nose and open mouth.  Examples of inner exposure surfaces include the gastrointestinal tract, the respiratory tract, and the urinary tract lining.  As an exposure surface gets smaller, the limit is an exposure point.  (IPCS 2004)

exposure unit

In geographical information system applications, the geographical area in which a receptor moves and contacts the contaminated medium during the period of exposure.  (EPA 2004)

high-end exposure estimate

A plausible estimate of individual exposure or dose for those persons at the upper end of an exposure or dose distribution, conceptually above the 90th percentile, but not higher than the individual in the population who has the highest exposure or dose.  (EPA 2004)

incidental ingestion

Unintentional intake of small amounts of agents, particularly associated with children’s from hand-to-mouth activity.  (REAP 1995)

indirect contact

A mode of transmission of infection involving fomites or vectors.  Vectors may be mechanical (e.g., filth, flies) or biological (the disease agent undergoes part of its life cycle in the vector species).  (MERREA 2005)
RELATED TERMS: contact; contrast with direct contact

indirect exposure

Often defined as an exposure involving multimedia transport of agents from source to exposed individual. Examples include exposures to chemicals deposited onto soils from the air, chemicals released into the ground water beneath a hazardous waste site, or consumption of fruits or vegetables with pesticide residues.  (REAP 1995)

ingestion
  1. Swallowing (such as eating or drinking).  (EPA 2004)

The act of swallowing something through eating, drinking, or mouthing objects.  A hazardous substance can enter the body this way.  (ATSDR 2004)
RELATED TERMS: route of exposure

ingestion exposure

Exposure to a chemical by swallowing it (such as eating or drinking).  (EPA 2004)
RELATED TERMS: route of exposure

Top of Page

inhalation
  1. Breathing.  (EPA 2004)

The act of breathing. A hazardous substance can enter the body this way.  (ATSDR 2004)
RELATED TERMS: route of exposure

inhalation exposure

Exposure to a chemical by breathing it in.  (EPA 2004)
RELATED TERMS: route of exposure

inhalation unit risk          (ACRONYM: IUR)

The upper-bound excess lifetime cancer risk estimated to result from continuous exposure to an agent at a concentration of 1 μg/m3 in air.  The interpretation of unit risk would be as follows: if unit risk = 2 × 10-6 μg/m3, 2 excess tumors may develop per 1,000,000 people if exposed daily for a lifetime to a concentration of 1 μg of the chemical in 1 m3 of air.  (EPA 2004)

intake
  1. The process by which a substance crosses the outer boundary of an organism without passing an absorption barrier, e.g., through ingestion or inhalation.  (EPA 2004)
  2. The process by which an agent crosses an outer exposure surface of a target without passing an absorption barrier, i.e., through ingestion or inhalation (see Dose).  (IPCS 2004)
intake rate

Rate of inhalation, ingestion, and dermal contact depending on the route of exposure.  For ingestion, the intake rate is simply the amount of food containing the contaminant of interest that an individual ingests during some specific time period (units of mass/time).  For inhalation, the intake rate is the rate at which contaminated air is inhaled. Factors that affect dermal exposure are the amount of material that comes into contact with the skin, and the rate at which the contaminant is absorbed.  (EPA 2005b)

integrated exposure assessment

Cumulative summation (over time) of the magnitude of exposure to a toxic chemical in all media. (EPA 2005b)

lifetime exposure

Total amount of exposure to a substance that a human would receive in a lifetime (usually assumed to be 70 years).  (EPA 2005b, RAIS 2004)

longer-term exposure

Repeated exposure by the oral, dermal, or inhalation route for more than 30 days, up to approximately 10% of the life span in humans (more than 30 days up to approximately 90 days in typically used laboratory animal species).  (EPA 2003)

Top of Page

margin of exposure          (ACRONYM: MOE)
  1. The LED10 or other point of departure divided by the actual or projected environmental exposure of interest.  (EPA 2003)
  2. The point of departure divided by the actual or projected environmental exposure of interest.  (EPA 2004)
  3. The ratio of the no-observed adverse-effect-level to the estimated exposure dose.  (EPA 2005b)

Ratio of the no-observed-adverse-effect level (NOAEL) for the critical effect to the theoretical, predicted or estimated exposure dose or concentration.  (IPCS/OECD 2004)
RELATED TERMS: margin of safety

maximum exposed individual          (ACRONYM: MEI)
  1. The MEI represents the highest estimated risk to an exposed individual, regardless of whether people are expected to occupy that area.  (EPA 2004)
  2. Maximally (or most) exposed individual: The person with the highest exposure in a given population.  (EPA 2005b)
measure of exposure
  1. Describes stressor existence and behavior in the environment and its contact or co-occurrence with the assessment endpoint.  (EPA 1998a)
  2. The quantitative outcome of the exposure assessment.  For air toxics risk assessments, personal air concentration (or adjusted exposure concentration) is the metric of exposure for the inhalation route of exposure and intake rate is the metric of exposure for the ingestion route of exposure (EPA 2004)

A measurable characteristic of a stressor (such as the specific amount of mercury in a body of water) used to help quantify the exposure of an ecological entity or individual organism.  (EPA 2005b)
RELATED TERMS: metric of exposure

medium intake rate

The rate at which the medium crosses the outer exposure surface of a target during ingestion or inhalation.  (IPCS 2004)

metric of exposure

The quantitative outcome of the exposure assessment.  For air toxics risk assessments, personal air concentration (or adjusted exposure concentration) is the metric of exposure for the inhalation route of exposure and intake rate is the metric of exposure for the ingestion route of exposure.  (EPA 2004)
RELATED TERMS: measure of exposure

microenvironment

Surroundings that can be treated as homogeneous or well characterized in the concentrations of an agent (e.g., home, office, automobile, kitchen, store).  This term is generally used for estimating inhalation exposures.  (IPCS 2004)

multipathway exposure

When an organism is exposed to pollutants through more than one exposure pathway.  One example would be exposure through both inhalation and ingestion.  Another example would be ingestion of contaminated soil and ingestion of contaminated food.  (EPA 2004)
RELATED TERMS: multipathway assessment, multipathway risk

Top of Page

multiple exposure

SEE: multipathway exposure

pathway specific risk

The risk associated with exposure to a chemical agent or a mixture of chemicals via a specific pathway (e.g., inhalation of outdoor air).  (EPA 2004)

per capita intake rate

The average quantity of food consumed per person in a population composed of both individuals who ate the food during a specified time period and those that did not. (EPA 2005b)

pica
  1. Deliberate ingestion of non-nutritive substances such as soil.  (EPA 1997b)
  2. A behaviour characterized by deliberate ingestion of non-nutritive substances, such as soil.  (IPCS 2001)
  3. A behaviour characterized by deliberate ingestion of non-nutritive substances, such as soil.  (IPCS 2004)
point-of-contact measurement of exposure
  1. An approach to quantifying exposure by taking measurements of concentration over time at or near the point of contact between the chemical and an organism while the exposure is taking place.  (EPA 1992)
  2. Estimating exposure by measuring concentrations over time (while the exposure is taking place) at or near the place where it is occurring.  (EPA 2005b)
point of exposure

The place where someone can come into contact with a substance present in the environment.  (ATSDR 2004)
RELATED TERMS: exposure pathway

population dose

The summation of individual radiation doses received by all those exposed to the source or event being considered.  (RAIS 2004, SRA 2004)
RELATED TERMS: population exposure

population exposure

SEE: population dose

Top of Page

reasonable worst case
  1. A semiquantitative term referring to the lower portion of the high end of the exposure, dose, or risk distribution. The reasonable worst case has historically been loosely defined, including synonymously with maximum exposure or worst case, and assessors are cautioned to look for contextual definitions when encountering this term in the literature. As a semiquantitative term, it is sometimes useful to refer to individual exposures, doses, or risks that, while in the high end of the distribution, are not in the extreme tail. For consistency, it should refer to a range that can conceptually be described as above the 90th percentile in the distribution, but below about the 98th percentile. (compare maximum exposure range, worst case).  (EPA 1992)
  2. An estimate of the individual dose, exposure, or risk level received by an individual in a defined population that is greater than the 90th percentile but less than that received by anyone in the 98th percentile in the same population. Reasonably Available Control Technology (RACT): Control technology that is reasonably available, and both technologically and economically feasible. Usually applied to existing sources in nonattainment areas; in most cases is less stringent than new source performance standards. Reasonably Available Control Measures (RACM): A broadly defined term referring to technological and other measures for pollution control.  (EPA 2005b)

A semiquantitative term referring to the lower portion of the high end of the exposure, dose, or risk distribution.  The reasonable worst case has historically been loosely defined, including synonymously with maximum exposure or worst case.  As a semiquantitative term, it is sometimes useful to refer to individual exposures, doses, or risks that, while in the high end of the distribution, are not in the extreme tail.  For consistency, it should refer to a range that can conceptually be described as above the 90th percentile in the distribution, but below about the 98th percentile.  (EPA 2005d)
RELATED TERMS: worst case

refined exposure concentration

An estimate of exposure concentration that has been refined, usually by application of an exposure model, to better understand how people in a particular location interact with contaminated media.  (EPA 2004)
RELATED TERMS: adjusted exposure concentration

route

The way a chemical or pollutant enters an organism including tap water, milk, soft drinks, alcoholic beverages, after contact, e.g., by ingestion, inhalation, or dermal and water intrinsic to purchased foods.  (EPA 1997a)

route of exposure
  1. Route: The way a chemical or pollutant enters an organism after contact, e.g., by ingestion, inhalation, or dermal absorption.  (EPA 1997a)
  2. The way people come into contact with a hazardous substance.  Three routes of exposure are breathing (inhalation), eating or drinking (ingestion), or contact with the skin (dermal contact).  (ATSDR 2004)

The pathway (e.g., ingestion, inhalation, dermal) or vehicle by which a pathogen comes into contact with a host organism (e.g., food, soil, fomites, water).  (ILSI 2000)
RELATED TERMS: exposure route

short-term exposure

Repeated exposure by the oral, dermal, or inhalation route for more than 24 hours, up to 30 days.  (EPA 2003)

subchronic exposure
  1. Exposure to a substance spanning approximately 10% of the lifetime of an organism.  (EPA 2003)
  2. Of intermediate duration, usually used to describe studies or levels of exposure between 5 and 90 days.  (EPA 2005b, RAIS 2004)

A contact between an agent and a target of intermediate duration between acute and chronic.  (Other terms, such as “less-than-lifetime exposure,” are also used.)  (IPCS 2004)
RELATED TERMS: contrast with acute exposure, chronic exposure

Top of Page

vector
  1. An animate intermediary in the indirect transmission of an agent that carries the agent from a reservoir to a susceptible host.  (CDC 2005)
  2. An insect or any living carrier that transports an infectious agent from an infected individual or its wastes to a susceptible individual or its food or immediate surroundings.  (MERREA 2004)

The above definitions refer to biological disease vectors.  Mechanical disease vector is sometimes used to describe inanimate objects that facilitate disease transmission.  In the molecular biology context a vector is a laboratory manipulated biomolecule that is used to facilitate delivery of an associated biomolecule to a tissue or organ within an organism.  The most common usage of vector in genetic engineering refers to genetic material (e.g. DNA plasmid) that is ligated (chemically fused) to a gene of interest to allow transfer of that gene to a different organism. 

vehicle

An inanimate intermediary in the indirect transmission of an agent that carries the agent from a reservoir to a susceptible host.  (CDC 2005)

worst case
  1. A semiquantitative term referring to the maximum possible exposure, dose, or risk, that can conceivably occur, whether or not this exposure, dose, or risk actually occurs in a specific population.  (EPA 2005d) 
  2. The situation or input that forces an algorithm or data structure most time or resources.  (NIST 2005)

A method of conducting an exposure assessment in which the most conservative value of each input parameter is selected. (AIHA 2000)
RELATED TERMS: reasonable worst case, maximum individual risk

Top of Page

Go to Thesaurus Contents
Go to Thesaurus Index

 


Jump to main content.