Pollutant glossary

A glossary of the terms used whenever pollutants are discussed P055

The sealing of rotating fluid handling equipment and the ultimate containment of possible pollutants are two subjects that go “and in hand”. Since we are involved in these subjects we might as well learn the language, so here is a list of the common pollution terms you may encounter.

Glossary (Environmental Defense Fund)

Acute ToxicityNegative health effects from a single dose or exposure to a toxic chemical or other toxic substance.
Adverse Health EffectAbnormal or harmful effect to an organism (e.g., a person) caused by exposure to a chemical. It includes results such as death or other illnesses, altered body and organ weights, altered enzyme levels, etc.
Ambientas in the surrounding environment. The medium surrounding or contacting an organism (e.g., a person), such as outdoor air, indoor air, water, or soil, through which chemicals or pollutants can be carried and can reach the organism.
Antagonism (chemical)When the adverse effect or risk from two or more chemicals interacting with each other is less than what it would be if each chemical was acting separately.
Attainment AreaA geographic area that meets the National Ambient Air Quality Standard (NAAQS) is called an attainment area. An area with too much of a pollutant to meet the NAAQS for that pollutant is called a non-attainment area. NAAQSs are concentration levels for each of six criteria air pollutants, above which adverse effects on human health may occur. The six criteria pollutants are used as indicators of air quality.
Authoritative Scientific or Regulatory OrganizationOrganizations that either have regulatory authority over a subject (such as control of certain chemicals in certain contexts) or are widely recognized as using the best available scientific practices and peer review processes in developing their policies and recommendations about that subject. Scorecard’s lists of recognized health hazards come from lists already put together by authoritative organizations.
Benzene-EquivalentsScorecard’s common unit of comparison for carcinogens, so that the seriousness of a release of one carcinogen can be compared to a release of another. Scorecard’s scoring system takes into account both a chemical’s toxicity and the amount of exposure resulting from a release. It uses benzene as the standard for comparison and converts releases of other carcinogens into pounds of benzene-equivalents.


A range of values used for grouping purposes. In statistics, values are often grouped into bins to make generalizations, or to draw comparisons. For example, Scorecard usually places chemicals in bins based on their toxicity using 10 bins. Bin 1 includes the 10% of chemicals with the lowest toxicity, while bin 10 includes the 10% of chemicals with the highest toxicity .
BioaccumulationBioaccumulation is the process by which chemicals concentrate in an organism. For example, DDT concentrates in fish and birds that eat fish. This concentration effect is expressed as the ratio of the concentration of the chemical in an organism (like a fish) to its concentration in the surrounding medium (usually water). Bioaccumulation refers to the uptake of chemicals both from water (bioconcentration) and from ingested food and sediment.
CancerCancer is a group of more than 100 different diseases that occur when a cell, or group of cells, grows in an unchecked, uncontrolled, or unregulated manner. It can involve any tissue of the body and can have many different forms in each body area. Most cancers are named for the type of cell or the organ in which they begin, such as leukemia or lung cancer.
Cancer Potency EstimateAn estimate of a chemical’s likelihood to cause cancer, generally derived from animal studies and extrapolated to humans.
Cancer Risk ScoreHow a chemical’s estimated cancer risk compares with the cancer risk from other chemicals, after being converted into a common unit of comparison.
CarcinogenA chemical or physical agent capable of causing cancer.
Cardiovascular and Blood ToxicityThe adverse effects on the heart or blood systems which result from exposure to toxic chemicals.
CAS Registry NumberA unique number assigned to a chemical by the Chemical Abstracts Service, a division of the American Chemical Society.
Chemical CarcinogenesisCancer caused by exposure to a chemical or chemicals.
Chemical InteractionWhen two or more chemicals interact with each other, resulting in either antagonistic or synergistic effects.
Chronic ToxicityAdverse health effects from repeated doses of a toxic chemical or other toxic substance over a relatively prolonged period of time, generally greater than one year.
Connective TissueOne of the four basic types of tissue in the body; a material consisting of fibers (e.g., tendons or ligaments) that form a framework to support other body tissues (e.g., muscles).
ContaminantAny substance or material in a system (the environment, the human body, food, etc.) where it is not normally found; or, a substance in a system where it is naturall occurring , but found in an unusually high concentration.
DermalReferring to the skin. Dermal absorption means absorption through the skin
Developmental ToxicityAdverse effects on the developing child which result from exposure to toxic chemicals or other toxic substances. Adverse effects can include birth defects, low birth weight, and functional or behavioral weaknesses that show up as the child develops.
Disease IncidenceThe rate of new occurrences of a disease
Dose Assessment/RelationshipThe amount of a chemical that an organism (such as a person) is exposed to is called the dose, and the severity of the effect of that exposure is called the response. A dose-response assessment is a scientific study to determine the relationship between dose and response, and how much dose is correlated with how much response.
Ecological Health RankingHow a chemical’s adverse effect on plants and animals compares with that of other chemicals in a relative ranking system
Ecological Risk AssessmentA process used to estimate how likely it is that there will adverse effects on plants or animals from exposure to chemicals (or to other potential stress, such as the draining of a wetland). The process includes problem formulation, characterization of exposure, characterization of ecological effects, and risk characterization.
EcotoxicityBeing poisonous or harmful to plants or animals in some degree.
Endocrine ToxicityAny adverse structural and/or functional changes to the endocrine system (the system that controls hormones in the body) which may result from exposure to chemicals. Endocrine toxicity can harm human and animal reproduction and development.
Environmental FateWhere a substance ends up after it is released into the environment. Environmental fate depends on many factors, including transport (e.g., wind, runoff) and transformation processes (e.g., degradation).
EPA or U.S. EPAUnited States Environmental Protection Agency.


Epithelial Tissue

One of the four basic tissues of the body.

The cell linings covering most of the internal

and external surface of the body and its

organs, e.g. stomach lining.


Exposure Assessment

Identifying the ways in which chemicals may

reach individuals (e.g., by breathing);

estimating how much of a chemical an

individual is likely to be exposed to; and

estimating the number of individuals likely to

be exposed.


Exposure Potential

An estimate of the total dose of a chemical

received by an exposed organism (e.g., a

person) or by a population, not just via one

pathway or medium but from all likely



Fate and Exposure Modeling

The scientific process used to predict where

chemicals “end up” after being released into

the environment. For example: a chemical

may be emitted into the air, but most of it

might end up in groundwater, because of the

chemical’s particular physical properties.



The adverse health effect a chemical has on

genes and chromosomes, primarily gene

mutations, chromosome aberrations and

changes in chromosome number.

Genotoxicity may be indicative of

cancer-causing chemicals.


Good Neighbor Agreement

A Good Neighbor Agreement (GNA) is one

important way that a community and a

company with a facility in that community can

work towards improving the environmental

performance of the company’s facility.



The time in which the concentration of a

chemical in the environment is reduced by



Hazard Identification

The first step in the risk assessment

process. This step includes the identification

of a chemical of concern and its potential

adverse effects.


Hazard Indicator

A quantitative measurement of a chemical’s

hazard. Scorecard includes hazard indicators

for numerous endpoints, including human

health, ecological health, and combined

human and ecological health. These are

based on different combinations of factors,

such as toxicity, persistence, and exposure



Hazard Ranking

How a chemical’s adverse effects compare

with other chemicals in a ranking system.


Health Hazard

Adverse effects to a living organism.


Human Health Ranking

How a chemical’s adverse health effects on

humans compare with the same effects from

other chemicals, in a ranking system.



Adverse effects on the normal functioning of

the immune system, caused by exposure to

a toxic chemical. Changes in immune

function could produce higher rates of

infectious diseases or cancer, or more severe

cases of those diseases. Immunotoxic

chemicals can also cause auto-immune

disease or allergic reactions.


Industrial Sector

Standard Industrial Classification (SIC) codes

are a system of numerical codes that

categorize industrial facilities by the type of

activity in which they are engaged. For

example, SIC code 2911 refers to petroleum

refineries. Each code number represents an

industrial sector.



Swallowing (such as eating or drinking).

Chemicals can get into or onto food, drink,

utensils, cigarettes, or hands where they can

then be ingested.



Breathing. Once inhaled, contaminants can

be deposited in the lungs, taken into the

blood, or both.


Integrated Health Ranking

How a chemical’s adverse human and

ecological health effects compare with those

of other chemicals, in a relative ranking



Kidney Toxicity

Adverse effects on the kidney, urethra or

bladder caused by exposure to a toxic

chemical. Some such chemicals can cause

acute injury to the kidney; others can

produce chronic changes that can lead to

kidney failure or cancer.



Any of several cancers of blood-forming

organs (usually bone marrow cells) which

cause the uncontrolled production of

abnormal white blood cells (leukocytes).


Liver and Gastrointestinal Toxicity

Adverse effects to the structure and/or

function of the liver, gall bladder or

gastrointestinal tract caused by exposure to

a toxic chemical. The liver is frequently

subject to chemical-induced injury because of

its role as the body’s principal site of

metabolism. Chemicals that damage the

liver can cause diseases such as hepatitis,

jaundice, cirrhosis and cancer.


Musculoskeletal Toxicity

Adverse effects to the structure and/or

function of the muscles, bones and joints

caused by exposure to a toxic chemical.

Exposures to coal dust and cadmium, for

example, have been shown to cause adverse

changes to the musculoskeletal system.

Examples of musculoskeletal diseases which

can be caused by exposure to toxic

chemicals include the bone disorders

arthritis, fluorosis, and osteomalacia.



A change in the genetic material of a living

organism, usually in a single gene, which can

be passed on to future generations.



Same as kidney toxicity.



Adverse effects on the structure or function

of the central and/or peripheral nervous

system caused by exposure to a toxic

chemical. Symptoms of neurotoxicity include

muscle weakness, loss of sensation and

motor control, tremors, cognitive alterations

and autonomic nervous system dysfunction.



The National Institute for Occupational Safety

and Health, a federal agency that conducts

research on occupational safety and health

questions and makes recommendations to

federal OSHA about new standards for

controlling toxic chemicals in the workplace.


Noncancer Risk Score

How a chemical’s non-cancer risk compares

with the non-cancer risk from other

chemicals, after being converted into a

common unit of comparison.



The Organization of Economic Cooperation

and Development (OECD), a Paris-based

intergovernmental organization with 29

member countries. A forum in which

governments can develop common solutions

to various social problems, including issues

of toxic chemical management.


Ozone Depleting Substance

Ozone in the stratospheric layer of the

Earth’s atmosphere keeps 95-99% of the

Sun’s ultraviolet radiation from striking the

Earth. Various chemicals deplete the ozone

layer by accelerating processes that destroy

ozone, increasing the amount of ultraviolet

radiation that reach the surface. This

radiation can cause genetic damage, eye

damage and damage to marine life.



In Scorecard, persistence generally refers to

environmental persistence: the length of

time a chemical stays in the environment,

once introduced. Persistent chemicals do not

break down easily in the environment.


Persistent Organic Pollutants (POPs)

Persistent Organic Pollutants (POPs) are

chemicals, chiefly compounds of carbon, that

persist in the environment, bioaccumulate

through the food chain, and pose a risk of

causing adverse effects to human health and

the environment.



Sensitization or heightened reactivity of the

skin to sunlight, usually due to the action of

certain drugs.


Pollution Prevention

An approach that avoids creating toxic

chemical emissions and waste in the first

place; it reduces the amount of toxic

chemicals that businesses need to use in

their operations.



Occurring sometime after birth, with

reference to the newborn infant.



Preceding birth, with reference to the fetus.


Proposition 65

Formally known as the Safe Drinking Water

and Toxics Enforcement Act , Proposition 65

was enacted in California by direct ballot

initiative in November 1986. Generally, it

requires warnings to citizens when they are

exposed to chemicals known to cause cancer

or birth defects or other reproductive harm,

and also forbids the discharge of those same

chemicals into sources of drinking water in



Recognized Human Health Hazard

Authoritative national and international

scientific and regulatory agencies have

identified some chemicals that cause specific

adverse health effects with enough certainty

to consider the effect a recognized hazard of

the chemical. To date, such efforts have

been focused on cancer, reproductive

toxicity, and developmental toxicity.

Scorecard uses lists developed under

California’s Proposition 65 (which combine

the hazard identification efforts of various

authoritative bodies) as its primary reference

for identifying these chemicals.


Reference Concentration (RfC)

An estimate of the daily inhalation dose,

expressed in terms of an ambient

concentration, that can be taken daily over a

lifetime without appreciable risk.


Reference Dose (RfD)

An estimate of the daily ingestion dose,

expressed in terms of amount per unit of

body weight, that can be taken daily over a

lifetime without appreciable risk.


Reproductive Toxicity

Adverse effects on the male and/or female

reproductive systems caused by exposure to

a toxic chemical. Reproductive toxicity may

be expressed as alterations in sexual

behavior, decreases in fertility or fetal loss

during pregnancy. Some official definitions of

reproductive toxicity, for example in

California’s Proposition 65, include

developmental toxicity as part of

reproductive toxicity.


Respiratory Toxicity

Adverse effects on the structure or function

of the respiratory system caused by

exposure to a toxic chemical. Respiratory

toxicants can produce a variety of acute and

chronic pulmonary conditions, including local

irritation, bronchitis, pulmonary edema,

emphysema and cancer.



The probability that damage to life, health,

and/or the environment will occur as a result

of a given hazard (such as exposure to a

toxic chemical). Some risks can be measured

or estimated in numerical terms (e.g., one

chance in a hundred).


Risk Assessment

An organized process used to describe and

estimate the amount of risk of adverse

human health effects from exposure to a

toxic chemical (how likely or unlikely it is that

the adverse effect will occur). How reliable

and accurate this process is depends on the

quantity and quality of the information that

goes into the process. The four steps in a

risk assessment of a toxic chemical are

hazard identification, dose-response

assessment, exposure assessment, and risk



Risk Assessment Value

Risk assessment values are numbers that

help define the level of health risk, both

cancer and noncancer, posed by a toxic

chemical. They are derived from

dose-response assessments of animal or

human studies that indicate a chemical can

cause an adverse health effect.


Risk Characterization

An organized process used to evaluate,

summarize, and communicate information

about the likelihood of adverse health or

ecological effects from particular exposures

to a toxic chemical in the environment, i.e.

how individuals or populations may be

affected. It includes discussion of the kind of

evidence it uses and how strong that

evidence is. Risk characterization is the final

step in the process of risk assessment.


Risk Management

The process of actually trying to reduce risk,

e.g., from a toxic chemical, and/or of trying

to keep it under control. Risk management

involves not just taking action, but also

analyzing and selecting among options and

then evaluating their effect.


Route of Exposure

The avenue by which a chemical comes into

contact with an organism (such as a person).

Possible routes include inhalation, ingestion,

and dermal contact.


Safety Assessment

The process of evaluating the safety (or lack

of safety) of a chemical in the environment

based upon its toxicity and current levels of

human exposure.


Screening Level

Screening level information about a

chemical’s toxicity or exposure potential is

derived from readily available information

using methods that do not require extensive

analyses to support preliminary evaluations

of chemical safety. Screening level

information is useful and necessary for

ranking potential problems, directing more

detailed investigations, and taking

preventative action.


Screening Risk Assessment

A risk assessment performed using available

data and many assumptions to identify toxic

chemical releases that have a higher

probability of posing health risks. If potential

health risks are identified, further

investigation or risk reducing actions may be



SIC Code

Standard Industrial Classification (SIC) codes

are a system of numerical codes that

categorize industrial facilities by the type of

activity in which they are engaged. For

example, SIC code 2911 refers to petroleum

refineries. All companies conducting the

same type of business, regardless of their

size, have the same SIC code. The basic SIC

code is two digits long.



The Screening Information Data Set created

by the member countries of the Organization

for Economic Cooperation and Development

(OECD) in 1990, for purposes of screening

high-production-volume chemicals used in

those countries (including the U.S.). The

purpose of the SIDS program is to complete

initial screening tests on those chemicals to

identify their potential hazards to human

health and the environment, so that risk

assessments can then be done for the

chemicals with sufficient hazard potential.

The data set is a list of the tests and other

information about a chemical that OECD

considers to be the necessary minimum for

purposes of this preliminary screening.


Skin and Sense Organ Toxicity

Adverse effects on the skin or sensory

organs caused by exposure to a toxic

chemical. Sense organs include eyes, ears,



Suspected Human Health Hazard

These are hazards to human health from a

chemical that are indicated by some scientific

evidence, but that have not been

conclusively determined by an authoritative

scientific or regulatory organization.

Scorecard uses numerous reports in the

scientific or regulatory literature, and

information abstracted from major

toxicological databases, as its sources for

identifying chemicals with suspected human

health hazards of different kinds. Inclusion

of a chemical on a “suspected” list should be

viewed as a preliminary indication that the

chemical may cause this effect, rather than a

definitive finding that it does.


Synergism (chemical)

When the adverse effect or risk from two or

more chemicals interacting with each other is

greater than what it would be if each

chemical was acting separately.



A level of chemical exposure below which

there is no adverse effect and above which

there is a significant toxicological effect.



Scorecard’s common unit of comparison for

non-carcinogens, so that the seriousness of

a release of one non-carcinogen can be

compared to a release of another.

Scorecard’s scoring system takes into

account both a chemical’s toxicity and the

amount of exposure resulting from a

release. It uses toluene as the standard for

comparison and converts releases of other

non-carcinogen into pounds of



Total Hazard Value

A quantitative value representing the total

hazard of a chemical substance, derived by

integrating the chemical’s human health

effects, ecological effects, and exposure



Toxic Equivalency Potentials

How a chemical’s adverse human health

effects compare with those of other

chemicals, after being converted into a

common unit of comparison (Scorecard uses

benzene-equivalents for carcinogens and

toluene-equivalents for non-carcinogens).



The extent, quality, or degree of being

poisonous or harmful to humans or other

living organisms.


Toxicity Weight

How a chemical’s toxicity – either chronic,

acute, or both – compares with other

chemicals in a relative ranking system.



Toxics Release Inventory. Under Section 313

of the Emergency Planning and Community

Right-To-Know Act of 1986 (EPCRA), certain

manufacturing facilities are required to report

the amounts of approximately 650 toxic

chemicals that they release into the

environment or produce as waste. The TRI

inventory is, at present, the only source of

information used by Scorecard on

environmental releases of toxic chemicals

and waste management of those chemicals.


TRI Chemicals

A list of about 650 toxic chemicals or

chemical categories included in the Toxics

Release Inventory (TRI). In general, TRI

chemicals are ones that U.S. EPA has found

can be reasonably anticipated to cause acute

or chronic adverse human health effects, or

adverse environmental effects.


TRI Facilities

Facilities that are required to report their

environmental releases and chemical waste

management of a prescribed list of

approximately 650 toxic chemicals to the

Toxics Release Inventory (TRI). There are

over 20,000 facilities included in the TRI in




The Toxic Substances Control Act (TSCA) of

1976. In theory, this law gave U.S. EPA the

power to test, regulate, and screen nearly all

chemicals produced or imported into the

United States. However, after more than two

decades, TSCA’s promise is almost entirely




A chemical’s tendency to evaporate into the

air, usually measured in units of Pascals,

atmospheres, or pounds per square inch.

Chemicals with high volatility tend to

evaporate readily.


Weight of Evidence

The evaluation of published information

about a chemical’s toxicity and exposure

potential that leads to a conclusion about

that chemical’s safety or hazard. Important

factors include the adequacy and number of

available studies; the consistency of results

across studies; and the biological plausibility

of dose-response relationships.


  • On February 16, 2018