Home » Boron » Glossary



Glossary over Boron


The process of taking in. For a person or an animal, absorption is the process of a substance getting into the body through the eyes, skin, stomach, intestines, or lungs. (Source: ATSDR Glossary of Terms  )



To take up and hold (a gas, liquid, or dissolved substance) in a thin layer of molecules on the surface of a solid substance. (Source: US EPA Acid Rain Glossary  )


Adverse health effect

A change in body function or cell structure that might lead to disease or health problems. (Source: ATSDR Glossary of Terms  )

Agency for Toxic Substances and Disease Registry

The Agency for Toxic Substances and Disease Registry (ATSDR) is an agency of the U.S. Department of Health and Human Services (HHS). As mandated by the federal superfund law, the agency assesses health risks from hazardous waste sites on the EPA's National Priorities List. ATSDR determines if additional health studies are needed at these sites, provides health advisories and publishes toxicological profiles on chemicals found at hazardous waste sites.

ATSDR also maintains exposure registries of people exposed to certain substances. (Source: ATSDR website  )

American Chemical Society

"The American Chemical Society (ACS) is a self-governed individual membership organization that consists of more than 159,000 members at all degree levels and in all fields of chemistry. The organization provides a broad range of opportunities for peer interaction and career development, regardless of professional or scientific interests. The programs and activities conducted by ACS today are the products of a tradition of excellence in meeting member needs that dates from the Society's founding in 1876." (Source: ACS website )


A dark brown or green igneous rock, formed by the cooling and solidification of molten lava on or near the Earth's surface. (Source: GreenFacts)


Bioaccumulation is used to describe the increase in concentration of a substance in an organism over time.

Bioaccumulative substances tend to be fat soluble and not to be broken down by the organism. (Source: GreenFacts )


Biologic intake

The process by which a substance crosses the outer boundary of an organism without passing an absorption barrier, e.g. through ingestion or inhalation. (Source: US EPA glossary )


Biologic uptake

The transfer of substances from the environment to plants, animals, and humans. (Source: ATSDR Glossary of Terms )



The term biomagnification refers to the progressive build up of persistent substances by successive trophic levels - meaning that it relates to the concentration ratio in a tissue of a predator organism as compared to that in its prey. (Source: GreenFacts)

Blood serum

Clear, watery fluid of the blood that separates when blood clots. (Source: GreenFacts)



In the environment, boron is present in the form of borate, combined with oxygen and other elements. Borates are salts or esters of boric acid. They are widely found in nature, and are present in oceans, sedimentary rocks, coal, shale and soils. (Source: GreenFacts)



Ore of boron consisting of sodium borate, a mineral salt found in alkaline (non-acidic, see pH) deposits. (Source: GreenFacts)


Boric acid

Boric acid is a chemical compound containing boron, hydrogen and oxygen. It is a mild acid. It exists in the form of colorless crystals or a white powder and dissolves in water. (Source: GreenFacts)



A substance, factor or situation that causes or induces cancer. (Source: GreenFacts )


The basic subunit of any living organism; the simplest unit that can exist as an independent living system. There are many different types of cells in complex organisms such as humans, each with specific characteristics. (Source: GreenFacts)


Chemical element

A substance which cannot be separated into its constituent parts and still retains its chemical identity. For example, sodium (Na) is an element. (Source: US EPA Drinking Water Glossary  )


Circulatory system

The system that contains the heart and the blood vessels and moves blood throughout the body. This system helps tissues get enough oxygen and nutrients, and it helps them get rid of waste products. The lymph system, which connects with the blood system, is often considered part of the circulatory system. (Source: NCI Dictionary of cancer terms  )



Clay is a sediment composed of tiny mineral particles that are formed by the weathering and breaking down of rocks and minerals. Clay particles are the smallest inorganic component of soil, measuring no more than 2 µm in diameter. Clay has a low permeability. (Source: GreenFacts)



A material made up of two or more elements combined in a fixed ratio. (Source: CoRIS glossary  )



The amount of a chemical or substance present in a particular quantity of soil, water, air, food, blood, hair, urine, breath, or any other media. (Source: GreenFacts)



To desorb is to remove a gas, liquid, or dissolved substance from a surface on which it is adsorbed. (Source: GreenFacts)


Drainage area

A drainage area is the total surface area, upstream of a point on a stream, where the water from rain, snowmelt, or irrigation which is not absorbed into the ground flows over the ground surface, back into streams, to finally reach that point. (Source: GreenFacts)

Dry Weight

The plant, animal, or other material containing the chemical of interest is dried to remove all water from the material. The amount of the chemical found in subsequent analysis is then expressed as weight of chemical divided by weight of the dried material which once contained it. (Source: GreenFacts)


The complex system of plant, animal, fungal, and microorganism communities and their associated non-living environment interacting as an ecological unit.

Ecosystems have no fixed boundaries; instead their parameters are set to the scientific, management, or policy question being examined. Depending upon the purpose of analysis, a single lake, a watershed, or an entire region could be considered an ecosystem. (Source: US EPA Glossary of Climate Change Terms   )

epa cancer classification

Standard US EPA Cancer Classification

Standard US EPA classification (1986)

Standard EPA classification categorization descriptions

EPA cancer guidelines evolution (1986-2003)

Standard US EPA classification (1986)

Chemicals or other agents in the environment assessed by US EPA (Environmental Protection Agency) are classified in five groups based on the existing scientific evidence for carcinogenicity.

Group A: "Human Carcinogen"
There is enough evidence to conclude that it can cause cancer in humans.
EPA definition

Group B1: "Probable Human Carcinogen"
There is limited evidence that it can cause cancer in humans, but at present it is not conclusive.
EPA definition

Group B2: "Probable Human Carcinogen"
There is inadequate evidence that it can cause cancer in humans but at present it is far from conclusive.
EPA definition

Group C: "Possible Human Carcinogen"
There is limited evidence that it can cause cancer in animals in the absence of human data, but at present it is not conclusive.
EPA definition

Group D: "Not Classifiable as to Human Carcinogenicity"
There is no evidence at present that it causes cancer in humans.
EPA definition

Group E: "Evidence of Non-Carcinogenicity for Humans"
There is strong evidence that it does not cause cancer in humans.
EPA definition

Standard EPA classification categorization descriptions

Group A: "Human Carcinogen"

"This group is used only when there is sufficient evidence from epidemiologic studies to support a cusal association between exposure to the agents and cancer."

Group B (1 and 2): "Probable Human Carcinogen"

"This group includes agents for which the weight of evidence of human carcinogenicity based on epidemiologic studies is "limited" and also includes agents for which the weight of evidence of carcinogenicity based on animal studies is "sufficient". The group is divided into two subgroups. Usually, Group B1 is reserved for agents for which there is limited evidence of carcinogenicity from epidemiological studies. It is reasonable, for practical purposes, to regard an agent for which there is "sufficient evidence of carcinogenicity " in animals as if it presented a carcinogenic risk to humans. Therefore, agents for which there is "sufficient" evidence from animal studies and for which there is "inadequate evidence" or "no data" from epidemiologic studies would usually be categorized under Group B2."

Group C: "Possible Human Carcinogen"

"This group is used for agents with limited evidence of carcinogenicity in animals in the absence of human data. It includes a wide variety of evidence, e.g., (a) a malignant tumor response in a single well-conducted experiment that does not meet conditions for sufficient evidence, (b) tumor responses of marginal statistical significance in studies having inadequate design or reporting, (c) benign but not malignant tumors with an agent showing no response in a variety of short-term tests for mutagenicity, and (d) responses of marginal statistical significance in a tissue known to have a high or variable background rate."

Group D: "Not Classifiable as to Human Carcinogenicity"

"This group is generally used for agents with inadequate human and animal evidence of cercinogenicity or for which no data are available."

Group E: "Evidence of Non-Carcinogenicity for Humans"

"This group is used for agents that show no evidence for carcinogenicity in at least two adequate animal tests in different species or in both adequate epidemiologic and animal studies.

The designation of an agent as being in Group E is based on the available evidence and should not be interpreted as a definitive conclusion that the agent will not be a carcinogen under any circumstances."

EPA cancer guidelines evolution

EPA published final cancer guidelines in 1986. As with other risk assessment guidelines, EPA has been working to revise the cancer guidelines to reflect advances in scientific understanding as well as experience in using them. Listed below are EPA's initial cancer guidelines and draft revisions.

2003 Drafts:
2003 Draft Final Guidelines:  As announced in the Federal Register on March 3, 2003, the Draft Final Guidelines for Carcinogen Risk Assessment are being made available for public comment.

2003 Draft Supplemental Guidance:  As announced in the Federal Register on March 3, 2003, the draft Supplemental Guidance for Assessing Cancer Susceptibility from Early-Life Exposure to Carcinogens is being made available for public comment. This document is intended to augment the cancer guidelines by focusing on cancer risks resulting from exposure during childhood.

Current Agency Guidance:
1999 Draft Revised Guidelines:  As announced in the Federal Register on November 29, 2001, the July 1999 draft Revised Guidelines for Carcinogen Risk Assessment will continue to serve as EPA's interim guidance to EPA risk assessors preparing cancer risk assessments until final Guidelines are issued.

 1986 Initial Cancer Guidelines: 1986 Guidelines for Carcinogen Risk Assessment In 1986, EPA published a set of risk assessment guidelines, including Guidelines for Carcinogen Risk Assessment (Federal Register 51 (185) 33992-34003, 24 September 1986).

European Commission Scientific Committee on Toxicity, Ecotoxicity and the Environment

The Scientific Committee on Toxicity, Ecotoxicity and the Environment (CSTEE) was created by the European Commission to address "scientific and technical questions relating to examination of the toxicity and ecotoxicity of chemical, biochemical and biological compounds whose use may have harmful consequences for human health and the environment." (Source: CSTEE website )


Contact of the cells of an organism with a substance, micro-organism or radiation. In the case of humans, this may involve contact with a substance or agent by swallowing, breathing, or through the skin or eyes. Exposure may be short-term [acute exposure], of intermediate duration, or long-term [chronic exposure].

Exposure can be divided into external and internal.

External exposure refers to the whole dose to which an organism is exposed.

Internal exposure refers only to that fraction of the initial chemical dose that is absorbed and distributed throughout the body via systemic circulation. (Source: GreenFacts)



The ability of people or animals to produce healthy offspring in abundance.

Unlike fecundity, which measures a potential ability, fertility measures the actual number of offspring of an individual, a couple, a group or a population. It is evaluated by the time to achieve pregnancy.

Please note that "fertility" corresponds to "fécondité" in French and "fecundidad" in Spanish whereas the French word "fertilité" and the Spanish word "fertilidad" mean "fecundity". (Source: GreenFacts)

Fossil fuel(s)

A general term for buried combustible geologic deposits of organic materials, formed from decayed plants and animals that have been converted to crude oil, coal, natural gas, or heavy oils by exposure to heat and pressure in the Earth's crust over hundreds of millions of years. (Source: US EPA Glossary of Climate Change terms  )

Geothermal energy

The word geothermal comes from the Greek words geo (earth) and therme (heat). So, geothermal energy is heat from within the earth. We can use the steam and hot water produced inside the earth to heat buildings or generate electricity. Geothermal energy is a renewable energy source because the water is replenished by rainfall and the heat is continuously produced inside the earth. (Source: The U.S. Energy Information Administration, Energy Kids page   )



Water beneath the Earth's surface in the spaces between soil particles and between rock surfaces. (Source: ATSDR Glossary of Terms  )

Health canada

"Health Canada is the federal department responsible for helping the people of Canada maintain and improve their health ."

"In partnership with provincial and territorial governments, Health Canada provides national leadership to develop health policy, enforce health regulations, promote disease prevention and enhance healthy living for all Canadians."

See also the Health Canada Environment page:  (Source: Health Canada website )


Hydroxy-oxide is a chemical compound containing oxygen (O), the hydroxyl (OH) anion and some other chemical element. For example, NiOOH is the chemical formula for nickel hydroxy-oxide, and FeOOH that of iron hydroxy-oxide. (Source: GreenFacts)


The act of swallowing something through eating, drinking, or mouthing objects. A hazardous substance can enter the body this way. (Source: ATSDR Glossary of Terms  )


The act of breathing.

A hazardous substance can enter the body by inhaling an airborne substance or contaminant in the form of gas, fumes mists, vapors, dusts, or aerosols. Once inhaled, contaminants can be deposited in the lungs and/or transported into the blood. (Source: GreenFacts)

International Programme on Chemical Safety

The International Programme on Chemical Safety (IPCS) was established in 1980 by the WHO, the UNEP and the ILO (International Labour Organisation) "for the early warning and prevention of harmful effects of chemicals to which humans were being increasingly exposed, and for the assessment of the potential risks to human health."

It has collaborated to and published many highly recognized scientific publications.

Most publications are availaible from the INCHEM website, "a means of rapid access to internationally peer reviewed information on chemicals commonly used throughout the world, which may also occur as contaminants in the environment and food." Publications include:


An ion is an atom or molecule that is not electrically neutral, but instead carries a positive or negative electrical charge, which is due to the loss or gain of one or more electrons.

An anion is a ion with a negative electrical charge, e.g. chloride (CI-), as opposed to a cation which is an ion with a positive electrical charge, e.g. sodium (Na+). (Source: GreenFacts)

Mass (weight) Units

The Metric System of Measurements uses the mass units: gram (g), kilogram (kg) and tonne (t).

1000 g = 1 kg
1000 kg = 1 tonne

Adding prefixes of the International System of Units (SI) allows to express weight as multiples or fractions of 1 gram:

1 gigatonne (Gt) =1 000 000 000 000 000 g
1 megatonne (Mt) =1 000 000 000 000 g
1 tonne (t) =1 000 000 g
1 kilogram (kg) =1 000 g
1 gram (g) =1 g
1 milligram (mg) =0.001 g
1 microgram (µg) =0.000 001 g
1 nanogram (ng) =0.000 000 001 g
1 picogram (pg) =0.000 000 000 001g

Imperial and US weight units can also be expressed as metric units:

Metric units
1 US ton (ton) =0.907 tonne
1 UK ton (ton) =1.016 tonne
1 lb (pound) =453.59 g
1 oz (ounce) =28.35g

Further information on the International System of Units (SI) is provided by the International Bureau of Weights and Measures (BIPM) 


The conversion or breakdown of a substance from one form to another by an enzyme. (Source: GreenFacts, based on ATSDR Glossary of Terms )


Natural organic matter

Organic matter originating from plants and animals present in natural (untreated or raw) waters, for example, in lakes, rivers and reservoirs. (Source: GreenFacts)


No Observed Adverse Effect Level

The highest tested dose of a substance that has been reported to have no harmful (adverse) health effects on people or animals. (Source: ATSDR Glossary of Terms   )


Oxidizing agent

Any substance, such as oxygen (O2) or chlorine (Cl2), that will readily add (take on) electrons. The opposite is a reducing agent. (Source: US EPA Drinking Water Glossary   )


Parts per million

A weight to weight ratio used to describe concentrations. Parts per million (ppm) is the number of units of mass of a contaminant per million units of total mass. (Source: GreenFacts)



pH is a measure of the concentration of protons (H+) in a solution and, therefore, its acidity or alkalinity. The concept was introduced by S.P.L. Sørensen in 1909. The p stands for the German "Potenz", meaning power or concentration, and the H for the hydrogen ion (H+). In layman's terms , the "pH" value is an approximate number between 0 and 14 that indicates whether a solution is acidic (pH < 7), basic (pH > 7) or neither (pH = 7) [neutral]. (Source: GreenFacts )



The pharynx is the part of the digestive system of many animals immediately behind the mouth and in front of the esophagus. In mammals, it is where the digestive tract and the respiratory tract cross, commonly called the "throat" (which term may also include the larynx). The human pharynx is bent at a sharper angle than other mammal pharynges, enabling us to produce a wider variety of sounds, but also putting us in danger of choking.

The human pharynx is divided into three sections: the nasopharynx, lying behind the nasal cavity; the oropharynx, behind the oral cavity [including soft palate, base of the tongue and tonsils]; and the laryngopharynx [also named hypopharynx], posterior to the larynx. (Source: GreenFacts )



A group or number of people living within a specified area or sharing similar characteristics (such as occupation or age). (Source: ATSDR Glossary of Terms  )


Pregnancy outcomes

Results of conception and ensuing pregnancy, such as sex ratio, birth weight, spontaneous abortion, congenital malformations, lower birth weight, preterm delivery or stillbirth. (Source: GreenFacts)


Large group of unicellular animals which are bigger and more complex than bacteria.

Undetectable to naked eyes, most of them are around 0.01-0.05 mm. Examples include amoebas and flagellates.

Protozoa can cause diseases such as malaria and sleeping sickness.

Untreated water may be contaminated with protozoa some of which may not be killed by disinfection alone. (Source: GreenFacts)


The probability that something will cause injury or harm. (Source: ATSDR Glossary of Terms  )

Route of exposure

The way people [or other living organisms] 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]. (Source: ATSDR Glossary of Terms  )

Scientific Consensus

The Scientific Consensus represents the position generally agreed upon at a given time by most scientists specialized in a given field. (Source: GreenFacts)


Sedimentary rock(s)

Rocks consisting of cemented material worn away from pre-existing rock, which have been deposited in layers, by water or by air. (Source: GreenFacts )


Sewage refers to waste-water from homes and industry which is collected and carried away in sewers (pipes or tunnels). When raw waste-water is cleaned in treatment plants the waste product is sewage sludge, which can be used as a fertiliser under certain conditions or deposited in landfills. (Source: GreenFacts )


A type of soft sedimentary rock, formed by the deposition of successive layers of fine particles (such as clay, silt or mud) carried mainly by water. (Source: GreenFacts )

Sodium perborate

Sodium perborate is a white odorless crystalline compound soluble in water. Its chemical formula is NaBO3. (Source: GreenFacts)



A substance is soluble if it dissolves in certain fluids. The fluid [gas or liquid] (present in excess) is called the solvent and the substance dissolved in it is called the solute which together form a solution. The process of dissolving is called solvation. A solution that can not hold any more solute is said to be saturated. (Source: GreenFacts )

Surface water

Water on the surface of the Earth, such as in lakes, rivers, streams, ponds, and springs. (Source: ATSDR Glossary of Terms   )


A group of cells joined to perform a set of functions. (Source: GreenFacts)

Tolerable Daily Intake

A TDI is an estimate of the amount of a substance in air, food or drinking water that can be taken in daily over a lifetime without appreciable health risk. TDIs are calculated on the basis of laboratory toxicity data to which uncertainty factors are applied.

TDIs are used for substances that do not have a reason to be found in food (as opposed to substances that do, such as additives, pesticide residues or veterinary drugs in foods- see ADI). (Source: GreenFacts)



Able to poison or harm an organism. Toxic substances can cause adverse health effects. (Source: GreenFacts)


The capacity or property of a substance to cause adverse effects. (Source: GreenFacts)



The study of the harmful effects of substances on humans or animals. (Source: ATSDR Glossary of Terms  )

UK Food Standards Agency

"The Food Standards Agency is an independent food safety watchdog set up by an Act of Parliament in 2000 to protect the public's health and consumer interests in relation to food.

Between 2001 and 2006, the Agency's key aims are to:

  • reduce foodborne illness by 20% by improving food safety right through the food chain.
  • help people to eat more healthily.
  • promote honest and informative labelling to help consumers.
  • promote best practice within the food industry.
  • improve the enforcement of food law.
  • earn people's trust by what we do and how we do it."

A white or gray to colorless borate mineral, formed when boron rich water evaporates in arid climate. It is found in some arid regions of California and Nevada, USA; Tarapaca, Chile and Kazakhstan. (Source: GreenFacts)

University of Leeds

"The University of Leeds came into being in 1904 but its origins go back to the nineteenth century with the founding, first, of the Leeds School of Medicine in 1831 and then the Yorkshire College of Science in 1874. (...)"

"The University of Leeds is acclaimed world-wide for the quality of its teaching and research. (...)" (Source: ULEEDS website )

US Environment Protection Agency

The Environment Protection Agency's of the USA was founded in 1970. It's "mission is to protect human health and to safeguard the natural environment — air, water, and land — upon which life depends."

The EPA enforces federal environmental protection laws. It registers and regulates pesticides, enforces laws covering outdoor air and drinking water quality and regulates the disposal of hazardous and solid wastes.

It has now grown into a big and powerful administration: "18,000 people in Headquarters program offices, 10 regional offices, and 17 labs across the country, EPA employs a highly educated, technically trained staff, more than half of whom are engineers, scientists, and environmental protection specialists. A large number of employees are legal, public affairs, financial, and computer specialists."

U.S. EPA's scientific publications are widely recognized as reference materials. (Source: US EPA website  )

Wet Weight

The plant, animal, or other material containing the chemical of interest is not dried to remove water. The amount of the chemical found in subsequent analysis is expressed as the weight of chemical divided by the total weight, including any water present, of the material which once contained it. (Source: GreenFacts)

World Health Organization

"The World Health Organization  (WHO) is the directing and coordinating authority on international health within the United Nations’ system. WHO experts produce health guidelines and standards, and help countries to address public health issues. WHO also supports and promotes health research. Through WHO, governments can jointly tackle global health problems and improve people’s well-being.

193 countries and two associate members are WHO’s membership. They meet every year at the World Health Assembly in Geneva to set policy for the Organization, approve the Organization’s budget, and every five years, to appoint the Director-General. Their work is supported by the 34-member Executive Board, which is elected by the Health Assembly. Six regional committees focus on health matters of a regional nature."

WHO's scientific publications are widely recognized as a reference source.

The WHO has a number of regional offices which address the specific issues of those regions.

WHO World Regional Offices
  WHO African Region  (46 countries)
  WHO European Region  (53 countries)
  WHO Eastern Mediterranean Region  (21 countries)
  WHO Region of the Americas  (35 countries)
  WHO South-East Asia Region  (11 countries)
  WHO Western Pacific Region  (27 countries)

Other articles you might like...
Epidemic diseases home
Key steps taken by the WHO in 2019 to strengthen regional and national capacity to detect, verify and control emerging infectious diseases.
Aspirin & Cancer home
Various extracts on aspirin from the World Cancer Report 2020 indicate that aspirin may have important preventive effects on various forms of cancer, which are highlighted here.
Cancer home
What are the strategies that can be used for cancer prevention and early detection?
A-Z List
    Themes covered
    Publications A-Z

    Get involved!

    This summary is free and ad-free, as is all of our content. You can help us remain free and independant as well as to develop new ways to communicate science by becoming a Patron!