Contamination
Encyclopedia
Contamination is the presence of a minor and unwanted constituent (contaminant) in material
, physical body
, natural environment
, at a workplace, etc.
All chemicals contain some level of contamination. Contamination may be recognized or not and may become an issue if the contaminated chemical is mixed with other chemicals or mixtures and causes additional chemical reactions. The additional chemical reactions can sometimes be beneficial, in which case the label ‘contaminant’ is replaced with reactant or catalyst. If the additional reactions are detrimental, other terms are often applied such as toxin
, poison
or pollutant
depending on the chemistry involved. A major fraction of chemistry is involved with identifying, isolating, and studying contaminants.
See also Environmental monitoring
, Radiation monitoring
Material
Material is anything made of matter, constituted of one or more substances. Wood, cement, hydrogen, air and water are all examples of materials. Sometimes the term "material" is used more narrowly to refer to substances or components with certain physical properties that are used as inputs to...
, physical body
Physical body
In physics, a physical body or physical object is a collection of masses, taken to be one...
, natural environment
Natural environment
The natural environment encompasses all living and non-living things occurring naturally on Earth or some region thereof. It is an environment that encompasses the interaction of all living species....
, at a workplace, etc.
Specifics
"Contamination" also has more specific meanings in science:- In chemistryChemistryChemistry is the science of matter, especially its chemical reactions, but also its composition, structure and properties. Chemistry is concerned with atoms and their interactions with other atoms, and particularly with the properties of chemical bonds....
, the term usually describes a single constituent, but in specialized fields the term can also mean chemical mixtures, even up to the level of cellular materials.
All chemicals contain some level of contamination. Contamination may be recognized or not and may become an issue if the contaminated chemical is mixed with other chemicals or mixtures and causes additional chemical reactions. The additional chemical reactions can sometimes be beneficial, in which case the label ‘contaminant’ is replaced with reactant or catalyst. If the additional reactions are detrimental, other terms are often applied such as toxin
Toxin
A toxin is a poisonous substance produced within living cells or organisms; man-made substances created by artificial processes are thus excluded...
, poison
Poison
In the context of biology, poisons are substances that can cause disturbances to organisms, usually by chemical reaction or other activity on the molecular scale, when a sufficient quantity is absorbed by an organism....
or pollutant
Pollutant
A pollutant is a waste material that pollutes air, water or soil, and is the cause of pollution.Three factors determine the severity of a pollutant: its chemical nature, its concentration and its persistence. Some pollutants are biodegradable and therefore will not persist in the environment in the...
depending on the chemistry involved. A major fraction of chemistry is involved with identifying, isolating, and studying contaminants.
- In environmental chemistryEnvironmental chemistryEnvironmental chemistry is the scientific study of the chemical and biochemical phenomena that occur in natural places. It should not be confused with green chemistry, which seeks to reduce potential pollution at its source...
the term is in some cases is virtually equivalent to pollutionPollutionPollution is the introduction of contaminants into a natural environment that causes instability, disorder, harm or discomfort to the ecosystem i.e. physical systems or living organisms. Pollution can take the form of chemical substances or energy, such as noise, heat or light...
, where the main interest is the harm done on a large scale to humans or to organisms or environments that are important to humans.
- In radiation protection the radioactive contaminationRadioactive contaminationRadioactive contamination, also called radiological contamination, is radioactive substances on surfaces, or within solids, liquids or gases , where their presence is unintended or undesirable, or the process giving rise to their presence in such places...
is radioactive substances on surfaces, or within solids, liquids or gases (including the human body), where their presence is unintended or undesirable, or the process giving rise to their presence in such places,.
- Also used less formally to refer to a quantity, namely the activity on a surface (or on a unit area of a surface).
- Contamination does not include residual radioactive material remaining at a site after the completion of decommissioningNuclear decommissioningNuclear decommissioning is the dismantling of a nuclear power plant and decontamination of the site to a state no longer requiring protection from radiation for the general public...
. - The term radioactive contaminationRadioactive contaminationRadioactive contamination, also called radiological contamination, is radioactive substances on surfaces, or within solids, liquids or gases , where their presence is unintended or undesirable, or the process giving rise to their presence in such places...
may have a connotation that is not intended. - The term radioactive contaminationRadioactive contaminationRadioactive contamination, also called radiological contamination, is radioactive substances on surfaces, or within solids, liquids or gases , where their presence is unintended or undesirable, or the process giving rise to their presence in such places...
refers only to the presence of radioactivity, and gives no indication of the magnitude of the hazard involved.
See also Environmental monitoring
Environmental monitoring
Environmental monitoring describes the processes and activities that need to take place to characterise and monitor the quality of the environment...
, Radiation monitoring
Radiation monitoring
Radiation monitoring involves the measurement of radiation dose or radionuclide contamination for reasons related to the assessment or control of exposure to radiation or radioactive substances, and the interpretation of the results .-Environmental monitoring:...
- In food chemistryFood chemistryFood chemistry is the study of chemical processes and interactions of all biological and non-biological components of foods. The biological substances include such items as meat, poultry, lettuce, beer, and milk as examples...
and medicinal chemistryMedicinal chemistryMedicinal chemistry and pharmaceutical chemistry are disciplines at the intersection of chemistry, especially synthetic organic chemistry, and pharmacology and various other biological specialties, where it is involved with design, chemical synthesis and development for market of pharmaceutical...
, the term "contamination" is used to describe harmful intrusions, such as the presence of toxinToxinA toxin is a poisonous substance produced within living cells or organisms; man-made substances created by artificial processes are thus excluded...
s or pathogenPathogenA pathogen gignomai "I give birth to") or infectious agent — colloquially, a germ — is a microbe or microorganism such as a virus, bacterium, prion, or fungus that causes disease in its animal or plant host...
s in food or medicinal drugs. - In forensic science, a contaminant can be complex materials such as hair or skin particles arising from sources not related to the ongoing investigation.
- In the biological sciencesBiologyBiology is a natural science concerned with the study of life and living organisms, including their structure, function, growth, origin, evolution, distribution, and taxonomy. Biology is a vast subject containing many subdivisions, topics, and disciplines...
accidental introduction of "foreign" material ('contamination') can seriously distort the results of experiments where small samples are used. In cases where the contaminant is a living microorganism, it can often multiply and take over the experiment, especially cultures, and render them useless. - In geologyGeologyGeology is the science comprising the study of solid Earth, the rocks of which it is composed, and the processes by which it evolves. Geology gives insight into the history of the Earth, as it provides the primary evidence for plate tectonics, the evolutionary history of life, and past climates...
and especially geochemistryGeochemistryThe field of geochemistry involves study of the chemical composition of the Earth and other planets, chemical processes and reactions that govern the composition of rocks, water, and soils, and the cycles of matter and energy that transport the Earth's chemical components in time and space, and...
, it can have similar effects where even a few grains of "modern" dust can distort results of sophisticated experiments. - the term "contamination" is sometimes used to describe accidental transfers of organisms from one natural environment to another.
- it has even been used in the "Directed panspermia" hypothesis about the origin of life on Earth, which suggests that visiting aliens accidentally infected the planet with microbes from their own world.