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  • Glossary
| Last Updated:06/03/2017



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Occurring over a short time [compare with chronic].


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.

Acute exposure

Contact with a substance that occurs once or for only a short time (up to 14 days) [compare with intermediate duration exposure and chronic exposure].

Additive effect

A biologic response to exposure to multiple substances that equals the sum of responses of all the individual substances added together [compare with antagonistic effect and synergistic effect].

Adverse health effect

A change in body function or cell structure that might lead to disease or health problems


Requiring oxygen [compare with anaerobic].


Requiring the absence of oxygen [compare with aerobic].


A substance measured in the laboratory. A chemical for which a sample (such as water, air, or blood) is tested in a laboratory. For example, if the analyte is mercury, the laboratory test will determine the amount of mercury in the sample.

Analytic epidemiologic study

A study that evaluates the association between exposure to hazardous substances and disease by testing scientific hypotheses.

Antagonistic effect

A biologic response to exposure to multiple substances that is less than would be expected if the known effects of the individual substances were added together [compare with additive effect and synergistic effect].

Acrylic Acid

Originally used as a binder and film-former in dyes, adhesives and permanent-press fabrics.  Also used in skin creams and lotions.   Toxic by skin absorption.


Attributable risk

Difference between the risk of exhibiting a certain adverse effect in the presence of a substance and the same risk in the absence of the substance at risk



 Cell or organism with missing or extra chromosomes or parts of chromosomes and thus an abnormal number of chromosomes which is not an exact multiple of the haploid number.

Ames test

In vitro test for mutagenicity using mutant strains of the bacterium Salmonella typhimurium which cannot grow in a given histidine-deficient medium: mutagens can cause reverse mutations which enable the bacterium to grow on the medium. The test can be carried out in the presence of a given microsomal fraction (S-9) from rat liver (see microsome) to allow metabolic transformation of mutagen precursors to active derivatives.


One of several alternate forms of a gene which occur at the same relative position (locus) on homologous chromosomes and which become separated during meiosis and can be recombined following fusion of Gametes.


Substance produced by, and obtained from, certain living cells (especially bacteria, yeasts, and molds), or an equivalent synthetic substance, which is biostatic or biocidal at low concentrations to some other form of life, especially pathogenic or noxious organisms.


 Substance intended to kill birds.