Title: natural occurrence
Long Title: IUPAC Gold Book - natural occurrence
DOI: 10.1351/goldbook.15910
Status: current

Definition
Presence of a substance in nature, as distinct from presence resulting from inputs from human activities.

Note
The contamination of the natural environment by some man-made compounds may be so widespread that it is practically impossible to get access to biota with a truly natural level; only "normal" levels can be measured, those which are usually prevalent in places where there is no obvious local contamination.

Source
- PAC, 2007, 79, 1153. 'Glossary of terms used in toxicology, 2nd edition (IUPAC Recommendations 2007)' on page 1268 (https://doi.org/10.1351/pac200779071153)

Other Outputs
- html: https://goldbook.iupac.org/terms/view/15910/html
- json: https://goldbook.iupac.org/terms/view/15910/json
- xml: https://goldbook.iupac.org/terms/view/15910/xml

Citation: Citation: 'natural occurrence' in IUPAC Compendium of Chemical Terminology, 5th ed. International Union of Pure and Applied Chemistry; 2025. Online version 5.0.0, 2025. 10.1351/goldbook.15910
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Accessed: 2026-04-17T19:53:33+00:00