No Observed Adverse Effect Level

{
  "id": "MLC-T-ENV-018702",
  "term": "No Observed Adverse Effect Level",
  "field": "Environment",
  "definitions": [
    "1. A level of exposure which does not cause observable harm.\n\n2. The highest dose in a toxicity study which does not result in adverse health effects.\n\n3. An exposure level at which there are no statistically or biologically significant increases in the frequency or severity of adverse effects between the exposed population and its appropriate control; some effects may be produced at this level, but they are not considered as adverse or precursors to adverse effects. In an experiment with several NOAELs, the regulatory focus is primarily on the highest one, leading to the common usage of the term NOAEL as the highest exposure without adverse effect. See also: LOAEL.",
    "1. The highest level of a stressor evaluated in a toxicity test or biological field survey that causes no statistically significant difference in effect compared with the controls or a reference site.\n\n2. The highest exposure level at which there are no biologically significant increases in the frequency or severity of adverse effect between the exposed population and its appropriate control; some effects may be produced at this level, but they are not considered adverse or precursors of adverse effects.\n\n3. The highest dose in an experiment which did not produce an observable adverse effect.\n\n4. An highest exposure level at which there are no statistically or biologically significant increases in the frequency or severity of adverse effect between the exposed population and its appropriate control; some effects may be produced at this level, but they are not considered adverse, nor precursors to adverse effects.\n\n5. An exposure level at which there are no statistically or biologically significant increases in the frequency or severity of adverse effects between the exposed population and its appropriate control; some effects may be produced at this level, but they are not considered as adverse, or as precursors to adverse effects. In an experiment with several NOAELs, the regulatory focus is primarily on the highest one, leading to the common usage of the term NOAEL as the highest exposure without adverse effects.\n\n6. The highest tested dose of a substance that has been reported to have no harmful (adverse) health effects on people or animals.\n\n7. The highest exposure (or dose) level of a chemical at which there are no statistically or biologically significant increases in frequency or severity of adverse effects seen between the exposed population and its appropriate control; some effects may be produced at this level, but they are not considered to be adverse (or precursors to adverse effects, when used in deriving reference values). See A Review of the Reference Dose and Reference Concentration Processes (EPA, 2002).",
    "The highest exposure level at which there are no biologically significant increases in the frequency or severity of adverse effect between the exposed population and its appropriate control; some effects may be produced at this level, but they are not considered adverse or precursors of adverse effects."
  ],
  "abbreviation": "NOAEL",
  "synonyms": [
    "NOEL"
  ],
  "subject": [
    "Chemicals, toxics and pesticides",
    "Health and safety"
  ],
  "see_also": [
    "No Observed Effect Level"
  ],
  "references": [
    "Environmental Issues Terms & Acronyms; Pesticides Glossary",
    "Pesticides Glossary",
    "Benchmark Dose Software (BMDS) Glossary of Terms",
    "Waste and Cleanup Risk Assessment Glossary",
    "Integrated Risk Information System (IRIS) Glossary; Risk Assessment Glossary; EPA 2003",
    "Drinking Water Technical & Legal Terms",
    "EPA 2004",
    "EPA 2005b",
    "ATSDR 2004",
    "Health Effects Notebook Glossary",
    "Exposure Factors Handbook: Glossary"
  ],
  "url": "https://mlchart.com/terminology/environment/no-observed-adverse-effect-level/"
}