Climate & Environment
Toxicity
Definition
Toxicity is the inherent capacity of a substance to cause adverse effects in living organisms, characterised by the dose-response relationship: the founding insight of toxicology (Paracelsus) is that the dose makes the poison. Effects are classified by route and timing — acute or chronic, target organ (neurotoxicity, hepatotoxicity), carcinogenicity, reproductive and developmental toxicity — and by environmental compartment (aquatic toxicity), with standardised tests generating the values (LD50, NOAEL) used in risk assessment.
References
This reference provides supporting context for how “Toxicity” is defined and used.
Source imported for editorial provenance.
Overview
How it is used
The concept structures hazard classification (GHS), occupational exposure limits, product safety assessment, pesticides regulation and green chemistry screening.
Why it matters
Every chemical decision — what to make, use, allow — is a toxicity decision; the concept is the unit of account of chemical safety.