Environmental persistence

Environmental persistence is the length of time a chemical remains in air, water, soil, or organisms before it degrades or disperses. It depends on the chemical’s properties and the conditions of its surroundings.

Photolysis: Chemical decomposition caused by absorption of light, especially ultraviolet or visible radiation. Sunlight can rapidly degrade chemicals exposed at the atmosphere’s surface or in clear water.
Half-life: The time required for the amount or concentration of a substance to fall by half under specified conditions. Environmental half-lives provide a measurable estimate of how quickly chemicals disappear.
Bioaccumulation: The buildup of a substance in an organism when uptake exceeds elimination. A chemical can persist in the environment without accumulating in organisms, or accumulate despite environmental breakdown.
Persistent organic pollutants: Organic chemicals that resist degradation, persist in the environment, and can accumulate in organisms. This group is defined partly by resistance to environmental breakdown.
Hydrolysis: A chemical reaction in which water breaks one or more bonds in a molecule. Water-driven reactions can control the lifetime of chemicals in aquatic environments.
Persistence, bioaccumulation and toxicity: A chemical hazard assessment considering persistence, accumulation in organisms, and toxic effects. Persistence is assessed alongside bioaccumulation and toxicity in chemical regulation.
Biomagnification: The increase in a substance’s concentration in organisms at successively higher trophic levels. Food-web concentration is distinct from how long a chemical lasts outside organisms.
DDT: A synthetic insecticide whose environmental persistence and ecological effects led to widespread restrictions. Its residues can remain long after application and move through food webs.
Biodegradation: The breakdown of substances by living organisms, especially microorganisms. Microbial activity can transform persistent compounds, though rates vary across environments.
Stockholm Convention: A global treaty that restricts or eliminates persistent organic pollutants. The treaty uses persistence as one basis for controlling chemicals that travel and remain for long periods.

Linked from 14 pages