- remain intact for exceptionally long periods of time (many
years); - become widely distributed throughout the environment
as a result of natural processes involving soil, water and, most
notably, air; - accumulate in the fatty tissue of living
organisms including humans, and are found at higher
concentrations at higher levels in the food chain; and - are
toxic to both humans and wildlife. As a result of releases to
the environment over the past several decades due especially to
human activities, POPs are now widely distributed over large
regions (including those where POPs have never been used) and,
in some cases, they are found around the globe. This extensive
contamination of environmental media and living organisms
includes many foodstuffs and has resulted in the sustained
exposure of many species, including humans, for periods of time
that span generations, resulting in both acute and chronic toxic
effects. In addition, POPs concentrate in living organisms
through another process called bioaccumulation.