Accumulation

POPs accumulate in the fatty portions of organisms--a term scientists call "biomagnification"--as they make their way through the food chain. Animals at the end of the food chain, such as birds and fish, tend to have the highest concentrations.

Example

In 1997, the Arctic Monitoring and Assessment Programme discovered that caribou in Northwest Canada had about 10 times more PCB (chemical used as a coolant) than their main food source: lichen. In that same area, the natural predator of the caribou--wolves--had concentrations of PCB 60 times that of lichen.

Types

The world produces most POPs for practical applications, but some, such as PCB, dioxin and furan, are produced indirectly through combustion and industrial production.

Effects

Contamination of an environment by POPs may lead to birth defects in animal species and neurological damage that induces strange behavior. Overall, wildlife levels decline in the presence of POPs.

Prevention/Solution

Representatives of 128 world governments signed the Stockholm Convention treaty in Stockholm, Sweden on May 23, 2001, to begin phasing out and eventually eliminating the use and production of POPs.

Source:

United Nations Environmental Programme: Persistent Organic Pollutants

US Environmental Protection Agency: Persistent Organic Pollutants: A Global Issue, A Global Response

World Bank: Stockholm Convention on Persistent Organic Pollutants (POPs)