POPs persist in the environment. They resist photolytic, chemical and biological degradation. They bioaccumulate in fatty tissues of living organisms. In the environment, their concentrations can magnify by factors of many thousands as POPs work their way up the food chain. POPs are widely distributed across the earth.
POPs are products and by-products of human industry that are of relatively recent origin.
In the early decades of this century, most POPs were virtually non-existent in our environment. My own personal concern about POPs began in the late 1980's when scientists and researchers discovered strong evidence of injury to fish, birds and mammals in or around the Great Lakes of North America. Alarmed by these findings, scientists and environmentalists began to investigate the possibility of similar injury to humans, who after all, can also be considered high predators. Diseases such as endometriosis, increased incidence of diabetes, and others. People are generally exposed to POPs through their food supply although workers and residents of communities near POPs sources can also be exposed through inhalation and dermal contact.