Wildlife and humans are exposed daily to these pervasive chemicals...

What are EDCs?

Endocrine Disrupting Chemicals (EDCs) are synthetic chemicals that interfere with naturally produced hormones, the body's chemical messengers, that control how an organism develops and functions.

Many manufactured chemicals mimic natural hormones and send false messages. Other synthetic compounds block the messages and prevent true messages from getting through.

Some cause disruption by preventing the synthesis of the body's own hormones or by accelerating their breakdown and excretion. Some EDCs are persistent in the environment and bioaccumulate; they accumulate in the fatty tissue of organisms and increase in concentration as they move up through the food web.

Why are EDCs a threat?
Wildlife and humans are exposed daily to these pervasive chemicals that have already caused numerous adverse effects in wildlife and are most likely affecting humans as well.

Hormones play a crucial role in the proper development of the growing fetus and EDCs can interfere with this development. The fetus is vulnerable even to the most minute concentrations of introduced substances. Substances that have no effect in an adult can become poisonous in the developing embryo.

Chemicals are passed from mother to offspring, via the womb and breastmilk in mammals and via the egg in reptiles, amphibians, fish and chickens, leading to "trans-generational" effects. Because of their persistence and mobility, they accumulate in and harm species far from their original source.

The effects of endocrine disruptors on animals are varied -- ranging from alligators born with abnormally small phalluses and birds with crossed beaks, to the sudden disappearance of entire populations. Wildlife researchers over the last few years have unearthed a variety of endocrine disruptor-related effects: interrupted sexual development; thyroid system disorders; inability to breed; reduced immune response; and abnormal mating and parenting behavior. Species such as terns, gulls, harbor seals, bald eagles, beluga whales, lake trout, alligators, turtles, and others, have suffered more than one of these effects.

Our current knowledge of endocrine disruption has been propelled by the evolving science surrounding this phenomenon. Scientific investigation has intensified over the last several years and has provided steadily growing evidence linking synthetic endocrine-disrupting compounds to impaired health in wildlife and humans.

To learn more , download WWF's Position Papers on Endocrine Disrupting Chemicals (DOC: 29.0 KB)

Bald Eagle (<i>Haliaeetus leucocephalus</i>) 
© WWF / Chris Martin Bahr
Bald Eagle (Haliaeetus leucocephalus)
© WWF / Chris Martin Bahr