A WWF Journalists’ Briefing on Endocrine Disruptors
Substances which Disrupt the Hormone System

20 July 1998

"Endocrine disruptors", "oestrogen mimickers", "synthetic hormones”. Although known by a variety of names, these synthetic chemicals all interfere with naturally produced hormones.

Each year 1000 new synthetic chemicals enter the world market, most of them without adequate or appropriate testing.

Today, there are at least 300-500 measurable chemicals in people’s bodies that had not been found in anyone's tissue before the 1920s. There are more that we have no way of measuring. Even today chemists are unable to identify all the man made chemicals found in living tissue. Declining sperm counts, increased rates of breast, testicular and prostate cancer and increasing incidences of childhood hyperactivity and learning disorders are now being studied in the context of hormone disruption as behavioural and developmental effects have been shown.

As additives from plastics, detergents, pesticides and other industrial pollutants continue to be released on to land and into rivers and the oceans, WWF is calling for more research into their effects and for measures to eliminate substances so far identified as endocrine disruptors.

Although many chemicals have been tested for risk of skin and eye irritations, mutations, obvious birth defects and cancers, the tests have been inadequate to catch the ”invisible” endocrine disruptors, which affect the way an individual functions from a neuronal, behavioural, developmental or reproductive point of view. Chemicals that have been in use for many years have had even less testing.

Yet just a minute quantity of these synthetic chemicals can have a devastating effect on the endocrine system, particularly at critical times such as during pregnancy and foetal development.

Many chemicals with largely industrial origins, such as PCBs and dioxins, have built up in the food chain and can be found in meat, fish and dairy produce. But contamination of the human diet also occurs when other chemicals, such as phthalates, ”migrate” out of packaging materials into food. Phthalates have a tendency to accumulate in fatty tissue. When released into the wider environment they are absorbed into sediments and may not break down for a long time. WWF wants to see research into all potential endocrine disrupting chemicals to be prioritised, funded and coordinated, and the amount of phthalates released reduced, in line with the precautionary principle.

OSPAR must take immediate action to reduce and eliminate the new wave of EDCs released from land based, offshore and shipping sources. Whether banned, restricted or still in use, these substances are ending up as a harmful chemical cocktail in the marine environment where they pose unpredictable threats to marine wildlife.

Editors’ Notes:
Hormones are chemical messengers within a cell or organ. They are released into the bloodstream by the endocrine glands, which include the testicles, ovaries, pancreas, thyroid, the parathyroid, thymus and pituitary glands. Hormones operate at minute concentrations in the body and act as ”messengers” - or transmitters - to a gene. They guide the development of sexual organs and nervous and immune systems.

If the hormone system is working correctly, the right message is sent and received by a cell or gene. However, if something happens to damage the hormone system the wrong messages or no message at all may be sent to the cell. If this happens at a critical point in development - at the foetal stage for instance, there can be serious and lifelong consequences for the offspring.

- In Canada Beluga whales have been washed up with malignant tumours, abdominal masses, bladder cancers and ulcers of the stomach, mouth and intestines. More than half the females examined had breast tumours and infections that would have made it difficult, if not impossible, to nurse their young.

- UK, France and Denmark: Between the 1940s and 1980s the rate of testicular cancer trebled and human sperm counts dropped by almost 50 per cent.

- In the UK fish exposed to substances being discharged into rivers were becoming hermaphroditic with male fish manufacturing the female egg yolk protein - vitellogenin - as a response to discharges works that were acting like the feminising hormone oestrogen.

- Researchers working with North Sea seals correlated high concentrations of endocrine disrupting chemicals with immune system suppression and reproductive failure.


Hormone disrupting pesticides, (such as atrazine and linuron), are sometimes found in water supplies and residues of hormone disrupting pesticides (such as vinclozolin and endosulfan) can be found in fruit and vegetables from recent crop applications. Other persistent pesticides (such as dieldrin, lindane) can enter the human diet from environmental contamination building up in the food chain.

For further information concerning OSPAR contact Cherry Farrow +44 468 721170 or David Cowdrey +44 370 238068 (mobiles) or the WWF Press Office +44 1483 412383.