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Frogs at risk and possible implications for humans?

Why EU chemicals legislation needs updating to address chemical that damage the immune system highlights serious concerns for the health of frogs (amphibians) in the UK.Scientific research suggests that exposure to man-made chemicals in our environment may be playing an important role in disease because some chemicals can weaken the immune system  and increase susceptibility to infections and disease.There are likely to be implications for human health too.



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Cause for Concern

Ecosystems all over the world are now contaminated with a cocktail of man-made chemicals.

CHEM Trust is particularly worried about several potentially hazardous chemicals, especially those that are persistent, bioaccumulativ­e or those which can disrupt hormones. For a good summary see CHEM Trust’s report:

Effects of Pollutants on the Reproductive Health of Male Vertebrate Wildlife – Males Under Threat

A shortened version of this report is available in German

This report shows that male fish, amphibians, reptiles, birds and mammals have been harmed by chemicals in the environment. Widespread feminisation or de-masculinisation of male vertebrate wildlife is highlighted. These findings add to mounting worries about the role of hormone disrupting or so-called ‘gender-bending’ chemicals in the environment, and the implications for human health. boppic1



Otter Report:

Persistent organic pollutants and indicators of otter health: other factors at play? highlights serious concerns for the health of otters in the UK.Otters are one of our best loved species and research indicates that they may not be in the best of reproductive health. This raises the question as to whether modern chemicals, particularly endocrine disrupting chemicals (EDCs – hormone disruptors), could be to blame. ott_pic


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Research carried out on fish in many UK rivers show widespread feminisation. The male fish should have sperm in their testes but many have egg material there instead.

Persistent chemicals are those which don’t break down easily in the environment, and which can therefore last for decades. A chemical is said to ‘bioaccumulate’ if it builds up in our bodies or in wildlife.  Unfortunately, when a chemical is persistent and bioaccumulative (P&B) it may be passed from mother to baby via the egg, placenta or during suckling.

The hormone disrupting chemicals are very worrying because even at extremely low doses they can disrupt the normal workings of the reproductive, immune, nervous and other hormonally controlled systems. They can do this by mimicking natural hormones or blocking their action, or altering the breakdown or synthesis of the body’s own hormones.  Sometimes these chemicals are also called endocrine disrupting chemicals or EDCs for short, because it is the endocrine glands which secrete hormones.Some pesticides and flame retardants are persistent, bioaccumulative or hormone disrupting. Similarly, chemicals with these worrisome properties may be found in many consumer products including certain stain repellents, cosmetics, personal care products and plastics. allicrocs


There is a growing body of scientific evidence on the adverse impacts of several man-made chemicals on wildlife species.   Scientists have shown that many wildlife populations have already been affected by hormone disruptors.  The impacts include:

  • thyroid dysfunction in birds and fish
  • decreased fertility in birds, fish, shellfish and mammals
  • decreased hatching success in birds, fish and turtles
  • gross birth deformities in birds, fish and turtles
  • metabolic abnormalities in birds, fish and mammals
  • behavioural abnormalities in birds
  • de-masculinisation and feminisation of male fish, birds and mammals
  • de-feminisation and masculinisation of female fish and birds
  • and compromised immune systems in birds and mammals
  • The connection between effects in wildlife and the likely effects in humans are also being noted.
There is not one ocean or continent from the tropics to the once-pristine polar regions that is not contaminated with a toxic cocktail of many different man-made compounds.The pages in this section illustrate some examples of the known or suspected effects of chemical contaminants in wildlife. polarbearsnp