What’s causing feminisation of fish in rivers and streams? What are the implications to human health?

Humans most vulnerable because one of the longest lived animals. Affect the early stage. Children most at risk because use a lot of plastics and they are closer to the ground and chew/eat things they really shouldn’t be eating.


Some of the more commonly studied effects of endocrine disrupting chemicals (EDCs) include:

  • Oestrogenic effects.
  • Anti-oestrogenic effects.
  • Androgenic effects.
  • Anti-androgenic effects.


What effects are already showing up in humans? According to Dr Handlinger at last week’s AAPSP Workshop, she reported that:

  • up to 40% of young men in some EU countries have low semen quality, reducing their ability to father children.
  • there is increased incidence of genital malformations such as cryptorchidism (non-descending testes) and hypospadias (penile malformations) in baby boys.
  • there has been an increase in adverse pregnancy outcomes such as pre-term birth and low birth weight.
  • neurobehavioural disorders associated with thyroid disruption affecting a high proportion of children in some countries.
  • increased global rates of endocrine-related cancers (e.g. breast cancer, endometrial, ovarian, prostate, testicular and thyroid cancers) in the last 40-50 years,
  • there are concerns that it is linked to increased prevalence of obesity and type 2 diabetes.


There is increasing evidence of adverse effects on wildlife. The 2013 EU response motions summarises the evidence:

  • “… significant… evidence that hormone-related disorders in wildlife including reproductive abnormalities, masulinisation of gastropods, feminisation of fish or decline of many mollusc populations in various parts of the word, are linked to the impact of chemicals with endocrine-disrupting properties”
  • Seal colonies in heavily polluted areas of the Baltic and North Seas – female reproductive pathologies and failure, bone damage – correlate with exposure to persistent organic pollutants (POPs), especially PCBs. Populations are recovering as PCB exposure decline.
  • Many amphibians are highly threatened with extinction – indications of an involvement of endocrine disruptors.
  • Especially in the UK, male fish have been widely affected by increased levels of egg yolk protein vitellogenin and by intersex. This is attributed to exposure to sewage effluents with contain oestrogenic and anti-androgenic chemicals.


If you notice, a lot of these problems are being encountered in mostly aquatic animals. Thus fish and amphibia are a major biological indicator, and tool. Globally, there has been a failure to adequately address the underlying environmental causes of trends in endocrine diseases and disorders. Close to 800 chemicals are known or suspected to be capable of interfering with hormone receptors, hormone synthesis or hormone conversion. However, only a small fraction of these chemicals have been investigated in tests capable of identifying overt endocrine effects in intact organisms. This is a major issue that has to be tackled by veterinarians, the medical profession and scientists, together.


From the EU paper, “endocrine disruptors are all around us in our everyday lives. They are present in food packaging, skin care products, cosmetics, building materials, electronic goods, furniture and floorings. Many products made of plastic in our homes and at our workplaces contain one or more types of chemicals which are suspected of having an endocrine-disrupting effect. As an individual consumer, it is impossible to know what substances are present in what products, particularly in the case of goods with no list of contents… endocrine disruptors are released from materials and products and accumulate, for example, in dust in our homes. Consequently small children, who crawl on the floor and also like putting things in their mouths, are at special risk of exposure.” (European Parliament 28.1.2013).


More information can be found about this topic at this link.





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