Man-made chemicals have been linked with illnesses such as testicular cancer and prostate cancer, which are both on the increase. Trends such as falling sperm counts and girls entering puberty earlier may also be due to the hundreds of chemicals we are exposed to in our daily lives. Of most concern are chemicals that can build up inside our bodies (so called 'bioaccumulative' chemicals) and chemicals that may be able to disturb our bodies' delicately balanced hormone systems (so called 'hormone disrupters'). There are even some chemicals which are known to do both of these things. This fact-sheet explains more about bioaccumulation and hormone disruption, and highlights some of the health problems that could be caused by the huge number of man-made chemicals in widespread use.

Bioaccumulative chemicals

Bioaccumulative chemicals are able to build up inside our bodies, often in our body fat. Some can also survive for long periods in the wider environment, and these are called 'persistent'. We are all carrying dozens of chemicals that were not in the bodies of our great-grandparents. Did you know that more than 300 man-made chemicals have now been detected in people?

In some cases scientists are not even sure where the chemicals come from. One particular chemical has been found in human fat, and in whales, grey seals and dolphins. Scientists know this chemical is bioaccumulative and hormone disrupting but are unsure of its source (although the chemical industry is by far the likeliest culprit).

Chemicals that accumulate in the body of pregnant women can also expose developing children in the womb. Man-made chemicals are even found in breast milk. (Please note, however, that Friends of the Earth shares the belief of the National Childbirth Trust, Europe's largest childbirth and parenting charity, and other experts, that breastfeeding is the most natural and healthy way to feed babies. The advantages to the immune system, growth and development of babies far outweigh the risks. A free information sheet on chemicals and breastfeeding, written in association with the NCT, is available from the address below).

Not all bioaccumulative or persistent chemicals are currently known to be toxic. However, if they are found to be so in the future they will already be contaminating our bodies and the environment. Friends of the Earth believes it is common sense to take the precaution now of phasing out all bioaccumulative or persistent chemicals.

PCBs - old chemicals that stick around

Examples of persistent and bioaccumulative chemicals include PCBs (polychlorinated biphenyls) - first produced by the chemical company Monsanto in 1929. They had a wide range of uses including in printing inks, paints and electrical transformers. They are extremely persistent and bioaccumulative, and were found in 1966 to be major environmental contaminants.

PCBs have been found in human fat and breast milk around the world, and even at the North and South Poles. PCBs are also hormone disrupters and have a range of other toxic effects, including suppression of the immune system. There is also strong evidence of the detrimental effects of PCBs on human intelligence. They are no longer produced in Europe, and in December 2000 a global treaty was signed to stop their production and to attempt to destroy as many PCBs as possible before they enter the environment.

This is one welcome victory against a dangerous chemical. But there are many other chemicals like PCBs in widespread use. Friends of the Earth believes a radical change in regulation is needed so that all risky chemicals

are replaced with safer alternatives.

Hormone disrupting chemicals

Our delicately balanced hormone system regulates much of our bodies. It governs, for example, the way children grow into adults, our sexual characteristics and our day-to-day bodily functions, such as the way our bodies burn oxygen to make energy and the way we digest food. Hormone disrupting chemicals are able to imitate or disrupt the action of these natural hormones. It is increasingly being discovered that more and more chemicals in everyday use are hormone disrupters.

Health concerns

There are grave concerns about a number of hormone-associated illnesses. Rates of testicular, breast and prostate cancers have all been rising in recent decades and sperm counts have been falling. No one knows exactly why but we do know that we are exposed to hundreds of hormone disrupting chemicals in our daily lives - many of which were not around a century ago. As the eminent Royal Society said in a recent report on the subject: "In reality, humans are exposed not to a single endocrine [hormone] disrupter but to a cocktail of such chemicals, and the possibility that such chemicals have additive or reinforcing effects has to be considered seriously...Despite the uncertainty, it is prudent to minimise exposure of humans, especially pregnant women, to [these chemicals] ...Regulations cannot be 'put on hold' until all the evidence has been collected.”
*     Low sperm counts in young Danes - Much research has been published indicating that sperm counts have reduced in the past 40-50 years. One of the most disturbing studies, published in 2000, looked at young men in Denmark who were starting military service. The authors said: “surprisingly low sperm counts were found in this population of 18-20 year old men.” The study concluded that more than 40 per cent of young Danish men have reduced sperm counts which is associated with decreased fertility.

*     Testicular cancer increasing - Testicular cancer increased in incidence by 55 per cent between 1979 and 1991 in England and Wales. It is believed to result from problems occurring during development of the testes whilst the individual is in the womb. Risky chemicals are thought to be a likely culprit.

*     A shortage of boys - The ratio of male to female births has fallen in the last 20-40 years in Denmark, the Netherlands, Sweden, Germany, Norway, Finland, Canada and the US. It is not clear why this is happening, though pollution and hormone disrupting chemicals have been suggested as possible causes.

*     Early puberty in girls - Scientists have found that nowadays one in six girls in Britain is starting to show signs of puberty at the age of eight, compared to one in 100 girls a century ago. No-one knows why, but it is very possible that hormone disrupting chemicals are at least partly to blame.

*     Breast cancer increasing - It is estimated that the incidence of breast cancer has increased by one per cent per year since the 1940s in the USA, and by 50 per cent in Denmark between 1945 and 1980. It has also increased in incidence in the UK over the last few decades. Research has once again suggested a link between breast cancer and exposure to hormone disrupting chemicals.

*     Prostate cancer increasing - Prostate cancer increased by 40 per cent between 1979 and 1991 in England and Wales. Although some of this increase may be due to improved diagnosis, hormone disrupting chemicals are a possible cause.

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