There are an estimated 70 000 to 80 000 synthetic chemicals in use globally today. Some are essential ingredients in numerous products, others are unintended by-products of manufacturing processes and many have become ubiquitous in the natural environment. While the majority may be innocuous, only a small fraction have ever been tested for safety and toxicity, while numerous others are known to have potentially detrimental health and environmental effects.
These chemicals find their way into the air, waters and plants and from there they tend to accumulate inside the bodies of animals with concentrations increasing towards the top of the food chain. They’ve been detected in people living in the remotest Arctic regions and scientists believe they explain, at least in part, rising disease rates in polar bears as well as high cancer occurrences in a range of species from Beluga whales and sea lions to humans.
There are agricultural chemicals and pesticides, some of which have recently been linked to an increased risk of Attention-Deficit/Hyperactivity Disorder, flame retardants in everything from cars to TV sets, phthalates in plastics, carcinogenic organochlorine compounds such as polychlorinated biphenyls, super-toxic dioxins and triclosan, an endocrine-disrupter known to interfere with the growth and development of tadpoles and an ingredient in toothpaste, anti-bacterial soap, face wash and moisturisers.
The history of one synthetic chemical, diethylstilbestrol (DES) is particularly instructive. From 1941, DES, a synthetic oestrogen, was approved and heavily marketed for use in hormone-replacement treatments for menopausal women and from the late 1940s it was also administered to millions of pregnant women, supposedly to prevent miscarriages. All of this even though animal studies had shown early on that DES was carcinogenic and caused intersex conditions and reproductive problems. Limited short-term tests on humans seemed to indicate that DES was safe. The drug was only withdrawn in 1971 after thousands of women who had been exposed to DES in their mother’s womb developed fertility and reproductive health problems and a variety of cancers in adolescence and adulthood.
Beginning in the 1950s DES was fed to livestock in the US after researchers found that chickens and cattle could be brought to market faster and more cost-effectively that way. Soon, 95% of all US cattle were on a DES-enhanced diet. Scientists also knew that these animals were excreting large quantities of powerful and potentially harmful synthetic estrogens into the environment. The use of the drug in beef cattle was only effectively banned in the US in 1979, while other hormones and steroids are still widely used in the industry today and routinely find their way into the environment and the food chain.
You’d think we’d have learnt from that lesson. Apparently not. There is currently an international debate about the potential health and environmental threat of bisphenol A (BPA), a chemical widely used in the production of plastics. It’s an ingredient in everything from water bottles and the linings of food cans to baby bottles. Leached from these plastics it finds its way pretty much everywhere. According to the US Centre for Disease Control, BPA is present in more than 90% of urine samples representative of the American population. An independent study found BPA in 46 out of 50 canned food samples from 19 US states and Ontario.
Scientists have known for almost 80 years that BPA is a synthetic oestrogen that behaves in a similar way to DES. Animal studies have shown that even at small concentration levels it leads to increased risks of cancer, diabetes, obesity, heart disease, infertility, developmental problems and reproductive disorders, while manufacturing and packaging companies claim it is safe.
An estimated ten million tons of toxic chemicals, some two million tons of them carcinogenic, are released into the environment worldwide every year. Blood tests show that many of these chemicals routinely make their way into our bodies. Will there be detrimental effects? Let’s talk again in 20 years.
- Andreas manages Lobby Books, the independent book shop at Idasa’s Cape Town Democracy Centre.
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