Chemicals in household products approved as “safe” individually can combine to produce a toxic effect that can double cancer risk say researchers.
Science has already established that arsenic and environmental oestrogens are carcinogenic, but studies have only tested a single chemical in a single test and concluded that on their own tiny amounts are safe.
Since people are exposed to a cocktail of chemicals on a daily basis, researchers wanted to find out the consequences of combining these compounds.
Human prostate cells were exposed over a six-month period to safe doses, recommended by the US Environmental Protection Agency (EPA), of arsenic, oestrogen, and a combination of the two.
The results of the research at Texas Tech University in the US showed that mixing arsenic and oestrogen together was almost twice as likely to increase prostate cancer risk.
“The findings could have an impact on health regulations regarding the ‘safe’ doses of these chemicals and others,” said lead researcher Kamaleshwar Singh in a statement.
Ninety per cent of cancers are caused by environmental factors and only 5 to 10 per cent of tumours are due to genetic and hereditary causes, according to Singh.
Singh and his team were interested in studying arsenic, a toxin present in cigarette smoke and common in well water in some areas of India, Mexico, and the United States. Although arsenic is banned in pesticides in agriculture in the US, residues are deposited in soil from copper sulfate fertilisers.
Other sources of arsenic include rice, non-organic chicken, and make-up. According to the Campaign for Safe Cosmetics, some top-brand eyeliners, eye-shadows, mascaras, and foundations can be contaminated with arsenic.
Previous studies link arsenic consumption to lung cancer risk.
Public Health England and the British Geological Survey recently conducted a study to investigate the presence of arsenic in private water supplies in Cornwall. Over 5 per cent of drinking water samples exceeded the safe limit of arsenic.
Synthetic oestrogen has also been a target for testing because of its ubiquitous presence.
Xenoestrogens or foreign oestrogens mimic the effects of natural oestrogen in the body, acting as hormone disrupters, and can cause cancerous tumours, birth defects, and other developmental disorders.
These oestrogen-like chemicals include bisphenol A (BPA), commonly used for plastic containers and food can liners; pesticides; food preservatives like butylated hydroxyanisole (BHA) and butylated hydroxytoluene (BHT) added to many foods to prevent fat spoilage; food dye; and formaldehyde used in making carpets, plywood, and some nail polishes.
Also, industrial chemicals – phthalates – are used in the manufacture of plastics and in fragrances in cleaning products and toiletries. The US Centres for Disease Control and Prevention found in 2002 that more than 70 per cent of 72 personal-care products tested contained phthalates and exposure is widespread.
Even moisturisers may contain oestrogenic compounds. A 2009 report in the Journal of Clinical Oncology found that rejuvenating skin creams often contain oestrogen.
Researchers at Breast Cancer and Environmental Risk Factors in New York believe that exposure to synthetic oestrogen may lead to breast cancer in women.
Health campaigners recommend limiting exposure to these hormone disruptors by consuming organic food, drinking filtered water, and using natural personal care and cleaning products.