Are we too clean for our own good?
Written by Eloise Dortch - 30 March 2009
Consumers may think they are keeping the family safe by using antibacterial cleaners, but scientists are now warning that they may be breeding a new generation of superbugs and introducing carcinogens into the food chain.
Antibacterial products include soaps, household cleaners, toothpastes, children's toys, mops and wipes. But the chemical villains in many of them-triclosan and triclocarban-remain active in the environment for years and could pose a significant health risk.
Experts worry that widespread use of them may help turn some dangerous germs into superbugs resistant to antibiotics.
Antibacterials, or biocides, are non-specific. That means they kill weak bacteria, encouraging resistant bacteria to grow and take over the population, according to Royal Perth Hospital's head of microbiology and infectious diseases, Kerryn Christiansen.
But she warned it was not necessary to kill bacteria unless there was an infection or a wound prone to infection. For general use around the home, it was better simply to use detergents, which removed dirt. "Its overkill", Dr Christiansen said. "Just detergent is the way to go".
The second concern has particular relevance to WA, where there are plans to recycle sewage to boost groundwater supplies.
Tonnes of chemicals in antibacterial soaps used in bathrooms and kitchens are being released into the US environment but recent research by Johns Hopkins University there has found triclosan and triclocarban survive being flushed down household drains and sewage treatment plants - and remain active months or years later in sewage sludge spread on farms.
Triclocarban, found in 60 per cent of US streams, is suspected to be carcinogenic, while triclosan-which has been detected in breast milk in Europe-is known to become carcinogenic under certain conditions.
Johns Hopkins environmental health scientist Rolf Halden has used his finds to urge US authorities to monitor soil, ground water and crops fertilised with treated sewage-and the food made from them – for the chemicals.
In WA, sewage sludge is also used to fertilise cereal crops and there are no checks for triclosan and triclocarban.
Water Corporation water technologies general manager Keith Cadee said there was no evidence of any adverse effect occurring because of chemicals in WA sewage sludge or waste water.
"We will do our best to remove contaminants, but if these ones are persistent and can't be removed in the normal treatment process, then we expect the regulators to ensure they aren't put on the market", he said.
Health Department communicable diseases director Paul Van Buynder said that as a result of the US study, triclosan and triclocarban would be added to a list of 400 contaminants authorities would look for in sewage and sewage products.
A three-year project begun six months ago by the Health Department, Water Corporation, CSIRO, Curtin University, University of WA, and the Chemistry Centre planned to produce a comprehensive picture of contaminants in WA's waste water.