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Antibacterial products banned in the US – Expert Q&A

Posted in Briefings on September 6th, 2016.

A substance found in many antibacterial consumer products – like handsoaps and toothpaste – has been banned from some products in the United States because of its environmental effects.

Washing handsNew Zealand’s Environmental Protection Agency (EPA) last month accepted an application from the Green Party to consider grounds for reassessing triclosan.

The Science Media Centre asked two toxicologists about triclosan and whether New Zealand should follow suit and ban certain consumer products. Please feel free to use this Q&A in your reporting.

Dr Sally Gaw, senior lecturer, Department of Chemistry, University of Canterbury:

What do we know about triclosan’s efficacy in products like soaps and toothpastes?

“Triclosan is a broad-spectrum antibacterial agent. It is used in a wide range of consumer products including soaps, toothpaste, children’s toys, plastic wrap and sportswear. Soaps containing triclosan have been shown to be no more effective at controlling the spread of diseases in the home than soaps without triclosan.”

What do we know about the effects triclosan has in the environment?

“About 90 per cent of the triclosan used in soaps is washed off the body and enters the sewerage system. Triclosan is not fully removed in wastewater treatment plants and can be released into the environment either in wastewater discharges or in sewage sludge.

“Triclosan has been measured internationally in wastewater, waterways, sediments and aquatic organisms. In New Zealand, while there has been limited research, triclosan has been found in wastewater and seawater.

“Triclosan is toxic to bacteria, algae and fish. It has been shown to potentially affect aquatic food chains by altering the species of bacteria and algae living in streams. Triclosan can persist in sediments and can accumulate in organisms.

“Triclosan also has impacts on human health.  It can affect hormone function, damage the liver and kidneys and is a suspected carcinogen. Triclosan has been measured in blood, urine, amniotic fluid and breastmilk.

“Exposing microorganisms to triclosan and other antimicrobial compounds can trigger the development of antibiotic resistance in pathogenic bacteria. Antibiotic resistance is recognised as a global public health emergency.”

Is there reason to suggest any benefits are outweighed by harm caused in the environment?

“The evidence suggests that any benefits associated with using triclosan in consumer products are far outweighed by the impacts on human health and the environment. ”

Should New Zealand follow suit and consider banning products containing triclosan?

“Given that the research shows triclosan is harmful to human health and the environment and has minimal benefit in reducing disease transmission in the community, there is no reason to keep adding it to consumer products. I would strongly support New Zealand banning triclosan as an ingredient in consumer products including soaps, children’s toys and sportswear.”

Dr Louis Tremblay, environmental toxicologist, Cawthron Institute:

What do we know about triclosan’s efficacy in products like soaps and toothpastes?

“Triclosan is effective against a range of microbes. The key point to make here is that it requires to be in contact with the microbe for a minimum time. When washing hands or teeth, the amount of time the product is in contact with microbes is limited and it will not necessarily control them. ”

What do we know about the effects triclosan has in the environment?

“We know that it is found in the receiving environment and that the main source is sewage water. Some of the risk are linked to the fact that once triclosan is flushed down the drain, it retains its antimicrobial properties. In the first instance, it will enter the sewage treatment plant where the secondary biological treatment is based on the use of an active microbial community to degrade waste. Triclosan does reduce the efficacy of the treatment by killing some microbes.

“Another key risk is the potential development of resistance in the microbial communities. This mechanism is through the overexposure of microbial communities to triclosan and the selection of the resistant strains that can then transfer resistance to future generations of microbes. Triclosan also has some hormone disruption activity, which is another mechanism it can affect exposed organisms.”

Is there reason to suggest any benefits are outweighed by harm caused in the environment?

“Triclosan has broad-spectrum anti-microbial properties, that means that it is active to a range of microbes. That’s quite different to some of the antibiotic molecules that have a narrower target range.

“That makes triclosan a very good ‘weapon’ for uses like medical and veterinarian settings where there are potentially high concentrations of pathogens. Under those circumstances, it makes sense to use products containing triclosan to reduce the spread of disease vectors.”

Should New Zealand follow suit and consider banning products containing triclosan?

“I think this is an important step that New Zealand definitely needs to follow. However, it has to be done in a strategic manner as triclosan and other molecules remain an important weapon against nasty germs and should be used for the right purposes as described above. The ban also includes other products. I think that there is a need to continue to inform and educate the wider community about the reasons behind the ban.

“The chemical companies have invested huge effort and resources to market and sell those products and there is probably a perception that those products reduce the risk of sickness. It is important to know that good hygiene habits with hand washing and the use of a bar of soap reduce the risk to similar levels.

“It should be kept in mind that any liquid products such as liquid soap or shampoo do need to contain anti-microbial products to maintain their shelf life. It is about selecting the ones that are effective and will minimise potential environmental risk. This is where the wider community can play a role by choosing products such as bars of soap that do not contain as many of the additives such as colourant, musk etc.

“We need to remember that chemicals still play an important role to maintain our quality of life. However, we must use them in ways that maximise their intended objectives while minimising the risk to ourselves and our environment.”

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