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Dishwasher detergent chemicals entering UK drinking water, says Brunel study


Chemicals used in dishwasher detergents as 'silver polishing' agents have been found in UK drinking water – up to ten times above the levels recommended in Australia's guidelines for water reuse – according to research by Brunel University.

The study, published today [4 April] in the US journal Environmental Science & Technology, reveals that the use of the chemicals benzotriazole and tolytriazole in dishwasher tablets and powders may account for a significant proportion of inputs to wastewaters in the UK.

"From dishwasher to tap? Xenobiotic substances benzotriazole and tolytriazole in the environment" is the work of Brunel University’s Institute for the Environment, the Centre for Ecology and Hydrology, and WatStech Ltd.

The researchers took water and effluent samples from the River Erewash near Nottingham, and from the River Colne near Uxbridge, West London, which all contained the chemicals.  

Tap water samples were then also taken, and benzotriazole and tolytriazole were detected in all 80 samples analysed.

Lead researcher Dr Mark Scrimshaw from Brunel University explained that because these chemicals are water soluble and not easy to degrade, they enter rivers via wastewater and ultimately make their way into tap water.

"Although the presence of chemicals in the environment and drinking water does not in itself pose a threat to public health and the environment, there is some concern that the possible effects of long-term exposure to individual chemicals or mixtures of chemicals are not fully understood," Dr Scrimshaw said.

"The implications of our findings depend to a large extent on the degree of toxicity of benzotriazole and tolytriazole – but there are definitely gaps in scientific knowledge about being exposed to these chemicals. The lack of a complete set of good quality (eco) toxicological data on possible chronic effects of these high-use chemicals should caution against using them in a manner which may have contributed to such widespread environmental contamination," he added.

The study was funded by the Engineering and Physical Sciences Research Council.

Dr Scrimshaw is also Director of Brunel University’s Collaborative Research Network in Energy and Environmental Sustainability. He has routinely worked with the UK water industry on the approaches for removing chemicals which enter wastewater treatment works and controlling their discharge into the environment.



To interview Dr Mark Scrimshaw please call Phil Smith on 01727 733888 or email


Environmental Science & Technology (ES&T) is an authoritative source of information for professionals in a wide range of environmental disciplines. The journal, published by the American Chemical Society, combines magazine and research sections and is published both in print and online.