New paper test can identify contaminated water

London: Scientists have developed a simple, paper-based device that can be used to test if a water sample is contaminated, providing a low-cost way for developing countries to limit the spread of water-borne diseases.

Inspired by the simplicity of litmus paper - commonly used for the rapid assessment of acidity in water - the device consists of a microbial fuel cell (MFC), obtained by screen printing biodegradable carbon electrodes onto a single piece of paper.

An MFC is a device that uses the natural biological processes of 'electric' bacteria – attached to the carbon electrodes – to generate an electric signal.

When these bacteria are exposed to polluted water, a change in the electric signal occurs, which can be used as a warning message that the water is unsafe to drink.

Researchers from the University of Bath in the UK are now investigating how to link up the sensor with an electronic device such as a mobile phone, via a wireless transmitter, for a quick and user-friendly way of identifying if a water supply is safe to use.

The device has the potential not only to make water assessment rapid and cheap – each device is expected to cost no more than USD 1 – but it is also environmentally friendly since the paper sensor is made of biodegradable components.

The device is also easy-to-use and transport, weighing less than one gramme.

"This work could lead to a revolutionary way of testing water at the point of use, which is not only green, easy to operate and rapid, but also affordable to all," said Mirella Di Lorenzo, senior lecturer at the University of Bath.

"This type of research will have a significant positive impact, especially benefiting those areas where access to even basic analytic tools is prohibitive," said Di Lorenzo, lead author of the study published in the journal Biosensors and Bioelectronics.

"This device is a small step in helping the world realise the United Nations call to ensure access to safe drinking water and sanitation as a human right," he said.