Access to clean drinking water is a crucial issue for many people living in developing countries. Testing water for pollution usually involves collecting samples and taking them back to a lab. More high tech solutions include mass spectrometry -- a very sensitive process that requires expensive specialist equipment -- to detect toxins in water supplies, but that can't be used for routine water monitoring and is too expensive and complex for using in developing areas.
Looking to find a better solution, researchers at the University of Bath along with the Bristol Robotics Laboratory at the University of the West of England have designed an inexpensive sensor using 3D printing that is powered by bacteria and can be placed directly in rivers and lakes to continually monitor water quality.
The University of Bath explains, "The sensor contains bacteria that produce a small measurable electric current as they feed and grow. The researchers found that when the bacteria are disturbed by coming into contact with toxins in the water, the electric current drops, alerting to the presence of pollutants in the water."“We found that when we injected a pollutant into the water there was an immediate drop in the electric current they produced. The drop was proportional to the amount of toxin present and the current is recovered once the toxin levels fell," said Dr. Mirella Di Lorenzo, Professor of Chemical Engineering at Bath.
That means that pollution levels can be monitored in real time without any more special equipment or experts needed for analysis.
The device is able to detect even very small quantities of pollutants. In testing, the researchers detected tiny concentrations of cadmium at quantities far below accepted safe levels.