Keeping an eye on river pollutants

An optical sensor, capable of detecting minute amounts of organic pollutants in river water, has been developed in an EU-funded project.

The bio-sensor chip, which can measure trace quantities of pollutants including hormones such as oestrone, was developed at the University of Southampton, with further work conducted by the University of Tubingen in Germany. Siemens is now hoping tocommercialise the technology.

The AWACSS (Automated Water Analyser Computer Supported System) uses antibodies designed to attach themselves to specific pollutants. Each antibody is tagged with a fluorescent molecule. In an automated process, river water flows into the device and mixes with the solution, allowing antibodies to bind with pollutant molecules.

This mixture is then directed across the surface of the sensor. Any antibodies not bound to a particular pollutant within the sample will bind to the surface of the sensor. A laser beam is then directed across the sensor, causing the molecules attached to it to fluoresce.

Consequently a high fluorescent signal indicates low pollutant levels in the sample, as few antibodies have attached themselves to the sensor, while a dull signal indicates high pollution levels.

Monitoring water quality and identifying pollution sources areimportant as rivers are a vital source of water for humanconsumption. Prof James Wilkinson of the OptoelectronicsResearch Centre at the University of Southampton said the sensors are designed to operate in a network, to allow pollution sources to be monitored remotely, making it possible to spot trends andprovide early warnings.

During the project, the team has built on previous research into the underlying technologies behind the system, by investigating the specific needs of the water companies when carrying out rivermonitoring. ‘In a sense, as a research-led university it starts to get to the point when we have done our bit. We have to turn it over to the industry because we should begin to move in slightly different directions,’ said Wilkinson.

He believes the technology could be adapted and used in medical applications, such as in the analysis of drugs and drug abuse, or possibly screening for diseases. Alternatively, the technology could be applied to detecting dangerous substances such as anthrax and sarin.