Optical sensors tackle river pollution across Europe

Minute amounts of organic pollutants-including oestrone-can now be detected in river water as a result of a new optical sensing instrument realised in a project funded by the EU's Environment Programme.

Pollution in water sources has been identified as a major source of environmental hazard, most recently associated with gender changes in fish, and implicated in falling levels of male fertility. Monitoring water quality and identifying pollution sources is therefore crucially important in river management.

Across the EU, methods of water monitoring need to be developed and implemented to ensure effective standardized enforcement of EU water quality directives. With partners in the UK, Germany, Spain, and the Slovak Republic, the EU-funded AWACSS (Automated Water Analyser Computer Supported System) project has developed a cost-effective online water-monitoring instrument that will help meet the needs of water managers.

The new instrument has drawn on the skills of research scientists and environmentalists and has been successfully demonstrated in river waters. It is designed for networking across Europe, and further developments are expected to enable early detection and warning.

The system uses optical sensors to enable rapid, simultaneous and high-sensitivity fluorescence detection of up to 32 organic pollutants and pesticides in river water. Amongst the pollutants to be successfully detected is oestrone, which occurs naturally and as a by-product of the contraceptive pill.

"Optical sensors have great potential in simultaneous, rapid, high-sensitivity measurement of multiple pollutants in water," said Professor James Wilkinson of the Optoelectronics Research Centre at the University of Southampton.

"The biosensor chip enables us to measure a large number of low molecular weight organic pollutants, and we have successfully detected levels at below 1 nanogram per litre for oestrone, which is one hundred times better than the original project target.

"Ultimately the instrument will be networked so that pollution sources can be monitored remotely with full automation," he continued, "and trend analysis and early-warning capabilities will be provided."

It is envisaged that the network will be distributed over a water catchment area, allowing a source of pollution to be localized early and characterized rapidly. In cases of severe water pollution, precautionary systems will be activated automatically or manually by operators of wastewater treatment plants.