The impossible water sensor

This year, there is a question hanging over Europe’s rivers, lakes and seas. The EU Water Framework Directive, a water management plan adopted in 2000, requires that all surface water be of ‘good status’ by the end of 2015. But how will the member states know whether they have met that objective? Checking the health of Europe’s many water bodies entails understanding the levels of at least 500 chemicals. And analytical chemist Dermot Diamond says the EU has a problem there.

The only way to measure the levels of those 500 or so chemicals accurately is with a tandem liquid chromatography–mass spectrometry instrument (LCMS). But the use of such instruments is unlikely to be feasible on a Europe-wide scale. It would take multiple batteries of LCMS machines, plus staff and laboratories that meticulously keep track of their samples (to avoid accusations of fraud). That’s not feasible, says Dermot, if only because each LCMS machine costs around £500,000.

The answer, he says, is likely to be remote sensors installed in water bodies that sit there quietly measuring chemical levels and broadcasting the data back to Europe’s laboratories. The trouble is, sensors that fit this brief do not yet exist.

So chemists are beginning to ask what it would take to build a sensor that could be thrown into a lake or river, where it would sit for years, without harming the environment, remotely reporting chemical concentrations to a central hub. Meanwhile, big research funders are also beginning to recognise the pressing need for these sensors. 

Josh Howgego discusses Dermot's research, which may hold the key.