Spectroscopy expands quality of water information

‘Right now, incomplete or infrequent water quality data can give people an inaccurate picture of what’s happening – and making decisions based on inaccurate data can be risky,’ said Dr. François Birgand, an assistant professor of biological and agricultural engineering at NC State and co-author of a paper describing the work. ‘Our approach will help people get more detailed data more often, giving them the whole story and allowing them to make informed decisions.’

NCSU claim also that the technique will also allow researchers to develop more sophisticated models that address water quality questions. Researchers are, for example, using data they collected using the new technique to determine the extent to which fertilizer runoff contributes to water pollution in specific water bodies and the role of wetlands in mitigating the effect of the runoff.

The researchers used UV-Vis spectrometers, which measure the wavelengths of light absorbed by water to collect water quality data. These can collect data as often as every 15 seconds over long periods of time. This is far more frequent than is possible with conventional water sampling and lab analysis techniques. They are disadvantaged, however, in that they are designed to monitor only a handful of key water quality parameters such as nitrates, dissolved organic carbon and turbidity – or how clear the water is.