Scientists in the US have developed a low-cost method to monitor groundwater pollutants in real time that provides early warning for contamination.
Sensors were used to track levels of tritium and uranium-238 in the groundwater at the Savannah River Site, a former nuclear weapons production site in South Carolina managed by the Department of Energy (DOE).
Scientists at the DOE’s Lawrence Berkeley National Laboratory and Savannah River National Laboratory found their technique provided reliable information about plume behaviour over the last 20 years.
Their method is expected to reduce the frequency of manual groundwater sampling and lab analysis and therefore cut the monitoring cost compared to conventional techniques, which involve taking water samples every year or every quarter and analysing them in the lab.
Haruko Wainwright, a Berkeley Lab researcher who led the study said: “If there are anomalies or an extreme event, you could miss the changes that might increase contaminant concentrations or potential health risk. Our methodology allows continuous monitoring in situ using proxy measurements so we can track plume movement in real time.
“Analysis of the autonomous in situ data can be rapidly analysed remotely using machine learning methods. It can act as an early warning system – we can detect sudden changes in contaminant levels. These changes may indicate a need for more or less intervention in terms of the remediation strategy, ideally leading to improved as well as more cost-effective cleanup.”
She adds environmental monitoring has become more important in recent years as remediation methods have been shifting away from intensive groundwater treatment and soil removal.
Ms Wainwright said: “Intensive cleanup has a lot of negative environmental impacts, including air pollution, large energy-water use, and waste production. So experts have started thinking about a paradigm shift from this very intensive remediation to a more sustainable remediation – or ‘green remediation’ – so we don’t just think at the contaminant level but we think about the net environmental impact.”