A new study from researchers at the Oak Ridge National Laboratory (ORNL) demonstrates that microalgae can be used as effective sentinels to detect contaminants in water supplies. The research, funded in part by the Department of Energy’s Office of Biological and Environmental Research, uses a flourometer that measures the flourescence signal of algae that grow naturally in the source water.
“Our key result is that despite real-world conditions that create challenges, free-living microalgae combined with ‘work-around’ strategies can be used as broad-spectrum automated biosensor systems for continuous monitoring of source drinking water” – Elias Greenbaum, ORNL
Researchers used water from Tennessee’s Clinch River for the study, and use the known characteristics of Photosystems I and II, which convert light energy into chemical energy, to detect any changes in the process of photosynthesis. Even low levels of toxins alter the fluorescence patterns within minutes.
“Recent advances in optoelectronics and portability make this a powerful technology for monitoring the in situ physiology of aquatic photosynthetic organisms such as green algae and cyanobacteria.”
The authors say that the technology can be used to report statistically reliable data for toxins such as agrochemicals and blood and nerve agents at EPA guideline levels. The researchers examined five different classes of chemical agents for the study: atrazine, paraquat, methyl parathion, Diuron, and potassium cyanide, all harmful to human health. The authors were able to detect Diuron, an agrochemical, at levels as low as 1 part per million (ppm), due to a 17% decline in the efficiency of the algae’s Photosystem II process.
“We have shown that microalgae in source drinking water can be used as broad-spectrum, robust sentinel sensors to detect relatively low concentrations of toxins. We have also shown that the microalgae do not need to be in an optimized state for this technology to be effective.” – Greenbaum
Other funding for the research came from BAE Systems and the Defense Advanced Research Projects Agency (DARPA). The technology, under the name AquaSentinel, is in the process of being scaled up for commercialization.