Contaminated water is a major source of toxic heavy metal exposure for animals and people. The metabolic stress response of E. coli is used to detect the presence of toxic metals in tap water and wastewater. Difficult to detect heavy metal ions are thereby converted to more easily detectable chemical signals. Credit: Regina Ragan/UCI
Key points:
- Researchers show E.coli can be used to detect heavy metal contamination in water.
- The new method is based on sensitive nanoparticle-based sensors and machine learning.
- The technique can be applied to work on water sources or supplies anywhere in the world.
Scientists at the University of California, Irvine have shown E.coli can do more than keep you sick in bed for days. In a new study, researchers demonstrated that the bacterium can detect heavy metal contamination in water.
According to the findings, E. coli demonstrated a biochemical response in the presence of metal ions, a slight change the researchers were able to observe with chemically assembled gold nanoparticle optical sensors. Through a machine learning analysis of the optical spectra of metabolites released in response to chromium and arsenic exposure, the scientists were able to detect metals in concentrations a billion times lower than those leading to cell death, while being able to deduce the heavy metal type and amount with higher than 96 percent accuracy.
The entire detection process only took 10 minutes. The researchers say the method can be used to spot metal toxins—including arsenic, cadmium, chromium, copper, lead and mercury—at levels orders of magnitude below regulatory limits to provide early warning of contamination.
“This new water monitoring method is highly sensitive, fast and versatile,” said co-author Regina Ragan, UCI professor of materials science and engineering. “It allowed the algorithms to determine if drinking water was within U.S. Environmental Protection Agency and World Health Organization recommend limits for each contaminant with greater than 96 percent accuracy and with 92 percent accuracy for treated wastewater.”
Additionally, since the method is algorithm-based, it can be easily adapted to work on water sources and supplies anywhere in the world.
“Access to safe water is necessary for the health of people and the planet,” said Ragan. “New technology that can be mass manufactured at low-cost is needed to monitor the introduction of an array of contaminants in the water supply as a critical part of the solution for water security in the face of pollution and climate change.”
Information provided by UCI.