Most tests to check water quality and the standards behind them have not been updated in decades, which means that the results may not actually be that accurate. Scientists from Lawrence Berkeley National Laboratory recently developed a highly accurate, DNA-based method to detect and distinguish sources of microbial contamination in water.
The study, led by Eric Dubinsky and Gary Andersen, microbial ecologists at Berkeley Lab, supported by co-author, Steven Butkus of the North Coast Regional Water Quality Control Board, and titled “Microbial source tracking in impaired watersheds using PhyloChip and machine-learning classification” was recently published in the journal Water Research.
The award-winning PhyloChip is a credit card-sized device that can detect the presence of in excess of 60,000 different species of bacteria and archaea. Results from tests done at the Russian River watershed in Northern California showed that the device identified potential health risks that the commonly used faecal indicator tests failed to detect but also found that some of the conventional tests flagged bacteria that were not a health-risk.
According to Dubinsky, “With the PhyloChip, in an overnight test we can get a full picture of the microorganisms in any given sample. Instead of targeting one organism, we’re essentially getting a fingerprint of the microbial community of potential sources in that sample. So it gives us a more comprehensive picture of what’s going on. It’s a novel way of going about source tracking.”
According to the team, when the current tests were developed way back in the 1970s, sewage was basically flowing into our waters, so the tests worked really well, but now things are far more complicated, and since then a reference library of the microbial communities that occur in different faecal matter has been developed, which led to the development of a new model.
Researchers are working closely with the U.S. Environmental Protection Agency (EPA), which is looking at new technologies for what it calls “next generation compliance.” The ultimate goal is to make a smaller version of the PhyloChip that can be used in any location and by non-experts.