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Have you ever heard of waterborne diseases like dysentery and cholera? Illnesses like these are spread by microorganisms in contaminated water and can be a real risk to human health. In 2019 the World Health Organization estimated that almost 500,000 people die each year from drinking contaminated water!
One of the most common possible contaminants is the bacteria E. coli. At present, the standard way to check if drinking water is free from this bacterium is to add water samples to a special liquid that promotes growth of E. coli. If there is any E. coli in the water sample it will grow in this liquid, and researchers can detect it. This process has been used for decades, but it takes time for the bacteria to grow, and the test only looks for E. coli. This means that it is possible other microorganisms could pass through the test undetected.
Did you know genomics tools can change the way drinking water is tested for contaminants though? Instead of taking water samples and adding them to the liquid that helps grow E. coli they could instead check these samples for something called environmental DNA (eDNA). All microorganisms have a genetic code like we do. Just as a crime scene investigator can determine who was at a crime scene using DNA, researchers can check the water for DNA from known microorganisms to see if the bacteria are present. Because we know what the DNA sequence of E. coli and other bacteria such as Salmonella or Giardia, we can check the drinking water to see if there is any DNA in there that matches the microorganisms that might make us sick, which will tell us if those bacteria are in the drinking water.
Checking for eDNA in our drinking water will allow researchers to detect microorganisms that could make us sick much more quickly. It will also allow them to check for many more microorganisms than the current testing method. It is hoped that using genomic testing as standard practice will help make our drinking water even safer here in Canada. The British Columbia Centre for Disease Control is currently working to develop water testing kits that can quickly and effectively test for dangerous microorganisms in our drinking water. This technology can also be used to check if wastewater contains any harmful microorganisms from human waste before being released into the environment, as well as track disease outbreaks! As genomics tools become more common place and cost effective, they will be able to revolutionize the way we monitor water.