New Test for Drinking Water Contamination

chemical analysis

Testing for a certain type of bacteria in drinking water could ensure it remains safe while reducing the occasional need to flush supplies and pipes with high concentrations of chlorine when levels of harmful bacteria rise too high, according to researchers from the United Kingdom.

The scientists found that a common form of bacteria, Methylobacterium, acts as an enabler in producing a biofilm that attracts harmful bacteria, such as Escherichia coli, that can be dangerous to human health, reports Space Daily. Biofilms are layers of bacteria that can coat the inner surfaces of drinking water pipes.

Lead researcher and professor Catherine Biggs, from the University of Sheffield’s Faculty of Engineering, explains:

Biofilms can form on all water pipes and as these are usually non-harmful bacteria, they don’t present a problem. However, biofilms can also be a safe place for harmful bacteria such as Escherichia coli or Legionella to hide. If the bacterial growth is too heavy, it can break off into the water flow, which at best can make water discoloured or taste unpleasant and at worst can release more dangerous bacteria. Our research looks at what conditions enable biofilms to grow, so we can find ways to control the bacteria in our water supply more effectively.

The team studied bacteria that are often found in Sheffield’s drinking water system to see whether combinations of them produced biofilms. Space Daily explains further how the research was conducted:

Funded by the Engineering and Physical Sciences Research Council, the research isolated four bacteria from water taken from a domestic tap: two were widely found in drinking water everywhere, one was less common and one was unique to Sheffield. The researchers mixed the bacteria in different combinations and found that, in isolation, none of them produced a biofilm. However, when any of the bacteria were combined with one of the common forms, called Methylobacterium, they formed a biofilm within 72 hours.

“Our findings show that this bacterium is acting as a bridge, enabling other bacteria to attach to surfaces and produce a biofilm and it’s likely that it’s not the only one that plays this role,” Biggs says. “This means it should be possible to control or even prevent the creation of biofilms in the water supply by targeting these particular bacteria, potentially reducing the need for high dosage chemical treatments.”

The findings could change the way municipalities target harmful bacteria in drinking water supplies. Currently, standard tests look for indicator organisms rather than the specific bacteria that cause contamination.

The Sheffield team is developing testing methods that identify specific bacteria using DNA analysis. “The way we currently maintain clean water supplies is a little like using antibiotics without knowing what infection we’re treating,” says Professor Biggs.

Traditional testing methods can be disruptive to the water supply, but the Sheffield team is offering a sophisticated analysis. Biggs says about current testing methods:

Although it’s effective, it requires extensive use of chemicals or can put water supplies out of use to consumers for a period of time. Current testing methods also take time to produce results, while the bacteria are cultured from the samples taken. The DNA testing we’re developing will provide a fast and more sophisticated alternative, allowing water companies to fine tune their responses to the exact bacteria they find in the water system.

Source: “Bacteria in drinking water are key to keeping it clean,” Space Daily, 8/23/13
Image by Alex Anlicker.