Helsingborg introduces laser testing of beach water purity

A truly pioneering innovation, that, together with the implementation of DNA sequencing of bacteria, can transform public health management

The Swedish city of Helsingborg has 15 bathing spots on its territory, and it already provides a beach water quality forecast online to residents. However, authorities have recommended that four of the beaches be avoided this summer because they have frequently shown elevated levels of intestinal bacteria through measurements over the past four years.

On the bright side, they have also announced a pilot project, which will boost the testing of the water quality in a pioneering way – the measurements are done with a laser. According to the city website, this makes Helsingborg the first municipality in the world to try this approach. If it is successful, the benefits can be far-reaching on a global scale.

Water purity testing has two obstacles, both time-related

The site of the pilot project is Pålsjöbaden beach. There, seawater is pumped up to three devices. Two of them measure intestinal bacteria (E. coli and enterococci). The third is a laser. By connecting the devices together, the laser must learn what water with bacteria looks like.

“Most of the time the pattern of bacteria looks the same, but after a downpour when the bacteria arrive, the pattern changes. When it rained a few weeks ago, it was exciting to look at the readings. It was excellent that they showed high values,” says Elisabet Lindberg, beach manager at the City of Helsingborg, speaking to the municipal press service.

If the pilot project is successful, it means completely new opportunities to warn of bad bathing water. The problem with water testing is that it takes a long time. The water analysis for the presence of bacteria takes three days.

The laser can also learn what bathing water looks like just before it goes bad. With measurement data, current data and data on radiation from the sun, the goal is for the data to come together in a reliable forecast. Then warnings can be made even before the bacteria reach the shores.

It is possible, thanks to DNA sequencing to also understand the origin of the bacteria. The problem though is that takes even longer. The water samples from last year are still awaiting analysis, for example. Nevertheless, it is an important tool to figure out the source of contamination and take the necessary measures.

And according to Elisabet Lindberg, many municipalities are already paying attention to that project, which increases hopes for the future of water purity control.