project

Improved Monitoring for Microbiologically Safe Bathing Water

The information available to bathers, water managers and health services is currently inadequate for a satisfactory assessment of the microbiological risks of leisure bathing in surface waters. The current Dutch Bathing Water Directive requires monitoring using cultures. However, the long time required for analysis means that the organisations involved (such the safety regions, municipal health services, water authorities, environmental services and municipal authorities) lack the tools needed to conduct a sound evaluation of the microbiological risks affecting, for example, events in open waters. Faster monitoring technologies are being developed but they cannot yet be implemented adequately.

Technology

Faster monitoring methods such as mobile qPCR, Tecta and BACTcontrol can deliver analyses of microbiological water quality in a short period of time. This makes high-frequency monitoring possible, and peaks in faecal contaminants can be visualised in near real-time with BACTcontrol. Mobile qPCR and Tecta (which, like BACTcontrol, detect E.coli bacteria) can be used easily for monitoring in multiple locations and at any time to provide an estimate of how faecal contamination develops over time and space.

Challenge

The previous TKI project Rapid detection of faecal pollution in bathing water did not shed light on the match between monitoring with the faster technologies and the statutory culture methods for different types of waters. As a result, the health risks cannot yet be properly estimated in practice using the faster technologies. It is important to make the technologies, in addition to the pretreatment procedures, suitable for non-faecal microbiological pollutants such as toxic blue-green algae and Leptospira, or viruses such as norovirus. It is also necessary to determine which technological modifications will be required for more sensitive monitoring and for monitoring in salty seawater or brackish water. In addition to these technological innovations, it is unclear what the best monitoring strategy is for the faster methods. The aim of this TKI project relating to safe bathing is to open up this missing knowledge.

Solution

At designated bathing locations, during swimming events and at unregulated bathing locations, the project will look at how best to monitor E.coli as a faecal indicator during peak pollution periods. A direct comparison will be made with the statutory culture approach. The project will also look at how, with technological modifications, the alternative faecal indicators (such as Bacteroides) as well as non-faecal pollutants can be visualised using the faster approaches. Close collaboration with multiple health services will provide a link to health complaints.  In addition, the results of the project provide an opportunity to better understand the dynamics and nature of faecal contamination, allowing for improvements in identification and tackling the source of contamination. Above all, the faster technologies make it possible to inform bathers in time and accurately about the current risks, and bathing waters will not have to be closed off for unnecessarily long periods of time.