How healthy will coastal areas of Europe remain with climate change?
Will swimming, surfing, or a day at the beach make us more likely to get sick in the future? Climate change affects so-called pathogens such as bacteria, viruses, fungi, and parasites. The European project BlueAdapt is investigating whether we can already start preparing based on current knowledge. The focus is on gaining more insight into Europe’s coastal regions.
We still know too little about the effects of climate change on pathogens, but it is important to study how this will develop in the coming years. That’s why microbiologists in BlueAdapt are working closely with, for example, modellers who aim to predict risks in time. As part of this European collaboration, field measurements are taken, laboratory tests are conducted, and models are developed and validated in consultation with the managers of the studied areas.
Due to climate change, some areas are experiencing more frequent heat, making a day at the beach and swimming a welcome way to cool down. Being near or on the water and in nature also benefits our mental and physical health. Europe’s coastal areas, therefore offer significant added value for its residents.
In the Netherlands, Deltares is responsible for two case studies in the Netherlands within BlueAdapt. One of these cases is in Katwijk, where heavy rainfall following a drought period can lead to beach pollution via combined sewer overflows. Climate change is expected to alter precipitation patterns, shifting from a more evenly distribution to one marked by more frequent sudden heavy rainfall and prolonged drought, especially during the bathing season. What does this mean for beachgoers and the coastal environment?
Hao Wang, PhD candidate specialising in water quality modelling, explains: “We are showcasing the capability of Deltares' models in the application of "Zero pollution" and "Source-to-sea" concepts. By coupling different modelling components (Emission + hydrology + hydrodynamics + water quality), we are able to track the faecal bacteria from their very initial source – household to their ultimate destination – beach. Every detail in the emission and transport of the pollution can be captured by the coupling model explicitly. We also work closely with local authorities. With the comprehensive hydrological information provided by the Rijnland Water Board and KNMI, our coupling model can predict the risk events caused by sewer overflows, which can be a powerful tool to guide the Katwijk municipality on open or close the beach."
Though the research is very case-specific, the method has a larger potential. We hope this work provides a workflow for coupling models to
tackle waterborne pollution issues in inland and coastal waters
Hao Wang, Phd candidate water quality modelling
In the Grevelingen, Franco Forlano, a PhD candidate environmental microbiology and waterborne health risks, is studying Vibrio bacteria. This type of bacteria can make people sick, with cholera being the most severe example. That disease is also caused by a Vibrio bacterium, but fortunately, that specific type is not found in Dutch waters. Franco’s research directly supports Hao Wang’s work. The Grevelingen is also a place where many people encounter the water.
Forlano explains: “First, we investigate which bacteria are present in the water. For twelve months, we collect water and sediment samples, specifically looking for Vibrio species that cause illness in humans, and the factors that influence their spread or decline.” Collecting samples requires careful preparation. Forlano and his team first plan the locations, materials, and logistics. On the day of sampling, the samples must be taken from precisely determined locations and as quickly as possible to begin the analysis. Such an analysis can take more than 14 hours. Forlano: ‘So once we can make predictions with a model, this would be very practical.’
Europe has more than 20,000 bathing water sites, and over 50% of the European population lives within 50 km of the sea. BlueAdapt aims to gather as much knowledge as possible about health risks and share it with policymakers, managers, and residents of these areas.
On 25-26 June 2025, all project partners from BlueAdapt will gather in Delft to share their knowledge and determine what still needs to be done in the final year of this European project to make the knowledge accessible and actionable.
