About & methodology
An independent initiative
This platform is developed on a voluntary basis, with no conflict of interest. It is designed and funded by an anonymous citizen, independent of any public or private organisation.
Its purpose: to make visible symptoms that many people experience without always connecting them to water quality, or knowing that they are shared by others.
The aim is to provide an honest, real-time overview so that everyone can make informed decisions based on their own health constraints.
The goal
This citizen platform aims to track Basque coast pollution with health impacts, and to cross-reference this environmental data with testimonials from beachgoers. The first indicator tracked is the micro-algae Ostreopsis; others may be added later.
Testimonials are collected anonymously, whether or not symptoms occurred. Collecting visits without any effects is also essential: it makes for a representative picture of water quality, rather than just a collection of problem cases.
The data
Concentrations come from water samples taken by the Communauté d'Agglomération Pays Basque and analysed in a laboratory, expressed as the number of Ostreopsis cells per litre. Each reading also shows the split between O. cf. siamensis and O. cf. ovata, the water temperature and whether the beach was closed by municipal order.
- "< 40" means "below the detection threshold" (treated as absence).
- Rows without a value correspond to analyses still in progress.
- Updates: manual import after each sampling campaign.
- Additional samples taken by Surfrider (Côte des Basques, Uhabia, Lafitenia) are shown for reference only, with no official value and no effect on the map or closures.
Colour bands
These bands are indicative and serve only to make the map easier to read. They do not constitute official health thresholds.
- Undetectable — No presence detected.
- Low — Present, low risk.
- Moderate — Caution advised, especially for sensitive individuals.
- High — Risk: avoid swimming and the seashore.
- Closure — Beach closed by municipal order.
Known limitations
- Colour thresholds are indicative, not official.
- Correlation between concentrations and testimonials does not imply causation.