The quality of bathing water is essential for the protection of the health of citizens and plays an important role also in terms of the protection of the natural environment and the economic aspects in the tourism sector. For this reason, specific monitoring is carried out throughout the bathing season. With regard to the bathing season 2024, more than 31,600 samples of seawater and lake were collected and analyzed on a total of over 5,000 km of bathing coast. At municipal level the km of coast are divided into more or less extensive bathing waters, for a total of 5,506 bathing waters. The results of the analysis, in addition to guaranteeing the absence of hygienic health risks during the season, have also allowed to classify the waters. The classification was made using the results of the monitoring carried out during the 2024 bathing season and those of the previous three seasons (2023-2022-2021). At the national level, most of the waters are excellent in the classroom (91%), however, however, there are still critical issues due to the presence of water in the low class (1.1%) and not classifiable (1.1%), for which it is not possible to make a quality judgment because most are newly identified and have not completed the 4-year cycle of monitoring, necessary for classification. Even at the regional level, the percentage of water in the excellent and good classes is the highest.

Ostreopsis cf. ovate it is a potentially toxic Bentonic microalga, now present in most of the Italian coastal regions with blooms that can give rise to human intoxication phenomena and toxic effects on benting marine organisms (states of suffering or mortality). The continuous expansion along the Italian coasts of Ostreopsis cf. ovate , of its blooms and the health, environmental and economic problems associated with it, has led to establish a microalga surveillance monitoring program since 2007. This activity has been carried out annually in the summer season by the regional environment agencies (ARPA). The data provided so far by the ARPA, collected and processed by Ispra have clarified the distribution and performance of the blooms at national and regional level. To date, the microalga has been found at least once in the monitoring campaigns carried out so far in 12 coastal regions out of 15. In 2024, the Ostreopsis CF. Ovata is present in 11 coastal regions or in 147/196 stations (75%), while it is absent in all samples taken along the Coste of Emilia-Romagna, Marche, Molise and Veneto.