The use of seawater in public swimming pools could offer a more sustainable solution given the challenges posed by climate change and the growing scarcity of potable water across Europe. However, the swimming pool sector currently lacks a unified European legislative framework and faces significant fragmentation, particularly regarding the use of seawater. This scoping review applies a methodology to collect and analyze the international and national regulations of 23 coastal European countries relevant to swimming pool water safety. It provides an overview of existing European legislation on the use of seawater in public swimming pools and outlines the permitted disinfection methods. The review also highlights the highly variable and fragmented regulatory frameworks for microbiological and chemical water quality parameters, as well as the limits imposed on disinfection by-products (DBPs). Furthermore, it addresses the potential risks associated with seawater use in pools, with particular attention to the toxicity of DBPs that may form under such conditions. The findings underscore the urgent need for legislative updates in the pool sector and highlight the potential for developing specific European regulations. These would help harmonize practices across the sector and improve the management of both sustainability and public health in recreational aquatic environments.

The use of seawater in public swimming pools could offer a more sustainable solution considering the challenges posed by climate change faced across Europe and the scarcity of potable water. However, the sector of swimming pools currently lacks a unified European legislative framework and faces significant fragmentation, particularly regarding seawater use. This paper examines the existing regulatory landscape concerning seawater utilization in public swimming pools across 23 European coastal countries, providing an overview of the situation and outlining permitted disinfection methods. It also addresses the chaotic state of standardized physicochemical and microbiological parameters, as well as quality limits imposed on disinfection by-products in pool water and their toxicity. The findings underscore the urgent need for legislative updates and highlight the potential for developing relevant European regulations to standardize practices within the sector, to better manage sustainability and public health in aquatic environments.

Thermal water-supplied swimming pools are increasingly used worldwide for recreation, wellness, and therapeutic purposes, yet their management poses specific challenges due to the complex physicochemical properties of thermal and mineral waters and the need to balance microbiological safety with preservation of their natural characteristics. This scoping review adopts an integrative and comparative methodological approach, combining a systematic mapping of the scientific literature with a structured analysis of regulatory documents across 39 countries. It maps and comparatively synthesizes current evidence on health benefits, safety issues, and regulatory frameworks governing thermal pools. The analysis focuses on microbiological hazards and chemical risks related to disinfection practices, including the formation of disinfection by-products (DBPs). The review also examines emerging contaminants (CECs), including pharmaceuticals and personal care products (PPCPs), and discusses the potential role of thermal water environments in the development and spread of antimicrobial resistance (AMR). Moving beyond a purely descriptive approach, the analysis introduces a comparative framework that identifies distinct regulatory models and evaluates their implications for risk management and disinfection strategies. Thermal pools are conceptualized as integrated exposure systems generating complex mixtures with uncertain toxicological effects. The analysis reveals global regulatory heterogeneity and critical gaps in managing DBPs, CECs, and AMR-related risks, highlighting the need for integrated, risk-based and harmonized approaches within a One Health framework.

Thermal water–supplied swimming pools are increasingly used worldwide for recreation, wellness, and therapeutic purposes. However, their management presents unique challenges due to the complex physicochemical properties of thermal and mineral waters and the need to ensure microbiological safety while preserving their natural characteristics. This scoping review examines the main health benefits and safety issues associated with thermal pools and provides a comparative analysis of regulatory frameworks governing these facilities in 39 countries worldwide. Particular attention is dedicated to microbiological hazards, chemical risks related to disinfection practices, and the potential formation of disinfection byproducts (DBPs) in treated thermal waters. The review also discusses emerging contaminants (CECs), including pharmaceuticals and personal care products (PPCPs), and the potential role of thermal water environments in the spread of antibiotic and antimicrobial resistance. The analysis highlights significant global heterogeneity in regulatory approaches, especially regarding disinfection strategies and water quality monitoring. Interactions between natural water composition, anthropogenic contaminants, and disinfection processes may create chemically complex mixtures whose toxicological implications remain insufficiently studied. Adopting a One Health perspective, this review emphasizes the need for integrated management strategies and more harmonized regulatory frameworks to ensure the safe and sustainable use of thermal water pools.

This study evaluates a miniaturized Near-infrared spectroscopy MicroNIR/Chemometrics platform as a rapid tool for monitoring chloroform, a representative disinfection by-product from the trihalomethanes class. Two MicroNIR devices were tested in three configurations: reflectance measurements in glass vials and transmittance measurements in static and flow modes. Experiments were conducted with spiked distilled water over the 1–200 µg/L range relevant to regulations. Principal Component Analysis provided clear separation between blanks and chloroform-containing samples in all configurations. Partial Least Squares Discriminant Analysis achieved 100% specificity and non-error rate, with a root mean square error in prediction (RMSEP) of approximately 0.06–0.08 for static and flow measurements and 0.09–0.10 for vial mode. In the 1–20 µg/L range, Partial Least Squares Regression demonstrated comparable performance for static and flow measurements (R² = 0.91; RMSEP = 2.3 µg/L), while flow provided the lowest estimated limits of detection and quantification (2.6 µg/L and 7.9 µg/L, respectively). In the 20–200 µg/L range, flow showed the highest quantitative performance. The results support the feasibility of MicroNIR/Chemometrics as a rapid screening tool for chloroform in water, complementary to reference methods. Future work will focus on improving inter-campaign transferability, extending the approach to all regulated trihalomethanes, and validating it in real matrices.