Comprehensive analysis of pharmaceutical and illicit drugs contamination in thermal swimming pools: Occurrence, distribution, and potential impact.

The contamination of aquatic environments by micropollutants, including pharmaceuticals and illicit drugs, is a growing global issue with significant implications for environmental and public health. This study addresses a critical knowledge gap by examining pharmaceutical and drug contamination in thermal swimming pools, which are often legally discharged into water bodies without treatment. A total of 49 water samples from 19 distinct thermal pools were analysed, targeting 101 compounds, including pharmaceuticals, illicit drugs, and their metabolites. High-frequency contaminants were identified including caffeine, theophylline, cardiovascular medications (bisoprolol, metoprolol, telmisartan), antidepressants (venlafaxine, citalopram), antihistamines (cetirizine, diphenhydramine), the analgesic tramadol, the antiepileptic carbamazepine, and the illicit drug methamphetamine. The study revealed that these substances were present in more than 30% of the samples, with some occurring at relatively high maximum concentrations, e.g. caffeine (69 μg/L), and methamphetamine (1.8 μg/L). Notably, certain categories of targeted micropollutants, such as cardiovascular medications and illicit drugs, were found to be more prevalent in specific pools. A higher occurrence of cardiovascular drugs has been observed in a pool predominantly designed for relaxation and thus probably preferred by older people. In this pool also notably high levels of illicit drugs were found. The presence of illegal drugs was also confirmed in the children's pool. This study contributes valuable insights into the patterns of micropollutant distribution in thermal pools and emphasises the necessity for enhanced monitoring and management strategies to mitigate environmental and public health risks posed by micropollutants, as well as the possible further impact on aquatic ecosystems.