Regulations concerning natural swimming ponds in Europe: considerations on public health issues.

Natural swimming ponds (NSPs) are a new type of recreational water facility characterized by the substitution of traditional disinfection with biodepuration. While this feature meets esthetic desires of users, specific concerns on public health issues have been raised by the scientific community and local authorities. The absence of a European directive applicable to these environments leaves each country without specific and harmonized indications. The present work describes the local/national policy situation, describing adopted parameters and monitoring activities. All documents underline the need for appropriate microbiological analysis and correct water management.

Assessment of occupational and public exposure to trichloramine in Swiss indoor swimming pools: a proposal for an occupational exposure limit.

OBJECTIVES: The presence of trichloramine in the air in different indoor swimming pools has been studied in several countries. In almost all studies, the results show a possible health impact due to trichloramine among pool attendants. The main objectives of our study were to evaluate, for the first time in Switzerland, occupational and public trichloramine exposure in a representative panel of indoor pools and to propose an occupational exposure limit for trichloramine. METHODS: Measurements were done in 30 indoor swimming pools located in three regions of Switzerland: Jura, Neuchâtel, and Fribourg. All investigations were performed during the 2007-2008 winter season in order to assure closed windows and standard ventilation conditions. Trichloramine air samplings were performed at 130 cm above the floor around the pool. Analyses of free chlorine and bounded chlorine were performed on-site, and water samples were immediately sent to the laboratory for analysis of trihalomethanes, urea, and dissolved organic carbon. A health questionnaire was distributed to all the participants. RESULTS: Our results indicate that in all the studied facilities except one, the trichloramine concentrations were below the French reference value of 0.5 mg m(-3), and only three were equal to or slightly over 0.3 mg m(-3). Overall, our results point out a very low and consistent range of trichloramine concentrations (mean concentration of trichloramine: 0.114 ± 0.043 mg m(-3)). A total of 184 questionnaires were filled out by pool workers. Of the study population, 66% were men (n = 117), 21% were smokers (9 women and 29 men), and only 7% (n = 13) were ex-smokers. The control group was composed of 71 persons (38 men and 33 women); 22% (n = 15) were smokers and 24% (n = 16) ex-smokers. CONCLUSIONS: Our results demonstrate an increasing risk of irritative symptoms up to a level of 0.2-0.3 mg m(-3) of trichloramine. The health data in our study, as well as the review of the literature, strongly suggest fixing the trichloramine occupational exposure limit at 0.3 mg m(-3). Severe technical standards (on flocculation, filters, water flow, and ventilation systems) and regulations on water quality (free and combined chlorine, urea, and amount of fresh water) contribute to reducing trichloramine formation and, consequently, occupational and public trichloramine exposure. In addition, to ensure good public hygiene (showering before swimming), correct and regular public awareness campaigns should be undertaken.

Rumen metabolites serve ticks to exploit large mammals.

Hard ticks spend most of their life isolated from passing vertebrates but require a blood meal to proceed to the next life stage (larva, nymph or adult). These opportunist ectoparasites must be capable of anticipating signals that render suitable hosts apparent. Large ungulates that tolerate a high ectoparasite burden are the favoured hosts of adult hard ticks. Ruminants, comprising the majority of ungulate species, must regularly eruct gases from the foregut to relieve excess pressure and maintain a chemical equilibrium. Through eructations from individuals, and particularly herds, ruminants inadvertently signal their presence to hard ticks. Here, we report that all adult hard tick species we tested are attracted to cud and demonstrate that these acarines possess olfactory receptor cells for the carboxylic acid, phenol and indole end-products of the rumen bioreactor. Compounds from each of these classes of volatiles attract ticks on their own, and mixtures of these volatiles based on rumen composition also attract. Appetence for rumen metabolites represents a fundamental resource-tracking adaptation by hard ticks for large roaming mammals.