Abstract
Natural thermal bathing pools contain geothermal water that is very popular to bathe in but the water is not sterilized, irradiated or treated in any way. Increasing tourism in Iceland will lead to increasing numbers of bath guests, which can in turn affect the microbial flora in the pools and therefore user safety. Today, there is no legislation that applies to natural geothermal pools in Iceland, as the water is not used for consumption and the pools are not defined as public swimming pools. In this study, we conducted a microbiological analysis on three popular but different natural pools in Iceland, located at Lýsuhóll, Hveravellir and Landmannalaugar. Total bacterial counts were performed by flow cytometry, and with plate count at 22 °C, 37 °C and 50 °C. The presence of viable coliforms, Enterococcus spp. and pseudomonads were investigated by growth experiments on selective media. All samples were screened for noroviruses by real time PCR. The results indicate higher fecal contamination in the geothermal pools where the geothermal water flow was low and bathing guest count was high during the day. The number of cultivated Pseudomonas spp. was high (13,000–40,000 cfu/100 mL) in the natural pools, and several strains were isolated and classified as opportunistic pathogens. Norovirus was not detected in the three pools. DNA was extracted from one-liter samples in each pool and analyzed by partial 16S rRNA gene sequencing. Microbial diversity analysis revealed different microbial communities between the pools and they were primarily composed of alpha-, beta- and gammaproteobacteria.
Highlights
Geothermal heat is found in over 700 locations in Iceland [1]
The objective of the study was to assess the microbiological status of Icelandic natural thermal bathing pools by evaluating their microbial diversity by partial 16S rRNA gene sequencing; by comparing total cell count performed by flow cytometry to total viable plate count analysis
Total bacterial count refers to the number of cfu in 1 mL of sample
Summary
Geothermal heat is found in over 700 locations in Iceland [1]. Natural thermal bathing pools are important local resources that have been used by the people in Iceland for centuries. A natural thermal pool is defined as a pool with geothermal water that has not been sterilized, irradiated or treated in any way [2]. There is no legislation that applies to the natural pools in Iceland, so people bathe in them entirely at their own risk. Water for traditional or municipal swimming pools must always fulfill bacteriological water quality criteria and contain a certain chlorine concentration to keep it free from bacteria. When the quality of natural thermal pool water is assessed, it does not comply with the criteria for traditional swimming pools.
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callMore From: International Journal of Environmental Research and Public Health
Disclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
