Lake Hévíz is the largest natural warm water lake of Europe. The curative mud of the lake comprises volcanic and marsh components although their species composition is hardly known yet. The aim of the present study was to gain information about the distribution and species diversity of bacterial communities inhabiting the sediment of Lake Hévíz using cultivation-based and molecular cloning methods. Samples from two depths and locations were taken in 2004 and 2007. Representatives of the altogether 255 bacterial isolates were affiliated with the phyla Firmicutes, Actinobacteria, Proteobacteria and Bacteroidetes. The most abundant groups belonged to the genus Bacillus (Firmicutes). Many of Lake Hévíz isolates showed the highest sequence similarity to bacteria known to be plant associated or members of normal human microbiota as well as participating in decomposition of highly resistant organic materials. In the three clone libraries, phylotypes belonging to altogether different phyla (Firmicutes, Actinobacteria, Proteobacteria, Bacteroidetes, Cyanobacteria, Chlorobi, Chloroflexi, Deferribacteres, Nitrospirae, Spirochaetes and Verrucomicrobia) were revealed from which members of Gammaproteobacteria and Cyanobacteria proved to be the most abundant. Regardless of the sampling times and methodology used, high spatial heterogeneities of bacterial community structures were characteristic of the sediment of Lake Hévíz.
Lake Hévíz is the largest natural thermal lake of Europe, harboring special bacterial communities. The aim of the present study was to gain information about the distribution and species diversity of the sediment microbiota, with special focus on Actinobacteria, by using cultivation-based and -independent molecular methods. Samples from two depths were taken in two different locations in October 2007. 245 strains were isolated, grouped to 85 OTUs by ARDRA, and identified by 16S rDNA sequencing. Most of the strains showed highest sequence similarity with
and related genera. Strains belonging to the phylum Actinobacteria were identified as members of
Arthrobacter, Brachybacterium, Brevibacterium, Curtobacterium, Friedmanniella, Gordonia, Kocuria, Microbacterium, Micrococcus, Micromonospora, Mycobacterium, Rhodococcus, Streptomyces
. Two clone libraries were constructed from H3M and H4M samples, providing 288 and 192 clones which were grouped to 150 and 125 OTUs, respectively, by ARDRA. The two most abundant group of the H4M library were OP8-related. The phylum Proteobacteria was represented mostly by
-Proteobacteria, other relevant groups were Cyanobacteria, Bacteroidetes, Acidobacteria and
-Proteobacteria. The H3M library was dominated by Cyanobacteria, Verrucomicrobia,
-Proteobacteria. Chloroflexi, Bacteroidetes, Spirochetes and Firmicutes were scarce. Results from the clone libraries were compared to the length-heterogeneity-PCR fingerprints of the communities.
Within this work, the activity concentrations of uranium isotopes (234U, 235U, and 238U) were analyzed in some of the popular and regularly consumed Hungarian mineral-, spring-, therapeutic waters and tap waters.
Samples were selected randomly and were taken from different regions of Hungary (Balaton Upland, Bükk Mountain, Somogy Hills,
Mezőföld, and Lake Hévíz). Concentration (mBq L−1) of 234U, 235U, and 238U in the waters varied from 1.1 to 685.2, from <0.3 to 7.9, and from 0.8 to 231.6 respectively. In general, the highest uranium
concentrations were measured in spring waters, while the lowest were found in tap waters. In most cases radioactive disequilibrium
was observed between uranium isotopes (234U and 238U). The activity ratio between 234U and 238U varies from 0.57 to 4.97. The calculated doses for the analyzed samples of spring water are in the range 0.07–32.39 μSv
year−1 with an average 4.32 μSv year−1. This is well below the 100 μSv year−1 reference level of the committed effective dose recommended by WHO and the EU Council. The other naturally occurring alpha
emitting radionuclides (226Ra and 210Po) will be analyzed later to complete the dose assessment. This study provides preliminary information for consumers and
authorities about their internal radiological exposure risk due to annual intake of uranium isotopes via water consumption.
, Borbély É, Kiss T, et al. Investigation of LakeHévíz
mineral water balneotherapy and Hévíz mud treatment in murine osteoarthritis and
rheumatoid arthritis models. Evid Based Complement Alternat Med. 2018; 2018