Swiss bathers who plan a dip in the country's lakes and rivers during the warm weather will find varying water quality, and they're being advised not to swim in some rivers.
The water quality of Swiss lakes overall is good, and bathers can plunge in without concern. The lakes generally are cleaner than the rivers, said Hans Schudel, section chief for drinking and bathing water of the Aargau cantonal laboratory.
The Aare river, Lake Lucerne, Lake Zurich and Lake Constance, among others, were all rated good or very good in quality, according to a check of cantonal laboratories by The Associated Press.
The thousands of bathers who daily frequent these locales can expect no health problems, the probe showed.
Some rivers dirty
However, some rivers are just too dirty for swimming, according to laboratory specialists.
Swimming in rivers is generally inadvisable, said Anton Tuor, cantonal chemist in Lucerne. He warned against bathing in Geneva's rivers, not only for hygienic reasons, but also because of the biotrope, or ecology of the rivers.
In Canton Vaud, where two analyses are made each season, bathing conditions in general are good, said Eric Raetz, cantonal water inspector.
Beaches along the lakes of Morat and Joux were rated Class A - good quality. Along the Lake Neuchâtel and Lake Geneva, a majority of beaches also merited the Class A designation, while some were rated Class B, of medium quality.
By contrast, parts of the Thur river are very dirty, according to measurements made by the cantonal laboratory of St Gallen. The bacterial quality of bathing waters in the Birs river in Basel was also poor.
Bathing spots on the Rhine river in part rated only "acceptable" quality. Water tests of Lake Geneva in the Bourget Park in Lausanne were also rated "acceptable."
In some of the water tests, fecal bacteria or Salmonella were found, chemists reported.
With acceptable water quality, experts recommend against scuba diving, and advise swimmers to take a thorough shower after their swim. Swimming in strongly contaminated water isn't recommended.
Chemists rated most Swiss lakes in the "A" category. In Ticino, for example, 86 "official" beaches were rated Class A, according to the cantonal laboratory.
swissinfo with agencies