[Hygiene of bathing waters]

Area of Science:

• Environmental microbiology
• Public health
• Water quality assessment

Background:

• Bathing water quality is assessed using European Community (EC) Directive 76/160/EC standards.
• Previous monitoring indicated low exceedance rates in South Bavarian lakes.
• River waters showed higher levels of non-compliance with bathing water standards.

Purpose of the Study:

• To evaluate the bathing water quality of South Bavarian lakes and rivers.
• To assess the effectiveness of current hygienic parameters and propose revisions.
• To identify emerging microbial threats in bathing waters.

Main Methods:

• Water quality monitoring of lakes and rivers from 1990 to 1999.
• Analysis of bacterial indicators: total coliforms, Escherichia coli, fecal streptococci.
• Detection of specific pathogens: Enterohaemorrhagic E. coli and thermophilic campylobacters.

Main Results:

• Lakes rarely exceeded EC limit values (0.3-2.1%), while rivers frequently did (17-35.3%).
• Total coliforms proved useful in detecting fecal pollution events not indicated by E. coli.
• Over 50% of lake samples exceeded future fecal streptococci limits; pathogens were detected in 2-17.4% of samples.

Conclusions:

• South Bavarian lakes are generally safe for bathing, but rivers require caution.
• Total coliforms should remain a key hygienic parameter for bathing water monitoring.
• Minimizing fecal pollution sources is essential to ensure bathing water safety, especially given the presence of pathogens.