Vorkommen und Verbreitung von Giardia und Cryptosporidium im Roh-und Trinkwasser von Oberflachenwasserwerken

Water samples from six different surface water treatment plants in Germany were examined for Giardia and Cryptosporidium. The results confirmed the occurrence of Giardia and Cryptosporidium in surface-and raw water supplies, in backwash waters and in drinking water. The number of the detected Giardia cysts in surface or raw water ranged from 0.1 to 320/100 1 (average 46.4/100 1), and the number of Cryptosporidium oocysts ranged from 0.2 to 832/100 1 (average 101.9/1001 1). Overall, Giardia and Cryptosporidium or both were detected in 75.3% of the raw water samples. 21.2% of drinking water samples (7/33) were positive for Giardia (range 0.2-16.8/100 1) and 36.4% (12/33) were positive for Cryptosporidium (range 0.13.-20.8/100 1). Overall, Giardia, Cryptosporidium, or both were detected in 48.5% of the drinking water samples. 84% (42/50) of the backwash water samples were Giardia positive and 82% (41/50) were Cryptosporidium positive. The mean value for Giardia was 32.9 cysts/100 1 and the mean value for Cryptosporidium was 22 oocysts/100 1. Overall, Giardia, Cryptosporidium or both were detected in 92% of the backwash water samples. (English summary)