[Development and monitoring of the hygienic water quality at bathing facilities in northwest Germany from 1989 to 1991].

Since the introduction and strict application of EC guidelines on the monitoring of bathing waters began in Lower Saxony in 1989, it has been possible for the first time to reach a comprehensive evaluation of the water quality on the North Sea coast and in the rivers and lakes of this state. The 7648 samples which were analysed in this period produced the most favourable results on the East Friesian Islands, followed by the vast majority of the mainland bathing resorts and some lakes. On the lower stretches of the River Weser and in a few lakes levels were registered at times which exceeded the limits to such an extent that bathing was impossible. In 1991 extreme germination of total coliform bacteria was observed for the first time, presumably due to eutrophic conditions in combination with high water temperatures.