Waters that are designated as bathing waters must meet certain requirements with regard to their microbiological water quality. These requirements are formulated and laid down in Directive 2006/7/EC of the European Parliament and of the Council of the European Communities (EC Bathing Water Directive of February 15, 2006). In order to implement this directive, the state of Lower Saxony issued the Ordinance on the Quality and Management of Bathing Waters (Bathing Water Ordinance) on April 10, 2008. This defines the binding quality criteria for Lower Saxony's bathing waters. Compliance with the limit values is monitored by regular tests. The data collected is reported to the Federal Ministry for the Environment via the Lower Saxony State Health Office. The data is collected here and submitted to the EU Commission in a comprehensive annual report.

The Public Health Department conducts sampling of bathing waters every 14 days during the swimming season. At each swimming area, water samples are collected for laboratory analysis, and on-site measurements—such as water clarity, water temperature, and pH level—are taken. In addition, an assessment of local conditions at the swimming area is conducted, including algae blooms, mineral oils, tar residues, color, surfactants, phenol odor, transparency, pH level, water temperature, and rat infestation. If any abnormalities are detected, additional water samples are collected for analysis. The samples are then analyzed microbiologically—and, if necessary, chemically—at an accredited laboratory.

The test results are forwarded to the public health department, which promptly publishes them online.

If the limit values for Escherichia coli and enterococci are exceeded, follow-up tests are conducted immediately. If this follow-up test confirms that the limits have been exceeded, a bathing ban must be imposed on the bathing area until further tests demonstrate that the situation has improved.

Key Parameters in Detail

As part of the monitoring program, Lake Salzgitter is also subjected to a visual inspection for contaminants such as tar residues, floating objects (e.g., wood, plastic, bottles, glass, rubber), and other substances.

Escherichia coli (“E. coli”) and intestinal enterococci are bacteria found in the normal intestinal flora of warm-blooded animals (e.g., humans, waterfowl, and grazing livestock). In the monitoring of bathing waters, they serve as indicators of massive fecal contamination, e.g., from manure, sewage sludge, wastewater discharges, or very high numbers of waterfowl per square kilometer. With such a large volume of contamination, dangerous pathogens can also enter the water and pose a source of infection for humans. If none or only a few such bacteria are found, one can be fairly certain that no other pathogens of serious diseases—which are excreted from the intestines—are present in the bathing water.

By the way: The corresponding “input” into the lake from people swimming or dogs and cats playing is not a health concern.

The new EU Bathing Water Directive 2006/7/EC stipulates that bathing waters must be tested for blue-green algae (cyanobacteria) when necessary. When they occur in large quantities, they can produce both allergenic and acutely toxic substances in effective concentrations. As soon as algae growth begins, appropriate samples are taken.

Do not feed waterfowl, as this increases the parasite infestation and thus the possibility of bathing dermatitis (cercaria dermatitis)!

Bath dermatitis is caused by cercariae swimming in the water. Cercariae are the larvae of sucking worms that parasitize in the intestines of waterfowl. The eggs enter the water with the birds' excrement. They hatch into ciliated larvae, which seek out an intermediate host, i.e. various freshwater snails.
So: the more food, the more droppings the birds produce.

However, cercariae also mistakenly target humans as a false host. The cercariae penetrate the human skin, where they die and cause skin infections.

Cercaria infestations in Germany are generally harmless to humans, but are unpleasant and annoying due to the skin eczema with severe itching.

Treatment is exclusively symptomatic with antipruritic and anti-inflammatory ointments, creams and lotions.

The occurrence of cercariae is not related to the hygienic water quality as a bathing lake.

The public health department does not carry out tests for cercariae, which are not required by the EU Water Directive. As cercariae diseases are not notifiable, we are generally not aware of any numbers. It is not possible to predict or "measure" an accumulation of cercariae in water bodies. As cercariae cannot be seen with the naked eye due to their small size, an increased occurrence of cercariae is only noticed when there are already cases of bathing dermatitis. During the swarming period of the cercariae, which lasts around a week, areas of the shore rich in plants should be avoided, as this is where the water snails and therefore most of the cercariae are found.

Recommended rules of conduct for bathers cannot completely protect against cercaria infestation, but they can reduce it:

• Avoid spending long periods of time in shallow water (children in particular are at risk)
• Preferably swim in deeper or gently flowing areas
• Change swimsuits after swimming
• Rub the body well with a towel (cercariae dry out quickly)
• As a preventative measure, rub the body with the following products: SPF 15 or SPF 30 sunscreen lotion, which also offers protection against jellyfish