Blue-green algae, E. coli, enterococci – bathing bans in 118 German lakes and rivers

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If you zoom into the map of Germany, many tiny blue dots light up, only a few red ones show up very sporadically. This is good news, because blue means water quality meets EU standards, red means poor.

The total of around 2292 dots are the official bathing spots on lakes, rivers and coasts in Germany. According to the latest EU report on the quality of European bathing water, the water quality was

90.2 percent as “excellent”, 5.9 percent as “good”, 1.6 percent as “sufficient” and 0.6 percent as “poor” (1.7 percent no rating due to missing data)

classified. This means that the vast majority, at least 98 percent, meets the EU minimum requirements.

Two intestinal bacteria are crucial for the assessment

The water quality is measured based on the concentration of two intestinal bacteria:

Escherichia coli (E.coli) and
Intestinal Enterococci

These are so-called indicator bacteria: they indicate faecal contamination of the water body. There are certain EU-wide limits that you must not exceed. They are assigned to a respective quality level on the basis of measurement data from the last four years.

Why is that dangerous? Usually these bacteria are harmless. They are found in the intestines of humans and animals. However, if the water is heavily polluted, swallowing it can lead to diarrhoea, nausea and vomiting.

Precautionary bathing ban at 118 bodies of water in Germany

But not only intestinal bacteria pose health risks. Recently there have been repeated reports of lakes with ⁠ Cyanobacteria⁠ (“blue-green algae”) are charged. Their growth is favored by high temperatures, lots of sun and little wind.

Why is that dangerous? Blue-green algae can form algae toxins and allergens that lead to skin irritation and conjunctivitis. There is also a risk of liver damage if large amounts of water are swallowed.

In Germany, bathing bans are therefore also imposed due to blue-green algae contamination. As the Federal Environment Agency reports, there is currently a precautionary ban on bathing in a total of 118 bodies of water. In more than 80 cases, this is due to the said blue-green algae, followed by 30 cases due to hygiene problems, including intestinal bacteria.

You can see exactly which bathing areas are affected and the current measurement data on the websites of the federal states or the individual districts. To do this, click on the map of Germany from the Federal Environment Agency.

Important: The EU report only refers to official bathing spots.

Germany’s most toxic lake is not included

Germany’s most toxic lake is therefore not mentioned in the EU report. The Silbersee in Nuremberg may look idyllic, but appearances are deceptive. There is a danger to life for swimmers. Swimming has been banned here since the 1960s.

It was created in the late 1930s as part of an excavation pit on the edge of the Nazi Party Rally Grounds. After the war, toxic hazardous waste was stored on its banks for decades. According to the ” Süddeutsche Zeitung “, hydrogen sulphide lies dormant at a depth of three to four meters. If the substance is whirled up by a swimmer, it gass to the surface. In this concentrated form, he can very quickly stun people and drown them. After the end of the war, up to 50 people drowned in the lake.

Again more deaths from drowning in Germany

July 25th was World Drowning Day. The World Health Organization (WHO) reports that at least 236,000 people drown each year. According to the agency, these are preventable deaths.

An increase was also recently observed in Germany. According to the German Life Saving Society (DLRG), 355 people drowned last year. That is 56 deaths more than in 2021. “This is the first time we have recorded an increase in four years,” said DLRG President Ute Vogt. Compared to the average of the past ten years, however, there are 16 percent fewer victims.

Vogt is also particularly worried about the group of children and young people. A forsa survey commissioned by the DLRG recently showed that the number of primary school children who cannot swim has doubled from ten to 20 percent since 2017. The DLRG President therefore demanded again: “Just as boys and girls learn to read, write and do arithmetic, they must also learn to swim. We need to get every child to be able to swim safely by the end of elementary school.”