Toxic blue-green algae confirmed in Baltic Sea: avoid these waters

Swimmers beware: several public health offices are warning against bathing at certain Baltic Sea beaches because of blue-green algae. Skin contact may trigger allergies and stomach upsets. In the Baltic Sea, the ongoing heat is leading to increased growth of algae. Plenty of sunshine and high water temperatures favour their reproduction. The Hanseatic city of Rostock is now warning swimmers about certain Baltic Sea beaches. Bathing warning issued West of Warnemünde, a carpet of algae has been observed in the Baltic Sea, the Hanseatic city of Rostock said on Saturday. There is suspicion that these are blue-green algae, according to the Office for Fire Protection, Emergency Services and Disaster Control. The update on Tuesday: Rostock’s public health authority has confirmed that these are blue-green algae, which have been detected in the Baltic Sea. The responsible health authority therefore advises against bathing in these waters. Skin contact with blue-green algae can cause swelling, irritation or allergic reactions. In severe cases, it can lead to vomiting and gastrointestinal illness. The health authority is urging particular caution for children and dogs. Dogs should also not drink the water. Which beaches are affected? No formal bathing ban has been imposed, but the bathing warning applies to the Baltic coast off Warnemünde. This concerns beach sections 30 to 36. On Google Maps, the affected area is shown in the stronger colours. Blue-green algae can also develop in bathing lakes across Germany. For more than 20 years, however, bathing waters in Germany have generally been safe. If health risks do arise in isolated cases, the authorities react quickly. To this end, the state agencies regularly measure the presence of various bacteria every two or four weeks or once a month. The results are published in so-called bathing water maps and are designed to protect swimmers from potential health risks. Responsibility lies with the regional public health offices. Click on your region on the map to access the relevant bathing water map. What exactly are blue-green algae? An algae carpet is the term used when a large quantity of algae forms a dense, continuous layer made up of massively proliferating algae or cyanobacteria. Strictly speaking, blue-green algae are tiny bacteria rather than the long, green, hair-like plants. They often float freely in the water and form a slimy, bluish-green film on the surface. "In warm, sunny weather and nutrient-rich water they can reproduce rapidly and accumulate at the surface in visible carpets," the city of Rostock explained in a statement. Wind and currents can cause these accumulations to shift or disperse at short notice. The so-called "blue-green algae" attract attention because they can produce toxins that are hazardous to health, according to the cyanobacteria factsheet from the Leibniz Institute for Baltic Sea Research Warnemünde. In general, the toxins produced by blue-green algae are harmless to healthy people at low concentrations. Not all types of blue-green algae produce these toxins. However, in these temporarily formed carpets the concentration of toxins can rise to levels that pose a risk to health. In humans, this can lead to skin irritation and, after swallowing the water, to nausea and vomiting, the factsheet continues. According to the Leibniz Institute, animals that have drunk water enriched with the toxins have repeatedly died in the past, including cattle, dogs and ducks. Blue-green algae were also a frequent problem during last year’s bathing season after long hot spells. In just under half of all lakes closed to swimmers, cyanobacteria were the cause, according to the Federal Environment Agency. Bathing risk also from vibrios The particularly warm temperatures also favour other bacteria such as vibrios. Two people in Germany have died this year following a Vibrio infection. According to the Robert Koch Institute (RKI), 17 cases have been recorded so far. However, serious courses of illness mainly affect older people and those with a weakened immune system or pre-existing conditions such as diabetes, liver disease or serious heart conditions, the RKI notes. Young, healthy adults only rarely fall seriously ill. The two deaths recorded so far this year each involved very elderly people, according to the RKI.