Blue-green algae - check the water before you swim

News Published 29 Jul 2013 Last modified 02 Oct 2017
1 min read
Photo: © Maurizio Pucci
Most beaches, lakes and rivers in Europe were clean and healthy last year. But water quality can be affected by many unforeseen factors, including sewage, agricultural waste and algae. The European Environment Agency (EEA) recommends checking local water quality information before you jump in.

The EEA’s annual Bathing Water report found the water quality in Europe was very good in 2012. Approximately 94 % of the 22 000 beaches, lakes and rivers assessed met the minimum standards last year.

But what about this year? It is expected that most sites will have similar water quality to previous years, as the environmental pressures are the same in most cases. However, this season a combination of warm weather, relatively calm conditions and in some areas a considerable level of nutrient pollution has led to blue-green algal blooms have appeared in some lakes and near some beaches. In general, the blue-green algal blooms are worse in lakes, but are also present in seas, including the Baltic Sea and North Sea.

Bloom and scum-forming blue-green algae can produce toxins. These toxins can kill wild animals, farm livestock and domestic pets. In humans, they can cause rashes after skin contact and illnesses if swallowed. Not all blue-green algae blooms and scums are toxic, but you can’t tell just by looking at them, so it is best to assume they might be and check the information provided by local authorities.

Local authorities must monitor water quality where people commonly swim, taking samples either where most bathers or the greatest risk of pollution is expected, according to the EU Bathing Water Directive. If levels of bacteria or blue-green algae are dangerous, they must inform swimmers. In cases of serious pollution they must close the bathing site.

The EEA’s Water Watch application shows water quality information for the last few years, and some authorities also upload current information during the course of the summer. Individuals can also post their rating of each bathing site.

You can also check the homepages of the local authorities to find the most recent information on algae and up-to-date information on water quality at your local bathing site.

Explore Water Watch full-screen here.


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