Poznan. The clams filter the water. They check whether the water is polluted or clean

They are more accurate than complicated devices in the laboratory, they know “something is wrong” faster and cannot be fooled. In Poznań, mussels have been keeping water purity for 26 years. The TVN24 reporter checked what exactly their “work” is all about and whether the inconspicuous barks have raised the alarm.

In Poznań, 26 years ago, mussels were “employed” to check the safety of water, and more specifically large ones. The capital of Greater Poland was the first Polish city to decide on such a solution.

– Working as a microbiologist, I always thought to introduce a system that would work independently and would be based on living organisms. The idea was for such a system to give us information about the quality of the water. When looking at chemical tests, you can check a lot of things, but for each type of test you need a separate device – says Grzegorz Podolski, senior technologist for water quality at Aquanet.

Mussels have been “evaluating” the condition of water for 26 yearsTVN24

- Advertisement - It is different with biomonitoring. – Here one organism, in this case a clam, checks many parameters and if there is any chemical contamination, it lets you know. And that’s enough to take a sample, take it to the laboratory and see what it is about: confirm or deny that something is happening to the water. It is a system that ensures safety against pollution and even terrorist activities. The work of the mussels is closely related to what the laboratory does, adds Podolski.

Clams nourish themselves by filtering the water. They are extremely sensitive to all kinds of pollution and much more than humans. That is why they belong to the indicators, i.e. species of plants and animals that have a low degree of tolerance to changes in conditions in the environment in which they live.

How many mussels were given a “job” and how long they can work was checked and described in the instruction by scientists from the Adam Mickiewicz University in Poznań. – We have three measuring devices in the company and eight clams in each. In total, we “employ” 200 individuals during the year – says Podolski.

Within an hour, one individual can filter 1.5 liters of water. – It is a good cooperation. We have full democracy and gender equality here, because we have both male and female individuals – says Dorota Wiśniewska, spokesman for Aquanet SA in Poznań.

Each clam is first prepared and fed. Then it goes to a special flow-through aquarium. And there, for two months, they are on “duty”. – This is the time when he can work and live safely. Then the “workers” return to their natural environment, that is, to water reservoirs – explains Wiśniewska.

Biomonitoring based on mussels consists in constant, round-the-clock observation and registration of their shell movements. How it’s working?

– Mussels open the shells and every now and then take in a small amount of water, filtering out everything that is suitable for eating. When the water is polluted, they do their best to separate from it, and everyone’s shells just close at the same time. This happens within two minutes. If two or three clams close, it doesn’t have to mean anything, but if there are eight, it’s an alarm. Then our role is to find out what has upset them so much and find out if it is a real or a false alarm – says Podolski.

How wide do the shells of clams open?Paula Przetakowska / TVN24

– Have they all shut down? – the TVN24 reporter asks.

– There has not been such a situation for these 26 years. The water that goes to the mussels is of very good quality – adds Podolski.

Scientists have translated these clam responses into ‘computer language’. – The mussels are glued to the plastic pedestal. In addition, a magnet disc is glued to the shell, and a probe is mounted nearby that detects changes in the magnetic field. When the clam closes or opens, it touches the probe with this magnet. And we translate it into an image of the degree of opening and closing – explains the Aquanet employee.

Mussels have been “keeping” the purity of water since 1994 TVN24

– During these 26 years, when we talk about the work of mussels during “open doors” or educational lessons, they always arouse positive emotions and great interest. Visitors are always surprised that such small creatures play such an important role – adds Wiśniewska.

Water biomonitoring in Poland is carried out in several water supply companies, including in Łódź, Warsaw and Silesia.