A friend of mine did a research project about this exact thing about 35 years ago at Penn State University. He used fresh water muscles and clams. The project was very compelling to many scientists and environmental types. The group working with him made the strain gauge sensors and were able to calibrate the mollusks' behavior to various pollutants, so they could tell what exactly was in the water. It was all very interesting. I wouldn't be surprised if this Polish thing is based on his work.,(reply>), @Tvoja Starah Not so, but I understand your skepticism. It is a long time ago, could be parallel work. I can't ask, he passed away not too long ago.,(reply>), Probably the other way around