>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.
So, slightly different but here's a nice video from Steve Mould about hepatitis being spread around the world by freshwater mussels, which were contaminated when storm drains overflowed into a river, taking sewer effluent with them.
You can do image analysis to count the shellfish in the image, and attach an “open” or “closed” status to each. Once you have a reliable field of Boolean values, you can detect anomalies in the close count.
You could then have a grid of tanks with inlets from the clean water supply and outlets to the sewer where you monitored (more or less real time) the reaction to our clean water supply.
