The control of water quality in the Polish capital Warsaw is entrusted to...mussels.
No joke - eight mollusks with sensors glued to their shells monitor and automatically shut off the city's water supply if the water in the pipes becomes unsafe for the population.
When the water quality drops, the mussels close their shells, triggering the sensor and alerting the control computers.
If four out of eight mussels close their shells, the control system automatically stops the water supply.
The mussels are used for 3 months before being released back into the wild.
Adult mussels and oysters can filter up to 50 gallons of water per day, but if the water becomes too toxic, they close their shells.
More than 50 water plants in Poland use the same technique...