DEN HELDER, Netherlands — The next time you order mussels for dinner, think twice. You may be about to eat a first-class sentinel in the fight against pollution.
Scientists have been using mussels for years to monitor pollution, analyzing the chemicals deposited in their tissue as they filter more than 10 gallons of water daily to extract algae for food.
"A mussel is almost a printout of water quality," scientist Martin Scholten of the Dutch Applied Physics Research Bureau told Reuters in an interview.
Ironically, the bureau has become a specialist in mussels because it once fought them in the 1960s by developing special toxic paints to prevent their growth on hulls of ships and oil rigs. Now it is helping countries as far afield as the United States and India to deploy the mussel in the fight against pollution.
"Mussels give better clues than water samples because they show the effects of pollution on the environment. Mussels tell you just how healthy the water is," Scholten said.
He said mussels are excellent in helping scientists trace the presence of carcinogens in water because cancer shows up in a mussel within weeks.
"What we find in a mussel is a precursor of what other animals, and to some extent even humans, can expect to get," Scholten said.
Baskets of mussels are placed at regular intervals and at fixed points in rivers and coastal waters to monitor pollution trends.
Mussels maintain year-round vigils at the entry points of the Rhine and Meuse rivers flowing from West Germany and Belgium. They show markedly lower metal density levels in the Rhine but substantial increases in those of the Meuse.
Taking the mussel's filtering potential to the extreme, the Dutch are even experimenting to see if they can filter, and thereby purify, a stream by hanging huge fishing nets filled with mussels across it.
The advent of small, inexpensive computers has led to the development of the "mussel monitor"--an early warning system based on the mussel's reflex shutting of its shell at the first sign of danger. The device is a waterproofed, battery-powered computer with eight living mussels attached to the outside.
Sensors are attached to each of the mussel's two shell valves and linked by wire to the computer, which can be programed to set off an alarm when several mussels shut their shells simultaneously--a sure sign that something is wrong.
The invention, which is expected to cost about $12,500 when it goes on sale next year, has attracted interest from Dutch, British and U.S. environmental agencies.