[Caitlin]

From the LJWORLD:

By Dennis Anderson
November 5, 2007

link to Photo by Thad Allender. Enlarge photo.
Bryan Simmons emerges from the Verdigris River with a freshwater mussel in hand while surveying mussels lining the bottom of the shallow southeastern Kansas river. A century of harvesting, pollution and changes to the mussels’ habitat have caused more than 70 percent of the nearly 300 species found in the United States to be listed as threatened or endangered. Some mussels can filter out as much at eight gallons of water per day, creating a natural water filter that scientists say could help improve water quality in Kansas.

Here is an excer[pt from the full article:

History
Freshwater mussels have two shells connected by a hinge-like ligament. Adults range in size from a small stone to as big as a pie plate. Mussels can live to be 100 years old; the ridges on their shells reveal their years, like a tree. By their siphoning actions, mussels filter bacteria, algae and other small particles.
While mussels’ shells are rugged-looking on the outside, their insides are beautiful pearly purples, pinks and whites.
As settlers moved west and towns sprung up along major Midwestern rivers, mussel shells became important in the garment and jewelry industry, said Bryan Simmons, terrestrial/aquatic ecologist for the state Department of Wildlife and Parks.
Shells were harvested and shipped to factories, where they were turned into buttons and jewelry. This became a major industry along eastern Kansas rivers such as the Verdigris. Waste button shells also were used in building foundations and bases for sidewalks and roads.
Some 85 million mussels were removed from Kansas’ Neosho River in 1912, which represented about 17 percent of the nation’s total pearly products, Simmons said.
“Plastics in the 1940s helped to save the mussels,” added Edwin Miller, wildlife biologist for Wildlife & Parks. “Plastic buttons were cheaper and easier to make than buttons made from a mussel’s shell.”