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The calcium carbonate in freshwater clam shells is simlilar in purity to that designated reagent grade. A simple reprecipitation of the shell extract results in a product having less Sr and Mg than reagent grade CaCO(3). Clams are harvested commercially, and discarded shells are a high-quality raw material for the production of CaCO(3).

Fresh-water clams concentrate strontium-90 in their shells and may be used as indicators of the Sr(90) contamination of their environment. Analysis of data derived from the specific activity of Sr(90) in shells showed that Sr(90) released to the Tennessee River system remained in solution and that concentrations to a distance of 500 miles from the release site can be predicted on the basis of the dilution of contaminated White Oak Creek water by uncontaminated Clinch-Tennessee River water.

Filtered plankton samples subjected to sonic oscillations yielded 11 to 30 percent more chlorophyll a with cvacetone extraction than similar, nonsonificated samples. The improved chlorophyll extraction was attributed to algal cell-wall rupture.