| Abstract: | The sediments in Blackstrap Lake, a prairie lake, contain over 90% of the non-clay fractions and its pH is near neutrality. Calcium and Mg carbonates, sesquioxidic components and their complexes with silica are present in a series of particle size fractions. The major clay minerals of the sediments are mica, montmorillonite, chlorite, vermiculite, kaolinite, and quartz. Organic matter of the lake sediments is relatively less important in the adsorption of arsenite. Calcium and Mg carbonates, micas, vermiculite, montmorillonite, kaolinite and chlorite are the active components but not the dominant components of the lake sediments in adsorbing arsenite. The porous sesquioxides and silico-sesquioxidic complexes present in a series of particle size fractions (clay, silt and sand). are the primary components in adsorbing arsenite. The retention of arsenite by these active components present in sediments would suppress the level of arsenite in fresh water and may thus restrain its movement to the food chain. |
