COMPARATIVE-EVALUATION OF THE SOLUBILITY AND ALGAL TOXICITY OF COPPER-SULFATE AND CHELATED COPPER

Concentrations of total copper in solutions of several pH values and c oncentrations of total alkalinity and total hardness were always highe r when copper was applied as chelated copper than when copper was adde d in equal amounts as copper sulfate. Equilibrium calculations reveale d that the increase in copper concentrations following chelated copper treatment resulted from an increase in the concentration of complexed copper; cupric ion (Cu2+) concentration was the same with both algici des. When copper was applied to laboratory soil-water systems, copper was lost from solution slightly faster when copper sulfate was the sou rce of copper than when chelated copper was used. Results of this stud y suggest that somewhat larger and more frequent doses of copper sulfa te should be just as effective as chelated copper algicides.