Manganese-54 Concentration in Fall-out, Water, and Unio Mussels of Lake Maggiore, 1960–63

Abstract

THE ability of Unio (Mollusca, Lamellibranehia) to concentrate manganese has been known for more than fifty years¹. High concentrations of this element in Unionidae were also reported more recently by Vinogradov² and by Merlini³. In September 1960, manganese-54 was found in Unio mancus var. elongatulus (Pfeiffer) collected in Lake Maggiore and in nearby Lake Varese. It could not be detected in fall-out, lake water, sediment, rooted aquatic plants, gastropods or fish. After having ascertained that the ⁵⁴Mn present in Unio was not due to local contamination we supposed that this radionuclide must have been present also in the fall-out over northern Italy, but only in very low, undetectable concentrations⁴.