Accumulation of Essential and Nonessential Metals by Chironomid Larvae in Relation to Physical and Chemical Properties of the Elements

Molar concentration factors for nine metals, calculated as quotients of concentrations in chironomids divided by concentrations in sediment, were systematically related to fundamental atomic properties using multiple regressions and canonical analyses. Ionization and oxidation potentials, as well as the ionization potential differential and atomic radius, were useful predictors of metal concentration factors. Their relative importance varied with lake pH. Concentration factors were higher for the essential elements Zn, Ca, and Cu than for Ni and the nonessential elements Pb, Cd, and Al. The low concentration factors for Mn and Fe were driven by high sediment concentrations and the tendency for these elements to form insoluble hydroxides.