Efficiency of lead and cadmium excretion in populations of Orchesella cincta (Collembola) from various contaminated forest soils.
Abstract
Population differentiation in the collembolan Orchesella cincta under the influence of metal soil pollution was studied by measuring Pb and Cd excretion efficiency in individual Collembola from various sites. Total and exchangeable fractions of Pb, Cd, Zn, Cu, Fe and Ca were determined in the A-horizon of forest soils at ten locations in the Netherlands, Belgium and Germany.Concentrations of Pb and Cu were higher in the A0-horizon than in the A00-layer. Mobility of the elements decreased in the order Cd, Pb, Zn, Cu.Pb and Cd concentrations in O. cincta varied with site contamination, while Zn and Cu concentrations were more constant. The metal concentrations in Collembola were not clearly related to any particular chemical fraction of the soil metas. Resistance of O. cincta to Pb and Cd was studied by budget experiments and standardized assays of metal excretion.Intestinal assimilation from dietary exposure was 0.4% for Pb and 8.3% for Cd. From the assimilated amount, 48% of Pb and 30% of Cd was excreted per moulting interval by intestinal exfoliation. Although there was considerable interindividual variation, the average excretion efficiency was not influenced by physiological effects of such factors as degree of exposure, weight or sex.Comparison of ten populations showed that high soil contamination in mining areas resulted in populations of O. cincta having an increased average excretion efficiency for Pb and Cd.