Assessing the Influence of Biota on Metal Mobility in a Multi-Species Soil System (MS·3)

Multi-species soil systems (MS·3) are homogeneous soil columns that allow a combined assessment of chemical fate and effects on representative soil organisms. Theoretically, the presence of organisms can modify the movement of chemicals in the soil core. This influence was studied for copper and cadmium comparing the results on MS·3 with earthworms and two plant species versus soil columns without organisms. Metals were applied on the top of the soil at three doses: low (3.4 g Cu/ha + 1.7 g Cd/ha), medium (8.5 g Cu/ha + 4.3 g Cd/ha) and high (17 g Cu/ha + 8.5 g Cd/ha). Three organic compounds (pentachlorophenol, 4-chlorophenol and chlorpyrifos) were applied. Toxicity and metal levels in biota followed dose-response relationships. Results showed higher metal concentrations in the depth layers of MS·3 than in the soil columns. The effect was higher for the lower dose, where organisms were less affected, than at the higher doses, where very severe toxicity was observed, confirming the role of organisms in th...