The Role of Soil Organic Matter in Trace Element Bioavailability and Toxicity

Abstract

©Springer Science+Business Media, LLC 2012. All rights reserved. Soil organic matter (SOM) is a highly important pedospheric variable for agricultural practice and ecological functions. A decline in SOM content during the last two centuries has affected agricultural areas in many countries. Among multifunctional roles of SOM, one of the most crucial is that, due to its huge reactive interfaces, SOM strongly competes with other soil matrix constitutes/ligands in trace element (TE) adsorption/chemosorption. Thus, declining SOM content may cause soil degradation, particularly from the standpoint of disturbing soil's capacity to retain potentially toxic TEs and therefore increase a risk of their migration in the environment. Using geochemical modelling with realistic natural conditions, we highlighted the importance and complexity of SOM in the rhizosphere interactions with some of the widespread and potentially toxic TEs. It was shown that biogeochemistry of Cd, Zn and Cu may vary distinctly in relatively similar environmental conditions (e.g. narrow pH range, same SOM content and temperature), thus influencing their mobility and bioavailability, i.e. toxicity in the soil plantanimal continuum.