Heavy Metals Dynamics in the Soil-Plant Continuum

Soil is a biologically active and physically unique and dynamic medium that has developed mainly as a result of pedogenic processes through the weathering of rocks and sediments. It consists of mineral and organic constituents, water, air and living organisms and serves among others as a medium for plant growth. Unfortunately, in the past few decades, the increase in anthropogenic activities due to rapid industrialization and modern agricultural practices has drastically increased soil pollution with heavy metals, thereby reducing soil fertility. The most commonly used indicator for soil heavy metal pollution is heavy metal bioavailability. Bioavailability of heavy metals in soils and thus their toxicity depends on numerous factors including heavy metal speciation, soil chemical and physical properties, physicochemical and biological processes that control heavy metal transformation from one form to another, as well as the soil-plant-microbe interactions. In this light, a better understanding of the patterns and driving factors of plant-soil-microbe interactions as well as the physicochemical processes that influence the behavior of heavy metals in the soils such as complexation, cation exchange, specific adsorption/desorption reactions and precipitation can help to clarify the processes that determine the fate of heavy metals in soil-plant continuum. Consequently, this knowledge would greatly contribute to the remediation of heavy metal polluted soils.