Fate of some heavy metals in soils: a review

Abstract

This review revealed that heavy metals are naturally components of the soil orchestrated by weathering processes and that the abundance of these metals in our soil environment nowadays is due to numerous anthropogenic activities. These heavy metals are in two major categories namely the essential and non- essential ones. The essential heavy metals are needed in trace amount by living things for their physiological processes. But at higher concentration, it is hazardous in plants and animals. On the other hand, the non essential ones aredangerous to plants and animals even at low concentrations. This write-up further showed that soil pH, organic carbon, available P, oxides, effective cation exchange capacity, moisture content, oxidation-reduction state of the metals, ion exchange and sorption capacity of the metals are some of the soil factors influencing the fate and availability of the heavy metals. At lower levels of these soil factors, heavy metal ions are rendered free in the solution thereby making them available to plant and underground water. However, the most prominent soil factor influencing availability of these metals is the Soil pH. Raising some of these soil factors to appropriate levels have been discovered to reduce the availability of the heavy metals to mankind.