Heavy Metals Bioavailability in Soils and Impact on Human Health

This chapter provides an overview of the knowledge on heavy metal entry to soils, their mobility and bioavailability to plants in relation to various factors and properties of soils and finally on transfer pathways of heavy metals to humans causing health problems. The most important factors which affect their mobility and availability are soil pH, soil texture, soil organic matter and its form, oxidation-reduction potential, ionic strength, chemical speciation and nature of contamination, and iron and manganese oxides in soils. However, sandy soils, distinguished by a low sorption capacity and acidity, weakly absorb heavy metals, which lead to relatively high mobility and bioavailability to plants than clayey soil. Soils provide all food and fodder consumed by humans and animals, but they are also a source of heavy meals , caused either by geogenic process in soils or anthropogenic activities which lead to elevated levels of these metals in plantor animal-based foods implicating the human health either positively or negatively.