Abstract
In this chapter, the chemistry of copper (Cu) and zinc (Zn) and their physicochemical characteristics were studied and related to the toxicity of the metals in soils. The metals are essential nutrients in soils, but their bioaccumulation introduces toxic effects. Such effects include reduced respiration, low microbial, and microorganism activity and biodiversity and an imbalance of available essential nutrients leading to altered physicochemical characteristics, as well as low quality and fertility in the soils. The toxicity is controlled by factors such as pH and organic matter content that regulate sorption and desorption processes in soils. The toxicity in sub-Saharan Africa soils (SSA) is as a result of the mining and smelting of Cu and Zn ores where metals are introduced in soils as slug, waste rock, overburden materials, tailings, and acid mine drainage from the involved processes. The use of phosphatic fertilizers and fungicides also leads to accumulation of the metals in soils.