ABSTRACT
Metals are naturally present in soils. Many metals in the soil environment may be considered to be contaminants or xenobiotics. The chapter provides some examples that highlight their diversity, roles, and implications for metal resistance. It highlights eight metals: arsenic, cadmium, chromium, copper, lead, mercury, nickel, and zinc. Since soil microbial communities and linked properties play essential roles in soil functioning, it is of importance to determine the effects of metals on them. Metals in soils are not always able to enter living organisms, and biological effects may be limited or completely absent. It is therefore important to determine metal bioavailability to understand any soil environment. The duration of exposure to a metal is a key parameter to assess metal impact. A recent and acute metal contamination caused by human activities or natural processes may have large effects on the soil community.
