Heavy metals occur naturally as constituents of the Earth’s crust (Singh et al. 2011) and are introduced to ecosystems via natural processes (Mahmood et al. 2012). Since they are nonbiodegradable, they can accumulate in the environment (Ali et al. 2013) and cause contamination. Nowadays, contamination of soils with heavy metals has become a worldwide problem and a serious threat to the environment because of increasing anthropogenic activities like mining, uses of fertilizers, wastes, sewage sludge, pesticides, wastewater irrigation, coal combustion residues, atmospheric deposition, etc. (Wuana and Okieimen 2011). In a critical review, Su et al. (2014) conclude that heavy metal contamination refers to the excessive deposition of toxic heavy metals in the soil caused by human activities. This new volume will focus on the achievements of the last years on sources of heavy metals in soils and monitoring strategies, adaption strategies of plants and bacteria in response to heavy metals, approaches for the remediation of contaminated soils, and genetic engineering as a tool to cleaning up contaminated soils. The volume is organized in 5 parts and contains 23 chapters.
