Nickel in the Environment: Bioremediation Techniques for Soils with Low or Moderate Contamination in European Union

The review deals with the environmental problem caused by low or moderate nickel concentrations in soils. The main effects of this potentially toxic element on the soil biota and the most common crop species are addressed. Moreover, the paper emphasises biological remediation methods against nickel pollution in European soils. The focus is on the well-accepted phytoremediation strategy alone or in combination with other more or less innovative bioremediation approaches such as microbial bioremediation, vermiremediation and the use of amendments and sequestrants. Results acquired in real field and laboratory experiments to fight against nickel contamination are summarised and compared. The main objective was to evidence the ability of the above natural techniques to reduce the nickel concentration in contaminated sites at a not-risky level. In conclusion, the examined works agree that the efficiency of phytoremediation could be implemented with co-remediation approaches, but further studies with clear and comparable indices are strongly recommended to meet the challenges for future application at a large scale.