ABSTRACT
This chapter provides a review of nickel (Ni) in sediments. Ni in sedimentary deposits can be categorized in accordance with its predominant source of origin, either lithogenic (natural) or anthropogenic. Extensive Ni resources are also found in manganese crusts and nodules on the ocean floor. Aqueous speciation reactions, adsorption, and precipitation control the partitioning of Ni to sediments, and hence its mobility, bioavailability, and toxicity. Lake sediments are good indicators of pollution with heavy metal, including Ni, because freshwater lakes have been at the centers of important cultural developments for thousands of years. Ni in sediments will be discussed in rivers around the world by continent including Africa, Asia, Australia, Europe, North America, and South America. Rivers located in more remote parts of Africa, for example, the Luangwa River in eastern Zambia, are unpolluted, and Ni concentrations in surface sediment are below 20 mg kg-1. The mean Ni concentration in the delta of the Yangtze River is 35.2 mg kg-1.
