Chapter 15 - Magnetic Properties of Soils

Abstract

Iron-containing minerals, i.e., magnetic minerals, constitute an intimate part of a soil. These can be derived from the parent rock from which the soil developed, or can be formed in situ, or can be deposited from the atmosphere, originating from natural or anthropogenic sources. Recently, measurement of the magnetic properties of soils have found an increased use in detecting pollution, as a substitute of more time-consuming chemical techniques. The current chapter provides a brief background of the basic concepts of magnetism in order to define the parameters that are used in studies of contamination of soils. A detailed discussion is provided about the various classes of magnetic materials together with the methods that are used to measure magnetic parameters. The effects of several factors such as the presence of iron oxides, mineralogy, and grain size on the magnetic parameters are discussed, as well as, the dependence of the soil magnetic susceptibility on parent lithology, climate, oxidation/reduction, organic matter, topography, sediment source, particle size, and time. The relation between soil contamination, by heavy metals and organic pollutants, and the magnetic properties of soils are detailed based on recent scientific findings. Finally, the function of magnetic bacteria in the presence of contaminants and their impact on natural soil remediation as well as the measurement of a soil's magnetic properties is discussed.