Formed at the interface between the atmosphere and the earth’s crust, soil is a complicated and variable medium made up of a complex of mineral and organic solids, aqueous and gaseous voids and a considerable microbial biomass. Soil is inherently heterogeneous because of the wide range of rock types and other environmental factors that influence soil formation (climate, cover, time, etc.). All soils contain humus, the polymerized organic matter formed by the decomposition of dead vegetation. This normally makes up between 0.1 per cent and 1 per cent of the soil but can be as much as 70 per cent in peaty soils. Soils also contain variable quantities of primary minerals from the parent material or from ice or waterborne deposits, together with secondary minerals such as hydrated metallic oxides. The latter with humus forms the colloidal fraction that can give soil a sorptive property, which is important in understanding pollutant fate and behaviour.
|Title of host publication||Environmental Medicine|
|Number of pages||9|
|Publication status||Published - 1 Jan 2010|
Bibliographical notePublisher Copyright:
© 2010 Edward Arnold (Publishers) Ltd.