Characteristics of Natural and Urban Soils - Dealing with Contaminated Sites: From Theory Towards Practical Application - page 115

Fig. 2.7 Adsorption of heavy metals on iron oxides as a function of pH, 20 mmol/g added. ( a )
Hematite, ( b ) Goethite (McKenzie 1980 )
Fig. 2.8 Adsorption of heavy metals on birnessite as a function of pH, ( a ) 2 mmol g − 1 added, ( b )
1 mmol g − 1 added (McKenzie 1980 )
2.4 Contamination Potential
2.4.1 Soils of Deposited Material and Former Industrial Sites
In the presence of technogenic material, an enhanced contamination potential has
to be taken into account (Nathanail and Bardos 2004 ). The level of contamination
depends upon the kind of material, the amount of material deposited, and the degree
of weathering. Table 2.5 presents the concentrations of some heavy metals being
concentrated in different sorts of ashes. While the level in coal is low, ashes reveal
higher values, in particular ashes derived from garbage incinerators. Moreover, the
table also illustrates the differences in metal concentrations between the different
kinds of ashes. It shows that metal concentrations in the silty fly ashes exceed clearly