Page 160 - Soil Degradation, Conservation and Remediation

Chapter 6
Soil Pollution

Soil pollution is the accumulation of a substance, native or introduced, in soil at a
level harmful for the growth and health of organisms, including microorganisms,

plants, and animals. Hazardous substances find their way to the soil with domestic,
municipal, industrial, mining, and agricultural wastes and industrial and agrochemicals
such as fertilizers and pesticides. The most important categories of soil pollutants
are the persistent organic compounds such as PAHs, PCBs, PCNs, and PHEs and
heavy metals such as Pb, Cd, As, Hg, Zn, and Cu. These substances, above a critical
level, are toxic to plants and animals, including human. These soil pollutants can be
removed by physical methods such as soil washing, encapsulation, and vitrifi cation;
chemical methods such as immobilization, precipitation, and oxidation; and biological
methods such as microbial and phytoremediation. Hyperaccumulator plants are
often employed for the remediation of soils polluted with heavy metals.

6.1 Pollution and Soil Pollution

Pollution is defined as the introduction of any substance to the environment that
adversely affects the usefulness of a resource. The substance that is introduced and
that adversely affects the environment is the pollutant. According to Van Der Perk
( 2006 ), pollution and contamination are two terms used synonymously to mean the
introduction into the environment by humans of substances that are harmful or
poisonous to people and ecosystems. According to many other authors, however,
meanings of soil pollution and soil contamination are different. To them, soil contami-
nation is the introduction to the soil of a chemical substance which was not originally
present (de Haan and van Riemsdijk 1986 ); and soil pollution is the presence of a
chemical substance in soil in concentrations higher than natural as a result of human
activity and that has a detrimental effect on the soil environment and its components

(Kabata-Pendias and Pendias 2001 ). For simplification, we use the term soil pollution
to mean the presence of a substance, either introduced or native, above the threshold
level. Soil pollution is a global problem that threatens the life of microorganisms,

K.T. Osman, Soil Degradation, Conservation and Remediation, 149
DOI 10.1007/978-94-007-7590-9_6, © Springer Science+Business Media Dordrecht 2014