Remediation and Management of Contaminated Soil - Sustainable Practices in Geoenvironmental Engineering - page 426

H 2 O

Volatilization Phytovolatization

Phytovolatization

Phytodegradation

Phytoaccumulation

Degradation of
contaminants by
microorganisms

Translocation
to shoots and
storage

Phytoaccumulation

Rhizofiltration

Rhizofiltration

Root uptake

Phytostabilization

Secretion of acids
and other
metabolites

Rhizodegradation

Phytostabilization

Root sorption

Mechanisms for
phytoremediation of metals

Mechanisms for
phytoremediation of organics

FIGURE 11.12
Mechanisms of phytoremediation. (Adapted from Mulligan, C.N., Environmental Biotreatment, Government
Institutes, Rockville, MD, 2002.)

TABLE 11.2
Phytotechnology Mechanisms

Mechanism Description
Phytodegradation Uptake and degradation of contaminants within plant tissues by enzymatic activity for
remediation
Phytoextraction Uptake of contaminants by plants and sequestration into the plant tissue
Phytohydraulics Ability of plants to take up and transpire water to control hydrology
Phytosequestration Ability of plants to sequester certain contaminants into the rhizosphere through release
of phytochemicals, and sequester contaminants on/into the plant roots and stems
through transport proteins and cellular processes
Phytovolatilization Ability of plants to take up, translocate, and subsequently volatilize contaminants in the
transpiration stream for remediation
Rhizodegradation Ability of released phytochemicals to enhance microbial biodegradation of contaminants
in the rhizosphere for remediation
Source: Adapted from Interstate Technical Regulatory Council (ITRC), Phytotechnology Technical and Regulatory
Guidance and Decision Trees , revised, 2009.

immobilization, and phytostabilization can be appropriate in CDFs. The site could poten-
tially be restored for beneicial use as a wildlife habitat.

11.5.7 In Situ Bioremediation

Bioremediation involves the use of microorganisms to degrade organic contaminants com-
pletely or to less toxic components (USEPA, 2013a). Usually, an electron donor or energy