Environmental Engineering Reference
In-Depth Information
technologies, it is not invasive and, in principle,
delivers intact, biologically active soil. There is a
need to enhance research efforts on this emerging
technology. Phytoremediation research should
focus on identifying indigenous hyperaccumula-
tors that are adapted to the local climate and soil
conditions. Since phytoremediation is a slow pro-
cess, biotechnological as well as conventional
hybridization techniques should be used to
develop more effi cient metal hyperaccumulator
plant species having increasing pollutant toler-
ance, root and shoot biomass, root architecture
and morphology, pollutant uptake properties, and
degradation capabilities for contaminants.
Additional strategies should include proper man-
agement of the soil, e.g., via fertilization or chel-
ant addition to increase pollutant bioavailability,
and of the phytoremediation crops, e.g., via opti-
mization of coppicing, harvest cycles, and devel-
opment of mixed cropping systems.
7
Advantages
and Disadvantages
of Phytoremediation
Phytoremediation is well processing methods
were used at large contaminated sites, where
other methods of remediation are not cost-
effective or practicable; at sites with a low con-
centration of contaminants where only polish
treatment is required over long periods of time
and in combination with other technologies
where vegetation is used as a fi nal cap and clo-
sure of the site. There are some limitations to the
technology which include long duration of time
for remediation, potential contamination of the
vegetation, and food chain diffi culty in establish-
ing and maintaining vegetation at some sites with
high toxic levels.
8
Integrated Approaches
References
The complexity and heterogeneity of sites often
polluted with multiple metals, metalloids, and
organic compounds require the design of inte-
grated phytoremediation systems that combine
different processes and approaches. Co-cropping
of different species may enhance the overall
capabilities of a phytoremediation system to
explore the contaminated soil volume, address
different pollutants, and support differential
microbial consortia in their rhizospheres. Shared
rhizospheres may be designed to optimize the
nutritional status, e.g., by combining plants that
support N
2
-fi xation and P-solubilizing microor-
ganisms. Co-cropping could be also used to mod-
ify the bioavailability of pollutants with the plants
(Roy et al.
2007
).
Alloway BJ (1995) Heavy metals in soils, 2nd edn.
Blackie Academic and Professional, Glasgow, U.K.
Bani A, Echevarria G, Sulçe S, Morel JL, Mullai A (2007)
In-situ phytoextraction of Ni by a native population of
Alyssum murale
on an ultramafi c site (Albania). Plant
Soil 293:79-89
Bañuelos GS (2000) Phytoextraction of Se from soils irri-
gated with selenium-laden effl uent. Plant Soil
224:251-258
Blaylock MJ, Huang JW (2000) Phytoextraction of met-
als. In: Raskin I, Ensley BD (eds) Phytoremediation of
toxic metals: using plants to clean up the environment.
Wiley, New York, pp 53-70
Blaylock MJ, Salt DE, Dushenkov S, Zakharova O,
Gussman C (1997) Enhanced accumulation of Pb in
Indian mustard by soil-applied chelating agents.
Environ Sci Technol 31:860-865
Boyd RS, Jaffré T (2001) Phytoenrichment of soil Ni con-
tent by
Sebertia acuminata
in New Caledonia and the
concept of elemental allelopathy. S Afr J Sci
97:535-538
Bridgwater AV, Meier D, Radlein D (1999) An overview
of fast pyrolysis of biomass. Org Geochem
30:1479-1493
Brooks RR, Chambers MF, Nicks LJ, Robinson BH
(1998) Phytomining. Trends Plant Sci 3:359-362
Chaney RL, Malik M, Li YM, Brown SL, Brewer EP,
Angle JS, Baker AJM (1997) Phytoremediation of soil
metals. Curr Opin Biotechnol 8:279-284
9
Conclusion and Future
Prospects
The success of a phytoremediation technique is
largely dependent on the continuous metal avail-
ability that concerns the plants. It appears attrac-
tive because in contrast to most other remediation
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