Environmental Engineering Reference
In-Depth Information
Use of Indigenous Bacteria from Arsenic
Contaminated Soil for Arsenic Bioremediation
Ivy Mallick , Sk Tofajjen Hossain , Sangram Sinha ,
and Samir Kumar Mukherjee
Introduction
Arsenic (As) is a ubiquitous element found in the earth's crust. It is now ranked fi rst
in a list of 19 hazardous substances by the Agency for Toxic Substances and Disease
Registry and United States Environmental Protection Agency (Goering et al.
1999
;
Prerna et al.
2007
). Among different chemical forms of As in the environment, the
most often encountered toxic forms are arsenite [As(III)] and arsenate [As(V)]
(Buchet and Lauwerys
1981
; Leonard
1991
; Mukhopadhyay et al.
2002
). The abun-
dance of different arsenic forms and its mobility in soil depends on several factors
like pH, redox potential, presence of other elements, organic matter content, texture
and biotic functions therein (Woolson
1977
). When environmental conditions
change, the speciation and mobility of arsenic may also change. As(III) is more
toxic due to its affi nity to bind with functional groups, like SH
−
and imidazolium
nitrogens of different biomolecules including catalytic proteins (Krumova et al.
2008
). On the other hand, arsenate (AsO
4
3−
) mimics phosphate (PO
4
3−
); thus it
affects cell metabolism by interfering with phosphorylation processes (Tseng
2004
).
Due to irrigation of agricultural fi elds with As-contaminated groundwater, the
concentration of As is also being increased in the crop fi elds, thereby creating a
potential risk in lower Gangetic plain of Indian sub-continent (Rahman et al.
2007
,
2008
; Bhattacharya et al.
2009
) including the sampling site, a paddy fi eld of Nadia
district, West Bengal, India, where the level of arsenic is above 0.05 mg/l
(Bhattacharya et al.
2009
), a level that is much above the WHO's recommended
limit. To have an effective measure of increasing As pollution in the environment,
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