Environmental Engineering Reference
In-Depth Information
Fig. 8
Mine reclamation with selected native Thai plants (Prasad et al.
2014
)
4.1
Phosphate Fertilization
of Arsenic-Contaminated Soils
hybrid between American (
Tagetes erecta
L.)
and French (
Tagetes patula
) marigolds, are
potential candidates for fi eld remediation of
soils contaminated with As in Ron Phibun
District, Nakhon Si Thammarat Province, south-
ern Thailand ( Chintakovid 2008, Francesconi
et al.
2002
; Huq et al.
2005
). Marigolds have a
high potential for As phytoremediation being
nonedible and income generators. The waste
generated from such ornamentals after decay is
relatively easier to dispose off in secure landfi lls
(Prasad
2012
). These studies have provided
critical information for better understanding of
phytoremediation of As-contaminated soils in
Thailand.
Arsenic is toxic whereas phosphorus (P) is essen-
tial for plants. Phosphate is reported to suppress
plant uptake of arsenate. Studies have also shown
that at low levels, arsenate can increase phosphate
uptake (Cao et al.
2003
). They are both having
similar electron confi gurations and chemical prop-
erties. Therefore, arsenate and phosphate will com-
pete with each other for soil sorption sites, resulting
in a reduction in their sorption by soil and an
increase in solution concentrations. Phosphate
signifi cantly suppressed the sorption of arsenate.
Phosphate fertilization of As-contaminated soils
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