Page 200 - Plant-Based Remediation Processes

192 A. Branzini and M.S. Zubillaga

Table 10.1 Comparison between contamination levels in shoot/leaves and roots of Sesbania
virgata plants, when HM were added individually and in mixture
ANOVA (p values) Cu Zn Cr
Shoots and leaves 0.0042 0.0006 0.004
Roots <0.001 <0.001 <0.001
Contrasts
Shoots and leaves
Cu and Cu/Zn low vs. Cu and Cu/Zn high <0.001
Cu and Cu/Cr low vs. Cu and Cu/Cr high <0.001
Cr and Zn/Cr low vs. Cr and Zn/Cr high 0.0157
Roots
Cu and Cu/Zn low vs. Cu and Cu/Zn high 0.0025
Cu and Cu/Cr low vs. Cu and Cu/Cr high 0.0234
Zn and Cu/Zn low vs. Zn and Cu/Zn high 0.0002

Table 10.2 TF and BCF in different tissues of Sesbania virgata under soil HM treatments
Cu Zn Cr
Root Shoot Root Shoot Root Shoot
HM levels TF BCF BCF TF BCF BCF TF BCF BCF
Control 2.18 1.41 3.07 1.11 0.78 0.87 6.48 0.68 4.40
Cu Low 1.11 0.34 0.41
High 0.23 0.12 0.03
Zn Low 0.32 2.03 0.64
High 0.42 0.75 0.32
Cr Low 0.05 1.81 0.09
High 0.03 1.39 0.05
Cu/Zn Low 0.55 0.34 0.19 0.26 2.18 0.56
High 0.11 0.80 0.09 0.59 1.40 0.83
Cu/Cr Low 0.18 0.29 0.05 0.11 1.52 0.17
High 0.30 0.16 0.05 0.05 1.08 0.06
Zn/Cr Low 0.30 1.79 0.55 0.28 0.8 0.22
High 0.51 0.72 0.37 0.14 0.53 0.08
Note: TF Translocation factor, BCF Bioconcentration factor

the above- and underground part of the plants were <1.0 (Table 10.2). Therefore, all
heavy metals were accumulated in greater concentrations in plant roots. On the other
hand, the BCF average in roots was Zn (1.4) > Cr (1.1) > Cu (0.5), the roots being
more effective than shoots in accumulating heavy metals (Table 10.2). Similarly, to
that found by other authors, this seems to indicate that S. virgata would have a
higher bioaccumulation potential of Zn and that it is more effective in removing it
from soils (Zhang et al. 2010). Absorption and accumulation of heavy metals in
plant tissues depend upon many factors (Sarma 2011). A significant accumulation of
Cu, Zn, and Cr in the root system compared with the shoot parts of S. virgata may
indicate a higher efficiency in restraining the translocation and/or low capacity for
controlling their absorption, preventing them from reaching metabolically more