phytoaccumulators, (2) enhancement of phytoremediation process by soil
amendments, (3) microbe-assisted phytoremediation and (4) genetic alterations in
plants used for remediation purposes (McGrath et al. 2002).
Use of Natural Phytoaccumulators There are about 400 plant species belonging
to 45 plant families known to be effectively used in remediation of polluted soil
(Ekta and Modi 2018). Some of the families are Asteraceae, Brassicaceae,
Convolvulaceae, Euphorbiaceae, Fabaceae, Lamiaceae, Poaceae and
Scrophulariaceae (Gautam and Agrawal, 2019; Ekta and Modi 2018). Plants such
as Ludwigia sp., Dracaena sp., Phragmites australis, Rhizophora mangle,
Sparganium sp., Aegiceras corniculatum, Cannabis sativa, Arrhenatherum elatius,
Arabidopsis halleri, Brassica sp., Corrigiola telephiifolia, Raphanus sativus,
Thlaspi caerulescens, Alyssum sp., Arabidopsis sp., Eichhornia crassipes, Salix
sp., Euphorbia sp., Helianthus annuus, Pteris vittata, Jatropha curcas, Populus
sp., Spartina maritima, Potamogeton pectinatus, Ricinus communis, Trifolium
alexandrinum, Zea mays, Spinacia oleracea, Verbascum speciosum, Vetiveria sp.,
Ambrosia artemisiifolia, Lycopersicon esculentum, etc. have very high
bioaccumulation potential for organic pollutants (POPs, PAHs and PCBs) and
heavy metals (Cd, Zn, As, Cu, Fe, Pb, Hg, Mn, Mg, Cr and Ni) in soil (Table 16.4).
Brassica juncea cultivar Pusa Bold grown in soil amended with cow dung
manure exhibited high potential towards extraction of Cu, Fe, Cd, Zn, Mn, Cu, Pb
and Cr when compared to the cultivar Kranti (Gautam and Agrawal 2019). A study
conducted by Gautam and Agrawal (2019) on the herbaceous community at abandoned red mud dumps showed that dominant species, viz. Brachiaria mutica,
Cynodon dactylon, Dactyloctenium aegyptium, Digitaria ischaemum, Digitaria
longiflora, Eragrostis cynosuroides, Launaea asplenifolia, Parthenium
hysterophorus, Sporobolus diander and Stylosanthes scabra (with high IVI),
exhibited high metal accumulation and tolerance capabilities. Plant species were
recommended to be used in sustainable phytomanagement of abandoned red mud
dumps.
Enhancement of Phytoremediation Using Soil Amendments Bioavailability of
pollutants in soil can be controlled by the amalgamation of either organic or
inorganic amendments. Organic amendments include animal manure, sewage
sludge, biochar, vegetative dry dust, bacteria and plant-growth promoting
rhizobacteria (PGPR), litter waste, woodchips, rice husks, straw, etc. (Gautam
et al. 2017; Wiszniewska et al. 2016). Inorganic amendments include bauxite
residue, fly ash, ethylenediaminetetraacetic acid (EDTA), oxides of iron and aluminium, silicon (Si), inorganic fertilizers, liming agents (calcium carbonate, CaCO 3 ; and
calcium oxide, CaO) and sulphur-containing compounds (hydrogen sulphide, H 2 S)
(Vu and Gowripalan 2018; Gautam and Agrawal 2017). Shrestha et al. (2019)
showed reduced phyto-uptake of metals (Zn, Cd, Pb, Co and Ni) by switchgrass
(Panicum virgatum) grown in soil amended with vermicompost, thermophilic compost and coconut coir. In a study conducted by Gautam and Agrawal (2017), sewage
sludge addition to soil (1:2 (w/w)) enhanced the uptake of Fe, Zn, Cu, Ni, Cr, Pb, Cd
16 Causes, Effects and Sustainable Approaches to Remediate Contaminated Soil
479
amendments, (3) microbe-assisted phytoremediation and (4) genetic alterations in
plants used for remediation purposes (McGrath et al. 2002).
Use of Natural Phytoaccumulators There are about 400 plant species belonging
to 45 plant families known to be effectively used in remediation of polluted soil
(Ekta and Modi 2018). Some of the families are Asteraceae, Brassicaceae,
Convolvulaceae, Euphorbiaceae, Fabaceae, Lamiaceae, Poaceae and
Scrophulariaceae (Gautam and Agrawal, 2019; Ekta and Modi 2018). Plants such
as Ludwigia sp., Dracaena sp., Phragmites australis, Rhizophora mangle,
Sparganium sp., Aegiceras corniculatum, Cannabis sativa, Arrhenatherum elatius,
Arabidopsis halleri, Brassica sp., Corrigiola telephiifolia, Raphanus sativus,
Thlaspi caerulescens, Alyssum sp., Arabidopsis sp., Eichhornia crassipes, Salix
sp., Euphorbia sp., Helianthus annuus, Pteris vittata, Jatropha curcas, Populus
sp., Spartina maritima, Potamogeton pectinatus, Ricinus communis, Trifolium
alexandrinum, Zea mays, Spinacia oleracea, Verbascum speciosum, Vetiveria sp.,
Ambrosia artemisiifolia, Lycopersicon esculentum, etc. have very high
bioaccumulation potential for organic pollutants (POPs, PAHs and PCBs) and
heavy metals (Cd, Zn, As, Cu, Fe, Pb, Hg, Mn, Mg, Cr and Ni) in soil (Table 16.4).
Brassica juncea cultivar Pusa Bold grown in soil amended with cow dung
manure exhibited high potential towards extraction of Cu, Fe, Cd, Zn, Mn, Cu, Pb
and Cr when compared to the cultivar Kranti (Gautam and Agrawal 2019). A study
conducted by Gautam and Agrawal (2019) on the herbaceous community at abandoned red mud dumps showed that dominant species, viz. Brachiaria mutica,
Cynodon dactylon, Dactyloctenium aegyptium, Digitaria ischaemum, Digitaria
longiflora, Eragrostis cynosuroides, Launaea asplenifolia, Parthenium
hysterophorus, Sporobolus diander and Stylosanthes scabra (with high IVI),
exhibited high metal accumulation and tolerance capabilities. Plant species were
recommended to be used in sustainable phytomanagement of abandoned red mud
dumps.
Enhancement of Phytoremediation Using Soil Amendments Bioavailability of
pollutants in soil can be controlled by the amalgamation of either organic or
inorganic amendments. Organic amendments include animal manure, sewage
sludge, biochar, vegetative dry dust, bacteria and plant-growth promoting
rhizobacteria (PGPR), litter waste, woodchips, rice husks, straw, etc. (Gautam
et al. 2017; Wiszniewska et al. 2016). Inorganic amendments include bauxite
residue, fly ash, ethylenediaminetetraacetic acid (EDTA), oxides of iron and aluminium, silicon (Si), inorganic fertilizers, liming agents (calcium carbonate, CaCO 3 ; and
calcium oxide, CaO) and sulphur-containing compounds (hydrogen sulphide, H 2 S)
(Vu and Gowripalan 2018; Gautam and Agrawal 2017). Shrestha et al. (2019)
showed reduced phyto-uptake of metals (Zn, Cd, Pb, Co and Ni) by switchgrass
(Panicum virgatum) grown in soil amended with vermicompost, thermophilic compost and coconut coir. In a study conducted by Gautam and Agrawal (2017), sewage
sludge addition to soil (1:2 (w/w)) enhanced the uptake of Fe, Zn, Cu, Ni, Cr, Pb, Cd
16 Causes, Effects and Sustainable Approaches to Remediate Contaminated Soil
479