2 Factors Affecting the Uptake Mechanisms
The uptake, accumulation, and distribution of heavy metals in the plant depend on
the plant used for phytoremediation, element species which is being taken up,
temperature, dissolved oxygen, chemical and bioavailiability, cation exchange
capacity, redox potential, pH, and secretion by roots [76]. The uptake of a contaminant is greatly affected by the characteristics of plant species. Therefore, the plant
species with superior remediation properties are to be selected after screening. It is
important to choose a plant species that can efficiently hyperaccumulate heavy
metals and which yields large amount of biomass. A plant which is able to accumulate the heavy metal more than 0.1% in its dry weight is a hyperaccumulator
[77]. Meagher [78] has defined that any plant which has the ability to remediate
the soil by reducing the contaminant level by 50% in 24 h is termed as a good
phytoremediation agent. It is essential that along with the ability to bioaccumulate
the metal, the hyperaccumulator should have a tolerance to the heavy metal.
Hyperaccumulators should have the metal concentration of 1% for Mn and Zn;
0.1% for metals such as Al, Cr, Co, Cu, Pb, and Ni; 0.01% for Cd and Se; and
0.001% for Hg of the shoot dry weight [79]. The plants from family of Brassicaceae,
Cunoniaceae, Caryophyllaceae, Asteraceae, Euphorbiaceae, Cyperaceae,
Fabaceae, Lamiaceae, Violaceae, Poaceae, etc. [19], Alyssum species, Thlaspi
species, Brassica juncea, Viola calaminaria, and Astragalus racemosus take up
heavy metals and radionuclides in high concentrations [19, 80, 81]. Table 1 presents
some of the plants used in phytoremediation.
Fig. 5 Phytovolatilization
56
S. Sophia and V. Shetty Kodialbail
The uptake, accumulation, and distribution of heavy metals in the plant depend on
the plant used for phytoremediation, element species which is being taken up,
temperature, dissolved oxygen, chemical and bioavailiability, cation exchange
capacity, redox potential, pH, and secretion by roots [76]. The uptake of a contaminant is greatly affected by the characteristics of plant species. Therefore, the plant
species with superior remediation properties are to be selected after screening. It is
important to choose a plant species that can efficiently hyperaccumulate heavy
metals and which yields large amount of biomass. A plant which is able to accumulate the heavy metal more than 0.1% in its dry weight is a hyperaccumulator
[77]. Meagher [78] has defined that any plant which has the ability to remediate
the soil by reducing the contaminant level by 50% in 24 h is termed as a good
phytoremediation agent. It is essential that along with the ability to bioaccumulate
the metal, the hyperaccumulator should have a tolerance to the heavy metal.
Hyperaccumulators should have the metal concentration of 1% for Mn and Zn;
0.1% for metals such as Al, Cr, Co, Cu, Pb, and Ni; 0.01% for Cd and Se; and
0.001% for Hg of the shoot dry weight [79]. The plants from family of Brassicaceae,
Cunoniaceae, Caryophyllaceae, Asteraceae, Euphorbiaceae, Cyperaceae,
Fabaceae, Lamiaceae, Violaceae, Poaceae, etc. [19], Alyssum species, Thlaspi
species, Brassica juncea, Viola calaminaria, and Astragalus racemosus take up
heavy metals and radionuclides in high concentrations [19, 80, 81]. Table 1 presents
some of the plants used in phytoremediation.
Fig. 5 Phytovolatilization
56
S. Sophia and V. Shetty Kodialbail