Metals phytoremediation

Metal removal in SSFCWs has been recently focused on metal elimination from synthetic water and different wastewaters,66-86 on the evaluation of the effects of season, temperature, plant species, and chemical oxygen demand (COD) loading on metals removal,87 and on the accumulation of metals in wetland plant species and sediments.88-89 Recent reviews on heavy metal phytoremediation wetlands are also available.48... 

Liao, S.W. and Chang, N.L., Heavy metal phytoremediation by water hyacinth at constructed wetlands in Taiwan, Journal of Aquatic Plant Management, 42, 60-68, 2004. 

Galiulin, R.F, Bashkin, V.N, Galiulina, R.R and Birch, P. (2001). A Critical Review Protection from Pollution by Heavy Metals — Phytoremediation of Industrial Wastewater. Land Contamination Reclamation, 9(4), 349-357... 

There is now considerable interest in the area of metal transport in plants because of the implications for phytoremediation -the use of plants to extract, sequester, and/ or detoxify pollutants such as toxic metals. Phytoremediation strategies for radionuclide and heavy metal pollutants focus on hyperaccumulation above ground. Significant progress has been made in recent years in developing native or genetically modified plants for the remediation of environmental contaminants (Meagher 2000). 

The phytofiltration of Pb(II) and Cd(II) has been also studied using species of Salvinia. S. minima Baker is a small free-floating aquatic fern native to Mexico, Central America and South America. It has been proved to be an excellent aquatic phytoremediator and hyperaccumulator of Cd(II) and Pb(II).72,76 The relevance of using a compartmentalization analysis (CA) complementary to the use of BCFs and metal removal kinetics by plants has been demonstrated using S. minima... 

In natural conditions, Ceratophyllum demersum and Potamogeton pectinatus L. have been found to be effective adsorbents of Cd(II), Cu(II), and Pb(II). The adsorption percentage of the metals onto plant surfaces followed the pattern Pb(II) > Cu(II) > Cd(II). P. pectinatus biomass adsorbed a higher content of heavy metals than C. demersum. According to the results, both species are of interest in the phytoremediation and biomonitoring studies of polluted waters.122... 

Padmavathiamma, P.K. and Li, L.Y., Phytoremediation technology Hyper-accumulation metals in plants, Water, Air, and Soil Pollution, 184, 105-126, 2007. 

Prasad, M.N.V., Phytoremediation of metal-polluted ecosystems Hype for commercialization, Russian... 

Dushenkov, S. and Kapulnik, Y., Phytofiltration of metals, in Phytoremediation of Toxic Metals Using Plants to Clean Up the Environment, Raskin, I. and Ensley, B.D., Ed. Wiley-Interscience, New York, 2000, pp. 89-106. 

Rai, P.K., Heavy metal pollution in aquatic ecosystems and its phytoremediation using wetland plants An ecosustainable approach, International Journal of Phytoremediation, 10, 133-160, 2008a. 

Fritioff, A. and Greger, M., Aquatic and terrestrial plant species with potential to remove heavy metals from stormwater, International Journal of Phytoremediation, 5 (3), 211-224, 2003. 

Weis, J.S. and Weis, P., Metal uptake, transport and release by wetlands plants implication for phytoremediation and restoration, Environment International, 30 (5), 739-753, 2004. 

A method for estimating the TSCF for equation 14.24 is given in Table 14.10. The root concentration factor is also defined in Table 14.10 as the ratio of the contaminant in the roots to the concentration dissolved in the soil water (pg/kg root per pg/L). This is important in estimating the mass of contaminant sorbed to roots in phytoremediation systems. The values of TSCF and RCF for metals depend on the metals redox states and chemical speciation in soil and groundwater. 

Salt, D.E., Blaylock, M., Nanda Kumar, P.B.A., Dushenkov, V., Ensley, B.D., Chet, I. and Raskin, I., Phytoremediation A novel strategy for the removal of toxic metals from the environment using plants, Biotechnology, 13, 468-474, 1995. 

However, some plants can accumulate more than 0.1% of Pb, Co, Cr, and more than 1% of Mn, Ni and Zn in the shoots. These accumulator plants are called hyperaccumulators. To date, there are approximately 400 known metal hyperaccumulator plants in the world (Baker and Walker, 1989). Thlaspi caerulescens, Alyssum murale, A. lesbiacum, A. tenium are Zn and Cd hyperaccumulators. Brassica juncea, a high-biomass plant, can accumulate Pb, Cr(III), Cd, Cu, Ni, Zn, Sr, B and Se. Thlaspi caerulescens accumulates Ni. Hybrid poplar trees are reported to phytoremediate Cd and As contaminated soils. A Chinese brake fem, Pteris vittata, is an As hyperaccumulator (Ma et al., 2001). 

Raskin I., Ensley B.D. Phytoremediation of Toxic Metals Using Plants to Clean the Environment. New York John Wiley Sons Inc, 2000. 

Phytoremediation (see also grass strips) Aesthetic improvement Cleans soil, water and air Decreases pollutant bioavailability Decreases pollutant toxicity Decreases pollutant concentration Degrades organic pollutants Extracts metals from soils Low-cost remediation Socially-acceptable reclamation Al-Najar et al. (2005) Babula et al. (2009) Baraud et al. (2005) Harvey et al. (2002) Joner and Leyval (2009) Khan et al. (2009b) Morel et al. (1999) Rodriguez et al. (2005) Scholz et al. (2009) Wahid et al. (2009)... 

Species firom this family are often found on salt or heavy metal polluted sites. Since they accumulate little biomass they are not used for phytoremediation, but their presence is taken as an indicator of pollution. 

Fast-growing and high-biomass-accumulating varieties can grow up to 2m in height, and these are suitable for the phytoremediation of salt, heavy metal or both. 

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