Phytoremediation Towards the Future: Focus on Bioavailable Contaminants
The hypothesis that one of the possible future trends of phytoextraction should be the removal of the bioavailable contaminants has recently received renewed and increasing interest. This fraction is the most hazardous to the environment and human health.
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Phytoremediation Towards the Future: Focus on Bioavailable Contaminants Gianniantonio Petruzzelli, Francesca Pedron, Irene Rosellini, and Meri Barbafieri
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Introduction
The term phytoremediation refers to a set of technologies that employ plants for soil, sediment and contaminated water remediation. Due to their simplicity, low cost and, above all, environmental benefits, phytotechnologies have raised considerable interest since 1990s for in situ remediation of contaminated soils. Of these techniques, metal phytoextraction is, at least theoretically, a brilliant strategy for the biological remediation of nonbiodegradable contaminants. Phytoextraction and all other phytotechnologies have been extensively examined, discussed, and applied, and overall emerging framework has shown some positive results—along with several limitations, i.e., the need for further efforts to make them more efficient. In fact, there is a noticeable discrepancy between the number of scientific papers based on laboratory tests and the results achieved from concrete cleaning operations (Robinson et al. 2006). While the scientific community has found a challenging area of research, the field application of these technologies has encountered several difficulties that are often underestimated in theoretical studies. The results from experiments in hydroponics or in uncontaminated soils spiked with pollutants, although scientifically valid, do not reproduce the real conditions of contamination. Increasing concern derived from the differences between expectations resulting from the theoretical data and the practical realization of remediation have led to the conclusion that phytoextraction is not feasible in practice. This is due to the length of time required for remediation, and the difficulty in obtaining a high biomass production with high metal concentrations (Ernst 2005; McGrath et al. 2006; Robinson et al. 2006; Van Nevel et al. 2007).
G. Petruzzelli • F. Pedron • I. Rosellini • M. Barbafieri (*) National Research Council — Institute of Ecosystem Studies, Section of Pisa, Via Moruzzi 1, 56124 Pisa, Italy e-mail: [email protected] D.K. Gupta (ed.), Plant-Based Remediation Processes, Soil Biology 35, DOI 10.1007/978-3-642-35564-6_13, # Springer-Verlag Berlin Heidelberg 2013
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However, this conclusion is not completely true since some metals, such as nickel phytoextraction, have been employed with great efficiency (Ghaderian et al. 2007). In some cases, technology also provides positive results with nonhyperaccumulator plants (Pedron et al. 2009; Koopmans et al. 2007). These successes derive, above all from the characteristics of contaminated soils, for instance, the pH that determines both the bioavailability of the contaminants and the conditions necessary for plant growth. Soil properties are the key to phytoextraction efficiency, but often they are not fully considered in the selection of the technology. Soils undergo physical, chemical, and biological reactions that continuously distribute m
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