Evaluation of phytoextraction and biochar as a remedial approach for treating agricultural soils impacted with metals

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Contamination of agricultural soils with metals is a word wide problem. As a result of industrial processes and/or inappropriate disposal practices of metal-contaminated wastes, much of the arable land both in Canada and overseas has become essentially unusable. Traditional remediation methods to deal with metal contamination include excavation and landfilling, incineration, soil washing, solidification/stabilization, and vitrification. Although effective, these methods are costly and can negatively affect soil quality or result in its complete destruction. This research project assesses the feasibility of applying two complementary plant-based approaches (i.e. phytotechnologies) to remediate large tracts of agricultural land in China and Canada. In both cases, the soils cover a large area and are contaminated predominantly with cadmium, but also with other metals including nickel, copper, zinc, and lead. Phytoextraction refers to the use of vascular plants to extract soil contaminants into plant roots and translocate them to the shoots, which are then harvested, composted, and disposed of. This technology will be contrasted with the immobilization of metals in the soil matrix using biochar, a very stable form of organic matter, which also improves the soil quality. By simultaneously exploring the efficacy of using these two phytotechnologies to remediate metal-contaminated soils from agricultural areas near Hechi, Guanxi Province, China and Bolon, Ontario, Canada, Malroz Engineering Incorporated hope to discern the most important site-specific variables, and be able to apply the findings to other commercial sites. This alternative 'green technology' will be a convenient and cost-effective tool to add to Malroz's 'toolbox' of remediation technologies.