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Phytoremediation: Green Technology is Put to the Test (Seminar)

April 28, 2008

12pm to 1pm

Seminar Details Canada has a legacy of industrial brownfields and other contaminated sites that are detrimentally affecting ecosystems and limiting land use. Many of these sites are contaminated with chlorinated organic compounds. Organochlorines (OCs) are persistent in the environment, are commonly toxic, and their presence in soils can dramatically reduce property values and hinder redevelopment efforts. In the last decade, the search for alternatives to existing and typically very expensive environmental remediation technologies has been intensifying. Consequently, there has been increasing interest in the development of ‘green’ or plant-based methods to remediate contaminated sites.

Phytoremediation is a plant-based technology that encompasses a number of different processes including extraction, degradation, stabilization, and volatilization of contaminants. Phytoextraction refers specifically to the process whereby contaminants are taken up by plant roots, translocated to the shoots via normal physiological processes of root pressure and leaf transpiration, and then sequestered in the above-ground plant tissues. Plants must then be harvested and undergo biomass reduction (e.g. composting), with the goal being to significantly reduce the total volume of contaminated waste, leaving the soil matrix intact. While heavy metal extraction by plants has been extensively studied, the potential to phytoextract OCs has not yet received much attention. Preliminary work on OC extraction has been promising with both greenhouse and pilot-scale field studies indicating that plants are indeed capable of taking up significant levels of polychlorinated biphenyls (PCBs) and dichlorodiphenyl-trichloroethane (DDT). This presentation will describe the current state of phytoremediation technology in Canada and present some recent greenhouse and field studies on OC phytoextraction using a number of targeted plants as well as native colonizers.  

Lecturer Dr. Barbara Zeeb received her PhD from Queen’s University, Canada in 1994. She joined the Environmental Sciences Group (ESG) at the Royal Military College of Canada (RMC) in 1996 to co-ordinate/manage environmental research projects, at numerous active and abandoned military installations across Canada. Since 1999, Dr. Zeeb has been involved in studies to phytoremediate heavy metals, including Canada’s largest demonstration project for utilizing plants to clean-up lead-contaminated soils in Chilliwack, BC. Dr. Zeeb’s current work has turned to the phytoextraction of organochlorines (e.g. PCBs and DDT), a particularly challenging process due to the hydrophobic nature of these contaminants. In the field and greenhouse her current objectives are to: i) elucidate the processes by which organochlorines enter plant tissues and are translocated from root to shoot material, ii) to evaluate and optimize the phytoextraction performance of pumpkin, sedge, and tall fescue in realistic field conditions, and iii) to assess the phytoextraction potential of various native colonizer species at the field sites. Working with government agencies (Environment Canada, Ministry of Natural Resources, and US EPA), and contaminated site owners (e.g. Dow Chemical), a realistic picture of the benefits (and potential pitfalls) of this biotechnology can be elucidated. In January 2004 Dr. Zeeb was awarded a Canada Research Chair in Biotechnologies and the Environment at RMC in the Department of Chemistry and Chemical Engineering, as well as a Canada Foundation for Innovation Award to fund the creation of her analytical laboratory. In 2007 she was awarded a Collaborative Research and Development grant to further her laboratory and field research on the phytoextraction of organochlorines. Dr. Zeeb is also an Adjunct Professor in the Department of Biology at Queen’s University, Canada and on two occasions she has participated in teaching mini-courses on phytoremediation to researchers and land owners in Eastern Europe.  

Location At the Botanical Garden Reception Centre, near the main entrance (Directions to the Botanical Garden)  

Cost Free  

Please Note Bring a bag lunch. Coffee supplied. Please call 604-822-3928 in advance to book a seat.