Phytoremediation

Heavy metal soil contamination at 100 Landry Avenue in Ottawa dates back to when it was the site of a Dominion Bridge foundry. Conventional methods of remediating toxic metals contaminated soils rely on excavation and burial at hazardous waste sites at an average U.S. cost of $1 million per acre.  Large-scale excavation associated with these technologies results in long-term exposure to dust and other air pollutants.[1]  The greatest cancer risk at metals waste sites is from inhalation or ingestion of windblown dust, and groundwater contamination.[2]  Many abandoned industrial sites remain contaminated without even the distant prospect of remediation because cleanup is too costly with available technologies.[3]  Phytoremediation is a plant-based method of remediation that offers a viable, cost-effective, and environmentally sound alternative to conventional methodologies.

Current Site Topography:

Abandoned former industrial site soil is contaminated with heavy metals.

Proposed Site Measures (Year Zero):

Re-grade to accommodate site surface water and prevent percolation of contaminated leachate to groundwater.

Proposed Site Measures (One to Five Years):

Site is sown with the heavy metal hyper-accumulator Brassica Juncea (wild mustard) and irrigated to maximize growth and extraction of heavy metals from soil. The central graded depression is planted with a dense grove of hybrid poplars surrounded with an outer ring of slower-growing hardwood trees including maples. The poplar grove acts as a sponge and pump to maintain hydraulic control and retain contaminated leachate. The number of planting/growing seasons required is determined by soil contamination concentrations. Construction could start as early as six months after the first planting. Where toxic concentrations are high, remediation may take five years or more.

After Twenty Years…

Short-lived hybrid poplars die out and the site is left with a ring of hardwood trees around the site depression which has become a community park with a central storm water retention pond.


[1] Tucker, Robert K. and Judith Auer Shaw. “Phytoremediation and Public Acceptance”, Phytoremediation of Toxic Metals: Using Plants to Clean Up the Environment, Ilya Raskin and Burt D. Ensley, eds. (John Wiley & Sons, Inc.: New York, 2000), 33.
[2]Schnoor, Jerald L. “Phytostabilization of Metals Using Hybrid Poplars”, Phytoremediation of Toxic Metals: Using Plants to Clean Up the Environment, Ilya Raskin and Burt D. Ensley, eds. (John Wiley & Sons, Inc.: New York, 2000), 133.
[3] Raskin, Ilya and Burt D. Ensley. Phytoremediation of Toxic Metals: Using Plants to Clean Up the Environment, Ilya Raskin and Burt D. Ensley, eds. (John Wiley & Sons, Inc.: New York, 2000), ix.