Phytoremediation of Petroleum Hydrocarbon Impacted Soils at a Remote Abandoned Exploration Wellsite in the Sahtu Region, Northwest Territories

Sub-arctic remote locations pose a challenge for remediation of petroleum hydrocarbons.  Selecting the best method that considers and balances each of the social, economic and ecological factors that are associated with the problems can be difficult.  Cost and logistical difficulties with conventional remediation by hauling hydrocarbon impacted material off-site from an abandoned exploration well site in the Sahtu Region of the Northwest Territories (NT) led to the decision to remediate the soils on-site through the use of phytoremediation with plant growth-promoting rhizobacteria (PGPR).  PGPR perform many functions in the soil, e.g., increased nutrient uptake, enhanced germination and tolerance to toxic contaminants, which can lead to enhanced plant growth and subsequent breakdown of hydrocarbons in the soil.  The site was seeded in 2012 with an annual northern tolerant species mix and fertilized.  Biochar, a carbon-rich by-product of pyrolysis, was added to select grids to determine if a soil enhancing amendment would have a positive impact on soil fertility and stability in an otherwise inhospitable growing medium.  Results from 2012 show decreases in concentrations of benzene, toluene, ethylbenzene, xylene, F1 and F2 hydrocarbons. Remediation below guidelines is anticipated by the end of summer 2014.