NWT RESEARCH DATABASE

Tags: contaminants, site remediation, biology, vegetation, botany, forestry, phytoremediation

Objective(s): The purpose of this study is to visit the Nota Creek C-17 wellsite and collect soil samples for phytoremediation bench top (laboratory and greenhouse) testing. The testing will confirm whether or not the wellsite is a suitable candidate for a pilot phytoremediation program. A small site planting may be completed as part of the screening process.

Project Description: The purpose of this study is to visit the Nota Creek C-17 wellsite and collect soil samples for phytoremediation bench top (laboratory and greenhouse) testing. The testing will confirm whether or not the wellsite is a suitable candidate for a pilot phytoremediation program. A small site planting may be completed as part of the screening process. Contamination issues were first identified on the dry and abandoned CDN Forest et al Nota Creek C-17 wellsite (Nota Creek C-17 wellsite) in August, 1998. Various efforts at remediation were initiated over the 1998 – 2004 timeframe with limited success. Examination of 2004 and 2006 sampling data confirms the presence of both petroleum hydrocarbon (PHC) and salt impacted soils on the wellsite. The significant volume of salt impacted soils is not only consequential to a successful remediation, but when coupled with the remoteness of the location it also limits the number of remedial options. Excavation and disposal of the impacted soils to an approved landfill in northern Alberta or British Columbia is an option but the associated cost premium is significant and transporting impacted material long distances on winter roads introduces a new element of risk to the situation. Phytoremediation, a relatively new technology, may provide the means for on-site remediation of the impacted soils. Phytoremediation is a remediation strategy involving the use of plants to remove contaminants, usually from polluted soil. Recently, this technology has been enhanced by combining conventional phytoremediation with root-associated bacteria. The bacteria provide effective partitioning of contaminants out of the soil and promote the growth of plants and roots. However, each phytoremediation candidate needs to be properly assessed and undergo detailed screening to determine its suitability for the technology. Bench top testing and pilot studies are often required. Pilot planting would be initiated on site once the Nota Creek C-17 wellsite is confirmed by bench top testing to be an acceptable candidate. Specific plant species will be used to facilitate the degradation of hydrocarbon and the uptake of salt. The plants would be harvested and burned at the end of each growing season, thus removing salt from the impacted soil. Yearly plantings would commence once the efficiency of the phytoremediation program is confirmed to be satisfactory and would continue until planted soil is remediated to applicable guidelines. Any impacted soil still buried would be excavated and spread on the wellsite. The phytoremediation process would then be repeated until all impacted soil is remediated. Personnel will visit the wellsite to collect soil samples. The personnel and sampling equipment (shovels, picks, hand augers, power auger and sample containers) will be transported to the site by helicopter from Norman Wells. Approximately 15 x 20 L plastic pails of salt impacted soils and 10 x 20 L plastic pails of control soil will be collected for phytoremediation testing. Other samples (.5 L) will be taken to further define the impacted soils. Additional ground water monitoring wells will also be installed during this visit. Should it be decided that a small site planting is beneficial to the screening process a garden tractor will be mobilized to the site by helicopter. Two or three trial plots (10m x 20m) will be cultivated and seeded to recommended plant species. The plots would be monitored and evaluated throughout the summer/fall. The plants would be harvested at the end of the growing season and the site assessed for phytoremediation efficiency. The garden tractor may be demobilized from the site in the fall or winterized on site to be available for future plantings. An interim progress report or summary report will be submitted to the Aurora Research Institute prior to Research Licence renewal in 2008. Both Indian and Northern Affairs Canada and Sahtu Land and Water Board personnel are aware of the phytoremediation pilot program proposal and will be kept apprised of the assessment progress. They will be forwarded copies of the progress and/or summary report as well. Fieldwork will be conducted from August 01 to October 15, 2007 at the Nota Creek C-17 wellsite, which is located at 65º06'01" N 126º02'58" W in the Sahtu Region of the Northwest Territories. The site is located approximately 43 kilometers southeast of Norman Wells and approximately 38 kilometers northwest of Tulita.