NWT RESEARCH DATABASE

Regions: Inuvialuit Settlement Region

Tags: contaminants, environmental assessment, petroleum industry

Objective(s): The purpose of the Unipkat I-22 Phase II Environmental Site Assessment is to identify contaminates and their concentrations, as well as to delineate the extent of any contamination at this historic drilling sump site.

Project Description: The purpose of the Unipkat I-22 Phase II Environmental Site Assessment is to identify contaminates and their concentrations, as well as to delineate the extent of any contamination at this historic drilling sump site. The Unipkat I-22 Phase II ESA is designed to gain the maximum amount of site data. Potential contaminants of concern will be identified during the historical file review, but it is anticipated that salts and perhaps hydrocarbons will be the contaminants of concern based on work at other sites. The Phase II ESA will involve the following activities: historical file review, site survey, deep soil sampling, groundwater monitoring well installation and groundwater sampling, surface and groundwater sampling, thermistor installation and thermal monitoring, benchmark installation and shoreline erosion measurements, surface water sampling and water body sediment sampling, vegetation sampling, annual groundwater, thermal regime and shoreline erosion monitoring. 1 - Historical File Review A historical file review will be conducted before commencing the fieldwork to determine site infrastructure locations, activity dates and possible contaminants of concern. 2 - Site Survey Prior to conducting site activities, the locations of former infrastructure at the site such as well centre, camp location, drilling fluid storage, sump locations and access roads will be identified and recorded. 3 - Deep Soil Sampling A drilling rig will be used to delineate the potential contaminants of concern at the site, as well as to identify the boundaries of the drilling and camp sump locations. Current plans are to use a lightweight drilling rig designed for low-impact projects. The drilling rig will be heli-portable and rubber track mounted. 4 - Groundwater Monitoring Well Installation Up to ten monitoring wells will be installed at the site in selected boreholes that were drilled to delineate potential contamination. The monitoring wells will allow the sampling of groundwater at the site (physical and chemical parameters) for the current year in the future. 5 - Groundwater Sampling Following the installation of the monitoring wells, groundwater samples will be collected using disposable Teflon bailers. Physical parameters including temperature, pH, conductivity and dissolved oxygen will be collected using field meters. Chemical parameters will be analyzed depending on the contaminants of concern identified in the historical file review. 6 - Thermistor Installation Thermal data will be collected to determine what effect, if any, the Mackenzie River may have on the drilling sump. Thermistors will be used to measure ground temperatures at specified depths. Thermistors will be installed in boreholes following the soil sampling program. The thermistor, which consists of a wire with evenly spaced beads, will be installed inside a solid PVC pipe. The thermistors will record temperature from the surface to a depth of 6 m. When thermistors are coupled with a datalogger, ground thermal regimes can be collected annually 7 - Benchmark Installation The Mackenzie River has been eroding the shoreline adjacent to the site. To measure the annual erosion, one benchmark will be installed at the site. The benchmark will be installed in the borehole located furthest from the river bank. The benchmark will consist of a 5 cm diameter steel pipe (4 meters long) filled with concrete. The benchmark will be flush with the ground surface, and will be marked with high visibility tape. The benchmark location will be recorded using a GPS. The distance from the benchmark to the shoreline will be measured and recorded during the internal site visit, and on future site visits. 8 - Surface Water Sampling Surface water bodies located onsite are shallow melt water ponds which do not contain fish. Surface water samples will be collected from standing water located on the site. Samples will be collected from the edges of the waterbodies. Approximately 5 to 10 samples will be collected. The samples will be analyzed for the contaminants of concern identified in the historical file review. 9 - Sediment Sampling Sediment samples will be collected from beds of the larger water bodies located on the site using a sediment corer. Sediments will be collected to a maximum depth of 1 meter. Sediments samples will be collected near the edge of the ponds. Approximately 10 sediment samples will be collected. 10 - Vegetation Sampling If it is determined necessary as a result of the historical file review and from site observations, vegetation samples may be collected and analyzed for suspected contaminants. Rare plant samples will not be collected. 11 - Annual Monitoring Shell will continue monitoring groundwater, soil temperature, and shoreline erosion for the next ten years at the Unipkat I-22 site. Access The crew will access the site daily form Inuvik by helicopter, likely a B2350 (A-Star). The helicopter will remain on site during the field activities. The drilling rig will be mobilized and demobilized between Inuvik and the site using a Bell 212 helicopter. Supplies will be transported to the existing airstrip at Camp Farewell using a Twin Otter aircraft and transported to site using the A-Star. Accommodation The field crew will be based in Inuvik and be transported to the site daily. Fuel Storage No fuel will be stored at the site and the helicopter will not be refueled at the site. Fuel for the drilling rig will be transported daily from Inuvik to the site in a 20 L container. A drip tray will be placed below the drilling rig during the evening when it is not in use. A spill kit will be located at the site during field activities. Water Requirements Bottled water from Inuvik will transported to the site daily for the field crew. No water will be required for the drilling operations. Distilled water will be brought to site and used to decontaminate sampling equipment. Waste Management and Wastewater Treatment and Disposal All waste will be removed from the site and transported to Inuvik for disposal at an approved site. Wastewater from cleaning the drill bit will be minimal. A decontamination bucket will be used during the cleaning. Large particles will be removed from the auger and disposed in the borehole. Where contamination is suspected, loose materials will be placed in a 20 L buckets for disposal at an approved waste disposal facility. Auger flights will then be sprayed with distilled water and brushed clean. Fieldwork will be conducted from September 04 to 30, 2007 at Unipkat I-22, which is located within the Inuvialuit Settlement Region along the eastern bank of Arvoknar Channel in the Mackenzie Delta, Northwest Territories (69o11’36.07”N 135o20’33.88”W).