Research

Stokes Point Contaminants Assessment

Rationale

Site of old barrel dump in 1990 where contamination was detected in 2000.

The Stokes Point Distant Early Warning (DEW) Line site was decommissioned and partially cleaned-up in the 1960s. An additional clean-up was conducted in 1992 when a North Warning Site was constructed at Stokes Point. Discussions with members of the Aklavik Hunters and Trappers Committee indicated that an old landfill adjacent to the site was not cleaned-up completely. A preliminary investigation at the site in 2000 indicated the presence of DDT, Petroleum Hydrocarbon and metal contaminants. A follow-up detailed soil and water sampling program was conducted in 2001. A strategy for cleaning-up the Stokes Point DEW Line site is being developed based on the results of this project.

Objectives

• To confirm the presence of contaminants found in 2001 at the Stokes Point DEW Line site.
• To determine how wide spread the contamination is.
• To describe the characteristics of the landfill.
• To develop a strategy for future clean-up operations at Stokes Point.

Methods and Information Collected

2000 Program

• Fifteen soil or stream sediment samples and three water samples were collected from the landfill site. The samples were selected based on the highest probability of detecting contaminants in the soils.
• Water samples were analysed for metals and PCBs.
• Soil samples were analysed for metals, PCBs, chlorinated pesticides, light and heavy extractable petroleum hydrocarbons and petroleum hydrocarbons (PCHs).
• Analysis was performed by Analytical Services Ltd. in Vancouver, BC.

2001 Program

• A 250 m baseline and grid was established over the entire landfill area.
• Ninety-six, 250 ml soil samples were collected and nine 2 litre water samples were collected in adjacent water courses.
• The soil samples were analysed using screening level field test kits (Petroflag and Immunoassay kits). All 96 samples were analysed for DDT and petroleum hydrocarbons (PCHs). Forty-seven samples were analysed for PCBs.
• The remaining samples are being stored for future metal analysis.

Results

Results 2000

• Four of 6 soil samples analysed for chlorinated pesticides showed DDT concentrations in excess of Canadian Council of Ministers of the Environment (CCME) soil guidelines of 0.7 ppm. One of these samples contained in excess of 70.0 ppm total DDT. Very high concentrations of antimony were observed in the same four samples.
• All 15 samples were analysed for metals. One sample exhibited metal contamination with elevated concentrations of arsenic, cadmium, chromium, lead, nickel and zinc.
• Various constituents of petroleum hydrocarbons were detected in 7 of nine soils samples analysed.
• PCBs were not detected in either soil or water.
• The water samples collected did not contain elevated concentrations of metals. They were not analysed for chlorinated pesticides or petroleum hydrocarbons.

Results 2001

• Analysis of soil samples provides semi-quantitative and qualitative results only. Concentrations are provided based upon a range determined by the calibrators. For DDT the calibrator ranges are 0.2, 1.0, and 10 ppm. For PCB the calibrator ranges are 1.0, 5.0, and 50.0 ppm. The field kits will detect a broad range of hydrocarbons up to 10,000 ppm.
• Two of 96 samples showed DDT concentrations between 0.2-1.0 ppm. Three samples showed detectable levels of DDT between 0.0-0.2 ppm. These samples are all close to the old landfill and the 2000 samples sites that contained DDT levels in excess of CCME guidelines of 0.7 ppm.
• Two of 47 samples analysed for PCB showed concentrations between 5.0-50.0 ppm. Four samples showed concentrations between 1.0-5.0 ppm. These sample sites are scattered throughout the sample area and suggest wide spread but possibly sporadic contamination in excess of CCME guidelines of 1.3 ppm.
• Six of 96 samples analysed for petroleum hydrocarbon constituents exhibited concentrations greater than 10,000 ppm. Eight samples showed concentrations between 1000-3000 ppm. All of these sites were concentrated around an old fuel barrel dump that was removed in 1992.
• Environment Canada in Burlington, Ontario is performing the water analysis.
• Analysis for metals will not be performed until funds are available.
• The concentrations of PCBs, DDTs and PCHs in soils from both the 2000 and 2001 sampling programs indicate the presence of contaminants associated with the old landfill. Many of the samples exceed Canadian CCME guidelines established for wildlands.
• Based on the results of this project, a strategy for cleaning-up the site will be developed.

Contacts

Angus Simpson
Senior Park Warden
Parks Canada Agency
P.O. Box 1840
Inuvik, NT
X0E 0T0
Phone: (867) 777-8815
Fax: (867) 777-8820
Angus_Simpson@pch.gc.ca

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