Evaluation of the Soils Contamination by Explosives at CFB Chilliwack and CFAD Rocky Point

Abstract : Following the decision of closing CFB Chilliwack, a sampling campaign was performed to evaluate the contamination by explosives at different demolition ranges. Three ranges, including Slesse, Vokes and the Soowahlie Rocket and Grenade Ranges were sampled using the pre-screening immunoassay method but most of the collected soils and water samples were shipped to DREV for a thorough HPLC analysis. At the Slesse Range, the ion mobility spectrometry-based system developed by CPAD Technologies was evaluated and compared as a tool for the field screening of explosives in soils and water. The system worked but suffers strong limitations due to the quantity sampled and to the sensitivity of the detector. Most of the open detonation activities, including cratering, grenade, concrete, wood and steel cutting done at the ranges were evaluated and showed low levels of explosive contamination. Sampling from the White Phosphorus Burning Area revealed no contamination by explosives as expected. An exception was noted in the Ordnance Destruction Pits Area at Slesse Range where higher levels of contamination were observed. At CFAD Rocky Point, it was observed that the open burning of obsolete gun propellants is an incomplete process leading to residue accumulation and should be modified. Nitroglycerine analyses revealed important levels of contamination and heavy metals analyses showed lead concentrations higher than the level C threshold. Action is therefore required at that site. At the High Energy Open Detonation Site (Rocky Point), no contamination by explosives was found. Recommendations regarding all these sites were made.