Cleaning of Mercury Contamination in Gabraith Street in Squamish, B.C. Canada 8 March 2004 Presented by Lindsey Dunn Saleh Salim

Introduction n Canadian Occidental Petroleum Ltd. (COPL) operated chlor-alkali plant from n Property owned by BC Rail and BCR Properties Ltd., plant owned by FMC of Canada Ltd.

Location n The plant is located on Gabraith Street in Squamish British Columbia, Canada. n 45 acres just south of downtown Squamish n The property is enclosed by the Howe (South), Cattermole Creek (West), and Mamquam Blind Channel (East) n The soil on site is a dredged sediment over formal tidal floats and saltwater marches

Chlor-Alkali Processes n Caustic soda and chlorine are produced by the electrolysis of an aqueous solution of sodium chloride (brine) n Approximately 4.2% of mercury released in atmosphere from chlor-alkali n Due to environmental concerns, mercury processes since abandoned and ion-exchange membrane technology used

Source of Mercury Contamination n Plant discharged and spilled mercury into the land, water, and air as a result of plant processes. n “Old Lagoon” was named as it was a main discharge area for discharge sludge from wastewater treatment diluted with saltwater n From (pre-environmental standards) plant discharged 2-31 kg/day or ,000 kg/year of mercury into the environment n : 1 kg/day or 370 kg/year discharged

Resulting Contamination n On site: the soil contained 65,635 m 3 of waste with Hg levels > 2ppm, 22,905 m 3 of special waste (Hg >100 ppm), ground water found to have unacceptable Hg levels (>2ppm) –“Old Lagoon” held 36,000 m 3 of Hg contaminated sludge, half of which could be considered “special waste”, ground water held dissolved mercury at levels 100x standards) –Surface vegetation found to have elevated levels of mercury n Off site: High levels of Hg found in sedimentation of water ways Channel, Creek n Highest levels found in Mamaquam Blind Channel at SW corner of property near dock n Howe Sound lake bottom organisms, aquatic vegetation, and general aquatic life (fish, birds, crabs, ect) found to have mercury traces

Risks associated with Mercury n Mercury causes adverse effects to the human and environmental health n Mercury changes to methylmercury by a chemical reaction in organic environments n Methymercury then has the ability to bio-accumulate within a food chain where by humans are at the greatest risk as the rate in which mercury is removed from the body cannot match the rate in which it is ingested.

Problems due to Contamination n Canadian Occidental petroleum Ltd(COPL) forced to change name to Nexen n Nexen paid Millions n Site left unused n Over 1700 rails cars of contaminated soil shipped to landfill

Environmental Impacts n Kills Aquatic life n Destroys vegetation n Make land unusable n Effects can be seen in generations to come

Alternative Remediation Technique n Precipitate Flotation method n Causes heavy metals to precipitate with iron elements in soil n Completely leaves site pollutant free n Compact device allowing onsite cleaning up n Separates contaminates from soil, thus allowing soil to be buried back onsite

Remediation Efforts n COPL and BC Rail agreed to complete voluntary clean-up but never completed work n Mandatory remediation was then required to a depth of 3 m n Difficulties included the hydrostatigraphy, tidal influences, presence of surface impoundments in the form of effluent and peroxide ponds, hydroecolgocial complexity n Cost equal to $45 million n Carried out by Nexen Inc. (formally COPL)

Remediation Techniques n Ground water recovery and treatment n Contaminated soil and sludge excavation and stabilization n Soil Washing

Techniques Considered n Electrochemical Remediation Technologies (ECRTs) –Strong electrical current sent through ground to remove metals and mercury –Limited because not economical for large areas –Location concerns: If mercury were to be mobilized it could send a large amount of concentrated mercury directly into aquatic environment surrounding site

New Mercury Capturing Technique n Presented by Noram Engineering and Constructors Ltd at 2002 Remediation Technologies Symposium n Uses lignin derivatives and a flocculating agent to remove and stabilize metal contaminants from contaminated water n Uses a lignin-ferric absorbent material to capture and immobilize metals in soil

Groundwater Remediation n Technique similar to wastewater treatment of suspended soils n Lignin dissolved in captured groundwater so that it bonds to free mercury n Coagulate to form colloidal lignin-mercury particles n Ferric chloride added to flocculate the mix and cause mercury to fall out of suspension n Result is groundwater with Hg < 1  g/l and a non-leaching mercury sludge

Soil Remediation n Soil mixed with a solid ferric-lignin adsorbent n Absorbent captures mercury in order to stabilize and immobilize n Contaminated soil extracted and disposed

Current State n BC Rail transferred 71 acres, worth $35 million, of clean land to the town of Squamish n Waterfront property will be commercially and residentially developed in preparation of the 2010 Olympics which will be held in BC