The manufacture of batteries represents another major market for mercury that is declining as manufacturers switch to alternative metals. Another major use for mercury is in electrical applications. Uses range from metallic mercury switches in thermostats to mercury-vapour discharge lamps. Other uses include mildew-proofing paint additives, dental amalgams, temperature and pressure measuring devices, detonators, pigments and pharmaceuticals.
Risks as a Cumulative Poison
Inorganic forms of mercury can be converted to more toxic organic forms (ie, methyl mercury) by chemical as well as biochemical (microbial) reactions. This conversion occurs primarily in aqueous sediments. Inorganic and organic mercury from both natural and synthetic sources can enter the food chain. Methyl mercury can become increasingly concentrated in the food cycle of aquatic life; it may reach dangerous levels in fish (see GRASSY NARROWS). Highly toxic levels can cause irreversible damage to the nervous system and the brain. The phrase "mad as a hatter" refers to the occupational disease resulting from contact with the mercury used in the early manufacture of felt hats. Increased concerns related to the risks of exposure on human health and the environment have led to increased restrictions on the uses of mercury; however, its unique properties will likely guarantee its presence in some key sectors for the foreseeable future.
Since the 1975 closure of Cominco Ltd's Pinchi Lake mine in BC, Canada no longer produces mercury metal. Mercury use in Canada and around the world continues to decline as environmental concerns increase. Spain is the world's largest producer of mercury, followed by Krygyzstan, Algeria and China. Approximately 60% of the mercury used in the world is recovered from primary sources.
Canadian consumption of mercury metal is primarily for applications in electrical apparatus, industrial and control instruments and for the electrolytic preparation of chlorine at the one remaining chlor-alkali plant for use in the pulp and paper industry in New Brunswick. Consumption for applications such as gold recovery, industrial chemicals, paints and pigments has been phased out in Canada.
Author P. CHEVALIER
Links to Other Sites
Life of a Rock Star
This site tells the story of an extraordinary group of scientists who tramped, paddled and rolled across Canada in the nineteenth century to study the geology of Canada's varied terrain.
A History of Mining and Mineral Exploration in Canada
Click on the cover image to view an online copy of a comprehensive report that traces the emergence of Canada's mineral industry. From Natural Resources Canada.
Climate change blamed for rising mercury levels in whales
A CBC News article about evidence of rising mercury levels in whales.
Mercury and Human Health
Information about sources of mercury in the environment, health effects of mercury exposure, the risks of mercury poisoning, and related issues. From Canada’s Minister of Health.
Grassy Narrows & Islington Band Mercury Disability Board
The website for the Grassy Narrows & Islington Band Mercury Disability Board. Provides information about determining eligibility for benefits, the nature of mercury poisoning, a history of mercury contamination in local communities, mercury levels in fish stocks, and related issues.