1. The Mercury Problem

Mercury occurs naturally in the environment; however, more than half of the mercury in the atmosphere today comes from human activities, such as the burning of coal, the smelting of metal, and the disposal and incineration of mercury-containing products. Common products that may contain mercury include fluorescent lamps, thermostats, temperature- and pressuremeasuring devices, dental amalgam, electrical switches, and relays.

In Canada, industrial releases of mercury have been substantially reduced since the 1970s, and the use of mercury in products has declined. However, products remain a significant source of mercury: for example, 10 milligrams of mercury, an amount that can be found in some fluorescent tubes, could contaminate up to 10,000 litres of water to levels that would exceed Health Canada maximum acceptable concentration for safe drinking water.

http://www.hc-sc.gc.ca/ewh-semt/pubs/water-eau
/guidelines_sixth-rec_e.html

Mercury can be carried on wind currents, remain in the atmosphere for a length of time anywhere from hours to years, and be deposited around the globe. Once in lakes and waterways, mercury can be transformed into a more toxic form called methyl mercury, which can build up in the bodies of living creatures. Methyl mercury levels can then increase up the food chain as creatures accumulate the methyl mercury that was in their food. This is most often seen in fish eaters, like swordfish, bass, walleye, loons, and otters. The severity of the effects on wildlife depends on the level of exposure and may range from a slight physical or behavioural impairment to reproductive failure or death.

The accumulation of methyl mercury in fish has led to fishing advisories across Canada. Currently, over 90% of advisories issued in Canada are due to mercury (see Mercury: Fishing for Answers for more information at http://www.ec.gc.ca/ceqg-rcqe/English/Pdf/mercury.pdf), and there is particular concern for subsistence fishers who eat large quantities of fish as part of their traditional lifestyles.

In general, mercury can cause brain, nerve, kidney, and lung damage and, in extreme cases, coma or death. Children who have been exposed to very low levels of mercury while in the womb can experience developmental effects. Typical sources of mercury exposure for humans are dental amalgam fillings and eating contaminated fish. In some cases, exposure can also result from mercury-containing products.

Managing mercury-containing products at federal facilities can help reduce mercury releases, occupational exposure, and the chance of mercury spills, and can help prevent impacts on human and environmental health. Environment Canada Mercury and the Environment web site (http://www.ec.gc.ca/MERCURY) provides more information on the sources and effects of mercury in addition to instructions for cleaning up small mercury spills; mercury-related legislation, policies, and initiatives; and fish consumption advisories.