PROCEEDINGS OF 1995 CANADIAN MERCURY NETWORK WORKSHOP

MERCURY IN ONTARIO: AN INVENTORY OF SOURCES, USES, AND RELEASES

S. Sang and B. Lourie

Pollution Probe, 12 Madison Avenue, Toronto, Ontario M5R 2S1 

     Mercury is a serious environmental problem for several reasons.
     Among these are mercury's ability to persist in the environment for
     a long period of time and its ability to bioaccumulate in aquatic
     food chains to the point that consumption of fish is hazardous to
     birds, mammals, and humans. Mercury is a neurotoxin which affects
     the central nervous system and can cause brain damage in young
     children and fetuses.
     
     Mercury has been identified as a candidate for ban or phase-out in
     the Great Lakes basin by Canadian federal and provincial governments
     as well as the United States Environmental Protection Agency
     (U.S.EPA) and the International Joint Commission.
     
     Mercury is released into the environment from natural and
     anthropogenic (human made) sources. In the United States atmospheric
     deposition of mercury from human activities, is the major source of
     mercury in lakes, soil, and vegetation. In Ontario, major sources of
     atmospheric mercury include the burning of fossil fuels, municipal
     waste incinerators, and probably landfill gases and contaminated
     soils. Municipal sewage treatment plants and direct industrial
     discharges are major sources of mercury loadings to Ontario water
     bodies. The total amount of anthropogenic mercury entering the
     environment from Ontario sources is at least 5,138 kg per year. This
     figure can be broken down into atmospheric emissions and discharges
     to water. The estimated total atmospheric mercury emissions from all
     sources in Ontario is 2,503 kg per year. An estimated 2,635 kg of
     mercury are released into water bodies through industrial and
     municipal sources. Major sources of mercury and the percentage of
     their contribution to total mercury released into the environment is
     summarized in Table I.
     
     Mercury is used directly as an added component in many consumer
     goods. A wide range of household products used daily contain
     mercury; certain batteries, fluorescent lamps, thermometers, and
     electrical switches are the most common products. The amount of
     mercury used in certain products has declined significantly over the
     past decade, most notably in paints and batteries and fluorescent
     lamps. For example the use of mercury in paints and alkaline
     batteries have declined to zero. Fluorescent lamp manufacturer have
     also gone through significant processes in order to enhance the
     lamps energy efficiency and to reduce the mercury content. These
     actions have two significant environmental benefits i) reduction in
     mercury contents of the lamps will reduce the risk of mercury
     directly entering the environment in large quantities during
     disposal of the spent lamps, and ii) increase energy efficiency
     reduces the amount of energy use, which in turn reduces mercury
     emissions from fossil fuel generating plants.
     
     Significant quantities of mercury are still used in many products we
     purchase. Mercury is still a major component of dental amalgam, used
     for dental restoration. Each year, an estimated 400 kg of mercury
     finds its way into the teeth of people living in Ontario or is
     disposed down the drains to municipal wastewater treatment plants.
     Despite the switch to non-mercury alternatives by some dentists,
     there has been little effort among the dental community to actively
     promote the alternatives, or to make people aware of the possibility
     of mercury vapour rising from the amalgam in the mouth.
     
     In addition to the deliberate use of mercury, a large amount of
     mercury enters the environment incidentally as a by-product of the
     services and products we purchase. For example, as a result of our
     electricity consumption in Ontario, large amounts of mercury are
     emitted from the coal-fired generating stations.
     
     Mercury is regulated both federally and provincially. The Ontario
     Environmental Protection Act (EPA) set limits on concentrations of
     mercury in air at the point of impingement, as well as in ambient
     air. The Ministry of Environment and Energy has a set of guidelines
     to limit mercury concentrations in water and in fish tissue while,
     similarly, Health Canada has set guidelines to limit the amount of
     mercury in fish tissue. Regulations are also in place restricting
     the use of mercury in children's toys and furniture.
     
     Given mercury's known toxicity and the fact that virtually every
     jurisdiction in the Great Lakes basin is seeking to eliminate or
     greatly reduce mercury use, it is clear that a detail phase-out or
     sunset strategy is required. Mercury phase-out and reduction
     strategies should be based on three methods: pollution prevention,
     incentive-based controls, and government regulations. Mercury
     elimination and reduction efforts through pollution prevention can
     be achieved by: eliminating or reducing mercury in products,
     switching to alternative products, and reducing mercury emissions
     associated with energy production.

Table 1. Total Mercury Release to the Great Lakes Basin and Percentage Contributed by Each Source.

Emission SourceMercury Emission to the Atomosphere (kg/year)Percent of Total Release Associated with Energy Production

Coal, Fossil Fuel Power Station
Coal, Coke Making Processes
Coal, other uses
Oil

426
306
30
274

8
6
1
5 Subtotal of Mercury Emission resulting from Energy Production103620 Incidental Release Resulting from Industrial Activities

Metal Mining
Cement Production
Lime Manufacturing
Carbon Black Manufacturing

284
300

-

6

6

Municipal Solid Waste Incineration
Discard of batteries(Mercury Oxide)
Fluorescent Lamps
Pigments
Switches
Sewage Sludge Incineration
Dental Practices
Hospitals
Hazardous Waste Incineration
Biomedical Waste Incineration
Cremation
Landfill gas
Fungicides volatilization
Contaminated Soil
2
1 Subtotal of Mercury Emission Resulting from Intentional Use of Mercury88617 Total Mercury Emission from all Sources
in Ontario2,50349 Mercury Sources in WaterMercury Loading kg/yearPercent of Total Release Municipal Sewage Treatment Plants (STPs)
Metal Mining Sector
Discharges to the Areas of Concern (STPs, Run-off, and Overflows)
Inorganic Chemical Sector
Iron and Steel Sector
Organic Chemical Sector
Others1587
553
297

98
56
44
1530
11
6

2
1
1

BACK TO *********************************************************************