The exercise is being done because

• Mercury is the most toxic substance known to mankind.

• Routes of exposure are inhalation or absorption.

• Elemental and inorganic mercury are methylated through bacterial action.

• Amalgam fillings are the largest source of methyl mercury in non-industrial exposed population.

• Each sphygmomanometer (blood pressure equipment) has approximately 60 grams of mercury.

• Mercury vapours from dental amalgam are the most dangerous form of mercury.

• Mercury can pass the skin, blood, brain and the placenta barrier and cause devastating health effects.

• The present total global mercury emissions into the atmosphere are 5000 tonnes per year, of which 80% are of anthropogenic origin.

• There are indicators showing 0.5 - 3.0 times increase in the anthropogenic emissions of mercury since pre-industrial times.

Coal

• The mercury contents of fossil fuel such as coal are quite small but the burning of large quantities of fossil fuel constitute pollution hazard. The mercury content in coal depends on its origin and varies from 0.02 to 0.31ppm, averaging 0.11 ppm in Indian coals derived from various coal mines. Coal may contain mercury in various forms, which gets transformed into vapours when the combustion of coal takes place. It is estimated that the substantial amount of mercury emissions are generated from coal-fired power plants. The Coal combustion is responsible for more than 42% of mercury emissions in Eastern Africa, while about 40% mercury emissions from Soviet Union.

• The Indian coal does not contain much mercury; however there may be generation of mercury emissions due to traces of mercury present in the coal during combustion. The total coal consumption for energy production is expected to increase further because of capacity enhancement of thermal power in the country and hence the mercury emissions due to coal uses are liable to increase in future.

Mercury Thermometer

• Typical mercury based glass thermometer contains 0.5 to 3.0 gm of mercury, which is seldom recovered on breakage of thermometer, but mostly lost.

• Average monthly breakage rate of mercury based glass thermometer in a 300 bedded hospital is around 70.

• Hospitals having nursing schools attached to them, register a very high breakage rate (5-6 per ward/month).

• A major reason of breakage of clinical thermometers in wards is the instrument slipping out of the hand, while shaking it to bring the temperature down.

• Mercury thermometer breakage is seldom handled carefully. Some of the major ways in which spills are handled are: sweeping it down to the drain, collecting it in a container and discarding it along with garbage.

• Approximately one gram of mercury in a typical clinical thermometer is enough to contaminate water body with a surface area of about 20 acres, to the degree that the fishes inhabiting there would be unsafe to eat.