Environmental mercury and man : a report of an Inter-departmental Working Group on Heavy Metals.

  • Great Britain. Inter-departmental Working Group on Heavy Metals.
Date:
1976
Catalogue details

Licence: Open Government Licence

Credit: Environmental mercury and man : a report of an Inter-departmental Working Group on Heavy Metals. Source: Wellcome Collection.

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    chlorine, which is vital to the maintenance of wholesome water and for produc- tion of some plastics, and caustic soda, which is an important chemical used in many other industries. The principal uses of mercury (and the figures for 1975) are: the chloralkali industry — 475 tonnes supplied, 283 tonnes used; primary batteries — 80 tonnes; paints — 34 tonnes; agriculture and related uses — 28 tonnes; dentistry — 30 tonnes; electrical and control instruments — 14 tonnes; catalysis — 11 tonnes; laboratory chemicals — 10 tonnes; pharmaceuticals — 2 tonnes; adhesives — 1 tonne; and miscellaneous uses such as in munitions, pigments, photography, fireworks, laboratory vacuum pumps and textile fungicides, which taken together total about 6 tonnes. Emissions 10. Each of the above uses can give rise to release of mercury to the environment. In addition, mercury occurs in trace quantities in fossil fuels, minerals and rocks and is therefore emitted during the combustion of coal, oil or fossil-fuel gas, the production of cement, and from metallurgical processes. Disposal of sewage sludges, which may contain mercury arising principally from industrial losses, also releases mercury to the environment. 11. The chloralkali industry was responsible in 1975 for emissions of about 18 tonnes of mercury to water, about 22 tonnes to the atmosphere (4 tonnes of which were in hydrogen gas burnt as a fuel), 1-4 tonnes in the caustic soda produced, and 73 tonnes in waste sludges. It was unable to account for 167 tonnes of mercury. 12. All the mercury in paint and adhesives can be considered as released into some part of the environment. The same may be true of the mercury used in catalysis and pharmaceuticals, but the quantity actually released from electrical applications and thermometers etc. is unknown. 13. The agricultural and related uses of mercury are primarily for cereal seed and sugar beet seed treatment, for control of diseases in brassicae, onions and sports turf, for treatment of fruit trees and for dipping seed potatoes and bulbs. Clearly, all of this mercury is irreversibly released into various parts of the environment and this has led to much investigation. What is important here is the extent to which these practices result, if at all, in enhanced availability of mercury to plants, animals or man. In general, the effect of the agricultural use of mercury is very small. Thus cereal seeds treated with mercury produce harvested grain containing only very small quantities of mercury (*< 0:1 ppm“); the spraying of fruit trees produces fruit with mean levels (<0-07 ppm) not very different from levels in unsprayed fruit (ca 0-005-0:04 ppm); and most crops grown on land treated with mercury-containing sewage sludge show only a minimal uptake of the additional mercury into their edible parts, even when mercury levels in the soil are 100 times the normal levels. t< means less than. *] ppm is one part per million.