Mercury and crematorium chimneys
Article Abstract:
Metallic dental fillings are composed of a mixture of silver, copper, and tin amalgamated with metallic mercury. Although mercury is known to be toxic, there is little danger from properly prepared and handled dental amalgam. However, the question has now been raised whether cremation releases significant amounts of mercury into the atmosphere. If the average head in Great Britain contains five fillings made of amalgam, then about three grams of mercury content might be expected to be emitted upon cremation. In burial, this mercury diffuses extremely slowly, and presumably harmlessly. However, during cremation much of this mercury could be evaporated in a short period and released into the atmosphere. A quick calculation reveals that a single crematorium might release as much as 11 kilograms of mercury per year into the environment. The safe upper limit for mercury in the atmosphere may be about one microgram per cubic meter. The mercury released during cremation could theoretically be trapped by activated charcoal in a chimney filter. It may be preferable to recover the filled teeth and recycle the mercury and silver. (Consumer Summary produced by Reliance Medical Information, Inc.)
Publication Name: Nature
Subject: Zoology and wildlife conservation
ISSN: 0028-0836
Year: 1990
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Stratification in poured granular heaps
Article Abstract:
It is possible for the stratification of poured granular mixtures into layers according to particle size to take place when there is no clear difference in particle shapes within the mixture. It has been established that stratification depends heavily on the fill rate, which determines the overall impact of the incident feed stream on the growing heap. If the angle of repose of the coarse grains is much larger than that of the fine grains, stratification will take place over a wide range of fill rates.
Publication Name: Nature
Subject: Zoology and wildlife conservation
ISSN: 0028-0836
Year: 1998
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Another green world: there's more to industrial waste than chimneys and slag heaps
Article Abstract:
A short story describes what could happen in the future if the faulty results of plant cloning experiments are unleashed into the environment.
Publication Name: Nature
Subject: Zoology and wildlife conservation
ISSN: 0028-0836
Year: 2000
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