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Minamata Japan 1932-1965
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Methylmercury was relseased into the bay directly from a factory
observed neurological disease pathway through shell fish |
Ontatrio Minamata
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Three first nations communities exposed to mercury from industrial sources in 1970's
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Artisanal mining
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Informal mining methods by individuals or families using simple technologies
open pan heating |
Artisnal gold mining
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-informal mining where mercury gold mixture is heated in open pan releasing mercury vapours
- mercury is also released to river water and taken up by fish which may be eaten by local communities |
What are the most toxic forms of mercury
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Organically bound
methylmercury and diamethlmercury forms in sediments and soils, converted by bacteria |
Mercury toxicity
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Nerotoxin- effects young children and pregnant women
biomagnifies bioaccumulates |
Mercury sources
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Coal burining
chlor-alkai plants mercury mining gold mining hydroelectric reservoirs bacteria convert mercury to methylmercury |
Most common human exposure to mercury
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Through fish, fish tissue contain methmercury in tissue
consumption advisories are common because of this |
Most toxic form of arsenic
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Arsenic trioxide
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Giant gold mine NWT 1948-1999
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Arsenic and gold co-occur
roaster emmited arsenic trioxide and sulfur arsenic contaminated material disspersed in the area and leaking from underground storage |
Ekati Diamon mine NWT 1998-?
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Silt control problems because silt blocks the light in the lake
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Why are new mines cleaner?
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Tighter regulations
chaning public attitudes increases scientific understanding |
Economic copper mine ore %
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2-3%
diamond and gold less then 1% |
Chemical aspects of mine waste
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Waste rock
slag tailings |
Waste rock
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Is broken rock which was mined but not milled
volumetrically important open pit or underground |