Mercury Flashcards
Where is mercury found
- rocks
- cinnabar
- background in soil, air and water
- gas emitted by volcanos
Increased since industrial revolution
Applications for mercury
Create mercury vapour
Base metal smelting and gold mining
HgS
Cinnabar (main mineral is mercury)
2/3 of total mercury emissions in US
Industry sectors
3 industrial categories responsible for mercury emissions
- medical waste incinerators
- municipal waste combusters
- coal-fired power plants
Which of the 3 industrial emitters of mercury has yet to significantly reduce their mercury emissions
Coal-fired power plants
2011 US EPA emission legislation to power plants
- 99% mercury prevented
- 88% reduction of acid gas
- 41% reduction of sulfur dioxide
Chemical forms of mercury
- elemental
- inorganic
- organic
Elemental mercury
Liquid metal
Inorganic mercury
- mercury chloride
- mercuric sulfide (cinnabar)
Organic mercury
- Methyl, ethyl, dimethyl mercury
- phenyl organic groups
Methylmercury
Mercury converted by bacteria in aquatic sediments
Biomagnifies in aquatic animals
Methylmercury
Percentage of absorption of methylmercury in GI tract
100%
Major source of organic mercury for humans
Methylmercury
How does mercury get into humans
- emitted in power plant
- precipitates back to earth
- aquatic bacteria convert to methylmercury
- fish accumulate methylmercury through food chain
- people eat fish
Reproductive neurotoxin that affects brain and CNS
Mercury
Greatest risk to mercury
Pregnant women, women of childbearing age, children
Fetal mercury dammage
Mercury can cross placenta and cause irreparable neurological damage to fetus
2001 mercury CDC study of women in US
1 in 10 women have high enough levels to cause neurological damage to children
Mass methylmercury poisoning incident
1971 Iraq poison grain disaster
Paresthesia, ataxia and vision loss
= (Numbness of skin and lack of muscle control)
symptoms in Iraqi grain disaster
Poison grain in Iraq
Grain treated with methymercury fungicide, not intended for human consumption, imported from Mexico and US
Death toll of 1971 Iraq poison grain disaster
459 people
Minamata disease
Neurological syndrome caused by severe mercury poisoning
Cause of Minamata disease in Japan
Release of methymercury in the industrial wastewater from the Chisso Corp. chemical factory accumulated in shellfish and fish
Death toll of Minamata disease in Japan
1,784 out of 2,265 victims
Cause of Minamata disease in Ontario First Nations People
Drygen Chemical Company dumped over 9,000kg of mercury into Wabigoon-English river system where it was converted to methylmercury by bacteria
More than 90% of which First Nations groups show signs of mercury poisioning in Ontario
Grassy Narrows and Whitedog
Dental amalgam
Dental filling made of liquid elemental mercury and allot of silver, tin and copper
What percentage of amalgam is mercury
50
Risk associated with amalgum fillings
Can release mercury vapor
Pros of dental amalgum
Strong, long-lasting and least expensive
FDS on dental amalgum
Safe for adults and children over 6
FDA recommendation for current amalgam fillings
If they are in good shape, keep them, because taking them off can release vapor
Health Canada estimation for amount of mercury released per day by amalgam fillings
3 millionths of a gram out of 9 millionths of a gram from all sources
