mercury quicksilver parsons m.b. & percival, j.b. (2005): mercury sources measurements cycles...

MercuryQuicksilver

Parsons M.B. & Percival, J.B. (2005): Mercury Sources measurements cycles

and effects MAC Short Course 34 Halifax

Chemicaland physical properties of

mercury

Historical Uses• Since 4000 BCE Cinnabar used for the preservation of human bones including

Egyptians• Since Egyptian/Roman times cinnabar used as paint pigment, cosmetic, pottery glaze,

anti fouling on ships, red ink. • Romans: Extraction of elemental Hg by distillation and amalgamation with gold• Middle ages: Hg amalgamation used in alchemy and early chemistry leading to the

discovery of 22 elements• Medicinal use since 460 BCE (Hippocrates) and since 16th century as a cure for

syphilis, and as a diuretic, antiseptic, contraceptive• Still used in dental amalgam, preservative in flu vaccines (Thimerosal), herbal

remedies

Industrial Use

• Chor-alkali process: Hg cathode in electrolytic production of NaOH and Cl from NaCl

• Pulp and paper industry (production of Cl)• Insecticides, herbicides, fungicides, bactericides; some

with very toxic alkyl mercury• Pendulum clocks• Thermometers, barometers, blood pressure gages• Electronics industry• Vacuum pumps• Liquid mirror telescope (rotating mercury produces a

perfect parabola)• Switches, thermostats, florescent lamps, batteries,

computers• Extraction of gold and silver

Toxicity

• Knowledge of toxicity from miners. Roman slaves and Spanish convicts had an average life expectancy in the Hg mines of 3 years

• Causes loss of teeth, tremors, loss of strength, psychological problems.

• Mad Hatter disease due to use of mercuric nitrate in felting of fur for hats

• Methyl mercury extremely toxic

Minerals

Cinnabar HgS

Geological Formations

• Hydrothermal ore formation• Note the natural emissions of Hg to the atmosphere from volcanoes and fumaroles

Mining

• Cinnabar mined at Amaden Spain since 430 BCE.

• HgS heated to release elemental Hg as a gas which is condensed

Almeda Hg Mine Spain

• Continuous production for over 2000 years since Romans• Total production ~ 250,000 tons Hg, 1/3 of entire world production• During the Arab domination of Spain, The Moors operated the mine during

between the 8th and 13th centuries.  Hg used in medicine and alchemy. • 12th century: mine 450 m deep with >1,000 workers. • 13th century Almadén was recaptured and held by Spanish Christians.• 16th century: amalgamation to extract gold and the silver discovered

causing major expansion of mine.• 16th and 17th centuries, most Hg was sent to Seville for American gold

extraction. • From 17th century, production reduced due to exhaustion of near surface

ore. • January 1755, a fire burned in the mines for >2 years, killing many people.• Early 19th century, labor problems due to the bad Spanish economy. • 1835 mercury was auctioned in London and mine economy improved. • 1916, special Council created for operation of the mines; technical and

safety improvements introduced. • 1941 After the Spanish Civil War, record production; 82,000 Hg flasks. • 1981 the Spanish government created the company Minas de Almadén y

Arrayanes, S.A. to operate the mine. 

Environmental Issues related to Hg Mining

• Secondary minerals – In roasted ore (calcines) 10-1000 ppm Hg, mostly metacinnabar– Forming in condensers, 100-10,000 ppm Hg, must be removed by

hand and discarded in tailings

• Waste Rocks and low grade ore• Emissions: adjacent soils have 10’s ppm Hg• Runoff from mine site and waste dumps are often adjacent

to streams• Wind blown particles, fine particles of calcine have high Hg• Mine drainage: open pit and underground

Rathburn –Petray Hg Mine, Cashe Creek, CA

• Worked prior to 1892, greatest activity between 1892 and 1893 for use in gold mining operations in California. Minor production in 1960's and 1970's.

• Hg-bearing material exposed in cuts, slopes, open pits, mine waste piles, and storm water retention ponds.

• Ash from a brick retort contains elevated levels of mercury.

• Waste piles contain approximately 101,500 m3 Hg-bearing material.

• Surface water runoff during storm events erodes waste and tailings piles, overflows retention ponds, and transports Hg-laden sediment into tributaries of Cashe Creek. Contributes 6.8 to 53.1 kg/year Hg

Anthropogenic sources now

Coal, Oil and gas