Transcript Slide 1
Daren Many & Natalie Gordon BZ 572 The World’s Worst Pollution Problems – The Top Ten of the Toxic Twenty (2008) Indoor Air Pollution Industrial Mining Activities Urban Air Quality Metals smelting and Untreated Sewage processing Radioactive Waste and Uranium Mining Used Lead Acid Battery Recycling Groundwater Contamination Contaminated Surface Water Artisanal Gold Mining Source: BlacksmithInstitute.org Amalgamation Separation Decomposition Gold Melting Photo credit: David Cleary Amalgamation Spillage Separation Residual Hg Discharge Decomposition Release of vapors Gold Melting Release of vapors What is Mercury (Hg) Three forms: • Elemental mercury (Hg(0)) – liquid or vapor form • Ionic Salts – mercurous (I) or mercuric (II) states • Organometallic compound - methylmercury Elemental Hg converted to Methyl Mercury through oxidation and methylation. Hg (0) Hg (II) Methyl Hg Biggest challenge with small-scale mining: Mercury in the atmosphere and Mercury poisoning Entire families can inhale the Skin rash caused by handling inorganic mercury gaseous mercury Photo credit: Blacksmith Institute Current Mercury Pollution Remediation Practices Worldwide there are no real mercury pollution cleanups occurring due to a lack of funding and/or interest. Arabidopsis thaliana Liriodendron tulipifera Nicotiana tabacum Mercury transformed into less toxic form Genetic Engineering Volatized mercury will eventually be recycled Phytomining for Gold Studies being done to phytomine gold and extract Hg simultaneously using Canola. Adjuvants used to increase gold solubility and uptake Offsets expense of remediation Returns land to agriculture Adjuvants may mobilize elements into groundwater • Inert Covers • Reactive Covers Remove and Treat • Soil Vapour extraction • Reactive Walls • In-Situ Leaching • Chemical Immobilization • Water Interceptors • Phytoremediation • Wetlands Containment & Covering In-Situ Treatment Responses to Point Source Mercury Contamination • Physical Separation • Hydrometallurgical • Thermal Hinton et al., 2001 A hybrid approach: • Phytoremediation to volatilize mercury already in soil/water • Introduction of cleaner gold mining methods, including use of retorts • Education of miners on the proper use and handling of mercury and on better extraction options Anderson, Chris, Meech, John A.. (2002). Growing Gold: Using Metal Accumulating Plants to Produce Gold. Available: http://www.mining.ubc.ca/cerm3/growing%20metals.html. Blacksmith Institute. http://www.blacksmithinstitute.org/artisanal-gold-mining.html Blue, Lisa Y., Van Aelstyn, Mike A., Matlock, Matthew and Atwood, David A. 2008. Low-level mercury removal from groundwater using a synthetic chelating ligand. Water Research 42(8-9):2025-2028. Davila, J. 2009. Mercury reduction by bacteria isolated from informal mining zones. Advanced Materials Research 7173():637-640. Ebbs, Stephen D., Kolev, Spas D., Piccinin, Robert C.R., Woodrow, Ian E., Baker, Alan J.M.. (2010). Solubilization of heavy metals from gold ore by adjuvants used during gold phytomining. Minerals Engineering. 23 , p. 819-822. Elena Rodrigueza; Jason G. Parsonsb; Jose R. Peralta-Videab; Gustavo Cruz-Jimenezc; Jaime Romero-Gonzalezc; Blanca E. Sanchez-Salcidob; Geoffrey B. Saupeb; Maria Duarte-Gardead; Jorge L. Gardea-Torres. (2007). Potential of Chilopsis Linearis for Gold Phytomining: Using Xas to Determine Gold Reduction and Nanoparticle Formation Within Plant Tissues . 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Phytoremediation technology: hyper-accumulation metals in plants. Water, Air and Soil Pollution 184(1-4):105-126. Renault, S., Szczerski, C., Sailerova, E., Fedikow, M.A.F.. (2004). Phytoremediation and revegetation of mine tailings and bio-ore production: progress report on plant growth in amended tailings and metal accumulation in seedlings planted at Central Manitoba minesite.. Report of Activities. 1 (1), p257-261. Rugh, C., Meagher, R.B.. (2003). Phytoremediation Technologies. Available: http://rydberg.biology.colostate.edu/Phytoremediation/2003/Amy/phytoremediationtechnologies.html. Speigel, S. 2010. International guidelines on mercury management in small-scale gold mining. Journal of Cleaner Production 18(4):375-385. Veiga, Marcello M. and Hinton, Jennifer J. 2002. Abandoned artisanal gold mines in the Brazilian Amazon: a legacy of mercurypollution. Natural Resources Forum 26:15-26.