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Environmental Science PowerPoint Lecture Principles of Environmental Science - Inquiry and Applications, 2nd Edition by William and Mary Ann Cunningham Chapter 11 familiarize you with: •Understand some basic geologic principles, including how plate-tectonic movements affect conditions for life on earth •Explain how the three major rock types form and how the rock cycle works •Summarize economic mineralogy, strategic minerals •Discuss environmental effects of mining and mineral processing •Recognize geologic hazards: earthquakes, volcanoes, floods, and erosions Key Terms – Chapter 11 •Barrier islands •Metamorphic rocks •Core •Midocean ridges •Crust •Mineral •Earthquakes •Flood •Floodplains •Heap-leach extraction •Igneous rocks •Landslides •Magma •Mantle •Rock •Rock cycle •Sedimentary rocks •Sedimentation •Smelting •Strategic metals & minerals •Tectonic plates •Volcanoes •Weathering Chapter 11 - Topics • • A Dynamic Planet Minerals and Rocks • Economic Geology and Mineralogy • Environmental Effects of Resource Extraction • Conserving Geologic Resources • Geologic Hazards Part 3: Economic Geology and Mineralogy • Economic mineralogy = the study of minerals that are valuable for manufacturing and trade (most metal ores); need economically recoverable levels (non-metal geologic resources – graphite, feldspar, quartz crystals, diamonds) • Public policy in the U.S. has encouraged mining on public lands as a way of boosting the economy and utilizing natural resources Living things C, N, O, H Atmosphere C, N, O, Earth, rocks Economic metals O, Ar, Ne, He Al, Fe, Ni, Si, Mg, Ca, Na Al, Fe, Ni, Cr, Cu, Pb, Mn Ni, Primary toxins Pb, Hg, Se, Br, Cd, Be, Rn, As Fe used most followed by Al What common - living things, atmosphere, earth, rocks? Are any economic metals important for living things? O NO What elements are common between atmospheric element & economic metals? None What elements common between earth & economic metals? Pb, Ni Al Fe Ni What common elements for economic metals & primary toxins? Metals consumed in highest quantity globally • Iron (most consumed) > aluminum > manganese > copper > chromium > nickel [earths crust = 8.2% Al, 5.8% Fe] • Most metals consumed in the following order of highest consumption = US > Japan > Europe • Most metals produced primarily in South America, South Africa, Russia Sources of Minerals: E.A. Keller. 1992. Environmental Geology Extensive marine evaporite deposits in US – deposits left after water evaporates (large inland lake with no outlet) Major deposits of mercury in red, small deposits in green, bulk of productive deposits highlighted in blue = global occurrence mercury deposits along subduction zones, with volcanic systems Tectonic plate boundaries related to origin of ore deposits such as iron, gold, E.A. Keller. 1992. Environmental Geology copper, mercury US deposits of copper, beryllium, zinc, gold – not all deposits along tectonic boundaries E.A. Keller. 1992. Environmental Geology Global Metal Trade Suppliers Consumers – US, Japan, Europe Nonmetal Mineral Resources • Silicate minerals (gemstones, mica, talc, asbestos) Sand and gravel (for road and building construction) Salts Limestone (like sand, gravel mined and quarried for concrete, crushed for road rock) [greatest volume and dollar value of all nonmetal mineral resources] • Evaporites – halite (rock salt – deice roads in winter; table salt), gypsum (plaster board; wall covering Egyptians 5,000 yrs ago), potash (make fertilizers) • Sulfur deposits – mined mainly for sulfuric acid production (industry, car batteries, some medicinal products) • Graphite, feldspar, quartz crystals, diamonds – useful or demand for beauty • World industry dependent on 80 minerals / metals; 18 short supply (i.e. tin, platinum, gold, silver, lead) – 1/3 to ½ strategic metals & minerals U.S. Stock piles of strategic metals • Strategic metals and minerals - those a country uses but cannot produce itself • Wealthy industrial nations often stockpile strategic resources, especially metals E.A. Keller. 1992. Environmental Geology •Much of cycle connected to waste •Environmental impacts related to wastes •Not recycle – enormous economic burden & environmental impact •Metal recycling important difficult to find concentrated sources Percent of US consumption recycled: aluminum, copper, lead Al - more energy to extract from ore than recycle; is strategic metal E.A. Keller. 1992. Environmental Geology Pb – short supply, is strategic metal Part 4: Environmental Effects of Resource Extraction • Geologic resource extraction involves: 1) the physical processes of mining, 2) the physical or chemical processes of separating minerals, metals, and other geologic resources from ores or other materials. • Ore - a rock in which a valuable or useful metal occurs at a concentration high enough to make mining it economically attractive Mining and Air, Water Pollution • EPA lists > 100 toxic air pollutants released from US mines every year • Gold and other metals often found in sulfide ores found in hydrothermal deposits - sulfur-bearing minerals exposed to air produce highly mobile and strong acids - vast quantities of ores crushed and washed to extract metals, uses lots of water (Nevada 60 million gallons/day) that gets contaminated Mining • Placer mining • Strip-mining or open-pit mining – most common • Underground mining – tunneling deep • Tailings - surface waste deposits • Groundwater contamination • Spoil banks - acid and sediment runoff • Surface Mining Control and Reclamation Act (1977) • By 2000, cumulative land used for mining was less than 1 percent (0.2%) globally Hydraulic miners, 1910, in PNW Since CA gold rush of 1849, placer miners used water cannons to blast away hillsides Placer mining – ancient method of accumulating gold, diamonds, coal Bingham Canyon, Utah drainage into Blackfoot River 2.5 mi wide 2,640 feet deep Montana – HOW RECLAIM, RESTORE? No soil or biological legacy; Ground water in pits toxic (technology to detoxify not known Metals extracted from ores by heating (smelting) or chemical solvents – these more negative than mining Smelting – roasting ore to release metals using heat or chemical solvents Ducktown, Tennessee – most ecological devastating smelting operations created wastelands Heap-Leach Extraction – chemical extraction to dissolve pulverized ore (GOLD) Process for low-grade ores Uses cyanide trickling through crushed ore to extract gold, other precious metals Thick clay pad & plastic liner Kola peninsula – arctic border of Russia, Finland and Norway has biggest air polluting industries in Europe • Ni and Cu mines, rich in S • Around 1985, about 700 thousand tons of SO2/year • In 1994, about 350 thousand tons of SO2/yr (more than the total emissions of Norway, Sweden and Finland combined) Kola peninsula – all forests gone close to source, soil eroding, effects of nickel smelters extending from Russia into Finland and Norway, air pollution reaches critical limits Chemical legacy hard to restore back to natural High in: sulfur, copper, zinc, gold, iron 700 F Hydrothermal vents or ‘black smokers’ http://www.pbs.org/wnet/savageearth/hellscrust/html/sidebar2.html http://www.pmel.noaa.gov/vents/geology/MOR.html Ocean mining of rich mineral deposits a technological challenge Mid-ocean ridges E.A. Keller. 1992. Environmental Geology Geologic Hazards, Climate and Human Health Volcanic eruption in Indonesia in 1963 < air temperatures by 0.2 C for 2 years Natural volcanic eruptions result in similar Air Pollution and Human Health problems as mining causes Hekla eruption 1991 • Snow on North and Eastern Iceland pH 3 • Water close to Hekla was very toxic when it melted. • Gas movement from underground sources polluted groundwater (e.g.SO4). Lakagígar 1783-1784 eruptions Ash from eruption in Iceland fell in mainland Europe Gas aerosols released caused cooling in Northern Hemisphere (by 1 degree C). Lakagígar eruption 1780’s • More than 50 million tons of SO2 emitted (more than the current total annual emission of Europe) • Thick carpet of particulate and gaseous pollution over Iceland. • Pollution probably very acidic Lakagígar eruption – consequences in Iceland (1780s eruptions) • • • • Grass and other vegetation withered Birds fell dead from the sky Fish disappeared from the rivers Large part of livestock died due to eating fluorine contaminated grass (poisoned) • crop failure (by acid rain) • People experienced respiratory problems, death of 9,000 people (1/4 of residents of Iceland) due to famine Geology and Human Health Released during volcanic eruptions SO2 – sulfur dioxide HCl – hydrochloric acid HF – hydrogen fluoride [ aluminum smelters next biggest sources; very toxic to grazing animals] Asbestos Asbestos = ferromagnesium silicate, used brake lining & insulation, very heat resistant so prevents overheating of machinery & prevents fires LUNG DISEASE – can result in lung cancer Iodine deficiency in drinking water correlated to goiter frequency Lithium naturally in water in southwest results in less depressed Keller 1992people Environmental Geology Heart Disease and the Geochemical Environment Correlation between chemistry of drinking water (esp. hardness of water) and heart disease mortality Occurrence of heart attack death correlated to sulfate-rich and bicarbonate rich surface water, Ohio Cause-effect relationship: -soft water acidic & corrodes pipes releases trace elements into water that cause heart disease -hard water dissolves trace elements into water may prevent heart disease. Some trace elements in soil – manganese, chromium, vanadium, and copper, have been found to prevent heart disease