Review sheet for Exam 3 Chapter 9 Geology and mining Lithosphere and mantel Core solid iron in the center molten iron in the outer core Mantle less dense elastic rock Lithosphere harder rock that contains the mantle and crust the thin brittle low density layer of rock Smelting Surface mining Most minerals must be processed after mining After ore is mined rock is crushed and the metals are isolated by chemical or physical means the material is processed to purify the metal Alloy a metal is mixed melted or fused with another metal or nonmetal substance Smelting heating ore beyond its melting point then combining it with other metals or chemicals o Modifies the strength and malleability of metals Underground work accessing deep pockets of a mineral through tunnels and shafts up to 2 5 miles deep o Example of minerals that are surface mined Zinc lead nickel tin gold diamonds phosphate salt coal The most dangerous form of mining o Dynamite blasts collapsed tunnels o Toxic fumes and coal dust o Collapsed tunnels cause sinkholes Mountain removal Entire mountaintops are blasted off o Mine blasting cracks foundations and walls o Floods and rock slides affect properties o Coal dust and contaminated water cause illness o Lung cancer heart and kidney disease pulmonary disorders hypertension death Valley filling dumping rock and debris into valleys o For coal in the Appalachian Mountains of the eastern U S o Degrades and destroys vast areas pollutes streams deforests areas causes erosion mudslides flash floods and biodiversity loss The U S General Mining Act of 1872 Encourages metal and mineral mining on federal land Any citizen or company can stake a claim on or buy for 5 per acre any public land open to mining The public gets no payment for any minerals found Supporters say it encourages a domestic industry that is risky and requires investment to locate vital resources Critics say it gives valuable public land basically free to private interests Efforts to amend the act have failed in Congress Acid drainage Acid drainage sulfide in newly exposed rock reacts with oxygen and rainwater o Produces sulfuric acid which leaches toxic materials from rock o Flows into streams killing fish and other organisms o Pollutes groundwater used for drinking and irrigation Chapter 10 water crisis and air pollution Upwelling and downwelling Upwelling the rising of cold deep water to the surface o Rich in nutrients o High primary productivity and lucrative fisheries Downwelling the sinking of warm oxygen rich water o Provides oxygen for deep water life Pathogens and waterborne diseases Treatment of drinking water is widespread and successful in developed nations Before water reaches the user it is chemically treated then filtered and disinfected The EPA sets standards for over 90 drinking water contaminants o Local governments and private water suppliers must meet these standards Water treatment has reduced deaths from diseases it is one of the greatest advances of modern times Before the Clean Water Act untreated sewage was released into waterways which caused oxygen depletion and contamination Septic systems the most popular method of wastewater disposal in rural areas o Underground septic tanks separate solids and oils from water o The water drains into a field through perforated pipes o Microbes decompose pollutants in the water o Solid waste is periodically pumped out and landfilled Proportion of Freshwater use in industry household and agriculture Water supplies to agriculture 70 of our water use is for agriculture o Crop irrigation watering of livestock o 20 goes to industry 10 for residential use Consumptive use water is removed from an aquifer or surface water body and is not returned e g irrigation Nonconsumptive use does not remove or only temporarily removes water o Electricity generation at hydroelectric dams Why does agriculture use so much water o Rapid population growth requires more food and clothes o We use 70 more irrigation water than 50 years ago o Irrigation can double crop yields o 18 of land is irrigated but produces 40 of our crops o Irrigation is highly inefficient o Water evaporates in flood and furrow irrigation o 15 35 of irrigation water use is unsustainable o Water mining withdrawing water faster than it is replaced Impact of building dam and the Three Gorges Dam Dam any obstruction placed in a river or stream to block the flow of water o To prevent floods provide drinking water allow irrigation and generate electricity o 45 000 large dams in more than 140 nations o Only a few major rivers remain undammed In remote regions Canada Alaska Russia Africa China s Three Gorges Dam is the largest in the world o 385 mile long reservoir o 39 billion to build o Flooded 22 cities o Displaced 1 24 million o Submerged old sites o Drowned farmland and habitat eroded marshes and eroding tidal marshes Some dams are being removed o Some feel that the costs of dams outweigh their benefits o They are pushing to dismantle dams o Letting rivers flow free will Restore ecosystems reestablish economically valuable fisheries and revive river recreation fishing rafting Old dams or those that are no longer economical are candidates for removal 400 dams have been removed in the U S 500 more may be removed The Montreal Protocol chemicals Montreal Protocol 1987 196 nations agreed to cut CFC production in half by 1998 o Later agreements deepened cuts advanced timetables and addressed other ozone depleting o Industry shifted to safer alternative chemicals o We stopped the Antarctic ozone hole from getting worse o Challenges still face us o CFCs will remain in the stratosphere for decades o It can serve as a model for international environmental cooperation Industrial smog and Photochemical smog Smog an unhealthy mixture of air pollutants over urban areas Industrial smog burning coal or oil releases such as CO2 CO soot mercury and sulfur o Sulfuric acid is formed Regulations in developed countries reduced smog Coal burning industrializing countries faces health risks Due to lacked pollution control Photochemical brown fog Sunlight drives a chemical reactions between primary pollutants and atmospheric compounds forming ozone NO2 and many other compounds This appears as a brownish haze o Formed in hot sunny cities surrounded by mountains o Morning traffic releases NO and VOCs o Irritates eyes noses and throats Acid deposition and its consequence Acid deposition is another transboundary issue Acid deposition the