Encyclopedia of Global Resources part 9 pptx

in Industrial America. Cambridge, Mass.: Harvard University Press, 2008. Kalof, Linda, and Brigitte Resl, eds. A Cultural History of Animals. 6 vols. New York: Berg, 2007. Pynn, Larry. “Logging with Horse Power.” Canadian Geographic 111, no. 4 (August/September, 1991): 30. Schmidt, Michael J., and Richard Ross. “Working Ele- phants: They Earn Their Keep in Asia by Providing an EcologicallyBenignWay to HarvestForests.” Sci- entific American 274, no. 1 (January, 1996): 82. Tiwari, G. N., and M. K. Ghosal. “Draught Animal Power.” In Renewable Energy Resources: Basic Princi- ples and Applications. Harrow, England: Alpha Sci- ence International, 2005. Watts, Martin. Working Oxen. Princes Risborough, En- gland: Shire, 1999. See also: Animal breeding; Animal domestication; Livestock and animal husbandry; Transportation, energy use in. Animals as a medical resource Category: Plant and animal resources The use of animals has been a critical component of both human medical research and veterinary research. Although animal research has become a source of controversy among the public, nearly all modern medical advances have been based on some form of animal research. Background Animals have served purposes related to medicine for centuries. They provided medical products for apoth- ecaries in medieval Europe and for traditional Chi- nese medicine. Most applications, such as the use of ground rhinoceros horn as an aphrodisiac, were based on nonscientific concepts that have been dis- carded by modern medicine. However, some techniques, such as the use of spiderweb to stop bleeding, functioned until more effective products became available. More recently, insulin used to treat diabetes was first harvested from the pancreatic glands of cattle or pigs used in the meat industry; however, the foreign animal proteins sometimes caused allergic reactions. Today, genetically engineered bacteria can provide many hormone products that previously were ex- tracted from animals. Animals have also provided transplant organs. Tissue rejection has been a major problem, but medications can reduce rejection dra- matically. Through genetic engineering, genes that code for pharmaceutical proteins can be incorporated into animals, and medicinal drugs can then be produced from the animal’s milk. Clinical trials are under way for animal production of anti-blood-clotting agents. Transgenic animals have also been proposed for the production of drugs to treat cystic fibrosis, cancer, and other disorders. The uses of animals for products and tissues, however, have been minor compared with the useofanimalsas testsubjectsin medical research. Animal Medical Research Phenomenal advances in the treatment of human diseases occurred in the century following the Civil War. The development of germ theory by Louis Pasteur and Robert Koch, as well as the conquest of most major infectious diseases, was based on extensive animal research. Pasteur’s studies of chicken cholera formed a basis for his work, and Koch’s breakthrough work with anthrax involved studies with sheep. Most Nobel Prizes in Physiology or Medicine (first awarded in 1901) have involved some form of animal research. The first half of the twentieth century was an era of widespread public support for medical and scientific research. Animal research underlay basic studies in the development of penicillin and other major antibi- otics as well as insulin, surgical techniques, and vacci- nations. Partly because people had recent memories of the severity of such major diseases as smallpox and polio, animal research engendered little protest or controversy. Not all animals are equally useful or appropriate in medical research, because some have systems that dif- fer significantly from human physiology. The closer an animal is to humans evolutionarily, the more likely it is that it will respond to drugsandmedical interven- tions in the same manner that humans will. Most new drugs are first screened on laboratory rats or mice; those drugs that show promise and have no toxic ef- fects may then be tested on primates. Approximately 95 percent of medical research uses mice and other rodents, and nearly all the mice and rats used are “purpose bred” for research. (Cats, dogs, and nonhu - man primates make up less than 1 percent of animals 50 • Animals as a medical resource Global Resources used in research.) The protocols for Federal Drug Administration approval of new drugs, as well as agri- cultural and environmental standards, are based on substantial animal testing to ensure the safety and effectiveness of new medications. Opposition and Controversy Beginning in the late 1970’s, opposition to animal research began to gain national attention. The books Animal Liberation, byPeterSinger (1977), and The Case for Animal Rights, by Tom Regan (1983), provided a rationale to activists who questioned humans’ use of other animals for medical research as well as for food, fur, and educational uses. Organizations opposed to some or all animal use in research range from radical groups allegedly responsible for vandalism of research laboratories (the Animal Liberation Front is among the most radical groups) to milder animal protection- ist organizations. Probably the best-known animal- rights group is People for the Ethical Treatment of Animals (PETA). Well-known defenders of animal re - search for medical science include the National Asso- ciation for Biomedical Research (NABR), the Incurably Ill for Animal Research, and Putting People First. Some anti-animal-research activists have con- tended that all animal research can be replaced with alternatives such as research involving tissue culture and computer simulation. Activists also object to the use of animals taken from animal shelters and com- plain that current animal care regulations, particularly under the Animal Welfare Act, are not rigorously enforced by the U.S. Department of Agriculture. The scientific community has defended animal research for a number of reasons. Biological systems are much more complex than any computer model de- vised, so at present computer simulation has severe limitations. Newdrugs rarelyrespond intissueculture exactly as they do in a whole living organism. Re- searchers point out that, although animals are taken from shelters for research use, they constitute a mi- nuscule amount of the dogs and cats that are eutha- nized annually. By far, most of the animals used in research and teaching are mice and rats. Research facilities are inspected by agencies such as the United States Department of Agriculture’s Animal and Plant Health Inspection Service, which enforces Animal Welfare Act criteria. The Food and Drug Administra- tion and the Environmental Protection Agency also have laboratory practice regulations. The research community also states that approximately 95 percent of laboratory animals are never subjected to pain and that the remaining animals are provided pain- relieving drugs or anesthetics as soon as the study permits. John Richard Schrock Further Reading Birke, Lynda, Arnold Arluke, and Mike Michael. The Sacrifice: How Scientific Experiments Transform Ani- mals and People. West Lafayette, Ind.: Purdue Uni- versity Press, 2007. Carbone, Larry. What Animals Want: Expertise and Ad- vocacy in Laboratory Animal Welfare Policy. New York: Oxford University Press, 2004. Haugen, David M., ed. Animal Experimentation.De- troit: Greenhaven Press, 2007. Monamy, Vaughan. Animal Experimentation: A Guide to the Issues. 2d ed. New York: Cambridge University Press, 2009. Global Resources Animals as a medical resource • 51 This mouse was genetically engineered by researchers at the Univer - sity of California, Davis, to use in the study of breast cancer. (AP/ Wide World Photos) National Research Council of the National Acad - emies. Science, Medicine, and Animals: A Circle of Dis- covery. Washington, D.C.: National Research Coun- cil, National Academies Press, 2004. Paul, Ellen Frankel, and Jeffrey Paul, eds. Why Animal Experimentation Matters: The UseofAnimalsin Medical Research. Edison, N.J.: Transaction, 2001. Regan, Tom. The Case for Animal Rights. 1983. Reprint. Berkeley: University of California Press, 2004. Rudacille, Deborah. The Scalpel and the Butterfly: The Conflict Between Animal Research and Animal Protec- tion. Berkeley:Universityof California Press, 2001. Singer, Peter. Animal Liberation. 2d ed. New York: New York Review of Books, 1990. Verhetsel, Ernest. They Threaten Your Health: A Critique of the Antivivisection/Animal Rights Movement.Tuc- son, Ariz.: People for Ethical Animal Research, 1986. Web Sites Humane Society of the United States Animal Testing http://www.hsus.org/animals_in_research/ animal_testing National Academies Press Science, Medicine, and Animals http://www.nap.edu/ catalog.php?record_id=10733#toc U.S. Food and Drug Administration Animal Testing http://www.cfsan.fda.gov/~dms/cos-205.html See also: Animal breeding; Animal domestication; Biotechnology; Livestock and animal husbandry; Plants as a medical resource; Wildlife. Antarctic treaties Category: Laws and conventions Date: Final draft presented on December 1, 1959; became effective on June 23, 1961 The Antarctic Treaty of 1959, created and endorsed by representatives of the twelve signatory nations and endorsed by many other nations since, designates Antarc - tica as a demilitarized zone and bans commercial min - eral and oil exploration there until 2041, when the treaty’s provisions will be reviewed and possibly al - tered. It also bans the disposal of radioactive waste in the area. Background Exploration of Antarcticabeganearly in the twentieth century when sailors hunting whales and seals pene- trated the waters surrounding this forbidding continent. As early as 1940, seven countries—Argentina, Australia, Chile, France, New Zealand, Norway, and the United Kingdom—had laid claim to various parts of Antarctica. Some such claims overlapped, increasing the potential for conflict. Antarctica is unique among Earth’s seven continents because it has no permanent residents and no established government. Its harsh climate makes it more suitable for scientists than for soldiers and en- trepreneurs. During the International Geophysical Year (IGY), which ran from July 1, 1957, until Decem- ber 31, 1958, twelve nations built thirty-five scientific research stations on the continent and fifteen on the nearby Antarctic islands. As of 2009, there were sixty- five research stations in Antarctica, many of which op- erated only during the Antarctic summer, which runs from mid-October until early March. When the IGY ended, representatives from the twelve nations involved in that project gathered in Washington, D.C.,andproduced the AntarcticTreaty, whose sixteen articles spelled out how the continent would be devoted to scientific research. Representa- tives of the twelve signatory nations presented the treaty on December 1, 1959. It went into effect on June 23, 1961. Among other documents that compose the Antarc- tic Treaty System are the Conservation of Antarctic Fauna and Flora, the Convention for the Conserva- tion of Antarctic Seals, and the Convention on the Conservation of Antarctic Marine Living Resources. The Antarctic Treaty was expanded in 1991, when twenty-four countries signed the Madrid Protocol, which banned commercial development, mining, and exploration for oil on the continent for fifty years. This provision will be reconsidered in 2041. By 2010, forty-five nations,representing more than 80 percent of the world’s population, had endorsed the Antarctic treaties, which are the most effective such international treaties ever entered into by such a broad spectrum of nations. Antarctica remains the most peaceful of Earth’s seven continents, with repre - sentatives of nearly one hundred nations working co - 52 • Antarctic treaties Global Resources operatively on their scientific pursuits and sharing their findings with their fellow scientists. Provisions The provisions of the Antarctic treaties were not ac- cepted merely on the basis of a majority vote. They were, instead, passed by consensus, which explains, at least partially, their overwhelming success and broad acceptance. As the IGY neared its termination in 1958, considerable concern existed that the sevennationsthathad laid claim to parts of Antarctica would begin to have disputes about their claims. It was these concerns that led the U.S. State Department to inaugurate meetings in Washington, D.C., with eleven other nations that had vested interests in Antarctica. Representatives of these nations metformore than a year in an attempt to reach an accord that would protect Antarctica from widespread incursions from a host of nations. Through these meetings the Antarc- tic Treaty was forged. It was signed on December 1, 1959, by representatives of the twelve nations that par- ticipated in the IGY, after which it was ratified and went into effect on June 23, 1961. Perhaps the most important provision of the treaty is its stipulation that all of the signatories agree to abandon all territorial claims on this frozen continent. This provision alleviated the fear that the seven nations that had previously laid claim to parts of Ant- arctica, all of which were involved in drafting the treaty, would exercise what they considered their pro- prietary rights and could conceivably enter into dan- gerous conflicts to protect such rights. Once this caveat was overcome, the rest of the provisions of the treaty fell into place. Cognizant of the importance of keeping Antarctica a peaceful continent, the initial Antarctic Treaty banned all military activity on the continent. It also forbade the testing of weapons, nuclear testing, and the disposal of nuclear waste on the continent. These provisions set aside 10 percent of the Earth’s surface as nuclear-free and demilitarized zones. Among the protective stipulations of the Antarctic Treaty produced in 1959 is the prohibition of the im- portation of soil into the continent. The fear is that imported soil will carry with it unknown biohazards such as fungi, bacteria, and insects that might pollute the pristine atmosphere of Antarctica. Openness is a major theme of the treaty’s provi - sions, which call for the free exchange of scientific in - formation among the disparate groups of scientists who areinvolvedinpolar research. Scientistsfrom the signatory nations covered by the treaty are expected to share information with one another and to make their research plans and scientific outcomes available. The provisions of the treaty permit personnel from any of the research stations to visit and inspect without prior notice any of the research facilities in Antarctica. Realizing that disputes arise inevitably in multina- tional situations, those who drafted the treaty provided for conflict resolution. Efforts must be made to settle disputes through arbitration or negotiation. If such efforts fail, however, the problem is referred to the International CourtofJusticeforaresolution that is considered binding. Those who drafted the treaty were conscious of the needto make it sufficientlyflex- ible to dealwithnewissues or problems as theyarisein rapidly changing contexts. The official languages of the treaty are English, French, Russian, and Spanish. The documents associated with the treaty are held by the government of the United States, which is responsible for preserving them and distributing them as required. There are two levels of membership in the Antarc- tic Treaty System, consultative and nonconsultative. In order to be consultative members, nations must maintain at least one research station in Antarctica. Consultative members have voting rights that are not available to nonconsultative members. In some in- stances, consultative members close their research stations, as India did its Dakshin Gangotri Station in 1981, but as long as they maintain one station—India continues to maintain the Maitre Station as a permanent facility—they retain consultative membership. Since the enactment of the treaty, society has become increasingly sensitive to environmental problems that received less attention in the 1960’s than they did in the 1990’s and beyond. As a result of this change in outlook, the Madrid Protocol was enacted in 1991. It bans exploration for oil and other minerals in Antarctica for fifty years. In 2041, this provision will be revisited and possibly reconsidered. Impact on Resource Use Antarctica is a mineral-rich continent, but its harsh climate and the thick ice sheets—some more than 3 kilometers deep—that cover it make the retrieval of minerals expensive and hazardous. Many parts of the continent never reach temperatures above freezing, Global Resources Antarctic treaties • 53 and even those areas, such as the Antarctic Peninsula, that have more moderate climates are too cold to sus- tain much plant and animal life. Nevertheless, as mining equipment becomes increasingly sophisticated, the recoveryofoil and othermineralsfrom Antarctica will undoubtedly become feasible. The enactment of the Antarctic Treaty System has been aimed at the preservation of a frozen wilderness that has considerable potential as a source of natural resources, although this potential remains underde- veloped. Among the other natural resources of which the continent boasts are stores of fresh water, esti- mated to constitute 80 percent of the fresh water on Earth. As water shortages become commonplace in many parts of the developed world, means will be ex- plored for transporting some of Antarctica’s abun- dant water to water-starved regions. Some Middle Eastern countries have already ex- plored the possibilityofhaulinghugeicebergsinto areas that are parched and of using the fresh water in them for irrigation and other purposes, including drinking water. Most of the ice in icebergs is composed of fresh water. Future additions to the Antarc- tica Treaties will likely deal with the preservation and transportation of huge masses of ice into the popu- lated parts of the world that are much in need of water. At the same time, future amendments may need to address the consequences of global climate change as well. R. Baird Shuman Further Reading Bocknek, Jonathan. Antarctica: The Last Wilderness. North Mankato, Minn.:SmartApple Media, 2004. Currie, Stephen. Antarctica. New York: Lucent Books, 2004. Karner,Julie.RoaldAmundsen:The Conquest of the South Pole. New York: Crabtree, 2007. Myers, Walter Dean. Antarctica: Journeys to the South Pole. New York: Scholastic Press, 2004. Rubin, Jeff. Antarctica. 4th ed. London: Lonely Planet, 2008. Shackleton, Ernest. The Heart of the Antarctic: Being the Story of the British Antarctic Expedition, 1907-1909. New ed. London: Carroll and Graff, 1999. Stonehouse, Bernard. North Pole, South Pole: A Guide to the Ecology and Resources of the Arctic and Antarctic. London: Prion, 1990. See also: Climate and resources; Oil and natural gas distribution; Oil and natural gas exploration; Ozone layer and ozone hole debate; Population growth; Re- sources as a source of international conflict. Antimony Category: Mineral and other nonliving resources Where Found While antimony does not often occur free in nature, its ores are widely distributed. The antimony ore of greatest commercial importance is stibnite (Sb 2 S 3 ), most of which is supplied by China, Germany, Peru, and Japan, among other countries. Primary Uses Antimony is a strategic resource with many uses. It is a key component inmanyalloys, and its compounds are employed in the manufacture of such products as ceramics and glass, batteries, paints and pigments, chemicals, matches,explosives,fireworks, flame retardants, and medicines. Technical Definition Antimony (abbreviated Sb), atomic number 51, is a metalloid belonging to Group VA of the periodic table of the elements. It has two naturally occurring iso- topes and an average molecular weight of 121.75. Pure antimony has rhombohedral crystals and is silvery blue-white in color. It is brittle, can be easily powdered, and conducts heat and electricity poorly. Its specific gravity is 6.69 at 20° Celsius; its melting point is 630.5°Celsius,and its boilingpointis 1,380° Celsius. Description, Distribution, and Forms Antimony is a metalloid with a lithospheric concentration of 0.2 gram per metric ton. When used in met- allurgical combinations antimony forms hard, brittle materials that melt at relatively low temperatures, characteristics that make this element an important component in many alloys. The most economically important antimony ore is antimony sulfide, or stibnite. In the United States the element is usually obtained only as a by-product of smelting the copper ore tetrahedrite, (Cu, Fe) 12 Sb 4 S 13 , or other sulfide ores of base metals. While recycling scrap metal and storage batteries was once a signifi - cant secondary source of antimony for the United 54 • Antimony Global Resources States, the development of low-maintenance lead- acid automobile batteries that use lead alloys with less or no antimony has decreased this supply. In 2007, for example, the United States consumed 9,590 metric tons of antimony, and total world production was esti- mated at 170,000 metric tons. Antimony ores are widely distributed; China, Bo- livia, South Africa, Russia, Tajikistan, and Australia are the chief producers. China is believed to have the world’s greatest reserves of the element; extensive deposits of stibnite are found in the southern province of Hunan. Antimony-bearing rocks can be found in soils, groundwater, and surface waters. Most antimony deposits are associated with igneous activity and are believed to have been precipitated from watery fluids at relatively shallow depths and low temperatures. Antimony is rarely found free in nature. Stibnite, the predominant antimony ore, is a silvery gray sulfide mineral that occurs in masses or prismatic crystals. Frequently it is found in association with quartz and economic minerals such as ores of mercury, tungsten, tin, lead, copper, silver, andgold. Stibnite deposits are often in the form of veins, seams, pockets, or lenses. Antimony can enter groundwater and surface water through the natural weathering of rockorthrough industrial pollution. It can cause disorders of the human respiratory and cardiovascular systems, skin, and eyes, and it is a suspected cancer-causing agent. The 1974 Safe Drinking Water Act set the maximum allow- able concentration for total antimony in drinking water in the United States at 6 micrograms per liter. History Antimony has been used since biblical times as an in- gredient in medicines and in kohl, an eye cosmetic made up of powdered stibnite mixed with soot and other materials. In Tello, Chaldea, a vase from approximately 4000 b.c.e. was found that had been cast in elemental antimony; antimony was also reportedly used by the early Egyptians to coat copper items. By the sixteenth century, the element was recognized as an alloyingredient that couldimprove thetoneof bell metal; as a source of yellow pigment for painting earthenware, enamels, and glass; and as an ulcer medicine. The earliest known description of the extrac- tion of antimony from stibnite was written by Basilius Valentinus around 1600. The increasing industrializa- tion of the late nineteenth and early twentieth centu - ries was accompanied by a rapid rise in antimony consumption. The need for ammunition, arms, and flame-retardant items during World Wars I and II further increased the demand for antimony. In the 1930’s, consumption of the element also rose with the expansion of the automobile industry, which used lead-antimony alloys in storage batteries. Obtaining Antimony Antimony ore is roasted with iron in a blast furnace; the roasting produces antimony oxide, from which the iron removes the oxygen to free the antimony. A flux of sodium sulfate or sodium carbonate may be used to prevent the loss of molten antimony through evaporation. Complex ores, those with base metals present, are treated by leaching and electrolysis. Uses of Antimony Antimony is an important element in many alloys. Bri- tannia metal, an alloy of tin with antimony, copper, and sometimes bismuth andzinc,resembles pewterin appearance and is used in the manufacture of table- ware. Antimony is sometimes added to pewter, an alloy composed largely of tin, to increase whiteness and hardness. Babbitt metal, an antifriction alloy used in bearings, is composed chiefly of tin, copper, and anti - mony. Type metal, named for its use in the manufac - Global Resources Antimony • 55 Source: Mineral Commodity Summaries, 2009 Data from the U.S. Geological Survey, .U.S.GovernmentPrinting Office, 2009. Flame retardants 40% Transportation &batteries 22% Chemicals 14% Ceramics &glass 11% Other 13% U.S. End Uses of Antimony ture of printing type, is an alloy of lead with antimony, tin, and sometimes copper; this alloy is also used in metal parts for some musical instruments. Various alloys of antimony and lead are used in solder, starting- lighting-ignition batteries (particularly plates, termi- nals, and connectors), ammunition, communication equipment, corrosion-resistant pumps and pipes, tank linings, and roofing sheets. Antimony is used as a decolorizing and refining agent in television screens, fluorescent tubes, and op- tical glass. Small amounts of the element are used in some medicines. Antimony oxides serve as stabilizers and flame retardants in plastics. They are also used to make adhesives, rubber, textiles, paints, and other combustibles flame resistant. Antimony sulfides are employed as a component of fireworks and ammunition. Antimony compounds are used in the manufacture of matches, explosives, vulcanized rubber, paints and pigments, chemicals, semiconductors, batteries, glass, and ceramics. Its military applications make antimony a strategic mineral. Karen N. Kähler Further Reading Greenwood, N. N., and A. Earnshaw. “Arsenic, Anti- mony, and Bismuth.” In Chemistry of the Elements.2d ed. Boston: Butterworth-Heinemann, 1997. Henderson, William. “The Group 15(Pnictogen)Ele- ments: Nitrogen, Phosphorus, Arsenic, Antimony, and Bismuth.” In Main Group Chemistry. Cam- bridge, England:RoyalSociety of Chemistry, 2000. Krebs, Robert E. The History and Use of Our Earth’s Chemical Elements: A Reference Guide. Illustrations by Rae Déjur. 2d ed. Westport, Conn.: Greenwood Press, 2006. Massey, A. G. “Group 15: The Pnictides—Nitrogen, Phosphorus, Arsenic, Antimony, and Bismuth.” In Main GroupChemistry. 2ded.New York:Wiley, 2000. Web Sites Natural Resources Canada Canadian Minerals Yearbook, Mineral and Metal Commodity Reviews http://www.nrcan-rncan.gc.ca/mms-smm/busi- indu/cmy-amc/com-eng.htm U.S. Geological Survey Antimony: Statistics and Information http://minerals.usgs.gov/minerals/pubs/ commodity/antimony See also: Alloys; China; Germany; Hydrothermal solutions and mineralization; Japan; Metals and met- allurgy; Peru; Russia; South Africa; Strategic resources. Antiquities Act Categories: Laws and conventions; government and resources Date: Signed into law June 8, 1906 By designating sites of historic importance for special protection and preservation, the Act for the Preserva- tion of American Antiquities, commonly known as the Antiquities Act, pioneered the useofgovernment power to defend both the environmental and cultural resources of nations. Background As the population and economy of the United States expanded throughout the late nineteenth and early twentieth centuries, variousgroups becameconcerned about the survival of important elements of American culture and environment. Expanding urban centers threatened wilderness areas, unrestrained tourism damaged natural wonders, and archaeological sites were vulnerable to unregulated pillaging. The destruction of American Indian archaeological sites by commercial relic hunters was a particular concern, as archaeologists feared the loss or destruction of vital cultural artifacts. Their concerns reached the desk of Iowa congressman John F. Lacy, chairman of the House Committee on Public Lands (later the Committee on Natural Resources). Concerned about protecting properties in the public interest, Lacy in- troduced the Antiquities Act as a means of preserving properties of national importance even if the properties were in private hands. The act passed easily through Congress, and became law when signed by pro-conservation president Theodore Roosevelt. The Antiquities Act represented a move toward greater federal responsibility for preservation. Recog- nizing that state and local governments lacked either the will or the authority to protect sites of importance to the national heritage, the U.S. federal government used its power of eminent domain to placesites under government care. This marked a major philosophical shift away from government indifference to environ - 56 • Antiquities Act Global Resources mental issues and toward federal participation in preservation efforts. Provisions The Antiquities Act authorized the president of the United States to designate an area of historic, cultural, or environmental importance a “national monument” under the ownership and stewardship of the federal government, specifically the Department of the Interior. If thefederalgovernmentdidnot already own the property, the president could use the power of eminent domain to acquire private property. The act provided for the “proper care and management” of the site to ensure its preservation but did allow archaeological excavation by qualified researchers under the supervision of the government. In an attempt to curb the pillaging of artifacts, the unauthorized re- moval ofhistoricalartifactsbecame afederaloffense. Impact on Resource Use Although intended to protect archaeological sites, the Antiquities Act also ensured the survival of a number of environmentally important areas. President Roosevelt took a broad interpretation of the legisla- tion and designated a wide range of sites for protection. Roosevelt designated Devils Tower in Wyoming as the first national monument, followed by a number of American Indiansitesin the Southwest. Since 1906, the government has created more than one hundred monuments in both rural areas, such as Muir Woods in California, and urban areas, such as the Statue of Liberty in New York. Between 2006 and 2008, Presi- dent George W. Bush created the first underwater monuments when he designated the Papah3naumo- ku3kea Marine National Monument near Hawaii, Marianas Trench Marine in the central Pacific, and the Pacific Remote Islands and Rose Atoll Marines in the U.S owned islands of the South Pacific. Steven J. Ramold See also: National Park Service; National Parks Act, Canadian; National parks and nature reserves; Re- source Conservation and Recovery Act; Takings law and eminent domain. Appliances. See Buildings and appliances, energy-efficient Aquifers Category: Geological processes and formations An aquifer is a body of earth material that can store and transmit economically significant amounts of water. The earth material can be in either consolidated or unconsolidated form as long as it has sufficient permeability for the movement of water. In terms of groundwater occurrence, all the rocks found on and below the Earth’s surface are associated with either aquifers or confining beds. Background An aquifer is a rock unit that is permeable enough to yield water in usable amounts to a well or a spring. In geologic usage, the term “rock” includes unconsolidated sediments such as sand, silt, and clay, as well as what is commonly considered to be rock. A confining bed is a rock unit that has such low hydraulic conductivity (poor permeability) that it restricts or severely impedes theflowofgroundwater into oroutofnearby aquifers. Unconfined and Artesian Aquifers There aretwomajor types ofgroundwater occurrence in aquifers. The first type pertains to those aquifers that are only partially filled with water. In those cases, the upper surface (or water table) of the saturated zone can rise or decline in response to variations in precipitation, evaporation, and pumping from wells. The water in theseaquifersisclassifiedas unconfined, and such aquifers are called unconfined, or water- table, aquifers. The second type occurs whenwatercompletelyfills an aquifer that is overlain by a confining bed. In this case, the water in such an aquifer is classified as confined and the aquifers are called confined, or artesian, aquifers. In some fractured rock formations, such as thosethatoccurin the west-central portions of New Jersey and eastern Pennsylvania, local geologic conditions result in semiconfined aquifers that, as one might expect, have hydrogeologic characteristics of both unconfined and confined aquifers. Wells that are drilled in unconfined, water-table aquifers are simply called water-table wells. The water level in these unconfined wells indicates the depth be - low the surface of the water table, which is the top of the saturated zone. Wells that are drilled into con - Global Resources Aquifers • 57 fined aquifersare calledartesianwells. The water level in an artesian well is generally located at a height above the top of the confined aquifer but not neces- sarily above the land surface. Flowing artesian wells occur when the water level in an artesian well stands above thelandsurface. Thewaterlevel in tightly cased wells in unconfined or artesian aquifers is called the potentiometric surface of the aquifer. Aquifer Permeability Water flows (very slowly) in aquifers from recharge areas in interstream areas at higher elevations to dis- 58 • Aquifers Global Resources Source: Basic Ground-Water Hydrology Note: Ralph C. Heath, , U.S. Geological Survey Water-Supply Paper 2220, 1983. Rocks vary tremendously in their ability to conduct water. The meters-per-day scale is logarithmic: Each increment to the right and left of 1 indicates a change by a power of 10: to the right, 10 meters, 1,000 meters, and 100,000 meters; to the left, 0.1 meter, 0.01 meter, 0.001 meter, and so on. 10 –7 10 –6 10 –5 10 –4 10 –3 10 –2 10 –1 11010 2 10 3 10 4 10 –8 Meters per Day GRAVELGLACIAL TILL CLEAN SAND Fine Coarse SILTY SAND SILT, LOESS CLAY CARBONATE ROCKS Fractured Cavernous SHALE Unfractured Fractured SANDSTONE Fractured Semiconsolidated BASALT Unfractured Fractured Lava flow IGNEOUS AND METAMORPHIC ROCKS Unfractured Fractured 10 –7 10 –6 10 –5 10 –4 10 –3 10 –2 10 –1 11010 2 10 3 10 4 10 –8 Meters per Day Hydraulic Conductivity of Select Rocks and Materials charge areas along streams and adjacent floodplains at lower elevations. Thus, aquifers function as “pipe- lines” filled with various types of earth material. Darcy’s law governing groundwater flow was developed by Henry Darcy, a French engineer, in 1856. In brief, Darcy’s law states that the amount of water mov- ing through an aquifer per unit of time is dependent on the hydraulic conductivity (or permeability)ofthe aquifer, the cross-sectional area that is at a right angle to the direction of flow, and the hydraulic gradient. The hydraulic conductivity depends upon the size and interconnectedness of the pores and fractures in an aquifer. It ranges through an astonishing twelveor- ders of magnitude. There are few other physical pa- rameters that have such a wide range ofvalues. For example, the hydraulic conductivity ranges from an extremely low 10 −7 and 10 −8 meters per day in unfractured igneous rock such as diabase and basalt to as much as 10 3 and 10 4 meters per day in cavernous limestone and coarse gravel. Typical low-permeability earth materials include unfractured shale, clay, and glacial till. High-permeability earth materials include lava flows and coarse sand. In addition to this wide range of values, hydraulic conductivity varies widely in place and in direction- ality within the same aquifer. Aquifers are isotropic if the hydraulic conductivity is about the same in all directions, and anisotropic if it is different in different directions. Asaresult of all ofthesefactors, groundwater yield is extremely variable both within the same aquifer and from one aquifer to another when they are composed of different rocks. Aquifer Tests In order to determine the groundwater yield and contaminant transport characteristics of an aquifer, it is necessary to obtain sufficient geologic and hydrologic information. One of the most important hydrologic investigations insuchastudy is the analysis of the change over time of the water levels in an aquifer as a consequence of well pumpage. This type of study is called an aquifer test and usually involves pumping a well at a constant rate for several hours to several days while changes in the water levels of one or more observation wells located at different distances from the pumped well are measured. The test pro- vides invaluable information about the ability of an aquifer to yield sufficient water under the stress of constant pumping. Robert M. Hordon Further Reading Appelo, C. A. J., and D. Postma. Geochemistry, Ground- water, and Pollution. 2d ed. New York: Balkema, 2005. Fetter, C. W. Applied Hydrogeology. 4th ed. Upper Sad- dle River, N.J.: Prentice Hall, 2001. Price, Michael. Introducing Groundwater. 2d ed. New York: Chapman & Hall, 1996. Todd, David Keith, and Larry W. Mays. Groundwater Hydrology. 3d ed. Hoboken, N.J.: Wiley, 2005. Younger, Paul L. Groundwater in theEnvironment:AnIn- troduction. Malden, Mass.: Blackwell, 2007. Zektser, Igor S., and Lorne G. Everett, eds. Ground Water Resources of the World and Their Use. Paris: UNESCO, 2004. Reprint. Westerville, Ohio: Na- tional Ground Water Association Press, 2006. Web Sites Natural Resources Canada Groundwater http://atlas.nrcan.gc.ca/site/english/maps/ freshwater/distribution/groundwater/1 U.S. Geological Survey Aquifer Basics http://water.usgs.gov/ogw/aquiferbasics See also: Environmental engineering; Glaciation; Groundwater; Hydrology and the hydrologic cycle; Land-use planning; U.S. Geological Survey; Water pollution and water pollution control; Water supply systems. Argentina Categories: Countries; government and resources Argentina’s greatest primary natural resource isitsag- ricultural land. Owing to its size, Argentina has a variety of climates and soils in which to grow crops and raise livestock. As a result, the country is a top-ten exporter of a variety of crop and meat products. More- over, a complex geology endows Argentina with deposits of petroleum, natural gas, copper, gold, and other minerals that make the country a significant exporter of these materials to its neighbors and other countries around the globe. Global Resources Argentina • 59 . Planet, 2008. Shackleton, Ernest. The Heart of the Antarctic: Being the Story of the British Antarctic Expedition, 190 7- 190 9. New ed. London: Carroll and Graff, 199 9. Stonehouse, Bernard. North Pole,. conventions Date: Final draft presented on December 1, 195 9; became effective on June 23, 196 1 The Antarctic Treaty of 195 9, created and endorsed by representatives of the twelve signatory nations and endorsed. that received less attention in the 196 0’s than they did in the 199 0’s and beyond. As a result of this change in outlook, the Madrid Protocol was enacted in 199 1. It bans exploration for oil and

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