Encyclopedia of Global Resources part 70 pptx

beled and unlabeled analytes compete for limited amounts of a molecule that binds the analyte very specifically. RIA is used worldwide in the determina- tion of hormones, drugs, and viruses. The technique is so specific that con- centrations in the picomolar region can be measured. Another major use of radioisotopes is as tracers that de- termine metabolic pathways, transport processes, and reaction mechanisms. A compound labeled with a radioac- tive isotope is introduced into the pro- cess, and the radioactivity allows the compound to be followed through the mechanism. Pharmacokinetics is the study of the rates of move- ment and biotransformationofadrug and its metabo- lites in the body. Many kinetic parameters, such as a drug’s half-life in the body, can be determined by us- ing radiolabeled drugs and measuring radioactivity after some type of chromatographic separation of the parent drug from its metabolites. Radiopharmaceuticals are substances labeled with radionuclides that are used in the visualization of or- gans, the location of tumors, and the imaging of bio- chemical processes. This usage is based on the fact that a substance that is found in a healthy cell at a cer- tain concentration has a different concentration in damaged cells. The particular isotope used depends on the organ or biochemical process under study. Radioisotopes are used in many ways in industry. Gamma rays from cobalt 60 are used to examine ob- jects for cracks and other defects. Radioisotopes can be used to measure thickness of all types of rolled ma- terials and as tracers in locating leaks in pipes carry- ing liquids or gases. The fill level of closed containers is monitoredbyabsorptionorscatteringofradiation. In the chemical industry radioisotopes are used to indicate the completeness of a precipitation reaction. A radioisotope of the element to be precipitated is added to the solution to be precipitated. When the fil- trate is freeofradioactivity, precipitation is complete. Radioisotopes are used in dating ancient rocks and fossils. Carbon is used in dating fossils. All living or- ganisms are assumed to be in equilibrium with their environment, taking in carbon in food and expelling it throughrespirationandotherprocesses. A living or - ganism is assumed, when it dies, to have a certain per - centage of carbon 14, radioactive carbon. As the fossil ages the carbon 14 decays by beta emission, and its percentage is reduced. Since the decay rate is known, a reasonable age estimate can be obtained by measur- ing the rate of radioactive emission (proportional to percentage carbon 14) from the fossil. Uranium is used in a similar way to date rock samples that contain a mixture of uranium and lead, which is at the end of its decay chain. Grace A. Banks Further Reading Billington, D., G. G. Jayson, and P. J. Maltby. Radioiso- topes. Oxford, England: BIOS Scientific Publishers in association with the Biochemical Society, 1992. Choppin, Gregory R., Jan-Olov Liljenzin, and Jan Rydberg. Radiochemistry and Nuclear Chemistry.3d ed. Boston: Butterworth-Heinemann, 2002. Dragani6, Ivan G., Zorica D. Dragani6, and Jean-Pierre Adloff. Radiation and Radioactivity on Earth and Be- yond. 2d ed. Boca Raton, Fla.: CRC Press, 1993. Ehmann, William D., and Diane E. Vance. Radiochem- istry and Nuclear Methods of Analysis. New York: Wiley, 1991. Faure, Gunter, and Teresa M. Mensing. Isotopes: Princi- ples and Applications. 3d ed. Hoboken, N.J.: Wiley, 2005. Henriksen, Thormod. Radiation and Health. New York: Taylor & Francis, 2003. Serway, Raymond A., Chris Vuille, and Jerry S. Faughn. College Physics. 8th ed. Belmont, Calif.: Brooks/Cole Cengage Learning, 2009. Thornburn, C. C. Isotopes and Radiation in Biology. New York: Halstead Press Division, Wiley, 1972. Tykva, Richard, and Dieter Berg, eds. Man-Made and 638 • Isotopes, radioactive Global Resources Half-Lives of Some Unstable Isotopes Used in Dating Parent Isotope Daughter Product Half-Life Value Uranium 238 Lead 206 4.5 billion years Uranium 235 Lead 207 704 million years Thorium 232 Lead 208 14.0 billion years Rubidium 87 Strontium 87 48.8 billion years Potassium 40 Argon 40 1.25 billion years Samarium 147 Neodymium 143 106 billion years Source: U.S. Geological Survey. Natural Radioactivity in Environmental Pollution and Radiochronology. Boston: Kluwer Academic, 2004. Umland, Jean B., and Jon M. Bellama. General Chemistry. 3d ed. Belmont,Calif.:Thomson/BrooksCole,1999. Web Sites World Nuclear Association Radioisotopes in Industry http://www.world-nuclear.org/info/ default.aspx?id=548&terms=radioisotopes World Nuclear Association Radioisotopes in Medicine http://www.world-nuclear.org/info/ default.aspx?id=546&terms=radioisotopes See also: Atomic Energy Commission; Isotopes, sta- ble; Manhattan Project; Nuclear energy; Nuclear Reg- ulatory Commission; Plutonium; Radium; Thorium; Uranium. Isotopes, stable Category: Mineral and other nonliving resources Where Found Stable isotopes comprise the bulk of the material uni- verse. Some elements are found in only a single form, while others have several isotopes. For study and ap- plication, it is necessary to separate the various iso- topes from one another. A number of methods have been developed to accomplish isotope separation. Primary Uses Analysis of stable isotopes and isotopic composition is used extensively in a wide variety of fields. These in- clude soil and water analysis, plant tissue analysis, de- termination of metabolic pathways in plants and ani- mals (including humans), archaeology, forensics, the geosciences, and medicine. Technical Definition An isotope is one of two or more species of atom that have the same atomic number (number of protons) but different mass numbers (number of protons plus neutrons). Stable isotopes are those which are not ra - dioactive. Because the chemical properties of an ele - ment are almost exclusively determined by atomic number, different isotopes of the same element will exhibit nearly identical behavior in chemical reac- tions. Subtle differences in the physical properties of isotopes are attributable to their differing masses. Description, Distribution, and Forms There are approximately 260 stable isotopes. While most of the eighty-one stable elements that occur in nature consist of a mixture of two or more isotopes, twenty occur in only a single form. Among these are sodium, aluminum, phosphorus, and gold. At the other extreme, the element tin exhibits ten isotopic forms. Two elements with atomic numbers less than 84, technetium and promethium, have no stable iso- topes. The atomicweight of an element is the weighted average of its isotope masses as found in their natural distribution. For example, boron has two stable iso- topes: boron 10 (an isotope with mass number 10), which accounts for 20 percent of naturally occurring boron, and boron 11, which accounts for 80 percent. The atomic weight of boron is therefore (0.2) ×(10) + (0.8) × (11) = 10.8. In those elements that have natu- rally occurringisotopes,the relativeabundance of the various isotopes is found to be remarkably constant, independent of the source of the material. There are cases in which the abundances are found to vary, and these are of practical interest. History In the early part of the twentieth century, the discov- ery of radioactivity, radioactive elements, and the many distinctly different products of radioactive de- cays showed that there were far more atomic species than could be fit into the periodic table. Although possessing different physical properties, many of these species were chemically indistinguishable. In 1912, Joseph John Thomson, discoverer of the electron, found that when a beam of ionized neon gas was passed through a properly configured electro- magnetic field and allowed to fall on a photographic plate, two spots of unequal size were exposed. The size and location of the spots were those that would be ex- pected if the original neon consisted of two compo- nents—about 90 percent neon 20 and 10 percent neon 22. Later Francis William Aston improved the experimental apparatus so that each isotope was fo- cused to a point rather than smeared out. The device he developed, known as a mass spectrograph, allows much greater precision in the determination of iso - tope mass and abundance. Global Resources Isotopes, stable • 639 Obtaining Isotopes All methods for separating stable isotopes are based on mass difference or on some isotopic property that derives from it. The difficulty of isotope separation depends inversely upon the relative mass difference between the isotopes. For example, the two most abundant isotopes of hydrogen are ordinary hydrogen (hydrogen 1) and deuterium (hydrogen 2). These iso- topes have a relative mass difference of (2-1)/1 = 1, or 100 percent. The mass difference between chlorine 35 and chlorine 37, by contrast, is only (37-35)/35 = 0.057, or 5.7 percent. There are two types of separation methods. The only single-step method is electromagnetic separa- tion, which operates on the principle that the curva- ture of the path of a charged particle in a magnetic field is dependent on the particle mass. This is the same principle on which the mass spectrograph is based. Though it is a single-step technique, the amount of material that can be separated in this way is ex- tremely small. All other processes result in a separa- tion of the original material into two fractions, one slightly enriched in the heavier isotope. To obtain sig- nificant enrichment the process must be repeated a number of times by cascading identical stages. Such multistage methods include gaseous centrifugation, aerodynamic separation nozzles, fractional distilla- tion, thermal diffusion, gaseous diffusion, electroly- sis, and laser photochemicalseparation.For example, in centrifugation a vapor of the material to be sepa- rated flows downward in the outer part of a rotating cylinder and upward in the center. Because of the mass difference, the heavier isotope will be concen- trated in the outer region and can be removed to be enriched again in the next stage. Uses of Stable Isotopes Most stable isotope applications are based on two facts. First, isotopes of a given element behave nearly identically in chemical reactions. Second, the relative abundances of isotopes for a given element are nearly constant. The three principal types of applications are those in which deviations from the standard abun- dances are used to infer somethingaboutthe environ- ment and/or historyofthesample,those in which the isotopic ratio of a substance is altered so that the sub- stance may be traced through a system or process, and those in which small differences in the physical prop - erties of isotopes are used to understand process dy - namics. As an example of the first type of application, con - sider that the precise isotopic composition of water varies with place and time as it makes its way through the Earth’s complex hydrologic cycle. Knowledge of this variation allows for the study of storm behavior, identification of changes in global climatic patterns, and investigation of past climatic conditions through the study of water locked in glaciers, tree rings, and pack ice. The cycling of nitrogen in crop plants pro- vides an example of stable isotope tracer methods. Fertilizer tagged by enriching (or depleting) with ni- trogen-15 is applied to a crop planting. Subsequent analysis makes it possible to trace the quantities of fer- tilizer taken up by the plants, remaining in the soil, lost to the atmosphere by denitrification, and leached into runoff water. Michael K. Rulison Further Reading Asimov, Isaac. The History of Physics. New York: Walker, 1984. Bransden, B. H., and C. J. Joachain. Physics of Atoms and Molecules. 2ded.NewYork: Prentice Hall, 2003. Clayton, Donald D. Handbook of Isotopes in the Cosmos: Hydrogen to Gallium. New York: Cambridge Univer- sity Press, 2003. Ehleringer, James R., and Thure E. Cerling. “Stable Isotopes.” In The Earth System: Biological and Ecologi- cal Dimensions of Global Environmental Change,ed- ited by Harold A. Mooney and Joseph G. Canadell. Vol. 2 in Encyclopedia of Global Environmental Change. New York: Wiley, 2002. Fry, Brian. Stable Isotope Ecology. New York: Springer, 2006. Hobson, Keith A., and Leonard I. Wassenaar, eds. Tracking Animal Migration with Stable Isotopes.Am- sterdam: Academic Press, 2008. National Research Council. Separated Isotopes: Vital Tools for Science and Medicine. Washington, D.C.: National Academy Press, available from Office of Chemistry and Chemical Technology, National Re- search Council, 1982. Web Site Northern Arizona University, Colorado Plateau Stable Isotope Laboratory What Are Stable Isotopes? http://www.mpcer.nau.edu/isotopelab/ isotope.html 640 • Isotopes, stable Global Resources See also: Biotechnology; Hydrology and the hydro - logic cycle; Isotopes, radioactive; Nitrogen cycle; Nu- clear energy; Soil testing and analysis. Italy Categories: Countries; government and resources Italy is one of the world’s leading producers of wine, ol- ive oil, and cheese. Olive trees and vineyards can be found throughout the country. The town of Carrara is world famous for the quality of its marble deposits. The Country A founding member of the European Union, Italy be- came a nation-state in 1861 and a republic in 1946. It- aly is a peninsula that extendsinto the Mediterranean Sea in southern Europe. The country comprises a boot-shaped mainland, the islands of Sicily and Sar- dinia, and several smaller islands. Italy shares borders with Austria, Switzerland, France, San Marino, and Slovenia. Natural threats to the nation include earth- quakes, volcanic eruptions,mudslides,andavalanches, along with land subsidence in Venice. Three-quarters of the country is mountainous; the Alps stretch across the northern region, and the Apennines run south- ward along the peninsula. The southern area of the country has four active volcanoes, including Mount Vesuvius and Mount Etna. In 2008, Italy’s economy was the fourth largest in Europe and seventh world- wide. The country is known for its cuisine, wine, cheese, olive oil, and marble. Italy has played a large role in European and global history. Home to Etrus- cans and later the Romans, Italy has been influential in the fields of architecture, literature, painting, sculp- ture, science, education, government, philosophy, mu- sic, and fashion. Olive Oil Italy is one of the top-two leading producers of olive oil in the world. Fossils of olive trees have been found in Italy dating back 20 million years. The culture of producing olive oil, however, did not emerge in the area until much later. The spread of theGreek empire brought olives to southern Italy in the eighth century b.c.e. The Romans planted olive trees throughout the Mediterranean region. Ancient historians wrote about Italian olive oil as being reasonably priced and the best in the Mediterranean. Olive oil was a main ingredient in various ointments and was believed to increase strength and youthfulness. Leading produc- ers of extra virgin olive oil are the regions of Liguria, Tuscany, Umbria, and Apulia. One-third of Italy’s olive oil trees are in the Apulia region. The taste and quality of the oil is affected by the type of olives, climate and conditions where they are grown, the method of harvest, and the production process. The Italian government strictly controls the extra virgin olive oil industry; in order to earn the distinc- tion of extra virgin the oil must have an acidity level of less than 1 percent. In 1998, the United States im- ported 131 million liters of olive oil from Italy. Olive oil from Italy is among the highest priced and most in demand. This has led companies to mix lower quality oil with Italian oil in order to produce a cheaper prod- uct. The oil is then labeled as being imported from It- aly. In March, 2008, the Italian government arrested twenty-three people and shut down eighty-five farms involved in schemes to sell counterfeit Italian olive oil. The following month, the government arrested forty people who were adding chlorophyll to sun- flower and soybean oils. The oil was then sold through- outItaly and around the world as extra virgin olive oil. Twenty-five thousand liters of the counterfeit oil were confiscated before it could be exported. Marble Carrara, located in the Apuan Alps in northwestern Tuscany, isthe marble capital of Italy. It produces one- third of all the marble quarried in Italy. The area was first mined by the Romans, who used slaves and con- victs to extract the rock. They would insert damp wooden wedges into existing cracking in the rock face; the wood would then expand, loosening the marble. In 1570, gunpowder was first used in Carrara to extract marble from the mountainside. Explosives drastically changed the landscape of the area as more quarriesopenedandlargerchunksofmarblewereex- tracted. A hydroelectric plant was built nearby in 1910, which allowed the quarries to use electricity for the first time. This technology is used in the nearly three hundred active marble quarries in Carrara. Several varieties of marble are mined in the area, including the uncommonly white, flawless marble for which the town is famous. The port of Marina di Car- rara is one of the most famous in Italy and is known worldwide for loading and unloading marble and granite. During the early sixteenth century, sculptor Global Resources Italy • 641 642 • Italy Global Resources Italy: Resources at a Glance Official name: Italian Republic Government: Republic Capital city: Rome Area: 116,314 mi 2 ; 301,340 km 2 Population (2009 est.): 58,126,212 Language: Italian Monetary unit: euro (EUR) Economic summary: GDP composition by sector (2008 est.): agriculture, 2%; industry, 27%; services, 71% Natural resources: coal, mercury, zinc, potash, marble, barite, asbestos, pumice, fluorspar, feldspar, pyrite (sulfur), natural gas and crude oil reserves, fish, arable land Land use (2005): arable land, 26.41%; permanent crops, 9.09%; other, 64.5% Industries: tourism, machinery, iron and steel, chemicals, food processing, textiles, motor vehicles, clothing, footwear, ceramics Agricultural products: fruits, vegetables, grapes, potatoes, sugar beets, soybeans, grain, olives, beef, dairy products, fish Exports (2008 est.): $546.9 billion Commodities exported: engineering products, textiles and clothing, production machinery, motor vehicles, transport equipment, chemicals, food, beverages and tobacco, minerals and nonferrous metals Imports (2008 est.): $546.9 billion Commodities imported: engineering products, chemicals, transport equipment, energy products, minerals and nonferrous metals, textiles and clothing, food, beverages, and tobacco Labor force (2008 est.): 25.11 million Labor force by occupation (2005): agriculture, 4.2%; industry, 30.7%; services, 65.1% Energy resources: Electricity production (2007 est.): 292.1 billion kWh Electricity consumption (2006 est.): 316.3 billion kWh Electricity exports (2007 est.): 1.916 billion kWh Electricity imports (2007 est.): 34.56 billion kWh Natural gas production (2007 est.): 9.706 billion m 3 Natural gas consumption (2007 est.): 84.89 billion m 3 Natural gas exports (2007 est.): 68 million m 3 Natural gas imports (2007 est.): 73.95 billion m 3 Natural gas proved reserves ( Jan. 2008 est.): 94.15 billion m 3 Oil production (2007 est.): 166,600 bbl/day Oil imports (2005): 2.223 million bbl/day Oil proved reserves ( Jan. 2008 est.): 406.5 million bbl Source: Data from The World Factbook 2009. Washington, D.C.: Central Intelligence Agency, 2009. Notes: Data are the most recent tracked by the CIA. Values are given in U.S. dollars. Abbreviations: bbl/day = barrels per day; GDP = gross domestic product; km 2 = square kilometers; kWh = kilowatt-hours; m 3 = cubic meters; mi 2 = square miles. Rome Italy Austria France Hungary Greece Albania Yugoslavia Bosnia Croatia Slovenia Switzerland Algeria Tunisia Adriatic Sea Ionian Sea Mediterranean Sea Tyrrhenian Sea Michelangelo (1475-1564) traveled often to the quar - ries to pick out marble for his projects, including Da- vid. Carrara marble was used to build the Pantheon, Trajan’s Column in Rome, the Marble Arch in Lon- don, and the Cathedral of Siena. The stone is also used as a facade for buildings worldwide. Carrara is home to many fairs that celebrate marble and quarrying. In 1982, the town opened the Marble Museum of Carrara to preserve the history of marble and the marble indus- try in the area. The museum has several sections, in- cluding archaeological relics, drawings, photographs, plaster casts, sculptures, and industrialartwork. It also tells the history of marble quarrying and has machin- ery, technical diagrams, and photographs. The gal- lery contains more than three hundred samples of marble, granite, and rock from Italy and elsewhere. Feldspar Feldspar is a group of minerals that compose up to 60 percent of the Earth’s crust. The mineral can be found as crystals in granite or other igneous rock, in sedimentary rocks, in metamorphic rocks, or in veins. Feldspars are often pink, white, gray, or brown. The color varies with the chemical composition of the mineral. Feldspars are used in glassmaking, tile, ce- ramics, abrasive cleaners, and many other products. Italy was the leading feldspar producer throughout the 1990’s, vastly outmining the rest of the world. By 1998, Italy was producing almost 2.1 million metric tons of feldspar. At that time, Italy’s tile industry was among the top in the world, and the ceramics indus- try was among the leaders in Europe. The Maffei Sarda company began mining feldspar in northern Sardinia in 1989. In the late 1990’s, the company began producing a soda-potash feldspar that is unusually white in color and has been used to make bone china. At the time, another mining company de- veloped a process to extractfeldsparfrom granite that it recovered from a mining dump in Italy’s Lake Maggiore region. Italy’s yearly production of feldspar continues to increase; in 2008, the country mined 4.2 million metric tons. In 2008, Italy continued to be the top producer of feldspar, followed by Turkey, China, and Thailand. That year, Italian feldspar accounted for almost one-quarter of the total worldproduction. Metal and Mineral Resources Italy mines a variety of metals, including copper, lead, zinc, gold, and mercury. The majority of mining com - panies and mines are government controlled. Some privatization of the industry began during the 1990’s. During the 1970’s, Italy was a leading producer of py- rites, fluorite, salt, and asbestos. The country also mined enough zinc, sulfur, lead, and aluminum to meet its own demand. However, less than two decades later, Italy had drastically depleted these resources and was no longer self-sufficient. One-half of the country’s iron production is from Elba Island. The last iron cave was closed there in 1981. The island is also home to the Mining Museum. The museum has more than one thousand rocks and minerals on display and allows visitors to tour a mine. The majority of Italy’s metals are found on its islands; the decline of mining and depletion of the deposits have severely impacted their economies. The world’s second largest mercury mine is lo- cated in Idrija, Slovenia. The region has been con- trolled by a number of different European nations; it was controlled by Italy between World Wars I and II. The Idrija mine was in operation by the time Christo- pher Columbus set sail for the West Indies in 1492. Mercury was first exported through Venice, followed by Amsterdam in 1659. After more than five hundred years in operation, theminewas shut down because of declining mercuryore prices. Mercuryis still found in the Lake Maggiore region of Italy. Coal The island of Sardinia has a long history of coal min- ing. During the fascist period, a large number of the island’s swamplands were drained to produce farm- able land. Several agrarian communities began to form in these areas. At this time, the city of Carbonia was also established, which became the mining center of Sardinia. Tourism increased on the island by the early 1950’s, which led to a decrease in coal mining. By 2007, the Miniera Monte Sinni mine, located in the Sulcis basin in southwestern Sardinia, was the only ac- tive underground coal mine in Italy. It produced on average only 90,000 metric tons of coal each year. Italy, however, has largecoal reserves: an estimated544mil- lion metric tons, of which 30.8 million metric tons are minable, according to a 2007 study. A 2003 estimate placed the country’s reserves at more than 900 mil- lion metric tons. The study also estimated that the Sulcis basin had produced 72.6 million metric tons of coal. Production of lignite from Italy’s only lignite mine declined drastically between 1998(141,500 met - ric tons) and 2002 (9,000 metric tons). The Tuscan mine was shut down in 2003. Global Resources Italy • 643 Italy was fourth among energy consumption in Eu - ropean countries. This growing demand for power sources has increased Italy’sdependenceoncoal.The use of coal has met some political opposition but is aided by advances in the “clean coal” industry. In 2008, Italy’s largest power company, Enel, converteda large power plant from oil tocoal.The plant is located northwest of Rome, in Civitavecchia. The company defends this move as a means to lower costs; fuel costs have risen 151 percent since 1996. Italy has the high- est electricity prices in Europe. The country plans to produce 33 percent of its power from coal, more than double the 14 percent it produced prior to 2008. Wine The Etruscans, who were located in what is now north- ern Italy, and the Greek colonists to the south began Italy’slong history withwinemaking.After taking con- trol of the area, the Romans started their own vine- yards. Winemaking in the Roman Empire was a large enterprise and pioneered mass production storage methods like barrel making and bottling. The Ro- mans operated several vineyard plantations manned with slave labor on much of the coastal area of the re- gion. The plantations were so extensive that in 92 c.e. the emperor had to shut down a number of them in order to use the land for food production. Today, Italy is one of the two leading wine produc- ers in the world. In 2005, Italian wine accounted for 20 percent of the world’s wine. The United States im- ported nearly one-third of the total from Italy (36 per- cent by dollar value). Italy produces wines of many flavors, colors, and styles. There are approximately one million vineyards throughout modern Italy. The country has twenty wine regions, which are also its po- litical districts. The economy of the Apulia region is based primarily on wine, with 106,712 hectares of grapes and a yearly output of approximately 723.7 million liters of wine. The islands of Sardinia and Sic- ily are also major wine producers. Tuscany is famous for its red wines. About 70 percent of the 216 million liters produced there each year are red wines. The re- gion has more than 63,537 hectares of vineyards. Starting in 1968, winemakers began producing “super Tuscans,” wines that are not mixed according to the traditional blending laws of the area. During the 1970’s, Tignanello became one of the first super Tus- cans by eliminating the white grapes from a recipe for chianti. Piero Antinori replaced them with red Bor - deaux grapes in order to produce a richer wine. The new wines do not fit into any of the four traditional categories in which Italian wine is classified. However, winemakers throughout the country continue to ex- periment and create new wines. Fish Even though the majority of fish and seafood con- sumed in Italy is imported, fish production in the country has risen since the 1960’s. During the mid- 1980’stheEuropean Union passed the Common Fish- eries Policy. The policy is designed to eliminate over- fishing and maintain a competitive fish and seafood industry within Europe. In 2002, a European Union commission reduced the catch limits on the number of cod and other species of fish that had dwindling numbers. In 2004, subsidies for fisherman to help procure new vessels were eliminated. Because of this, the number of Italian fishing ships has decreased, leaving mostly small-scale fishing operations. In 2003, Italian fishermen caught 26 percent less fish than the previous year. The northern region of Italy houses 62 percent of the country’s fish farms; 22 percent are found in central Italy, and 16 percent in the southern region. These fisheries produced $405 million worth of fish in 2003. Canada is a large importer of fish to It- aly, but retailers face atough obstacle: Italian consum- ers are used to purchasing fresh goods, not canned or frozen. These companies may be added by the grow- ing demand for value and the convenience of ready- made food. Other Resources In addition to olives and grapes, Italy is famous world- wide for its cheeses. The country produces more than four hundred different varieties of cheese. In 2008, the government purchased 200,000 wheels of cheese (29.9 kilograms each) to help feed the poor, as food lines and the number of needy grew in the major cit- ies. Italy is also a major exporter of rice and tomatoes. During the late twentieth century, tomato farms dou- bled in size,andproductionquadrupled. Northern It- aly grows three times the amount of wheat as the southern regions, which is used to make pizza crusts and pasta. The country consumes a large portion of the agricultural products that it produces. Eighty per- cent of Italy’s citrus fruit is grown in Sicily. Italy is also a leading producer of apples, oranges, lemons, pears, and other fruits as well as flowers and vegetables. Potash can be various chemical compounds, mostly potassium carbonate. Potassium oxide potash is used 644 • Italy Global Resources in fertilizer. The town of Agrigento in southern Sicily has an economy that is largely based on potash and sulfur mining. The nearby harbor is Italy’s principal sulfur port. Jennifer L. Campbell Further Reading Clark, Martin. Modern Italy: 1871 to the Present. New York: Pearson Longman, 2008. Davis, John Anthony. Italy in the Nineteenth Century, 1796-1900. New York: Oxford University Press, 2001. Duggan, Christopher. A Concise History of Italy.Up- dated ed. New York: Cambridge University Press, 2006. Knickerbocker, Peggy. Olive Oil: From Tree to Table. San Francisco: Chronicle Books, 2007. Leivick, Joel. Carrara: The Marble Quarries of Tuscany. Palo Alto, Calif.: Stanford University Press, 1999. Lintner, Valerio. A Traveler’s History of Italy. 8th ed. Northampton, Mass.: Interlink, 2008. Romaneili, Leonardo. Olive Oil: An Italian Pantry. San Francisco: Wine Appreciation Guild, 2003. Scigliano, Eric. Michelangelo’s Mountain: The Quest for Perfection in the Marble Quarries of Carrara. New York: Free Press, 2005. See also: Agricultural products; Agriculture indus- try; Coal; Feldspars; Fisheries; Marble; Potash; Wheat. Ivory Category: Plant and animal resources Where Found Ivory is obtained from the large teeth and tusks of sev- eral mammals, including the elephant, hippopota- mus, walrus, extinct wooly mammoth, and narwhal. In these animals, an upper incisor grows throughout life into a largetusk. In elephants, for example,the av- erage tusk weighs 7 kilograms, but in large males the weight might be much more. A major factor endan- gering the continued existence of these extant mam- mals has been the value of their ivory. Primary Uses Ivory hasbeenusedbyhumansforthousands of years, often as a medium for carving. The art of scrimshaw makes use of ivory, and many other ornamental ob - jects are carved from ivory. In the past, most ivory was used in the manufacture of piano keys, but billiard balls, bagpipes, flatware handles, and furniture inlays were other products made from ivory. Today, most ivory is used for the Chinese, Japanese, and Korean seals known as hankos; these small seals are used on of- ficial business documents. Technical Definition Ivory isthehardened dentine of the teeth and tusksof certain large mammals. In both male and female ele- phants, one incisor on each side of the upper jaw grows throughout life. In females, growth of the tusks tends to slow after age thirty, but in males both the length and bulk of the tusks increase through the life span, thus making old male elephants prime targets for ivory poachers. In walruses, the tusks form from upper canines and grow throughoutlifeinbothsexes. Narwhals have only two teeth, both in the upper jaw; these lengthen to become long, straight tusks, usually only one in males and sometimes two in females. Hip- popotamuses have tusks of ivory that do not yellow with age, as elephant tusks tend to do. Description, Distribution, and Forms Both the Asiatic elephant, Elephas maximus, and the African elephant, Loxodonta africana, have been ex- tensively exploited for the ivory in their tusks. Asiatic elephants are now restricted in range to southern Asia, although historically they had a much larger dis- tribution, from Syria to northern China and south to Sri Lanka, Sumatra, and perhaps Java. According to 2008 population estimates, only 34,000 to 54,000 wild Asiatic elephants remain throughout the present range of the species. Approximately 17,000 to 23,000 are found on the Indian subcontinent, 11,000 to 20,000 in continental Southeast Asia, and 6,000 to 11,000 in Sri Lanka, Sumatra, and Borneo. The African elephant includes two major kinds, which some experts consider subspecies: the forest elephant, Loxodonta africana cyclotis, of west and cen- tral Africa, and the savanna or bush elephant, Loxo- donta africana africana, of the savanna areas of sub- Saharan Africa. Intense pressure from both legal and illegal ivory hunters caused the entire African ele- phant population to fall from around 1.3 million in 1979 to 625,000 in 1989. More recent estimates place the population throughout Africa to be no more than 500,000. In 1990, the United Nations Convention on Global Resources Ivory • 645 Trade in Endangered Species of Wild Fauna and Flora (CITES) put a ban on the international trade of ivory, and this slowed to some extent the killing of ele- phants. A now-extinct relative of the elephant, the woolly mammoth, Mammuthus primigenius, once ranged throughout the cold, northern areas of Asia and por- tions of North America. Globalclimatechangehas ex- posed the bodies of many mammoths and their tusks have been gathered, mostly by Russian workers, as a source of ivory. The walrus, Odobenus rosmarus, occurs in coastal ar- eas of the Arctic Ocean and adjoining seas. This spe- cies has been heavily exploited for the ivory of its large upper canines, which may be more than 100 centime- ters long in males and about 80 centimeters in fe- males. Biologists are concerned that with the decline of the African elephant population as a source of ivory, poachers will turn to the killing of walruses. Narwhals, Monodon monoceros, are found in the Arc- tic Ocean and nearby seas, primarily between 70° and 80° north latitude. Their normal range is entirely above the Arctic Circle. Narwhals have two upper-jaw teeth; in males, one of these remains embedded while the other erupts and grows in a spiral pattern to form a long, straight tusk. This tusk may be about one-third to one-half of the animal’s total body length, some- times becoming as long as 300 centimeters with a weight of 10 kilograms. Occasionally, one or two tusks are grown by a female narwhal. Most researchers be- lieve that the narwhal uses the tusk as a defensive weapon, because extensive scarring is often found on the heads of males. The hippopotamus, Hippopotamus amphibius,oc- curs throughout Africa in suitable waterways south of the Sahara Desert and also in the Nile River to its delta. It has disappeared throughout most of western and southern Africa,partiallybecauseitiskilledforits ivory tusks. Some of the lower canine tusks of male hippos are just as large as many elephant tusks enter- ing the ivory market, causing the hippo to be a target for illegal trafficking in ivory. History The trade in ivory is thought to date to the time of Cro-Magnon man, approximatelythirty-five thousand years ago. The Asiatic elephant has been ex- ploited for ivory for at least four thousand years; upper classes in both Asia and the Mid- dle East greatly desired items made of ivory. Ivory demand in Europe in the 1600’s drove the killing of many thousands of elephants around the Cape of Good Hope. From 1860 to 1930, 25,000 to 100,000 elephants were killed each year for the ivory trade, mostly to obtain material for piano key manufacture. By the early nineteenth century, the ivory-carving in- dustry in India was being supported by im- ported African elephanttusks,as the Asiatic el- ephants had already been seriously depleted. The overall number of elephants in Africa in the early 1900’s was still several million and re- mained so until after World War II. The mid-twentieth century had a lag in commercial ivory hunting, but in the 1970’s hunting resumed in earnest as the raw ivory price increased from five to one hundred dol- lars per kilogram. The African elephant was placed on appendix 2 of CITES in 1979, listed as vulnerable by the International Union for Conservation of Nature, and listed as threat - ened by the United States Department of the Interior. However, these listings did little to 646 • Ivory Global Resources This Asian elephant displays tusks of ivory that are 2.5 meters long. The il - licit ivory trade is an endangerment to elephants. (©iStockphoto.com) prevent poaching, and the African elephant popula - tion plummeted to 600,000 by 1997. In 1990, CITES banned the international trade of ivory, but in 1997, the convention approved the sale of more than 54 metric tons of ivory from Botswana, Namibia, and Zimbabwe. This stockpiled ivory was sold to Japan. CITES reinstated a trade ban againin2000, then once more allowed an exception in 2002 for Botswana, Na- mibia, and South Africa. In 2004, Namibia’s proposal to allow tourist trade in ivory carvings was approved; many conservationists believe that CITES’ imposing and then temporarily lifting ivory bans has encour- aged poaching in the African countries where larger populations of elephants still exist. In 2007, in re- sponse to public pressure on the ivory trade issue, eBay banned all international sales of elephant ivory products and in 2009 disallowed any sales of ivory by users of its Web site. China’s growing economy has driven illegal trade in ivory as well as attracted organized crime related to its sale. A kilogram of ivory brings about $750. Esti- mated illegal shipments to China total approximately 218 metric tons, an amount that would cause the deaths of at least 23,000 elephants. One tool available to conservation law enforce- ment is DNA testing. A genetic test developed by Sam- uel Wasser of the University of Washington helps to track illegal shipments to their source. For example, an extremely large illegal shipment of 532 tusks and 42,000 hankos was seized in Singapore in 2002. Ge- netic testing traced this ivory to Zambia, and the tusks in the shipment weighed approximately 11 kilograms each, indicating that they came from old elephants. Obtaining Ivory Generally, ivory is obtained by the killing of the ani- mals that possess ivory teeth and tusks. As mentioned above, these include elephants, hippopotamuses, nar- whals, and walruses. Mammoth ivory is obtained primarily in Russia by those who find recently thawed mammoth carcasses. Because of global climate change, this has become a more common occurrence. Mammoth ivory has been used by Russian merchants in the manufacture of items to sell to Asia. About 90 percent of mammoth ivory exported to Asia is used to make hankos for Chi- nese, Japanese, and Korean markets. This ivory, be- cause it comes fromanextinctmammal,canbelegally imported into the United States. More than 46 metric tons were imported in 2007. Dealers in Moscow re - port that they can sell mammoth ivory for three hun - dred to four hundred dollars per kilogram in Russia; in western markets it sells for up to sixteen hundred dollars per kilogram. Native subsistence hunting of walruses, by har- pooning or clubbing, has been occurring for thou- sands of years and probably had little negative impact on populations of the species. However, with the hunting of walrusesbyEuropeansforivory, hides, and oil, beginning in the sixteenth century, numbers of the animals on both sides of the North Atlantic de- clined dramatically. The last large populations in the Canadian Arctic were gone by the 1930’s, and only about 25,000 of the Atlantic population remain. Re- cent surveys of the Pacific population indicate that some 200,000 walruses are present, but there is con- siderable concern among biologists that ivory de- mand in Asia will drive poaching of theremaining ani- mals. Hippopotamuses have been extensively killed for hundreds of years for meat, hides, and ivory. As popu- lations of African elephants have steadily declined, there has been increased pressure on hippos for their ivory. The lower canine tusks of males are often as large as elephant tusks now entering the illegal mar- ket, and a sharp rise in the export of hippo ivory coin- cided with the placing of the African elephant under the more protective listing of appendix 1 of CITES. The Vikings were probably the first culture to ex- ploit the narwhal extensively for its tusk, which sold for high prices as early as the tenth century. The tusks were also in great demand in Asia, where they were used for carving and as medicine. During the late 1900’s, narwhal tusks were sold for as much as forty- five hundred dollars. The annual kill of narwhals in Canadian waters isestimated to be approximately one thousand. The species has received little firm protec- tion from any conservation law. Uses of Ivory For many years, the use of ivory centered around dec- orative items, such as carved figurines and various gewgaws, primarily for customers in Europe, Asia, and the United States. The manufacture of ivory piano keys and billiard balls was a major factor in the demise of both Asiatic and African elephants. Estimates indi- cated that consumption of ivory—for the making of piano keys—in Great Britain in 1831 accounted for the deaths of four thousand elephants. More modern uses of ivory have been for flatware, jewelry, and furni - Global Resources Ivory • 647 . Knowledge of this variation allows for the study of storm behavior, identification of changes in global climatic patterns, and investigation of past climatic conditions through the study of water. and granite. During the early sixteenth century, sculptor Global Resources Italy • 641 642 • Italy Global Resources Italy: Resources at a Glance Official name: Italian Republic Government: Republic Capital. existence of these extant mam- mals has been the value of their ivory. Primary Uses Ivory hasbeenusedbyhumansforthousands of years, often as a medium for carving. The art of scrimshaw makes use of ivory,