Nitrates

Nitrogen, an essential element for the life of plants, and of living beings in general, constitutes four-fifths of the earth's atmosphere. In spite of its abundance, the capacity of plants to fix nitrogen, that is, to take it from the atmosphere or the soil and convert it into carbohydrates, amino acids, and proteins, is extremely variable, and therefore land devoted to crops can require the direct application of nitrogen to preserve or increase its fertility. Nitrates, nitric acid salts, were the first natural fertilizers to be used for this purpose.

Nitrates were first described by T. Haenke, a naturalist engaged in the expedition led by the Spanish scientist Alejandro Malaspina (1754–1810) in 1798. It was not until the early decades of the nineteenth century, however, that the commercial exploitation of the vast deposits of soda nitrate (NaNO3)—the greatest in the world—in seaward regions of Peru, Bolivia, and, especially, Chile (where it is known as salitre) began, when it was carried out to obtain potash nitrate for the manufacturing of gunpowder. Some nitrate was sent to England, the United States, France, and Holland for this purpose in the 1820s and 1830s.

By the 1840s the discovery of the principles governing the growth of plants by scientists such as Jean Baptiste Boussingault (1802–1887) and Justus von Liebig (1803–1873), and the results obtained on the most prestigious experimental farms of the day, led to the application of Chilean nitrate as the main natural fertilizer used by European and North American farmers to ensure the necessary nitrogen for their crops. Around the same time, the emergence of more highly developed procedures for obtaining potash nitrate from soda nitrate—such as that patented by F. C. Hills in England in 1846—and the possibility of obtaining iodine as a by-product, gave rise to a significant increase in the demand for nitrate. As a result, Chile's exports of soda nitrate, which had scarcely reached 10,000 tonnes (metric tons) in 1840, grew dramatically, reaching 100,000 tonnes by the mid-1860s, 1 million tonnes by the mid-1890s (when virtually all nitrate deposits had been placed under Chilean control after the Pacific War, 1879–1883) and almost 3 million tonnes in 1913. This rapid growth in exports was favored by the progressive reduction in sea-freight costs in the course of the nineteenth century. During this period, Chilean nitrate enjoyed a virtual monopoly of world markets.

The exploitation of the nitrate deposits, the processing of the mineral, and its transportation to the coast and subsequent shipping to the centers of consumption in Europe and the United States involved the intervention of foreign capital and engineers. By the end of the nineteenth century most of the production and exportation of nitrates was in British and German hands. The marketing of the mineral, including transportation and the involvement of import-export agencies, was also controlled by European and, to a lesser extent, North American companies. The Chilean government, for its part, also managed to secure a considerable part of the profits generated by the nitrate business. The 2-shilling tax on every Spanish quintal (46 kilograms) of nitrate exported represented over 50 percent of the Chilean treasury's ordinary revenues between 1890 and 1918.

WORLD WAR I

The outbreak of World War I drastically affected the nitrate business. The British blockade of German ports—through which not only German, but also Central European consumers traditionally received their supplies—and the restrictions on the re-exporting of nitrate from London, because of its use in the manufacturing of explosives, led to a 30 percent reduction in Chilean exports between 1913 and 1914. These difficulties presented the final incentive to develop new procedures to obtain synthetic nitrogen.

By 1914 the position of Chilean nitrate was threatened by the ammoniac sulfate obtained in the factories of the most heavily industrialized countries from the distilling of soft coal or from coal recovered from the furnaces used to transform it into foundry coke. But what really revolutionized the world nitrogen market was the discovery in 1913 of a new process, known as the Haber-Bosch process, to obtain nitrogen from the air. Thanks to this development, Germany not only managed to become self-sufficient in nitrogen but was also able to establish itself as an important exporter in the 1920s, becoming the world's top exporter, ahead of Chile, in 1932.

Meanwhile, the most significant events in the history of Chilean nitrate in the 1920s, with the exception of the growing competition from synthetic nitrate, were the

Guggenheim family's move into the sector and, in the final analysis, the reinforcing of North American economic interests in Chile. However, the collapse in prices—which fell 15 percent from U.S.$43.12 a metric ton in 1926 to U.S.$36.78 in 1929—ruined the Guggenheims' initial prospects and left the Chilean nitrogen industry on the verge of collapse. The creation of a new company, COSACH (Compañía de Salitre de Chile), in 1931 could not prevent a reduction in the consumption of fertilizers and a fall in prices—which continued until they reached U.S.$18.80 a ton in 1934—from ruining all forecasts. In 1933 COSACH was dissolved. The era of Chilean nitrate was over.

The use of nitrogenous fertlizers has continued to increase since the end of World War II. At the beginning of the 1960s the figure worldwide surpassed 10 million tonnes, in the second half of the 1970s 50 million, and in 2000 over 80 million. Alongside the growth in production and consumption there has also been a radical change in the geography of the market. The world's main producers of nitrogenous fertilizers in the year 2000 were China and India, with 22 and 11 million tonnes respectively. China and India are also at the forefront in terms of absolute consumption. In that same year the main exporter of nitrogenous fertilizers in the world was the Russian Federation, with more than 4 million tonnes, and the main importer the United States, with 6.6 million.

SEE ALSO Agriculture; Cargoes, Freight; Chile; Guggenheim Family;Mining;Shipping Lanes;Shipping, Merchant.

BIBLIOGRAPHY

Couyoumdjian, Ricardo. "El mercado del salitre durante la Primera Guerra Mundial y la postguerra, 1914–1921. Notas para su estudio." Historia 12 (1974): 13–55.

O'Brien, Thomas F. "'Rich Beyond the Dreams of Avarice': The Guggenheims in Chile." Business History Review 63 (Spring 1989): 122–159.

Plumpe, Gottfried. Die I.G. Farbenindustrie AG. Wirtschaft, Technik, Politik. 1904–1945. Berlin: Duncker and Humblot, 1990.

José-Ignacio Martínez Ruiz

NITRATES

NITRATES. Nitrate (NO₃) is a compound of the elements nitrogen and oxygen. Nitrates are important to all living systems. Plants, especially, require it to develop and produce seeds. Nitrogen, the main component of Earth's atmosphere, is a relatively inert substance. To be useful, it must be converted into active forms. Lightning and radiation create nitrates in the atmosphere, where rainstorms carry them to the ground. Bacteria on roots of crops such as alfalfa and clover fix nitrogen in the soil. Microorganisms form nitrates as they break down animal matter. Since the early twentieth century, nitrates have been produced industrially.

Nitrates are present naturally in sewage and in some mineral deposits. Chile's Atacama Desert is the world's leading supplier of the mineralized form. Approximately 86 percent of the nitrate produced in the United States is used for fertilizer, though the chemicals have other uses. Potassium nitrate (KNO 3), also known as saltpeter, is the key ingredient in gunpowder. Saltpeter is formed naturally in warm climates by bacteria decomposing accumulations of excreta and animal refuse. Contact among putrefying material, alkaline soil, plant ashes, air, and moisture causes nitrates to form and penetrate the ground. After evaporation of rainwater, saltpeter appears as white powder on the surface.

Since the temperate climates of Europe and North America did not favor the formation of saltpeter, its supply was a vital concern for American colonists. European countries obtained saltpeter from India. When the American Revolution cut off the colonies from this source, some colonial governments offered bounties and established "artificial nitrate works, " without much success. France saved the Continental Army from running out of gunpowder after having taken great pains to develop its own domestic supply. In the early nineteenth century, salt-peter was discovered in large quantities in caves in Kentucky and Tennessee. This resource helped fuel the Confederate armies during the American Civil War, though 90 percent of their powder likely came from foreign sources that managed to get through the Union blockade. After this period, the United States and Europe imported nitrate from Chile.

As the nineteenth century progressed into the twentieth, demand for nitrate fertilizers increased dramatically. Many countries experimented with methods of converting atmospheric nitrogen. All processes seemed expensive and complex. The outbreak of World War I drove the United States to attempt its own synthetic production by 1917. In preparation, a hydroelectric dam was built at Muscle Shoals, Alabama. Soon after, the process introduced in Germany by Fritz Haber in 1912 proved its superiority and the power plant was abandoned. In the 1930s, it became the foundation of the Tennessee Valley Authority.

Nitrates have become an environmental concern. Elevated levels of nitrogen flowing down the Mississippi River enter the Gulf of Mexico and nourish algal blooms. When algae die and decompose, they consume oxygen, depleting that vital element from the water. Fish and other creatures suffocate in affected areas that can cover thousands of square miles, causing problems for commercial fishing and other coastal industries. Sources of the nitrogen include sewage treatment water, industrial wastes, and atmospheric pollutants; large loads also come from livestock operations and nitrate fertilizer runoff from farm-land. Nitrates infiltrate ground water as well as surface waters. According to the Environmental Protection Agency, when nitrates are present in quantities in excess of ten milligrams per liter, the water supply can pose a potentially fatal threat to infants under six months and to young and pregnant animals.

BIBLIOGRAPHY

Hill, Michael J., ed. Nitrates and Nitrites in Food and Water. New York: Ellis Horwood, 1991.

Keleti, Cornelius. Nitric Acid and Fertilizer Nitrates. New York: Dekker, 1985.

Wilson, W. S., A. S. Ball, and R. H. Hinton. Managing Risks of Nitrates to Humans and the Environment. Cambridge: Royal Society of Chemists, 1999.

Robert P.Multhauf

Christine M.Roane

See alsoFertilizers .

nitrates Plant nutrients and natural constituents of plants; found in soils and included in fertilizer. The amount in crops depends on the amount in soil. Found in drinking water as a result of excessive use of fertilizers.

Health problems can arise because within a day or two of harvesting some crops nitrates are converted into nitrites which can react with the haemoglobin (especially fetal haemoglobin) in the blood to produce methaemoglobin which cannot transport oxygen. Maximum levels have been established for nitrate levels in drinking water (an upper limit of 45–50 mg nitrate/L has been recommended for infants).

Nitrates are also used, together with nitrites, for curing meat products. See also nitrosamines.

nitrate A salt or ester of nitric acid. The salts contain the ion NO₃^–.

nitrates (ny-trayts) pl. n. a class of drugs used as coronary vasodilators for the treatment and prevention of angina attacks. They include glyceryl trinitrate, isosorbide dinitrate, and isosorbide mononitrate.