Lead And The Environment :: essays research papers

Lead and The Environment Some materials are so commonplace that we take them for granted. One of those materials is a grayish metal that has been with us for thousands of years. That metal is lead, still one of the world's most useful substances, and one that never ceases to find a role in human society.   Ã‚  Ã‚  Ã‚  Ã‚  Lead has the atomic symbol of Pb (for plumbum, lead in Latin). The atomic number for lead is 82 and the atomic mass is 207.19 AMU. It melts at about 327.502 oC and boils at 1740 oC. Lead is a heavy, ductile, soft, gray solid. It is soluble in nitric acid and insoluble in water. It is found in North, Central and South America, Australia, Africa and Europe. In modern times, lead has found a wide range of uses, and world demand for lead and its products has steadily increased. Lead's usefulness stems from the metal's many desirable properties: softness, high density, low melting point, ability to block radiation, resistance to corrosion, readiness to form alloys and chemical compounds, and ease of recycling. Its versatility, as well as its physical and chemical properties, accounted for its extensive use. Lead can be rolled into sheets which can be made into rods and pipes. It can also be molded into containers and mixed with other metallic elements.   Ã‚  Ã‚  Ã‚  Ã‚  Lead was used in ancient times for making coinage, art objects and water pipes. One of the first known toxic substances, lead was used by the Romans for lining aqueducts and in glazes on containers used for food and wine storage; and it is suspected to have resulted in widespread lead poisoning. Members of the famous Franklin Expedition to the Northwest Passage in the mid-1840s met a similar fate, being poisoned from lead in solder, widely used at the time to seal tins used to store foods. Until recently, one of the most significant uses was an anti-knock additive in gasoline. In the 1970s and 1980s, steps were taken to reduce the use of leaded gas. By 1990, these actions had virtually eliminated the use of lead in gasoline. Lead is also one of the best and earliest examples of recycling about 55 percent of the lead used in Canada comes from recycled material.   Ã‚  Ã‚  Ã‚  Ã‚  One particular category of toxic tort is injury caused by exposure to lead-based paint. The hazards of lead-based paint have been known since the early 1900s, when the use of lead in the manufacture of paint was banned in Australia. The lead mining and lead pigment industries in the United States were able, however, to forestall the banning the use of lead in the manufacture of