Lead Essay ⋆ Environment Essay Examples ⋆ EssayEmpire

This Lead Essay example is published for educational and informational purposes only. If you need a custom essay or research paper on this topic, please use our writing services. EssayEmpire.com offers reliable custom essay writing services that can help you to receive high grades and impress your professors with the quality of each essay or research paper you hand in.

Lead is a soft, heavy, and toxic metal. It is easy to extract and smelt, and is well-suited for many uses. The combination of lead’s toxicity with its usefulness has proved to be a particularly hazardous pairing: lead is an extremely toxic and also ubiquitous environmental contaminant.

Lead has been employed throughout history in a variety of ways: in plumbing, paint, gasoline, leadacid batteries, ceramic glazes, jewelry, glass, wine, firearm projectiles, lead solder, and radiation shielding. Lead has been used by humans for at least 7,000 years. The most memorable appearance of lead historically was in water pipes and wine in the Roman Empire.

Lead is toxic in the body because it is able to mimic other biologically-important metals (such as iron, calcium, and zinc) and thereby interfere with biological processes. The adverse health effects of lead are numerous. They include (but are not limited to): reduced IQ, developmental delays in children, other neurological problems, hearing impairment, hypertension, lethargy, hyperactivity, infertility, anemia, gout, colic, brain damage, seizure, coma, and death. The adverse effects of lead have been recognized for thousands of years. The Romans themselves attributed the prevalence of gout and dementia to lead toxicity. It is likely that Beethoven suffered from lead poisoning.

Acute lead poisoning encompasses a certain set of symptoms, occurring at particularly high levels of exposure (usually blood lead levels above 20 µg/ deciliters). It is now widely agreed, however, that exposure to lead at any level is toxic. Lead exposure is especially dangerous to young children because they absorb more lead from their environment and are at a critical stage of their neurobehavioral development. It was not until after 1950 that it was widely accepted that the neurological effects of lead poisoning persist and that lead exposure is dangerous even at low levels.

Lead has a long and illustrious history. While Roman aristocrats acknowledged risks such as madness and death from significant lead exposure, they falsely believed that moderate exposure would not be harmful. Many historians argue that chronic lead poisoning was a major factor in the decline of the Roman Empire. From the Middle Ages through the Industrial Revolution, lead was employed widely in alchemy, printing, weapons, and other industry. By the 20th century, the United States was the leading producer and consumer of refined lead. The per capita usage in the United States in 1980 was approximately 10 times that in Ancient Rome.

Currently, the primary environmental sources of lead exposure are leaded gasoline and lead-based paint. Industry presents an additional source of lead exposure, but such exposure is largely confined to those who live near or work in lead-producing industries such as lead smelters, battery plants, or fuel-burning industrial facilities.

Tetraethyl lead was first added to gasoline in the 1920s to improve engine performance and reduce engine knock. Early in the use of lead, General Motors refinery workers fell sick and died. Despite the warnings of public health advocates (including Harvard professor Alice Hamilton) and journalists (who dubbed leaded gas “loony gas”), lead was approved for use in gasoline. In the following decades, the lead content of gasoline rose, as did the use of gasoline in automobiles. By the 1950s there was an average of 2.4 grams of lead per gallon of gasoline. Lead from gasoline is absorbed into the body directly by breathing in gasoline exhaust and indirectly from contact with lead deposits in soil.

In the early 1970s the newly formed U.S. Environmental Protection Agency (EPA) officially recognized lead as a substantial public health hazard and named gasoline “the most ubiquitous source of lead found in the air, dust, and dirt in urban areas.” In 1974, under the authorization of the Clean Air Act, the EPA mandated a timetable for the reduction of lead in gasoline, requiring petroleum companies to meet specified targets of maximum grams of lead per gallon of gasoline. The average lead content of the gasoline produced by each refinery was to be reduced from 2.0 grams per total gallon to a maximum of 0.5 grams per total gallon by 1979. This time table was delayed somewhat, and further reductions implemented. By 1990, gasoline lead had dropped to a mere one percent of its 1975 levels.

Most countries in western Europe followed the United States, using a variety of financial incentives to remove lead from gasoline in the 1980s and 1990s. Worldwide, however, many countries still use leaded gasoline; as of 2005, 67 countries had not yet banned or phased out lead from gasoline. These countries are generally poorer and located in central Europe, eastern Europe, Africa, Southeast Asia, and the Middle East.

Lead in paint is the second major source of environmental lead exposure. Lead was originally added to paint as a pigment and to speed drying and increase durability. Many countries banned lead in residential uses early in the 1920s, but the United States did not do so until 1978. In the United States, the lead content of paint declined relatively smoothly from 1920 on, with breaks in 1950 when leadbased paint was banned for interior use and in 1978 when it was banned for all residential uses. Lead paint is still used by the military and industry.

Lead in paint is not as readily absorbed as lead from gasoline. Currently, the primary danger stems from older housing with deteriorating paint: the main exposure pathway is via normal hand-tomouth contact with lead dust. Children also may eat paint chips (because lead makes paint taste sweet). Exposure to lead in paint dust and paint chips represents a significant source of current environmental lead exposure for children. The U.S. government has a variety of programs aimed at increasing parental awareness of the hazards of lead exposure. Many states have residential lead paint regulations that mandate removal or abatement of lead paint in housing occupied by young children.

There is also emerging evidence that lead used in water mains throughout the world presents an additional hazard. Research suggests that water may leach lead from these pipes (either in mains or in residential pipes), providing a steady stream of lowlevel and largely undetected exposure to lead.

The U.S. experience – a drastic decline in blood lead levels since the 1970s – is widely viewed as a strong success of public health policy. The decrease was brought about by the work of advocacy groups, government agencies, and scientists such as the pioneer Herbert Needleman. This success, however, was not easily achieved: these groups and individuals overcame significant resistance from the paint and petroleum industries. While much has been achieved, hazards remain both in the United States and around the world.

The current public health focus in the United States is on the hazards posed by existing lead paint and the higher likely impact on children of lower socioeconomic status. In addition, many of the psychological effects of childhood lead exposure can persist into adulthood, potentially producing higher rates of adverse social behavior on a societal scale decades after the actual exposure. By affecting societal phenomena, such as learning disabilities and violent crime, lead may in fact have a larger impact on society than has been generally acknowledged.

Worldwide, lead contamination persists, and public health agencies and governments are taking important steps to reduce environmental lead exposure. The removal of lead from gasoline continues, particularly in central and eastern Europe and Southeast Asia. The challenge often encountered is the persistence of deposition from historical usage and the presence of lead in paint. The policy problem, particularly for poorer countries, is that the initial costs of removal may seem high relative to the less tangible and possibly distant health benefits. While the benefit – cost ratios are uniformly high (usually greater than 10), lead contamination presents a challenge for policy implementation.

Bibliography:

David Bellinger, Lead (Pediatrics, 2004); Richard Lansdown and William Yule, , Lead Toxicity: History and Environmental lmpact (Johns Hopkins University Press, 1986);
Magda Lovei, Phasing Out Lead from Gasoline: Worldwide Experience and Policy lmplications (World Bank, 1998);
Jerome O. Nriagu, Lead and Lead Poisoning in Antiquity (John Wiley & Sons, 1983);
Julie Wakefield, Lead History-Violent Future (Environmental Health Perspectives, 2002).