15. Text 2: Plumbism Paragraph 1 Plumbism is the technical term for lead poisoning, which represent a diseased condition, produced by the absorption of lead, common among workers in this metal or in its compounds, as among painters, typesetters, etc. Lead is a metal which is toxic to humans when ingested or inhaled. When lead enters the bloodstream, whether the route of entry is the lungs or the gastrointestinal tract, it is distributed to the tissues and organs of the body, including the brain, liver and kidneys. In the long term, lead is stored in the teeth and bones. Although it is excreted gradually (mostly in the urine, but also in feces, sweat, hair and nails), repeated exposure and absorption results in an accumulation of lead in the body. Cumulative doses of lead over time can result in chronic lead poisoning, while acute lead toxicity may be observed in cases of short-term, high-dose exposures.
Paragraph 2A naturally occurring element, lead may be dispersed by natural processes such as erosion, volcanic eruptions and forest fires. Overwhelmingly, however, hazardous human exposure to lead is due to its release into the environment through industrial processes, and to the widespread use of lead-containing products, most notoriously petrol, paints, and plumbing and building materials. Many everyday household items including adhesives, batteries, ceramics, glassware and children's toys may also contain lead, particularly if manufactured in the twentieth century. Other items that have traditionally contained lead include bullets and radiation shields. Industrial sources of lead contamination of soil, water and air include mining and smelting of lead and leadcontaining ore, car manufacture and combustion of large quantities of fuels such as coal in the generation of electricity. The leading cause of lead poisoning among adults is occupational exposure, particularly for those working in the industries previously mentioned.
Paragraph 3To alleviate the incidence of environmental exposure due to contact with building materials and other products containing lead, industry guidelines and government legislation have been introduced in many countries: drinking water is no longer prone to lead contamination where alternatives to lead pipes and lead-soldered fittings, roofs and water tanks are required in new houses; maximum allowable lead content in domestic paint is now specified in a growing number of jurisdictions; and the last two decades or so have seen leaded petrol banned in most countries around the world. However, exposure to lead particles is still a significant health risk due to the lingering contamination of soil and dust from past fuel emissions, from continuing industrial exposure, and from contact with older lead-based products still in use.
Paragraph 4Even small quantities of lead taken into the body are considered hazardous to human health. Adverse systemic effects can extend to the neurological, cardiovascular, gastrointestinal and renal. Damage caused by lead poisoning is known to be irreversible in some cases, such as severe neuro-behavioral impairment resulting from acute intoxication. However, health outcomes are influenced by the timing, duration and amount of exposure (or dosage), and by how much accumulation has occurred. Among the available biological markers of lead dose, blood lead levels provide a more accurate measure if there has been recent exposure to lead, while levels of lead in bone, measuring stored lead, are more accurate indicators of accumulation.
Paragraph 5Among the most vulnerable to lead exposure and its effects are children under the age of six. Where lead is present in soil, dust, paint or toys, young children are at an increased risk of ingesting lead, as they may touch leadbased or contaminated materials with their fingers and mouths. A child's body is also more susceptible to lead absorption -it has been estimated that a child's body can absorb 50% of lead particles on exposure compared with only 10% for an adult's. The likely health effects for young children are even more dire considering the vulnerability of the developing brain to permanent disadvantage as a result of the neurotoxicity of lead. Intelligence quota (IQ) deficit has been linked to neuro-toxic effects in children with lead blood levels as low as five micrograms per deciliter (5µg/dL). Less research has been conducted on the effects of lead exposure during prenatal development but, because lead is able to cross the blood brain barrier and the placenta, the risk of significant harm to the brain and to the developing fetus is a key concern. One study in Mexico led researchers to conclude that fetal neurodevelopment is adversely affected by lead exposure and particularly so during the first trimester of pregnancy.
Paragraph 6Studies suggest that chronic lead toxicity in individuals could change behavior and cognitive function and even trigger psychosocial disturbances that contribute to aggressive behavior. One study observed a significant decline in rates of violent crime throughout the 1990s in the United States, a country where the use of leaded petrol was phased out during the 1970s. The researchers hypothesized that this change in crime rate is attributable to a reduction of childhood exposure to lead in the decades prior to the 1990s. Studies like this one, which documents an association between childhood lead exposure and criminal behavior in adults, are supported by findings that some adolescent criminals have blood lead levels quadrupling the average among teenagers. Despite these alarming health effects, the World Health Organization has described lead poisoning as a completely preventable disease.
Based on the first paragraph, lead _____