The severity of the health effects of lead contamination is only now being fully realized. Lead in the body can cause serious damage to almost all systems within the body.
The three systems where the effects are most dangerous are
· The central and peripheral nervous system
· The cardiovascular system, including the blood forming system
· The kidneys
Exposure to high concentrations of lead can cause
· Retardation
· Convulsions
· Coma
· Death (sometimes)
Children are especially vulnerable to and susceptible to lead poisoning. High levels of lead in the blood of young children can produce permanent nervous-system damage. Even at low levels, lead exposure continuing during childhood is known to slow a child’s normal development, causing learning and behavioral problems. Often, low blood lead levels do not have obvious symptoms. The Agency for Toxic Substances and Disease Registry (ATSDR), as well as numerous other investigators, reports long-lasting effects on intelligence, motor control, hearing, and emotional development of children who have levels of lead in the body that are no associated with obvious symptoms.
From 1976 to 1991 the National Health and Nutrition Examination Surveys (NHANES), an ongoing series of national examinations of the health and nutritional status of the general public, reported a significant decrease in the blood lead levels of children. Lead gasoline, soldered cans, and lead-based paint are considered major sources of lead during the period of the NHANES surveys. According to data from NHANES II and III, mean blood lead levels in children decreased 77 percent, from 13.7 µg/dL to 3.2 µg/dL. Lead source reduction is attributed to removing 99.8 percent of lead in gasoline (current regulations allow only 0.05 grams/gallon), banning lead-soldered food containers, and reducing lead in paint to 0.06 percent by weight.
Data collected during the second phase of NHANES III indicated that blood lead levels in the U.S. population continued to decrease (down to 2.3 µg/dL). Despite these declines, about one million children aged one to five years have blood lead levels greater or equal to 10 µg/dL.
Several studies evaluating the effects of lead on adults and children were published in 1996. One study evaluated the association between body lead burden and social adjustment in a population of first-grade boys. The researchers concluded that lead exposure in childhood is associated with increased risk for antisocial and delinquent behavior.
Two studies evaluating the effects of lead on adults reported a link between lead and hypertension (high blood pressure) and lead and impaired kidney function. Researchers at Harvard Medical School, Harvard School of Public Health, and the Veterans Administration studied the relationship between long-term lead accumulation and the development of hypertension. The study subjects were participants in a study of aging previously established by the Veterans Administration (now Department of Veteran Affairs) in 1961. Both blood lead levels and bone measurements were evaluated. The results indicate that long-term lead accumulation may be a significant risk factor for the development of hypertension in men.
Studies to determine whether low-level lead exposure may be associated with impaired kidney function were conducted by researchers at Harvard Medical School, Harvard School of Public Health, and the Department of Veterans Affairs Outpatient Clinic. Results of this research suggest that even low-level lead exposure may impair kidney function in middle-aged and older men.
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