Many people believe that lead poisoning (plumbism) is a thing of the past, since one of the major sources of lead intoxication—lead-containing paint—was banned in 1978. Unfortunately, in 1995, 14 million children below the age of eight still lived in housing that contained lead paint.
In North Dakota, food pantries that distribute donated venison to the needy will now accept only archery-killed deer. Fearing that animals killed with firearms contain toxic lead fragments, the state’s health department has ordered that these carcasses be discarded. (North Dakota Ruling)
Lead poisoning has been a public health issue for centuries. Since the 1950s, research in the United States has demonstrated deleterious effects of even low levels of lead exposure. Lead poisoning is defined as a blood lead level at or above 10 µg per dL. In 2002, 4.4% of preschool-aged children in the US had lead levels above 10 µg per dL; for every 10 µg per dL increase in lead levels, IQ test scores decrease by two to three points. (Ellis, M and Kane, K. Lightening the lead load in children. Am Fam Physician 2000;62:545-54,559-60)
Sources of Exposure to Lead
Lead is primarily absorbed by ingestion or inhalation of dust particles. Historically, lead paint has been the primary source of exposure for children, although contributions from living in industrial areas or residing with an adult with a high-risk occupation add to the burden.
Children are more susceptible to lead intoxication due to their relatively more permeable blood-brain barrier and incomplete neurologic development. Toddlers experience heightened exposure because of their proximity to contaminated dust in carpets and their tendency to ingest lead-containing debris.
In adults, occupational exposure is the main source of intoxication (welding, firing range maintenance, stained glass work, mining, glass blowing, shipyard work, ceramic glazing, and battery manufacturing). Lead-glazed dishes and contaminated foodstuffs (e.g., contaminated supplements and folk remedies, homemade alcohol) contribute to exposure.
Signs and Symptoms of Lead Poisoning
- Neuro-developmental abnormalities are prominent in children (attention deficit disorder, behavioral disturbances, learning disabilities, and deficits in both fine and gross motor development)
- Nephropathy (kidney damage)
- Hypertension (as a result of kidney involvement in chronic lead intoxication)
- Anemia (red blood cells contain dark granules, known as “basophilic stippling”)
- Defects in vitamin D metabolism (potentially leading to abnormal bone development in children)
- Neuropathy (numbness, tingling, burning or pain)
- Nausea, vomiting, or abdominal pain
- Back pain
- Limb weakness
- General malaise
- At lead levels above 70 µg per dL, increased intracranial pressure, encephalopathy (coma or near-coma), seizures, and death can occur
Treatment of Lead Poisoning
Treatment for lead poisoning is tailored to the severity of intoxication and is centered on lowering blood levels of lead. Several medications that chelate lead and remove it from the bloodstream are available.
However, since lead has a long half life and tends to persist in soft tissues and bones, chelation therapy may not significantly reduce whole-body lead levels. Retreatment may be necessary.
Exposure abatement is a key to successful treatment. Worksite evaluation, removal or covering of lead paint, the use of HEPA filters in vacuums, inspection of pottery and dishware, and avoidance of contaminated food items are all important measures. (Rhoads G, et al. The effect of dust lead control on blood lead in toddlers. Pediatrics 1999;103:551-555)
Lead poisoning remains a significant health concern. Since its symptoms and signs may be subtle in early stages or at low levels of exposure, screening is recommended for all children at risk (e.g., in low-income housing or areas where lead intoxication has already been discovered) and in adults in high-risk occupations.
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