M9.4 Heavy Metals

Lead is a naturally occurring toxic metal found in the Earth’s crust. Its widespread use has resulted in extensive environmental contamination, human exposure and significant public health problems in many parts of the world. Important sources of environmental contamination include mining, smelting, manufacturing and recycling activities, and, in some countries, the continued use of leaded paint, leaded gasoline, and leaded aviation fuel. More than three quarters of global lead consumption is for the manufacture of lead-acid batteries for motor vehicles.

Lead toxicity was examined first for workers who were exposed to high-dose and have symptomatic effect. In recent years, the focus was shifted toward children who are exposed to low-dose of lead. Central nervous system is the most affected system by lead toxicity in addition to distortion of enzymes and structural proteins.

Children are more sensitive to lead than adults for several reasons: Their exposure is increased by their universal hand-to-mouth activity; their gut absorbs lead more readily than an adult’s; and the developing CNS is more vulnerable to toxicants than the mature CNS. Any child with growth failure, abdominal pain, behavior change, hyperactivity, language delay, or anemia should have a blood lead test to rule out lead toxicity.