Lead is the commonest metal involved in chronic poisoning. Lead is a natural component of the earth's crust with trace amounts existing in soil, water and plants.
Environmental sources of lead may be from air, food and water pollution. The main sources of lead exposure are paints, water, food, dust, soil, kitchen utensils, and leaded gasoline.
Lead is highly persistent in the environment and because of its continuous use its levels rise in almost every country, posing serious threats. It does not dissipate, nor is it biodegradable. Therefore, lead in dust becomes a long-term source of lead exposure.
Lead is a poison that affects virtually every system in the body. The toxicity in children is however of a greater impact than in adults. This is because their tissues, internal as well as external, are softer than in adults. Long-term exposure of adults can result in decreased performance in some tests of cognitive performance that measure functions of the nervous system.
Chronic poisoning: Children show weight loss, weakness, and anemia. The first signs in children may be subtle neuro-behavioral deficits adversely affecting classroom behavior and social interaction. Adults manifest vague gastrointestinal and CNS complaints; wrist drop and colic rarely occur.
At high levels of acute exposure, lead attacks the brain and central nervous system to cause coma, convulsions and even death. Children who survive acute lead poisoning are typically left with grossly obvious mental retardation and behavioral disruption.
Lead toxicity
