I need information about lead poisoning

Compliments of the season our able and committed doctor. Not long ago, I was informed there was lead poisoning in some northern states. I need simplified information about it and the damage it can inflict on human beings.

Jatau S.

Thanks Jatau for your question about lead poisoning. To begin with, “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.

The important sources of environmental contamination include mining, smelting, manufacturing and recycling activities, and, in some countries, the continued use of leaded paint and leaded gasoline. More than three quarters of global lead consumption is for the manufacture of lead-acid batteries for motor vehicles.

Lead is, however, also used in many other products, for example pigments, paints, solder, stained glass, crystal vessels, ammunition, ceramic glazes, jewellery, toys and in some cosmetics and traditional medicines.

According to the World Health Organisation ( WHO), the following provide succinct information about lead poisoning:

1. “Lead is a cumulative toxicant that affects multiple body systems and is particularly harmful to young children.

2. Lead in the body is distributed to the brain, liver, kidney and bones. It is stored in the teeth and bones, where it accumulates over time. Human exposure is usually assessed through the measurement of lead in blood.

3. There is no known level of lead exposure that is considered safe.

4. Lead poisoning is entirely preventable.”

It has being reported that young children are particularly vulnerable to the toxic effects of lead and can suffer profound and permanent adverse health effects, particularly affecting the development of the brain and nervous system. Lead also causes long-term harm in adults, including increased risk of high blood pressure and kidney damage. Exposure of pregnant women to high levels of lead can cause miscarriage, stillbirth, premature birth and low birth weight, as well as minor malformations.

Some sources and routes of exposure are:

People can become exposed to lead through occupational and environmental sources. This mainly results from:

1. Inhalation of lead particles generated by burning materials containing lead for example during smelting, informal recycling, stripping leaded paint and using leaded gasoline; and

2. Ingestion of lead-contaminated dust, water (from leaded pipes), food (from lead-glazed or lead-soldered containers).

3. The use of some traditional cosmetics and medicines can also result in lead exposure.

Young children are particularly vulnerable because they absorb 4-5 times as much ingested lead as adults from a given source. Moreover, children’s innate curiosity and their age-appropriate hand-to-mouth behaviour result in their mouthing and swallowing lead-containing or leadcoated objects, such as contaminated soil or dust and flakes of decaying leadcontaining paint.

This route of exposure is magnified in children with pica (persistent and compulsive cravings to eat non-food items), who may, for example pick away at, and eat, leaded paint from walls, door frames and furniture.

Once lead enters the body, it is distributed to organs such as the brain, kidneys, liver and bones. The body stores lead in the teeth and bones where it accumulates over time. Lead stored in bone may be remobilized into the blood during pregnancy, thus exposing the fetus.

Lead has also had serious consequences for the health of children.

• At high levels of exposure, lead attacks the brain and central nervous system to cause coma, convulsions and even death.

• Children who survive severe lead poisoning may be left with mental retardation and behavioural disruption.

• At lower levels of exposure that cause no obvious symptoms, and that previously were considered safe, lead is now known to produce a spectrum of injury across multiple body systems.

• In particular lead affects children’s brain development resulting in reduced intelligence quotient (IQ), behavioural changes such as shortening of attention span and increased antisocial behaviour, and reduced educational attainment.

• Lead exposure also causes anaemia, hypertension, renal impairment, immunotoxicity and toxicity to the reproductive organs. The neurological and behavioural effects of lead are believed to be irreversible.

Lead poisoning is preventable if all the potential sources and causes itemized above are removed.