Lead Poisoning

What is it?

Lead poisoning is a preventable condition that results from environmental or occupational exposure to lead. This exposure can result in permanent health damage, especially among children.

Lead poisoning can affect almost all parts of the body, including the central nervous system, kidneys, and reproductive organs. It commonly causes weakness and abdominal discomfort and less often causes abdominal pain, vomiting, constipation, foot and wrist drop and anaemia. In children especially, it impairs cognitive development, which can lead to learning disabilities and behavioural problems. At very high levels, it can even result in hallucinations, coma, seizures, and death.

Environmental lead exposure comes from inhaling or ingesting lead laden dust. This can come from sources such as deteriorated paint containing lead found in older houses. Drinking water can also be contaminated if plumbing parts, such as pipes, are made of lead. Recent reports have included exposure from imported folk remedies, health foods, cosmetics and toys that have been contaminated with lead. Children are especially vulnerable to lead poisoning as they have an increased hand to mouth behaviour which may include ingestion of lead contaminated items such as soil and paint chips. There is also an increased risk of lead exposure to a developing foetus if pregnant women are exposed.

As poisoning from lead became known as a problem, lead began to be removed from paint products and unleaded petrol was introduced. Following these and other measures, there has been a significant reduction in blood lead concentrations in the general population of the UK and many other countries.

Adult lead exposure is usually either from the workplace or from hobbies. Children may be affected if contaminants are brought home from the workplace on clothing. Examples of situations potentially leading to lead exposure are listed below:

Work Settings

lead smelting plants
construction work
steel welding
bridge reconstruction
firing range instructors and cleaners
remodelling and refinishing
foundry work
scrap metal and battery recycling
auto repair work
cable splicing and
battery, glass and ceramic ware manufacture

In England and Wales the Health and Safety Executive requires some 15,000 workers to be regularly monitored for lead poisoning.

Hobbies

casting bullets, lead shot or fishing sinkers
home remodelling
target shooting at firing ranges
lead soldering
auto repair work
stained glass work and
glazed pottery work

About Lead Poisoning

Tests

A simple blood lead test can be done to detect the level of lead in your body. Sometimes a second test, called a zinc protoporphyrin (ZPP) test, is requested. The ZPP result increases when lead interferes with red blood cell’s ability to make haemoglobin. Some experts question the value of ordering both tests at once, and the ZPP test is not reliable for screening children for lead poisoning.

In 1997, the Centers for Disease Control and Prevention (CDC) issued revised screening guidelines for all children for elevated blood lead, except those in communities or neighbuorhoods found not to be at risk. The CDC released guidelines for action, including testing intervals, for blood lead levels in children.
Treatment

Treatment of lead poisoning depends on the concentration of lead in the blood and symptoms. The most common treatment is to identify the source of lead and to eliminate or reduce further exposure. Efforts to reduce exposure to lead may include wet mopping living areas frequently and flushing water from the tap before drinking if lead pipes are present. Lead abatement of a house is the process of methodically removing lead paint or other lead sources from a building or area and is usually performed by trained professionals. Workers exposed to lead in their jobs may have to wear respirators. If lead is still building up in their bodies, they may be transferred to a job with lower levels of lead exposure. Abatement at the work site may be required if blood lead levels are very high among employees.

Chelation therapy is a last resort treatment to rid the body of high amounts of lead. Chelation involves giving a patient a chemical which lead will preferentially bind to and then be excreted in the urine. Sodium calcium edetate is effective but has to be given into a vein. Dimercaptosuccinic acid has the advantage that it can be given by mouth and is often used in small children. Chelation treatment can be dangerous because the chemical-lead combination can damage kidneys.