Lead poisoning

Leadpoisoning is a condition, also known as plumbism or painter's colic, caused by increased blood serumlead levels.

History

Lead was first mined in Turkeyabout 6500 BC. A 6000- to 8000-year-old necklace was found in the ancient city site of Anatolia. Lead's easy workability, low melting point and corrosion resistance were among its attractions.

Lead toxicity was first recognized as early as 2000 BC. Nikander of Colophonwrote of lead-induced anemiaand colicin 250 BC. Gout, prevalent in affluent Rome, is thought to be the result of lead, or leaded, eating and drinking vessels. Lead was also used in makeup.

In 17th-century Germany, an Ulmphysician noticed that monks who did not drink wine were healthy, while wine drinkers developed colic. The culprit was a white oxide of lead, litharge, added to sweeten the wine.

Today, most exposure in developed countries is the result of occupational hazards, leaded paint, and leaded gasoline(in the US, phased out in the 1970s).

Symptoms and effects

The symptoms of lead poisoning include neurological problems, such as reduced IQ, nausea, abdominal pain, irritability, insomnia, excess lethargyor hyperactivity, headacheand, in extreme cases, seizureand coma. There are also associated gastrointestinal problems, such as constipation, diarrhea, abdominal pain, vomiting, poor appetite, weight loss. Other associated affects are anemia, kidney problems, and reproductive problems. In humans, lead toxicity often causes the formation of bluish line along the gums, which is known as the "Burtons's line " A direct link between early lead exposure and extreme learning disabilityhas been confirmed by multiple researchers and child advocacygroups.

Biological role

Lead has no known biological role in the body. The toxicity comes from its ability to mimic other biologically important metals, the most notable of which are calcium, ironand zinc. Lead is able to bind to and interact with the same proteinsand moleculesas these metals, but after displacement, those molecules function differently and fail to carry out the same reactions, such as in producing enzymesnecessary for certain biological processes.

Most lead poisoning symptoms are thought to occur by interfering with an essential enzymeDelta-aminolevulinic acid dehydratase, or ALAD. ALAD is a zinc-binding protein which is important in the biosynthesis of heme, the cofactor found in hemoglobin. Genetic mutations of ALAD cause the disease porphyria, a disease which was highlighted in the movie The Madness of King George.

Occurrence

Outside of occupational hazards, the majority of lead poisoning occurs in children under age twelve. The main sources of poisoning are ingestion of lead contaminated soil(this is less of a problem in countries that no longer have leadedgasoline) and lead based paints. This is particularly a problem in older houses where the sweet-tasting lead paint is likely to chip. In most American states, landlords and those selling such houses are required to inform the potential residents of the danger.

Measurement

One measure of lead in the body is the blood lead level(BLL), measured in micrograms of lead per deciliter of blood(μg/dL). Nearly everyone has a measurable BLL. The Centers for Disease Control and Prevention(CDC) states that a BLL of 10 μg/dL or above is a cause for concern. However, lead can impair development even at BLLs below 10 μg/dL.

The average person has less than 10 microgramsper deciliter, or 100 parts per billion, ppb, of lead in their blood serum. People who have been exposed to an unusual amount of lead will have lead serum levels higher than 200 ppb—most clinical symptoms of lead poisoning begin at around 100 ppb.

Treatment

Although the most important part of treating lead poisoning is decreasing exposure to lead, there are some forms of chelation therapythat can be used to reduce existing BLL levels:

• DMSA
• EDTA
• British anti-Lewisite

Famous cases of lead poisoning

• Much of Rome's affluent class suffered from lead-induced gout
• The Devon colicwas caused by the presence of lead in ciderin 18th century Devon.
• Many historians have believed that Ludwig van Beethovensuffered from lead poisoning. This belief has been confirmed in 2005by tests done at Argonne National Laboratoryin the US on skull bone fragments, confirming earlier tests on hair samples.
• Lead shotfor hunting has been banned in many countries because waterfowl often ingest spent shot, which kills some in a matter of weeks.
• Operation of a smelter in Trail, British Columbiacontributed to higher than average blood lead levels in children living in Trail compared to nearby communities. A monitoring program, funded by the smelter and two level of government was established.

See also

• Lead: Precautions

External links

• Case Studies in Environmental Medicine (CSEM): Lead Toxicity
• National Pollutant Inventory - Lead and Lead Compounds Fact Sheet
• Helping Parents Prevent Lead Poisoning
• Argonne Lab confirms Beethoven lead poisoning, Dec. 2005
• History of lead poisoning in the world

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This article is licensed under the GNU Free Documentation License.
It uses material from the http://en.wikipedia.org/wiki/Lead+poisoning Wikipedia article Lead poisoning.