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Lead poisoning

Category: Illness or disabilities

Type

Involuntary

Introduction and description

Lead poisoning is caused when the heavy metal lead enters the body. It can be accidentally ingested, but it can, as organic lead compounds, cross the skin and respiratory tract easily. Thus there are multiple routes of exposure.

Lead has no known physiologically relevant role in the body, and its harmful effects are myriad.  Lead is extremely toxic at any level and interferes with the heart, bones, intestines, kidneys, and reproductive and nervous systems. It can also enter the brain via the spinal cord and affect the organs of the brain.

The main body compartments that store lead are the blood, soft tissues, and bone; the half-life of lead in these tissues is measured in weeks for blood, months for soft tissues, and years for bone.  The estimated half-life of lead in bone is 20 to 30 years, and bone can introduce lead into the bloodstream long after the initial exposure is gone.

It is removed from the body very very slowly, mainly through urine. Smaller amounts of lead are also eliminated through the faeces, and very small amounts in hair, nails, and sweat. 

Lead poisoning is one of the oldest known work and environmental hazards, the modern understanding of the small amount of lead necessary to cause harm did not come about until the latter half of the 20th century. But its harmful effects have been known for thousands of years.  In the 2nd century BC the Greek botanist Nicander described the colic and paralysis seen in lead-poisoned people. Dioscorides, a Greek physician who lived in the 1st century CE, wrote that lead makes the mind "give way".

No safe threshold for lead exposure has been discovered—that is, there is no known amount of lead that is too small to cause the body harm.

Lead is one of the largest environmental medical problems the world faces in terms of the numbers of people exposed and the public health toll it takes. Lead exposure accounts for about 0.2% of all deaths and 0.6% of disability adjusted life years globally, but this figure is probably a very conservative estimate.

Of North American children, 7% have unacceptable levels of lead in their blood.  Among Central and South American children, the percentage is 33 to 34%. About one fifth of the world's disease burden from lead poisoning occurs in the Western Pacific, and another fifth is in Southeast Asia.

In one of the weirdest statements I saw in Wikipedia is the sentence…

“Recommendations by health professionals for lowering childhood exposures include banning the use of lead where it is not essential [sic!] and strengthening regulations that limit the amount of lead in soil, water, air, household dust, and products”. 

How can anything this poisonous be called ‘essential’?  All heavy metals cause horrendous health problems, but lead has a terrible history.  I’m afraid I find it extraordinary that it hasn’t been banned entirely years and years ago.

Symptoms

Lead poisoning creeps up on you.  If the exposure is small there is a correspondingly slow development of symptoms such that people may not notice anything happening.  Symptoms may develop over weeks to months or it may take years, as the lead gradually accumulates in the body.  Symptoms from exposure to organic lead, which is more toxic than inorganic lead due to its lipid solubility, occur more rapidly.  Symptoms include 

  • Stomach problems - abdominal pain, loss of appetite, nausea
  • Intestine problems - diarrhea or constipation
  • Heart problems – irregular heart beat, shortness of breath, malaise, weakness, tight chest, and high blood pressure.  Lead exposure causes  coronary heart disease, heart rate variability, and has caused death from stroke, it also causes other cardiac autonomic dysfunction
  • Nervous problems - muscle pains, weakness,  pain, or tingling in the extremities, tremor.  It can cause Parkinson disease.  Lead causes the axons of nerve cells to degenerate and lose their myelin coats. There may also therefore be a link with multiple sclerosis
  • Blood and circulatory problems – which may cause fatigue and general tiredness.  It is usually by blood tests that lead poisoning is diagnosed
  • Kidney failure – urination problems, pain in the back.  Lead poisoning also inhibits excretion of the waste product urate and causes a predisposition for gout
  • Autoimmune diseases such as Rheumatism and arthritis – there is a very strong correlation between lead poisoning and arthritis and  rheumatism
  • Reproductive organ problems - Lead affects both the male and female reproductive systems.  In men, sperm count is reduced and changes occur in volume of sperm. There is decreased libido and impotence.   A pregnant woman's elevated blood lead level can lead to miscarriage, prematurity, low birth weight, and problems with development of the baby during childhood. Lead is able to pass through the placenta and into breast milk.  A fetus can be poisoned in utero if lead from the mother's bones is subsequently mobilized by the changes in metabolism due to pregnancy
  • Eye problems – cataracts, loss of sight
  • Mouth problems – lead causes tooth decay and tooth loss.  Lead's effects on the sense of taste may result in astringency and a metallic taste in the mouth.
  • Brain problems - Lead is able to pass through the endothelial cells at the blood brain barrier because it can substitute for calcium ions.  It causes confusion, headache,  irritability, memory loss or impairment, insomnia, and other cognitive deficits. Personality changes can occur.  As the damage proceeds to the brain there can be numerous other symptoms as each organ is attacked. There may be deafness,  paralysis, hallucinations, convulsions, seizures and eventually coma and death.

As a consequence of this, one can then get Behavioural problems [including violent aggressive behaviour] - Lead exposure is correlated with neuropsychiatric disorders such as attention deficit hyperactivity disorder and antisocial behaviour. Elevated lead levels in children [and adults] are correlated with higher scores on aggression and delinquency measures.  A correlation has also been found between lead exposure and violent crime. There also seems to be a link with lead and violent nations.

Countries with the highest air lead levels have been found to have the highest murder rates, after adjusting for confounding factors.  A May 2000 study by economic consultant Rick Nevin theorizes that lead exposure explains 65% to 90% of the variation in violent crime rates in the US. 

  • Cancer- Lead is considered a possible human carcinogen.  There are Pubmed papers that seem to show this
  • Dementia and Alzheimers - age-related mental decline and psychiatric symptoms are correlated with lead exposure.
  • Psychosis - Given that damage  can be to any organ in the brain, it is possible that  some cases of manic depression, schizophrenia, autism and so on – all the diseases related to brain damage  - could have been caused by lead poisoning

 “Mean blood lead concentration was notably higher in 18 autistic children than in 16 nonautistic psychotic children or in ten normal siblings. Fifteen (44%) of the psychotic children (autistic and nonautistic) had blood lead levels greater than two standard deviations above the mean for normal controls”. PMID:  813517

Treatment

Effects of lead on the physiology of the kidneys and blood are generally reversible; its effects on the central nervous system are not.

The only known treatment is chelation therapy.  The chelating agents used for treatment of severe lead poisoning are edetate disodium calcium (CaNa2EDTA), dimercaprol (BAL), which are injected, and succimer and d-penicillamine, which are administered orally.  Chelation therapy only lowers blood lead levels and may not prevent the lead-induced cognitive problems associated with lower lead levels in tissue. Chelating agents can also have adverse effects for example, chelation therapy can lower the body's levels of necessary nutrients like zinc.

Some more suggestions are provided in the observations.

Causes

In the past, the main causes were 

  • Lead pipes - One of the major causes at one time were the lead pipes used to bring water to houses and within houses. Much of this piping in the west has now been replaced with plastic pipe, but this may not be true in other countries.  The problems were known way back in Roman times.  Lead was used extensively in Roman aqueducts from about 500 BC to 300 AD and Julius Caesar's engineer, Vitruvius, reported, "water is much more wholesome from earthenware pipes than from lead pipes. For it seems to be made injurious by lead, because white lead is produced by it, and this is said to be harmful to the human body." 
  • Eating utensils - Another cause in days gone by were the plates, tankards and cups used for eating and drinking which were often made of pewter.  Although Pewter is traditionally 85–99% tin, it can contain lead, in the past it was often in quite high quantities.  As acid and heat can leach lead out into food very easily, this could have been a major cause of lead poisoning in the past [it may still be].  Tinkers often used lead to mend cooking utensils including cooking pots.  Gout, prevalent in affluent Rome, is thought to be the result of lead, or leaded eating and drinking vessels.  It has been noted that Romans also consumed quantities of lead through the consumption of defrutum, carenum, and sapa,  - musts made by boiling down fruit in lead cookware.
  • Patent medicines – medicine was at one time unregulated [herbal medicines still aren’t]  and available not just through chemists but in corner shops. Heinrich Heine may have been a victim of this source, he was certainly suffering in a major way from lead poisoning when he died.
Many secret remedies contained little more than a few vegetable extracts, but others did contain active constituents that might include opium or heavy metals such as mercury, lead, antimony or arsenic which were variously used for treating coughs, colds, consumption,  venereal and skin diseases” [from Making Medicines: A Brief History Of Pharmacy And Pharmaceuticals - Stuart Anderson]

and

 

Shakespeare's tremour and Orwell's cough – Dr John J Ross[many illnesses were the result of] chronic household lead poisoning from adulterated wines, pewter vessels and lead glazed dishes …. unfortunately doctors probably finished things off with lead salts for pneumonia and lead poultices for wounds

  • Lead(II) acetate solution was a commonly used folk remedy for sore nipples. In modern medicine, for a time, it was used as an astringent, in the form of Goulard's Extract. 
  • Wine - Sugar of lead (Lead II Acetate) was once used to sweeten wine, the gout that resulted from this was known as "saturnine" gout.  In 17th-century Germany, the physician Eberhard Gockel discovered lead-contaminated wine to be the cause of an epidemic of colic.  He had noticed that monks who did not drink wine were healthy, while wine drinkers were ill, and traced the cause to sugar of lead, made by simmering litharge with vinegar.  Lead was added to cheap wine illegally in the 18th and early 19th centuries as a sweetener.   The composer Beethoven, a heavy wine drinker, suffered elevated lead levels (as later detected in his hair) possibly due to this; the cause of his death is controversial, but lead poisoning is one factor.   It is supposed to be banned now, but if the Austrians can add antifreeze to wine, who knows what happens.
  • Rum - In 18th century Boston, lead poisoning was fairly frequent on account of the widespread drinking of rum, which was made in stills with a lead component.   Benjamin Franklin suspected lead to be a risk in 1786.  This may seem somewhat trivial until you look at rum consumption at the time.  The first rum distillery was set up in 1664 on present-day Staten Island. Boston, Massachusetts had a distillery three years later. Estimates of rum consumption in the American colonies before the American Revolutionary War had every man, woman, or child drinking an average of 3 imperial gallons of rum each year.  Given the somewhat aggressive nature of the people at this time, lead poisoning may have been a reason.
  • Cider -  Also in the 18th century, "Devonshire colic" was the name given to the symptoms suffered by people of Devon who drank cider made in presses that were lined with lead.
  • Cosmetics - Lead(II) acetate, as well as white lead, have been used in cosmetics throughout history, though this practice has ceased in Western countries. It is still used in men's hair colouring products like Grecian Formula.

  • Artists paints -  I have provided a separate paragraph on this source because it is so important.

These days the causes may be 

  • Lead paint – household paint and the paint used for toys, vehicles and furniture.  In theory lead in paint has been phased out in the west, but it is still allowed in the east especially China.  Since many paints are imported there is thus no guarantee that paints in the west are lead free.
  • Varnishes - Lead(II) acetate is used as a drier in paints and varnishes, and in preparing other lead compounds.
  • Mordant - Lead(II) acetate is also used as a mordant in textile printing and dyeing.
  • Cigarettes – it has been assumed that this is from the contamination of tobacco leaves with lead-containing pesticides.
  • Lead solder – which may be used by plumbers but also found on numerous products.
  • Tin cans - In some countries, the solder in cans used for food contains lead.
  • Water - Lead from the atmosphere or soil can end up in groundwater and surface water. Acidic water breaks down lead in plumbing more readily.  In the US, 14–20% of total lead exposure is attributed to drinking water.  Hot water is more likely than cold water to contain higher amounts of lead. Since most of the lead in household water usually comes from plumbing in the house and not from the local water supply, using cold water helps avoid lead exposure.
  • Fishing weights – which are made of lead
  • Food – residual lead in soil can enter the food chain.  Lead in soil may be caused by broken-down lead paint, residues from lead-containing gasoline, used engine oil, or pesticides used in the past, contaminated landfills, or from nearby industries such as foundries or smelters.  There has been some calls by activists to ban food that is grown near any plants or facilites that may emit lead in fumes or near airports, flight paths and motorways or major road networks.
  • Jewellery – some jewellery believe or not contains lead – sometimes in the
    solder used to make it.
  • Gasoline – which of course at one time contained lead as an additive and in some countries still does; some developing countries still allow leaded gasoline, which is the primary source of lead exposure in most developing countries.  Note that many glue sniffers suffer from lead poisoning.
  • Pesticides -  some pesticides contain lead, in theory they have been phased out in the developed countries but they may still be frequently used in developing countries.
  • Aviation fuel - Tetraethyllead, which was a gasoline additive is still used in fuels such as aviation fuel.
  • Manufacturing  - plants that use lead including recycling plants -   such as is found in facilities that process lead-acid batteries or produce lead wire or pipes, lead smelters and foundries.
    Lead compounds are used in the manufacturing of electronic parts, plastics, rubbers and metals. Lead is used in pigments, dyes, paints and coatings. Lead compounds are used in the manufacture of matches, ammunition, fireworks, explosives, pottery glazes, ceramics, brake shoes, flame retardants for plastics and as catalysts for industrial production and epoxy curing agents.
    Note that the fumes from these plants are as toxic as exposure to the metal within the facilities. In 1656 the German physician Samuel Stockhausen recognized dust and fumes containing lead compounds as the cause of disease, called since ancient Roman times morbi metallici, that were known to afflict miners, smelter workers, potters, and others whose work exposed them to the metal. 
  • Ceramic glaze  - which may contain lead, dishes that have been improperly fired can leach the metal into food, potentially causing severe poisoning.  Thus potters as well as those using pottery are at risk.
  • Waste disposal incinerators – which can emit lead fumes.
  • Kohl - Lead is found in products such as kohl, the cosmetic used in the Middle East, South Asia, and parts of Africa that has many names.
  • Herbal remedies - Lead is commonly incorporated [!] into herbal remedies such as Indian Ayurvedic preparations.  There are also risks of elevated blood lead levels caused by folk remedies like azarcon and greta, which each contain about 95% lead [source Wikipedia].  One Ayurvedic medicine widely used in India and Pakistan called Kushta surb has a lead content as high as 73%!
  • Patent medicines – some Chinese patent medicines have been found to contain heavy metals that include lead and mercury.
  • Ammunition – those who recreationally shoot, for example clay pigeon shooting or grouse, duck and pheasant shooting will be exposed via the lead shot.  If you eat anything which has been shot there is the risk of lead shot poisoning.  Many bullets also contain lead, thus a similar risk exists for those who handle guns that use bullets or who eat animals that have been shot with bullets.  People who have been shot or who have shrapnel wounds run a high risk of exposure.
  • Mining activities - Humans have been mining and using this heavy metal for thousands of years, poisoning themselves in the process.  You can be poisoned by being near a mine, not just working in it.

Other lead-containing products; these include 

  • radiation shields
  • certain surgical equipment may contain lead solder
  • fetal monitors
  • circuit boards may contain lead solder
  • jet engines
  • batteries
  • certain sorts of wire 

Artists’ paints

As early as 1713, Bernardino Ramazzini, the "patron saint" of occupational medicine, described in his classic book, De Morbis Artificum (Diseases of Workers), the hazards of materials to which painters are exposed. He wrote:

I have observed that nearly all the painters whom I know, both in this and other cities, are sickly; and if one reads the lives of painters it will be seen that they are by no means long-lived, especially those who were the most distinguished

Some artists pigments are lead based and contain high quantites of lead.  It was probably worse in olden days  if you mixed your own paints, as the dust could be more easily inhaled or absorbed via the skin.  The painter Caravaggio is said to have died of lead poisoning. Caravaggio is known to have indulged in violent behavior, a symptom of lead poisoning.

In art, white lead paint is known as "flake white" or "Cremnitz white". It is valued for the ease of handling and resilience the lead confers to oil paints. Lead-based white is one of the oldest manufactured pigments and is used in the manufacture of a number of other pigments.   Chrome Yellow is also a natural yellow pigment made of lead(II) chromate (PbCrO4).

Other lead pigments include cremnitz white, Naples yellow and red lead.  There is a separate section dealing with mercury poisoning, but it is worth adding here I think that the pigment Vermilion is a toxic mercury compound favored for its deep red-orange color by many old master painters such as Titian.

I think we underestimate the effect lead and mercury poisoning probably had on artists in the past.

Many of the most famous artists working in France late in the 19th century suffered serious eye diseases. - Monet, Cassatt, Degas, and Pissarro being just four. 

The painters Rubens, Renoir, and Dufy suffered from rheumatoid arthritis and Klee from scleroderma. Analysis of the areas of various colours in randomly selected paintings by these four artists and by eight "controls" (contemporary painters without rheumatic disease) suggests that Rubens, Renoir, Dufy, and Klee used significantly more bright and clear colours based on toxic heavy metals and fewer earth colours containing harmless iron and carbon compounds. These four painters may have been heavily exposed to mercury sulphide, cadmium sulphide, arsenic sulphide, lead, antimony, tin, cobalt, manganese, and chromium, the metals of the bright and clear colours, and exposure to these metals may be of importance in the development of inflammatory rheumatic diseases. Artists today are not so exposed, but heavy metal contamination in food and drinking water exists and experience from the occupational exposure of old masters is still relevant” [source Rheumatic disease, heavy-metal pigments, and the Great Masters - Pedersen LM, Permin H  - Department of Infectious Diseases, Rigshospitalet, Copenhagen, Denmark. PMID: 2897527]

How it works

Poisoning and brain damage

The picture to the right from Wikipedia shows areas of damage in brains exposed to lead. 

As you can see the areas affected can vary considerably – any number of different areas can be affected which means that the effects will vary from person to person

The brains of adults who were exposed to lead as children show decreased volume, especially in the prefrontal cortex, on MRI. Areas of volume loss are shown in color over a template of a normal brain”

References and further reading

There are numerous papers on PubMed which show the effects and continued prevalence of lead poisoning  - literally thousands and thousands.  Furthermore many of them show how even today the sources of lead poisoning are not understood, for example:

  • Lead poisoning--a case report -   Amundsen T, Naess IA, Hammerstrøm J, Brudevold R, Bjerve KS.  Medisinsk klinikk, St. Olavs Hospital, 7006 Trondheim. tore.amundsen@medisin.ntnu.no
  • A wine pitcher, cause of lead poisoning -  Jouglard J, de Haro L, Arditti J, Cottin C.  Centre Anti-Poisons, Hôpital Salvator, Marseille  “This case of lead poisoning caused by a single earthenware wine jug confirms the need for rigorous governmental directives to control the production and distribution of varnished earthenware”  PMID: 8729326

Related observations