Reposted from WHO website: https://www.who.int/news-room/fact-sheets/detail/lead-poisoning-and-health

Claytan Lead Safe

Key facts

  • Lead is a cumulative toxicant that affects multiple body systems and is particularly harmful to young children.
  • 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.
  • Lead in bone is released into blood during pregnancy and becomes a source of exposure to the developing fetus.
  • There is no level of exposure to lead that is known to be without harmful effects.
  • Lead exposure is preventable.

Overview

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.

Important sources of environmental contamination come from mining, smelting, manufacturing and recycling activities and use in a wide range of products. 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, lead crystal glassware, ammunition, ceramic glazes, jewellery, toys, some cosmetics such as kohl and sindoor, and traditional medicines used in countries such as India, Mexico and Viet Nam. Drinking water delivered through lead pipes or pipes joined with lead solder may contain lead. Much of the lead in global commerce is now obtained from recycling.

Young children are particularly vulnerable to the toxic effects of lead and can suffer profound and permanent adverse health impacts, particularly on 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.

Sources And Routes Of Exposure

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

  • inhalation of lead particles generated by burning materials containing lead, for example during smelting, recycling, stripping leaded paint and using leaded aviation fuel; and
  • ingestion of lead-contaminated dust, water (from leaded pipes) and food (from lead-glazed or lead-soldered containers).

Young children are particularly vulnerable to lead poisoning 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 lead-coated objects, such as contaminated soil or dust and flakes from decaying lead-containing paint. This route of exposure is magnified in children with a psychological disorder called pica (persistent and compulsive cravings to eat non-food items), who may pick away at and eat leaded paint from walls, door frames and furniture. Exposure to lead-contaminated soil and dust resulting from battery recycling and mining has caused mass lead poisoning and multiple deaths in young children in Nigeria, Senegal and other countries.

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 released into the blood during pregnancy, thus exposing the fetus. Undernourished children are more susceptible to lead because their bodies absorb more lead if other nutrients, such as calcium or iron, are lacking. Children at highest risk are the very young (including the developing fetus) and the economically disadvantaged.

Health Effects In Children

Lead exposure can have serious consequences for the health of children. At high levels of exposure lead attacks the brain and central nervous system, causing coma, convulsions and even death. Children who survive severe lead poisoning may be left with intellectual disability and behavioural disorders. At lower levels of exposure that cause no obvious symptoms, lead is now known to produce a spectrum of injury across multiple body systems. In particular, lead can affect children’s brain development, resulting in reduced intelligence quotient (IQ), behavioural changes such as reduced 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.

There is no known safe blood lead concentration; even blood lead concentrations as low as 3.5 µg/dL may be associated with decreased intelligence in children, behavioural difficulties and learning problems (1). As lead exposure increases, the range and severity of symptoms and effects also increase.

Encouragingly, the successful phasing out of leaded gasoline in most countries, together with other lead control measures, has resulted in a significant decline in population-level blood lead concentrations. As of July 2021, leaded fuel for cars and lorries is no longer sold anywhere in the world (2). However, more needs to be done to phase out lead paint; so far, only 45% of countries have introduced legally binding controls on lead paint.

Burden Of Disease

The World Health Organization’s 2021 update of the Public health impact of chemicals: knowns and unknowns estimate that nearly half of the 2 million lives lost to known chemicals exposure in 2019 were due to lead exposure. Lead exposure is estimated to accounts for 21.7 million years lost to disability and death (disability-adjusted life years, or DALYs) worldwide due to long-term effects on health, with 30% of the global burden of idiopathic intellectual disability, 4.6% of the global burden of cardiovascular disease and 3% of the global burden of chronic kidney diseases.

WHO Response

WHO has identified lead as one of 10 chemicals of major public health concern needing action by Member States to protect the health of workers, children and women of reproductive age. WHO has made available through its website a range of information on lead, including information for policy-makers, technical guidance and advocacy materials. WHO has developed guidelines on clinical management of lead exposure and is preparing guidelines on prevention of lead exposure, which will provide policy-makers, public health authorities and health professionals with evidence-based guidance on the measures that they can take to protect the health of children and adults from lead exposure.

Since leaded paint is a continuing source of exposure in many countries, WHO has joined with the United Nations Environment Programme to form the Global Alliance to Eliminate Lead Paint. WHO is also a partner in a project funded by the Global Environment Facility that aims to support at least 40 countries in enacting legally binding controls on lead paint (3). The phasing out of lead paint by 2020 is one of the priority actions for governments included in the WHO Road map to enhance health sector engagement in the Strategic Approach to International Chemicals Management towards the 2020 goal and beyond.

References

(1) US CDC Advisory Committee on Childhood Lead Poisoning Prevention. CDC updates blood lead reference value to 3.5µg/dL. Atlanta: US Centres for Disease Control and Prevention; 2021 (https://www.cdc.gov/nceh/lead/news/cdc-updates-blood-lead-reference-value.html).

(2) End of leaded fuel use a “milestone for multilateralism” press release https://news.un.org/en/story/2021/08/1098792, 2021.

(3) SAICM GEF Project – Lead in Paint Component




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