World Health Organization: On lead poisoning and health problems

Lee Jeong-woo

Abstract: On August 23, 2019, the World Health Organization published an article on its official website "Lead Poisoning and Health", which discusses the sources and routes of exposure of lead, the health effects of lead poisoning on children, the burden of disease caused by lead exposure, and the response measures taken by the World Health Organization, which is worth reading.

It is reproduced below through today's headline personal public account "Li On Chemical Management" for the research and reference of readers from all walks of life.

Important facts

· Lead is a cumulative poison that affects multiple systems of the body and is especially harmful to young children.

· Lead in the body is distributed in the brain, liver, kidneys and bones. Lead is stored in teeth and bones and accumulates over time. Human exposure is usually assessed by measuring lead in the blood.

· Lead in bones is released into the bloodstream during pregnancy, forming a source of exposure to the developing fetus.

· There are no levels of lead exposure that are known not to cause harmful effects.

· Lead exposure is preventable.

preface

Lead is a toxic metal that occurs naturally in the Earth's crust. In many parts of the world, the widespread use of lead has caused widespread environmental pollution, human exposure and significant public health problems.

Important sources of environmental pollution include mining, smelting, production and recycling activities, as well as the continued use of lead paint and leaded gasoline in some countries. More than three-quarters of the world's lead consumption is used to manufacture lead-acid batteries in motor vehicles.

However, lead is also used in many other products, such as pigments, paints, welds, stained glass, lead crystal glassware, ammunition, ceramic glazes, jewelry, toys and certain cosmetics and traditional medicines.

Drinking water transported through lead pipes or pipes connected with leaded solder may contain lead. Much of the lead sold commercially worldwide is now obtained through recycling methods.

Young children are particularly vulnerable to the toxic effects of lead and have to endure severe and permanent harmful health effects, particularly affecting the development of the brain and nervous system.

Lead can also cause long-term damage in adults, including an increased risk of high blood pressure and kidney damage. Exposure of pregnant women to high concentrations of lead can lead to miscarriage, stillbirth, preterm birth and low birth weight.

1. Source and route of exposure

People may be exposed to lead through occupational and environmental sources. This is mainly due to:

inhalation of lead particulate matter resulting from the combustion of lead-containing materials, for example, in lead smelting, recycling, stripping of leaded paint and the use of leaded gasoline or leaded aviation fuel;

- Ingestion of lead-contaminated dust, water (delivered by leaded pipes) and food (from lead glazed or lead-welded containers).

Another source of exposure is the use of certain uncontrolled cosmetics and drugs. For example, some kohl cosmetics and some traditional medicines used in countries such as India, Mexico and Vietnam have been reported to have higher concentrations of lead.

Therefore, consumers should be careful to buy and use only regulated products.

Young children are particularly vulnerable to lead poisoning because they absorb 4 to 5 times as much lead from specific sources as adults.

Moreover, children's innate curiosity and age-appropriate hand-sucking behavior lead them to put leaded or lead-plated items in their mouths or swallow, for example, contaminated soil or dust and shed lead paint debris.

This route of exposure has a greater impact on children with pica psychological disorder (always compulsive desire to eat non-food items). For example, they may remove lead paint from walls, door frames, and furniture and eat it.

Among young children in Senegal and Nigeria, exposure to lead-contaminated soil and dust from battery recycling and mining has resulted in high levels of lead poisoning and multiple deaths.

Once lead enters the body, it is distributed to organs such as the brain, kidneys, liver and bones. Lead is stored in teeth and bones and accumulates over time. Lead stored in bones may re-enter the bloodstream during pregnancy, exposing the fetus to contact.

Undernourished children are more susceptible to the effects of lead because when other nutrients such as calcium or iron are lacking, the body absorbs more lead. The children at highest risk are young children (including developing fetuses) and children with poor economic conditions.

2. The health effects of lead poisoning on children

Lead exposure can have a serious impact on children's health. When exposed to high concentrations, lead can affect the brain and central nervous system, causing coma, convulsions, and even death. Children recovering from severe lead poisoning may have problems with mental retardation and behavioral disorders.

When exposure to low concentrations of lead does not cause significant symptoms, it is currently known to cause a range of injuries in multiple systems of the body. In particular, lead can affect children's brain development, causing a decline in IQ, behavioral changes such as shortened attention span and increased antisocial behavior and decreased academic performance.

Lead exposure can also cause anemia, hypertension, impaired renal function, immunotoxicity, and reproductive organ toxicity. The neurological and behavioral effects of lead are thought to be irreversible.

There are no known "safe" blood lead concentrations; even if blood lead concentrations as low as 5 μg/dL, it may be associated with mental decline, behavioral difficulties, and learning problems in children. As lead exposure levels rise, so does the scope and severity of symptoms and effects.

Encouragingly, leaded gasoline has been successfully phased out in most countries, and other lead control measures have led to a significant decline in population blood lead concentrations. Only one country continues to use leaded fuel (1).

However, much remains to be done to phase out lead paint. So far, only 37% of countries have legally binding controls on lead paint (2).

3. Disease burden caused by lead exposure

The Institute for Health Metrics and Evaluation (IHME) estimates that 1.06 million people died and 24.4 million disability-adjusted life years were lost globally in 2017 due to the long-term health effects of lead exposure. Low- and middle-income countries face the heaviest burden.

The institute also estimates that lead exposure accounts for 63.2% of the global burden of idiopathic intellectual disability, 10.3% of the global burden of hypertensive heart disease, 5.6% of ischemic heart disease, and 6.2% of the burden of stroke (3).

4. The World Health Organization's response

The World Health Organization has identified lead as one of ten chemicals of major public health concern, requiring action by Member States to protect the health of workers, children and women of childbearing age.

The World Health Organization has a range of information on lead on its website, including information for policymakers, technical guidance, and advocacy materials.

The World Health Organization is currently developing guidelines on the prevention and management of lead poisoning. The guidelines will provide policymakers, public health authorities, and health professionals with evidence-based guidance on the measures they can take to prevent lead exposure and protect the health of children and adults.

Because lead paint remains a source of exposure to lead in many countries, the World Health Organization and the United Nations Environment Programme have formed the Global Alliance to Eliminate Lead Paint.

This collaborative initiative focuses on and strives to contribute to the international goal of preventing children from being exposed to lead in lead paint and minimizing occupational exposure to such paint.

The broad objective of the Alliance is to promote the phasing out of the production and sale of lead paints and, ultimately, to eliminate the risks posed by such coatings.

The Global Alliance for the Elimination of Lead Paint is an important tool for promoting the implementation of paragraph 57 of the Plan of Implementation of the World Summit on Sustainable Development and resolution II/4 B of the Strategic Approach to International Chemicals Management (SAICM), both of which focus on the phase-out of lead paint.

WHO is also a partner in a GEF-funded project to support legally binding controls on lead paint in at least 40 countries (4).

Phasing out lead paint by 2020 is one of the priority actions called for by Governments in the WORLD's Roadmap for Enhancing Health Sector Participation in the Strategic Approach to International Chemicals Management in The Pursuit of 2020 and Beyond.

This roadmap was endorsed in decision WHA70(23) of the 70th World Health Assembly.

Eliminating lead paint will contribute to the achievement of the following sustainable development goals:

3.9: By 2030, significantly reduce the number of deaths and illnesses from hazardous chemicals and air, water and soil pollution.

- 12.4: By 2020, in accordance with the agreed international framework, achieve the environmentally sound management of chemicals and all wastes throughout their life cycle and significantly reduce their release into the atmosphere, water bodies and soils in order to minimize their negative impact on human health and the environment.

bibliography

(1) Leaded Petrol Phase-out globally (2019), Nairobi: United Nations Environment Programme; 2019.

(2) Global Health Observatory: Regulations and controls on lead paint, Geneva: World Health Organization; 2019

(3) Institute for Health Metrics and Evaluation (IHME). GBD Compare. Seattle, WA: IHME, University of Washington; 2017.

(4) SAICM GEF Project - Lead in Paint Component.

Source: World Health Organization. Lead Poisoning and Health, [2020-9-11], https://www.who.int/zh/news-room/fact-sheets/detail/lead-poisoning-and-health