In July 2021, the use of leaded gasoline was discontinued worldwide
As of July 2021, leaded fuel for cars and trucks will no longer be sold anywhere in the world. The global phase-out of leaded fuels is a "milestone in multilateralism" and marks the end of a 20-year campaign to eliminate major threats to human and the health of the planet.
However, more needs to be done to phase out lead paint. As of August 31, 2021, 43% of countries have confirmed legally binding controls over the production, import, sale and use of lead paint.
First, where does lead come from?
Lead is a toxic heavy metal that occurs naturally in the Earth's crust.
Lead comes from a wide range of sources, including:
1. Mining, smelting, manufacturing and recycling activities;
2. Some countries continue to use lead paint and leaded aviation fuel;
3. Manufacture of lead-acid batteries for automobiles;
4. Other products, such as pigments, paints, solders, stained glass, lead crystal glassware, ammunition, ceramic glazes, jewelry, toys and some cosmetics and traditional medicines.
Second, the toxicity of lead
Lead is a cumulative toxic substance that affects multiple systems of the body, including the nervous system, blood system, gastrointestinal system, cardiovascular system, immune system, and kidney system.
Stored in teeth and bones, it accumulates there over time.
Lead in bones is released into the bloodstream during pregnancy and becomes a source of exposure for developing fetuses, leading to miscarriages, stillbirths, preterm births and birth weight.
Children are particularly vulnerable to the neurotoxic effects of lead, and even relatively low levels of exposure can cause severe or irreversible nerve damage, leading to decreased IQ, inattention, increased antisocial behavior, and reduced educational attainment; The effects of lead on nerves and behavior are considered irreversible.
Malnourished children are more susceptible to the effects of lead, and the body absorbs more lead due to a lack of other nutrients such as calcium or iron.
The World Health Organization, in its 2021 update of The Public Health Impacts of Chemicals: Known and Unknown, estimates that nearly half of the 2 million people who died from exposure to known chemicals in 2019 were due to exposure to lead and the resulting cardiovascular disease, with the burden highest in low- and middle-income countries.
Third, lead is absorbed, distributed and excreted in the body
1. Absorption
(1) Mainly in the form of lead vapor, lead dust, lead smoke through the respiratory tract into the human body; a small amount of lead dust can adhere to the mouth, throat mucosa wall and be swallowed.
(2) Drinking water, smoking or ingesting lead-contaminated food enters the human body through the digestive tract.
(3) The organic compounds of lead can be absorbed through the skin.
2. Distribution
More than 90% of lead binds to erythrocytes, part of it binds to plasma proteins, a small amount forms soluble lead hydrogen phosphate, and the lead in the blood is distributed with blood circulation in blood-rich organs. After a few weeks, it is transferred from soft tissue to bones, hairs, teeth, etc., and deposited in the form of refractory lead phosphate.
90%-95% of the lead of the human body is stored in the bones, when the lack of calcium in food or acid-base imbalance, can make the insoluble lead phosphate in the bone into soluble lead hydrogen phosphate into the blood, causing lead poisoning.
3. Excretion
It is excreted mainly through the kidneys with urine, but also with feces, lotion, saliva, sweat and menstruation, and can also enter the baby through the placenta.
bibliography:
(1) The global cessation of leaded fuels is a "milestone in multilateralism", press release
https://news.un.org/zh/story/2021/08/1090282，2021.
(2) Global Health Observatory: Regulations and control measures for lead paint
Geneva: World Health Organization; 2021.
(3) Institute for Health Metrics and Evaluation (IHME). GBD Compare.
Seattle, WA: IHME, University of Washington; 2019.
(4) SAICM GEF Project - Lead in Paint Component