Métaux lourds : quel impact sur notre santé ?

Heavy metals: what impact on our health?

Feb 20, 2024

Heavy metals are inherent to the environment, occurring naturally in soil, water and air. However, human activity has significantly increased their presence and is responsible for their accumulation. Chemical elements such as lead, mercury, cadmium, arsenic and nickel are known to be toxic. What are the real effects of these substances? And how can we reduce our exposure to these potentially harmful agents?

Where are heavy metals found?

Heavy metals are metallic elements that occur naturally in the environment . They are also found in other environments such as industry, agriculture, waste, fossil fuels and everyday consumer products. Generally emitted in the form of fine particles, they are dispersed in soil and aquatic environments via the wind, thus contaminating flora, fauna and the food chain. Among the most widespread heavy metals, we find:

  • Lead , present in particular in the paint of old buildings, batteries, fuses, ceramics, etc. It is one of the main toxic contaminants in the environment.
  • Mercury , used in products such as thermometers and fluorescent light bulbs.
  • Cadmium , rarely found alone in nature, is associated with other metals in ores and can be released into the environment by various industrial processes. It is used, for example, in the manufacture of rechargeable batteries, plastic, dyes, etc. It is also present in phosphate fertilizers and tobacco.
  • Arsenic, present in some regions in high concentrations, can be emitted by natural activities such as the erosion of rocks or human activities such as the burning of fossils. It is mainly found in water and food.

These heavy metals can enter the body through inhalation, ingestion or skin exposure. Exposure by inhalation mainly affects professionals and populations living near certain industrial sites.

What effects on health?

The impact of heavy metals on human health depends on various factors such as their chemical composition, concentration, bioavailability and integration into food webs. However, it is not uncommon for exposure to these metals to have devastating health consequences.

This is why they are subject to rigorous monitoring in France because of the risks they represent, as evidenced by their classification by the IARC. For example, cadmium and its compounds are classified as a Group 1 carcinogen, inorganic lead as a Group 2A probable carcinogen, and methylmercury as a Group 2B possible carcinogen.

Additionally, some of these metals, such as cadmium , have no essential biological value , while others that are necessary can become toxic at high concentration levels.

Impact of the most common heavy metals

The effects of heavy metals on human health can be significant . For example, exposure to cadmium (especially orally in high doses) can lead to severe gastrointestinal irritation and kidney damage. Chronic exposure by inhalation is associated with pulmonary and kidney problems, and even bone lesions.

Lead , once in the body, concentrates in the blood and then attaches to soft tissues. Its major impact is felt on the central nervous system, particularly in fetuses and young children, leading to brain damage, developmental delays and behavioral disorders.

Mercury , classified by the WHO as a chemical of major public health concern, mainly affects the kidneys and can cause balance disorders, hearing and visual problems, as well as psychomotor and growth delays. in children (while being fetotoxic).

Arsenic , with its multiple toxic properties such as uncoupling of the respiratory chain, action as an endocrine disruptor and disruption of cellular differentiation, presents carcinogenic risks. Finally, nickel can trigger allergic skin reactions and respiratory problems.

How to reduce your exposure?

To preserve your health, it is therefore essential to put in place measures to limit exposure to heavy metals. Initially, it seems wise to limit or even ban the use of products containing these metals , such as lead paints and consumer products containing mercury.

It is also important to avoid tobacco smoke , which contains cadmium, and to maintain a balanced and varied diet by avoiding potentially contaminated foods such as seafood high in mercury.

Filtering drinking water and regularly monitoring its quality is also recommended. Additionally, maintaining rigorous hygiene by regularly cleaning surfaces can prevent the buildup of dust that may contain lead.

The importance of detoxification

Detoxification , often called "detox", refers to the process by which the body rids itself of harmful and unwanted substances . This process is of great importance as it effectively neutralizes and removes toxins such as heavy metals, helping to maintain overall health.

To achieve this goal, various plants can be used . Indeed, scientific research has made it possible to identify the benefits of some of them. This is particularly the case for spirulina , pilosella , and even black radish.

Other strategies, such as favoring nutrient-rich foods and maintaining adequate hydration by drinking enough water, may also be beneficial. Indeed, these habits contribute to the proper functioning of the organs involved in the detoxification process.

In short, heavy metals mainly pose a threat to human health due to their toxicity and their widespread presence in the environment. It is therefore crucial to adopt measures to reduce exposure to these harmful substances. And, despite the multiplication of government initiatives to reduce this exposure, it remains a current challenge.

References :

Our-environment.gov. (Updated July 11, 2019). Heavy metals: cadmium, mercury and lead.

Ministry of Labor, Health and Solidarity. (April 1 , 2015). Sources of lead exposure.

Environmental health association France. (June 6, 2017). Heavy metals: the ASEF synthesis.

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