Heavy metals

Although the term “heavy metal” is commonly used, there is no standard definition assigning metals as heavy metals. However, the term usually refers to any metallic chemical element that has a relatively high density and is toxic or poisonous at low concentrations.

Some lighter metals and metalloids are toxic and, thus, are termed heavy metals though some heavy metals, such as gold, typically are not toxic.

Most of those have a high atomic number, atomic weight and a specific gravity greater than 5.0 Heavy metals include some metalloids, transition metals, basic metals, lanthanides, and actinides. Although some metals meet certain criteria and not others.

Heavy metals can be both natural and synthetic elements, as well as elements that are heavy, but necessary for animal and plant nutrition.

Examples of those include lead, mercury, cadmium, and sometimes chromium.

Less commonly, metals including iron, copper, zinc, aluminium, beryllium, cobalt, manganese, and arsenic may be considered heavy metals.


Below, you can find some of the most relevant articles regarding this topic:


This article can be found in the 2022 edition of the document. Find the full publication here:

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