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Heavy metals is a controversial and ambiguous term [2] for metallic elements with relatively high densities, atomic weights, or atomic numbers.The criteria used, and whether metalloids are included, vary depending on the author and context and it has been argued that the term "heavy metal" should be avoided.
A toxic heavy metal is a common but misleading term for a metal-like element noted for its potential toxicity. [4] Not all heavy metals are toxic and some toxic metals are not heavy. [ 5 ] Elements often discussed as toxic include cadmium , mercury and lead , [ 6 ] all of which appear in the World Health Organization 's list of 10 chemicals of ...
Many metals, particularly heavy metals are toxic, but some are essential, and some, such as bismuth, have a low toxicity. Metals in an oxidation state abnormal to the body may also become toxic: chromium(III) is an essential trace element, but chromium(VI) is a carcinogen. Only soluble metal-containing compounds are toxic.
The rare-earth elements (REE), also called the rare-earth metals or rare earths, and sometimes the lanthanides or lanthanoids (although scandium and yttrium, which do not belong to this series, are usually included as rare earths), [1] are a set of 17 nearly indistinguishable lustrous silvery-white soft heavy metals. Compounds containing rare ...
Like the periodic table, the list below organizes the elements by the number of protons in their atoms; it can also be organized by other properties, such as atomic weight, density, and electronegativity. For more detailed information about the origins of element names, see List of chemical element name etymologies.
A number of pigments, especially traditional ones, contain heavy metals such as lead, mercury, and cadmium that are highly toxic. The use of these pigments is now highly restricted in many countries. [1]
Arsenic is a notoriously toxic heavy metal. It occurs naturally in many minerals , usually in combination with sulfur and metals, but also as a pure elemental crystal . It has various allotropes , but only the grey form, which has a metallic appearance, is important to industry.
May acidify its own rhizosphere, which would facilitate absorption by solubilization of the metal [31] [1]: 19, 891, 898 [32] [33] [34] [42] Zn: Trifolium pratense: Red Clover: Nonmetal accumulator. Its rhizosphere is denser in bacteria than that of Thlaspi caerulescens, but T. caerulescens has relatively more metal-resistant bacteria. [31]