Toxic metal

Toxic metal

Toxic metals are metals that form poisonous soluble compounds and have no biological role, i.e. are not essential minerals, or are in the wrong form[1]. Often heavy metals are thought as synonymous, but lighter metals also have toxicity, such as beryllium, and not all heavy metals are particularly toxic, and some are essential, such as iron. The definition may also include trace elements when considered in abnormally high, toxic doses. A difference is that there is no beneficial dose for a toxic metal with no biological role.

Toxic metals sometimes imitate the action of an essential element in the body, interfering with the metabolic process to cause illness. Many metals, particularly heavy metals are toxic, but some heavy metals are essential, have a low toxicity, and bismuth is non-toxic. Most often the definition includes at least cadmium, lead, mercury and the radioactive metals.[citation needed] Metalloids (arsenic, polonium) may be included in the definition. Radioactive metals have both radiological toxicity and chemical 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.

Toxicity is a function of solubility. Insoluble compounds as well as the metallic forms often exhibit negligible toxicity. The toxicity of any metal depends on its ligands. In some cases, organometallic forms, such as dimethyl mercury and tetraethyl lead, can be extremely toxic. In other cases, organometallic derivatives are less toxic such as the cobaltocenium cation.

Decontamination for toxic metals is different from organic toxins: because toxic metals are elements, they cannot be destroyed. Toxic metals may be made insoluble or collected, possibly by the aid of chelating agents.

Toxic metals can bioaccumulate in the body and in the food chain. Therefore, a common characteristic of toxic metals is the chronic nature of their toxicity. This is particularly notable with radioactive heavy metals such as thorium, which imitates calcium to the point of being incorporated into human bone, although similar health implications are found in lead or mercury poisoning. The exceptions to this are barium and aluminium, which can be removed efficiently by the kidneys.

Contents

Toxic metals

Aluminium has no biological role and its classification into toxic metals is controversial. Significant toxic effects and accumulation to tissues have been observed in renally impaired patients.[2] However, individuals with healthy kidneys can be exposed to large amounts of aluminium with no ill effects. Thus, aluminium is not considered dangerous to persons with normal elimination capacity.[3]

Trace elements with toxicity

Nonmetals

Some heavy nonmetals may be erroneously called "metals", because they have some metallic properties.

See also

References

  1. ^ Dartmouth Toxic Metal Research - Toxic Metals!
  2. ^ Acute Aluminum Neurotoxicity Secondary To Treatment Of Severe Hyperphosphatemia Of Acute Renal Failure And The K/DOQI Guidelines
  3. ^ eMedicine - Toxicity, Aluminum : Article by Michael R Edwards

External links



Wikimedia Foundation. 2010.

Игры ⚽ Нужен реферат?

Look at other dictionaries:

  • Metal fume fever — Classification and external resources ICD 10 T59.9 ICD 9 987.8 Metal fume fever also known as brass founders ague, brass shakes …   Wikipedia

  • Metal-organic framework — Metal Organic Frameworks are crystalline compounds consisting of metal ions or clusters coordinated to often rigid organic molecules to form one , two , or three dimensional structures that can be porous. In some cases, the pores are stable to… …   Wikipedia

  • Toxic Holocaust — Allgemeine Informationen Genre(s) Thrash Metal (mit Black Metal Einflüssen), Speed Metal Gründung 1999 Website …   Deutsch Wikipedia

  • Toxic Smile — Allgemeine Informationen Genre(s) Progressive Metal Gründung 1996 Website www.toxic smile.de …   Deutsch Wikipedia

  • Toxic Holocaust — Infobox musical artist Name = Toxic Holocaust Img capt = Img size = Background = group or band Origin = Maryland, USA Genre = Thrash metal Black metal Years active = 1999–present Label = Relapse Records Associated acts = Tiger Junkies Colon… …   Wikipedia

  • Metal carbonyl — Iron pentacarbonyl An iron atom with five CO ligands Metal carbonyls are coordination complexes of transition metals with carbon monoxide ligands. These complexes may be homoleptic, that is containing only CO ligands, such as nickel carbonyl… …   Wikipedia

  • Metal clay — Pendant made from metal clay with gold powder Metal clay is a crafting medium consisting of very small particles of metal such as silver, gold, platinum, or copper mixed with an organic binder and water for use in making jewelry, beads and small… …   Wikipedia

  • Metal foam — Foamed aluminium A metal foam is a cellular structure consisting of a solid metal, frequently aluminium, containing a large volume fraction of gas filled pores. The pores can be sealed (closed cell foam), or they can form an interconnected… …   Wikipedia

  • toxic — adj. VERBS ▪ be, prove, stay ▪ Black walnuts can prove toxic to other plants. ▪ become ▪ remain ADVERB …   Collocations dictionary

  • toxic — tox|ic [ˈtɔksık US ˈta:k ] adj [Date: 1600 1700; : Late Latin; Origin: toxicus, from Latin toxicum poison , from Greek toxikon arrow poison , from toxon bow, arrow ] containing poison, or caused by poisonous substances ▪ fumes from a toxic waste… …   Dictionary of contemporary English

Share the article and excerpts

Direct link
Do a right-click on the link above
and select “Copy Link”