Essential Minor Elements are of:
Cl, P, Na, K, Mg, Ca
Essential Trace Elements are of:
Fe, F, Zn, I, Cu, Cr, Co, Mn, Mo, Se
New Essential Elements are of:
V, Sn, Al, Ni
Toxic Essential Elements are of:
Pb, Cd, Hg As
Radiological Trace Elements:
I , Cs, Sr, k,
Important factors Regarding the Trace Elements are of:
Phytate
Fiber
Energy
Vitamins and many other factors
Important Web sites, Societies, Journals, Research Centers and ..
regarding the Trace Elements:
Metals
All substances are composed of only about a hundred fundamental
kinds of matter called elements. Each element is made up of very
small entities called atoms ; all atoms of the same element behave
identically chemically.
Each element is designated by an atomic number, a name, and a
chemical symbol such as carbon, C, zinc, Zn.
Each element has a characteristic atomic mass which is the average
mass of all atoms of the element. The atomic number is a unique,
important way of designating each element, and it is equal to the
number of protons in the nuclei of each atom of the element.
Metals, nonmetals and metalloids :
Metals are elements that are generally solid, shiny in appearance,
electrically conducting, and malleable. They tend to have only 1-3
outer electrons which they may lose in forming chemical compounds.
Examples of metals are iron, copper, silver.
Nonmetals often have a dull appearance, are not at all malleable,
and frequently occur as gases or liquid. Colorless oxygen gas, green
chlorine gas and brown bromine liquid are common non metals.
Nonmetals tend to have close to a full octet of outer-shell
electrons, and in forming chemical compounds, they gain or share
electrons.
Metalloids, such as silicon or arsenic, are elements with properties
intermediate between those of metals and nonmetals – under some
conditions a metalloid may exhibit properties of metals, and under
other conditions, properties of non metals.
Conventionally, trace elements are elements which are present in low
quantities in the earth, plants, animals and man.
Man is dependent on an ecosystem (the food chain) which provides him
with trace elements. This ecosystem is the result of an equilibrium
in constant movement.
Trace elements are elements present at levels of under 1 mg/kg of
body weight
Trace elements in the human body in g/kg
Iron ......................... 0.06
Fluorine ................... 0.037
Zinc ....................... ..0.033
Rubidium ................. 0.0046
Strontium ............... ..0.0046
Bromine .................. .0.0029
Copper .....................0.001
Vanadium ................ 0.0003
Selenium ................. 0.0002
Manganese ............. 0.0002
Iodine .......................0.0002
Molybdenum ............ 0.0001
Nickel ....................... 0.0001
Chromium ..................0.00002
Cobalt .................... ..0.00002
Uranium ................... 0.000001
Beryllium .................. 0.0000003
The 68 trace elements present in the Earth’s crust each have a
concentration of less than 0.1 %, for instance :
Fluorine ..................... 700 mg/kg
Chlorine .................... 200 mg/kg
Chromium ..................200 mg/kg
Vanadium ............... .110 mg/kg
Nickel ..................... ....80 mg/kg
Zinc ............................ 65 mg/kg
Nitrogen ..................... 46 mg/kg
Copper .................... ...45 mg/kg
Cobalt .................... ....23 mg/kg
Lead .................... ......15 mg/kg
Boron ...................... ....3 mg/kg
Molybdenum ............... 1 mg/kg
Iodine ...................... ...0.3 mg/kg
Cadmium .................... 0.2 mg/kg
Selenium .................... 0.09 mg/kg
Essential trace elements are those that respond to three criteria :
•They are present in living tissues at a relatively constant
concentration
•They provoke similar structural and physiological anomalies in
several species when removed from the organism
•These anomalies are prevented or cured by supplementation with a
single element
The essential trace elements recognized by the WHO (1997) are
Iodine, Zinc, Selenium, Copper, Molybdenum, Chromium but others are
probably essential, such as Manganese, Nickel, Vanadium etc
Increasingly sensitive analytical techniques will probably show that
there are other essential trace elements.
Understanding the impact of trace elements on metabolic processes is
an area for fundamental research and implies multidisciplinary
studies in the fields of biochemistry, pharmacology, toxicology,
genetics, epidemiology, therapeutics and also agronomy and
veterinary sciences. |
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