Emphasis on Elements prepared by
J. Chem. Educ. Staff Chem I Supplement is a new monthly feature planned to give teachers of first courses in chemistry additional chemical information that might he used in class, posted on bulletin boards, or used to stimulate additional student involvement in activities related to chemistry. 25 and 50 ppm: iron*, silicon (variable),zinc* 1 and 10 ppm: rubidium, copper*, strontium, bromine, tin, manganese*, iodine* 0.2 and 0.5 ppm: aluminum, lead, barium, molybdenum*, boron 2 X 10-2 and 4 X 10-2ppm: arsenic, cobalt*,chromium, lithium, vanadium, nickel less than 2 X 10W: cadmium. selenium.
Major Metals and Minerals Major metals and minerals used by all countries can be classified as follows 1) Iron ore
2) Base metals: Copper, Lead, Tin, Zinc 3) Precious metals: Gold, Platinum, Silver 4) Light metals: Aluminum,
Magnesium, Titanium
5) Ferroalloy metals: Chromium, Manganese, Molybdenum, Nickel, Tungsten 6) Nuclear: Uranium 7) Electronic: Mercury
8) Chemical: Bromine, Phosphate, Potash, Sulfur, Florspar, Pyrites, Salt 9) Industrial: Asbestos, Cement, Gypsum, Talc
Lifetimes of Reserves
Elements Essential to LMe Elements essential to both animal and plant life are marked with an asterisk in the preceding summary. Sodium is essential to animals but is not recognized as essential to plants. Boron is known to he essential in plant growth, but i t i s not known to be essential in animals. In question a t present is whethel chromium is essential in higher animals. Vanadium appear? to be essential for the growth of certain algae; i t also is an important part of a protein found in tunicates, a group 01 marine invertehrates.
Assuming future consumption a t the current rate, the dates (to the nearest five vears) a t which current metal reserves could be exhausted are estimated to be Element,
Year
Element
Year
Element
Year
Amounts of Elements Present in the Ocegns Estimates are that about 7 X 1012kg of carbon in the forn of living matter and about 5.5 X 1019kg of dissolved inorganil: salts are present in the seas. The average concentrations of tht most common ions in sea water (in parts per million) are: If the present accelerated consumption continues, these dates could all be reduced, some by as much as several hundred years. Hopefully, new sources will be discovered and improved technology will make it economical to extract certain metals from lower grade ores than now is possible. Meanwhile, critical shortages of copper, lead, molybdenum, tungsten and zinc can be expected by 1985. From this, i t is evident that the search for new sources, efficient recycling and the development of substitutes for certain metals are necessary. "Conservation of Resources," Special Publication No. 27, The Chemical Society, London 1976.
concentration
cancentration ion Na+
1.05 X 1v 1.9 X 10'
CIMg2+
ion
(PP~)
1.35 X
lo3
S (mostly 8.85 X lo2 as sod2-) Ca2+ 4.0 X lo2
Kf Si (mostly as HzSiO2-) N (mostly as NOs-) P (mostly pop) FeX+
eoneentration
( P P ~ ) ion
3.8 X
(PP~)
lo2
3.0
Maxi 1 X
0.5
Zn2+ 1X 10W
7 x 10-2 cu2+3 x lor3 1X 10W MnT+2 X 10W3 CO"+ 1 x
Elemental Composition of the Human Body The elemental composition of a healthy human adult of 70 kg can he summarized a s follows. Elements presented in amounts between: 1 X lo4 and 63 x 10' ppm: oxygene,carbon*,hydrogen', nitrogen*, calcium* 4 X 10%and 7 X lo3 ppm: sulfur*,phosphorus*, sodium, potas-
T h e concentration of elemental oxygen, 02, is variable; it1 concentration may be as high as 9.1 ppm in surface waters a' 1O0C.The quantities of nitrogen and phosphorus in the oceans limit the amount of the ~ x y ~ e n - ~ r o d uphytoplankton cin~ tha can exist there. Blown, Jr., G. W., "Dotorifleation in the Marine Environment." in Biochemical and Bio phyaical Penpeetives in Marine Biology. Volume 3, Academic Press, N e w Yorh 1976.
Volume 54. Number 9, September 1977 1 551
