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APHA
SMWW 3500-Co
Cobalt
2023
1
Standard methods for the examination of water and wastewater (543.3 APHA 24th ed. Ref. Treatises&monographs FL2)
Cobalt (Co) is the second element in Group VIII in the periodic table. It has an atomic number of 27, an atomic weight of 58.93, and valences of 1, 2, and 3. The average abundance of Co in the earth’s crust is 29 ppm; in soils it is 1.0 to 14 ppm; in streams it is 0.2 μg/L; and in groundwaters it is 1 to 10 μg/L. Cobalt occurs only sparingly in ores, usually as the sulfide or the arsenide. It is widely used in alloys of various steels, in electroplating, in fertilizers, and in porcelain and glass...