สิ่งแวดล้อม มลภาวะ ของเสีย
เอกสารมาตรฐาน
สหรัฐอเมริกา
APHA
SMWW 3500-Ba
Barium
2023
1
Standard methods for the examination of water and wastewater (543.3 APHA 24th ed. Ref. Treatises&monographs FL2)
Barium (Ba) is the fifth element in Group IIA in the periodic table. It has an atomic number of 56, an atomic weight of 137.33, and a valence of 2. The average abundance of Ba in the earth’s crust is 390 ppm; in soils it is 63 to 810 ppm; in streams it is 10 mg/L; in US drinking waters it is 49 μg/L; and in groundwaters it is 0.05 to 1 mg/L. It is found chiefly in barite (BaSO4) or in witherite (BaCO3). Barium’s main use is as a constituent of mud slurries used when drilling oil and exploration wells, but it is also used in pigments, rat poisons, pyrotechnics, and in medicine...