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เอกสารมาตรฐาน
สหรัฐอเมริกา
APHA
SMWW 3500-Pb
Lead
2023
3
Standard methods for the examination of water and wastewater (543.3 APHA 24th ed. Ref. Treatises&monographs FL2)
Lead (Pb) is the fifth element in Group IVA in the periodic table. It has an atomic number of 82, an atomic weight of 207.19, and valences of 2 and 4. The average abundance of Pb in the earth’s crust is 13 ppm; in soils it ranges from 2.6 to 25 ppm; in streams it is 3 μg/L, and in groundwaters it is generally <0.1 mg/L. Lead is obtained chiefly from galena (PbS). It is used in batteries, ammunition, solder, piping, pigments, insecticides, and alloys. Lead also was used in gasoline for many years as an antiknock agent in the form of tetraethyl lead...