CFR / 
Title 40
 / 
Part 129
 / 
Sec. 129.3 Abbreviations.
The abbreviations used in this part represent the following terms:
lb=pound (or pounds)g=gram[micro]g/l=micrograms per liter (1 one-millionth gram/liter)kg=kilogram(s)kkg=1000 kilogram(s)