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Large‐scale Zonal Rotors in Soil Science
Author(s) -
Francis C. W.,
Brinkley F. S.,
Bondietti E. A.
Publication year - 1976
Publication title -
soil science society of america journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.836
H-Index - 168
eISSN - 1435-0661
pISSN - 0361-5995
DOI - 10.2136/sssaj1976.03615995004000050045x
Subject(s) - sediment , soil water , phaseolus , chemistry , environmental chemistry , bulk density , environmental science , soil science , geology , agronomy , paleontology , biology
A large‐scale zonal rotor was developed to band isopycnically soils and sediments in nonaqueous density gradients. The major advantage of such a rotor over conventional swinging bucket rotors is that relatively large quantities may be segregated; 15 g in large‐scale zonal rotors vs. 0.25 g per centrifugal tube with swinging bucket rotors. The rotor was used to isolate and identify soil‐sediment reaction sites of 137 Cs, 60 Co, and 106 Ru. The 137 Cs was found to be associated with micaceous minerals, the 60 Co with Fe‐sesquioxides, and the 106 Ru with organic rich soil components. An edge‐unloading rotor containing sucrose gradients (max. density 1.3 g/cm 3 ) was used in a rate‐zonal mode to isolate Cd and Ni enriched fractions of sediment taken near the wastewater discharge of a Cd‐Ni battery plant. In sediments enriched in carbonates, Cd was found to be largely associated with the carbonates while Ni was concentrated in the organic rich soil components. Biological availability of Cd was evaluated by growing bush bean seedlings ( Phaseolus vulgaris L.) in nutrient solutions containing density fractions of a soil clay. Density gradient separations using large‐scale rotors were shown to be a valuable adjunct to chemical extraction techniques for characterizing trace element interactions with soils and sediments.