The report below has these coefficients for various sediment types:

De Vries, W., Posch, M., 2003. Derivation of Cation Exchange Constants for Sand,

Loess, Clay and Peat Soils on the Basis of Field Measurements in the

Netherlands. In: Alterra-report, vol. 701. Alterra Green World research, Wageningen,

50 p.

thanks it is indeed a very interesting and thorough report! Thank you very much for sharing!