Understanding Partition Coefficient, Kd, Values, Appendix C

APPENDIX C Partition Coefficients For CadmiumAppendix C Partition Coefficients For Cadmium C.1.0 Background Cadmium K values and some important ancillary parameters that have been shown to influence dcadmium sorption were collected from the literature and tabulated. Data included in this data set were from studies that reported K values and were conducted in systems consisting of dC Natural soils (as opposed to pure mineral phases)C Low ionic strength solutions (<0.1 M)C pH values between 4 and 10C Solution cadmium concentration less than 10-5 MC Low humic materials concentrations (<5 mg/l) C No organic chelates (such as EDTA)A total of 174 cadmium K values were found in the literature (see summary in Section C.3.0). dAt the start of the literature search, attempts were made to identify K studies that included dancillary data on aluminum/iron-oxide concentrations, calcium and magnesium solution concentrations, pH, cation exchange capacity (CEC), clay content, redox status, organic matter concentrations and sulfide concentrations. Upon reviewing the data and determining the availability of cadmium K measurements having ancillary information, K values were collected d dthat included information on clay content, pH, CEC, total organic carbon (related to organic matter), and dissolved cadmium concentrations. The selection of these parameters was based on availability of data and the possibility that the parameter may impact cadmium K values. Of ...