The use of liquid chromatography in the study of cadmium speciation in soil solutions from polluted soils

Summary Chromatographic methods were used in an attempt to identify the various species of cadmium in soil solution. Exclusion and reverse‐phase chromatography using HPLC showed that cadmium existed in the form of low‐molecular weight, highly polar species. Ion‐exchange chromatography was used to divide soil solution cadmium into cationic, anionic and neutral species. Cadmium was found to be mainly in the form of inorganic cationic species, including the free ionic form, Cd 2+ , and some as neutral species, possibly organic as well as inorganic, especially in soils of higher pH. Anionic species were relatively unimportant. These results showed general agreement with those of other authors using computer models to predict cadmium speciation in soil solution.