- Trace elements, most notably aluminium and strontium, have been noted for their role in the development of secondary bone disorders in haemodialysis patients. Due to the large dosages of calcium required for the maintenance of dialysis patients, this study investigated whether the source of calcium chosen for supplementation, including the form of administration (i.e. chewable forms or capsules), has an influence on the total amount of strontium and aluminium ingested daily. A convenience sample of various calcium supplement tablets and antacids was acquired, and strontium and aluminium quantification was performed by wavelength-dispersive X-ray fluorescence spectrometry. The use of readily available oyster shell-based calcium was found potentially to increase the total amount of ingested strontium substantially with concentrations reaching (2.26 +/- 0.05) (mg Sr).(g Ca)(-1), while the use of antacids or chewable supplements was found to contain concentrations reaching as high as (1.2 +/- 0.3) (mg Al).(g Ca)(-1) in the supplements analysed within this work. It is recommended that the choice of calcium supplement prescribed to individuals undergoing haemodialysis be closely regulated and noted as a possible factor in the prevalence of bone disorders reported in these patients.