Forty-four elements (Al, Sb, As, Ba, Be, B, Br, Cd, Ce, Co, Cr, Cs, Cu, Eu, Ga, Au, Hf, In, Ir, Fe, La, Lu, Mn, Hg, Mo, Nd, Ni, Pb, Rb, Sm, Sc, Se, Ag, Sr, Ta, Tb, Tl, Th, Sn, W, U, V, Zn, Zr) have been determined in the dialysate for hemodialysis (HD) and fluids for hemofiltration (HF) and continuous ambulatory peritoneal dialysis (CAPD). Multiple determinations have been performed for each dialysis fluid. Several trace elements (TE) showed remarkably elevated average levels; moreover, different bathes of the same commercial product may present a wide variability in TE concentration. The data point out the pivotal role of dialysis fluids in contributing to TE imbalance in dialysis patients and allow the assessment of the potential element exposure of patients on regular dialytic treatment. Patients on HD treatment would be exposed on a weekly basis to milligrams of Al, B, Ba, Br, Cu, Fe, Ni, Pb, Rb, Sr and Zn; on HF, the highest exposures are due to Al, B, Br, Fe, Pb and Zn; on CAPD to B, Br, Fe and Zn. The weekly exposure for several TE appears to be 50- to 12,000-fold higher than the corresponding values on the amount absorbed via the diet (HD: Au, Ba, Be, Ce, Ga, La, Sc, Ta, Th, V, Zr; HF: Be, Ce, Ta, Th, V, Zr; CAPD: Au, Be, Ce, Ga, V, Zr).(ABSTRACT TRUNCATED AT 250 WORDS)