TRACE-ELEMENTS AND MICROPOLLUTANT ANIONS IN THE DIALYSIS AND REINFUSION FLUID PREPARED ONLINE FOR HEMODIAFILTRATION

Exposure to the trace elements and micropollutions of tap water may be very considerable in dialysis patients. As few data on trace elements in reinfusion and dialysis fluid for haemodiafiltration (HDF) have be en reported, we studied nine trace elements (mu g/l; Al, As, Cd, Cr, C u, He, Pb, Se, Zn) and five anions (mg/l; F-, NO2-, NO3-, PO43-, SO42- ) in tap water, in water after two passages of reverse osmosis (2RO), in dialysate and in on-line prepared reinfusate. NO3- and SO42- were s omewhat elevated in our tap water (22.2 +/- 7.6 and 21.8 +/- 11.3 mg/l ) but decreased (P < 0.001) after 2RO (1.4 +/- 1.5 and 0.9 +/- 1.1 mg/ l); the other anions, which were at a very low level, remained unchang ed. All trace elements decreased, with statistical significance only f or Al, Cr and Zn from 14.9 +/- 19.9, 2.6 +/- 0.6 and 35.1 +/- 41.1 mu g/l to 3.2 +/- 2.1, 0.2 +/- 0.2 and 3.5 +/- 4.8 mu g/l, respectively. Due to impurities in concentrate salts for Al (5.4 +/- 3.1), Cr (0.5 /- 0.4) and SO42- (2.4 +/- 1.8), greater concentrations were found in dialysate and reinfusate than in tap water after 2RO (P < 0.03). For a ll measurements, trace elements and anions were at acceptable levels a ccording to international standards. Simultaneous determinations of tr ace elements at inflow (Din) and outflow (Dout) of the dialysate as we ll as in plasma or in whole blood at the beginning of on-line HDF docu mented Dout/Din > 1 for Al, Cu and Zn and a positive gradient between the concentration in blood and dialysate inlet. In conclusion, our dia lysate and reinfusate can be considered safe regarding trace elements and micropollution: two passages through reverse osmosis reduces the c oncentrations of trace elements and anions. The impurities of concentr ates are acceptable. Accumulation or depletion of trace elements shoul d be evaluated after longitudinal studies of plasma concentrations.