Aluminium and fluoride in the water supply and their removal for haemodialysis.

Aluminium and fluoride in the water supply and their removal for haemodialysis have been investigated in the Trent Region, U.K., and wide variations noted. The efficiency of removal of these elements from the mains water supplying home haemodialysis units by different water treatment systems currently installed has been assessed and a follow-up study performed 8 months later. Some improvement in water treatment was noted, with the percentage of home dialysis units receiving waters within the proposed European Economic Community guidelines for aluminium rising from 61.7 to 72.1%. Removal of fluoride by the different treatment mechanisms is analogous to that for aluminium. A comparison of new and older water treatment systems has shown that there is a deterioration in performance with use. However, some cases of poor removal may be due to the installation of unsuitable equipment, or, more probably, due to a change in the waters used to supply the different homes. Thus, adequate maintenance of equipment and frequent sampling of both untreated and treated waters are required in order to maintain the provision of waters suitable for the preparation of dialysate.

Aluminium release from the Sorbsystem D-3160 and D-3260 cartridges.

Recent clinical information indicates that the aluminium level of patients' serum can rise while they are being treated with the Sorbsystem haemodialysis system. Further evidence suggests that the quality of aluminium removed from the dialysing fluid by the sorbent cartridge utilized in this equipment is time-dependent. Evaluation of the sorbent cartridges D-3160 and D-3260 has shown that ultimately aluminium is satisfactorily removed from the dialysing fluid. However, the time taken to achieve the safe condition of less than 30 micrograms/litre of aluminium is dependent on the quantity of aluminium washed out from a new cartridge before being reabsorbed, and the highly variable quantity contained in the diluting water. The results have also shown that the level of aluminium recommended by the DHSS in April 1982 (30 micrograms/litre) is not reliably attained following the manufacturer's recommended pretreatment, and a further 60 min of operation in the 'dialyse' mode is necessary. It should be noted that, as a result of evaluation of the Sorbsystem, the DHSS have issued guidelines on the use of this equipment.

A review of, and improvements to, the techniques of trace element analysis of raw water for home dialysis.

The optimum operating conditions for the measurement of aluminium and iron concentrations in water by atomic absorption spectrometry have been determined experimentally. The characteristics of an ion-selective electrode for the measurement of fluoride have also been investigated. Contrary to other work, the addition of acid to samples did not improve their storage stability, although the acid-washing of polyethylene containers is recommended for the storage of water.