Contamination by disinfection byproducts (DPBs) and microbiological quality of dialysis water: a study in an Italian hospital dialysis service

Maintaining a high standard of quality of dialysis fluid has been shown to be difficult. For this reason, an evaluation of the microbiological quality (total bacterial count at 22 degrees C and 37 degrees C, pyrogenic Pseudomonas, Staphylococcus, Acinetobacter and Enterobacteriaceae) and contamination by disinfection byproducts, of dialysis fluids was carried out in a hospital dialysis service in Arezzo (Italy). The analysis was carried out in different points of the water treatment system used for the preparation of dialysis fluids. Results show diffuse microbiological contamination especially at the point of entry of the dialyzer monitor; Staphylococcus and Pseudomonas were found to be the most frequent contaminants due to the presence of biofilms in the water system, while pyrogenic bacteria were found to be within regulatory limits. Trichloroethane and trichloroethylene were absent but traces of carbon tetrachloride, percloroethylene and bromoform were found; these were outnumbered by trialomethanes (chloroform at point of entry decalcifier: mean 90.14 microg/L). Contamination by trialomethanes decreased at the end of the distribution system (mean chloroform 8.55 microg/L). The yearly level of exposure of a dialysis patient to low molecular weight volatile halogenated organics (VHOs) that are able to pass the dialyser membrane, was therefore estimated to be approximately 100 mg.