Abstract: Objective he quality of RO water directly affects the safety and complications in hemodialysis patients. To find out the cause of chemical contaminations leading to the water unsuitable for dialysate and its solving approaches, the guidelines for selection of water purification system, and the methods for maintenance of the system, we analyzed the chemical contaminants in the recent 10 years in RO water from Beijing Municipal Hospital Hemodialysis Center. Methods Al, Cu, Ba, Zn, As, Pb, Ag, Sn, Cd and Cr were tested with ICP_MS method, Se and Hg with HG-AAS method, R-Cl2 and X-NH2 with spectrophotometry method, F, NO3- and SO4-2 with IC method, and Ca, Mg, K and Na with ICP-AES method. Results Chemical contaminants exceeded the allowing amounts in RO water were detected in 19 hemodialysis centers in 2003, and decreased to 4 centers in 2004. In recent two years, all of the hemodialysis centers in Beijing area are using
the RO water matched the chemical contamination standards. Conclusion Under the management and guidance of Hemodialysis Quality Control and Improvement Center, high quality water purification system has been widely adopted by hemodialysis centers. Routine maintenance of hemodialysis equipment and monitoring of water quality are the key steps to assure the quality of RO water.