Fate of Sulfate in the Course of Japanese Drinking Water Purification Plants −Implications for Dialysis Therapy−

Abstract

Sulfate is currently not regulated by Japanese water quality standards but could pose adverse health effects to dialysis patients if it remains in high concentration (more than 100 mg/L) in dialysis water and dialysis fluid prepared at healthcare facilities (HCFs). In this study, we obtained sulfate levels in raw water and finished water at Japanese drinking water purification plants (DWPPs) from “Statistics on Water Supply (Water Quality)” in FY2012-2014, and then estimated increases in sulfate by water purification processes. Impact of water treatment chemicals containing sulfate (e.g., alum for coagulation and sulfuric acid for pH adjustment) was also evaluated by water sampling at selected three DWPPs. In FY2012-14, sulfate levels in finished water were mostly less than 50 mg/L; however, sulfate at 18 out of 1,497 DWPPs exceeded 100 mg/L. Increases in sulfate level by dosing of the water treatment chemicals were typically less than 10 mg/L, and other part of the sulfate in finished water came from raw water. These information on water quality should be shared with medical professionals conducting the dialysis therapies, and it would be worthwhile to collaborate with them in water quality management at HCFs.