Survey of the "Other" inorganic constituents

While many drinking water utilities have encountered and dealt with arsenic, total dissolved solids (TDS), nitrates, and radionuclides, there are numerous "other" inorganic constituents that could affect water quality and the subsequent choice of treatment processes. A national survey was conducted to determine what "other" inorganics are of concern. Data representing responses from 67 public water systems are presented. The most commonly reported "other" inorganic issues were iron and manganese, pH adjustment, hardness, and anions (including bromide, chloride, and sulfate). Utilities with groundwater sources generally had the most issues with iron, manganese, and hardness, while utilities treating surface water or combined sources had the most issues with various anions. Utilities with concerns involving common inorganic contaminants of longstanding concern, such as a utility dealing with an iron and manganese problem for a long time, or with a single inorganic contaminant concern rated available technologies and information higher than utilities with multiple concerns or utilities concerned with various trace constituents. Survey respondents indicated that the most information and technical solutions were available for iron/manganese and hardness, the first and third most commonly cited inorganic contaminants, respectively. This suggests that future research could be directed towards pH adjustment, selected anions, and antimony to improve information and treatment solutions. In general, available information was rated higher than the quality of technical solutions, which suggests that future efforts by researchers (possibly Water Research Foundation, American Water Works Association, Water Environment Federation, or Environmental Protection Agency) should not be limited to technology dissemination, but should include research and development efforts.