Compositions and concentrations of dissolved organic matter, selected elements and anions in German drinking waters

Dissolved organic matter (DOM) in water resources can lead to various drinking water quality issues, including undesirable color, taste, and odor, while also enhancing the mobility of heavy metals and promoting the formation of disinfection byproducts. This study investigated DOM concentrations and compositions in German drinking waters using fluorescence spectroscopy and size-exclusion chromatography coupled with organic carbon detection (LC-OCD). Additionally, the occurrence of selected elements and other inorganic ions were studied. Eighty-nine (89) drinking water samples were collected with the help of residents across Germany. The study revealed that DOM concentrations ranged from 0.3 to 5.7 mg/L, primarily due to humic substances. DOM fractions identified using LC-OCD and fluorescence spectroscopy showed a correlation, indicating that an increase in organic carbon resulted in an increase in fluorescent DOM, as expected due to the aromatic character of humic substances. Heavy metal concentrations in drinking waters were below the regulatory limits set by the German Drinking Water Ordinance (TrinkwV) for safe drinking water, except for one example of a lead concentration, which was 16.2 μg/L. No specific relation was found between the sources of drinking water (including surface water, groundwater, and bank filtrate) and the concentration and composition of DOM, as well as the occurrence of heavy metals. However, correlations between vanadium and chromium, nickel and lead, calcium and magnesium, and calcium and sulfate suggested that these components may share common sources or exhibit similar geochemical behaviors.