The Characterization of Dissolved Organic Matter in Reclaimed Water and Its Influence on Copper Toxicity

Water samples were collected from five phases of treatment in a municipal sewage reclaimed water plant and the DOM was characterized. Results indicated that the components and properties of DOM varied notably with sequential treatments, such as the fluorescence intensity, the molecular weight and the total acidity. Meanwhile the accumulation of Cu in Daphnia magna was analyzed following exposure to samples spiked with 50 µg/L copper, which were decreased by the presence of DOM in those water samples. Furthermore, this study found significant associations between fluorescence intensity and Cu accumulation (r2 = 0.778, p < 0.05), while increased total acidity was found to enhance the unit total organic carbon-Cu accumulation (r2 = 0.979, p < 0.01). This study provides useful information on the safety and effective management of reclaimed water as a potential water resource.