title: Rising trends of dissolved organic matter in drinking-water reservoirs as a result of recovery from acidification in the Ore Mts., Czech Republic.
abstract: The concentration of chemical oxygen demand (COD), a common proxy for dissolved organic matter (DOM), was measured at seven drinking-water reservoirs and four streams between 1969 and 2006. Nine of them showed significant DOM increases (median COD change +0.08 mg L(-1) yr(-1)). Several potential drivers of these trends were considered, including air temperature, rainfall, land-use and water sulfate concentration. Temperature and precipitation influenced inter-annual variations, but not long-term trends. The long-term DOM increase was significantly associated with declines of acidic deposition, especially sulfur deposition. Surface water sulfate concentrations decreased from a median of 62 mg L(-1)-27 mg L(-1) since 1980. The magnitude of DOM increase was positively correlated with average DOM concentration (R(2) = 0.79, p < 0.001). Simultaneously, DOM concentration was positively correlated with the proportion of Histosols within the catchments (R(2) = 0.79, p < 0.001). A focus on the direct removal of DOM by water treatment procedures rather than catchment remediation is needed.
authors.affiliation: Czech Geological Survey, Department of Environmental Geochemistry and Biogeochemistry, Klárov 3, 118 21 Prague, Czech Republic. filip.oulehle@geology.cz
authors.forename: Filip
authors.initials: F
authors.lastname: Oulehle
authors.forename: Jakub
authors.initials: J
authors.lastname: Hruska
mesh_terms: D018153:Czech Republic; D060766:Drinking Water / Q000737:chemistry*; D009930:Organic Chemicals / Q000737:chemistry*; D012989:Soil Pollutants / Q000737:chemistry; D012995:Solubility; D014874:Water Pollutants, Chemical / Q000737:chemistry*; D014877:Water Pollution, Chemical / Q000032:analysis
chemical_list: D060766:Drinking Water; D009930:Organic Chemicals; D012989:Soil Pollutants; D014874:Water Pollutants, Chemical