European freshwater ecosystems have undergone significant human-induced and environmentally-driven variations in nutrient export from catchments throughout the past five decades, mainly in connection with changes in land-use, agricultural practice, waste water production and treatment, and climatic conditions. We analysed the relations among concentration of total phosphorus (TP) in the Slapy Reservoir (a middle reservoir of the Vltava River Cascade, Czechia), and socio-economic and climatic factors from 1963 to 2015. The study was based on a time series analysis, using conventional statistical tools, and the identification of breaking points, using a segmented regression. Results indicated clear long-term trends and seasonal patterns of TP, with annual average TP increasing up until 1991 and decreasing from 1992 to 2015. Trends in annual, winter and spring average TP concentrations reflected a shift in development of sewerage and sanitary infrastructure, agricultural application of fertilizers, and livestock production in the early 1990s that was associated with changes from the planned to the market economy. No trends were observed for average TP in autumn. The summer average TP has fluctuated with increased amplitude since 1991 in connection with recent climate warming, changes in thermal stratification stability, increased water flow irregularities, and short-circuiting of TP-rich inflow during high flow events. The climate-change-induced processes confound the generally declining trend in lake-water TP concentration and can result in eutrophication despite decreased phosphorus loads from the catchment. Our findings indicate the need of further reduction of phosphorus sources to meet ecological quality standards of the EU Water Framework Directive because the climate change may lead to a greater susceptibility of the aquatic ecosystem to the supply of nutrients.

• MeSH
• Economics MeSH
• Phosphorus analysis   MeSH
• Lakes * MeSH
• Environmental Monitoring MeSH
• Climate * MeSH
• Seasons MeSH
• Fresh Water chemistry   MeSH
• Publication type
• Journal Article MeSH
• Names of Substances
• Phosphorus MeSH

Nitrate contamination of surface water and shallow groundwater was studied in transboundary (Russia/Ukraine) catchment with heterogeneous land use. Dominant sources of nitrate contamination were determined by applying a dual δ 15N-NO3 and δ 18O-NO3 isotope approach, multivariate statistics, and land use analysis. Nitrate concentration was highly variable from 0.25 to 22 mg L-1 in surface water and from 0.5 to 100 mg L-1 in groundwater. The applied method indicated that sewage to surface water and sewage and manure to groundwater were dominant sources of nitrate contamination. Nitrate/chloride molar ratio was added to support the dual isotope signature and indicated the contribution of fertilizers to the nitrate content in groundwater. Groundwater temperature was found to be an additional indicator of manure and sewerage leaks in the shallow aquifer which has limited protection and is vulnerable to groundwater pollution.

• Keywords
• Anthropogenic sources, Land use, Multivariate statistics, Nitrate isotopes, Seversky Donets, Ukraine,
• MeSH
• Water Pollutants, Chemical analysis   MeSH
• Nitrates analysis   MeSH
• Manure analysis   MeSH
• Isotopes analysis   MeSH
• Environmental Monitoring methods   MeSH
• Sewage chemistry   MeSH
• Groundwater chemistry   MeSH
• Fresh Water chemistry   MeSH
• Agriculture MeSH
• Publication type
• Journal Article MeSH
• Geographicals
• Russia MeSH
• Ukraine MeSH
• Names of Substances
• Water Pollutants, Chemical MeSH
• Nitrates MeSH
• Manure MeSH
• Isotopes MeSH
• Sewage MeSH