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Phosphorus concentration in the Orlík and Slapy reservoirs: a result of socio-economic trends in the catchment and climate change
Hejzlar, Josef ; Jarošík, Jiří ; Kopáček, Jiří ; Vystavna, Yuliya
Based on existing phosphorus data series in the Slapy and Orlík reservoirs and their main tributaries, we reconstructed P inputs to the reservoirs from the catchment during 1961–2016 and compiled\nempirical models of P retention. P concentrations in both reservoirs increased from the 1960s to 1991 and then declined, with the Slapy Reservoir having a significantly increased year-on-year\nvariability. Trends in the increase and decrease of P reflected the socio-economic development in the Vltava river basin, in particular sewerage, wastewater discharges, fertilizer application, livestock,\nand fishpond fisheries. In the Slapy reservoir after 1991, the P concentrations increased during wet summers and created conditions for growth of phytoplankton, whereas in dry summers they\ndecreased to mesotrophy. Climatic and hydrological processes have now apparently begun to compete with a generally decreasing P pollution and support eutrophication despite the drop in P loads from the catchment.
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Trends in the balance and material flows of phosphorus in the Czech Republic.
Hejzlar, Josef
In developed countries, many voices call for increasing the recycling of phosphorus (P) that is a strategic raw material for agriculture and other production sector; phosphorus is also causing environmental problems, for example. eutrophication. Using the methodology of material flow analysis, van Dijk et al. (Sci. Total Environ. 2016, 552: 1078-1093) quantified the main flows and stocks of P in 27 states of the European Union. The contribution presents and discusses data from that publication for the material flows P in the Czech Republic (CR) and compared with the EU. The P balance of CR shows the dependence on imported P through mineral fertilizers (1 kg/ca/yr), food and feed (1.5 kg/ca/yr) and also draws attention to significant environment losses and unused recycling potential. For example, municipal sludge (0.4 kg/ca/yr) and bone meal (0.25 kg/ca/yr) could replace 70% of the P amount in applied mineral fertilizers. P recycling rate in CR in comparison with EU-27 is below average (68% in livestock production, 21% in food production, 10% for human consumption). Agricultural production in CR still uses P reserves in the soil of mineral fertilizers in the past.
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