Phosphor in Flie\gewÄssern und seine analytische Bestimmung

Summary

The aim of this work was: 1) to get information on the applicability of different analytical methods for the determination of P and P species, 2) to supply a general view of the concentration ranges of P in some of the major rivers of the Federal Republic of Germany. About 170 river samples have been analysed for dissolved (<0.45 Μm) species. The methods applied were the photometric determination of o-HPO ²⁻₄ as molybdophosphate, the determination of o-HPO ²⁻₄ by means of ion chromatography and the P determination by inductively coupled plasma spectrometry. In addition, digestion of the samples was used before the simultaneous application of the methods to control the results. In order to get some insight into the kind of P compounds present in surface waters, sorption on polystyrene was used. All methods applied led to data of acceptable precision and turned out to be well suited for the concentration ranges present in rivers. Dissolved total P (P_T) was between 0.1 and 1 mg/l in all cases. About 50 to 70% of p_T was present as o-HPO ²⁻₄ (P_o-P). The fraction bound to humic matter was mostly less than 1% of P_T. In case of the river Rhine the concentration of P_T and P_o-P increased along its course. In the Danube there seems to be a reverse tendency. The rivers Ruhr, Main and Neckar and especially the Emscher, which all contribute to the river Rhine, show significantly higher concentrations. There seems to be a concentration minimum during the summer months in the river Rhine. Further application of speciation methods in combination with hydraulic data can lead to a more detailed understanding of the fate of P compounds in river systems and to valid P balances.