An East-West perspective on riverine loads of nutrients in the Vistula and Rhine basins

Abstract

Measures proposed to reduce the load of nutrients to the Baltic Sea focus on the removal of point emissions through introduction of environmental technology in the eastern and southern parts of the drainage basin. This article draws attention to the mixed success of Western European river basin management by comparing water quality trends and turnover of nutrients in the Vistula and Rhine basins. Removal of point sources in the Rhine basin has caused a marked drop in the concentrations of phosphorus and ammonium nitrogen, whereas the long-term upward trend in the concentration of nitrate was broken only recently. As compared to the Vistula river, the Rhine is still in some respects more polluted. Expressed as area-specific export, the riverine load of nitrate from the Vistula basin is only about one sixth of that of the Rhine basin. The area-specific export of phosphorus is comparatively higher in the Vistula, but still only half of that of the Rhine. In addition to the lower input of nutrients in the Eastern European agriculture, the much lower runoff in the Vistula basin is an important explanation to the observed differences. Furthermore, in-stream processes, such as sedimentation of phosphorus, play an important role.