A comparison has been made between the metal pollution in several European rivers in various stages of clean-up and management for the period of 1980-1996. The investigated rivers were Rhine, Meuse, Scheldt, Weser and Elbe. The results from this comparison showed that the simple statement that characterizes the river Elbe as ‘the most polluted river in Europe’ is a simplification. Three independent methods are presented to estimate point and diffuse source contributions in emissions and riverine transports. All methods were applied to the Elbe and Rhine rivers to estimate the contribution of point and diffuse sources for six heavy metals. The results of the source apportionment estimates show that there are temporal differences in source strength and source origin. A dramatic drop in industrial inputs and inputs from waste water treatment plants can be observed. The comparison of all methods shows some differences, which might be caused by retention processes (such as sedimentation) in the river system.

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Abstract:Pollutant transport and management in the Rhine and Elbe basins is still of international concern, since certain target levels set by the international committees for protection of both rivers have not been reached. The analysis of the chain of emissions of point and diffuse sources to river loads will provide policy makers with a tool for effective management of river basins. The analysis of large river basins such as the Elbe and Rhine requires information on the spatial and temporal characteristics of both emissions and physical information of the entire river basin. In this paper, an analysis has been made of heavy metal emissions from various point and diffuse sources in the Rhine and Elbe drainage areas. Different point and diffuse pathways are considered in the model, such as inputs from industry, wastewater treatment plants, urban areas, erosion, groundwater, atmospheric deposition, tile drainage, and runoff. In most cases the measured heavy metal loads at monitoring stations are lower than the sum of the heavy metal emissions. This behaviour in large river systems can largely be explained by retention processes (e.g. sedimentation) and is dependent on the specific runoff of a catchment. Independent of the method used to estimate emissions, the source apportionment analysis of observed loads was used to determine the share of point and diffuse sources in the heavy metal load at a monitoring station by establishing a discharge dependency. The results from both the emission analysis and the source apportionment analysis of observed loads were compared and gave similar results. Between 51% (for Hg) and 74% (for Pb) of the total transport in the Elbe basin is supplied by inputs from diffuse sources. In the Rhine basin diffuse source inputs dominate the total transport and deliver more than 70% of the total transport. The diffuse hydrological pathways with the highest share are erosion and urban areas.

The Neurotoxin lead has been emitted in large amounts into the environment over decades.To what extent this long-term pollution affects environmental systems is relatively unknown. Despite decreasing atmospheric pollution, soil and freshwater systems still indicate high lead concentrations. This study provides a preliminary estimation of annual overland lead fluxes originating from atmospheric pollution in the Elbe basin in Central Europe during the period 1958-1995. The transport into aquatic systems of lead originally deposited in the soil is assessed. Three pathways from rural areas into the river system were considered: erosion, direct runoff and direct atmospheric deposition. For this purpose, a modified mesoscale empirical-conceptual model for heavy-metal transport was applied. The results indicated that the total lead fluxes decreased after a peak in the 1970s. The emissions into the Elbe and its tributaries due to direct deposition showed a clear decline caused by decreasing atmospheric pollution since the 1970s. On the contrary, overland lead fluxes via erosion and direct runoff slightly increased. They were mostly influenced by the hydrometeorological and topographical conditions and less by the intensity of atmospheric input in a given year. Model results showed a steady background accumulation in the soils for the investigation period with a positive temporal and spatial correlation to atmospheric deposition. We conclude that lead-control policies were successful only to a certain degree. In order to reduce pollution by highly sorptive, particle-bound substances such as lead, effort should focus not only on minimizing atmospheric emissions, but also on minimizing soil erosion.