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Cases of severe eutrophication are still observed in European surface waters even though tough regulation has been in place since the beginning of the 1990s to control nutrient losses and inputs in the environment. The purpose of this paper is to evaluate the evolution since 1991 of the quality of the water entering European seas in terms of the concentration of major nutrients (nitrogen and phosphorus), and to analyze the effectiveness of implemented national/international measures and EU legislation in reducing water nutrient pollution. Despite the reduction in large portions of the European territory of agricultural nutrient applications and nutrient point source emissions, the impact on water quality is limited. It is shown using two large river basins that this lack of response for nitrogen, and nitrate in particular, between the reduction of the nitrogen surplus and the recovery of water quality is partly explained by the lag time due to transfer of nitrates in the unsaturated and saturated zones and storage in the soils and aquifers. In order to monitor efficiently the impact of policy implementation on water quality, the Nitrates Directive and the Urban Waste Water Treatment Directive in particular, it is recommended to use long term permanent monitoring stations to be able to separate the impact of climate variability from that of policy implementation. It is also recommended to investigate and develop harmonized methodologies for estimating the lag time in order to come up with realistic estimates of response time of water bodies due to the implementation of measures., (Copyright © 2011 Elsevier B.V. All rights reserved.)

Abstract: The characterisation of pollution sources impact on water quality and the implementation of river basin management plans require an analysis of the basin status including the dynamic of nutrient transfer and the relative significance of the different sources of pollution. Models can contribute in understanding the sources and the processes responsible for pollution, and identifying the areas of concern. A variety of methods have been used to model the nitrogen pressure in river basins. In this study we describe a comparison between two methodologies: a statistical model and the physically-based SWAT model. The two models were calibrated on the Wash catchment (UK), 8900km2. The nitrogen losses from land to surface waters and the source apportionment of riverine nitrogen load were estimated by the two approaches, and the results were compared. Moreover their potentiality for evaluating management strategies was analysed. [Copyright &y& Elsevier]

This study describes a source apportionment methodology for nitrogen river transport. A statistical model has been developed to determine the contribution of each source (punctual and diffuse) of nitrogen to river-mouth transport. A non-linear regression equation was developed, relating measured nitrogen transport rates in streams to spatially referenced nitrogen sources and basin characteristics. The model considers applied fertilizer, atmospheric deposition and point discharges as sources, and winter rainfall, average air temperature, topographic wetness index and dry season flow as basin characteristics. The model was calibrated in an area of 8913 km² in East Anglia (UK). In the studied area, the average contribution of agriculture to the nitrogen load is estimated around 71%. Point sources and atmospheric deposition respectively account for 24% and 5% of the exported nitrogen. The model allowed the estimation of the contribution of each source to nitrogen emissions and the nitrogen retention in soils and waters as influenced by basin factors. [ABSTRACT FROM AUTHOR]

• In EU nutrient pollution harms aquatic ecosystems condition and their services. • Current nutrient load to European seas is 3.3–4.1 TgN/y and 0.26–0.30 TgP/y. • EU policy measures could decrease the nutrient export to the seas −14% N and −20% P. • Widening the nutrient imbalance in coastal ecosystems, affecting eutrophication. • Further nutrient reductions could be possible by a combination of measures. Intensive agriculture and densely populated areas represent major sources of nutrient pollution for European inland and coastal waters, altering the aquatic ecosystems and affecting their capacity to provide ecosystem services and support economic activities. Ambitious water policies are in place in the European Union (EU) for protecting and restoring aquatic ecosystems under the Water Framework Directive and the Marine Strategy Framework Directive. This research quantified the current pressures of point and diffuse nitrogen and phosphorus emissions to European fresh and coastal waters (2005–2012), and analysed the effects of three policy scenarios of nutrient reduction: 1) the application of measures currently planned in the Rural Development Programmes and under the Urban Waste Water Treatment Directive (UWWTD); 2) the full implementation of the UWWTD and the absence of derogations in the Nitrates Directive; 3) high reduction of nutrient, using best technologies in wastewaters treatment and optimal fertilisation in agriculture. The results of the study show that for the period 2005–2012, the nitrogen load to European seas was 3.3–4.1 TgN/y and the phosphorus load was 0.26–0.30 TgP/y. Policy measures supporting technological improvements (third scenario) could decrease the nutrient export to the seas up to 14% for nitrogen and 20% for phosphorus, improving the ecological status of rivers and lakes, but widening the nutrient imbalance in coastal ecosystems (i.e. increasing nitrogen availability with respect to phosphorus), affecting eutrophication. Further nutrient reductions could be possible by a combination of measures especially in the agricultural sector. However, without tackling current agricultural production and consumption system, the reduction might not be sufficient for achieving the goals of EU water policy in some regions. The study analysed the expected changes and the source contribution in different European regional seas, and highlights the advantages of addressing the land-sea dynamics, checking the coherence of measures taken under different policies. [ABSTRACT FROM AUTHOR]