Nutrient conditions in European surface waters have improved in recent decades. The average nitrate and phosphate concentrations in rivers and total phosphorus concentration in lakes have decreased. The decrease in nutrient concentrations is likely related to improvements in wastewater treatment, the reduction of phosphorus in detergents and measures reducing agricultural inputs. There is a tendency for concentrations to level off in recent years, especially for rivers. There has been no overall decrease in the nitrate concentration in groundwater.

Figure 1. Nutrients in European water bodies

Nutrients in European water bodies

Nitrate in groundwater

The average nitrate concentration in European groundwater is fluctuating around the same level and there is no clear trend (Figure 1). The shorter, but more representative time series starting in 2000 follows the longer one closely. Agricultural activities, such as over-use of fertiliser, is the main driver for nitrate in groundwater.

Nitrate in rivers

The average nitrate concentration in European rivers decreased steadily over the period 1992-2009 but has levelled off since then. The shorter time series is parallel to the longer series, but the concentration level is lower. Agriculture remains the main contributor to nitrogen pollution, but the EU Nitrates Directive and national measures have contributed to lower concentrations. However, the apparent stabilisation in recent years calls for further measures.

See interactive chart for nitrate in groundwater and rivers here.

Phosphate in rivers

The average phosphate concentration in European rivers more than halved over the period 1992-2011. The marked decline is also evident for the shorter time series, but the average concentration is somewhat higher. From 2011 onwards the concentration levels off and increases in the last five years, indicating a need for further measures. The overall decrease in river phosphate can be related to measures introduced by national and European legislations, e.g. the Urban Waste Water Treatment Directive. Also, the change to phosphate-free detergents has contributed to lower phosphate concentrations.

Total phosphorus in lakes

There has been a gradual reduction in average total phosphorus concentration in European lakes since 1992, although the concentration settles from 2015. The concentration level is somewhat higher for the shorter, more representative time series. As the treatment of urban wastewater has improved, phosphorus from detergents has been reduced, and many wastewater outlets have been diverted away from lakes, phosphorus from point sources has become less significant. However, diffuse runoff from agricultural land continues to be a major phosphorus source in European lakes. Moreover, phosphorus stored in sediment can keep lake concentrations high despite a reduction in inputs.

See interactive chart for phosphorus in rivers and lakes here.

Figure 2. Status of nitrate in rivers in European countries

Rivers that drain land with intense agriculture or a high population density generally have the highest nitrate concentrations. In the period 2019-2021 (Figure 2), Lithuania had the largest proportion of river sites with average nitrate concentrations exceeding 5.6mgNO3-N/l (25%). Moreover, Belgium, Czechia, and Denmark had a high proportion (more than 35%) of sites with concentrations exceeding 3.6mgNO3-N/l.

There has been a significant decrease in river nitrate concentrations at 47% of the monitoring sites since 1992, and an increase at 12% of the sites. Czechia, Denmark, Germany and Slovakia had the highest proportion of significantly decreasing trends (82-100%). Spain and Switzerland had similar proportions of significantly increasing and decreasing trends, while Estonia and Lithuania had the highest proportion of significantly increasing trends (44% and 45%, respectively). An overall decline, although slowing in recent years, is observed for Belgium, Czechia, Denmark, Germany, Serbia and Sweden, contributing to the pattern seen in the European time series.