Despite legislation addressing nutrient pollution, the average nitrate concentration in EU groundwaters did not change significantly from 2000 to 2021. In addition, the number of groundwater monitoring stations with nitrate concentrations greater than 50mg/l, has not been reduced. Results from a high ambition model scenario show that potential nutrient load reductions are substantial, but still below the 2030 target. At this stage, it remains unlikely but uncertain whether the trend is sufficient to achieve EU obligations or the 50% nutrient loss reduction target.

Figure 1. Groundwater nitrate 2000-2021

Nutrients such as nitrogen, that are not taken up by plants, are lost to the environment and become pollutants when present in excessive amounts. This includes high levels of nitrate (NO3) in groundwater, which pose a threat to the environment and to human health. Reducing high levels of nitrate in groundwater has been a target of EU policy since the adoption of the Nitrates Directive. Mineral fertilisers and manure are the main sources of nitrate concentrations in EU groundwaters and an estimated 80% of the nitrogen discharge to the EU aquatic environment stems from agriculture. Around 30% of surface water and 80% of marine waters are eutrophic .

Several Directives address nitrogen losses to the environment. The Groundwater Directive and the Drinking Water Directive set the maximum allowable concentration for nitrate at 50mg NO3/l in order to protect human health and water resources.

The European Green Deal with its initiatives of the Zero pollution action plan , and the Biodiversity and Farm to Fork strategies , set a goal for the EU to reduce nutrient losses to the environment by 50%, by 2030. Such a reduction should result in lower groundwater nitrate concentrations and a reduced number of groundwater monitoring stations with nitrate concentration greater than 50mg/l, compared to the reference period 2012-2015 .

Despite legislation addressing nutrient pollution, the average nitrate (NO3) concentration in EU groundwaters did not change significantly from 2000 to 2021 - oscillating around 21mg NO3/l. In addition, data reported under the Nitrates Directive covering the period 2016-2019 shows, 14.1% of groundwater stations exceeded the maximum allowable concentration of 50mg NO3/l, which is comparable to 13.2% that was observed in the previous reporting period 2012-2015 .

An analysis, from the JRC (Joint Research Centre), modelled impacts in a high ambition scenario of improvements in domestic wastewater treatment, reduction of nutrient emissions to air, and with measures under the CAP 2023-2027 needed to achieve the Biodiversity Strategy and Farm to Fork targets. These measures, where especially the CAP measures are relevant for groundwater, could in combination reduce the nutrient load in European seas by 30% for nitrogen and 20% for phosphorous by 2030 (EC 2022). While these projected reductions are substantial, they are still below the target of 50% reduction overall in nutrient losses.

Figure 2. Nitrate in Groundwater - Nitrates Directive reporting period 7 (2016-2019)

EU Member States report groundwater nitrate concentrations under the Nitrates Directive. At country level, nitrate concentrations in groundwater for the period 2016-2019 are distributed into four classes (Figure 2). Class one represents groundwaters where concentrations are below 25mg/l, and at the other end of the scale, class four shows the share of stations that exceed the 50mg NO3/l maximum allowable concentration. In this reporting period, all EU-27 countries had some groundwaters with reported nitrate concentrations above the maximum allowable concentration of 50mg NO3/l (class four). The seven countries reporting more than 15% of their groundwaters exceeding this maximum level were Belgium, Cyprus, Germany, Luxemburg, Malta, Portugal, and Spain. In contrast, the seven countries with more than 80% of groundwaters below 25mg/l in class one were Croatia, Finland, Hungary, Ireland, Latvia, Poland and Sweden.