Nitrate in groundwater

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.

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.

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.

Supporting information

DefinitionMethodology

This indicator uses data reported under two different obligations. For the time series of average concentrations in figure 1 data from WISE SoE - Water quality (WISE-6) reporting obligation are used used (published in Waterbase – Water Quality ICM). For the country level assessment in figure 2 data from the Nitrates Directive reporting obligation are used.

For the time series in figure 1, annual mean concentrations are used as a basis in the analyses. Unless the country reports aggregated data, the aggregation to annual mean concentrations is done by the EEA. Automatic quality control procedures are applied both to the disaggregated and aggregated data, excluding data failing the tests from further analysis. In addition, a semi-manual procedure is applied, focusing on suspicious values having a major impact on the country time series and on the most recently reported data. This comprises:

Outliers
Consecutive values deviating strongly from the rest of the time series
Whole time series deviating strongly in level compared to other time series for that country and determinant
Where values for a specific year are consistently much higher or lower than the remaining values for that country and determinant.

Such values are removed from the analysis and checked with the country. For time series analyses, only complete series after inter/extrapolation are used. This is to ensure that the aggregated time series are consistent, i.e. include the same sites throughout.

Inter/extrapolations of gaps up to three years are allowed, i.e. to increase the number of available time series. At the beginning or end of the data series, missing values are replaced by the first or last value of the original data series, respectively. In the middle of the data series, missing values are linearly interpolated. The selected time series are aggregated to country and European level by averaging across all sites for each year.

For analysis of the present state on country level (figure 2), data reported under the Nitrates Directive for reporting period 2016-2019 are used, where data on monitoring station level are collected for each reporting period (four year period) and include characteristics on the water monitoring stations and values for the concentrations of NO₃ for each station. The data is summarised by country and by concentration classes. This information can also be viewed in the JRC exploratory dashboard for reporting period seven.

Policy/environmental relevance

The quality of freshwater, with respect to nutrient concentrations, is an objective of several directives: The Nitrates Directive (91/676/EEC), aimed at reducing nitrate pollution from agricultural land; the Urban Waste Water Treatment Directive (91/271/EEC), aimed at reducing pollution from sewage treatment works and certain industries; the Industrial Emissions Directive (2010/75/EU), aimed at reducing emissions from industry; the Water Framework Directive (2000/60/EC), which requires the achievement of good ecological status; the Groundwater Directive (2006/118/EC) on the protection of groundwater against pollution and deterioration. The Water Framework Directive also requires the reversal of significant and sustained upward trends in the concentrations of pollutants. Based on the Drinking Water Directive (2020/2184), the Nitrates Directive and the Groundwater Directive under the Water Framework Directive, set the maximum allowable concentration for nitrate at 50mg NO₃/l. This is to eliminate the need for expensive water treatment because it has been shown that drinking water in excess of the nitrate limit can result in adverse health effects (WHO 2003).

Reducing nutrient losses by 50% by 2030 is an important aspect of the European Green Deal initiatives: ‘Farm to Fork’ Strategy; Biodiversity strategy; Zero pollution action plan. The Common Agricultural Policy (CAP) is a key tool in this respect. The assessment of the 50% target is set out in the Annex to the Recommendations for the CAP Strategic Plans and is evaluated in the context of the Zero Pollution Monitoring Assessment published on 8 December 2022.

The 8th Environment Action Programme supports the objectives of the European Green Deal and forms the basis for the EU to achieve the Sustainable Development Goals of the United Nations.

The ‘nitrate in groundwater indicator’ is a headline indicator for monitoring progress towards the 8^th Environment Action Programme (8^th EAP). It mainly contributes to monitoring aspects of the 8^th EAP priority objective Article 2.2.d that shall be met by 2030: ‘pursuing zero pollution, including in relation to harmful chemicals, in order to achieve a toxic-free environment, including for air, water and soil, as well as in relation to light and noise pollution, and protecting the health and wellbeing of people, animals and ecosystems from environment-related risks and negative impacts’. The European Commission’s Communication on the 8^th EAP monitoring framework specifies that this indicator should monitor progress towards reducing nutrient losses by at least 50% in safe groundwater resources by 2030.

Accuracy and uncertainties

The indicator is meant to give a representative overview of nitrate conditions in the groundwaters of the European Union. This means it should reflect the variability in conditions over space and time. Countries are asked to provide data on groundwater bodies according to specified criteria.

The Waterbase - Water Quality ICM data for groundwater include almost all countries within the EU, while the Nitrates Directive data includes all EU countries. It is assumed that the data from each country represents the variability in space in their country. Likewise, it is assumed that the sampling frequency is sufficiently high to reflect variability in time. In practice, for Waterbase data, the representativeness will vary between countries, while for the Nitrates Directive data the coverage is more complete but reported at lower frequency.

Annual updates of Waterbase - Water Quality ICM data means that, due to changes in the database, the derived results of the assessment may vary in comparison to previous assessments. Database changes include changes in the QC procedure that excludes or re-includes individual sites or samples and retroactive reporting of data for past periods - which may re-introduce lost time series that were not used in the recent indicator assessments. Through communication with the reporting countries, the quality of the database can be, and incrementally is, further improved.

Data sources and providers

Metadata

DPSIRTopicsTagsTemporal coverageGeographic coverage

TypologyUN SDGsUnit of measureFrequency of dissemination

References and footnotes

EEA, 2022, 'Europe’s groundwater — a key resource under pressure’, European Environment Agency’', Briefing, European Environment Agency (
https://www.eea.europa.eu/publications/europes-groundwater).</div>

^↵
WHO, 2003, 'Nitrate and nitrite in drinking-water, Background document for development of WHO Guidelines for Drinking-water Quality (WHO/SDE/WSH/04.03/56)', (
https://cdn.who.int/media/docs/default-source/wash-documents/wash-chemicals/who-sde-wsh-04-03-56-eng.pdf?sfvrsn=e2fe0837_4).</div>

^↵
EC, 2021, REPORT FROM THE COMMISSION TO THE COUNCIL AND THE EUROPEAN PARLIAMENT on the implementation of Council Directive 91/676/EEC concerning the protection of waters against pollution caused by nitrates from agricultural sources based on Member State reports for the period 2016–2019, COM/2021/1000 final, European Commission.

^a^b
EU, 1991, Council Directive of 12 December 1991 concerning the protection of waters against pollution caused by nitrates from agricultural sources (91/676/EEC), 91/676/EEC.

^a^b
EU, 1991, Council Directive 91/271/EEC of 21 May 1991 concerning urban waste-water treatment, OJ L 135, 30.5.1991, p. 40–52 (ES, DA, DE, EL, EN, FR, IT, NL, PT).

^↵
EU, 2010, Directive 2010/75/EU of the European Parliament and of the Council of 24 November 2010 on industrial emissions (integrated pollution prevention and control) (recast) (Text with EEA relevance), OJ L 334, 17.12.2010, p. 17–119 (BG, ES, CS, DA, DE, ET, EL, EN, FR, IT, LV, LT, HU, MT, NL, PL, PT, RO, SK, SL, FI, SV).

^↵
EU, 2000, Directive 2000/60/EC of the European Parliament and of the Council of 23 October 2000 establishing a framework for Community action in the field of water policy, OJ L 327, 22.12.2000, p. 1–73 (ES, DA, DE, EL, EN, FR, IT, NL, PT, FI, SV).

^↵
EU, 2001, Directive 2001/81/EC of the European Parliament and of the Council of 23 October 2001 on national emission ceilings for certain atmospheric pollutants, OJ L 309, 27.11.2001, p. 22–30 (ES, DA, DE, EL, EN, FR, IT, NL, PT, FI, SV).

^↵
EC, 2014, Directive 2006/118/EC of the European Parliament and of the Council of 12 December 2006 on the protection of groundwater against pollution and deterioration

^↵
EU, 2020, Directive (EU) 2020/2184 of the European Parliament and of the Council of 16 December 2020 on the quality of water intended for human consumption (recast) (Text with EEA relevance, OJ L 435, 23.12.2020, p. 1–62 (BG, ES, CS, DA, DE, ET, EL, EN, FR, GA, HR, IT, LV, LT, HU, MT, NL, PL, PT, RO, SK, SL, FI, SV).

^↵
EC, 2019, Communication from the Commission to the European Parliament, the European Council, the Council, the European Economic and Social Committee and the Committee of the Regions ‘The European Green Deal’, COM(2019) 640 final,

^↵
EC, 2021, COMMUNICATION FROM THE COMMISSION TO THE EUROPEAN PARLIAMENT, THE COUNCIL, THE EUROPEAN ECONOMIC AND SOCIAL COMMITTEE AND THE COMMITTEE OF THE REGIONS Pathway to a Healthy Planet for All EU Action Plan: ‘Towards Zero Pollution for Air, Water and Soil’, COM/2021/400 final, European Commission.

^↵
EC, 2020, COMMUNICATION FROM THE COMMISSION TO THE EUROPEAN PARLIAMENT, THE COUNCIL, THE EUROPEAN ECONOMIC AND SOCIAL COMMITTEE AND THE COMMITTEE OF THE REGIONS A Farm to Fork Strategy for a fair, healthy and environmentally-friendly food system, COM/2020/381 final, European Commission.

^↵
EC, 2020, COMMUNICATION FROM THE COMMISSION TO THE EUROPEAN PARLIAMENT, THE COUNCIL, THE EUROPEAN ECONOMIC AND SOCIAL COMMITTEE AND THE COMMITTEE OF THE REGIONS EU Biodiversity Strategy for 2030 Bringing nature back into our lives, COM/2020/380 final, European Commission.

^↵
EC, 2020, COMMUNICATION FROM THE COMMISSION TO THE EUROPEAN PARLIAMENT, THE COUNCIL, THE EUROPEAN ECONOMIC AND SOCIAL COMMITTEE AND THE COMMITTEE OF THE REGIONS on the monitoring framework for the 8th Environment Action Programme: Measuring progress towards the attainment of the Programme’s 2030 and 2050 priority objectives, COM/2022/357 final, European Commission.

^↵
EC, 2020, ANNEXES to the COMMUNICATION FROM THE COMMISSION TO THE EUROPEAN PARLIAMENT, THE COUNCIL, THE EUROPEAN ECONOMIC AND SOCIAL COMMITTEE AND THE COMMITTEE OF THE REGIONS - Recommendations to the Member States as regards their strategic plan for the Common Agricultural Policy, COM(2020) 846 final, European Commission.

^a^b

Nitrate in groundwater

Figure 1. Groundwater nitrate 2000-2021

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

Supporting information

Metadata

References and footnotes