Sustainable development in Germany - 17 Goals to Transform our World

Water quality – Reduction of substance pollution in water

Indicator 6.1.b: Nitrate in groundwater

SDG-6.3.2
(Evaluation of the development of Germany in the reporting year 2018 as reporting year from indicator report 2021)

Selection

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This overview includes additional information on the indicators presented above, such as a brief definition of the indicator and a description of the politically determined target value, as well as the political intention for selecting the indicator.

Definition of indicators (Taken from the official translation of the German Sustainable Development Strategy)

The indicator shows the percentage of monitoring sites at which the annual average concentration of nitrate in groundwater does not exceed the threshold of 50 milligrams per litre.

Target and intention of the German Government (Taken from the official translation of the German Sustainable Development Strategy)

Groundwater is a key element of the ecosystem. It is part of the water cycle and performs important ecological functions. Groundwater is also Germany’s most important drinking water resource. However, elevated nitrate content impairs the ecology of bodies of water. The threshold of 50 mg/l of nitrate in groundwater specified in the Ground Water Ordinance and in the Surface Waters Ordinance are therefore to be observed at all monitoring sites by 2030.

Data state

The data published in the indicator report 2021 is as of 31.12.2020. The data shown on the DNS-Online-Platform is updated regularly, so that more current data may be available online than published in the indicator report 2021.

Last modification of code (data) 2021-02-15: see changes on GitHub opens in a new window
Last modification of code (text) 2021-09-10: see changes on GitHub opens in a new window

Taken from the official translation of the German Sustainable Development Strategy

The nitrate content in groundwater is collected by the Länder for the purpose of reporting on the status of groundwater in Germany to the European Environment Agency (EEA). The monitoring sites used for this purpose together form the so-called EEA monitoring network. The EEA monitoring network comprises a total of 1214 monitoring sites and provides a representative picture of Germany. The data are compiled by the Federal Environment Agency from information provided by the German Working Group on Water Issues of the Länder and the Federal Government (LAWA).

Like the indicator of phosphorus content in flowing waters, the nitrate indicator does not reveal how far above or below the threshold the readings have been. The indicator merely records how many of all the monitoring sites complied with the prescribed threshold. The nitrate load may have fallen sharply at some monitoring sites. Nevertheless, if the concentration remains above the maximum of 50 mg/l, the reduction will not be reflected in the indicator.

The same applies to nitrate loads that have increased but are still below the threshold. The interpretation must also take into account that measures to reduce nitrate pollution may have a delayed effect, since the period of infiltration from the surface to the groundwater can take several years.

The naturally occurring level of nitrate lies between 0 and 10 mg/l. Concentrations between 10 and 25 mg/l indicate minor to medium loads. Concentrations between 25 and 50 milligrams per liter indicate severe groundwater contamination. Figures above the threshold of 50 mg/l which is set in the Ground Water Ordinance and which also underlies this indicator mean that the groundwater has a poor chemical status and cannot be used as drinking water without treatment.

In 2018 the target of less than 50 mg of nitrate per litre was met at 82.7 of all monitoring sites. Since 2008, the percentage of monitoring sites at which this target is met has remained virtually unchanged. This means that the goal of recording concentrations below the threshold at all monitoring sites has not been achieved and that the indicator value is not recognisably moving in that direction. Conversely, in 2018 the nitrate threshold of 50 mg/l was exceeded at 17.3% of the groundwater monitoring sites in the EEA monitoring network. Consequently, the groundwater at these locations cannot be used for drinking-water supplies without treatment. At 17.3% of the monitoring sites the nitrate value lay between 25 and 50 mg/l, which still indicates an elevated degree of pollution. This percentage rate also remained virtually unchanged over the years.

The pollution of groundwater with nitrate is caused primarily by the leaching of nitrate from various nitrogen fertilisers. Besides farmyard manures such as liquid manure and slurry, these also include the mineral fertilisers that are used in intensive crop-farming. The last few years have also seen an increase in the use of digestate, which occurs as a by-product of biogas power plants, as an agricultural fertiliser. All of these things can contribute to higher nitrate values in groundwater if fertilisation is not matched to specific crop requirements. Accordingly, the development of indicator 2.1.a – Nitrogen surplus in agriculture – influences the nitrate load in groundwater.

In order to measure the actual influence of agricultural activity on the nitrate load of waters, there is a separate system of nitrate reporting to the EU. For this report, the monitoring sites for waters in predominantly agricultural catchment areas are selected from the EEA site network. The nitrate load in that specific part of the monitoring network is therefore above the average for indicator 6.1.b.

This summary table illustrates the evaluations of the indicator by status of previous years. This shows whether the weather symbol for an indicator has been stable or rather volatile in the past years. (Evaluations from the indicator report 2021)

Indicator

6.1.b Nitrate in groundwater

Target

Compliance with the nitrate threshold value of 50 mg/l at all monitoring points by 2030

Year

2015

2016

2017

2018

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Source 1

 German Environment Agency

Organisation

German Environment Agency

Data source Nitrate in groundwater opens in a new window

Source 2

 Länderinitiative Kernindikatoren

Organisation

Länderinitiative Kernindikatoren

Data source Nitrate in groundwater (only available in German) opens in a new window