Indicator: Nitrate in groundwater

A graph shows the proportion of groundwater sampling sites where nitrate measurements for the years 2008 to 2018 were above 25 and 50 milligrammes per litre. In the period covered, neither sub-indicator has shown any significant change.Click to enlarge
Proportion of sampling sites which exceed the target value for nitrate in ground water
Source: German Environment Agency and the Länder Initiative on Core Indicators (LIKI) based on data from the German Working Group on water issues of the Federal States and the Federal Government Figure as PDF

Table of Contents

 

At a glance

  • The European Nitrates Directive places Germany under the obligation to prevent exceedances of the threshold of 50 milligrammes nitrate per litre.
  • Since 2008, the threshold has been exceeded every year at almost one in five measuring points.
  • On June 21, 2018, the European Court of Justice found Germany guilty of violating the EU Nitrates Directive (case C-543/16).
  • Agriculture is the most important source of high nitrate concentrations in groundwater.
 

Environmental importance

In agriculture crops are given the necessary nitrogen via fertiliser. However, the fertiliser is often not applied correctly for the specific site and use. If the amount of fertiliser is too high the plants do not absorb it completely. Excessive nitrogen is leached out and ends up as nitrate in the groundwater and other water bodies. This leads to eutrophication in rivers and lakes (cf. ‘Ecological status of rivers’ and ‘Ecological status of lakes’ indicators), and to nitrogen enrichment and exceedance of the nitrogen threshold in ground water.

Nitrate can be converted to nitrosamines in the human body. This can result in disruption to the oxygen transport in infants (methemoglobinemia). The Drinking Water Ordinance therefore stipulates a maximum value for nitrate of 50 milligrammes per litre (TrinkwV 2001).

The threshold is very rarely exceeded in drinking water (cf. drinking water quality, in German only). It is complex and expensive to remove nitrate from pipe water in water treatment plants.

 

Assessing the development

The aim of the European Nitrates Directive (EU Directive 91/676/EWG) is to prevent pollution of groundwater by agricultural nitrate inputs. Governments are obliged to develop action plans to prevent nitrate concentrations above 50 mg/l. On 21 June 2018, the European Court of Justice found Germany guilty of violating the EU Nitrates Directive. The reason therefore was that the directive had not been implemented adequately and the measures taken so far were not sufficient to achieve a significant reduction in nitrate pollution. Since 2008 the proportion of sampling sites which exceed the threshold value lies between 17 and 19 %. The proportion of sampling sites with a nitrate concentration above 25 mg/l has also stagnated since 2008 at 35-38 %. Since 2016 meeting the nitrate limit has also become part of the German Sustainable Development Strategy (BReg 2016).

The most important instrument for achieving the Nitrates Directive targets is the German Fertiliser Application Ordinance (DüV). This was revised in a long-term process by the Federal Government and adopted in spring 2017. The effects of this new regulation will only become apparent in a few years. As the EU Commission is of the opinion that these alone will not be sufficient to achieve the objectives of the Nitrates Directive, the Fertiliser Ordinance is currently being revised again and the revised version will enter into force by spring 2020.

 

Methodology

Germany has to send data on the condition of the groundwater to the European Environment Agency (EEA) on a regular basis. The Federal States therefore selected representative sampling sites to add to the EEA groundwater network. These are reported to the EEA through the German Environment Agency. The indicator compares the sampling sites where the limit value is exceeded with the total number of sampling sites.

More detailed information: 'Grundwasserbeschaffenheit' (in German only).