Indicator: Nitrate in groundwater

A graph shows the proportion of groundwater sampling sites where nitrate measurements for the years 2008 to 2014 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
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 per litre.
  • This threshold has been exceeded at around 18 % of sampling sites since 2008.
  • The EU Commission has initiated infringement proceedings against Germany.
  • 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).

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

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 groundwater in water treatment plants.

 

Assessing the development

The aim of the European Nitrates Directive (EU Directive 91/676/EWG) is to prevent the groundwater being polluted by nitrates. Governments are obliged to develop action plans to prevent nitrate concentrations above 50 mg/l. The EU Commission has initiated infringement proceedings against Germany because the directive has not be adequately implemented there. Since 2008 the proportion of sampling sites which exceed the threshold value has fluctuated between 17.5 and 19 %. The proportion of sampling sites with a nitrate concentration above 25 mg/l has also stagnated since 2008. Since 2016 meeting the nitrate limit has also become part of the German Sustainable Development Strategy (Federal Government 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. However, it is already foreseeable that they alone will not be sufficient to achieve the objectives of the Water Framework Directive and the Groundwater Directive. The effectiveness is essentially dependent on a reduction in the existing enforcement deficit. An improved control and sanctionability of violations of the regulatory law is urgently required.

 

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).