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You are here: Home / Data and maps / Indicators / Oxygen consuming substances in rivers / Oxygen consuming substances in rivers (CSI 019) - Assessment published Nov 2005

Oxygen consuming substances in rivers (CSI 019) - Assessment published Nov 2005

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Generic metadata

Topics:

Water Water (Primary topic)

Tags:
water | csi
DPSIR: State
Typology: Descriptive indicator (Type A - What is happening to the environment and to humans?)
Indicator codes
  • CSI 019
 
Contents
 

Key policy question: Is organic matter and ammonium pollution of rivers decreasing?

Key messages

Concentrations of organic matter and ammonium generally fell at 50% of stations on European rivers during the 1990s, reflecting improvements in wastewater treatment. However, there were increasing trends at 10% of the stations over the same period. Northern European rivers have the lowest concentrations of oxygen-consuming substances measured as biochemical oxygen demand (BOD) but concentrations are higher in rivers in some of the new EU Member States and Accession countries where wastewater treatment is not so advanced. Ammonium concentrations in many rivers in EU Member States and Accession countries are still far above background levels.

BOD and total ammonium concentrations in rivers between 1992 and 2002

Note: Number of river monitoring stations included in analysis noted in brackets

Data source:

Waterbase

Downloads and more info

Present concentration of BOD5, BOD7 (mg O2/l) in rivers

Note: Number of river monitoring stations included in analysis noted in brackets

Data source:

Waterbase

Downloads and more info

Present concentration of total ammonium (µg N/l) in rivers in European countries

Note: N/A

Data source:

Waterbase

Downloads and more info

Key assessment

There has been a decrease in BOD and ammonium concentrations in the old EU Member States, reflecting implementation of the Urban Waste Water Treatment Directive and consequently an increase in the levels of treatment of wastewater. BOD and ammonium concentrations also declined in the new EU Member States and Accession countries, as a result partly of improved wastewater treatment but also of economic recession resulting in a decline in polluting manufacturing industries. However, levels of BOD and ammonium are higher in the new EU Member States and Accession countries in which wastewater treatment is still less advanced than in the old EU Member States. Ammonium concentrations in many rivers are considerably higher than the background concentrations of around 15 mg N/l.

The decline in the level of BOD is evident in nearly all countries for which data are available (Figure 2). The steepest declines are observed in the countries with the highest levels of BOD at the beginning of the 1990s (i.e. the new EU Member States and Accession countries). However, some of these countries, such as Hungary, the Czech Republic and Bulgaria, although showing steep declines, still have the highest concentrations. There have also been dramatic decreases in the level of ammonium in some of the new EU Member States and Accession countries, such as Poland and Bulgaria (Figure 3). The new EU and Accession countries have a wide range of median concentration values, with Poland and Bulgaria above 300 mg N/l, but Latvia and Estonia below 100 mg N/l. Levels are generally still highest in the eastern and lowest in the northern European

In countries with a large proportion of its population connected to efficient sewage treatment plants, river concentrations of BOD and ammonia are low. Many of the new Member States still have a lower proportion of their population connected to treatment plants (see indicator CSI024), and when treatment is applied it is mainly primary or secondary. Concentrations in these countries are still high.

 

Data sources

More information about this indicator

See this indicator specification for more details.

Contacts and ownership

EEA Contact Info

Peter Kristensen

Ownership

EEA Management Plan

2010 (note: EEA internal system)

Dates

Frequency of updates

Updates are scheduled every 1 year in July-September (Q3)
Document Actions
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Comments

European Environment Agency (EEA)
Kongens Nytorv 6
1050 Copenhagen K
Denmark
Phone: +45 3336 7100