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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 Jan 2009

Oxygen consuming substances in rivers (CSI 019) - Assessment published Jan 2009

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Generic metadata

Topics:

Water Water (Primary topic)

Tags:
water | soer2010 | biodiversity | csi
DPSIR: State
Typology: Descriptive indicator (Type A - What is happening to the environment and to humans?)
Indicator codes
  • CSI 019
Dynamic
Temporal coverage:
1992-2006
Geographic coverage:
Albania Austria Belgium Bosnia and Herzegovina Bulgaria Croatia Cyprus Czech Republic Denmark Estonia Finland France Germany Greece Hungary Ireland Italy Latvia Liechtenstein Lithuania Luxembourg Macedonia (FYR) Montenegro Netherlands Norway Poland Portugal Romania Serbia Slovakia Slovenia Spain Sweden United Kingdom
 
Contents
 

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

Key messages

Concentrations of BOD and total ammonium have decreased in European rivers in the period 1992 to 2006, corresponding to the general improvement in wastewater treatment (Fig. 1).

 

EEA water quality indicators have up to now presented European and regional overviews and country comparison. However, water quality data at national level may not be relevant or sufficient for some countries, and EEA will in the coming years change its indicators to reflect concentration levels and trends at River Basin District (RBD) level to duly reflect local and regional differences in water quality.

See also WISE interactive maps: Mean annual BOD in rivers and Mean annual Total Ammonium in rivers

Biochemical Oxygen Demand (BOD5) and total ammonium concentrations in rivers between 1992 and 2006

Note: Between 1992 and 2006, BOD5 decreased from 5 to 2 mg O2/l

Data source:

Waterbase Version 7

Downloads and more info

BOD5 concentrations in rivers between 1992 and 2006 in different regions of Europe

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

Data source:

Waterbase (version 7)

Downloads and more info

Total ammonium concentrations in rivers between 1992 and 2006 in different regions of Europe

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

Data source:

Waterbase (version 7)

Downloads and more info

BOD5 concentrations in rivers between 2001 and 2006 in European countries

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

Data source:

Waterbase (version 7)

Downloads and more info

Total ammonium concentrations in rivers between 2001 and 2006 in European countries

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

Data source:

Waterbase (version 7)

Downloads and more info

Percentage of river stations per country with significant increasing, stable or decreasing BOD trend between 1992 and 2006

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

Data source:

Waterbase (version 7)

Downloads and more info

Percentage of river stations per country with significant increasing, stable or decreasing total ammonium trend between 1992 and 2006

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

Data source:

Waterbase (version 7)

Downloads and more info

Frequency distribution of concentration of BOD5 (mg O2/l) in rivers in European countries, 2006 or the latest year with available data

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

Data source:

Waterbase (version 7)

Downloads and more info

Frequency distribution of concentration of total ammonium (mg N/l) in rivers in European countries, 2006 or the latest year with available data

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

Data source:

Waterbase (version 7)

Downloads and more info

Key assessment

Introduction
Organic matter, measured as Biochemical Oxygen Demand (BOD) and ammonium, are key indicators of the oxygen content of water bodies. Concentrations of these determinands normally increase as a result of organic pollution caused by discharges from waste water treatment plants, industrial effluents and agricultural run-off. Severe organic pollution may lead to rapid de-oxygenation of river water, a high concentration of ammonia and the disappearance of fish and aquatic invertebrates.

The most important sources of organic waste load are: household wastewater; industries such as paper industries or food processing industries; and silage effluents and manure from agriculture. Increased industrial and agricultural production, coupled with a greater percentage of the population being connected to sewerage systems, initially resulted in increases in the discharge of organic waste into surface water in most European countries after the 1940s. Over the past 15 to 30 years, however, the biological treatment (secondary treatment) of waste water has increased, and organic discharges have consequently decreased throughout Europe. See also CSI 024: Urban waste water treatment.

Overall trend in BOD and ammonium (Fig. 1-3)
Concentrations of BOD and total ammonium have decreased in European rivers in the period 1992 to 2006, corresponding to the general improvement in wastewater treatment. The decrease is due mainly to improved sewage treatment resulting from the implementation of the Urban Wastewater Treatment Directive. The economic recession of the 1990s in central and eastern European countries also contributed to this fall, as there was a decline in heavily polluting manufacturing industries.

In European rivers, the oxygen demanding substances measured as BOD and total ammonium have decreased for 50 % and 60 % respectively from 1992 to 2006 (Figure 1).The decrease of BOD has been quite constant, whereas the decrease of total ammonium was larger in the first half of the period.

The largest decrease of BOD occurred in the western European rivers (Figure 2). From 2001 onwards, their concentrations have fallen below the stable concentrations of the northern European rivers (Finnish rivers, respectively). In the eastern European rivers, the concentrations have decreased for a third and reached the level that western European rivers already had in the middle 1990s. The concentrations in the southern European rivers have decreased for almost a third from 2000 to 2006 and become similar to the eastern European rivers concentrations. In the south-eastern European rivers, the decrease has been the lowest (around 20 % from 2000/2001 to 2006) resulting in the highest present concentrations.

The largest decrease of total ammonium (70 %) occurred in the western and eastern European rivers, due to high decrease before 1998, especially in the eastern European rivers (Figure 2). However, in 2006, the concentrations in the eastern European rivers were still 100 g N/l higher than the ones in the western European rivers, and the concentrations in the western European rivers were still more than 100 mg N/l higher than the ones in the northern European rivers with stable trend. In the south-eastern European rivers, the concentrations have decreased for a half from 2001 to 2006 and have fallen bellow the concentrations of the southern European rivers having the smallest decreae (one fourth from 2000 to 2006).

BOD and ammonium trend per country (Figure 4-5)
The largest declines in the level of BOD between 2001 and 2006 are observed in Slovenia, Spain, France, Bulgaria, Romania, Poland and Croatia (Figure 4). The decline is also evident in some central European countries (the Czech Republic, Hungary and Slovakia), Denmark and Italy. Austria, the United Kingdom, Belgium, Finland, Bosnia and Herzegovina, Serbia and the Baltic countries (Estonia, Lithuania and Latvia) have quite stable concentrations, which are among the lowest, except for Belgium, Lithuania and Serbia. FYR of Macedonia (FYROM) and Greece have fluctuating values. FYR of Macedonia (FYROM) also faces the highest concentrations. The concentrations have increased only in Albania.

The decline in the level of total ammonium between 2001 and 2006 is evident in south-eastern European countries (except Bosnia and Herzegovina), some central European countries (Slovenia, Poland, Hungary), Italy, the Netherlands and France (Figure 5). Among them, the largest declines are found in FYR of Macedonia (FYROM), Romania, Bulgaria and Albania. Quite stable and low concentrations are observed in the northern European (Norway, Finland, and Sweden) and western European countries (Austria, the United Kingdom, Denmark and Germany), the Baltic countries (Estonia, Lithuania and Latvia) and Bosnia and Herzegovina. Belgium and Spain, the first with the highest concentrations, face high fluctuations. Fluctuating concentrations are also evident in Greek rivers. Increase in total ammonium concentrations has occurred only in Luxembourg.

Stations with significant trend in BOD and ammonium concentration (Figure 6-7)
BOD and total ammonium concentrations have decreased at 39 % and 38 % of all stations on the European rivers between 1992 and 2006. Increasing trends in BOD and total ammonium have occurred only on 3 % and 2 % of all stations over the same period.

Most countries have decreasing BOD concentrations at more than 30 % of the stations. Countries having more than 39 % of the stations with significant downward trend come from western (5 countries), eastern (3 countries) and southern Europe (Spain). Luxembourg and Austria have the highest proportion of stations with downward trends in BOD (above 50 %).

In 40 % of the countries (8 out of 20 countries) there are no stations with significant upward trend in BOD concentrations (Fig. 6). In addition, half of the countries (6 out of 12) with significant upward trend face increasing BOD concentrations at less than 3 % of all stations. Only in Macedonia (FYROM), Latvia and Estonia, the proportion of stations with increasing BOD concentrations is more than 10 %.

Similar 43 % of the countries (9 out of 21 countries) have no stations with upward trend in total ammonium concentrations (Fig. 7). Only in Albania, Estonia and Macedonia (FYROM), the proportion of stations with increasing total ammonium concentrations is higher than 5 %, but less than 10 %. Countries having more than 38 % of the stations with significant downward trend come from western and eastern Europe (both 5 countries). Lithuania, Germany and Slovenia have the highest proportion of stations with downward trends in total ammonium (above 60 %).

BOD and ammonium levels per country (Figure 8-9)
See also WISE interactive maps: Mean annual BOD in rivers and Mean annual Total Ammonium in rivers

Slovenia, Ireland, Austria, Latvia and Spain have more than 60 % of all stations with the lowest BOD concentrations (class 1) (Fig. 8). Countries that have fifth or more of the stations with the highest BOD concentrations (class 5) are some south-eastern (FYR of Macedonia (FYROM), Bulgaria and Romania), central European (Hungary, Poland and the Czech Republic) and Benelux countries (Luxembourg and Belgium).

The Northern European (Norway, Finland and Sweden) and some western European countries (Lichtenstein, Ireland, Austria) have more than half of all stations with the lowest total ammonium concentrations (class 1) (Fig. 9). Countries that have more than fifth of the stations with the highest total ammonium concentrations (class 5) are Benelux countries (Belgium, the Netherlands, Luxembourg) and Poland, Bulgaria, Greece and Macedonia (FYROM).

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)
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Comments

European Environment Agency (EEA)
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Denmark
Phone: +45 3336 7100