7. Ecological status and water quality

7.     Ecological status and water quality

Water is a key resource for our quality of life, industrial and agricultural production as well as the condition of many ecosystems in Europe. The quality of water in Europe is influenced by direct and diffuse pollution from urban and rural settlements, industrial emissions as well as the agriculture sector. Due to the overall progress in the treatment of urban waste water, diffuse pollution from agriculture is now the single most important source of pollution, in particular nutrient pollution,  in Europe. Yet, despite the importance given to reducing pollution in recent environmental legislation, concentrations of pollutants in many European waters have remained high – illustrated by the results in the previous chapters that a large proportion of European water bodies are affected by pressures from diffuse and point source pollutants.

The status and pressure assessments in the previous chapters revealed that many European surface water bodies currently fail the Water Framework Directive’s objective. This raises the following questions:

  • What should be done to achieve good ecological status?
  • How can nutrient and pollutant input be reduced and water quality improved? And
  • How are the hydromorphological pressures lowered and the status of altered habitats improved?

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The Program of Measures (PoM) included in the RBMPs addresses these issues. The Program of Measures (PoM) describes the actions that must be taken to bring water bodies into “good status”, for which the key measures are as follows: reduced pollution emissions into water bodies by better wastewater treatment and implementation of good agricultural practice; and improving hydromorphology via restoration and changed land-use (e.g. buffer strips); ensuring minimum or environmental flows; removing migratory obstacles and transverse structures such as weirs so as to restore river continuity.

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Text box 8.1: Program of Measures

Article 11 of the WFD requires each Member state to establish a program of measures “for each river basin district, or for the part of an international river basin district within its territory,” and to implement such measures by 2012.  The effectiveness of PoM  is subject to review at six year intervals beginning in 2015.The WFD distinguishes between basic and supplementary measures (Annex VI Article11(2) and (3) of the Water Framework Directive). 

  • Basic measures, which comprise the minimum water body protection development requirements, are already defined in existing EU directives or serve to meet basic water management requirements (pursuant to Article 11(3) of the WFD), including those laid out in Directive 91/271/EEC concerning urban wastewater treatment, Directive 91/676/EEC relating to nitrate pollution, and Directive 80/778/EEC concerning drinking water.
  • Supplementary measures are necessary in cases where the basic measures are not sufficient to allow the WFD objectives to be reached. Such measures can include construction programs, rehabilitation projects, legislative, administrative and fiscal instruments, and educational projects.

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To protect freshwater from pollution, a comprehensive range of legislation has been established in Europe. The WFD has via the basic measures on compliance with the requirement of the Urban Waste Water Treatment Directive (UWWTD) and Nitrates Directive (ND) a clear target on reducing pollutants. Full implementation of these Directives will improve water quality and aid, although not necessarily guarantee, the achievement of good ecological status under the WFD.

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The European Commission, DG Environment, is currently examining the measures included in the RBMPs and evaluating if the PoMs set of for the different RBMPs are sufficient for achieving the objectives of the WFD. EEA are following this process and will in the fin al version of this report include results from CEC, DG Environments study on measures and PoMs.

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The sources of water pollution are extremely diverse and can vary considerably with geographical location. However, while landfills, forestry, mining, aquaculture and dwellings un-connected to a municipal sewage treatment works, for example, can all be of great importance locally, two broad sources alone contribute most to the freshwater pollution observed across Europe: urban wastewater and diffuse pollution from agriculture. In the current chapter the focus is on describing the effect of policies on reducing emissions to and improving water quality. The main focus is on illustrating the effect of Directive 91/271/EEC concerning urban wastewater treatment and Directive 91/676/EEC relating to nitrate pollution. These two Directives are import for achieving good water quality

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In a separate but parallel EEA thematic assessment on ecological status and hydromorphological pressures are status and pressures in relation to hydromorphology described and measures discussed. This assessment will also be further updated when results from DG Environment evaluations are ready.

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7.1.     Urban waste water and water quality (10 pp)

7.1.1.      Key messages

  • Pollutants in in many of Europe's surface waters have led to detrimental effects on aquatic ecosystems and the loss of freshwater flora and fauna.
  • Implementation of the Urban Waste Water Treatment Directive, together with comparable non-EU legislation, has led to improvements in wastewater treatment across much of the continent. This has resulted in reduced point discharges of nutrients and organic pollution to freshwater bodies.
  • Clear downward trends in water quality determinants related to urban and industrial wastewater are evident in most of Europe's surface waters, although these trends have levelled in recent years.

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Clean unpolluted water is also essential for our ecosystems. Plants and animals in freshwaters react to changes in their environment caused by changes in water quality. Many human activities results water pollutants with the main sources being discharge from urban waste water treatment and industrial effluents and losses from farming. Pollution takes many forms. Faecal contamination from sewage makes water aesthetically unpleasant and unsafe for recreational activities, such as swimming, boating or fishing. Many organic pollutants, including sewage effluent as well as farm and food-processing wastes consume oxygen, suffocating fish and other aquatic life.

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7.1.2.      Trend in urban wastewater treatment

During the last century increased population growth and increased wastewater production, coupled with a greater percentage of the population being connected to sewerage systems, initially resulted in most European countries in increases in the discharge of pollutants into surface water. Over the past 20 to 35 years, however, the biological treatment (secondary treatment) of waste water has increased, and organic discharges have consequently decreased throughout Europe. During the last 20 years tertiary (advanced/more stringent) treatment with nutrient removal (phosphorus and nitrogen) has been introduced at many waste water treatment plants resulting in markedly lower nutrient discharge to receiving waters.

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The Urban Waste Water Treatment has the objective to protect the environment from the adverse effects of discharges of urban waste water from settlement areas and biodegradable industrial waste water from the agro-food sector, by requiring Member States to ensure that such water is collected and adequately treated. Full implementation of the Directive is also a pre-requisite for meeting the environmental objectives set out in the EU Water Framework Directive as well as in the Marine Strategy Framework Directive.

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The UWWTD requires the collection and treatment of wastewater from all agglomerations of more than 2 000 people and its ongoing implementation has led to an increasing proportion of the EU's population being connected to a municipal treatment works via a sewer network (see Figure 7.1). Connection rates in northern Europe now exceed 80 % of the population while in central Europe the figure is above 95 %. Elsewhere in Europe, however, connection rates are lower, although in the case of the newer Member States this is explained by the later compliance dates agreed in the accession treaties.

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Figure 7.1 Changes in wastewater treatment in regions of Europe between 1990 and 2009

Notes: The numbers of countries are given in parentheses. Regional percentages have been weighted by country population.
N-North: Norway, Sweden, Finland and Iceland, only data up to 2006 available
C-Central: Austria, Denmark, England & Wales, Scotland, the Netherlands, Germany, Switzerland, Luxembourg and Ireland

S-Southern: Cyprus, Greece, France,  Malta, Spain  and Portugal (Greece only up to 1997 and then since 2007)
E-East: Czech Republic, Estonia, Hungary , Latvia, Lithuania, Poland, Slovenia, Slovakia (for Hungary and Latvia only data up to 2007 available)
South Eastern: Bulgaria , Romania and Turkey
The percentage values  have been weighted with country population when calculating the group values. Data on population connected to collecting systems without treatment available only since late 90-ies.

Source: CSI24/EEA-ETC/ICM based on data reported to OECD/EUROSTATJoint Questionnaire 2010 (July 2011 update)

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The UWWTD requires secondary biological wastewater treatment and, therefore, the substantial removal of both biodegradable and nutrient pollution. In addition, in catchments with waters designated as sensitive to eutrophication, the legislation demands more stringent tertiary treatment to remove much of the nutrient load from wastewater. Consequently, in addition to higher collection rates, the UWWTD has also driven improvements in the level of wastewater treatment over recent years.

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The majority of wastewater plants in northern and central Europe now apply tertiary treatment although elsewhere in the EU, particularly in the south-east, the proportion of primary and secondary treatment is higher (see Figure 7.1). While considerable progress has been made in implementing the UWWTD, excluding the longer compliance timelines for the newer Member State, full compliance is yet to be achieved, including the lack of more stringent tertiary treatment in some sensitive areas and inadequate treatment levels in wastewater treatment plants in some larger cities (Text box; EC, 2011).

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Text Box: Status of implementation of the Urban Waste Water Treatment Directive

In December 2011 published the 6th report on implementation of the UWWT Directive. The report covers the implementation of the Directive up to the reference year 2007/2008. Below is listed a summary of the key messages from the implementation report.


For the reference year 2007/2008, Member States reported 22,626 agglomerations (72% in EU-15 and 28% in EU-12) larger than 2,000 person equivalents (p.e.), generating a total pollution load of around 550 million p.e.

A breakdown taking into account the different size ranges shows that:

  • 2% of the agglomerations are larger than 150,000 p.e. (i.e. 586 big cities/big discharges), generating 43% of the pollution load (equivalent to around 248 million p.e.).
  • 32% of the agglomerations range between 10,000 and 150,000 p.e., generating 45% of the pollution load.
  • 66% of agglomerations range between 2,000 and 10,000 p.e., generating 12% of the pollution load.

Waste water collecting systems were in place for 99% of the total polluting load of EU-15 and for 65% of the total generated load of EU-12. Most EU-15 Member States had largely implemented this provision except for Italy and Greece which have 93% and 87% of generated load collected in collecting systems, respectively.

Secondary treatment was in place for 96% of the load for EU-15 and for 48% of the load for EU-12. As the infrastructure in place cannot always achieve quality standards in line with the Directive's requirements (possible reasons: inadequate capacity, performance or design etc.), 89% of the total generated load for EU-15 and 39% of the total generated load for EU-12 were reported to work adequately showing compliant monitoring results for secondary and more stringent treatment respectively.

More stringent treatment was in place for 89% of the load for EU-15 and for 27% of the generated load for EU-12. As the infrastructure in place cannot always achieve quality standards in line with the Directive's requirements (same reasons as for secondary treatment), 79% of the total generated load for EU-15 and 24% of the total generated load for EU-12 were reported to work adequately.

Figure 7.x: Average share of generated load collected in collecting systems, treated by secondary treatment and more stringent treatment for EU-15 (left) and EU-12 (right)

EU-15 refers to Member States which joined the EU before the 2004 enlargement: Austria, Belgium, Denmark, Germany, France, Finland, Greece, Ireland, Italy, Luxemburg, Portugal, Spain, Sweden, The Netherlands and United Kingdom (due to missing/late reporting UK is not included).

EU-12 refers to Member States who acceded to the EU in 2004 and 2007 enlargements: Czech Republic, Cyprus, Estonia, Hungary, Latvia, Lithuania, Malta, Poland, Slovakia, Slovenia, Bulgaria and Romania.


For 15 Member States (hereinafter referred to as EU-15) all deadlines in the Directive have expired. Therefore proper waste water collection and treatment has to be in place for all agglomerations within the scope of the Directive.

For the other EU Member States, (hereinafter referred to as EU-12), transitional periods were granted by their Accession Treaties. None of these transitional periods exceed the year 2015 except for some small agglomerations (less than 10,000 p.e.) in Romania, which have to comply by the end of 2018.

Source: CEC 2011: Commission Staff Working Paper - 6th Commission Summary on the Implementation of the Urban Waste Water Treatment Directive. Available at


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7.1.3.      Improved water quality

Implementation of the UWWTD has led to a reduction in the wastewater discharge of pollutants to receiving waters.  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. Clear downward trends in water quality determinants related to urban and industrial wastewater are evident in most of Europe's surface waters, although these trends have levelled in recent years.

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Organic matter, measured as Biochemical Oxygen Demand (BOD) and ammonium, are key indicators of the oxygen content of water bodies. 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. Mainly due to the implementation of secondary biological wastewater treatment under the UWWTD concentrations of BOD and total ammonium have decreased in European rivers in the period 1992 to 2009 (Fig. 7.2a). 

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The average concentrations of orthophosphate in European rivers halved over the past 20 years (Fig 7.2a). During the past few decades there has also been a gradual reduction in phosphorus concentrations in many European lakes (Fig 7.2a). Phosphorus levels have declined in recent years due primarily to improved wastewater treatment and bans on phosphates in detergents.

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Decrease in phosphate concentrate in European is less marked than for rivers, 80 % of the measurement stations show no change in phosphate concentrations. Significant decreases were observed at 13 % of stations in the Baltic, 28 % in the North Sea, and 5 % in the Mediterranean Sea (Figure 7.2b). In the Netherlands, phosphate concentrations showed a statistically significant decreasing trend at 15 of 20 stations. The improvements are attributed to implementation of urban wastewater treatment.

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The quality of EU bathing waters has improved significantly since 1990 — in 2010, (more than 90 %) of bathing areas complied with mandatory values (Fig 7.2c).

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The emission of some hazardous chemicals has also been reduced, as evidenced, for example, by a decline in the discharge of heavy metals from waste water treatment plants in the Netherlands (Fig. 7.2d) and to the River Seine (Meybeck et al., 2007).

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Figure 7.2 Changes in water quality variables related to improved wastewater treatment

A) Biochemical Oxygen Demand (BOD5), total ammonium orthophosphate concentrations in rivers and total phosphorus concentration in lakes between 1992 and 2009

B) Change in winter orthophosphate concentrations in coastal and open waters of the North East Atlantic, Baltic, Mediterranean and North Seas

Source: CSI19

Source: CSI21

C) Percentage bathing waters complying with mandatory  quality requirements, EU results based on more than 21 000 beaches

D) Emission of heavy metals from waste water treatment plants - Netherlands

Source: CSI22



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Compared to 10-15 years ago many countries and RBD now have low concentration of  BOD. River basins with the lowest BOD concentration (class 1: < 1.4 mg O2/l) are for example found in Ireland, Scotland, and Wales, in Denmark and southern Finland and in Austria and southern France. RBDs with the highest BOD concentrations (class 4&5: >= 3 mg O2/l) are found in Belgium, Bulgaria, and Romania.

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Countries with more than 50 % of all river stations with the lowest total ammonium concentrations (class 1: < 0.04 mg N/l) for 2009 or the latest reported year are Spain, Austria, Cyprus, Croatia, Sweden, Bosnia and Herzegovina, Ireland, Slovenia, Finland, the United Kingdom, Iceland, Liechtenstein and Norway. Countries with 20 % or more stations with the highest total ammonium concentrations (class 5: >= 0.4 mg N/l) are FYR of Macedonia, Greece, Romania, Bulgaria, Luxembourg, Albania and Belgium.

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Mean annual orthophosphate concentrations (PO4-P) exceed 0.2 mg/l in some river basins across Europe (see Figure 7.3C) and, whilst values vary with water body type, far lower concentrations are suggested as a threshold to prevent eutrophication (Dodds, 2006). Current concentrations in certain rivers therefore suggest that substantial improvements will be required for good ecological status to be achieved under the WFD.

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Figure 7.3 Annual average river concentration of BOD (mg O2/l), total ammonium and orthophosphate (mg/l as PO4-P) in 2008/09, by river basin district (BOD and PO4) or country (NH4)

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7.1.4.      Case studies: trend in water and biological quality

In Europe water quality has traditionally been measured and assessed using either basic physico-chemical (e.g. BOD, nutrients and oxygen level) or biological parameters or a combination of both – typically assessing organic pollution and eutrophication from point and diffuse sources. It is important to distinguish between water quality and ecological status or potential as the latter in addition to impact of pollution and water quality also include aspects such as hydromorphology and specific pollutants.

The previous section described major improvement on water quality over the last decades. This is also partly reflected in biological indicators related to water quality and pollution effects.  In many countries there have during the last 20 years been significant improvements in river water and biological quality (See the following examples from the Czech Republic and the improvement in the Rhine and the Elbe).

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Czech Republic

In the Czech Republic, for example, significant improvements in river water quality have occurred since the early 1990s based on a classification scheme incorporating indicators for BOD, nutrients and macro-invertebrate communities.

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Figure 7.4: A comparison of water quality in the rivers in the Czech Republic, 1991–1992 (left image) and 2007–2008 (right image)

Note: Blue: Unpolluted or slightly polluted waters; Green: polluted waters; Yellow: heavily polluted waters; and Red: Very heavily polluted waters

Methodology for the map: Traditionally, surface water quality is classified into 5 categories (shown in legend). The basic classification for the maps below is the aggregate of the following indicators: BOD5, CODCr, N-NH4+, N-NO3-, Ptotal and the saprobic index of macroinvertebrate communities (the final class is the worst class of these indicators).

Source: http://issar.cenia.cz/issar/page.php?id=1775/The T.G. Masaryk Water Research Institute

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Improved water quality in the Rhine and Elbe Rivers

Source: UBA 2010: Water resource management in Germany, part 1 fundamentals p. 54-57

The assessment of oxygen conditions in watercourses in Germany now occurs within the framework of ecological status monitoring. In the past, organic pressures were determined according to the Saprobic System, the results of which have been published every five years since 1975 by LAWA in the form of a biological water quality map. The Saprobic System uses macrozoobenthos (= invertebrates visible to the naked eye which live on or in the river bed) to describe the oxygen balance of a watercourse.

Observations of the biotic communities and oxygen balance in waterbodies have been recorded since at least the beginning of the last century. Figure 29 illustrates the conditions in the German sections of the Rhine and Elbe rivers. According to species lists from various authors, in the early 20th century the Rhine was inhabited by some 165 species of macrozoobenthos, while in around 1930 the Elbe was inhabited by around 120 species. As wastewater pollution increased and oxygen levels fell, the numbers of species have declined dramatically since the mid-1950s. The aquatic insect species (mayflies, stoneflies and caddis flies) have been particularly hard-hit by this development. By 1971, only 5 species out of a total of more than 100 remained in the Rhine, and in the Elbe only a few more. Improved oxygen conditions associated with the construction of industrial and municipal sewage treatment plants in the Rhine led to a turnaround from the mid-1970s onwards, while in the Elbe the situation did not improve until after German reunification in the early 1990s. Some of the characteristic river species that had been considered extinct or heavily decimated have now returned, but a large number of typical species remain absent, no doubt partly due to the fact that their habitats no longer exist due to structural impoverishment. Additionally, large numbers of non-native and ubiquitous species (species with a high degree of adaptability) which are better able to withstand anthropogenic

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Figure 7.5: Historical development of the biotic community and average oxygen levels of the River Rhine near Emmesrich and the Elbe near Magdeburg

Source:  Schöll, F. (2009a; 2009b)

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7.2.     Nutrient enrichment and diffuse source pollution

7.2.1.      Key messages

  • Despite improvements in some regions, diffuse pollution from agriculture remains a major cause of the poor water quality currently observed in parts of Europe. Agriculture contributes 50-80 % of the total nitrogen load observed in Europe’s freshwater.
  • Cost-effective measures to tackle both sources exist and can be implemented through the river basin management plans of the Water Framework Directive. Full compliance with the Nitrates Directive is also required.

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7.2.2.      European overview of diffuse nutrient pollution

In many catchments, runoff from agricultural land is the principal source of nitrogen pollution. In case of phosphorus, households and industry tend to be the most significant sources, although with reduced point source discharges, the diffuse loss from agricultural soils can also be significant.

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Modern-day agricultural practices often entail the high use of fertilisers and manure, leading to high nutrient surpluses that are transferred to water bodies through various processes. Here, excess nutrient affects the chemical status of water bodies and leads to eutrophication and changes in the ecological status. Important related environmental consequences include loss of plant and animal species, phytoplankton blooms and increased growth of macrophytes, with by-effects on the affected water bodies such as oxygen depletion, introduction of toxins or other compounds produced by the plants, reduced transparency and fish kills. Also, excess nutrient levels have negative impacts on the use of water for human consumption. Despite improvements in some regions, pollution from agriculture remains a major pressure on Europe's surface waters and groundwater.

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Nutrient application to agricultural land mainly result from artificial, mineral fertilizers and manure from livestock production, but also other sources such as biological fixation and atmospheric deposition are relevant.  In Europe, mineral fertilisers account for almost half of all nitrogen input into agricultural soils, while manure adds a further 40 % Today, the highest total fertiliser nutrient application rates — mineral and organic combined — generally, although not exclusively, occur in Western Europe. Ireland, England and Wales, the Netherlands, Belgium, Denmark, Luxembourg, north-western and southern Germany, the Brittany region of France and the Po valley in Italy all have high nutrient inputs (Grizzetti et al., 2007; Bouraoui et al., 2009). Inputs of nutrients to agricultural land across Europe are generally in excess of what is required by crops and grassland, resulting in nutrient surpluses (Grizzetti et al., 2007). The magnitude of these surpluses reflects the potential for detrimental impacts on the environment.

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Figure 7.6: Annual diffuse agricultural emissions of nitrogen to freshwater (kg nitrogen per hectare of total land area)

Source: Bouraoui, F, Grizzetti, B and Aloe, A. 2009. Nutrient discharge from rivers and seas JRC EUR 24002 EN, 72 pp

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7.2.3.      Nutrient concentrations and ecological effects in rivers, lakes and groundwater

The average nitrate concentration in European rivers has decreased slightly since 1992, reflecting improved wastewater treatment, reduced atmospheric inputs and, in some regions, lower agricultural emissions. This trend information is based on Eionet data reported to the EEA (rather than the mandatory information required under Directives).    

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Nitrate-concentrations in groundwater exceeded the compliance threshold of 50 mg l-1 under the Nitrates, Groundwater and Drinking Water Directives in ca. 10 % of reported stations over the 2001-2008 period. Most of these stations are located in western and southern regions. High NO3 concentrations in groundwater are found in particular in Spain, Belgium, Germany, Romania, Cyprus, Italy and Malta. The timeseries indicate increasing concentrations in the south-eastern region, possibly coupled to water scarcity and drought issues.

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Phosphate concentrations in European rivers have decreased over the last two decades, by more than 30% from > 0.15 mg l-1 in the early 90-ies to ca. 0.08 mg l-1 in 2008. Most of the decrease occurred in the 1990s, reflecting the general improvement in wastewater treatment and reduced phosphate content of detergents over this period. High concentrations (> 0.1 mg l-1 P) are found in several regions with high population densities and intensive agriculture, including southeast UK, part of the Netherlands, Belgium, Southern Italy, central Spain and Portugal, western Poland, Hungary, Bulgaria, Macedonia, northern Greece. Given that phosphorus concentrations greater than 0.1 mg l-1 P are sufficiently high to promote freshwater eutrophication, the observed high values in some regions of Europe are of particular concern.

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Total P in lakes has decreased only slightly since the early 1990s, and has been more or less stable since 2000. Lakes with high concentrations of total P (>0.05 mg l-1) are found mainly in RBDs in England, Belgium, the Netherlands, northern Germany, Poland, Hungary, Romania, Bulgaria, Spain, Portugal. Concentrations reported under Eionet generally exceed draft WFD targets (0.01-0-05 mg l-1) for many common lake types. Further reductions in diffuse emissions are needed to achieve WFD objectives.

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Impacts of eutrophication on freshwater ecology and human health:

There are major biological impacts demonstrated in the large river basins of Europe (Danube, Rhine, Po) due to excessive nutrient levels.

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For lakes there are reliable long-term trends for the Eastern and Western regions showing a decline in algal biomass up to the year 2000, but little change since then. For the northern region, no temporal trend is evident. The current chlorophyll levels are still too high to meet the WFD objective in most regions. As for total P, the WFD target for chlorophyll a is exceeded roughly by a factor of two for many common lake types.

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Figure 7.7 - Development of algal biomass (chlorophyll a concentrations) in European lakes aggregated to geographic regions for the period 1991-2006. Should be updated with SoE data until 2009.

Notes: Countries included in the regions are: East (EE, HU, LT, LV, PL, SI, SK); West (AT, BE, CH, DE, DK, FR, GB, IE, NL); North (FI, IS, SE); South (CY, IT, PT); South-East (BA, BG, HR, MK, RS, TR).

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Human health incidents involving toxic algal blooms (cyanotoxins) have been reported from at least 16 European countries. While no human deaths have been recorded, there are several instances of cattle, sheep and dog deaths, and numerous bird and fish kills have been ascribed to cyanotoxins after drinking untreated water. Hepatotoxic (liver) effects have been recorded more often than neurotoxic effects. WHO has developed guideline levels for cyanobacterial toxins in drinking water (Microcystin < 1 µg l-1) and bathing waters (Microcystin < 10 µg l-1).

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7.2.4.      Nutrient concentrations and ecological effects in transitional and coastal waters

Excess nutrients can create 'eutrophication', characterised by increased plant growth, problematic algal blooms, depletion of oxygen and loss of life in bottom waters and an undesirable disturbance to the balance of organisms present in the water.

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In spite of measures to reduce nutrient input, concentrations in European seas at 85 % of measurement stations show no change in nitrogen concentrations and 80 % show no change in phosphorous concentrations. Oxygen depletion is particularly serious in the Baltic and Black seas.

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Pollution of transitional, coastal and marine waters in many cases directly impacts the lower levels of the marine food-web: phytoplankton, zooplankton and animals living on the sea floor but impacts are moved upwards in the food chain with the many different feeding habits of marine organisms. In some cases severe pollution fundamentally alters ecosystem functioning.

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There are numerous pollutants impacting the marine environment, arising from many sources. These come from land-based activities such as agriculture, industry and wastewater treatment that emit or discharge pollutants to freshwater and, therefore, ultimately to coastal waters, whilst atmospheric deposition of certain pollutants to marine waters can also be a key source.

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Excessive use of the fertilizers nitrogen and phosphorous create eutrophication of marine waters which is the accelerated, enhanced growth of phytoplankton and higher plant forms and an undesirable disturbance of the balance of organisms in the water. Land-based sources of nutrients both diffuse sources — from artificial fertilisers used in agriculture and from animal manure — and point sources from urban wastewater treatment plants, whilst reducing, are still the main sources of nutrients to waterways. Nitrogen is also released into the atmosphere and later deposited on the sea surface. Where estimates are available, they show that approximately 25 % of the nitrogen load to the sea surface is contributed as atmospheric deposition (HELCOM, 2009a).

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Figure 7.8: Annual average river nitrate concentration (mg/l NO3-N) in 2008, averaged by river basin district

Note: This map shows the mean annual concentrations of Nitrate (NO3) as mg/l NO3-N measured at Eionet-Water River monitoring stations during 2008. All data are annual means.

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The EEA indicators on nitrogen, phosphorous and chlorophyll-a show the concentration levels of these substances and their change over time. Winter nutrient concentrations in transitional, coastal and marine waters respond to inputs from land and atmospheric sources. Algae are most abundant in the summer and their abundance is linked to the concentration of both the plant pigment chlorophyll-a in the water and nutrients. Based on the EEA indicators of nutrients (EEA, 2010d) and chlorophyll-a (EEA, 2010e) in transitional, coastal and marine waters (Maps 4.1, 4.2 and 4.3), there is clear evidence of nutrient enrichment:

  • within the coastal zones, bays and estuarine areas of some parts of the North East Atlantic region, particularly those near major European river deltas;
  • in the Baltic Proper and the Gulf of Finland as well as coastal areas of the Baltic Sea;
  • in areas close to river deltas or large urban agglomerations in the Mediterranean Sea;
  • in the Black Sea, although improvement has been significant since 1990 (Oguz et al., 2008).

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Figure 7.9: Nitrate (left panel) and chlorophyll a (right panel) in coastal waters

Source: EEA CSI21 and CSI23.

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In spite of measures to reduce nutrient concentrations in European seas, 85 % of measurement stations show no change in nitrogen concentrations, 80 % show no change in phosphorous concentrations (see Fig. 7.2b), and 89 % show no change in chlorophyll-a concentrations.

Winter oxidized nitrogen concentrations have fallen significantly at 21 % of 268 stations in the Baltic Sea and at 8 % of stations in the North Sea. The stations with decreasing trends are in Denmark, Finland, Germany, the Netherlands, Norway and Sweden, and in the open parts of the Baltic Sea (Figure 4.1). Little improvement is seen in other seas (EEA, 2010d).

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In 2008, the highest chlorophyll-a concentrations were observed in the Gulf of Riga, along the coast of Lithuania influenced by the Nemunas River, the Scheldt estuary in Belgium, and at the mouth of the Seine and Loire rivers in France (Map 4.3).

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7.3.     Relationship between ecological status and water quality

EEA have had first attempts to link the information reported on water quality in rivers and lakes via WISE-SoE to the information reported via the WISE-WFD reporting on status and pressures at water bodies.  Some preliminary results are presented in the following. These analysis will updated during the coming month be further enhanced will be distributed before the Eionet Stakeholder workshop ultimo March.

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River water bodies being classified as having high or good ecological status generally have much lower concentration of pollutants (BOD5, total ammonium, total phosphorus, and nitrate) and better water quality than WBs classified as having moderate to poor ecological status (Figure 7.10 and Figure 7.11).

  • River water bodies classified as having high ecological status also have generally low concentration of pollutants with nitrate, total phosphorus, and total ammonium being lower than 0.1 mg NO3-N/l, 0.02 mg P/l and 0.04 mg NH4-N/l..
  • There is a marked shift in water quality from water bodies having good ecological status or potential to water bodies having moderate of worse ecological status. Generally the water bodies with good status only have one-third of  the concentration levels of the water bodies in worse status.
  •  There is a general trend in increasing nutrient pollutant concentrations going from moderate to poor and bad ecological status or potential.

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The preliminary diagrams presented in figure 7.10 and 7.11 may indicate that in many rivers it is necessary to reduce the pollutant levels by 70 % to achieve the good ecological status objective of the WFD.

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Figure 7.10:  Comparison of mean annual average BOD and nutrient concentrations at river water bodies by ecological status or potential.

Note: Preliminary results based on 800-1000 river water bodies with annual average water quality concentration values (average of the years 2005 to 2009) compared with the ecological status/potential at water body level.

Based on results from 10 Member States.

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Figure 7.11: Concentration range (1st quartile, median and 3rd quartile) of annual average nutrient and organic matter pollutant concentrations in river water bodies in different classes of ecological status or potential (high to bad).


Note: Preliminary results based on 800-1000 river water bodies with annual average water quality concentration values (average of the years 2005 to 2009) compared with the ecological status/potential at water body level.

Based on results from 10 Member States.

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7.4.     Measures on point sources and diffuse sources

Section 7.4 has to be improved and updated and will be based on results from DG Environment evaluation of pressures and measures in the RBMPs.

To achieve the objectives of the WFD we need to manage pressures on the water environment by preventing increases that would cause deterioration of status and reducing those that are causing water bodies to be at less than good status. Reducing pressures in a sustainable way will enable the water environment to recover and place Europe and Member States in a better position to cope with the effects of climate change.

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7.4.1.      Key messages

  • EU water legislation, including the Water Framework Directive (WFD), Urban Waste Water Treatment Directive and Nitrates Directive, will help to improve the quality of freshwater (e.g. by reducing nutrient and chemical pollution) before it enters waters.
  • Wastewater treatment needs to continue to play a critical role in the protection of Europe's surface waters and investment will be required to upgrade wastewater treatment and to maintain infrastructure in many European countries.
  • While compliance with the UWWTD is already relatively high in the most of the northern and central European Member States, there is a need to improve both connection rates and treatment levels in other countries, to ensure improved water quality so the objectives of good ecological status are met.
  • Cost-effective measures exist to tackle agricultural pollution and need to be implemented through the WFD, while full compliance with the Nitrates Directive is also required.
  • The forthcoming reform of the Common Agricultural Policy provides an opportunity to further strengthen water protection.

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7.4.2.      Measures point sources

Continuing improvement in the level of pollutant removal from urban wastewater discharges is anticipated, driven by requirements under the UWWTD and non-EU legislation. While compliance with the UWWTD is already relatively high in the older Member States, country-specific deadlines for each of the newer Member States, established in the Accession Treaties, range between 2010 and 2018. As a consequence, improvements in both connection rates and treatment levels are likely to be realised for these countries over the coming years, provided that the directive is complied with.

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Wastewater treatment needs to continue to play a critical role in the protection of Europe's freshwater although significant investment will be required simply to maintain infrastructure in many European countries (OECD, 2009). Cohesion Policy funds can continue to make an important contribution through co-financing improvements to wastewater treatment (EC, 2009). The overall burden on the treatment process can, however, be reduced through a greater control of pollutants at source, an approach that is not only beneficial environmentally, particularly with respect to pollutants for which the treatment process was not specifically designed, but also in terms of cost-effectiveness (EEA, 2005a). Full-cost pricing for wastewater services will help drive controls at source.

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The possibilities for source control are varied and often specific to particular pollutants. The availability of alternative cleaning agents has enabled the use of phosphate-free industrial and domestic detergents, for example, significantly reducing phosphate levels received by wastewater treatment plants. A number of countries have either implemented legislation or established voluntary agreements with detergent manufacturers at the national level. Significant potential remains, however, for a greater use of phosphate-free detergents across many parts of Europe and the establishment of Europe-wide legislation in this respect would ensure that this potential is realised.

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Table 7.1. German catalogue of point source measures

Urban Waste Water treatment

Building and adapting urban WWT plants

Extension of urban WWT plants to reduce phosphorus or/and nitrogen input

Extension of urban WWT plants to reduce point source input of other pollutants

Optimizing the operational mode of urban WWT plants

Inter-municipal consolidation of WWT plant Building or rebuilding small WWT plants

Connecting the remaining non-connected areas to existing WWT plants Reducing point source pollution from other urban waste water sources

Combined WW and rainwater

Building and adapting facilities for diversion, treatment and retention of

combined WW and rainwater

Optimizing the operational mode of facilities for diversion, treatment and

retention of combined WW and rainwater

Other measures to reduce the input of pollutants from facilities for

diversion, treatment and retention of combined WW and rainwater

Industrial wastewater

Building and adapting industrial WWT plants

Optimizing the operational mode of industrial WWT plants

Reducing point source pollution from other industrial waste water sources

Other point sources

Reducing point source pollution from mining

Reducing thermal pollution

Reducing pollution from other point sources

Based on Kail and Wolter, 2011.

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7.4.3.      Measures (NiD etc.)

While clear improvements in the nutrient content of water over recent years are evident in some agricultural catchments across Europe, for others the situation is worsening or has stabilised but with concentrations at a high level. These findings reflect the fact that while some action has been taken in certain locations, compliance with the environmental objectives of the WFD is not required until 2015. Furthermore, appropriate measures under the ND have only recently been implemented in many countries and, in others, full compliance is yet to be achieved.

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Cost-effective measures exist to tackle agricultural pollution and need to be implemented through the WFD, while full compliance with the Nitrates Directive is also required. EU Member States have now established nitrate vulnerable zones one or more action programmes on their territory, with almost all such programmes incorporating the manure nitrogen application threshold of 170 kg/ha/year (EC, 2010). However, implementation of the ND is still incomplete and, even where full compliance has occurred, sufficient improvement in nitrate water quality will take some time because of transport processes in soils and groundwater.

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The achievement of good status in agricultural catchments will depend not only on the implementation of measures to address emissions of nitrogen, but also those of other pollutants, particularly phosphorus and pesticides. In this respect, the RBMPs of the WFD have a critical role to play in identifying cost-effective measures to tackle all sources of agricultural pollution. It is worth noting, however, that some national initiatives have already had clear positive impacts.

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Recent reforms of the Common Agricultural Policy (CAP) have resulted in a general decoupling of agricultural subsidies from production and the implementation of a cross compliance mechanism whereby farmers must comply with a set of statutory management requirements, including those that address the environment. There are options for a range of measures for the improvement of water quality, including improving manure storage, the use of cover crops, riparian buffer strips and wetland restoration. They also recognise the importance of educational and advisory programmes for farmers. Implementation of these CAP measures could play a key role in addressing diffuse pollution from agriculture. The forthcoming reform of the Common Agricultural Policy provides an opportunity to further strengthen water protection.

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Table 7.2. German catalogue of diffuse source measures

Agricultural nutrient and sediment input

Reducing the direct input of nutrients from agricultural activities

Developing buffer strips to reduce nutrient input

Other measures to reduce nutrient and sediment input from erosion

(agricultural areas)

Reducing nutrient leaching from agricultural areas

Reducing nutrient input from drainage

Reducing pesticide input from agricultural areas

Other diffuse sources

Reducing diffuse source pollution from mining

Reducing diffuse source pollution from contaminated sites

Reducing diffuse source pollution from paved areas

Measures in drinking water protection areas

Reducing pressures from acidification

Avoiding input from accidents

Reducing pressures from other diffuse sources

Based on Kail and Wolter, 2011.

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7.5.     Acidification

7.5.1.      Key messages

  • Acidification has been reported to affect 15% of lake WBs and 9% of river WBs in altogether nine Member States
  • Sweden, United Kingdom, Ireland, the Czech Republic and Belgium Flanders* are the member states that report the largest impact of acidification in rivers and lakes.
  • Acidification has been largely reduced over the past decades and biological recovery has started in most areas, although full recovery will not be achieved without further reductions in sulphate and nitrate deposition.

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7.5.2.      Assessment

More than 3500 river and 1650 lake water bodies have been reported as being affected by acidification in nine member states, accounting for 9 % and 15% of the river and lake WBs, respectively.

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Figure 7.12. Proportion of total number of classified lake and river water bodies reported to have significant impact from acidification.

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Sweden, United Kingdom, Ireland, the Czech Republic and Belgium (Flanders) have reported 6-17% of their river and lake WBs being affected by acidification. It is likely that the Belgium data represent erroneous reporting, and not antropogenic acidification (should be clarified by Belgian authorities).

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Focus on RBD with acidification problem – Is it possible for Sweden or other Member States having water bodies being affected by acidification to write a brief case on the affected RBDs and the impacts and measures?

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7.5.3.      Case studies

Trends in European acidification of surface water bodies

Source: Skjelkvåle, B.L., and de Wit, H. A. 2011

From 1990 to 2008 the concentrations of sulphate and nitrate in precipitation have decreased in large areas in Europe and North America due to emission reductions. The reductions were larger from 1990 to 1999 than from 1999 to 2008. The same pattern can also be seen for sulphate in surface water. Nitrate, in contrast to sulphate, does not show uniform decreasing trends despite the decrease in nitrogen deposition.

Biological recovery is under way in Europe, but full recovery is still far ahead.

The acidity of lakes and rivers has decreased due to the decrease in sulphate and many places there are good conditions for recovery of aquatic biological communities that have been damaged due to acidification (see figure 7.13).  Six countries (Czech Republic, Finland, Germany, Norway, Sweden and Switzerland) reported on biological recovery from national monitoring programmes. Most contributions focused on recovery of zoobenthos (small organisms that live on the bottom of rivers and lakes such as aquatic insects, worms and snails), but status of fish populations, algae and macrophytes (water plants) were also given. Zoobenthos have a short life cycle and are therefore able to respond more quickly to improved water chemistry than fish, which makes these organisms suitable as early indicators of biological recovery.

Almost all contributions reported evidence of biological recovery which was attributed to improved water quality, although other factors such as climate also contributed to explaining temporal variations. Higher species diversity was observed while species composition in many places has become more similar to non-acidified communities.

Full biological recovery is not documented anywhere. A return to pre-industrial biodiversity is unlikely in most cases, because original species are extinct, new species have been introduced and biological processes are often non-reversible. Several areas in Europe will never achieve good (non-acidified) water quality with current legislation of emissions of acidifying components. Future reductions of both S and N deposition are necessary to achieve biological recovery.

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Figure 7.12.  Number of sensitive benthic animals per sample and taxa richness of EPT taxa in the upper unlimed part of River Vikedal in the period 1993 - 2010. Fjellheim and Anker Halvorsen in chapter 4.5 of Skjelkvåle and de Wit 2011.

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Sweden Acidification varies between areas

Source:  SOER2010 Sweden Freshwater assessment


Acidification is caused by national and international anthropogenic loads. Acid fallout has decreased by more than 90 % during the past ten years. One source of acidifying pollutants that is becoming increasingly important is shipping. Differences within Sweden are large. This is clearly shown in the figure.

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Source:  Environment.no  - Acid rain http://www.environment.no/Topics/Air-pollution/Acid-rain/

A great deal has been done to reduce sulphur emissions in Norway and the rest of Europe, and pollution has been substantially reduced as a result. Nevertheless, much of the southern half of Norway is still suffering from damage caused by acid rain.

State Southern half of Norway still suffering from damage

Impact Acid rain kills fish

Driving forces Trends determined by energy use

Pressure Industry and transport the main sources

Response International agreements are vital

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Environment.no  - Acid rain http://www.environment.no/Topics/Air-pollution/Acid-rain/

Kail J. and C. Wolter, 2010 ‘Analysis and evaluation of large-scale river restoration planning in Germany to better link river research and management’, River Research and Applications

EEA SOER2010 Sweden Freshwater assessment


Meybeck 2007:

Schöll, F. (2009a): Rhein-Messprogramm Biologie 2006/2007, Teil II-D, Das Makrozoobenthos des Rheins 2006/2007, Bericht 172, 39 p. Publisher: IKSR

Schöll, F. (2009b): Elbe, Macroinvertebrates (Chapter in: Tockner, T. Uelinger, U. & Robinson, C.T. (publishers): Rivers of Europe. 700 p. Elsevier

Skjelkvåle, B.L., and de Wit, H. A. 2011. Trends in precipitation chemistry, surface water chemistry and aquatic biota in acidified areas in Europe and North America from 1990 to 2008. ICP Waters report 106/2011. 126 pp.  http://www.icp-waters.no/Publications/Reports/tabid/120/Default.aspx#d3

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