3.1 Pollution

To reach good ecological status of surface waters and good chemical status of surface waters and groundwater according to WFD, the reduction of water pollution is crucial and a main topic in water management.

A range of pollutants still reach European surface waters and groundwaters via different pathways with high impacts on water quality. Those pollutants are caused by diffuse sources of pollution and point sources of pollution. Whereas point sources have a specific discharge location, diffuse sources contain many smaller sources spread over a large area. This is also problematic due to the identification of specific drivers and causes of pollution. Point sources from urban waste water or industry can be easily address and managed; In contrast to diffuse pollution, where the measures may be more difficult to implement.

Point source pollution is mainly caused by urban inhabitants with discharges from waste water treatment plants. Over the past few decades, clear progress has been made in reducing emissions from point sources. The implementation of the Urban Waste Water Treatment Directive (UWWTD) and the Industrial Emissions Directive (IED), together with national legislation, has led to improvements in waste water treatment across much of the European countries.

Diffuse source pollution occurs mainly from agriculture, run off from urban areas, but also atmospheric deposition or non-connected dwellings. EU action on curbing diffuse nutrient pollution has a long history. Member States currently use a large number of measures, including farm-level nutrient planning, fertiliser standards, appropriate tillage, nitrogen fixing and catch crops, buffer strips and crop rotation.

Although recent decades have seen considerable success in reducing the number of pollutants discharged into Europe's waters, challenges remain in terms of urban and industrial waste water and diffuse pollution from agricultural sources. Once released into waters, pollutants can be transported downstream or through the aquifers (groundwater), and discharged into coastal waters.

The impacts of water pollution are diverse. Nutrients, like phosphorous or nitrogen, lead to eutrophication with algal blooms and oxygen depletion affecting fish and other aquatic communities. Pesticides or heavy metals harm the environment and human health. 

According to the 2nd RBMP of the WFD, 33 % of all surface water bodies in Europe are affected by diffuse source pollution, and nearly the same amount of groundwater area (34 %). Point source pollution affects 15 % of all surface water bodies, and 14 % of the groundwater area ([1]).

([1]) Source: https://www.eea.europa.eu/themes/water/european-waters/water-quality-and-water-assessment/water-assessments/pressures-and-impacts-of-water-bodies; download 17.06.2020

Key pressures from point source pollution and diffuse source are described in the following sections. Main pressures from point sources are waste water releases from households and industry. For diffuse sources, focus is on pressures from agriculture, nutrients and pesticides in particular. Other sectoral pressures with main impacts on aquatic ecosystems are non-connected dwellings and mining. These pressures are addressed in two separate sections.

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3.1.1        Point source pollution (urban waste water, industry)


Point source pollution to surface waters relates mostly to discharges from urban waste water including storm overflows, industrial sites or to a much lesser extent to aquaculture. Groundwater is mainly affected by leaching of hazardous substances from landfills and contaminated sites (EEA 2018b).

In Europe, point source pollution discharges have markedly decreased over the last decades caused by improved purification of urban waste water and reduced industrial discharges. Nevertheless, point source pollution still results in water pollution by oxygen consuming substances, nutrients, and hazardous substances with high impacts on aquatic ecosystems and human health. 

According to the 2nd RBMPs, 15 % of all surface water bodies are affected by point source pollution, from which two-thirds are assigned to urban waste water from treatment plants and some 20 % to industrial waste water ([2]). For groundwater, significant point source pressures are present in 14 % of the area mainly from contaminated sites, industrial sites, waste disposal sites, mining areas, and urban waste water (EEA 2018b).

More than 30 000 industrial and urban waste water facilities in Europe discharge more than 40 000 million m³ waste water every year (EC, n.d.; Van den Roovaart, et al., 2017). Three quarters of them treat water from urban sewage systems with a size of agglomeration of more than 2 000 population equivalents (EC 2019a). 90 % of the population in EU Member States are connected to sewage systems. The highest rates of above 80 % are located in Central and Northern Europe, where also the best level of treatment (e.g. nutrient removal) has been implemented in the majority of waste water treatment plants ([3]).

Waste water from industry has decreased over the last decade. This is caused by increased regulations (e.g. Industry Emissions Directive – IED or the European Pollutant Release and Transfer Register -  E-PRTR), improvements in treatment and implementation of best available techniques reference documents, e.g. BREF ([4]). Furthermore, relocation of various heavy polluting and energy intensive manufacturing industries outside Europe has also led to water quality improvement ([5]). The connection of industrial waste water to urban waste water treatment plants to avoid industrial emissions to water has marginally increased (EEA 2019a). Industries with still high direct releases to water are e.g. pulp and paper, steel, energy supply or chemicals, whereas manufacturing or food production tend to be more connected to urban waste water treatment plants (EEA 2019a). This is also due to the recommendation of the best available technique reference document for industrial installations (Canova, et al., 2018).

Also, storm water causes problems dependent on the sewer system. In case of heavy rains, overflows from combined sewer systems are discharged into surface waters with a mixture of rainwater and untreated waste water. This can lead to a temporally high pollution pressure.

([2]) Source: https://www.eea.europa.eu/themes/water/european-waters/water-quality-and-water-assessment/water-assessments/pressures-and-impacts-of-water-bodies; download 17.04.2020

([3]) Source: https://www.eea.europa.eu/data-and-maps/indicators/urban-waste-water-treatment/urban-waste-water-treatment-assessment-4

([4]) https://eippcb.jrc.ec.europa.eu/reference/

([5]) Source: https://www.eea.europa.eu/data-and-maps/indicators/industrial-pollution-in-europe-3/assessment

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Impacts from point source pollution to waters are caused by oxygen consuming substances, like ammonium or other substances, indicated by the measurement of the biochemical oxygen demand (BOD), nutrients such as phosphorus and nitrogen, hazardous substances, emerging pollutants, pathogens, like bacteria, viruses, or parasites, and microplastic particles.

The BOD shows how much dissolved oxygen is needed for microorganisms to decompose the organic matter. The resulting oxygen deficit in highly organic polluted waters causes impacts on aquatic communities, e.g. the loss of several macroinvertebrates and acute toxic impacts on fish.

Overall, concentrations of oxygen consuming substances (BOD, ammonium) and nutrients (nitrate and phosphate) have decreased over the last 25 years (Figure 3). It needs to be mentioned, that nitrate as well as phosphorus in rivers is not solely attributable to point sources of pollution. Those substances can also be released from diffuse sources. 

Figure 3             Trends in biochemical oxygen demand (BOD), ammonium, orthophosphate and nitrates in rivers

Notes: Insert notes here

Source: (EEA 2019b)

Hazardous substances are defined as toxic, persistent, and liable to bio-accumulate (Article 2, WFD). Some of the priority substances listed in Annex X of the WFD are defined as hazardous, for which all discharges, emissions and losses must be ceased within 20 years after adoption of cessation proposals by the European Parliament and the Council (WFD, Art. 16 (6)). Those substances are for example 4-Nonylphenol (surfactant) or pBDEs (flame retardants) used in many industrial productions.  Beside the risk of hazardous substances, emerging pollutants are present in low concentrations and include inter alia pharmaceuticals and personal care products, chemical degradation products, or endocrine‑disrupting compounds. The knowledge of long-term effects of these pollutants as well as the cocktail effect in waters is rather unknown (EEA 2018a).

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Measures and management challenges

Due to the successful implementation of the Urban Waste Water Treatment Directive (UWWTD), point source pollution pressure from urban waste water has significantly decreased. This is the result of the improved rate of population connected to sewage systems, but also the implementation of second (biodegradation) and third (nutrient removal) treatment levels all over Europe ([6]).

Measures to further reduce point source pollution from urban waste water but also industry include e.g. construction and adaptation, expansion, optimization of existing treatment plants, connection of households to sewer systems or consolidation and closure of non-effective treatment plants.

Improved efforts to retain chemicals in waste water treatment plants should go hand in hand with clear efforts to reduce them at source. Such measures can range from raising consumer awareness, to encouraging industries to adjust the composition of their products, to, over the longer term, fundamentally reviewing our use of chemicals and product design.

One example of source-based measures is the ban of phosphates in consumer detergents to avoid eutrophication in surface waters. The remaining allowed use of phosphates was legally fixed in Regulation 648/2004/EC (EU 2004). The European Parliament proposed a ban of the use of phosphates in consumer laundry detergents as of 30 June 2013 with similar restrictions to automatic dishwasher detergents for consumers as of 1 January 2017 ([7]).  

Furthermore, measures can be assigned to stricter requirements like lower targets for concentrations of specific pollutants in the discharged waste water by the responsible authority. This has been applied to protect drinking water resources of Lake Constance, the biggest lake in Germany. All treatment plants at the tributaries of the lake reduced markedly their phosphorous concentrations in the waste water discharge. Till today, Lake Constance is at good ecological status with drinking water quality (International Commission for water protection of Lake Constance (IGKB), 2014).

Even though considerable success has been achieved to reduce the discharge of pollutants from point sources, more emphasis is needed to protect water quality and human health. Despite varying conditions such as the density of population in European countries, or economic background, treatment has to be further improved in eastern parts of Europe in particular. A lower storm overflow is necessary with the help of nature-based solutions. To increase treatment, the implementation of the fourth treatment level is in progress. This level consists of innovative treatment techniques (e.g. oxidation with ozone, activated carbon filtration, membrane filtration) (UBA, 2014, EEA, 2019c). For example, by 2040, 100 of the 700 wastewater treatment plants in Switzerland will be equipped with a fourth purification level after decision in a plebiscite ([8]). The investment requirement of CHF 1.2 billion will be financed through a nationwide wastewater tax, which is a maximum of CHF 9 per inhabitant and year ([9]).

Furthermore, increasing energy costs, the reuse of high quality waste water and recycling of raw materials to circular economy as well as the consideration of climate change will be challenging tasks for the future (EEA, 2019).

([6]) Source: Source: https://www.eea.europa.eu/data-and-maps/daviz/changes-in-wastewater-treatment-in-8

([7]) Source: https://ec.europa.eu/commission/presscorner/detail/en/IP_11_1542

([8]) Source: https://www.vdi-nachrichten.com/technik/die-vierte-reinigungsstufe/

([9]) Source: https://www.vdi-nachrichten.com/technik/die-vierte-reinigungsstufe/

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3.1.2        Diffuse source pollution


In Europe, agriculture is the main diffuse source for water pollution with high emissions of nutrients, like nitrogen and phosphorus, as well as chemicals such as pesticides (EEA 2018b). Drivers for nutrient surpluses in soil and water pollution are excess use of fertilizer for crop production coming from mineral fertilizers and manure from livestock farming. Nutrients (as well as pesticides) enter the water cycle via erosion, surface run-off, leaching, or via inflow from polluted drainage and groundwater to surface waters with impacts to water quality, aquatic communities, and human health. In the second RBMPs, Member States identified that diffuse pollution from agriculture affects 22 % of surface water bodies and 30 % of the groundwater area leading to failure of good ecological and chemical status.

Nutrients are key for plant growth. In the EU, nitrogen surplus from agriculture is estimated to a total of approximately 27 million tons per year (Misselbrook et al., 2019), and since 2010, no improvement to reduce nitrogen surplus has been seen ([10]). Today, the highest total nitrogen surpluses occur generally, although not exclusively, in Western Europe.

Based on reported long-term data of nitrate in European waters, nitrate concentration in rivers showed a decreasing trend (Figure 3). The decline reflects the effects of improvements in waste water treatment, but also reductions of agricultural inputs. In contrast to rivers, nitrate concentration in groundwater does not show any trend during the last decades ([11]).

([10]) Source: https://www.eea.europa.eu/data-and-maps/indicators/agriculture-nitrogen-balance-1, download 16.04.2020

([11]) Source: https://www.eea.europa.eu/data-and-maps/indicators/nutrients-in-freshwater/nutrients-in-freshwater-assessment-published-9

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Pesticides are used to prevent or control any pest causing harm for agricultural products (FAO 2002). Pesticide sales data in Europe show, that in the time period 2011 to 2016, pesticide sales had an amount of 400 000 tonnes per year (EEA 2018c). Despite the high amount of pesticide sales, only 0.4 % of all surface water bodies and 6.5 % of groundwater area fail good chemical status based on exceedances of pesticide standards according to the status assessments in the 2nd RBMP (Mohaupt,, Völker,, Altenburger,, Birk,, Kirst,, Kühnel,, Semeradova, et al., 2020). Based on WISE – Waterbase reporting data for European surface water monitoring stations suggest that in the time period 2007 to 2017, 5–15 % showed exceedances by herbicides and 3–8 % by insecticides. For groundwater, the percentages were about 7 % for herbicides and below 1 % for insecticides. Exceedances of fungicides seemed to be less prevalent for both surface waters and groundwater (Mohaupt,, Völker,, Altenburger,, Birk,, Kirst,, Kühnel,, Küster, et al., 2020). Atmospheric deposition plays a role as a diffuse source for water pollution with chemicals, such as mercury and polycyclic aromatic hydrocarbons (PAH). PAH emissions occur during all combustion processes involving organic materials such as wood, coal, or oil. Mercury is released into the atmosphere, mainly by coal combustion, spreading over great distances and wash-out with rain to soil and waters (BMU/UBA, 2016). It can lead to accumulation in biota, especially fish, which is a risk for fish-eating animals and a potential risk for human health, e.g. (Zupo, et al., 2019). In Europe, mercury from atmospheric deposition is the main reason for failing good chemical status in more than 30 % of all surface water bodies (EEA 2018b)).

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Nutrients and pesticides releases as well as sediment run-off from agriculture have high impacts on surface waters and groundwater. The presence of too many nutrients leads to eutrophication with high levels of algae and aquatic plant growth in surface. Algae blooms also reduce transparency and lead to a lack of oxygen with a high risk for fish and other aquatic communities. In lakes, high nutrient concentrations can induce potentially toxic blue-green algae proliferation, that can be detrimental to human health. Coastal water bodies show similar reactions to excessive nutrient inputs (Ibisch et al., 2016).

Figure 4             Toxic blue-green algae bloom in a dam in Germany

Photo not included

Source: © J. Völker

Elevated groundwater nitrate concentrations are affecting raw water for drinking water and thus create a risk to human health. Groundwater containing nitrates can also be emitted into surface water bodies that are fed by groundwater (BMU/UBA, 2016).

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Pesticides input from diffuse sources can have impacts to aquatic communities, if they are directly exposed to pesticides inflow from farmland via erosion or indirectly through trophic chain (Hasenbein, et al., 2016; Maksymiv, 2015). Pesticides can also threaten human health, if contaminated surface waters or groundwater are used for drinking water supply. Furthermore, aquatic communities are exposed to mixtures of different pesticide substances. The knowledge on their combined effects of these mixtures to the aquatic environment is rare (Mohaupt,, Völker,, Altenburger,, Birk,, Kirst,, Kühnel,, Semeradova, et al., 2020). 

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Sediment run-off from agricultural fields can result in accumulation of fine sediments (see Box 2 in section 3.2), which overlay the natural riverbed resulting in the loss of habitats, e.g. spawning ground for trout and salmon ([12]). 

([12]) Source: https://www.eea.europa.eu/archived/archived-content-water-topic/water-pollution/diffuse-sources

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Measures and management challenges 

Member States are implementing different kinds of measures to reduce nutrient pollution from agriculture. Those measures include for example imposing restrictions on organic fertilizer application (e.g. in compliance with the Nitrates Directive to 170 kg N/ha at farm level), or restrictions in the application conditions for mineral and organic fertilizer and the amount of application of certain types of fertilizer during specific periods (e.g. no spreading of manure during winter). For this, some Member States have limited the total applicable nitrogen for all crops, to inform farmers about their obligation and to facilitate progress in the implementation of the Nitrates Directive (EC 2019e). To further improve efficient nutrient use, the EU Farm to Fork Strategy includes integrated nutrient management action plans to tackle nutrient pollution at source, and to reduce pollution from fertilizer by 50% and their use by 20 % (EC, 2020c).

Further strategies to reduce diffuse nutrient pollution are extensification and expanding the scope of organic farming, the use of precision farming with new digital technologies and innovative monitoring concepts (e.g. remote sensing) as well as the reduction of livestock density. Technical measures include catch cropping, the use of ground coverings and of tillage methods, establishing buffer strips with strict use restrictions, or increase manure storage capacity at farm level. Manure storage can improve the timing of application to minimise the risk of excessive leaching into the water environment. Advisory services should lead to better informed farmers with concrete and relevant information and increase the acceptance to implement measures.  

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To reduce pesticide pollution, relevant measures include for example minimising the risk of off- site pollution caused by spray drift, drain-flow and run-off, or reducing or eliminating applications along infrastructure close to surface water or groundwater. Other measures comprise the preference to use pesticides that are not classified as dangerous for the aquatic environment, the establishment of untreated buffer zones, or ban, or restriction in the use of pesticides. Some European countries (Denmark, France, the UK and Sweden) use reduction targets and timelines within National Pesticide Action Plans for a stepwise reduction of pesticides (EC and Directorate-General for Health and Food Safety, 2017).

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Even though water quality has improved over the last decades, pollution from diffuse sources in particular agriculture still remains a severe water management problem in Europe and a major cause for failing good ecological and chemical status of surface waters and groundwater under the WFD. To protect water ecosystems, there will be a need to strengthen the implementation of agricultural measures (both basic and supplementary) and a need for further efforts to adapt measures to regional pressures (EC 2019e). Specific implementation challenges also remain in addressing water quality issues in 'hotspots' with high nutrient loads as a result of farming, via better coordination of national/regional sectoral administrations (e.g. agriculture, water), and balanced fertilizers application (EC, 2017b). Simultaneously, adaption of financing instruments is necessary within the reform of the CAP. Still, basic measures need to be more strictly implemented to fully comply with the Nitrates Directive (EEA 2018b,  2019b).

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Box 1 Non-connected dwellings

Non-connected dwellings is a diffuse source pollution pressure caused by discharge from households not connected to urban waste water treatment plants or other collection systems ([1]).

In 2017, 11 % of the European population (approximately 50 million people), were not connected to waste water collection systems with the highest shares located in the Eastern part of Europe ([2]). Based on the 2nd RBMP, 21 WFD countries reported significant diffuse source pollution pressures caused by discharges not connected to sewage systems in 10 % of all surface water bodies. Furthermore, about 7.5 % of all groundwater area is affected by this pressure ([3]).

If the waste water is not properly treated by the installation and maintenance of individual appropriate systems, discharges of untreated waste water to waters can lead to nutrient input, or load of disease-causing organisms with potentially human health risks in e.g. bathing waters ([4]).

Measures to reduce water pollution are mainly technical and include inter alia waste water package plants, sand filters, drain fields, seepage pits or constructed wetlands with varying purification efficiencies (Vorne, Virpi et al., 2019). Furthermore, national regulatory frameworks have been elaborated to require the installation of appropriate treatment systems, e.g. in Bulgaria, which requires that the water is collected and treated within watertight cesspools (Grebot, et al., 2019). However, the installation of treatment systems, monitoring and maintenance are mainly in responsibility of the homeowners, and technical or financial support by local, regional, or national authorities is rather rare. This makes it difficult to enforce those treatment techniques in single houses or very small agglomerations.

There is still a huge knowledge gap on the impacts of discharges from non-connected dwellings, because neither the UWWTD nor the WFD directly regulate mitigation measures, and reporting obligations solely address connected dwellings with more than 2 000 population equivalents. This hinder information and conclusions on the implementation and use on the effectiveness of individual technical treatment systems. There is a need to further improve the knowledge on this issue, the adaption and harmonization of both WFD and UWWTD measures and reporting, further financial support for homeowners, and control of implemented techniques (EC 2019a; Grebot, et al., 2019).    

([1]) Source: https://www.eea.europa.eu/archived/archived-content-water-topic/wise-help-centre/glossary-definitions/scattered-dwellings, modified.

([2]) Source: https://ec.europa.eu/eurostat/tgm/table.do?tab=table&init=1&language=en&pcode=ten00020&plugin=1

([3]) Source: https://www.eea.europa.eu/data-and-maps/dashboards/wise-wfd, 30.03.2020

([4]) Source: https://www.eea.europa.eu/themes/water/european-waters/water-use-and-environmental-pressures/uwwtd/urban-waste-water-treatment

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3.1.3        Mining


Mining has been undertaken in Europe for many hundreds of years. Today many mines have been closed but both recent and abandoned mines still affect the quantitative, chemical and ecological quality of water. This section covers both mining and extraction (gravel, peat) activities.  Main pressures and impacts include acidification caused by lowering pH and discharge of heavy metals, other chemical pollution or pollution resulting by saltwater intrusion, alteration in flow, or lowering water table caused by an excessive dewatering during mine operation or after mining activities have stopped. Recovery of affected aquatic ecosystems – including groundwater - may take decades.

In the 2nd RBMP, 17 WFD countries reported mining as significant point and/or diffuse source pressure, affecting ca. 1 100 surface water bodies (less than 1 % out of all surface water bodies), and 7.5 % of the whole groundwater area. Countries with high shares of reported pressures from mining included the UK, Norway, Germany, Hungary, Bulgaria, Spain, and Italy.

Other analyses of mining pressures and their potential risks to water show a slightly different picture due to the use of other sources of data. In Figure 5 below, countries are scored based on mining activities (existing and abandoned mines) and Czechia, France, Germany, Poland, Romania, Sweden, Spain and United Kingdom are the Member States with the highest potential risk of mining pressures (WRc, 2012).

Figure 5             Potential risk of specific mining activities in European river basin districts

Notes: Map produces by CENIA, CR on behalf of European Commission ©; DG Environment, September 2012.

Source: WRc ( 2012)

Mining activities include the extraction of coal and lignite, minerals mainly potassium, rock salt and magnesium-containing minerals, clay, peat, metals such as copper and gold as well as stones, gravel, or sand (aggregates). It is estimated that in EU more than 32 000 sites with mining activities exist, of which more than 25 000 are used for the extraction of aggregates, with the highest numbers of sites in Poland and Germany. The number of peat extraction is some 1 400 sites of which 75 % is located in Finland (EU, 2018).

On the number of abandoned mines, European-wide data are rare, e.g. (EC, 2017a), and the number of abandoned mines is likely to be much higher than of active ones based on available data on certain countries, like Slovakia and Hungary. Slovakia has registered more than 17 000 and Hungary has reported some 6 000 abandoned mining sites (UNCCD, 2000). The bulk of mine water problems in Europe are in fact associated with abandoned mining sites and in numerous catchments, the single greatest cause of freshwater pollution is pollution from abandoned mines (ERMITE-Consortium et al., 2004).

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Main impacts to aquatic ecosystems are changes in surface and groundwater hydrology, sediment load, water quality, acidification and alteration in stream habitat and morphology (Figure 6).

Figure 6             Impacts of mining activities on water

Notes: Insert notes here

Source: http://ubclfs-wmc.landfood.ubc.ca/webapp/WID/course/land-use-impacts-on-water-3/mining-impacts-16/ .

All types of mining have the potential to directly disrupt groundwater hydrology, which in turn can affect surface waters that are in hydraulic continuity with the affected groundwater systems (ERMITE-Consortium et al., 2004). This is mainly due to dewatering resulting in a depression of the water table around the dewatered zone.

The water quality of mining activities is mainly affected by acidification or salinization. The acid runoff further dissolves heavy metals such as copper, lead, mercury into groundwater or surface water. Problems that can be associated with mine drainage include iron hydroxide precipitation during oxygenation of mining water, contaminated drinking water (e.g. with metals or sulphate), impacts on aquatic plants and animals, or the corroding effects of the acid on parts of infrastructures ([1]). Salinization is caused by the extraction of salts, e.g. potassium. High salt content altered aquatic communities and salt intrusion into the groundwater can endanger the quality of drinking water.

Placer mining or gravel extraction, and lead to increased sediment loading and decrease water clarity. Furthermore, hydromorphology is impacted by replacing coarse substrates such as gravels and boulders resulting in fewer invertebrate species.

Impacts of the removal of peat are increased sedimentation, increasing dissolved organic carbon (DOC) and phosphorus concentration, and decreasing pH values in the receiving waters (Lundin, et al., 2017; Ramchunder, et al., 2012). The leaching of phosphorus and nitrogen causes eutrophication problems into the watercourses or lakes and the load of solid peat particles causes silting of downstream water bodies.

Hydraulic fracturing to extract shale oil or shale gas potentially threatens drinking water resources (mainly groundwater) with the contamination with chemicals used in the hydraulic fracturing process. Surface water contamination can occur if the wastewater, containing the chemical additives as well as saline water and naturally occurring heavy metals and radioactive materials from the shale formations, is not properly managed and treated (Umweltbundesamt, 2012). Based on the shale gas information platform by EC, the UK is the only country in Europe, where companies pursue hydraulic fracturing (which is haltered since 2019)([2]), whereas a ban in France and Bulgaria and tests in Poland occur ([3]). In Estonia, mines cover ca. 1 % of the whole territory and about 16 million tonnes of shale oil were extracted in 2012 with high impacts on waters ([4]).  

Mining accidents can have tremendous impacts to the aquatic environment, for example the spill of cyanide rich waste water in Baia Mare, Romania in 2000. After a dam brake in the retreatment plant of gold mining company, large number of fish were killed in the Somes River, and also Tisza River and Danube. Furthermore, drinking water resources were contaminated (UNEP/OCHA, 2000).   

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Measures and management challenges

Measures to reduce pressures from mining activities for surface waters include re-use or recycling of excess water, diversion of run-off systems, or the use of reagents or chemicals with a low environmental impact, drainage systems, removal of suspended solids or liquid particles, or removal of dissolved substances by e.g. adsorption or nanofiltration. For groundwater, physical barriers, drainage systems techniques, or covering techniques are listed as effective measures to protect aquatic ecosystems (EU, 2018). These measures are part of the BAT (best available techniques) for the management of waste from extractive industries, which need to be implemented in EU Member States targeted by the Extractive Waste Directive (EWD) (2006/21/EC). According to Article 5 of the EWD, operators have to submit an extractive waste management plan (EWMP) as part of their permit applications.

After closure of mines, restoration is foreseen to rehabilitate impacts of former activities to soil and water. Many countries have national plans, like the rehabilitation for the Avoka river in Ireland ([5]) or  the Landscape Evaluation Tool for Open Pit Mine Design in Greece (Mavrommatis, and Menegaki, 2017). In Saxony, Germany, numerous post-mining lakes were created as part of the brown coal refurbishment. Most of these lakes are already being used for tourism purposes ([6]).  

Current mining activities are strongly regulated by Member States under National Laws. In most countries, Water Acts and Water Laws include protection of waters from mining activities. Additional legislations and regulations are implemented for the protection of groundwater, e.g. decree on activities that affect the quality of groundwater in Hungary or the Groundwater Exploration Act in Sweden (Endl, and Berger, 2016). The legislative instruments on international and national level regulating the current mining sector should ensure that the objectives of the Water Framework Directive (2000/60/EC) and Groundwater Directive (2006/118/EC) are achieved (WRc, 2012).

Measures under the WFD also aim at reducing water abstraction related to mining which is commonly used to control quantitative impacts from quarrying activities but could also be of use for deep mining (underground mining). Measures controlling substances are specific to individual substances, diffuse pollution or point source pollution. For example, to reduce diffuse discharge from saline waters into groundwater, K&S company in Germany covers the salt tailing piles and uses chemical transformation processes to treat the waste water. It is estimated, that this will reduce the proportion of saline wastewater by 20 % ([7]).

Data on implemented measures under the WFD and under the EWD are rare. In the context of the WFD, information on mining is part of different reporting obligations, e.g. WFD emissions inventory, pressures characterisation of water bodies or the failing of Environmental Quality Standards for e.g. heavy metals caused by mining activities for chemical (priority substances) or ecological status assessment (river basin specific pollutants). If mining activities cause significant pressures putting at risk the achievement of WFD objectives for surface water or groundwater, measures need to be included in the RBMPs. In the context of the EWD, mining operators have to draw up an extractive management plan (EWMP) as part of permit applications. Among other issues, EMWPs should cover the monitoring of surface and groundwater quantity and quality and the management of excavated material as well as mining waste (EC 2019f). Due to the relevance of both Directives to the assessment and management of water risks due to mining, a more synergistic way of gathering information and developing management strategies and measures for mining activities would be beneficial. 

[1] Source: https://www.usgs.gov/special-topic/water-science-school/science/mining-and-water-quality?qt-science_center_objects=0#qt-science_center_objects; 14.05.2019

([2]) Source: https://www.theguardian.com/environment/2019/nov/02/fracking-banned-in-uk-as-government-makes-major-u-turn

([3]) Source: https://ec.europa.eu/energy/topics/oil-gas-and-coal/shale-gas_en

([4]) Source:  https://www.academia.edu/4412537/Poster_of_Analyses_of_Estonian_oil_shale_resources

([5]) Source: http://www.mineralsireland.ie/MiningAndTheEnvironment/Rehabilitation.htm

([6]) Source: https://www.bergbau.sachsen.de/8193.html

([7]) Source: https://www.kpluss.com/en-us/sustainability/environment/water/

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