Why should we care about this issue
With an available water supply of 188 billion m³ and water extraction of around 32 billion m³ Germany is a water-rich country. Water scarcity is not currently a problem, even though regional shortages caused by low groundwater supplies have to be compensated for by piping water from areas with a surplus. However, recent years have shown that not even Germany is immune to the effects of climate change, such as more frequent flooding and periods of drought.
Protecting groundwater from pollution has always been especially important in Germany because around 65.5 % of the country’s drinking water is taken directly from groundwater supplies. The main causes of chemical pollution in groundwater are high discharges of nitrogen and pesticides, often from agriculture, as well as point-source pollution from residual contamination and landfill sites.
One traditional problem is the high level of pollution of lakes and rivers with nutrients and other substances, and use-related hydro-morphological changes which threaten the natural functions of water-bodies. Nutrients encourage algal growth, which in turn has a number of negative effects on water-bodies. Heavy algal growth results in oxygen shortages that can kill fish. It also makes it more difficult to purify drinking water and can cause allergic reactions for bathers.
To assess the condition of the groundwater, surface and coastal waters, they are monitored regularly as part of national and international programmes. The monitoring programmes carried out by the Länder and the river-basin commissions record not only biological parameters but also chemical properties such as nutrients, heavy metals and organic micro-pollutants, as well as hydro-morphological characteristics following changes to the structure of water-bodies, for example because of shipping, hydroelectric power or flood protection.
The state and impacts
Material pollution of watercourses
Monitoring carried out by the German Working Group on Water Issues (LAWA, Länderarbeitsgemeinschaft Wasser) show that water pollution by substances such as organic environmental chemicals, heavy metals and nutrients has fallen by varying degrees in recent decades.
Adsorbable organically-bound halogens (AOX) and total nitrogen are seen as representative of the chemical pollution of Germany’s watercourses. These summary indicators are used mainly to record industrial pollution from point sources (AOX) and diffuse pollution from agriculture (total nitrogen). Total nitrogen is also a significant indicator of pollution of the oceans via rivers. However, it should be made clear that while both groups of substances are important for characterising water quality, they by no means cover all aspects of the state of the water. They also do not reflect the considerable negative impact on ecological water quality caused by man-made changes to the structure of water-bodies.
Between 1996 and 2007 there was a slight improvement in water quality as regards AOX, though with considerable fluctuations: the proportion of monitored watercourses meeting the Class II chemical water quality target of 25 µg/l rose from an average of 39 % for 1996-1998 to an average of 47 % for 2005-2007.
For total nitrogen the pollution levels were higher: an average of only 13 % of monitoring stations met the Class II water quality requirement for total nitrogen of 3 mg/l between 1996 and 2007. Since 1996 the annual achievement has ranged from 11 % of monitoring stations (1999, 2004, and 2006) to 16 % (1997), while the most recent figure (2007) was 14 %. This shows that in future water pollution controls will be particularly needed in areas with diffuse pollutant discharges, particularly from agriculture. Intensive fertilisation and excessive concentrations of livestock produce an average annual nitrogen surplus of some 105 kg per hectare. The distribution of water quality classes for total nitrogen at the same 133 monitoring stations for 1996-2007 has seen a slight reduction in monitoring stations with high levels of pollution (Class III and worse), thanks mainly to improvements in wastewater treatment by municipal treatment plants and industry.
Structural changes to watercourses
Only 21 % of Germany’s rivers and streams – most of them in less populated areas – are still in a near-natural condition, meaning that they have undergone little or only moderate levels of man-made change. A total of 33 000 km of watercourses were surveyed and classified into seven grades – from Class I = unchanged to Class 7 = completely changed – according to the system used by the LAWA. The major rivers have generally been fitted with defences and locks for shipping and hydroelectric power generation. Large areas of their floodplains have also been cut off from the rivers and narrowed by flood embankments. This explains their considerable structural problems and why the vast majority were classified as substantially to completely changed. The Ems, Danube, Oder and Weser are graded as Class 6 or 7 for 50 % of their length while the intensive use of the Rhine and its surrounding area means that as much as 80 % of its length from Lake Constance to the Netherlands also falls into these classes.
In contrast, between the Central Uplands (Mittelgebirge) and the Geesthacht weir, the Elbe has sections that are clearly still structure-rich (Classes 3 and 4). Only the Tidal Elbe and the more densely populated stretches along the Upper Elbe are structure-poor and thus graded in Classes 6 and 7. This underlines the fact that near-natural sections of the major rivers, such as the free-flowing section of the Danube below the confluence with the Isar and the middle section of the Elbe, are rare and worth protecting.
Most of the smaller rivers and streams in the Central Uplands, the hill country and the North German Plain have also been altered for hydroelectric power generation, to protect areas of settlement and transport routes or for agricultural use including land improvement. They are regularly maintained, which tends to prevent morpho-dynamic processes, in other words natural development. These water bodies are mostly classified as distinctly changed – Class 4 – to completely changed – Class 7.
Nitrate in groundwater
The Länder have set up theirs own individual monitoring networks to monitor groundwater quality. Nitrate levels are regularly tested at almost all the sites in the networks. For their regular reports to the European Environment Agency (EEA), the Länder chose representative sites and combined them to form what is known as the EEA groundwater monitoring network. The following chart gives an overview of nitrate pollution in the groundwater in 2007 based on the 683 sampling sites in this network where the groundwater nitrate content was determined.
Nitrate pollution depends to a large extent on land use in the catchment area of a station. Regional hydro-geological conditions such as depth to the water table and flow speed, as well as the underground hydro-chemical conditions, play an important role.
Concentrations are < 25 mg/l at 67.3 % of the stations. At 14.1%, however, the 50 mg/l limit for nitrate laid down in the EU- Drinking Water Directive is exceeded, sometimes considerably. In many cases this results from intensive agriculture in the catchment area in question. Under the terms of the EU’s Water Framework Directive the groundwater here is of poor quality and measures must be taken to improve it.
Quality of natural bathing water
Bathing water quality in Germany is monitored under Länder-level regulations that apply the values for excellent, good and sufficient bathing water quality as laid down in the EU Directive 2006/7/EC. This Directive replaces the 1975 Directive 76/160/ EEC. Since the 2008 bathing season, bathing waters are monitored under the new Directive. Classification requires data from four bathing seasons, and will only be available after the 2011 bathing season. Transitional rules apply until then.
In 2008 a total of 2 263 bathing waters in Germany were monitored under the new Directive, 373 of which were on the coast.
From 1992 to 2001 there was a steady reduction in non-compliance with the guide and imperative values. Since 2001 bathing water quality has been consistently high – on average 94 % of freshwater bathing places met the microbiological requirements, and 78 % the stricter guide values for good water quality. For coastal bathing waters the figures were 98 % and 87 % respectively.
With the new monitoring parameters in the 2008 bathing season an improvement in the quality of the freshwater bathing waters was observed. Considerably fewer of the coastal waters, however, were classified as good. This was partly because of a new classification for the estuary areas of the major coastal rivers such as the Elbe which usually do not have very good water quality. In line with the Water Framework Directive these have been classified as coastal waters instead of freshwater since the 2008 bathing season.
Only around 1 % of the 2 263 bathing waters had poor water quality in the 2008 bathing season.
The key drivers and pressures
The main sources of water pollution by nutrients and other pollutants are agriculture, municipal wastewater treatment plants, rainwater drainage from towns and cities, and industrial plants. However, water pollution caused by point-source discharges from wastewater treatment has fallen considerably. Currently development of treatment plants focussed on pollutants that cannot be degraded, including many pharmaceutical products and pesticides. Diffuse discharges of agricultural nutrients and pesticides and of heavy metals and organic substances from urban areas and transport are now the most important material pollutants of Germany’s inland waters. For the biotic communities of inland waters, structural loss is seen as an even bigger problem since it leads to the disappearance of entire habitats (see 2.2). For groundwater pollution, the removal of nitrogen resulting from the use of nitrate fertilisers and farmyard manure and leaching from pesticides is of paramount importance.
The nitrogen surplus determined from the total nitrogen balance is an indicator of potential discharges of nitrogen compounds into groundwater, surface waters and the air. It is calculated from the difference between nitrogen flows into agriculture and nitrogen flows exported from it. The figures given here are averages for Germany. In order to offset annual weather-dependent variations beyond anyone’s control, a sliding three-year average is taken for the middle year in each case.
Since 1993 the nitrogen surplus in the three-year average has fallen from 115 kg/ha and year to 105 kg/ha and year (see figure), corresponding to a reduction of 9 %. Overall, in the period from 1993 to 2007, just under a third of the target reduction by 2010 had been achieved. The reduction in the early 1990s was not because nitrogen was used more efficiently, rather because of the decline in the livestock population in the new Länder. In the past five years the average annual reduction in the balance has been less than 2 %, whereas it needed to decrease 10% a year between 2008 and 2010 for the target to be reached. The 2007 amendment to the Fertilisers Regulation introduced mandatory operational ceilings for the surplus of each farm. Further efforts to improve nitrogen use are needed.
Diffuse sources of nitrogen are always at a maximum where too many livestock are being kept on sites where there is a risk of leaching.
Nitrogen and phosphorus discharges into surface waters
In 2005 nitrogen discharges into surface waters stood at 565 kt/a, a reduction of 465 kt/a or 45% from the reference year of 1985 (see figure below). This meant that the internationally agreed target of halving nitrogen discharges into the oceans between 1985 and 2000 had still not been reached by 2005. Nitrogen discharges from point sources – municipal wastewater treatment plants and industrial dischargers – fell by 76 % between 1985 and 2005, reducing the proportion of the total discharge accounted for by point sources in 2005 to 18 %. This was largely due to more efficient wastewater treatment: in contrast, nitrogen discharges from diffuse sources fell by only 24%.
At 48 %, discharges through groundwater were overall the dominant entry route in 2005. Discharges into surface waters through erosion and atmospheric deposition accounted for only a small proportion of the total discharges – 2 % each.
Phosphorus discharges into surface waters nationwide stood at some 23 kt/a in 2005 (see figure below), a drop of around 58 kt/a – 71 % from the reference year of 1985. The target of halving phosphorus discharges into the oceans has thus been met in all river areas.
The reduction in phosphorus discharges is also largely due to the reduction in discharges from point sources – 86 %. However, despite this huge reduction, at 35 % of the total in 2005, discharges from point sources were still the most dominant entry route. Diffuse phosphorus discharges were reduced by only 29 %. The majority of this was accounted for by the 71 % reduction in discharges from urban areas, including combined sewer system overflows, rain discharges from separated sewer systems and wastewater from households not connected to a municipal treatment plant or sewer system.
Of the diffuse sources of phosphorus the main discharges are from erosion with 22 % of the total, followed by 20 % of discharges through groundwater.
Heavy metal discharges into surface waters
Heavy metal discharges into surface waters in Germany fell considerably between 1983 and 2005.
The targets set by the international marine conventions of reducing discharges of chromium, copper, nickel and zinc by 50 % and of cadmium, mercury and lead by 70 % from 1985 levels had been achieved or surpassed by 2005, with the sole exception of nickel, a very high percentage of which is geo-genic and unavoidable. The reductions in individual metals range from 47 % for nickel to 91 % for mercury, and are mainly the result of drastic reductions in point source industrial discharges, ranging from 89 % for lead to 99 % for mercury. Measures taken by industry to meet stricter statutory requirements have played a decisive part in these environmental improvements, as has the reduction in industrial activity in the new Länder since 1990.
In 2005 industrial discharges were responsible for only a very small proportion of the total discharge, ranging from 3% for nickel to 8 % for chromium.
Point source discharges from municipal wastewater treatment plants continued to be high, but in 2005 water pollution was dominated by discharges from diffuse sources that varied from 56 % for cadmium to 84 % for lead.
The main diffuse pathways were erosion, groundwater inflows and urban areas – particularly from sewer systems and residents not connected to mains sewers – that accounted for varying proportions of the heavy metals. Erosion discharges mainly involved chromium (62%) and lead (48%).
For nickel the main discharge – 45 %, – was geo-genic, through groundwater. A high percentage of the discharges, other than of nickel and chromium, into surface waters also comes from urban areas. This includes discharges from combined and separate sewer systems which account for particularly high proportions of the total discharge for zinc (39 %), copper (31 %) and lead (22 %). Since a significant proportion of the precipitation runoff in combined systems goes to wastewater treatment plants, such systems are preferable to separate systems as far as heavy metals are concerned (see figures 3 and 4).
Use of water resources
The main user groups – industry, including thermal power plants; public water supply; and agriculture – together took around 32 billion m³ from groundwater and surface water supplies in 2007.
Water extraction has been declining for years in all sectors, but the demand for water from thermal power stations has fallen the most.
At present the water demand from private households accounts for around 16 % of the total extracted; industry is responsible for the largest share of the demand with 84 %, over 73% of which is taken by thermal power plants, mainly for cooling, while just under 27% is needed by the mining and manufacturing industries for production processes. Water extraction for agriculture is not significant in Germany.
The total volume of 32.1 billion m³ represents less than 20 % of the potential water supply, in other words more than 80 % of the water supply is unused at present. The figure below shows the percentages of the main water users in proportion to the potential supply.
Existing and planned responses
The discharge of wastewater from municipalities and industry has fallen considerably in recent years, partly because chemical plants in the new Länder have stopped production, leading to a reduction in discharges into surface waters. In addition, changes to the Federal Water Act required municipal authorities and industry to take measures that led to an overall reduction in emissions from point sources. Improved wastewater purification techniques, the consistent application of state of the art technology and wastewater prevention led to an above-average reduction in pollutant emissions. Improvements in the industrial sector have been particularly evident since the early 1990s when wastewater management regulations came into force. Wastewater-free technologies, such as in pulp and paper production, flue gas purification, vehicle and reusable bottle cleaning, powder coating, and in screen-printing and materials synthesising have done much to reduce pollution. Procedures for recovering raw materials from wastewater and sewage sludge are helping to close materials’ life cycles. In future the main need will be to reduce pollution from agriculture and, where possible, to restore water bodies that have undergone structural change to their natural state.
In Germany the number of connections to wastewater treatment plants is very high:
In 2007, 96% of the entire resident population were connected to mains sewers and public wastewater treatment plants.
In 2007, a total of some 10.1 billion m³ of wastewater was treated in public plants and then discharged into surface waters. The total number of biological treatment plants has grown steadily, and as early as 2004 accounted for around 98 % of all treatment plants.
In 2007, a total of around 1 billion m³ of wastewater was treated in 2 813 in-house treatment plants in the mining and manufacturing industries. In 2004 67 % of this wastewater was purified biologically. Another 24 % went through a chemical or chemical-physical purification stage. Even in 2004 mechanical purification, with a 9 % share, was more or less insignificant. This shows the trend towards more efficient purification.
Alongside the reduction in point-source discharges into water-bodies, a number of measures have been taken in recent decades to reduce diffuse, widespread discharges. Huge efforts have been made to reduce the high nitrogen discharges from agriculture and diffuse pesticide discharges in particular. Even though these have already delivered significant reductions in water pollution, they are still not enough to achieve the aims of the Water Framework Directive – good water quality – everywhere in Germany. These measures therefore need to be continued and, in some cases, intensified.
The aim of the Water Framework Directive, which came into force in 2000, is to achieve good ecological and chemical water status by 2015. A further aim is to achieve concentrations of priority hazardous substances in the marine environment close to the background values for naturally occurring substances and close to zero for man-made synthetic substances – out-phasing. In addition to material targets, ecological water quality has also become a focus. Ecological targets are based on the populations of natural organisms in each particular water type and thus also on type-related morphological conditions. Monitoring programmes have been adapted to these new targets, so that biological water monitoring will become much more intensive. Representative data from these monitoring programmes will be available for the first time in 2010.