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24 Standards and Thresholds of the EU Water Framework Directive (WFD) – Phytoplankton and Lakes Brigitte Nixdorf1, Atis Rektins1 and Ute Mischke2 1 Chair of Freshwater Conservation, Research Station Bad Saarow, Brandenburg University of Technology (BTU), Germany 2 Leibniz-Institute of Freshwater Ecology and Inland Fisheries, Department of Shallow Lakes and Lowland Rivers, Berlin, Germany
24.1 Introduction Water protection policy of the European Union (EU) dates back to 1970s, especially to Paris Summit in 1972, where commitment was made to introduce common EU wide environmental policy that included protection of water resources (European Parliament 1972). Since then, several water quality acts have been passed, mostly regulating water pollution. As environmental issues took more important place in the political agenda and EU water policy was rather fragmented, consisting of many complex individual and fragmented regulations, the European Commission (EC) stressed out the need for an integrated approach to water resources covering both the quantitative and qualitative aspects of the policy, management of both surface water and groundwater, environmental protection and the links with other policies (EC 1994). The Water Framework Directive (WFD), proposed in 1994, was finally adopted in 2000. It applies to all water in the natural environment - rivers, lakes, estuaries and coastal waters as well as groundwater. Currently WFD has been implemented in national legislation of 25 EU countries and in four candidate countries – Romania and Bulgaria (expected to join the EU in 2007), Croatia and Macedonia, as well as in Iceland, Norway and Liechtenstein, principles of the WFD are partly taken into consideration in other EU neighbouring countries. Therefore, WFD has truly become the most comprehensive normative act regarding management of European waters. The WFD gradually (till 2013) repeals and replaces a number of older EC water directives - Exchange of Information Directive, Dangerous Substances Directive,
Standards and Thresholds for Impact Assessment. Edited by Michael Schmidt, John Glasson, Lars Emmelin and Hendrike Helbron. © 2008 Springer-Verlag
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Fish Water, Shellfish Water and Groundwater Directives and incorporates the remaining existing water Directives - the Bathing Water Directive, Nitrates Directive and Urban Waste Water Treatment Directives, into its framework through its protected areas provisions. Also all Natura 2000 sites in which quality of water is concerned (The Directives on the Protection of Habitats and Birds) must be incorporated into river basin management plans. It is expected that during the next few years Daughter Directives, which are currently being discussed, will amend the WFD – the Groundwater Directive (EC 2004), Floods Directive (EC 2006) and Priority Substances Directive (EC 2001).
24.2 WFD – Aim and Present State of the Implementation The aim of the WFD is to achieve the objective of at least good water status (when ecological functions of the water are not significantly altered) by defining and implementing the necessary measures; where good water status already exists, it should be maintained. Detailed definitions of good ecological status are provided in the WFD for different types of waters. They are given in terms of the quality of the biological community, the hydrological characteristics and the chemical characteristics. As there can not be fixed standards used throughout the EU for ecological quality, because of geographic variability, “good status” is defined as allowing a slight deviation from natural conditions due to anthropogenic impact. Additionally, EU-wide minimum requirements will be developed for 33 priority substances, when Priority Substances Directive will be adopted. Water management is based on River Basin Districts (RBD), which consist of river basins and associated lake, groundwater, transitional (estuaries) and coastal (up to 1 nautical mile from the coastline) water bodies. Total number of water bodies and their area differ from country to country, not only because of geographic conditions but also national water management policies, e.g. France and Sweden, countries of comparable land area, have respectively 3 900 and 12 300 surface water bodies. 24.2.1 Artificial and Heavily Modified Water Bodies Surface water bodies may also be designed as artificial or heavily modified, due to the fact that many watercourses, especially in heavily populated areas, have been modified from their natural conditions during the course of the last centuries and it might be impossible to restore them to natural conditions. Such deviations are applied to allow navigation, functioning of ports, recreation activities, activities for the purposes of which water is stored, such as drinking water supply, power generation or irrigation, as well as water regulation, flood protection, land drainage or other equally important sustainable human development activities. However, these exemptions are only possible when alternatives are technically unfeasible, they are disproportionately expensive or they produce worse environmental result. Artificial or heavily modified water bodies are required to achieve good ecologic poten-
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tial, instead of good ecological status – it reflects the values of ecological status for the closest comparable water body type, but with conditions from the artificial or heavily modified characteristics of the water body taken into consideration. 24.2.2 River Basin Management Plans and Monitoring For transboundary river basins, measures to achieve the environmental objectives set by the WFD, should be coordinated for the whole of the RBD, note separately for each country. Such approach is more natural and can also be more productive, there are already many successful examples in Europe, such as Danube or Rhine river basins. To report how environmental objectives of the WFD will be achieved, countries are required to produce River Basin Management Plans, each for every RBD lying entirely within their territory. The plan must contain the following elements: the river basin's characteristics, a summary of significant pressures and impact of human activity, information on the status of water quality in the basin and detailed information on environmental objectives established in the WFD regarding the particular river basin, including a set of measures how these objectives will be fulfilled. Also economic analysis of water use within the river basin must be carried out. In order to obtain information for preparation of River Basin Management Plans, data from water quality monitoring are necessary. The WFD defines three types of water quality monitoring: x operational monitoring – for water bodies which are at risk not to achieve “good status” and to assess changes resulting from the programmes of measures; x surveillance monitoring – to monitor long term trends and assessment of the overall surface water status; x investigative monitoring – to investigate reasons of unknown exceedances and in cases of accidental pollution.
24.3 Main Objectives of WFD and Intercalibration Main objectives of the WFD are defined in Article 4 and can be summarized as follows: For surface waters: x For all water bodies deterioration of the status should be prevented; x All water bodies should be protected, enhanced and restored with the aim of achieving good surface water status till 2015; x All artificial and heavily modified bodies of water, should be protected and enhanced with the aim of achieving good ecological potential and good surface water chemical status till 2015;
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x All the necessary measures should be taken, with the aim of progressively reducing pollution from priority substances and ceasing or phasing out emissions, discharges and losses of priority hazardous substances. For groundwater: x For all groundwater bodies the input of pollutants into groundwater and the deterioration of the status should be prevented or limited, x All groundwater bodies should be protected, enhanced and restored, to ensure a balance between abstraction and recharge of groundwater, with the aim of achieving good groundwater status till 2015. Additionally, the reference to “protected areas” is made, where compliance with any relevant environmental standards and objectives should be achieved till 2015. The WFD provides clear deadlines for carrying out the main activities, till 2006, RBDs had to be identified and elaborately characterized, also providing a review of the impact of human activity and an economic analysis of water use. Table 24.1. Timeline for WFD implementation Date 22 December 2006 22 December 2008 22 December 2009 2010 22 December 2012 22 December 2015 Every sixth year after 2015
Activity Monitoring networks are operational Drafts of River Basin Management Plans published First River Basin Management Plan published for each RBD, including programme of measures Water pricing policies are in place Programmes of measures for each RBD are operational, to achieve environmental objectives Main environmental objectives are achieved Review and update of River Basin Management Plans
Within this process every step of planning and design of River Basin Management Plans is connected with public participation playing an important role. It is done by providing that timetables, work programmes and draft River Basin Management Plans available for public to review and comment, up to three years before the period to which the plan refers. Intercalibration is essential for ensuring a comparable level of protection in consistency with the Directive. It is in order to ensure that class boundaries are established consistent with the normative definitions and are comparable between Member States. A number of additional research activities, provide support to the intercalibration exercise and improve the quality of the results. Intercalibration progress currently is slower than anticipated, as generally only one element for each water body (phytoplankton for lake, benthic invertebrates for river, macroalgae and angiosperms for coastal water bodies) is expected to sufficient intercalibration till the end of 2006 (ECOSTAT 2006). Therefore, it seems unlikely that the exercise will be completed within the deadline (August 2007) and its prolongation will be necessary. Main reason why intercalibration progress is relatively slow and not all the quality the elements are covered yet is that it is very difficult to find common metrics for comparatively large areas. There are signifi-
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cant gaps of knowledge, also for phytoplankton in lakes, from which the most notable are: x x x x x x
reference conditions in different lake types, threshold concentrations for high/good and good/moderate boundaries, taxonomic indicators for measuring impacts of nutrient pressures, establishment of supporting physicochemical conditions, effect of seasonal variability on classification schemes, ecological impact of nitrogen conditions (REBECCA 2005).
Usually different countries have different perceptions on issues which are not stated explicitly in the WFD, allowing certain flexibility – e.g. regarding design of monitoring networks, as only general principles are set. To deal with such situations, 14 non-binding guidelines (on intercalibration, monitoring, public participation, planning process etc) have been prepared and ongoing consultations and exchange of information between the actors involved are taking place.
24.4 Biological Quality Elements and Ecological Status Overview about Biological Quality Elements When assessing the ecological status of the water, biological quality elements are considered to be the most important, they are supported by hydromorphological and physico-chemical elements. Biological quality elements for the purposes of the WFD consist of: x Composition, abundance and biomass of phytoplankton; x Composition and abundance of other aquatic flora (macrophytes and microphytobenthos for lakes and rivers, macroalgae and angiosperms for coastal and transitional waters); x Composition and abundance of benthic invertebrate fauna; x Composition, abundance and age structure of fish fauna. Although such approach is not new, it has never been introduced in Europe in so large scale before. Many countries have changed their monitoring programmes significantly to adapt to the WFD requirements, as previously many of them had relied rather heavily on physico-chemical parameters, when assessing the water quality. Therefore new assessment methods have to be developed and implemented. Assessment based primarily on biological parameters is more complicated, as effects that specific changes in environment have on living organisms are not always fully understood. Following the WFD each country has to divide the water quality status for each surface water category into five classes - high, good, moderate, poor and bad. „High status” for biological, physicochemical and morphological quality elements is similar to totally or nearly totally, undisturbed conditions, also called „reference conditions” and are associated with no or very limited anthropogenic pressures.
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Further quality classes are based on the extent of deviation from the reference conditions. For surface waters, so-called „One out, all out” principle is used, meaning that the status of the water body is represented by the lowest of the values for the biological and physicochemical monitoring results for the relevant quality elements. To ensure that class boundaries are comparable between different countries, intercalibration exercise is carried out. Each participating country in 2003 and 2004 had to select sites representing ecological status at the boundaries between the “high” and “good” and between the “good” and “moderate” classifications, on the basis of provisional classification of their current national assessment methods. These sites were entered into EC intercalibration register, that currently includes 1489 sites from all 25 EU Member States, Bulgaria, Norway and Romania (EC 2005) Member States are divided into Geographical Intercalibration Groups (GIG), such as Rivers Central/Baltic (RCE), Lakes Alpine (LAL) or Mediterranean Atlantic GIG1, comprising Member States sharing particular surface water body types (EC 2005a). The main tasks for countries involved in is to find quantitative expressions (criteria or metrics) for the response in abundance and taxonomic composition for the different biological quality elements along the gradient of main pressures. For example, eutrophication can be reflected by quantifying the increased algal/plant biomass and the impact on other organisms and water quality (EC 2005b), in order to establish boundaries for good, moderate and poor ecological quality classes. 24.4.1 Phytoplankton - Ecological Quality Element and Indicator for Eutrophication Status of Freshwater Bodies Eutrophication is regarded as one of the most significant water protection issue in European waters; it is addressed in various international conventions, like Helsinki Convention, OSPAR Convention, Convention for the Protection of Rhine and others, as well as in other EU Directives – the Nitrates Directive and Urban Wastewater Treatment Directive (UWWT). In the UWWT Directive (EC 2005b) eutrophication is defined as the enrichment of water by nutrients, especially compounds of nitrogen and/or phosphorus, causing an accelerated growth of algae and higher forms of plant life to produce an undesirable disturbance to the balance of organisms present in the water and to the quality of the water concerned (EC 1991). However, the assessment of eutrophication status is integrated in the classification of surface water bodies - the definition of good ecological status for the quality elements “phytoplankton” and “macrophytes and phytobenthos” uses similar wording as the definition of eutrophication used in the UWWT and Nitrates Directives and by OSPAR (EC 2005b).
1
GIG acronyms: LAT – Lakes Atlantic; LCE – Lakes Central/Baltic; LME – Lakes Mediterranean; LNO – Lakes Northern; RAL – Rivers Alpine; REC – Rivers Eastern Continental; RME – Rivers Mediterranean; RNO – Rivers Northern.
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The phytoplankton community is considered to be the first biological community to respond to eutrophication pressures especially in lakes (REBECCA 1005). Phytoplankton is prescribed by the WFD as a quality element for lakes, but is not explicitly mentioned for rivers. Still, the appendix of the WFD provides a definition for high, good and moderate ecological status in rivers also for phytoplankton when it can be considered relevant for ecological status. Phytoplankton biomass is very low in low-order streams and increasing in high-order large rivers (Wetzel 2001). Germany (Mischke and Behrendt 2006) decided to restrict assessment on latter once. The WFD defines high, good and moderate status for three phytoplankton quality elements that potentially can be used to assess the ecological status of lakes: x Phytoplankton abundance and composition; x Phytoplankton biomass; x Planktonic bloom intensity and frequency. According to intercalibration milestone reports from September 2006, phytoplankton will be the only element intercalibrated by all lake GIGs till the end of 2006 (ECOSTAT 2006). Common metrics will be developed and agreed only for chlorophyll a concentrations, partly also phytoplankton biovolume, but there is work in progress by GIGs to intercalibrate also phytoplankton composition and proportion of cyanobacteria. Results can not be expected sooner than in 2007. River GIGs have not considered intercalibration of phytoplankton in their plans. For rivers the main uncertainties are relationships among nutrient concentrations and blooms, as nutrient concentration is not the only impact factor for triggering blooms (REBECCA 2005). Still, in slow flowing lowland rivers like river Elbe or Odra phytoplankton blooms can occur comparable to highly eutrophic lakes (Mischke and Behrendt 2006).
24.5 Phytoplankton Assessment System 24.5.1 Lake Types - Present State in Germany and Europe In Germany the trophic status of lakes is assessed by a seven level classification that was developed in 1999 by German Working Group of the Federal States on water issues (LAWA). It takes chlorophyll a concentrations, as well as Secchi depth and two parameters of total phosphorus into account (Nixdorf et al. 2006). However, there was an additional necessity to develop national ecological status assessment system for lakes, fully compliant with WFD requirements that would include composition, abundance and biomass of phytoplankton. Introduction of new parameters increased the sensitivity of evaluation. This work was completed in 2006 (Nixdorf et al. 2006) and is very lake type specific (Mischke et al. 2002).
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Table 24.2. Lake types in Germany and in European intercalibration lakes in the Alpine and Central lake GIG Characters for typing
Mixing type
VQ
Lake size
Residence time
Mean depth
Relevant in German type Relevant in IC lake type
yes Not in Central GIG
yes no
yes no
Yes in part differs
no yes
Mixing type: polymictic or stratified; VQ = area of catchment to lake volume = VQ large = >1.5 or VQ small <1.5; lake size (km2) = lake surface area = in DE always >0.5; residence time (yr) = calculated from mean precipitation, catchment area and lake volume without exchange with groundwater; in DE only relevant for riverine lakes (type 12); mean depth (m) = mean depth of the lake).
The German lake types are generally compliant with lake types used in the intercalibration exercise. Since the parameters defined for typing are different (see Table 24.2) the types are not completely compatible. The new assessment system was developed for 9 of the 14 lake types existing within Germany. Especially lakes and reservoirs of the eco-region Central Uplands cannot be assessed by now (see Table 24.3). Table 24.3. Comparison of German (DE type) and European intercalibration lake types (IC type) and thresholds for lake types in Germany (Mathes et al. 2002) and in Al pine (AL) and Central (LCB) lake GIG. Legends see Table 24.2 DE type number 1 2 3 4 5-9
11.2*
11.1
DE - Type name
Residence time [yr]
Calcareous, polymictic pre-alpine lake Calcareous, stratified pre-alpine lake with large catchment area Calcareous, stratified pre-alpine lake with small catchment area Calcareous, stratified alpine lake Calcareous and siliceous reservoirs and few lakes in the altitude range 200 – 800m Calcerous, polymictic very shallow lowland lake with large catchment area Calcareous, polymictic lowland lake with large catchment area
>0.084 IC = 0.1 – 1 > 0.084
Mean depth [m]
IC type name
Additional IC type character
IC = 3 - 15
AL4
IC = 3 - 15
AL4
IC > 15
AL3
Altitude 50 – 800m a.s.l.; Stratified Altitude 50 – 800m a.s.l.; stratified Altitude 200–800m a.s.l. Alpine catchment area
< and = 3m IC = < 3m >3m
LCB2
-
Calcareous Alk. >1 meq/l Altitude < 200m a.s.l. Most lakes excluded from LCB1 by residence time < 1
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Table 24.3. (cont.) DE type number 14 12
10
13
DE - Type name Calcareous, polymictic lowland lake with small catchment area River lakes - Calcareous, polymictic lowland lake with large catchment area and low retention time Calcareous, stratified lowland lakes with large catchment area Calcareous, stratified lowland lakes with small catchment area No siliceous lakes in German with surface area >0.5km2
*
Residence time [yr]
Mean depth [m]
0.008 – 0.084
IC type name -
Additional IC type character
-
Excluded from LCB1 and LCB2 by short residence time Calcareous Alk. >1 meq/l Altitude < 200m a.s.l. Calcareous Alk. >1 meq/l Altitude < 200m a.s.l. 0.2-1 meq/l Siliceous moderate alk. Altitude < 200m a.s.l.
IC = 1 – 10
IC = 315
LCB1
IC = 1 – 10
IC = 315
LCB1
IC = 315
LCB3
Excluded from LCB2 by residence time > 1
Very shallow lakes with a mean depth smaller than 3m are a sub-type of DE type 11 for phytoplankton, only.
To carry out assessment, three to four metrics have to be used: total phytoplankton biovolume, algae class and phytoplankton taxa in a special Lake Index (PTSI). In specific cases the forth value is required – evaluation of composition of yearly self sedimented planktonic diatoms. The data obtained, using lake-specific weighting constants are recalculated to obtain a common Phytoplankton Index in Lakes (PSI), reflecting the quality status in the water body. Assessment requires type specific reference conditions which were developed also by paleolimnological investigations (Nixdorf et al. 2006). 24.5.2 Class Boundaries for Common Phytoplankton Metrics Currently the German assessment method both in Central/Baltic (CB 1-3) and Alpine (AL3; AL4) GIGs is one of the most complete as most of the countries are still developing their metrics (EC, Joint Research Centre 2006 a, b). Further analysis are actually carried out to compare the results of national evaluation on a common European data set and to develop common metrics which are applicable in the whole eco-region. Preliminary results for thresholds of phytoplankton metrics Chl a- concentration and biovolume are given in Table 24.5 for Central Baltic lake types and 24.6 for IC lake types in the alpine eco-region (AL 3 and AL 4).
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Table 24.4. Overview of the German assessment method by means of phytoplankton Biological indicator All
Instructions for method The sampling frequency is at least 6 sampling per year with 4 sampling within the period between May to September. Untreated, integrated samples are usually taken from the epilimnion, in clear lakes from the euphotic zone and preserved with Lugol solution. Details are summarized in the German instruction for sampling. The basic unit of all parameters is the biovolume (mm3/l). It must be measured microscopically following the new CEN-norm for enumeration of phytoplankton by Utermöhl technique (EN 15204: 2006-12) in combination with the new national instructions, as to counting strategy, biovolume measuring and an operational German taxa list for phytoplankton. All biological parameters have a different indicative value in each lake type. Thus, the lake type of the investigated water body must be clear to select the type specific relevant parameters, thresholds and periods from the assessment tables, can not be shown here in detail.
Total biovolume assessment
Total biovolume is the sum of all phototrophic taxa enumerated including benthic once found in the plankton. Value of this parameter is the average of all sampling sites of one water body and of the whole vegetation period following a given instruction how to make averaging. Assessment is made by comparing the resulting value with lake type specific thresholds defined for all five ecological status classes. Actually a new national biomass metric is under development including also chlorophyll a mean and maxima values to fulfil ECOSTAT results.
Algal class assessment
For each lake type and each algal class it is defined weather the specific biovolume of an algal class or its proportion on total biovolume is to use. To optimize the indicative value, the method focuses on special periods of the yearly natural succession. Sample values are averaged for specific periods, e.g. proportion of dinophytes in summer (June-July) in case of the lake type 4 (alpine lakes). Defined for each lake type up to four different algal classes are indicators. Assessment is made by comparing values with thresholds defined for all or some of the five ecological status classes. Results of all algal class indices are averaged to one value to algal class metric. The level of required taxonomical detection is listed in the operational German taxa list. Each species biovolume (mm3/l) must be measured separately. The resulting species biovolume is attached to one of the 7 classes of abundance category defined for this method. Trophic values and weighting factors (“Stenökiefaktor”) of all indicator species are given in three different lists for alpine & pre-alpine lakes, for stratified lowland lakes and for polymictic lowland lakes. Both values are multiplied with the measured abundance category for each indicator species to calculate the PTSI index by an integral calculus. The indicative value of the indices “total biovolume”, “algal class metric” and “PTSI” is different in the lakes types, which is taken into account by incorporate weighting factors to calculate the final “ecological status”.
Indicator species assessment by PTSI
Phytoplankton index assessment
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Table 24.5. Reference values and H/G boundaries of chlorophyll-a concentration (µgL-1) in Central Baltic lakes types L-CB1
min
max L-CB2
min
Reference (median)*
3.2
2.6
3.8
6.8
6.7
7.4
3.1
2.5
3.7
H/G (75Th percentile)* EQR H/G
5.8
4.6
7.0
11
11
12
5.4
4.3
6.5
0.55
max
0.63
L-CB3
min
max
0.57
The EQR is calculated as reference value divided by the boundary value *only for mid value. Table 24.6. Class boundaries for the common metrics ”total biovolume” (BV) and “chlorophyll-a concentration” Chl-a) for the IC lake types L-AL3 and L-AL4 L-AL3 BV [mm3 L- Chl-a [µg L-1] 1 ] GIG MS GIG MS H/G (EQR = 0.8) 0.5 0.5 2.7 2.5 G/M (EQR = 0.6) 1.2 1.25 4.7 4.7 M/P (EQR = 0.4) 3.1 3.0 8.7 8.6 P/B (EQR = 0.2) 7.8 7.4 15.8 15.7 class width (In-scale) 0.9 0.9 0.6 0.6
L-AL4 BV [mm3 L-1] Chl-a [µg L-1] GIG 1.1 2.7 6.9 17.4 0.9
MS 1.1 2.25 4.6 9.5 0.7
GIG 4.4 8.0 14.6 26.7 0.6
MS 4.7 8.6 15.7 28.7 0.6
GIG = boundaries using the common GIG dataset and the BSP described under section B, C and Annex C, MS = Boundaries using a MS dataset in the German classification method.
24.6 European Standards (CEN) for Alpine and Lowland Regions for Lake Assessment and Sampling Procedure In order to ensure that in the process of assessment of ecological status sampling and analysis of parameters usually should be done according to international standards, accordingly verified and calibrated. The WFD (Annex V 1.3.6) requires for monitoring of quality elements standard methods to ensure scientific quality and comparability of these data throughout the EU (European Parliament 2000). Since the WFD was adopted, CEN (European Committee for Standardization CEN/TC (Technical Committee) 230/WG (Working Group) 2 is dealing with development of biological methods of water analysis has developed new standards, relevant for the WFD, which potentially can be considered for inclusion in the WFD (EC, Joint Research centre 2006). A Harmonisation Activity of the WFD has been assigned the role of compiling information on national biological monitoring methods, evaluating their comparability, identifying standards to be included in the WFD and well as fostering the link
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between CEN, European Commission and implementation working groups. In 2005 a document was drafted by DG Environment of the European Commission, to establish and agree the process of developing standard methods for the assessment of water status (EC, Joint Research Centre 2006). Currently there are 20 CEN Standards, which are suggested for inclusion in the WFD (EC, Joint Research Centre 2006), most of which are still under development or awaiting official approval, but it can be expected that most of them later will be included in Annex V of the WFD to supplement the existing information. These standards are mostly guidance standards, providing advice how to carry out certain activities, as it is not always possible to develop standards which would cover the wide variety of different climatic, geographic and other conditions in a large number of countries. To fully develop CEN standards there is a certain and comparatively lengthy procedure to be followed, to ensure that standards developed are fully functional. The most recent standards are those on analysing phytoplankton, since up to now in Europe there are very different techniques and counting strategies in use. Thus, it is great step forward, that the enumeration standard, titled: “Water quality - Guidance standard on the enumeration of phytoplankton using inverted microscopy (Utermöhl technique)” (Draft CEN standard prEN15204), is already in the formal vote procedure of CEN Still this new standard lacks the instruction, how to evaluate the parameter “biovolume”, which actually is suggested in a draft proposal by Germany for an additional guidance standard “”Phytoplankton biovolume determination using inverted microscopy (Utermöhl technique)” (German Draft Proposal for CEN guidance). Evaluation of biomass of phytoplankton instead of abundance allows more precise assessment and it can be considered more appropriate for food chain modelling than abundance. To calculate the biovolume of certain cells, for each phytoplankton taxa a fitting geometric shape is assigned and after measurements of cell dimensions have been carried out, the average cell volume is multiplied by the number of individuals (Draft CEN standard prEN15204).
24.7 Conclusions and Recommendations It can be expected that once the standardisation of methods is complete, the wide variety of standards will ensure that ecological status assessments produced by Member States are of the best quality and easily and reliably comparable in within European Union ever been before. On the other side, the ongoing process of European intercalibration within the GIG´s concerning defining of biological parameters and of common boundaries is not without risks: already finished national assessment methods come in conflict with common European boundaries, which could significantly differ from them. As it is stated by the ECOSTAT meeting in September 2006, the member states have to defend their national method, when deviations occur from a common GIG boundary.
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One reason for deviation is defining the intercalibration water body types much more roughly than it had happened on national member state level. This fact leads to comparable narrow thresholds for the bio-components of the water bodies, which could differ widely in respect to triggering habitat factors such as residual time of water or geogenic background. So, the evaluation by common metrics could mislead in the special case. In the GIG’s extreme strong criteria for selecting reference sites (EC REFCOND 2003) effect further deviations from the national methods. The latter consider regional aspects and included also water bodies, which were only stated to be “good” and not consequentially checked up for anthropogenic influences. Thus, the biological standards recently developed still have to be improved and must be harmonized. Furthermore they are under significant pressure of political interests.
References CEN – European Committee for Standardisation: standard EN 15204 “Water quality – Guidance standard on the enumeration of phytoplankton using inverted microscopy (Utermöhl technique)” ECOSTAT – Working Group 2.A – Ecological Status (2006) Milestone 6 reports, WFD CIRCA, Internet: http://forum.europa.eu.int/Public/irc/jrc/jrc_eewai/home EC – European Commission (1991) Council Directive of 21 May 1991 concerning urban waste treatment 91/271/EEC, OJ L135, 30.5.1991 EC (1994) Proposal for a Council Directive on the ecological quality of water - OJ C 222, 10.8.1994; COM(93) 680; Bull. 6-1994, point 1.2.179; Bull. 12-1994, point 1.2.206; http://europa.eu/bulletin/en/9601/p103149.htm EC (2001) Bulletin EU 11-2001, 1.4.42. Decision No 2455/2001/EC of the European Parliament and of the Council establishing the list of priority substances in the field of water policy and amending Directive 2000/60/EC EC (2004) Bulletin EU 1/2-2004, 1.4.56. Proposal for a European Parliament and Council directive on the protection of groundwater against pollution EC (2004) Common implementation strategy for the Water Framework Directive (2000/60/EC). Moving to next stage in the Common Implementation Strategy for the Water Framework Directive, Progress and work programme for 2005 and 2006 EC (2005a) Commission decision of 17 August 2005 on the establishment of a register of sites to form the intercalibration network in accordance with Directive 2000/60/EC of the European Parliament and of the Council 2005/646/EC, Official Journal of the European Union 19.9.2005, L243/1 EC (2005b) Towards a guidance document on eutrophication assessment in the context of European water policies EC (2006) Bulletin EU 1/2-2006, 1.20.19. Proposal for a directive of the European Parliament and of the Council on the assessment and management of floods EC, Joint Research Centre (2005) Report on harmonisation of freshwater biology methods. Internet: http://ies.jrc.cec.eu.int/fileadmin/Documentation/Reports/Inland_and_Marine _Waters/EUR_2005/Harmonisation__EUR_21769_EN.pdf
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EC, Joint Research Centre (2006a) Intercalibration Lakes GIG report Central/Baltic, Internet: http://forum.europa.eu.int/Public/irc/jrc/jrc_eewai/home EC, Joint Research Centre (2006b) Intercalibration Lakes GIG report Alpine, Internet: http://forum.europa.eu.int/Public/irc/jrc/jrc_eewai/home EC, Joint Research Centre (2006c) Proposal for revision of the CEN methods in Annex V of the WFD and identification of future standardisation items EC, REFCOND (2003) Common implementation strategy for the water framework directive (2000/60/EC) - Guidance Document No 10- Rivers and Lakes – Typology, Reference Conditions and Classification Systems - Produced by Working Group 2.3 – REFCOND. Internet, Europa server: http://europa.eu.int European Committee for Standardization, CEN TC/230 structure, Internet on: http://www. cenorm.be/CENORM/BusinessDomains/TechnicalCommitteesWorkshops/CENTechni calCommittees/TCStruc.asp?param=6211&title=CEN%2FTC+230, last accessed on 24.03.2007 European Parliament (1972) Resolution of the European Parliament on the Results The First Summit Conference of the Enlarged Community, Paris 19-21 October, Bulletin of the European Communities, No 11, 1972 European Parliament (2000) Directive 2000/60/EC of the European Parliament and of the Council of establishing a framework for Community action in the field of water policy, Official Journal of the European Union (OJ L 327) German Draft proposal for CEN guidance standard ”Phytoplankton biovolume determination using inverted microscopy (Utermöhl technique)” Mischke U, Behrendt H (2006) Handbook to describe the assessment method to evaluate rivers by phytoplankton [in German]. In press. In: Bundesweiter Praxistest eines Bewertungsverfahren für Phytoplankton in Fließgewässern Deutschlands zur Umsetzung der EU-Wasserrahmenrichtlinie. Report IGB, Berlin, p. 68 Mischke U, Nixdorf B, Behrendt H (2002) On typology and reference conditions for phytoplankton in rivers and lakes in Germany. In: Ruoppa M, Heinonen P, Pilke A, Rekolainen S, Toivonen H, Vuoristo H (eds) Nordic Council of Ministers, Copenhagen. TemaNord 566:44-49. Internet: http://www.norden.org/pub/webordering/sk/, last accessed on 24.03.2007 Nixdorf B, Mischke U, Hoehn E, Riedmüller U (2006) Leitbildorientierte Bewertung von Seen anhand der Teilkomponente Phytoplankton im Rahmen der Umsetzung der EUWasserrahmenrichtlinie, Bad Saarow, Internet: http://www.tu-cottbus.de/BTU/Fak4/ Gewschu/, last accessed on 24.03.2007 REBECCA (2005) Relationships between pressures, chemical status, and biological quality elements. Analysis of the current knowledge gaps for the implementation of the Water Framework Directive Response to the proposal of Dr. Georg Wolfram 13.01.2006 for the Alpine GIG-boundary setting draft for phytoplankton in lakes in the Alpine region Water Framework Directive, Directive 2000/60/EC of the European Parliament and of the Council of 23 October 2000 establishing a framework for Community action in the field of water policy, OJ L 327 of 22.12.2000, p. 1, corr. OJ L 017 of 19.01.2001, p. 39 Wetzel RG (2001) Limnology. Elsevier, Amsterdam, p. 390
24.1 Introduction Water protection policy of the European Union (EU) dates back to 1970s, especially to Paris Summit in 1972, where commitment was made to introduce common EU wide environmental policy that included protection of water resources (European Parliament 1972). Since then, several water quality acts have been passed, mostly regulating water pollution. As environmental issues took more important place in the political agenda and EU water policy was rather fragmented, consisting of many complex individual and fragmented regulations, the European Commission (EC) stressed out the need for an integrated approach to water resources covering both the quantitative and qualitative aspects of the policy, management of both surface water and groundwater, environmental protection and the links with other policies (EC 1994). The Water Framework Directive (WFD), proposed in 1994, was finally adopted in 2000. It applies to all water in the natural environment - rivers, lakes, estuaries and coastal waters as well as groundwater. Currently WFD has been implemented in national legislation of 25 EU countries and in four candidate countries – Romania and Bulgaria (expected to join the EU in 2007), Croatia and Macedonia, as well as in Iceland, Norway and Liechtenstein, principles of the WFD are partly taken into consideration in other EU neighbouring countries. Therefore, WFD has truly become the most comprehensive normative act regarding management of European waters. The WFD gradually (till 2013) repeals and replaces a number of older EC water directives - Exchange of Information Directive, Dangerous Substances Directive,
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Fish Water, Shellfish Water and Groundwater Directives and incorporates the remaining existing water Directives - the Bathing Water Directive, Nitrates Directive and Urban Waste Water Treatment Directives, into its framework through its protected areas provisions. Also all Natura 2000 sites in which quality of water is concerned (The Directives on the Protection of Habitats and Birds) must be incorporated into river basin management plans. It is expected that during the next few years Daughter Directives, which are currently being discussed, will amend the WFD – the Groundwater Directive (EC 2004), Floods Directive (EC 2006) and Priority Substances Directive (EC 2001).
24.2 WFD – Aim and Present State of the Implementation The aim of the WFD is to achieve the objective of at least good water status (when ecological functions of the water are not significantly altered) by defining and implementing the necessary measures; where good water status already exists, it should be maintained. Detailed definitions of good ecological status are provided in the WFD for different types of waters. They are given in terms of the quality of the biological community, the hydrological characteristics and the chemical characteristics. As there can not be fixed standards used throughout the EU for ecological quality, because of geographic variability, “good status” is defined as allowing a slight deviation from natural conditions due to anthropogenic impact. Additionally, EU-wide minimum requirements will be developed for 33 priority substances, when Priority Substances Directive will be adopted. Water management is based on River Basin Districts (RBD), which consist of river basins and associated lake, groundwater, transitional (estuaries) and coastal (up to 1 nautical mile from the coastline) water bodies. Total number of water bodies and their area differ from country to country, not only because of geographic conditions but also national water management policies, e.g. France and Sweden, countries of comparable land area, have respectively 3 900 and 12 300 surface water bodies. 24.2.1 Artificial and Heavily Modified Water Bodies Surface water bodies may also be designed as artificial or heavily modified, due to the fact that many watercourses, especially in heavily populated areas, have been modified from their natural conditions during the course of the last centuries and it might be impossible to restore them to natural conditions. Such deviations are applied to allow navigation, functioning of ports, recreation activities, activities for the purposes of which water is stored, such as drinking water supply, power generation or irrigation, as well as water regulation, flood protection, land drainage or other equally important sustainable human development activities. However, these exemptions are only possible when alternatives are technically unfeasible, they are disproportionately expensive or they produce worse environmental result. Artificial or heavily modified water bodies are required to achieve good ecologic poten-
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tial, instead of good ecological status – it reflects the values of ecological status for the closest comparable water body type, but with conditions from the artificial or heavily modified characteristics of the water body taken into consideration. 24.2.2 River Basin Management Plans and Monitoring For transboundary river basins, measures to achieve the environmental objectives set by the WFD, should be coordinated for the whole of the RBD, note separately for each country. Such approach is more natural and can also be more productive, there are already many successful examples in Europe, such as Danube or Rhine river basins. To report how environmental objectives of the WFD will be achieved, countries are required to produce River Basin Management Plans, each for every RBD lying entirely within their territory. The plan must contain the following elements: the river basin's characteristics, a summary of significant pressures and impact of human activity, information on the status of water quality in the basin and detailed information on environmental objectives established in the WFD regarding the particular river basin, including a set of measures how these objectives will be fulfilled. Also economic analysis of water use within the river basin must be carried out. In order to obtain information for preparation of River Basin Management Plans, data from water quality monitoring are necessary. The WFD defines three types of water quality monitoring: x operational monitoring – for water bodies which are at risk not to achieve “good status” and to assess changes resulting from the programmes of measures; x surveillance monitoring – to monitor long term trends and assessment of the overall surface water status; x investigative monitoring – to investigate reasons of unknown exceedances and in cases of accidental pollution.
24.3 Main Objectives of WFD and Intercalibration Main objectives of the WFD are defined in Article 4 and can be summarized as follows: For surface waters: x For all water bodies deterioration of the status should be prevented; x All water bodies should be protected, enhanced and restored with the aim of achieving good surface water status till 2015; x All artificial and heavily modified bodies of water, should be protected and enhanced with the aim of achieving good ecological potential and good surface water chemical status till 2015;
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x All the necessary measures should be taken, with the aim of progressively reducing pollution from priority substances and ceasing or phasing out emissions, discharges and losses of priority hazardous substances. For groundwater: x For all groundwater bodies the input of pollutants into groundwater and the deterioration of the status should be prevented or limited, x All groundwater bodies should be protected, enhanced and restored, to ensure a balance between abstraction and recharge of groundwater, with the aim of achieving good groundwater status till 2015. Additionally, the reference to “protected areas” is made, where compliance with any relevant environmental standards and objectives should be achieved till 2015. The WFD provides clear deadlines for carrying out the main activities, till 2006, RBDs had to be identified and elaborately characterized, also providing a review of the impact of human activity and an economic analysis of water use. Table 24.1. Timeline for WFD implementation Date 22 December 2006 22 December 2008 22 December 2009 2010 22 December 2012 22 December 2015 Every sixth year after 2015
Activity Monitoring networks are operational Drafts of River Basin Management Plans published First River Basin Management Plan published for each RBD, including programme of measures Water pricing policies are in place Programmes of measures for each RBD are operational, to achieve environmental objectives Main environmental objectives are achieved Review and update of River Basin Management Plans
Within this process every step of planning and design of River Basin Management Plans is connected with public participation playing an important role. It is done by providing that timetables, work programmes and draft River Basin Management Plans available for public to review and comment, up to three years before the period to which the plan refers. Intercalibration is essential for ensuring a comparable level of protection in consistency with the Directive. It is in order to ensure that class boundaries are established consistent with the normative definitions and are comparable between Member States. A number of additional research activities, provide support to the intercalibration exercise and improve the quality of the results. Intercalibration progress currently is slower than anticipated, as generally only one element for each water body (phytoplankton for lake, benthic invertebrates for river, macroalgae and angiosperms for coastal water bodies) is expected to sufficient intercalibration till the end of 2006 (ECOSTAT 2006). Therefore, it seems unlikely that the exercise will be completed within the deadline (August 2007) and its prolongation will be necessary. Main reason why intercalibration progress is relatively slow and not all the quality the elements are covered yet is that it is very difficult to find common metrics for comparatively large areas. There are signifi-
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cant gaps of knowledge, also for phytoplankton in lakes, from which the most notable are: x x x x x x
reference conditions in different lake types, threshold concentrations for high/good and good/moderate boundaries, taxonomic indicators for measuring impacts of nutrient pressures, establishment of supporting physicochemical conditions, effect of seasonal variability on classification schemes, ecological impact of nitrogen conditions (REBECCA 2005).
Usually different countries have different perceptions on issues which are not stated explicitly in the WFD, allowing certain flexibility – e.g. regarding design of monitoring networks, as only general principles are set. To deal with such situations, 14 non-binding guidelines (on intercalibration, monitoring, public participation, planning process etc) have been prepared and ongoing consultations and exchange of information between the actors involved are taking place.
24.4 Biological Quality Elements and Ecological Status Overview about Biological Quality Elements When assessing the ecological status of the water, biological quality elements are considered to be the most important, they are supported by hydromorphological and physico-chemical elements. Biological quality elements for the purposes of the WFD consist of: x Composition, abundance and biomass of phytoplankton; x Composition and abundance of other aquatic flora (macrophytes and microphytobenthos for lakes and rivers, macroalgae and angiosperms for coastal and transitional waters); x Composition and abundance of benthic invertebrate fauna; x Composition, abundance and age structure of fish fauna. Although such approach is not new, it has never been introduced in Europe in so large scale before. Many countries have changed their monitoring programmes significantly to adapt to the WFD requirements, as previously many of them had relied rather heavily on physico-chemical parameters, when assessing the water quality. Therefore new assessment methods have to be developed and implemented. Assessment based primarily on biological parameters is more complicated, as effects that specific changes in environment have on living organisms are not always fully understood. Following the WFD each country has to divide the water quality status for each surface water category into five classes - high, good, moderate, poor and bad. „High status” for biological, physicochemical and morphological quality elements is similar to totally or nearly totally, undisturbed conditions, also called „reference conditions” and are associated with no or very limited anthropogenic pressures.
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Further quality classes are based on the extent of deviation from the reference conditions. For surface waters, so-called „One out, all out” principle is used, meaning that the status of the water body is represented by the lowest of the values for the biological and physicochemical monitoring results for the relevant quality elements. To ensure that class boundaries are comparable between different countries, intercalibration exercise is carried out. Each participating country in 2003 and 2004 had to select sites representing ecological status at the boundaries between the “high” and “good” and between the “good” and “moderate” classifications, on the basis of provisional classification of their current national assessment methods. These sites were entered into EC intercalibration register, that currently includes 1489 sites from all 25 EU Member States, Bulgaria, Norway and Romania (EC 2005) Member States are divided into Geographical Intercalibration Groups (GIG), such as Rivers Central/Baltic (RCE), Lakes Alpine (LAL) or Mediterranean Atlantic GIG1, comprising Member States sharing particular surface water body types (EC 2005a). The main tasks for countries involved in is to find quantitative expressions (criteria or metrics) for the response in abundance and taxonomic composition for the different biological quality elements along the gradient of main pressures. For example, eutrophication can be reflected by quantifying the increased algal/plant biomass and the impact on other organisms and water quality (EC 2005b), in order to establish boundaries for good, moderate and poor ecological quality classes. 24.4.1 Phytoplankton - Ecological Quality Element and Indicator for Eutrophication Status of Freshwater Bodies Eutrophication is regarded as one of the most significant water protection issue in European waters; it is addressed in various international conventions, like Helsinki Convention, OSPAR Convention, Convention for the Protection of Rhine and others, as well as in other EU Directives – the Nitrates Directive and Urban Wastewater Treatment Directive (UWWT). In the UWWT Directive (EC 2005b) eutrophication is defined as the enrichment of water by nutrients, especially compounds of nitrogen and/or phosphorus, causing an accelerated growth of algae and higher forms of plant life to produce an undesirable disturbance to the balance of organisms present in the water and to the quality of the water concerned (EC 1991). However, the assessment of eutrophication status is integrated in the classification of surface water bodies - the definition of good ecological status for the quality elements “phytoplankton” and “macrophytes and phytobenthos” uses similar wording as the definition of eutrophication used in the UWWT and Nitrates Directives and by OSPAR (EC 2005b).
1
GIG acronyms: LAT – Lakes Atlantic; LCE – Lakes Central/Baltic; LME – Lakes Mediterranean; LNO – Lakes Northern; RAL – Rivers Alpine; REC – Rivers Eastern Continental; RME – Rivers Mediterranean; RNO – Rivers Northern.
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The phytoplankton community is considered to be the first biological community to respond to eutrophication pressures especially in lakes (REBECCA 1005). Phytoplankton is prescribed by the WFD as a quality element for lakes, but is not explicitly mentioned for rivers. Still, the appendix of the WFD provides a definition for high, good and moderate ecological status in rivers also for phytoplankton when it can be considered relevant for ecological status. Phytoplankton biomass is very low in low-order streams and increasing in high-order large rivers (Wetzel 2001). Germany (Mischke and Behrendt 2006) decided to restrict assessment on latter once. The WFD defines high, good and moderate status for three phytoplankton quality elements that potentially can be used to assess the ecological status of lakes: x Phytoplankton abundance and composition; x Phytoplankton biomass; x Planktonic bloom intensity and frequency. According to intercalibration milestone reports from September 2006, phytoplankton will be the only element intercalibrated by all lake GIGs till the end of 2006 (ECOSTAT 2006). Common metrics will be developed and agreed only for chlorophyll a concentrations, partly also phytoplankton biovolume, but there is work in progress by GIGs to intercalibrate also phytoplankton composition and proportion of cyanobacteria. Results can not be expected sooner than in 2007. River GIGs have not considered intercalibration of phytoplankton in their plans. For rivers the main uncertainties are relationships among nutrient concentrations and blooms, as nutrient concentration is not the only impact factor for triggering blooms (REBECCA 2005). Still, in slow flowing lowland rivers like river Elbe or Odra phytoplankton blooms can occur comparable to highly eutrophic lakes (Mischke and Behrendt 2006).
24.5 Phytoplankton Assessment System 24.5.1 Lake Types - Present State in Germany and Europe In Germany the trophic status of lakes is assessed by a seven level classification that was developed in 1999 by German Working Group of the Federal States on water issues (LAWA). It takes chlorophyll a concentrations, as well as Secchi depth and two parameters of total phosphorus into account (Nixdorf et al. 2006). However, there was an additional necessity to develop national ecological status assessment system for lakes, fully compliant with WFD requirements that would include composition, abundance and biomass of phytoplankton. Introduction of new parameters increased the sensitivity of evaluation. This work was completed in 2006 (Nixdorf et al. 2006) and is very lake type specific (Mischke et al. 2002).
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Table 24.2. Lake types in Germany and in European intercalibration lakes in the Alpine and Central lake GIG Characters for typing
Mixing type
VQ
Lake size
Residence time
Mean depth
Relevant in German type Relevant in IC lake type
yes Not in Central GIG
yes no
yes no
Yes in part differs
no yes
Mixing type: polymictic or stratified; VQ = area of catchment to lake volume = VQ large = >1.5 or VQ small <1.5; lake size (km2) = lake surface area = in DE always >0.5; residence time (yr) = calculated from mean precipitation, catchment area and lake volume without exchange with groundwater; in DE only relevant for riverine lakes (type 12); mean depth (m) = mean depth of the lake).
The German lake types are generally compliant with lake types used in the intercalibration exercise. Since the parameters defined for typing are different (see Table 24.2) the types are not completely compatible. The new assessment system was developed for 9 of the 14 lake types existing within Germany. Especially lakes and reservoirs of the eco-region Central Uplands cannot be assessed by now (see Table 24.3). Table 24.3. Comparison of German (DE type) and European intercalibration lake types (IC type) and thresholds for lake types in Germany (Mathes et al. 2002) and in Al pine (AL) and Central (LCB) lake GIG. Legends see Table 24.2 DE type number 1 2 3 4 5-9
11.2*
11.1
DE - Type name
Residence time [yr]
Calcareous, polymictic pre-alpine lake Calcareous, stratified pre-alpine lake with large catchment area Calcareous, stratified pre-alpine lake with small catchment area Calcareous, stratified alpine lake Calcareous and siliceous reservoirs and few lakes in the altitude range 200 – 800m Calcerous, polymictic very shallow lowland lake with large catchment area Calcareous, polymictic lowland lake with large catchment area
>0.084 IC = 0.1 – 1 > 0.084
Mean depth [m]
IC type name
Additional IC type character
IC = 3 - 15
AL4
IC = 3 - 15
AL4
IC > 15
AL3
Altitude 50 – 800m a.s.l.; Stratified Altitude 50 – 800m a.s.l.; stratified Altitude 200–800m a.s.l. Alpine catchment area
< and = 3m IC = < 3m >3m
LCB2
-
Calcareous Alk. >1 meq/l Altitude < 200m a.s.l. Most lakes excluded from LCB1 by residence time < 1
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Table 24.3. (cont.) DE type number 14 12
10
13
DE - Type name Calcareous, polymictic lowland lake with small catchment area River lakes - Calcareous, polymictic lowland lake with large catchment area and low retention time Calcareous, stratified lowland lakes with large catchment area Calcareous, stratified lowland lakes with small catchment area No siliceous lakes in German with surface area >0.5km2
*
Residence time [yr]
Mean depth [m]
0.008 – 0.084
IC type name -
Additional IC type character
-
Excluded from LCB1 and LCB2 by short residence time Calcareous Alk. >1 meq/l Altitude < 200m a.s.l. Calcareous Alk. >1 meq/l Altitude < 200m a.s.l. 0.2-1 meq/l Siliceous moderate alk. Altitude < 200m a.s.l.
IC = 1 – 10
IC = 315
LCB1
IC = 1 – 10
IC = 315
LCB1
IC = 315
LCB3
Excluded from LCB2 by residence time > 1
Very shallow lakes with a mean depth smaller than 3m are a sub-type of DE type 11 for phytoplankton, only.
To carry out assessment, three to four metrics have to be used: total phytoplankton biovolume, algae class and phytoplankton taxa in a special Lake Index (PTSI). In specific cases the forth value is required – evaluation of composition of yearly self sedimented planktonic diatoms. The data obtained, using lake-specific weighting constants are recalculated to obtain a common Phytoplankton Index in Lakes (PSI), reflecting the quality status in the water body. Assessment requires type specific reference conditions which were developed also by paleolimnological investigations (Nixdorf et al. 2006). 24.5.2 Class Boundaries for Common Phytoplankton Metrics Currently the German assessment method both in Central/Baltic (CB 1-3) and Alpine (AL3; AL4) GIGs is one of the most complete as most of the countries are still developing their metrics (EC, Joint Research Centre 2006 a, b). Further analysis are actually carried out to compare the results of national evaluation on a common European data set and to develop common metrics which are applicable in the whole eco-region. Preliminary results for thresholds of phytoplankton metrics Chl a- concentration and biovolume are given in Table 24.5 for Central Baltic lake types and 24.6 for IC lake types in the alpine eco-region (AL 3 and AL 4).
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Table 24.4. Overview of the German assessment method by means of phytoplankton Biological indicator All
Instructions for method The sampling frequency is at least 6 sampling per year with 4 sampling within the period between May to September. Untreated, integrated samples are usually taken from the epilimnion, in clear lakes from the euphotic zone and preserved with Lugol solution. Details are summarized in the German instruction for sampling. The basic unit of all parameters is the biovolume (mm3/l). It must be measured microscopically following the new CEN-norm for enumeration of phytoplankton by Utermöhl technique (EN 15204: 2006-12) in combination with the new national instructions, as to counting strategy, biovolume measuring and an operational German taxa list for phytoplankton. All biological parameters have a different indicative value in each lake type. Thus, the lake type of the investigated water body must be clear to select the type specific relevant parameters, thresholds and periods from the assessment tables, can not be shown here in detail.
Total biovolume assessment
Total biovolume is the sum of all phototrophic taxa enumerated including benthic once found in the plankton. Value of this parameter is the average of all sampling sites of one water body and of the whole vegetation period following a given instruction how to make averaging. Assessment is made by comparing the resulting value with lake type specific thresholds defined for all five ecological status classes. Actually a new national biomass metric is under development including also chlorophyll a mean and maxima values to fulfil ECOSTAT results.
Algal class assessment
For each lake type and each algal class it is defined weather the specific biovolume of an algal class or its proportion on total biovolume is to use. To optimize the indicative value, the method focuses on special periods of the yearly natural succession. Sample values are averaged for specific periods, e.g. proportion of dinophytes in summer (June-July) in case of the lake type 4 (alpine lakes). Defined for each lake type up to four different algal classes are indicators. Assessment is made by comparing values with thresholds defined for all or some of the five ecological status classes. Results of all algal class indices are averaged to one value to algal class metric. The level of required taxonomical detection is listed in the operational German taxa list. Each species biovolume (mm3/l) must be measured separately. The resulting species biovolume is attached to one of the 7 classes of abundance category defined for this method. Trophic values and weighting factors (“Stenökiefaktor”) of all indicator species are given in three different lists for alpine & pre-alpine lakes, for stratified lowland lakes and for polymictic lowland lakes. Both values are multiplied with the measured abundance category for each indicator species to calculate the PTSI index by an integral calculus. The indicative value of the indices “total biovolume”, “algal class metric” and “PTSI” is different in the lakes types, which is taken into account by incorporate weighting factors to calculate the final “ecological status”.
Indicator species assessment by PTSI
Phytoplankton index assessment
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Table 24.5. Reference values and H/G boundaries of chlorophyll-a concentration (µgL-1) in Central Baltic lakes types L-CB1
min
max L-CB2
min
Reference (median)*
3.2
2.6
3.8
6.8
6.7
7.4
3.1
2.5
3.7
H/G (75Th percentile)* EQR H/G
5.8
4.6
7.0
11
11
12
5.4
4.3
6.5
0.55
max
0.63
L-CB3
min
max
0.57
The EQR is calculated as reference value divided by the boundary value *only for mid value. Table 24.6. Class boundaries for the common metrics ”total biovolume” (BV) and “chlorophyll-a concentration” Chl-a) for the IC lake types L-AL3 and L-AL4 L-AL3 BV [mm3 L- Chl-a [µg L-1] 1 ] GIG MS GIG MS H/G (EQR = 0.8) 0.5 0.5 2.7 2.5 G/M (EQR = 0.6) 1.2 1.25 4.7 4.7 M/P (EQR = 0.4) 3.1 3.0 8.7 8.6 P/B (EQR = 0.2) 7.8 7.4 15.8 15.7 class width (In-scale) 0.9 0.9 0.6 0.6
L-AL4 BV [mm3 L-1] Chl-a [µg L-1] GIG 1.1 2.7 6.9 17.4 0.9
MS 1.1 2.25 4.6 9.5 0.7
GIG 4.4 8.0 14.6 26.7 0.6
MS 4.7 8.6 15.7 28.7 0.6
GIG = boundaries using the common GIG dataset and the BSP described under section B, C and Annex C, MS = Boundaries using a MS dataset in the German classification method.
24.6 European Standards (CEN) for Alpine and Lowland Regions for Lake Assessment and Sampling Procedure In order to ensure that in the process of assessment of ecological status sampling and analysis of parameters usually should be done according to international standards, accordingly verified and calibrated. The WFD (Annex V 1.3.6) requires for monitoring of quality elements standard methods to ensure scientific quality and comparability of these data throughout the EU (European Parliament 2000). Since the WFD was adopted, CEN (European Committee for Standardization CEN/TC (Technical Committee) 230/WG (Working Group) 2 is dealing with development of biological methods of water analysis has developed new standards, relevant for the WFD, which potentially can be considered for inclusion in the WFD (EC, Joint Research centre 2006). A Harmonisation Activity of the WFD has been assigned the role of compiling information on national biological monitoring methods, evaluating their comparability, identifying standards to be included in the WFD and well as fostering the link
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between CEN, European Commission and implementation working groups. In 2005 a document was drafted by DG Environment of the European Commission, to establish and agree the process of developing standard methods for the assessment of water status (EC, Joint Research Centre 2006). Currently there are 20 CEN Standards, which are suggested for inclusion in the WFD (EC, Joint Research Centre 2006), most of which are still under development or awaiting official approval, but it can be expected that most of them later will be included in Annex V of the WFD to supplement the existing information. These standards are mostly guidance standards, providing advice how to carry out certain activities, as it is not always possible to develop standards which would cover the wide variety of different climatic, geographic and other conditions in a large number of countries. To fully develop CEN standards there is a certain and comparatively lengthy procedure to be followed, to ensure that standards developed are fully functional. The most recent standards are those on analysing phytoplankton, since up to now in Europe there are very different techniques and counting strategies in use. Thus, it is great step forward, that the enumeration standard, titled: “Water quality - Guidance standard on the enumeration of phytoplankton using inverted microscopy (Utermöhl technique)” (Draft CEN standard prEN15204), is already in the formal vote procedure of CEN Still this new standard lacks the instruction, how to evaluate the parameter “biovolume”, which actually is suggested in a draft proposal by Germany for an additional guidance standard “”Phytoplankton biovolume determination using inverted microscopy (Utermöhl technique)” (German Draft Proposal for CEN guidance). Evaluation of biomass of phytoplankton instead of abundance allows more precise assessment and it can be considered more appropriate for food chain modelling than abundance. To calculate the biovolume of certain cells, for each phytoplankton taxa a fitting geometric shape is assigned and after measurements of cell dimensions have been carried out, the average cell volume is multiplied by the number of individuals (Draft CEN standard prEN15204).
24.7 Conclusions and Recommendations It can be expected that once the standardisation of methods is complete, the wide variety of standards will ensure that ecological status assessments produced by Member States are of the best quality and easily and reliably comparable in within European Union ever been before. On the other side, the ongoing process of European intercalibration within the GIG´s concerning defining of biological parameters and of common boundaries is not without risks: already finished national assessment methods come in conflict with common European boundaries, which could significantly differ from them. As it is stated by the ECOSTAT meeting in September 2006, the member states have to defend their national method, when deviations occur from a common GIG boundary.
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One reason for deviation is defining the intercalibration water body types much more roughly than it had happened on national member state level. This fact leads to comparable narrow thresholds for the bio-components of the water bodies, which could differ widely in respect to triggering habitat factors such as residual time of water or geogenic background. So, the evaluation by common metrics could mislead in the special case. In the GIG’s extreme strong criteria for selecting reference sites (EC REFCOND 2003) effect further deviations from the national methods. The latter consider regional aspects and included also water bodies, which were only stated to be “good” and not consequentially checked up for anthropogenic influences. Thus, the biological standards recently developed still have to be improved and must be harmonized. Furthermore they are under significant pressure of political interests.
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