National Report on the Eutrophication Status of UK waters 

April 2008 

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Common Procedure for the Identification of the 

Eutrophication Status of the OSPAR Maritime Area 

UK National Report 
National Report on the Eutrophication Status of UK waters 

April 2008 

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Table of contents 

Table of contents ___________________________________________________________ 2

1 Introduction __________________________________________________________ 4

2 Description of assessed areas _____________________________________________ 6

3 Methods and data ______________________________________________________ 9

3.1 Criteria for the OSPAR Comprehensive Procedure assessment ___________ 9

3.2 Inventory of available data_________________________________________ 15

4 Eutrophication assessment ______________________________________________ 18

4.1 Outline of assessment process ______________________________________ 18

4.2 Assessment under the EC Urban Waste Water Treatment Directive 

(UWWTD) and Nitrates Directive (ND)_____________________________________ 18

4.3 Assessment of Transboundary Transport of Nutrients _________________ 20

5 Comparisons with European eutrophication related policies ___________________ 48

6 Perspectives __________________________________________________________ 49

6.1 Measures taken to address UK Problem Areas and Potential Problem Areas __ 49

6.1.1 Problem Areas and potential Problem Areas designated in 2002 _________________49

6.1.2 Measures taken to reduce the inputs of Nutrients from UK Problem Areas and Potential 

problem areas________________________________________________________________50

6.2 Outlook_________________________________________________________ 52

6.2.1 Expected trends _______________________________________________________52

6.2.2 Improvement of assessments _____________________________________________55

7 Conclusions on the Eutrophication Status of UK Seas________________________ 57

8 References ___________________________________________________________ 62

9 Annexes _____________________________________________________________ 63

9.1 Screening Review ________________________________________________ 63

9.2 Thresholds used in the OSPAR comprehensive procedure_______________ 65
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Table of figures and tables 

Figure 1: Areas submitted to the 2008 Screening Review ........................................................................6

Figure 2: Outcome of the 2008 Screening Review; areas with nutrient concentrations at background 

levels were designated as Non-Problem (green) and assessed no further. Remaining areas (blue) 

were submitted to full assessment under the Comprehensive Procedure (CP).................................7

Figure 3: Cefas SmartBuoy locations in the southern North Sea (Gabbard and Warp) and Liverpool 

Bay .................................................................................................................................................15

Figure 4: Sampling sites; sites were matched to OSPAR areas for assessments. ...................................16

Figure 5: Final classification for UK assessment areas. .........................................................................60

Figure 6: Map extracts of assessment areas in (a) Scotland, (b) Northern Ireland, and (c) English south 

coast................................................................................................................................................61

Table 1: Assessment parameters and description of thresholds for the 2008 OSPAR Comprehensive 

procedure........................................................................................................................................11

Table 2: Evaluation of Risk of Nutrient Enriched Waters scoring “ + - -“ to Problems Elsewhere 21 

 

Table 3: UK results of the OSPAR Comprehensive Procedure Assessment 2008. ................................23

Table 4: UK Problem Areas and Potential Problem Areas reported to OSPAR in first application of the 

Comprehensive Procedure in 2002; sensitive areas (SA) under the UWWT Directive and nitrate 

vulnerable zones (NVZ) under the Nitrates Directive ....................................................................49

Table 5: Expected Eutrophication Status of UK waters examined under the OSPAR 

 Comprehensive Procedure 54 

Table 6 Final classification of UK areas.................................................................................................59

Table 7: Summary results of the 2008 screening procedure for England and Wales. Data were 

separated into spatial and temporal.................................................................................................63

Table 8: Summary of phytoplankton indices (IE) relating to the occurrences of elevated taxa counts 

within a whole population ..............................................................................................................65

Table 9: Thresholds for assessment of macroalgae blooms under the OSPAR CP ................................65

Table 10: Proposed dissolved oxygen standards for naturally ventilated layers (or rapidly exchanged 

stratified waters) of transitional and coastal waters........................................................................66

Table 11: Assessment criteria for Category IV – occurrence of toxicity in bivalve mollusc tissue and 

presence of toxin producing algae. .................................................................................................67
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1 Introduction 

This report presents the outcome of the second application of the Comprehensive Procedure 

assessment to OSPAR maritime waters in the jurisdiction of the United Kingdom. The 

purpose was to assess the status of waters, on the basis of a harmonised set of assessment 

criteria to provide an initial classification and, using further supporting evidence, to produce a 

final classification, as either Non Problem Area or Problem Area with respect to 

eutrophication. Where there was uncertainty a further assessment category of Potential 

Problem Area has been assigned. 

The first application of the Common Procedure in 2002 applied the agreed Screening 

Procedure to define obvious Non Problem Areas and focused attention and resources on those 

areas to which the Comprehensive Procedure was subsequently applied. In line with the spirit 

of the agreement (but not formal requirement) the UK carried out a further screening review 

in the light of known changes and our developing understanding of overall ecological status to 

conclude on the areas to which the Comprehensive Procedure would be applied. 

A thorough review was undertaken of the thresholds applied for each of the Harmonised 

Assessment Criteria, taking account of regional differences where this was required, lessons 

learned from the first application and national developments in the field of eutrophication 

assessment, including work with respect to European Directives. Where it is scientifically 

justified, we have used similar thresholds across the wide variety of water types in the UK 

area for simplicity and transparency. 

The UK assessment follows the Comprehensive Procedure Guidance as closely as possible 

but in the light of the characteristics of UK waters, we have deployed methods that are 

considered to be more rigorous and improve the quality of the assessment. This is made clear 

in the report. 

It is important to ensure that the methodology has been applied well and that the conclusions 

are based on robust and reliable evidence. To ensure that this is the case the area based 

assessments have been subject to an open peer review process. Three international experts, 

led by Prof Paul Tett (Napier University), were commissioned to undertake the review, which 

concluded with a public workshop challenging all aspects of the work. The key findings of 

the review have been incorporated into this report either as changes to overall classification 

where this was based on evidence or changes affecting the robustness and level of confidence 

in the classification. The evaluators suggested some improvements to the Comprehensive 
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Procedure assessment approach which will be submitted separately to OSPAR for 

consideration (the issues are summarised later in this report) and also proposed changes 

towards greater consistency of approach across the UK which will be taken up by the national 

authorities. Findings from the evaluators report will be submitted to OSPAR EUC, for 

information. 

We have not included a specific chapter on the implementation of the integrated set of 

EcoQOs for eutrophication. The UK believes that the overall assessment provided by the 

application of Comprehensive Procedure provides the relevant information with respect to 

ecosystem health and is the most appropriate assessment to target the development of any 

measures which might be needed. 

The first application of the Comprehensive Procedure resulted in identification of most of the 

UK maritime area as Non Problem Area status with 12 estuaries/embayments identified as 

Problem Areas and 4 estuaries/embayments as Potential Problem Areas. There were 5 Non 

Problem Areas downstream of catchments with a size of population and/or level of 

agricultural activity that were of continuing interest and required monitoring to assure their 

continuing NPA status. These areas are highlighted in the assessment (Table ). The overall 

UK eutrophication monitoring programme was modified providing additional surveillance in 

particular areas of concern. 

The results of this second application of the Comprehensive Procedure, which broadly 

confirm those of the first application, can be found in Chapter 7 and in summary form in 

Table 6, on page59. 

The detailed results within the maritime jurisdiction of the UK are presented in a series of 

separate area reports, which are available electronically from the following link: 

www.cefas.co.uk/ospardocs. 
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2 Description of assessed areas 

Figure 1: Areas submitted to the 

2008 Screening Review 

A screening review was undertaken to provide assurance that areas previously identified as 

obvious Non Problem Areas (NPA) through application of the Screening Procedure in 2002 

were still NPAs; taking account of any known changes in pressures and through a simple 

evaluation based on a comprehensive, quality assured database of winter nutrient 

concentrations (Section 9.1, Annexes). The areas submitted to the screening review are 

shown in Figure 1. The review confirmed the previous assessment and further identified that 

waters in the North Sea to the east of Scotland could also be excluded from the 

Comprehensive Procedure Assessment due to nutrient concentrations being near background 

and no identified risks of significance. 

The areas identified for assessment included specific estuaries and embayments (transitional 

waters – TW), areas of coastal water with significant freshwater input and offshore areas, 

either well mixed or seasonally stratified. Sub-division of these wider sea areas is on the 

basis of a good understanding of ecological type. Boundaries are also set on the basis of 

national jurisdiction e.g. the median line in the North Sea and Channel. The UK assessment 

areas are shown in Figure 2. 

 
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Figure 2: Outcome of the 2008 Screening Review; areas with nutrient concentrations at 

background levels were designated as Non-Problem (green) and assessed no further. 

Remaining areas (blue) were submitted to full assessment under the Comprehensive 

Procedure (CP). 
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Where we have identified some large sea areas for assessment and to ensure that any 

problems are not overlooked (reflecting that many such problems are closely associated with 

nutrient enriched freshwater inputs), we have carried out the assessment of waters within each 

area on the basis of salinity gradients, which result from the mixing of freshwater and 

seawater. These are presented in terms of three salinity regimes, but each assessment area 

will have a dominant salinity regime that is the basis for overall assessment. The salinity 

regimes are: 

 

• Estuarine: All areas – salinity range 0 – <30.0 

• Coastal: Irish Sea – salinity range 30 – 34.0 

North Sea – salinity range 30 – 34.5 

• Offshore: Irish Sea – salinity range > 34.0 

North Sea – salinity range >34.5 

Some of the UK estuaries/embayments have also received prior assessment of eutrophication 

status for the purposes of the EC Urban Waste Water Treatment (UWWT) Directive and 

Nitrates Directive (ND). Where these assessments have resulted in designation as a Sensitive 

Area (eutrophic) or Polluted Water (eutrophic) then they are deemed, subject to confirmation, 

to be either OSPAR Problem Areas or OSPAR Potential Problem Areas. 
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3 Methods and data 

The UK assessment follows the Comprehensive Procedure Guidance as closely as possible, 

but in the light of the characteristics of UK waters and national development of methods that 

will be used for the Water Framework Directive classification, we have deployed methods 

that are now considered to be more rigorous and improve the quality of the assessment. The 

developments are for chlorophyll, phytoplankton indicators, macrophytes (including 

macroalgae) and oxygen (see Section 4.1). 

3.1 Criteria for the OSPAR Comprehensive Procedure assessment 

The UK application of the assessment criteria and a detailed description of the assessment 

parameters for the categories is summarised in Table 1 (page 11). 

Category I: Degree of Nutrient Enrichment. Each of the Harmonised Assessment Criteria 

for Category I has been applied according to the CP Guidance. Riverine Input and Direct 

Discharge (RID) information is utilised for areas that are adjacent to the coast. Nutrient 

concentration information focuses on winter dissolved inorganic nitrogen (DIN = NO2 + NO3

+ NH4) as the primary criterion and is used in each assessment area/salinity regime, 

normalised to the relevant salinity. We have not used winter dissolved inorganic phosphorus 

as a primary criterion, unless assessment of the winter DIN/DIP (DIP = dissolved inorganic 

phosphorous) ratio suggests phosphorus limitation. We have not found such cases. 

Category II: Direct Effects of Nutrient Enrichment. Harmonised Assessment Criteria 

have been subject to detailed national scrutiny (also in association with work-streams to 

implement the Water Framework Directive) and the following specific approaches for this CP 

Assessment have been developed. Chlorophyll is assessed using the 90th percentile for the 

March to September growing season, which will inevitably include high spring-bloom 

chlorophyll values and this is why the 90th percentile (rather than the 95th percentile, for 

example) was set. We have also reported the mean and maximum levels for comparison. We 

do not think it sensible to assess against maximum levels, as they are difficult to sample, even 

where we have deployed continuous observing equipment. Instead of a set of individual 

‘phytoplankton indicator species’ we have deployed an index, which includes measures of 

Phaeocystis spp. and any phytoplankton taxa with abundance over a defined threshold. This 

is to provide a better assessment of disturbance of the phytoplankton as a result of nutrient 

enrichment. Areas where macrophytes are significant have been assessed using a specific 

index including the area covered and biomass of opportunistic macroalgal taxa. This national 
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development is being considered for adoption by the Intercalibration Process for the Water 

Framework Directive. 

The peer reviewers and our scientists have concerns that the mix of parameters and their 

formulation in Category II, confuse two aspects of the assessment of eutrophication status and 

can lead to an incorrect classification in the initial assessment. This issue is considered below 

(section 6.2.2) 

Category III Harmonised Assessment Criteria follow such guidance as exists. We have 

compared dissolved oxygen concentrations against established thresholds and made best use 

of any evidence of fish kills and the available widely distributed data on changes to benthic 

invertebrates. We have not used information about organic carbon/organic matter – there are 

few depositional areas in UK waters where this would be relevant, though it may be relevant 

in some restricted circulation areas such as small estuaries and lochs, but is not a parameter 

routinely included in our monitoring programmes. 

Category IV Harmonised Assessment Criterion has been supplemented (in coastal and 

estuarine regions) with information about the frequency of toxin producing algae (TPA) in 

water samples, assessed against thresholds established for food safety. These data have been 

collated as of interest but due to the lack of a clear scientific case linking nutrient enrichment 

with either the presence or proliferation of TPA, or their presence in bivalve mollusc tissue, 

we have given these parameters no weighting in our assessment. There is evidence from the 

Atlantic coasts of the UK that the presence and proliferation of TPA and/or incidence of 

toxicity in bivalve mollusc tissue result from factors other than nutrient enrichment. This will 

be the subject of further investigation. 

Harmonisation: In developing the approaches and thresholds to be applied on a regional 

basis the UK has, as far as possible, harmonized with UK national programmes set up to 

implement the Water Framework Directive which follow the recommendations for assessment 

levels agreed by the North East Atlantic Geographical Inter-calibration Group. The UK has 

also noted that some Contracting Parties bordering the North and Irish seas use thresholds, of 

a similar order for nitrogen and chlorophyll, giving confidence that assessments of similar 

offshore and coastal waters are being carried out on a comparable basis. 
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April 2008 

Table 1: Assessment parameters and description of thresholds for the 2008 OSPAR Comprehensive procedure. 

Assessment Parameters Description 

Category I. Degree of nutrient enrichment (causative factors); 1. Riverine inputs and direct discharges (area specific) 

Annual inputs for each year assessed (displayed as bar chart) for direct receiving arealongest time series available. An increasing trend scores +.

2. Nutrient concentrations (area specific) Elevated level(s) of winter DIN and/or DIP 

The winter period defined as November – February inclusive. Thresholds for nutrienfreshwater end point (42 μM, S = 0) and marine reference concentration (10 μM, S = normalised to any specific salinity. For example, North Sea Winter DIN thresholds – relative to salinity/area1. 

Estuary – normalised to salinity of 25. Ref value = 20 μM; + 50% = threshold 

Coastal – normalised to salinity 32. Ref value = 13 μM; + 50 % = threshold o

Offshore 2 – normalised to salinity 34.5 Ref value = 10 μM; + 50 % = thresho

P is assessed as part of the N/P ratio (see assessment parameter 3, below). Winter DIunless P limitation indicated because of its complex behaviour in estuaries and areas Notes 

1 Threshold values are presented for two nominal ranges of salinity. Assessments can 

the reference dilution line 

2For Irish Sea – more appropriate to use >34 for offshore waters

3. N/P ratio (area specific) Elevated winter N/P ratio (Redfield N/P = 16) 

Significant deviation (>50%) from Redfield ratio based on annual winter average nut

N:P 24:1 (Additional information may be supplied for N:Si 2:1) Notes 

1Ratios are calculated for each sample and averaged over the assessment area. (SE ca

Category II. Direct effects of nutrient enrichment; 
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April 2008 

Assessment Parameters Description 

1. Chlorophyll concentration (area specific) • Elevated percentile, 

90th percentile for period March – September (reflects WFD European Intercalibratio

Thresholds 

Estuarine – 15 μg l-1

Coastal – 15 μg l-1

Offshore – 10 μg l-1

Mean and maximum concentrations are also reported as supporting evidence.

2. Phytoplankton indicators (area specific) 

• Elevated levels of 

phytoplankton species (and increased duration of blooms) 

Phytoplankton assessment using new phytoplankton index approach based on: Total cell count – assessment of occurrences over 107 

Phaeocystis cell count – occurrences over 106 Any single taxa – occurrences over 106 Chlorophyll concentrations – occurrences exceeding 10 μg l-1Threshold set on all exceedance counts being less than 25% of all sampling times Description of index This index is designed to assess if the presence, abundance and frequency of occurrespecies correspond to undisturbed conditions. The tool is composed of four attributesfrequency that elevated biomass [chl] exceeds a reference threshold and three of whicthat may result in the decline of ecosystem health or result in an undesirable disturban

works by recording the number of events, defined by sampling occasions when the suexceeds these predefined thresholds over the period of the monitoring programme. Eafrom the number of times that the sub-metric exceeds the threshold as a proportion of times and calculated as a six year mean. Final classification score is based on the mea%). The UK believes that this index, which is being developed for Water Framework Dirbetter assessment of phytoplankton species than just looking at individual species. 
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April 2008 

Assessment Parameters Description 

The index is described in detail in: Marine Pollution Bulletin 55 (2007) 91–103 

3. Macrophytes including macroalgae (are specific) 

Shift from long-lived to short-lived opportunistic species (e.g. Ulva) 

Thresholds recommended for macroalgal biomass and area coverage based on those d

Category III. Indirect effects of nutrient enrichment (during growing season); 

1.Oxygen deficiency • Decreased levels (< 4 

mg l-1) and lowered 

% oxygen saturation 

The assessment levels that are used are concentrations measured below 4 mg l-1 to jud

as an undesired oxygen deficiency level for each area 

• Assessment will be for period of summer/autumn (May – September) • 5%ile thresholds. 
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April 2008 

2. Zoobenthos and fish 

• Kills (in relation to 

oxygen deficiency and/or toxic algae) 

• Long term areaspecific changes in 

zoobenthos biomass and species composition 

Incidence of fish kills or documented changes in zoobenthos will be presented to asseto eutrophication. 

3. Organic Carbon/Organic Matter 

Not applied in UK waters unless sedimentation area identified and data available. 

Category IV. Other possible effects of nutrient enrichment. 

1. Incidence of DSP/PSP mussel infection events 

Incidence of toxicity in bivalve mollusc tissue e.g. DSP or PSP mussel infection even

in excess of FSA limits. Additional assessment based on analysis of Toxin Producing Algae (TPA) in water saoccurrence should be below the FSA limits. 
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3.2 Inventory of available data 

Data used in this assessment are provided by the UK National Marine Monitoring Programme 

(NMMP), which implements the OSPAR Co-ordinated Environmental Monitoring 

Programme for Eutrophication, together with data collected for other assessments of 

eutrophication status. The majority of UK marine waters were classified under the 2002 

application of the Comprehensive Procedure as Non-Problem Areas which limits the NMMP 

data collection to winter nutrient concentrations. However, the 2002 application of the CP 

identified areas of particular continuing interest that required ongoing monitoring, including 

the East England, East Anglia, Liverpool Bay, Solent and the Clyde, and these have been 

sampled for all relevant harmonised assessment criteria, and in several cases have undergone 

intense surveillance using in-situ sampling equipment (SmartBuoys) or specifically 

commissioned surveys by the Environment Agency. The Cefas SmartBuoy sites are shown in 

Figure 3. 

Figure 3: Cefas SmartBuoy locations in the southern North Sea (Gabbard and Warp) 

and Liverpool Bay 

Further monitoring and research have been carried out in support of European Directives and 

through national/international research programmes to provide a rich and well distributed set 

of relevant data (Figure 4) 
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Figure 4: Sampling sites; sites were matched to OSPAR areas for assessments. 

Time Period for Data Collection

Monitoring information for the period 2001 – 2005 has been used for most of the areas 

assessed. There are some areas where, for some parameters, adequate (in quantity or quality) 

data were not available and this has caused us to assign a lower confidence to the parameter 
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assessment. Time series information exists for several parameters extending well beyond the 

assessment period. These data have been included in assessment of trends. 

Adequacy of the Data and Confidence in the Assessment 

The data sets are generally ‘fit for purpose’ providing adequate spatial coverage and temporal 

resolution to carry out a good assessment. However, there are variations in data coverage 

between areas, reflecting the level of perceived risk and the practicalities of monitoring, and 

between the different parameters where, for example, there are more data available for winter 

nutrient concentrations and chlorophyll than for phytoplankton species. The adequacy of the 

data is reflected in the confidence with which we are able to reach conclusions about the 

status of each area. Included in the classification table (Table , page23) is an assessment of 

our confidence for each of the three aspects of eutrophication classification – nutrient 

enrichment, accelerated growth and undesirable disturbance – and our overall confidence in 

the area classification. 

We have made best use of all available data that meet strict quality assurance criteria to carry 

out the area-based assessments. The data sets are summarised in Appendix I and are itemised 

in detail in each area assessment report. 
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4 Eutrophication assessment 

4.1 Outline of assessment process 

The assessment process follows the 3 steps of the Comprehensive Procedure Guidance. 

 Step 1 is to select and apply relevant parameters from the table of Harmonised Assessment 

Criteria to the area being assessed. This requires the collation of appropriate data sets for the 

area and the application, as required, of the relevant statistical treatment to produce a score to 

show whether or not the criterion has been exceeded (designated by a + or – for each 

criterion). The respective thresholds for the parameters in UK waters have been highlighted 

in Table 1 Step 2 uses a common format, based on the four categories of assessment criteria, 

to arrive at an initial classification for the area. Examples of how the combination of scores 

produces the initial classification are given in the Common Procedure guidance (OSPAR 

2005-3, Section 5, Table 2). 

 Step 3 is an appraisal of all relevant information (concerning the harmonised assessment 

criteria, their respective assessment levels and the supporting environmental factors) to 

provide a sufficiently sound and transparent account of the reasons for assigning a particular 

status to an area. This leads to the final classification of the status of the area. 

The results of the application of the Comprehensive Procedure to areas within the maritime 

jurisdiction of the UK are presented in a series of separate area reports, which provide the 

detailed evidence on which the overall classification is based. These reports are available 

electronically from the following link: www.cefas.co.uk/ospardocs. Table provides a 

summary of the outcome of these assessments in the overall classification format described in 

Annex 5 of the Common Procedure Guidance (OSPAR 2005-3). 

4.2 Assessment under the EC Urban Waste Water Treatment Directive (UWWTD) 

and Nitrates Directive (ND) 

Relevant UK estuaries and coastal waters have received prior assessment of eutrophication 

status for the purposes of the UWWTD and ND. Most estuaries have been assessed and 

where there is a weight of evidence showing an undesirable disturbance resulting from 

nutrient enrichment, designation as Sensitive Waters (eutrophic) and/or identification of 

Polluted Waters (eutrophic) has occurred. These designations are deemed to be either 

Problem Areas or Potential Problem Areas with respect to eutrophication for the purposes of 

the Comprehensive Procedure Assessment but have not, for England and Wales, been 

separately assessed using the OSPAR methodology. To check the comparability of the 
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different assessments, the OSPAR Comprehensive Procedure has been applied to areas 

designated as Sensitive Water (eutrophic) and Polluted Waters (eutrophic) in Scotland and 

Northern Ireland. The methods are found to be broadly comparable resulting in equivalent 

classification of eutrophication status. 

For Northern Ireland we have relied on existing robust assessments to come to a conclusion 

about status which has already driven management action in several cases. The assessment 

for some Northern Ireland areas has been updated but, as noted by the peer evaluators, there 

remains a mis-match with regard to the period for which data is reported and the assessment 

period for the application of the Comprehensive Procedure. 
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4.3 Assessment of Transboundary Transport of Nutrients 

The OSPAR Comprehensive Procedure points out Contracting Parties should take into 

account the risk that nutrient inputs may be transferred to adjacent areas where they can cause 

detrimental environmental effects and Contracting Parties should recognise that they may 

contribute significantly to problem areas and potential problem areas with regard to 

eutrophication outside their national jurisdiction. The UK has made the following assessment 

of this risk and of the associated footnotes in Table 2 of the Comprehensive Procedure. 

Footnote 9 in table 2, which refers to those areas with nutrient enrichment but no other effects 

(i.e scoring +--) states that: “The increased degree of nutrient enrichment in these areas may 

contribute to eutrophication problems elsewhere” 

Areas in the UK with this “+--“ score are: the North East Irish Sea, Liverpool Bay, the Bristol 

Channel, the Solent, the Eastern English Channel, the Clyde Estuary, the Tay Estuary, the 

Eden Estuary and Carlingford Lough. 

The UK has looked at these assessment areas and, on the basis of current knowledge, does not 

believe that the transport of nutrients (nitrogen and phosphorus) from these areas will give 

rise to undesirable disturbance in the waters of other Contracting Parties. 

This evaluation is based on 

3⁄4 Knowledge of general circulation and flows from the areas concerned 

3⁄4 Transport from coastal to offshore waters within the UK maritime area 

3⁄4 The scores for nutrient enrichment in the waters of other Contracting Parties given in 

their national asessments 

3⁄4 Reflection on the strength of assessment based on specific assessment parameters 

employed by other Contracting Parties e.g. Phytoplankton Indicator Species 

3⁄4 Current information from modelling activities 

The main findings of the evaluation are summarised in Table 2 below. More information is 

available in the UK area reports. Futhermore the UK is leading the OSPAR modelling work 

on transboundary transport which should give further information on this issue, particularly 

for North Sea areas in the next couple of years. When this modelling exercise is completed, 

the UK will see if this risk evaluation needs to be revised. 
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Table 2. Evaluation of Risk of Nutrient Enriched Waters scoring “ + - -“ to 

Eutrophication Problems Elsewhere 

Areas with 

(+ - -) initial 

scores 

Adjacent 

area 

Adjacent 

area status 

Possible 

recipient 

areas 

further 

away 

Remote 

Area 

status 

Supporting 

Information 

Evaluation of 

risk of 

contribution to 

eutrophication 

problems 

elsewhere 

Bristol 

Channel 

Celtic Sea 

(UK) 

Non 

Problem 

Area 

(screened) 

Irish Sea 

 (UK and 

Ireland) 

Non 

Problem 

Area 

(screened) 

Ireland has no 

Problem Areas in 

possible recipient 

waters. Ireland has 

confirmed it does 

not see UK nutrients 

as a risk to 

eutrophication 

status. 

Minimal 

Liverpool 

Bay 

North East 

Irish Sea 

Non 

Problem 

Area 

Irish Sea 

(UK and 

Ireland) 

Non 

Problem 

Area 

(screened) 

Ireland has no 

Problem Areas in 

possible recipient 

waters. Ireland has 

confirmed it does 

not see UK nutrients 

as a risk to 

eutrophication 

status. 

Minimal 

NE Irish Sea Irish Sea Non 

Problem 

Area 

(screened) 

Irish Sea 

(Ireland) 

Non 

Problem 

Area 

(screened) 

Ireland has no 

Problem Areas in 

possible recipient 

waters. Ireland has 

confirmed it does 

not see UK nutrients 

as a risk to 

eutrophication 

status. 

Minimal 

Carlingford 

Lough 

Northern 

Ireland 

and 

Ireland 

Coastal 

Waters 

Non 

Problem 

Area 

(screened) 

Irish Sea 

(UK and 

Ireland) 

Non 

Problem 

Area 

(screened) 

Ireland has no 

Problem Areas in 

possible recipient 

waters. Ireland has 

confirmed it does 

not see UK nutrients 

as a risk to 

eutrophication 

status. 

Minimal 

Solent 

Coastal 

Water 

East 

English 

Channel 

Coastal 

Water 

Non 

Problem 

Area (+ - - 

) 

Southern 

North Sea 

offshore 

UK 

Belgium 

Netherlands 

Non 

Problem 

Area (- - -) 

Potential 

Problem 

Area (- - -) 

Problem 

Area (- + 

+) 

Minimal 

East English 

Channel 

Coastal 

Water 

East 

English 

Channel 

Offshore 

Water 

Non 

Problem 

Area (- - - ) 

Southern 

North Sea 

offshore 

UK 

Belgium 

Non 

Problem 

Area (- - -) 

Potential 

Problem 

Area (- - -) 

Problem 

No positive scores 

for nutrient 

enrichment, lack of 

harmonisation of 

chlorophyll 

thresholds, weak 

evidence of 

undesirable 

disturbance in 

possible recipient 

PPAs and PAs.1

 

1

 Some countries have still not finalised their assessment thresholds (as at February 2008) 
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Areas with 

(+ - -) initial 

scores 

Adjacent 

area 

Adjacent 

area status 

Possible 

recipient 

areas 

further 

away 

Remote 

Area 

status 

Supporting 

Information 

Evaluation of 

risk of 

contribution to 

eutrophication 

problems 

elsewhere 

Netherlands Area (-+ +) 

Minimal 

Clyde 

Estuary 

Outer 

Firth of 

Clyde 

Non 

Problem 

Area (- - -) 

West of 

Scotland 

Costal 

Waters 

Non 

Problem 

Area 

(screened) 

Transport of 

nutrients in 

significant amounts 

to waters of other 

OSPAR countries 

unlikely 

Minimal 

Tay Estuary East of 

Scotland 

Coastal 

Waters 

Non 

Problem 

Area 

(screened) 

North Sea 

offshore 

(UK, 

Denmark, 

Norway) 

Non 

Problem 

Area 

Minimal 

Eden 

Estuary 

East of 

Scotland 

Coastal 

Waters 

Non 

Problem 

Area 

(screened) 

North Sea 

offshore 

(UK, 

Denmark, 

Norway) 

Non 

Problem 

Area 

There is no evidence 

of enhanced 

nutrients in adjacent 

coastal waters so 

impacts on the 

waters of other 

OSPAR countries is 

unlikely2

. 

Minimal 

Footnote 8 in table 2 of the Comprehensive Procedure , which refers to those areas classified as 

problem areas scoring “-++”, “-+-“ or “--+” which may be caused by transboundary transport of 

(toxic) algae and/or organic matter arising from adjacent/remote areas. The UK does not have any 

assessment areas which have these scores, and therefore concludes that transboundary transport of this 

nature is not responsible for eutrophication problems in UK waters. 

 

2

 A study of the relative importance of riverine nutrient inputs to the Scottish North Sea Coastal Zone. 

Marine Pollution Bulletin, Volume 26, Issue 11, November 1993, Pages 620-628
National Report on the Eutrophication Status of UK waters 

April 2008 

Table 3: UK results of the OSPAR Comprehensive Procedure Assessment 2008. 

Key to the table 

NI Nutrient inputs (riverine and direct discharges total N and total P) DI Dissolved nutrients (Winter DIN and/or DIP concentrations) NP Increased winter N/P ratio Ca Maximum and mean Chlorophyll a concentration Ps Region/area specific phytoplankton indicator species 

Mp Macrophytes including macroalgae O2 Degree of oxygen deficiency 

Ck Changes/kills in zoobenthos and fish kills Oc Organic carbon/organic matter At Algal toxins (DSP/PSP mussel infection events) 

+ = - = ? = 
National Report on the Eutrophication Status of UK waters 

April 2008 

Area 

Category I 

Degree of nutrient 

enrichment 

Category 

II 

Direct 

effects 

Category III and IV 

Indirect effects/ other 

possible effects 

Initial classifican

Appraisal of all relevant information (conceassessment criteria their respective assessmesupporting environmental factors). The leve

the evidence used to assess the various catconclusion are also given (see section 3.2 f

NI Ca - O2 - At DI - Ps Ck - 

Northern North Sea 

NP - Mp Oc 

NPA 

• There is strong evidence that the area is 

confidence). Although this is based on conclusion is confirmed by taking accodata and a published climatology report (

• There is evidence that there is no acc

confidence). The chlorophyll 90th percen

years and the modified green test is also confirmed by taking account of ICES report.

• The available evidence does not su

undesirable disturbance (low confidence)

The final classification of the area is a Non Pconfidence), based on the lack of nutrient enaccelerated growth and evidence that there idisturbance to the biology or water quality. 
National Report on the Eutrophication Status of UK waters 

April 2008 

Area 

Category I 

Degree of 

nutrient 

enrichment 

Category 

II 

Direct 

effects 

Category III and IV 

Indirect effects/ other 

possible effects 

Initial classifican

Appraisal of all relevant information (conceassessment criteria their respective assessmesupporting environmental factors). The leve

the evidence used to assess the various catconclusion are also given (see section 3.2 f

NI Ca - O2 - At DI - Ps Ck - 

Southern North Sea 

NP - Mp Oc 

NPA 

• There is no nutrient enrichment (high co

extensive measurements from SmartBudata. 

• There is evidence of no accelerated grow

High intensity sampling has shown that 90th percentiles in waters of >34.5 salinthreshold. 

• The evidence available suggests that the

disturbance (medium confidence). Meaconsistently > 4 mg l-1, there was no det

zoobenthos community and there was a

The final classification of the Southern NortArea (high confidence). The results show thenrichment, accelerated growth or undesirab
National Report on the Eutrophication Status of UK waters 

April 2008 

Area 

Category I 

Degree of 

nutrient 

enrichment 

Category 

II 

Direct 

effects 

Category III and IV 

Indirect effects/ other 

possible effects 

Initial classifican

Appraisal of all relevant information (conceassessment criteria their respective assessmesupporting environmental factors). The leve

the evidence used to assess the various catconclusion are also given (see section 3.2 f

NI - Ca + O2 - At - DI + Ps - Ck - 

Eastern English Coast (area of particular continuing interest) 

NP + Mp - Oc 

PA 

Following the 2002 application of the Comparea was subject to enhanced monitoring and • There is nutrient enrichment (high conf

exceeding the threshold. 

• There is evidence of accelerated growth 

chlorophyll 90th percentiles exceeded th

with sufficient data. However, the meathreshold in all years, except 2004. 

• There is evidence of no undesirable dist

The phytoplankton indicator was below was no excessive opportunistic macroalconsistently > 4 mg l-1. The zoobenthos 

change, there were no reported fish kills mollusc tissue. 

The final classification of the area is a Non Pconfidence) based on evidence that in spite oaccelerated growth, there high confidence thundesirable disturbance, and that PA status i
National Report on the Eutrophication Status of UK waters 

April 2008 

Area 

Category I 

Degree of 

nutrient 

enrichment 

Category 

II 

Direct 

effects 

Category III and IV 

Indirect effects/ other 

possible effects 

Initial classifican

Appraisal of all relevant information (conceassessment criteria their respective assessmesupporting environmental factors). The leve

the evidence used to assess the various catconclusion are also given (see section 3.2 f

NI - Ca + O2 - At - DI + Ps - Ck - 

East Anglia (area of particular continuing interest) 

NP + Mp - Oc 

PA 

Following the 2002 application of the Comparea was subject to enhanced monitoring and • The area is nutrient enriched (high conf

exceeding the threshold in most years. 

• The area is assessed as showing signs o

(medium confidence). Chlorophyll 90th 

threshold in 30 – 34.5 salinity, but were >34.5. 

• The area exhibits strong evidence of no 

(high confidence). The phytoplankton imacroalgal growth levels were below thconsistently > 4 mg l-1. The zoobenthos 

change and there were no reported fish incidents of toxicity in bivalve mollusc 

The final classification is of a Non Problem confidence), because in spite of nutrient enrigrowth, there is high confidence that there is undesirable disturbance, and that PA status i
National Report on the Eutrophication Status of UK waters 

April 2008 

Area 

Category I 

Degree of 

nutrient 

enrichment 

Category 

II 

Direct 

effects 

Category III and IV 

Indirect effects/ other 

possible effects 

Initial classifican

Appraisal of all relevant information (conceassessment criteria their respective assessmesupporting environmental factors). The leve

the evidence used to assess the various catconclusion are also given (see section 3.2 f

NI Ca - O2 - At - DI + Ps - Ck - 

Northeast Irish Sea 

NP - Mp - Oc 

NPA 

• The area is assessed as showing evidenc

(low confidence). Winter DIN exceede5 years but N/P ratios did not. 

• The area is assessed as showing evidenc

(high confidence) as chlorophyll 90th pe

<15 μg l-1. 

• The area is assessed as showing evidenc

disturbance (high confidence). Phytoplexceed thresholds. DO was consistently 

recorded fish kills and zoobenthos data change in community structure. There toxicity in bivalve mollusc tissue. 

The final classification is of the northeast IriArea (high confidence), based on evidence tenrichment, there was no evidence of acceleundesirable disturbance. 
National Report on the Eutrophication Status of UK waters 

April 2008 

Area 

Category I 

Degree of 

nutrient 

enrichment 

Category 

II 

Direct 

effects 

Category III and IV 

Indirect effects/ other 

possible effects 

Initial classifican

Appraisal of all relevant information (conceassessment criteria their respective assessmesupporting environmental factors). The leve

the evidence used to assess the various catconclusion are also given (see section 3.2 f

NI - Ca - O2 - At - DI + Ps - Ck - 

Liverpool Bay (area of particular continuing interest 

NP - Mp - Oc 

NPA 

Following the 2002 application of the Comparea was subject to enhanced monitoring and • This area is assessed as showing eviden

(high confidence). Winter DIN exceedeDIN/DIP ratios did not. 

• The area is assessed as showing evidenc

(medium confidence). The chlorophyll 

μg l-1 in 2004, but <15 μg l-1 in more re

• There is evidence of no undesirable dist

The phytoplankton indicator was below would not favour flagellate growth. Theblooms above the threshold. DO was co

zoobenthos showed no evidence for chareported fish kills. There were no incidmollusc tissue. 

The final classification is of a Non Problem based on evidence that in spite of nutrient enevidence that there was no accelerated growdisturbance. 
National Report on the Eutrophication Status of UK waters 

April 2008 

Area 

Category I 

Degree of 

nutrient 

enrichment 

Category 

II 

Direct 

effects 

Category III and IV 

Indirect effects/ other 

possible effects 

Initial classifican

Appraisal of all relevant information (conceassessment criteria their respective assessmesupporting environmental factors). The leve

the evidence used to assess the various catconclusion are also given (see section 3.2 f

NI - Ca - O2 - At - DI + Ps - Ck - 

Bristol Channel 

NP + Mp - Oc 

NPA 

• The area is assessed as nutrient enriched 

Winter DIN and DIN/DIP ratios exceedyears with sufficient data. 

• The area is assessed as showing evidenc

(high confidence), with chlorophyll 90th 

threshold. 

• Bristol Channel is assessed (high confid

of no undesirable disturbance. The phyopportunistic macroalgal growth levels thresholds. DO was consistently > 4 mg 

showed no evidence for change and thekills. There were no incidents of toxicittissue. 

The final classification of the Bristol ChannArea (high confidence), based on evidence tenrichment, there is strong evidence that thegrowth or undesirable disturbance 
National Report on the Eutrophication Status of UK waters 

April 2008 

Area 

Category I 

Degree of 

nutrient 

enrichment 

Category 

II 

Direct 

effects 

Category III and IV 

Indirect effects/ other 

possible effects 

Initial classifican

Appraisal of all relevant information (conceassessment criteria their respective assessmesupporting environmental factors). The leve

the evidence used to assess the various catconclusion are also given (see section 3.2 f

NI Ca - O2 - At - DI + Ps - Ck - 

Eastern English Channel 

NP + Mp - Oc 

NPA 

• This area is assessed as showing eviden

(medium confidence). Winter DIN excwaters 30 – 34.5 salinity, but in only on

• The area is assessed as showing no evid

(low confidence). Chlorophyll 90th perc

thresholds, except in 2002 in 30 – 34.5 means were below thresholds. 

• There is evidence of no undesirable dist

confidence). Phytoplankton indices did and there were no excessive opportunistDO was consistently >4 mg l-1. There h

kills and zoobenthos data did not indicaThere were no incidents of toxicity in b

The final classification is of the east English Problem Area (medium confidence), based onutrient enrichment, there was no acceleratedisturbance. 
National Report on the Eutrophication Status of UK waters 

April 2008 

Area 

Category I 

Degree of 

nutrient 

enrichment 

Category 

II 

Direct 

effects 

Category III and IV 

Indirect effects/ other 

possible effects 

Initial classifican

Appraisal of all relevant information (conceassessment criteria their respective assessmesupporting environmental factors). The leve

the evidence used to assess the various catconclusion are also given (see section 3.2 f

NI Ca - O2 - At - DI + Ps - Ck - 

Solent (area of particular continuing interest) 

NP + Mp - Oc 

NPA 

Following the 2002 application of the Comparea was subject to enhanced monitoring and • The area is assessed as nutrient enriched 

winter DIN in waters <34.5 salinity exc

• The area assessment is of no accelerated 

confidence). Chlorophyll 90th percentil

thresholds in 5 out of 6 years. 

• The area is assessed as showing no und

(medium confidence). Phytoplankton inthresholds. DO was consistently >4mg l

and no toxicity in bivalve mollusc tissu

In conclusion, the Solent has the final classiArea (medium confidence), based on evidenenrichment, there was no accelerated growth disturbance. 
National Report on the Eutrophication Status of UK waters 

April 2008 

Area 

Category I 

Degree of 

nutrient 

enrichment 

Category 

II 

Direct 

effects 

Category III and IV 

Indirect effects/ other 

possible effects 

Initial classn

Appraisal of all relevant information (concerning the parameters, their respective assessment levels and the environmental factors). The level of confidence pla

used to assess the various categories and the overa

given (see section 3.2 for explanation).

NI - Ca - O2 - At DI - Ps ? Ck - 

Solway 

NP - Mp - Oc 

NPA 

• There are sufficient nutrient data to demonstrate 

of nutrient enrichment (high confidence). 

• There are limited data showing that chlorophyll c

exceed assessment criteria on surveys between 2low confidence in the conclusion that there is no growth. 

• There is low confidence in the lack of evidence o

disturbance, due to the limited data. The phytopqualitative rather than quantitative so the new asnot be used. However, the waters are well oxygeevidence of no fish or zoobenthos kills. 

The final assessment of the Solway is as a Non-Problconfidence), based on strong evidence of no nutrient evidence that there was no accelerated growth or und
National Report on the Eutrophication Status of UK waters 

April 2008 

Area 

Category I 

Degree of 

nutrient 

enrichment 

Category 

II 

Direct 

effects 

Category III and IV 

Indirect effects/ other 

possible effects 

Initial classn

Appraisal of all relevant information (concerning the parameters, their respective assessment levels and the environmental factors). The level of confidence pla

used to assess the various categories and the overa

given (see section 3.2 for explanation).

NI - Ca - O2 - At DI + Ps ? Ck - 

Clyde estuary (area of particular continuing interest) 

NP - Mp - Oc - 

PPA 

• There is evidence of nutrient enrichment (high co

DIN exceeded the assessment threshold. Howeveexceed the threshold. 

• There are sufficient chlorophyll data to give high 

no evidence of accelerated growth. 

• There is low confidence in the evidence of undes

very limited phytoplankton data, however the exthe criterion would not be exceeded. The low diconcentrations at the head of the estuary during sinputs of urban wastewater rather than eutrophicto show that measures taken to reduce these discincrease in diversity and abundance of zoobenthowas evidence of no fish or zoobenthos kills since 

The final assessment of the Clyde estuary is as a Nonconfidence), based on evidence that in spite of nutrienstrong evidence that there was no accelerated growth there was no undesirable disturbance. 
National Report on the Eutrophication Status of UK waters 

April 2008 

Area 

Category I 

Degree of 

nutrient 

enrichment 

Category 

II 

Direct 

effects 

Category III and IV 

Indirect effects/ other 

possible effects 

Initial classn

Appraisal of all relevant information (concerning the parameters, their respective assessment levels and the environmental factors). The level of confidence pla

used to assess the various categories and the overa

given (see section 3.2 for explanation).

NI - Ca - O2 - At - DI - Ps - Ck - 

Inner Firth of Clyde 

NP - Mp - Oc - 

NPA 

• There is no evidence of nutrient inputs increasin

winter nutrient data to give high confidence that nutrient enrichment. 

• There are sufficient summer chlorophyll data to 

that there is no evidence of accelerated growth. 

• The lack of suitable phytoplankton data gives lo

conclusion of no undesirable disturbance. Theralteration of the phytoplankton community. Mabelow the assessment criterion. The waters are there was evidence of no zoobenthos or fish killcommercial shellfish area, so there have been no events. 

The final assessment of the Inner Firth of Clyde is as (high confidence), based on strong evidence of no nuaccelerated growth and evidence of no undesirable di
National Report on the Eutrophication Status of UK waters 

April 2008 

Area 

Category I 

Degree of 

nutrient 

enrichment 

Category 

II 

Direct 

effects 

Category III and IV 

Indirect effects/ other 

possible effects 

Initial classn

Appraisal of all relevant information (concerning the parameters, their respective assessment levels and the environmental factors). The level of confidence pla

used to assess the various categories and the overa

given (see section 3.2 for explanation).

NI - Ca - O2 - At - DI + Ps - Ck - 

Forth estuary 

NP - Mp - Oc - 

NPA 

• Winter DIN exceeded the assessment criterion’s 

between 1983 and 2005, but anthropogenic nutrdecreased since 1991. The estuary is assessed as confidence). 

• Summer chlorophyll data exceeded the assessm

1997, but remained below the threshold during period, so there is no evidence of accelerated gr

• There were insufficient data to apply the phytop

assessment tool. Low dissolved oxygen concenmaximum in the upper estuary result from the dresuspended terrigenous organic matter in the wevidence of no fish kills since the early 1990s. shellfish area, so there have been no mussel infeconclusion is that there is no undesirable disturbconfidence). 

The final assessment of the Forth Estuary is as a Non(medium confidence), based on evidence that in spitthere is strong evidence that there was no accelerateshow there was no undesirable disturbance. 
National Report on the Eutrophication Status of UK waters 

April 2008 

Area 

Category I 

Degree of 

nutrient 

enrichment 

Category 

II 

Direct 

effects 

Category III and IV 

Indirect effects/ other 

possible effects 

Initial classn

Appraisal of all relevant information (concerning the parameters, their respective assessment levels and the environmental factors). The level of confidence pla

used to assess the various categories and the overa

given (see section 3.2 for explanation).

NI - Ca - O2 - At - DI + Ps - Ck - 

Tay estuary 

NP + Mp - Oc - 

NPA 

• Winter DIN exceeded the assessment criterion o

N/P ratio exceeded the threshold in saline water2000, but has not exceeded during the 2001 – 20Nutrient inputs from wastewater discharges are over the study period. The area is assessed as econfidence). 

• Chlorophyll was measured at 10 fixed stations o

the summer (June – August) in 2001 – 2005, inc

exceeded the assessment criterion in 2003 due t

peak, but was well below the assessment criterioThe area is assessed as having no accelerated gr

• It was not possible to use the quantitative assess

phytoplankton; however, qualitative assessment undesirable disturbance. There were sufficient waters are well oxygenated. There was evidencfish kills. Macroalgae growth was not extensiveevidence of undesirable disturbance (medium co

The final assessment of the Tay estuary is a Non-Proconfidence), based on evidence that in spite of nutrieno evidence of accelerated growth and undesirable d
National Report on the Eutrophication Status of UK waters 

April 2008 

Area 

Category I 

Degree of 

nutrient 

enrichment 

Category 

II 

Direct 

effects 

Category III and IV 

Indirect effects/ other 

possible effects 

Initial classn

Appraisal of all relevant information (concerning the parameters, their respective assessment levels and the environmental factors). The level of confidence pla

used to assess the various categories and the overa

given (see section 3.2 for explanation).

NI - Ca - O2 - At - DI + Ps - Ck - 

Eden estuary 

NP + Mp - Oc - 

NPA 

• Winter DIN and N/P ratios exceeded their asses

estuary is designated as enriched with nutrients 

• Chlorophyll concentrations were low as phytop

by the high flushing rate. There is low confiden

no evidence of accelerated growth, as the data a

• Estimates of macroalgal cover are limited to 200

criteria were not exceeded. The waters were wewas evidence of no zoobenthos or fish kills. Thnot appear to be modified. This is not a commethere have been no mussel infection events. Thabsence of undesirable disturbance (medium co

The final assessment of the Eden Estuary is as a Nonconfidence), because in spite of nutrient enrichment to show there was no accelerated growth and reasonthere was no undesirable disturbance. 
National Report on the Eutrophication Status of UK waters 

April 2008 

Area 

Category I 

Degree of 

nutrient 

enrichment 

Category 

II 

Direct 

effects 

Category III and IV 

Indirect effects/ other 

possible effects 

Initial classn

Appraisal of all relevant information (concerning the parameters, their respective assessment levels and the environmental factors). The level of confidence pla

used to assess the various categories and the overa

given (see section 3.2 for explanation).

NI - Ca - O2 - At - DI + Ps - Ck - 

South Esk estuary (Montrose Basin) 

NP + Mp + Oc - 

PA 

• Winter DIN and N/P ratios exceeded the assessm

considered to be nutrient enriched (high confide

• Chlorophyll concentrations were low and there 

give medium confidence in the evidence of no a

• There was no evidence of modification of the ph

community. Estimates of opportunistic green alintertidal area exceeded the assessment criterionoxygenated. There was an abundant and diverse in the intertidal area and there was evidence of nkills. This is not a commercial shellfish area, so mussel infection events. There is no evidence odisturbance (medium confidence). 

The final assessment of the South Esk estuary (MonPotential Problem Area (medium confidence), based enrichment and accelerated growth of opportunistic there is no evidence of undesirable disturbance. 
National Report on the Eutrophication Status of UK waters 

April 2008 

Area 

Category I 

Degree of 

nutrient 

enrichment 

Category 

II 

Direct 

effects 

Category III and IV 

Indirect effects/ other 

possible effects 

Initial classn

Appraisal of all relevant information (concerning the parameters, their respective assessment levels and the environmental factors). The level of confidence pla

used to assess the various categories and the overa

given (see section 3.2 for explanation).

NI - Ca + O2 - At - DI + Ps - Ck - 

Ythan estuary 

NP + Mp + Oc 

PA 

• Nitrogen concentrations in the river Ythan were 

the N/P ratio exceeded respective thresholds, in(high confidence). 

• Summer chlorophyll exceeded the assessment c• There was no evidence of modification of the ph

community. The Ythan estuary was designated Zone in 2000 on the basis of extensive growth othe intertidal area. The waters were well oxygeevidence of no zoobenthos or fish kills. This is shellfish area, so there have been no mussel infeassessment is of no undesirable disturbance (me

The Comprehensive Procedure assessment indicates 

the Ythan Estuary as a Problem Area purely on the bmay be somewhat precautionary, as although there inutrient enrichment and accelerated growth, there is no undesirable disturbance, which, overall would leanon problem area or potential problem area. 
National Report on the Eutrophication Status of UK waters 

April 2008 

Area 

Category I 

Degree of 

nutrient 

enrichment 

Category 

II 

Direct 

effects 

Category III and IV 

Indirect effects/ other possible effects 

Initial classn

Appraisal of all relevant information (conassessment parameters, their respective asssupporting environmental factors). The level the evidence used to assess the various catconclusion are also given (see section 3.2 for 

NI - Ca + O2 - At - DI + Ps ? Ck - 

Inner Belfast Lough 

NP - Mp ? Oc 

PA 

The Inner Belfast Lough was designated as a Uin 2001, and as described in section 4.2, such wautomatically designated as Problem Areas or under the OSPAR Comprehensive Procedure. uses the CP assessment to check this policy. • The Inner Lough is enriched in nutrient con

confidence), although there is evidence that 

inputs over the last five years have resulted 

• There is still some evidence of accelerated 

the chlorophyll and in-situ fluorescence dat

• There has been evidence of undesirable dis

of organisms (medium confidence). Toxincysts have been recorded in the 1990s. Therecords. DO concentrations are consistentlstep change improvement in benthic invertelinked to the reductions in organic carbon aeffluent treatment and the consequent reducfish kills have been recorded. 

With the current location of WWTW outfalls, either a Problem Area, or possibly a Potential Comprehensive Procedure in the future (high 
National Report on the Eutrophication Status of UK waters 

April 2008 

Area 

Category I 

Degree of 

nutrient 

enrichment 

Category 

II 

Direct 

effects 

Category III and IV 

Indirect effects/ other possible effects 

Initial classn

Appraisal of all relevant information (coassessment parameters, their respective assupporting environmental factors). The levethe evidence used to assess the various cconclusion are also given (see section 3.2 for 

NI - Ca - O2 - At - DI - Ps - Ck - 

Outer Belfast Lough 

NP - Mp - Oc 

NPA 

• The Outer Lough is not currently enriche

confidence). 

• There is no evidence of accelerated algal 

of a reduction in chlorophyll concentratiofrom in-situ monitoring over the last 10 yActual chlorophyll concentrations fall be2004 – 2006. 

• There is no evidence of excessive growth 

oxygen concentrations are consistently >

the critical threshold. Zoobenthos data dchange. There is no evidence of an undeconfidence). 

The final assessment of the Outer Belfast LouArea (high confidence); based on strong evidenutrient enrichment, no accelerated growth andisturbance. 
National Report on the Eutrophication Status of UK waters 

April 2008 

Area 

Category I 

Degree of 

nutrient 

enrichment 

Category 

II 

Direct 

effects 

Category III and IV 

Indirect effects/ other possible effects 

Initial classn

Appraisal of all relevant information (coassessment parameters, their respective assupporting environmental factors). The levethe evidence used to assess the various cconclusion are also given (see section 3.2 for 

NI - Ca - O2 - At - DI + Ps - Ck - 

Carlingford Lough 

NP + Mp - Oc 

NPA 

• There is some evidence of nutrient enrich

time scale nutrient concentrations are not not increasing (medium confidence). 

• There is no evidence of accelerated grow

water sampling strategy changed in 1998 

buoy has now been installed. 

• There are no nuisance phytoplankton spe

producing algae incident over the period. growth. Dissolved oxygen is typically >

critical threshold. There are no impacts ocommunities. There is no evidence of un(high confidence). 

The final assessment of Carlingford Lough is (medium confidence) based on evidence that decreasing, some evidence to show that there and strong evidence to show there is no undes
National Report on the Eutrophication Status of UK waters 

April 2008 

Area 

Category I 

Degree of 

nutrient 

enrichment 

Category 

II 

Direct 

effects 

Category III and IV 

Indirect effects/ other possible effects 

Initial classn

Appraisal of all relevant information (coassessment parameters, their respective assupporting environmental factors). The levethe evidence used to assess the various cconclusion are also given (see section 3.2 for 

NI - Ca - O2 + At - DI + Ps ? Ck - 

Foyle Estuary & Lough 

NP + Mp ? Oc 

PA 

• There is some evidence of enrichment of 

N/P ratios are elevated (high confidence)

• There is evidence of accelerated growth i

fluorescence data from an in-situ buoy (m

• Phytoplankton nuisance species levels re

producing algae were recorded but did noevent. Dissolved oxygen is consistently 

both the Lough and the estuary with the oconcentrations in the most upstream of thconfidence). There is no undesirable distzoobenthos communities. Opportunist mlow (medium confidence). 

The final assessment of the Foyle Estuary and Problem Area (medium confidence in in-situ m

evidence of nutrient enrichment, accelerated gof undesirable disturbance in the form of low d
National Report on the Eutrophication Status of UK waters 

April 2008 

Area 

Category I 

Degree of 

nutrient 

enrichment 

Category 

II 

Direct 

effects 

Category III and IV 

Indirect effects/ other possible effects 

Initial classn

Appraisal of all relevant information (coassessment parameters, their respective asupporting environmental factors). The levthe evidence used to assess the various cconclusion are also given (see section 3.2 f

NI - Ca - O2 - At - DI + Ps - Ck - 

Strangford Lough; north 

NP - Mp + Oc 

PPA 

• Nutrient concentrations are elevated abov

DIN/DIP ratios are not. This is classified (medium confidence). 

• Chlorophyll is low and only exceeds the t

occasions. There is no accelerated growth 

• There are no exceptional occurrences in th

Species richness of macroalgae is reduced Lough, with an increased abundance of EDissolved oxygen is predominantly >6 m

an improvement in the community to gooThere is considered to be some evidence ogiven that Enteromorpha spp is taking ov

the Zostera spp. beds (medium confidenc

The north end of Strangford Lough is exhibdisturbance. The final assessment of the StrPotential Problem Area (medium confidencnutrient enrichment (medium confidence), aconfidence) and limited evidence of undesirconfidence) in the form of changing angiospdominance. 
National Report on the Eutrophication Status of UK waters 

April 2008 

Area 

Category I 

Degree of 

nutrient 

enrichment 

Category 

II 

Direct 

effects 

Category III and IV 

Indirect effects/ other possible effects 

Initial classn

Appraisal of all relevant information (coassessment parameters, their respective asupporting environmental factors). The levthe evidence used to assess the various cconclusion are also given (see section 3.2 f

NI Ca - O2 - At - DI - Ps - Ck - 

Strangford Lough; south 

NP - Mp - Oc 

NPA 

• Nutrient concentrations and DIN/DIP r

though there are few recent data (medi

• Chlorophyll is low and rarely exceeds 

confidence). 

• There was only one, short-lived exceed

(2004) in the phytoplankton data. This diversity of macroalgal species and benfluctuates between good and high statubelow the threshold of 6 mg l-1. The zo

undisturbed. There have been no recorbivalve mollusc tissue in the Lough 

The final assessment of Strangford Lough SArea (high confidence), based on good evidenrichment and accelerated growth do not o

to show there is no undesirable disturbance
National Report on the Eutrophication Status of UK waters 

April 2008 

Area 

Category I 

Degree of 

nutrient 

enrichment 

Category 

II 

Direct 

effects 

Category III and IV 

Indirect effects/ other possible effects 

Initial classn

Appraisal of all relevant information (coassessment parameters, their respective asupporting environmental factors). The levthe evidence used to assess the various cconclusion are also given (see section 3.2 f

NI - Ca - O2 - At - DI - Ps - Ck - 

Larne Lough 

NP - Mp ? Oc 

NPA 

• Winter nutrient concentrations within t

background concentrations for the Irish not elevated (high confidence). 

• Chlorophyll is consistently < 6 μg l-1 th

concentrations cannot be considered to there are no data since 2002 (medium c

• There have been no occurrences of alg

Phaeocystis), nuisance algal blooms or mollusc tissue. Dissolved Oxygen con> 6 mg l-1. The benthic invertebrate co

considered consistent with unpolluted There is no undesirable disturbance (hi

The final assessment of Larne Lough is as a confidence) based on good evidence that nuaccelerated growth do not occur, and strong no undesirable disturbance 
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5 Comparisons with European eutrophication related 

policies 

The UK has been active in the development of systems for assessment of sensitive areas 

(eutrophic) under the Urban Waste Water Treatment Directive and polluted waters (eutrophic) 

under the Nitrates Directive, including assessment of waters that may become eutrophic. The 

starting point for all classification schemes is the definition of eutrophication, which has a 

consistent formulation between the EC Directives and the OSPAR strategy. As a result all 

classification methods are based on a similar set of criteria. The assessment methodology, 

however, differs and in the case of the Comprehensive Procedure Assessment may lead to a 

different outcome. This is described in section 6.2.2, below. 

The Comprehensive Procedure Assessment is not carried out in isolation. There has been 

significant development of assessment methodology in the last few years driven by the need 

to assess ecological status under the Water Framework Directive, which covers transitional 

and coastal waters. We have actively sought to ensure that parameter-based assessments for 

both OSPAR and WFD are based on a common scientific understanding. This has led us to 

adopt some of the tools developed under the Water Framework Directive implementation 

strategy (for example for chlorophyll concentration and phytoplankton indicators) for 

application in the Comprehensive Procedure. 

However, the UK has not yet finalised the full classification of waters using the tools 

developed for the Water Framework Directive. This is work in progress and we are, 

therefore, unable to compare and contrast this with the Comprehensive Procedure outcomes. 

It is clear, subject to a few caveats, that the OSPAR Comprehensive Procedure provides a 

reliable and scientifically robust classification of areas of the maritime region as Problem 

Areas and Non-Problem Areas and could usefully contribute to the Initial Assessment that 

will be required for the implementation of the new European Marine Strategy Directive. 
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6 Perspectives 

6.1 Measures taken to address UK Problem Areas and Potential Problem Areas 

6.1.1 Problem Areas and potential Problem Areas designated in 2002 

As mentioned in Section 4.2, a number of small estuaries, harbours and loughs, which had 

already been identified by the UK as either sensitive waters (eutrophic) leading to designation 

as Sensitive Areas (SA) under the UWWT Directive, or as polluted waters leading to the 

designation of Nitrate Vulnerable Zones (NVZ) under the Nitrates Directive were 

automatically designated as OSPAR Problem Areas or Potential Problem Areas in the UK 

report on the first application of the OSPAR Comprehensive Procedure in 2002. These are 

listed in the second column of Table 4 below. 

 

Table 4: UK Problem Areas and Potential Problem Areas reported to OSPAR in first 

application of the Comprehensive Procedure in 2002; sensitive areas (SA) under the 

UWWT Directive and nitrate vulnerable zones (NVZ) under the Nitrates Directive 

Assessment area OSPAR status 

in 2002 

Reason for 

OSPAR status 

Portsmouth Harbour PA SA 

Chichester Harbour PA SA 

Langstone Harbour PA SA 

Pagham Harbour PA SA 

Loughor estuary PPA SA 

Seal Sands (Tees estuary) PA SA 

Lindisfarne NNR area PA NVZ 

Holes Bay PA SA 

Poole Harbour PPA SA & NVZ 

The Fleet PPA NVZ 

Truro, Tresillian and Fal 

estuaries PA SA & NVZ 

Taw estuary PA SA & NVZ 

Tawe PA SA 

Ythan estuary PA SA & NVZ 

Quoile Pondage (in Strangford 

Lough Catchment) PPA SA 

Inner Belfast Lough & tidal 

Lagan impoundment PA SA 
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6.1.2 Measures taken to reduce the inputs of Nutrients from UK Problem 

Areas and Potential problem areas 

Areas designated as Nitrate Vulnerable Zones under the Nitrates Directive

NVZs were originally designated in 1996 and covered approximately 8% of England’s land 

area. Additional NVZs were designated in 2002 and brought the total coverage to 

approximately 55% of England. 

An Action Programme of measures has been implemented by farmers within these NVZs to 

reduce losses of nitrate from agricultural land. The Action Programme promotes best 

practice in the use and storage of fertiliser and manure, and builds on the guidelines set out in 

the ‘Code for Good Agricultural Practice for the Protection of Water’; 

http://www.defra.gov.uk/farm/environment/cogap/. 

There are four key aspects to the Action Programme which require farmers to: 

• Limit inorganic nitrogen fertiliser application to crop requirements, after allowing 

fully for residues in the soil and other sources. 

• Limit organic manure applications to 170 kg ha-1 of total nitrogen each year averaged 

over the area of the farm not in grass and 250 kg ha-1 of total nitrogen each year 

averaged over the area of grass on the farm. 

• On sandy or shallow soils not to apply slurry, poultry manures or liquid digested 

sludge between 1 September and 1 November (grassland or autumn sown crop) or 1 

August and 1 November (fields not in grass without autumn sown crop). The storage 

capacity available for those animal manures which cannot be applied during the 

autumn closed period must be sufficient to cover these periods unless other 

environmentally acceptable means of disposal are available. 

• Keep adequate farm records, including cropping, livestock numbers and the use of 

organic manures and nitrogen fertilisers. 

Four NVZs were designated in Scotland in 2002, comprising 14% of the land area. They 

incorporate areas earlier designated, one of which was the Ythan catchment. 

In 1999 and 2003 Northern Ireland designated seven small Nitrate Vulnerable Zones (NVZs) 

due to elevated nitrate levels in groundwaters. In October 2004 a total territory approach to 
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the implementation of the Directive was adopted in Northern Ireland due to eutrophication of 

surface waters and the ‘Nitrates Action Programme Regulations (Northern Ireland) 2006’ (the 

NAP Regulations) came into operation on 1 January 2007. The introduction of these 

regulations meets Northern Ireland’s legal and environmental obligations and the ‘Phosphorus 

(Use in Agriculture) Regulations (Northern Ireland) 2006’, which also became operational on 

1 January 2007, support these obligations. These regulations bring into operation measures to 

improve the use of nutrients on farms and as a result improve water quality throughout 

Northern Ireland. 

Some of the key measures in the NAP Regulations include: 

• A closed period for the spreading of organic (15 Oct to 31 Jan) and inorganic 

fertilisers (15 Sept to 31 Jan); 

• A minimum livestock manure storage requirement (26 weeks for pig/poultry and 22 

weeks for other livestock); 

• A limit on the amount of nitrogen that can be applied to land from livestock 

manures (170kg N ha-1 year-1); and 

• The inclusion of nitrogen efficiency measures. 

In addition to the measures described in action plans, Member States are required to carry out 

effectiveness monitoring of the action plans. In Northern Ireland, the effectiveness of the 

programmes is measured by: 

• Monitoring surface (~600) and groundwater (~90) stations on a monthly basis for 

compliance with the 50mg l-1

• Trophic status monitoring of rivers, lakes and transitional/coastal waters, measuring 

both chemical and biological determinands on a rolling programme. 

• Detailed nutrient budgeting of catchments 

• Intensive survey at targeted mini-catchments, with known eutrophication problems 

• Soil mineral N analysis 

The studies outlined above are carried out in conjunction with other government laboratories. 
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Waters Designated as Sensitive under the Urban Wastewater Treatment Directive

The Urban Waste Water Treatment Directive (UWWTD) sets requirements for the collection, 

treatment and discharge of urban wastewater and also establishes timetables for the 

achievement of these standards according to the sensitivity of the waters. 

The Directive requires that sewage being discharged to SAs should be subjected to tertiary 

treatment to standards given in the Directive, within seven years of designation. 

The SAs mentioned above were designated in 2002 or earlier. Appraisals of wastewater 

treatment plants discharging into the SAs and the installation of remedial measures where 

appropriate are either completed or underway, but a full report on how the various measures 

have been implemented will not be available until after the seven year deadline has been 

reached in 2009. 

Improvements in the ecology of the waters in Belfast Lough have already been noticed since 

the installation of nitrogen removal at four wastewater treatment plants discharging into the 

Lough. 

More details on how the UK is working to achieve reductions in nitrogen inputs to the marine 

environment can be found in the implementation reports for OSPAR Recommendations 88/2, 

89/4 and 92/7 which can be found on the OSPAR website. 

6.2 Outlook 

6.2.1 Expected trends 

Using data collected for the OSPAR Riverine Inputs and Direct Discharges survey we have 

completed statistical trend analysis for four areas. There are no statistically significant trends 

in the combined riverine and direct input of DIN from four major UK catchments: the Bristol 

Channel, Liverpool Bay, Humber/Wash and the Thames. The lack of trend may be explained 

where measures have been taken, under EC Directives, by the long lag time in environmental 

systems and by the possible confounding effects of environmental change. Experts have 

indicated that, due to the large existing reservoirs of nitrogen in soils and sediments, it could 

be decades before measures such as improved agricultural practice with respect to fertilizer 

and manure use will begin to show measurable improvements in environmental quality. There 

are circumstances where, in relation to management of point sources, environmental benefits 
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can be realised quickly; for example, there is local evidence that inputs of phosphorus are 

lower in recent years compared to previous times, resulting from the introduction of improved 

urban waste water treatment. 

There is a risk that climatic change may affect the eutrophication status of areas of UK waters 

through either change in physical or biological process driven by warming, or by changing the 

nutrient input through varying precipitation. Examples of possible change are described 

below. 

The depth of mixing at the continental shelf boundary determines the background 

concentration of nutrients experienced across the shelf seas around the UK. This is known to 

respond to storminess which is considered to be increasing due to climatic change and could 

result in a change in the background nitrogen concentration. Such change is likely to be in a 

narrow range with limited implication for our current assessments of coastal water 

eutrophication status. 

Taking account of realistic climate change scenarios (UKCIP02 Briefing Report, 2002) we 

may expect the delivery of nutrients to change in estuarine and coastal areas, with higher 

loadings in the winter and a reduction during the summer. The direct impact of this change 

over many decades is difficult to predict and may form the subject of further investigation. 

Changes in temperature affect phytoplankton physiology and may result in shifts in species 

composition of phytoplankton (McQuatters-Gollop, 2007) as well as affecting the duration 

and strength of thermal stratification of the deeper (> 40 m) shelf seas. There is therefore 

concern that the growth response of organisms to nutrient enrichment may change and that, 

for example, deoxygenation of bottom waters in stratified regions may increase. It may be 

that parts of the seas become more ‘susceptible’ to the effects of nutrient enrichment, but it is 

also clear that distinguishing between cause and effect will become more difficult. We can 

predict such changes using ecosystem models but we are currently building confidence that 

these predictions form a good basis for management action. 

Subject to the qualifications given in the above paragraphs, the expected status of UK 

assessment areas is summarised in Table 5 
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Table 5: Expected Eutrophication Status of UK waters examined under the OSPAR 

 Comprehensive Procedure 

Country Assessment area OSPAR 2002 

assessment 

OSPAR 2008 

assessment 

Expected 

status 

Northern North Sea NPA NPA

Southern North Sea NPA NPA 

Eastern English Coast NPA NPA 

East Anglia NPA NPA 

East English Channel NPA NPA 

Solent NPA NPA 

Bristol Channel NPA NPA 

Liverpool Bay NPA NPA 

England 

and Wales 

Northeast Irish Sea NPA NPA 

Clyde estuary NPA NPA 

Firth of Clyde NPA NPA 

Forth estuary NPA NPA 

Tay estuary NPA NPA 

Solway NPA NPA 

Scotland 

Eden NPA NPA 

Carlingford Lough NPA NPA 

Larne Lough NPA NPA 

Strangford Lough South NPA NPA 

Northern 

Ireland 

Outer Belfast Lough NPA NPA 

Expected to 

remain as 

non-problem 

areas, subject 

to significant 

climatic 

changes 

Lower Fal estuary [PA]3 

Portsmouth & Chichester Harbours PA PA 

Langstone Harbour PA PA 

Pagham Harbour PA PA 

Medina estuary PA 

Newtown Harbour PA 

Eastern Yar [PA] 1

Loughor estuary PPA PA 

Hamble estuary PA 

Seal Sands (Tees estuary) PA PA 

Lindisfarne NNR area PA PA

Holes Bay PA PA 

Poole Harbour PPA PPA 

The Fleet PPA PPA 

Truro, Tresillian and Fal estuaries PA PA 

Taw estuary PA PA 

Tawe PA PA 

South Esk estuary (Montrose basin) PPA4

Ythan estuary PA PA 

Inner Belfast Lough & tidal Lagan impoundment PA PA 

Strangford Lough North PPA 

Estuaries 

And 

Harbours 

In England 

Wales 

Scotland 

And 

Northern 

Ireland 

designated 

as SAs or 

NVZs, or 

“whole 

territory” 

Under the 

UWWT 

and/or 

Nitrates 

Directive. 

Foyle estuary and Lough PPA 

Measures being 

applied under 

UWWT and/or 

Nitrate 

Directives, in 

conjunction 

where 

appropriate with 

any future 

measures under 

the WFD, should 

lead to progress 

towards NPA 

status. However 

the timeframe is 

uncertain due to 

the complexities 

of the science 

including the 

effect of nutrient 

reserves in soils 

and sediments

. 

(see para 

6.2.1) 

 

3 Status of areas in square brackets is provisional and dependent on formal designation under the Nitrates 

Directives. UK will inform OSPAR when the position is clear. 4

 the South Esk estuary (Montrose Basin) is not designated as an NVZ, but most of the catchment in which it is 

situated has been designated as an NVZ. Therefore, this area should benefit from the associated nitrogen 

reductions. 
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6.2.2 Improvement of assessments 

There are three issues that come out of the peer review of our application of the 

Comprehensive Procedure and that the UK believes would assist OSPAR to develop/refine 

the procedure for future applications. 

Algal toxicity and eutrophication. The first of these is the use of Category IV concerning 

Other Possible Effects. Although we have included information about the incidence of 

DSP/PSP toxicity in bivalve mollusc tissue, and added to this with readily available 

information about the presence of toxin producing algae, we do not think this information 

adds anything to the overall classification of eutrophication status and in some cases might 

provide a wrong classification. There is continuing scientific debate about the link between 

nutrient enrichment and both the presence of TPA and toxicity in bivalve mollusc tissue. 

There is evidence that TPA occur in regions where there is no anthropogenic nutrient 

enrichment, e.g. along the Atlantic coasts of the UK. Until such time as there is clear 

scientific justification we propose not to use TPA and the presence of toxicity in shellfish as 

assessment criteria. The UK is commissioning a research project to address this question 

together with other countries which will report in early 2009. 

Adequacy of macrophyte tools. Although we have developed assessment methods for 

macrophytes, including macroalgae, in shallow coastal and estuarine waters there is scope for 

improving our quantitative assessment tools. There has been considerable attention given to 

this area in the work streams supporting the implementation of the Water Framework 

Directive (Scanlan et al., 2006) and it will be several years before the adequacy of the new 

tools is confirmed. OSPAR needs to ensure that it contributes to, and benefits from, 

experience gained in applying this ecological assessment tool. 

Lack of clarity in the application of Category II. The most serious of the problems 

identified, concerns the application of the Category II Harmonised Assessment Criteria where 

there is a mix of criteria reflecting different aspects of the overall definition of eutrophication. 

It is clear that the indicators in Category I relate unambiguously to nutrient enrichment. It is 

also clear that the criteria in Category III relate unambiguously to undesirable disturbance to 

the balance of organisms or to the quality of the water. In contrast Category II contains 

elements that relate to accelerated growth (e.g. chlorophyll and macrophyte biomass) and to 

undesirable disturbance to the balance of organisms or to the quality of the water (e.g. 

phytoplankton indicator species and ‘shifts’ in the nature of the macroalgae/macrophytes). 
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Our experience shows that this can lead to a situation where misclassification is possible. The 

most concrete example is where in the Initial Classification there is a ‘+’ for Category I, a ‘+’ 

for Category II (relating only to chlorophyll) and a ‘–’ for Category III/IV. The combined 

scores give a Problem Area Classification. This means that the area is nutrient enriched and 

that there is accelerated growth but the final test for eutrophication – undesirable disturbance 

to the balance of organisms or to the quality of the water – has not been met. According to 

the definition of eutrophication this type of area is a Non-Problem Area (or may be a Potential 

Problem Area if there are increasing trends related to nutrients and chlorophyll). This 

anomaly requires a change to the assessment scheme by separating out those criteria relating 

to undesirable disturbance from Category II. 
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7 Conclusions on the Eutrophication Status of UK Seas 

The results of the latest, more robust, application of the OSPAR Comprehensive Procedure 

which assesses the eutrophication status of UK seas, generally confirms those of the first 

application in 2002. The evidence revealed by the monitoring programmes clearly shows, 

with a good degree of confidence, that the coastal and marine waters around the UK are Non 

Problem Areas with respect to eutrophication and show no signs of undesirable disturbance. 

However, the evidence confirms that there are a number of small estuaries, loughs and 

harbours which are Problem Areas with respect to eutrophication, or are at risk due to factors 

such as restricted circulation. 

The overall classification results for the UK areas subject to the Comprehensive Procedure are 

listed in Table 6 There are 19 areas classified as Non Problem Areas, 17 areas classified as 

Problem Areas and 5 areas that are Potential Problem Areas, with respect to eutrophication. 

The status of these areas has been identified using the Comprehensive Procedure 

methodology, or the Urban Waste Water Treatment Directive or the Nitrates Directive, where 

theses directives were used in the original assessment of some areas (Table 6). 

These areas fall into two categories. 

1. Coastal and Offshore marine waters (salinity >30) – which were identified as Non 

Problem Areas in 2002 and remain Non Problem Areas. We are more confident in 

the results of the current assessment, especially in the coastal areas identified in 2002 

as areas of particular ongoing interest, due to enhanced monitoring and research 

programmes that were designed to detect any adverse anthropogenic related changes 

that could threaten the NPA status. These areas are East England, East Anglia, 

Liverpool Bay and the Solent and the Clyde. 

2. Restricted regions including estuaries, loughs and harbours – some of which were 

identified as Problem Areas or Potential Problem Areas in 2002 (see table 4 ). 

Through the ongoing assessment programme related to the implementation of EC 

Nitrates and Urban Wastewater Treatment Directives a further 5 Problem Areas and 3 

Potential Problem Areas have been identified5

. These are all small water bodies. 

The possible impacts of climatic change on the assessment have been considered and while 

there may be a tendency, in some areas, to increase the risk of nutrient enrichment related 

 

5

 The status for the Lower Fal Estary and the Eastern Yar is provisional, and is dependent on formal designation 

under the Nitrates Directive later in 2008. UK will inform OSPAR when the position is clear. 
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effects in the seas, further work is required to help develop confidence in such prediction. 

Currently predicted change would only become significant several decades into the future. 

The second application of the Comprehensive Procedure has helped develop our 

understanding of the eutrophication status of UK waters, and the assessment methods for each 

of the Harmonised Assessment Criteria from developments in the underpinning science and 

parallel developments for the purposes of the Water Framework Directive. One of the 

outcomes is a clear conclusion that several components of the overall assessment process 

need to be refined, in order to come to a clearer and more robust conclusion reflecting the 

definition of eutrophication. 

Figure 5 is a map of these final classifications and Figure 6a and Figure 6b show the 

assessment areas for Northern Ireland and Scotland on a smaller scale. Figure 6c presents a 

small-scale map of the south coast of England in order that the classifications of estuarine 

areas in this region are visible. 
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Table 6: Final classification of UK areas 

Country Assessment area OSPAR 2002 OSPAR 2008 

Northern North Sea NPA NPA 

Southern North Sea NPA NPA 

Eastern English Coast NPA NPA 

East Anglia NPA NPA 

East English Channel NPA NPA 

Solent NPA NPA 

Bristol Channel NPA NPA 

Liverpool Bay NPA NPA 

England and Wales – 

Coastal and offshore areas 

Northeast Irish Sea NPA NPA 

Lower Fal estuary [PA]6

Portsmouth & Chichester Harbours PA PA

Langstone Harbour PA PA 

Pagham Harbour PA PA 

Medina estuary PA 

Newtown Harbour PA 

Eastern Yar [PA] 7 

Loughor estuary PPA PA 

Hamble estuary PA 

Seal Sands (Tees estuary) PA PA 

Lindisfarne NNR area PA PA 

Holes Bay PA PA 

Poole Harbour PPA PPA 

The Fleet PPA PPA 

Truro, Tresillian and Fal estuaries PA PA 

Taw estuary PA PA 

England and Wales – estuaries 

Tawe PA PA 

Clyde estuary NPA NPA 

Firth of Clyde NPA NPA 

Forth estuary NPA NPA 

Tay estuary NPA NPA 

Solway NPA NPA 

South Esk estuary (Montrose basin) PPA 

Ythan estuary PA PA 

Scotland 

Eden NPA NPA 

Inner Belfast Lough & tidal Lagan impoundment PA PA 

Carlingford Lough NPA NPA 

Larne Lough NPA NPA 

Strangford Lough North PPA 

Strangford Lough South NPA NPA 

Outer Belfast Lough NPA NPA 

Northern Ireland 

Foyle estuary and Lough PPA 

 

6

 Status dependent on formal designation under the nitrates Directive 

7

 Status dependent on formal designation under the nitrates Directive 
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Figure 5: Final classification for UK assessment areas. 
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Figure 6: Map extracts of assessment areas in (a) Scotland, (b) Northern Ireland, and (c) 

English south coast. 

c 

a 

b 
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8 References 

CSTT (1994). Comprehensive studies for the purposes of Article 6 of DIR 91/271 EEC, the 

Urban Waste Water Treatment Directive. Published for the Comprehensive Studies Task 

Team of Group Coordinating Sea Disposal Monitoring by the Forth River Purification Board, 

Edinburgh. 

CSTT (1997). Comprehensive studies for the purposes of Article 6 & 8.5 of DIR 91/271 EEC, 

the Urban Waste Water Treatment Directive, second edition. Published for the 

Comprehensive Studies Task Team of Group Coordinating Sea Disposal Monitoring by the 

Department of the Environment for Northern Ireland, the Environment Agency, the Scottish 

Environmental Protection Agency and the Water Services Association. 

Marine Environment Monitoring Group, (Cefas) (2004). UK National Marine Monitoring 

Programme – second report (1999 – 2001). Cefas 

McQuatters-Gollop A., Raitsos, D.E., Edwards, M., Pradhan, Y., Mee, L., Lavender, S., 

Attrill, M. 2007. A long-term chlorophyll data set reveals regime shift in North Sea 

phytoplankton biomass unconnected to nutrient trends. Limnology and Oceanography, 

52(2):635–648. 

Scanlan, C.M., Foden, J., Best, M.A. & Wells, E. (2007). The monitoring of opportunistic 

macroalgal blooms for the Water Framework Directive. Marine Pollution Bulletin, 55: 162 – 

171. 

UKCIP02 Briefing Report (2002). Climate Change Scenarios for the United Kingdom. The 

UKCIP02 Briefing Report, April 2002. 
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9 Annexes 

9.1 Screening Review 

After considering possible changes to the drivers for nitrogen, including any measures taken 

for national or European purposes, we screened the marine waters around the UK using a 

simple approach based on winter nutrient concentrations. Winter nitrogen data (dissolved 

inorganic nitrogen – DIN) from all available surveys were used and where available 

supplemented by information on TOxN derived from SmartBuoys. SmartBuoys measure total 

oxidised nitrogen (TOxN), but not ammonium so DIN data are not calculable. However, 

examination of spatial data (sampled from ship-borne surveys) in an area 150 – 300 km2

around each SmartBuoy found that ammonium constituted <6% of DIN in >90% of samples; 

so SmartBuoy TOxN data slightly underestimates spatial DIN data and may be used for 

screening purposes. 

Table 7: Summary results of the 2008 screening procedure for England and Wales. 

Data were separated into spatial and temporal. 

Mean winter DIN (spatial) & TOxN 

(SmartBuoy) (μM) for whole assessment 

period 

Spatial (NMMP, EA) Assessment area

Estuarine Coastal Offshore 

SmartBuoy 

(Cefas) 

Full 

assessment?

Liverpool Bay 55.47 30.06 - 18.47 Yes 

Northeast Irish Sea - 19.64 - - Yes 

Cardigan Bay - 11.42 - - No 

Bristol Channel 56.27 25.97 - - Yes 

North Cornwall Coast - - 8.72 - No 

SW England Coast - - 8.53 - No 

East English Channel Coast 160.02 18.63 10.32 - Yes 

Solent 142.20 30.73 17.24 - Yes 

East Anglian Coast 43.95 31.13 19.35 23.99 Yes 

Eastern English Coast 93.03 58.60 9.06 - Yes 

NE England Coast 57.94 15.00 8.65 - No 

Northern North Sea - - 6.01 - Yes 

Southern North Sea - 25.42 10.16 7.02 Yes 

Data were averaged over the 6-year assessment period. Winter nutrient concentrations 

exceeding 15μM in coastal and offshore waters were put forward for assessment under the 

OSPAR comprehensive procedure. The exception was the Northern North Sea area, which 

did not exceed the DIN threshold but was examined due to interest in relation to the 

contiguous areas to the east. It has been put forward for a full assessment due to trans-
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boundary transport debate. The outcomes of the screening procedure for defining the areas 

considered to be non-problem are set out in Table 7. 
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9.2 Thresholds used in the OSPAR comprehensive procedure 

9.2.1.1 Phytoplankton 

Table 8 is a summary of individual phytoplankton indices’ thresholds and the summary 

equation relating to the occurrences of elevated phytoplankton taxa counts within a whole 

population. The overall index is composed of counts of the four attributes within the tool. 

Samples are taken in the growing season between April and September. The 

GOOD/MODERATE boundary equates to the problem/non problem threshold for OSPAR 

CP. Phytoplankton data were extracted from the UK phytoplankton database. These data 

have been compiled for WFD purposes, and are geographically linked to WFD transitional 

(estuarine; salinity <30) and coastal (salinity 30-34) water bodies. 

Table 8: Summary of phytoplankton indices (IE) relating to the occurrences of elevated 

taxa counts within a whole population 

Normative 

definition Index 

Equation – 

{SUM [T] + [P] + [S]+[CHL]/4} *100 Phytoplankton 

assessment 

<25% 

Threshold not 

Phytoplankton exceeded 

abundance IE 

IE: sum of the occurrence of any species 

(> 106

), 

plus Phaeocystis (>106

), 

plus total cell counts (>107

) 

and counts of chlorophyll > 10ug/l over a 

five year period 

>25%

Threshold 

exceeded 

9.2.1.2 Macrophytes (macroalgae) 

The proposed thresholds for assessment of areas with macroalgal bloom events are set out in 

Table 9. They have been adapted from Water Framework Directive macroalgal bloom 

metrics (Scanlan et al., 2007). 

Table 9: Thresholds for assessment of macroalgae blooms under the OSPAR CP 

Macroalgal biomass Macroalgal cover 

Macroalgae 

assessment 

<500g/sqm <15% Threshold not exceeded 

>500g/sqm >15% Threshold exceeded 
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9.2.1.3 Dissolved oxygen 

Table 10 sets out the standards for dissolved oxygen (DO) levels during the growing season, 

as proposed for WFD assessment and these have been simplified for OSPAR. Regions are 

deemed to have exceeded the OSPAR threshold where DO levels is below 4 mg l-1 on more 

than 5% of sampling occasions during the growing season. 

Table 10: Proposed dissolved oxygen standards for naturally ventilated layers (or 

rapidly exchanged stratified waters) of transitional and coastal waters. 

Marine 5%ile Objectives DO 

assessment 

≥5.7 mg l-1 All life-stages of salmonids and transitional fish 

≥4.0 <5.7 mg l-1 Presence of salmonids and transitional fish Threshold not 

exceeded 

≥2.4 <4.0 mg l-1 Most life-stages of non-salmonid adults 

≥1.6 <2.4 mg l-1 Presence of non-salmonids, poor survival of salmonids 

<1.6 mg l-1 No salmonids present marginal survival of resident 

species 

Threshold 

exceeded 

9.2.1.4 Zoobenthos/benthic invertebrates and reported fish kills 

Sea Fisheries Commissions were contacted for data on incidents of fish kills. 

Under the Water Framework Directive benthic metrics, methods and thresholds are being 

established but this is work in progress and results are not yet available. Monitoring of the 

benthos has been regularly undertaken by Cefas, though it has not been directly targeted at 

assessment of eutrophication. Where relevant, results from the UK National Marine 

Monitoring Programme (NMMP) second report (MEMG Cefas, 2004) and Cefas’ Defrafunded research and development study of “The Benthic Ecology of the Western North Sea”, 

have been used in area reports. 

9.2.1.5 Toxin levels in bivalve mollusc tissue 

For the assessment of bivalve mollusc tissue poisoning events, the procedure set out in the 

Water Framework Directive characterisation report was used. Table 11 sets out the thresholds 

for OSPAR exceedance, based on the percentage of bivalve mollusc tissue samples failing to 

meet FSA standards. As further supporting evidence, TPA concentrations in water samples 

were also assessed against the same threshold of 10% of samples exceeding the FSA 

permitted levels. 
National Report on the Eutrophication Status of UK waters 

April 2008 

67

Table 11: Assessment criteria for Category IV – occurrence of toxicity in bivalve 

mollusc tissue and presence of toxin producing algae. 

Toxin 

Maximum 

permitted 

levels 

TPA species Shellfish 

poisoning 

Action Level 

(cells l-1) 

PSP 80 μg per 100 g 

flesh 

Alexandrium 

tamarense 

PSP Present 

DSP Presence in 

flesh Dinophysis spp. DSP 100 

Prorocentrum lima DSP 100 ASP 20 μg per g 

flesh Pseudonitzschia spp. ASP 150,000 

Proportion of failed samples (whichever was most for 

ASP/PSP/DSP) 

Toxicity in bivalve mollusc 

tissue and TPA assessments 

<10 % Threshold not exceeded 

>10 % Threshold exceeded