EA Reports post 1997

The following reports are a selection of those available from the EA's R&D Dissemination Centre. They are presented to illustrate the type of information available. For the latest information visit http://www.eareports.com and use the 'search' or 'browse' facilities.

Publishing reference: Environment Agency R&D Technical Report P203

Report Title: Determining the Causes of 'Apparent Eutrophication' Effects

Summary:
When the symptoms of eutrophication are observed in a river the common assumption is that excess nutrients from sewage treatment works upstream are the cause and that the appropriate response is to remove phosphorus from the effluent. However there are many other causes which can result in the changes to aquatic systems which resemble the effects of eutrophication. The possibility that one of these effects is a cause needs to be considered, and discounted, at an early stage, before proceeding to consider phosphorus control from point or diffuse sources. Since, at this stage, the effects have not been confirmed as eutrophication ie excessive growth of aquatic plants due to excess nutrients introduced from anthropogenic sources, the stage has been termed 'Apparent Eutrophication'.

The report documents the factors controlling plant growth and, on the basis of these factors, a list of potential causes of eutrophic effects is presented. A simple checklist scheme is proposed to assess the likelihood that any of these alternative causes may be driving the observed effects. This ensures that a wide range of possible causes of eutrophication are considered at an early stage in the consideration of remedial management.
 

Publication Year:	1998
Authors:	J Hilton and G P Irons (Corporate authors: Institute of Freshwater Ecology)
Funder/Sponsor:	Environment Agency

Publishing reference: Environment Agency Avon Eutrophication Study final report
Report Title: Eutrophication in controlled waters in the Warwickshire Avon catchment

Summary:
The River Avon catchment in Warwickshire, UK has shown signs of accelerated algal growth in recent years by the presence of attached and planktonic algae, and nuisance blue-green algal blooms. Consequently, the River Avon was designated as Sensitive Areas (Eutrophic) under the Urban Waste Water Treatment Directive (UWWTD) in 1994. This research aimed to evaluate the impact of qualifying sewage treatment works (STW) discharges and 13 minor STW discharges on nutrient concentrations and loads in the River Avon, and estimate the potential reduction in nutrient concentrations and loads based on nutrient removal estimates at the five qualifying STWs.

The project summarises the findings from a water quality and flow dataset collected in the Warwickshire Avon catchment during the period December 1994 to September 1996. Analysis of the dataset showed that although implementation of the UWWTD at the five major STWs will reduce phosphorus (P) loads at the catchment outlet by 50%, concentrations will still exceed the DoE threshold for eutrophication. Implementation of the UWWTD threshold concentrations at all STWs would result in a further P load reduction of ca. 15%. It is apparent that P removal in isolation will not produce P concentrations below the limits cited in the literature as being likely to limit eutrophication.

Publishing reference: R&D Publication No.13 (HO-06/98-5K-B-BCJL)
Project Title: Diffuse pollution from agriculture - a field guide

Summary
The findings of R&D on best management practices to control diffuse pollution have been collated into a field guide for use by Agency staff and other environmentalists.

The booklet contains examples of situations where diffuse pollution of water is likely to arise and suggests what can be done to reduce it. The aim of the booklet is to raise awareness about the general problems and solutions.

Subjects covered in the booklet include:

• What is diffuse pollution?
• The role of the Environment Agency
• Recognising signs of diffuse pollution
• Impacts of diffuse pollution
• Encouraging farmers to act
• Integrated crop management
• Integrated Farming systems
• Pesticide minimisation
• Nutrient management
• Cultivation techniques
• Winter cover
• Use of grass
• Livestock management
• Tracks and access routes
• Hedge planting and management
• Wetland restoration and creation

Publishing reference: R&D Technical Report P20

Publication R&D Technical Report P20: Agricultural Waste Minimisation

Summary
Although improvements have been made, diffuse and point-source pollution from agriculture still remain a significant problem. This project aimed to demonstrate the benefits to farmers of farm waste minimisation in order to encourage them to undertake the necessary investment and /or adopt improved management practices to reduce the risks of pollution.

A small number of farms were selected to represent a range of farming operations. Using a questionnaire and a series of guidance notes on how to assess the benefits of waste minimisation, each farmer was encouraged to develop an action plan to tackle priority problems. Considerable good practice was identified, with some developments potentially of national importance.

Based on the results, it is concluded that while waste minimisation is already part of farming in England and Wales, farmers are not generally aware of the scale of benefits they could gain from reducing, reusing or recycling their wastes. There is considerable potential to extend the benefits of waste minimisation in the industry. Demonstration of good practice is considered a valuable way to develop the culture of waste minimisation, which should be considered on existing demonstration farms.

The report includes a suggested strategy for the Environment Agency, which includes setting targets, improving communication, providing support for farmers, improving the auditing process by consulting widely with industry organisations, and promoting or undertaking related R&D.

Publishing reference: R&D Technical Report P72

Publication: R&D Technical Report P72 - Benthic Algal Mats in River Systems

Summary
Floating algal mats are frequently reported in UK rivers between March and November. Many of these reports come from the public, who confuse them with sewage. Although the dominant taxa in most mats are diatoms, in a few it is blue-green algae (principally Oscillatoria / Phormidium-type). There is concern about the potential for these blue-green algal mats to cause illness to river users.

This project was commissioned to determine whether benthic algal mats are likely to cause concern for the Environment Agency. The purpose of this research was to investigate occurrences of algal mats between Agency Regions and examine the way in which risks were assessed.

This study confirmed 16 reports of blue-green algal mats in 1996, from five Agency Regions. All Regions reported the occurrence of mats, but many were assumed to be dominated by diatoms. Animal illness and rashes on bathers (and Agency staff) were reported in two Regions.

A uniform approach to managing these incidents is recommended in order to bring the treatment of benthic algal mats in rivers into line with national policy on blue-green algae. A standardised procedure is described. Adoption of such an approach, in conjunction with consistent record keeping and auditing of key stages, will permit a clearer picture of the distribution of these incidents to emerge.

Publishing reference: R&D Technical Report P47

Publication: R&D Technical Report P47: The evaluation of EnviroGard microcystin plate and tube kits

Summary
Blooms and scums of cyanobacteria (blue-green algae) occur annually in many freshwaters throughout the United Kingdom. All of the common bloom and scum-forming types of cyanobacteria have the potential to produce toxins which present a hazard to human and animal health. In order to monitor and determine the toxicity of a sample, sensitive and specific methods for detection, identification and quantification of these toxins are required.

In 1995, the Environment Agency undertook to evaluate a new microcystin toxin immunoassay technique for potential use by Agency staff in the field evaluation of blue green algal blooms. In addition to this, the Agency also collaborated with an initiative by the Standing Committee of Analysts (SCA) to develop further the 1994 method, "Determination of microcystin-LR in drinking waters by HPLC "to include other microcystin toxins and environmental water samples.

The immunoassay test kits evaluated are commercially available in the United Kingdom, and come in two forms, a plate kit and a tube kit. The performance of each of these was investigated to determine its accuracy for detection of microcystins in water. Further studies were undertaken to determine the potential for use in monitoring for other cyanobacterial toxins and use with environment samples. The kits were further assessed against ease of use. Comparisons were made against proven methods, including HPLC-DAD, bioassay and PPI, using standard laboratory cultures and purified samples.

Results showed that the plate test kit provided more accurate results in comparison with the tube kit. In addition, the immunoassay system was also proven to work well with another toxin, nodularin.

The Agency's collaboration with the SCA, Drinking Water Inspectorate and other independent laboratories, has led to the development of a revised multi-microcystin analytical method suitable for use by the Water Industry both in drinking water samples and environmental samples.

Publishing reference: R&D Technical Report P78

Publication: R&D Technical Report P78: Sustainable systems of outdoor pig production - Runoff from outdoor pig production

Summary
Outdoor pig production has expanded rapidly in recent years and the trend may continue with a ban on sow stalls (a method of indoor production) set to come into force in 1999. Little was known of the incidence and nature of pollution from land stocked with outdoor pigs of the potential polluting effects of run-off from such land. The project aimed to assess the risk of pollution to surface waters and provide some recommendation designed to reduce that risk.

A survey of outdoor pig units was undertaken with the assistance of companies servicing the pig industry. The location of each sample herd was related to soil type, proximity to watercourses and other water features, land drainage, slope, erosion risk and rainfall and the following characteristics identified: stocking rate and type, tenure, previous crop, and vegetation at the time of survey. Risk scores were estimated for six factors and these were accumulated to provide an overall assessment of risk from the sample sites.

The main risk factors identified for any outdoor pig site are its proximity to surface waters and/or the presence of an underlying aquifer. Pollution risk can be reduced by identifying and controlling vectors that might be used by water moving overland and by sensitive location and layout of units to reduce the potential for generation of surface run-off.

The report makes recommendation for specific measures that might be taken to reduce risk. The design of outdoor pig units should take account not only of ease of management , but also the area of land within and uphill of a unit likely to lead to the generation of surface run-off. It suggests that vehicle access should be controlled and that the inclusion of specially designed buffer features in the layout of units may be of benefit in reducing the potential for surface run-off.

Publishing reference: P2-553 (P26)

Publication: Farm effluent treatment: an innovative approach

Summary
Dairy farms produce large volumes of effluent in the form of faeces and urine ('slurry'), associated wash waters and contaminated drainage. The main objective of the project was to design and evaluate a treatment system for such materials, to be installed on a working dairy farm. The intention was for the system to separate the solid and liquid fractions of the materials in such a way that the solids could be stored for use as fertiliser, without threat to the local environment, and the liquid could be disposed of to land, soakaway, or direct to a watercourse subject to consent conditions imposed by the Agency.

This collaborative project, was carried out by Wisdom Agricultural Ltd at a Herefordshire dairy farm which was milking approximately 400 cows per day.

After some considerable difficulty, a basic design evolved which produced the desired standard of solids separation and liquid effluent quality, using chemical flocculation and dewatering of the resultant sludge using a belt press. A biological filtration tower was also added to improve the standard of the liquid effluent produced. The final results showed that the evolved process could significantly reduce the pollution effects of farm effluent at a cost that could be justifiable at many large dairy farms.

Publishing reference: R&D Technical Report E3:

Publication R&D Technical Report E3: Diatoms as Tools for Water Quality Managers

Summary

A requirement of the Urban Waste Water Treatment Directive (UWWTD) is to identify 'eutrophic sensitive areas'. There have been difficulties using macrophytes to identify ESAs in some parts of the country, due to interpretive and hydrological problems. Moreover, macrophyte communities are relatively slow to respond to environmental change.

Diatoms (a group of microscopic algae) have been suggested as having potential for monitoring trophic status of rivers. The objective of this R&D project was to further develop a simple diatom index of eutrophication and test it in contrasting areas, and evaluate results alongside other data collected for designation reviews.

Four Areas were selected to undertake the evaluation. Before starting the evaluation, training material and a users manual (Technical Report E2) were produced, so that staff could learn enough about diatom identification and related skills to use the Trophic Diatom Index (TDI).

The evaluation showed that the technique can be used to monitor nutrients in rivers, and can be used for preparing cases for the next round of designations for the UWWTD. The evaluation of the technique by staff has also indicated that diatoms may provide information on other water quality problems where routine invertebrate monitoring is not effective.

Publishing reference: R&D Technical Report E55

Publication: Nutrient and Phytoplankton Distributions in the North-East Irish Sea during1997

Summary

This research investigates the trophic state of waters in the north-eastern Irish Sea between 1995-1998. Primary objectives were to monitor the distribution and concentrations of nutrient and phytoplankton abundances of these waters with regard to the European Union's 'Urban Waste Water Treatment Directive'. The high residence times of waters in the eastern Irish Sea coupled with high anthropogenic inputs of nutrients raise concern as to the ability of these nutrients to disperse and there is further concern with regard to steadily increasing nutrient concentrations over the past forty years or so. Specific objectives of the research have been to identify areas potentially at risk from the adverse effects of excessive nutrient discharges from sewage and industrial outfalls.

At present the concentrations of both phosphate and nitrogenous compounds around Whitehaven (Albright & Wilson discharge) and Sellafield (BNFL discharge) far exceed the recommendations of the Comprehensive Studies Task Team (CSTT) for High Natural Dispersal Areas (HNDA's). Concentrations of surface chlorophyll, however, did not exceed the 10mg/litre threshold for summer concentrations as outlined by the CSTT during 1997. A comparison of winter nutrient salts and spring phytoplankton community structure suggests that the winter concentrations of nitrogenous compounds may best explain the phytoplankton community structure, however, no causative link can be assumed.

Nutrient concentrations in Liverpool Bay exceeded the criteria outlined by the CSTT during the winter sampling period. Concentrations of surface chlorophyll exceeded the CSTT recommendations during April but had declined during the summer months to levels acceptable under these guidelines.

The collaborative research programme is continuing, with the work focusing on the variation of nutrient salt concentrations and phytoplankton community structure throughout the water column.

Publishing reference: R&D Technical Report P14 Publication: R&D Technical Report P14 -Biogeochemical Controls on Phosphorus Cycling Between Sediment and Water in Estuaries

Summary

The Joint Nutrient Study (JoNuS) was a Programme set up in response to international pressure to limit the risks of pollution due to excess nutrients entering the North Sea. Its purpose was to establish the nutrient status of UK Coastal Waters and was aimed at understanding nutrients in the southern North Sea, primarily in the Humber, Wash and Thames. Fieldwork took place between 1990 and 1993. This R&D Project covers the Environment Agency funded Ph.D. at University of East Anglia (UEA) which was a part of the JoNuS Programme. It provides some understanding of processes in estuaries, an essential feature of the JoNuS Programme.

The primary goal was to assess the behaviour of phosphorus in the intertidal areas of the Wash system. Experimental work focused on sediment samples from the Great Ouse and Nene estuaries, which drain to the Wash in Anglian Region.

These studies demonstrated that passive diffusion studies such as conventionally used in studies of fluxes from sediments, may not adequately mimic the environmental situation in intertidal systems since the regular tidal excursions can actively force exchange of overlying and pore waters at rates that could be 10 times those predicted from molecular diffusion. In the case of phosphorus, this active tidal pumping probably acts to increase the rates of diffusion of oxygen into the sediments and thus acts to retain phosphorus within the sediments rather than promote its release.

Following the successful completion of the JoNuS Programme, the Department of the Environment has already commenced funding of a second phase (known as JoNuS II), which concentrates on the nutrient status of the Thames Estuary and the Irish Sea.

Publishing reference: R&D Technical Report P40

Publication: R&D Technical Report P40: Best Management Practices to Reduce Diffuse Pollution from Agriculture

Summary

The Environment Agency has a duty to maintain and improve the water quality of controlled waters. To assist the Agency in this role, an R&D project was commissioned to identify best farming practice to reduce the impact of diffuse pollution on the aquatic environment.

A literature search and consultation identified the different methods used to reduce diffuse pollution. The focus of the consultations was to identify sites where best management practices (BMPs) were being used. From the identified sites, a selection of field visits were made and twenty-four BMPs which were "practical, low-cost farm management techniques effective in UK conditions" were identified. These BMPs were then priority-rated using a scoring system based on:

• which processes of diffuse pollution are targeted;
• pollutants and objectives which could be met;
• cost;
• design specifications; and
• effectiveness.

Examples of BMPs identified as being practical, low-cost and effective in UK conditions include: changing access points to fields, field application of pesticide residue, grassland rotation and riparian buffer strips. An A4 sheet was then produced, summarising each BMP, including: its purpose, problem indicators, application, specification, associated BMPs, implementation and management, and farm benefits.

Currently, the A4 sheets are provided in R&D Technical Report P40. The next phase of the project is to take these A4 sheets describing each BMP and produce a manual for use in the field by Water Quality Inspectors within the Agency.

Publishing reference: Environment Agency R&D Interim Report 639/1/A (Phase 1)

Report Title: The Impacts of Nutrient in Estuaries - Proceedings of the scoping workshop

Summary:

This report summarises the presentations and discussions of the Phase 1 (scoping) workshop at the Northminster House Offices of English Nature on 23/5/95. Specifically, it summarises four presentations given by guest speakers, on the effects of elevated nutrients on phytoplankton, on macroalgae, on more-oligotrophic estuarine ecosystems and in light-limited estuarine ecosystems. It then details the discussions that followed. This workshop identified the key areas of focus for the subsequent (Phase 2) detailed review of literature and expert opinion.

Publishing reference: Environment Agency R&D Technical Report P269 (Phase 2)

Report Title: The Impacts of Nutrient in Estuaries - Summary Report

Summary:

This report summarises the findings of the review of literature and expert opinion, and signposts the sections of the main R&D project record (P2/i639/1) where more detailed information can be found.

The report examines the factors which influence the nature of nutrient inputs to estuaries and the physical characteristics which determine the extent to which those nutrients are available for utilisation by the biological and chemical processes. It then reviews the different biological impacts of nutrients in estuaries, distinguishing between primary, secondary and tertiary impacts, and examines the scope for recovery.

The report notes the deficiencies in scientific understanding and relevant monitoring data, and consequently the apparent lack of examples of complete nutrient management strategies for estuaries. It focuses on the two key management requirements: a classification scheme, for coarse-screening the eutrophication-risk of estuaries and the establishment of estuarine Ecological Quality Objectives (EcoQO's). It builds these into a 4-stage process for managing estuarine nutrient impacts on water quality and conservation interest (screening to identify priorities, assessing, in detail, the status of those priority sites, setting specific objectives for the sites and taking/monitoring appropriate action.) The Environment Agency and English Nature are invited to trial this management approach, and to consider recommendations for further research to fill important gaps in their understanding.

Publishing reference: Environment Agency R&D Project Record P2/i639/1 (Phase 2)

Report Title: The Impacts of Nutrient in Estuaries Summary:

The complexity of dynamic and variable estuarine systems hinders a clear understanding of cause and effect, in relation to nutrient enrichment and eutrophication. The Agency and English Nature commissioned this review of literature and expert opinion, on the impacts of nutrients in estuaries, as an important step towards delivering the sound scientific foundations on which effective management strategies must be based, particularly in the context of EC Directive requirements (UWWT, Nitrates and Habitats).

The report examines the factors which influence the nature of nutrient inputs to estuaries and the physical characteristics which determine the extent to which those nutrients are available for utilisation by the biological and chemical processes. It then reviews the different biological impacts of nutrients in estuaries, distinguishing between primary impacts (on plant and particulate-bound bacterial communities), secondary impacts (deoxygenation) and more complex tertiary impacts (higher in the food chain). The report examines how an increase in nutrient status will tend to drive a stepwise shift in community structure from vascular plants, (seagrasses/saltmarsh) to phytoplankton, postulating that, once underway, such changes may be self-perpetuating, and hence not completely reversible without ecological intervention.

The report notes that we currently only have a partial, qualitative understanding of cause and effect, with respect to the impacts of nutrients in estuaries, and generally inadequate data, making it difficult to set meaningful chemical or biological monitoring criteria, or management targets. The report proposes a classification scheme, based on physico-chemical parameters, as a generic framework for coarse-screening eutrophication-risk. It also proposes that the development and testing of Ecological Quality Objectives, is the way forward in respect of target-setting. It is suggested that these two tools support a four-stage process for managing nutrient impacts on estuarine water quality and conservation interest. The four stages are: priority screening; detailed assessment of the status of priority sites; setting specific objectives for the sites; taking, and monitoring the success of, appropriate action. The Agency and EN are invited to trial this management approach, and to consider recommendations for further research to fill important gaps in their understanding.

Publishing reference: Environment Agency R&D Technical Report E54

Report Title: Trial Classification of Lake Water Quality in England and Wales: A proposed approach

Summary:

Standing waters (lakes, mires, pools and ponds) are an important component of the aquatic environment and have suffered a variety of impacts, the most significant of which have been acidification and eutrophication. Unlike flowing waters they have been less well monitored by successive agencies concerned with water and ecosystem quality and there was therefore a need to develop an appropriate classification and monitoring scheme. There are two approaches to classification: spatial state schemes and state-changed schemes. The spatial state approach divides lakes into essentially arbitrary classes, whereas the state-change scheme compares the current state with a base-line state which reflects the natural characteristics of climate, topography and geology. This report develops both approaches and outlines separate spatial state schemes which use nutrient-related variables (total phosphorus concentration, chlorophyll a concentration) or pH to categorise trophic status and acidity status, and separate state-changed schemes which measure the degree of eutrophication and acidification, respectively.

CDROM

Project Reference: EID (96)7

CDROM Title: Identification of blue-green algae of the British Isles

Summary:

The absence of appropriate keys is the main impediment to algological work. Whilst there are both beginner's guides and specialised taxonomic works (usually in foreign languages) there is no practical blue-green algal flora for the British Isles. This collaboratively-funded project with the University of Durham produced a guide to and keys for identification of UK blue-green algae to assist Agency staff engaged in monitoring work. The principal output is a interactive CDROM-based system built from LucID Professional, a specialised computer programme for developing biological identification systems. The system allows identification of 318 species from freshwater, brackish and marine environments and contains numerous images including photographs of algae under the microscope and in the field. The CDROM and a user manual is available to Agency staff and can be purchased from Durham University.