Scottish Government

APPENDIX 1: GUIDANCE ON SITE REPORTS

1. INTRODUCTION

The Pollution Prevention and Control (Scotland) Regulations 2000 require a site report to be submitted with an application for a permit to operate a Part A installation. Furthermore, a report is also required on permit surrender in order to ascertain that, upon cessation of activities, the site of the installation is returned to a satisfactory state.

1.1 Purpose and Scope of Guidance

This guidance has been produced by SEPA to assist those applying for a permit under the Pollution Prevention and Control (Scotland) Regulations 2000, with the requirement to submit a site report. This guidance applies to all installations required to submit a site report, excluding landfill sites. It does not cover the requirements of any prior investigation which may be required in connection with the disposal or tipping for the purpose of disposal of listed substances, although applicants may wish to include information obtained whilst undertaking a prior investigation in the site report.

The purpose of the guidance is to:

• outline the objectives and purpose of the site reports;
• highlight the methodology of the work underpinning the site reports;
• detail what should be included in the reports; and
• highlight technical references which provide more detailed guidance on work which is required to be undertaken.

The guidance is of an interim nature and will be subject to review and amendment, as appropriate. It should be noted that this guidance has no legal status: it has been issued to provide an indication to operators of SEPA's broad requirements, which may vary for individual sites. It is not intended that the document should be seen as prescriptive. Separate guidance is applicable in England and Wales.

1.2 Background to the Requirement for Site Reports under PPC

Schedule 4 to the Regulations, which relates to Regulation 7, requires that a site report describing the condition of the site of the installation be submitted with an application for a permit to operate a Part A installation. Throughout this document this is referred to as an Initial Site Condition Report. Regulation 15 indicates that an application for a surrender of a permit shall be accompanied by a site report. Throughout this document, this is referred to as a Closure Site Condition Report.

Regulation 8 requires that upon cessation of activities, necessary measures should be taken to avoid any pollution risk and to return the site of the installation to a satisfactory state. A satisfactory state, for the purposes of the Scottish Regulations, is taken to be the condition of the site immediately prior to operation under PPC. This is in line with the pollution prevention principle of the regime and it is therefore not appropriate to use suitable for use considerations.

Unless a discharge to land is granted in the permit, there should be no deterioration in the quality of the land and associated groundwaters at an installation over the duration of the permit. Practices should be adopted at an installation which will prevent release to land and subsequent discharge to groundwater. If land contamination occurs as a result of poor operational practices and unintentional releases, then the site will need to be restored to address any deterioration. Consideration of the site condition prior to operation and upon cessation of activity will enable a view to be taken on any deterioration of in the quality of land and associated groundwaters at the installation and any requirement for site restoration.

The following flow chart outlines the stages at which the site condition needs to be assessed. The site reports are required by regulation and provide a permanent record of factual information.

1.3 Relationship with other Legislation

PPC regulates land, water and air emissions arising from certain activities and installations, and requires that appropriate measures are taken to avoid pollution. Whilst the site report details the condition of the site, PPC does not consider whether the condition is acceptable: instead it records the condition so that any deterioration in condition can be identified and addressed. The question of whether the initial condition of the site is acceptable is the role of other legislation, as highlighted below:

• The planning system provides a mechanism for addressing land contamination issues upon change of land use, either prior to or following operation of an installation.
• The contaminated land provisions of Part IIA of the Environmental Protection Act 1990, require the remediation of land which is identified as contaminated on the basis of harm to key receptors, or pollution of controlled waters occurring, given the current site use.
• Integrated Pollution Control provides for action to be taken to remedy harm, including land contamination, caused by a breach of IPC controls.

The relationship between contamination addressed under the different regimes is outlined below for a process currently subject to Integrated Pollution Control (IPC) under Part I of EPA 1990, which will later become a Part A installation under PPC.

It should be noted that Part IIA seeks to address historical contamination and adopts a suitable for use, risk-based approach. This is considerably different to the no deterioration approach under PPC. The site report submitted in a PPC application may lead local authorities to identify land as contaminated under Part IIA.

1.4 Purpose and Objectives of Site Reports

The main purpose of the site reports is to provide a documented record of the site condition at a PPC installation. The objectives of the site reports may subtly differ from a typical assessment of contaminated land. It is the presence (or absence) of those chemicals associated with the PPC installation which is primarily of interest. Information contained within the site report may be used by SEPA, in combination with other information submitted with the application, to inform permit conditions to ensure protection of land and underlying groundwaters.

The objective of the initial site condition report is to detail the condition of land and associated groundwaters at the installation at the time the application for a PPC permit is made, in order to provide a reference point against which any deterioration can be assessed. The objective of the closure site condition report is to establish the site condition at the time that an application for surrender of a PPC permit is made, to inform of the need for and the requirements of site restoration. As highlighted in Regulation 15(3)(c), the closure site report will need to describe any changes in the condition of the site which have occurred since the application for the permit to operate the installation was made. The site condition reports should encompass the whole installation (process and agreed boundary), unless indicated otherwise by SEPA.

It should be noted that the reference point established by the initial site condition report will be revised if the condition of the site is later improved following any validated remedial action required by other legislation. Should an operator wish to submit a revised, substantiated statement of site condition in the light of new information, then contact should be made with SEPA. There is benefit is drawing SEPA's attention to new information that has a bearing on the condition of the site when this information becomes available, rather than upon closure. There is also merit in regular monitoring throughout operation of an installation, to provide a record of trends in land and groundwater quality.

If there is a significant change in the materials present at the site, contact should be made with SEPA, as a supplementary survey may be required to determine concentrations of the chemicals in land for which reference conditions have not been established. Where different chemicals are likely to be present on a site over time, consideration should be given to providing for this by analysing for the broad groups of chemicals likely to be present. This may prevent the requirement for a supplementary survey to be undertaken, to account for the introduction of new chemicals at a later date.

A site report is a technical document, which will be used to inform decisions made in relation to the issue and surrender of PPC permits. Site reports should therefore be compiled by suitably experienced and trained investigators.

1.5 Structure of Guidance Document

This guidance addresses the requirements of initial and final site condition reports in separate sections. Each section highlights the issues, which may be addressed by the report. These sections are supplemented by Appendices, which provide additional background information, highlight key information sources and suggest aspects to be considered in the preparation of site reports. It should be noted that those references mentioned do not constitute an endorsement by SEPA, and it is recognised that other reference sources of equal value are available.

2. INITIAL SITE CONDITION REPORT

2.1 Introduction

As stated above, the initial site condition report should detail the condition of the site at the installation immediately prior to operation under PPC. This information provides a reference point against which any non-permitted deterioration in land quality and associated groundwaters can be assessed. It is in an operators interest to conduct a comprehensive initial site condition survey to inform the initial site condition report. Contamination identified on closure of the installation, not recorded in the initial site condition report, will be attributed to operation of the installation under PPC, unless the operator can prove otherwise.

2.2 Outline Methodology for Establishing Site Condition

The operator must characterise the conditions at the site in such a way that enables changes which may result from operation of the installation under PPC to be detected. Any methodology for establishing the conditions at the site should include the tasks outlined in the following table.

The general logic of these tasks is that available information is collated and considered in order to determine whether there is sufficient information to come to a conclusion on the site condition. If not, then some form of site investigation is likely to be required, normally involving the collection of samples. In obtaining samples it is important to consider where to sample, at what depth to sample, how many samples to take, whether water should be sampled as well as land and what to analyse the samples for. The information arising out of the above then needs to be compiled into a report and a view taken on the site conditions. Further details for each of these tasks are provided in Sections 2.3 - 2.7, as indicated in brackets.

Given the scope of this document, it is not possible to cover all of the aspects described above in such depth as to enable an operator to decide on an approach to take. There is a wide range of published technical guidance documents relating to environmental reviews and the assessment of chemicals in land and groundwater. Whilst most of this guidance has been prepared to assist in other aspects of work, it still represents a valuable reference source for PPC site condition surveys. Appendix A provides a checklist for the various phases of work together with reference to some appropriate technical guidance documents.

The guidance below focuses on the objectives and issues which require to be considered in carrying out the various phases of work and is intended to allow the operator to take an informed, site specific view of the scope of work which is required. This current guidance does not seek to repeat available technical guidance on best practice approaches to the assessment of ground conditions.

2.3 Desk Study

The objectives of the desk study are :

• To prepare an inventory of the chemicals and wastes to be used and produced at site and to assess the potential for these chemicals to be discharged to land as a result of future site operations. This essentially comprises the production of a list, including quantities, of all the chemicals (or groups of chemicals) to be stored and used at the site, representing raw materials, by-products, products and wastes. The potential source areas for contamination and likelihood of emission should be established, along with details of measures adopted to prevent emission. The environmental significance of the chemicals (or groups of chemicals), including their hazardous properties, mobility and persistence, should be determined for the source areas identified.

• To assess the potential for chemicals to be present in the land and associated groundwaters as a result of the past use of the site. This would comprise a review of the site history to identify potential contaminants which could have arisen from the past use, and, in particular, highlighting the potential presence of any chemicals (or group of chemicals) which are to be used during the future operation of the site. Consideration should be given to subsurface structures or features such as drains which may contain residual chemicals from former site uses.

• To assess the environmental setting of the site in relation to the potential transport of chemicals from land to associated waters and derive a conceptual site model. This would comprise a review of information to assess the nature and likely permeability of underlying ground conditions (soils and solid strata) together with the general hydrological and hydrogeological conditions.

A checklist of potential information sources and technical guidance documents is provided in Appendix A. The following sources of information should ideally be referred to in the desk study:

• a full set of historical Ordnance Survey maps and plans;
• British Geological Survey (BGS) geology (solid and drift) and hydrogeological maps;
• available site investigation data, including divestiture/acquisition reports; and
• relevant information held by SEPA and Local Authorities.

The desk based research must be supplemented by a walkover survey to allow on-site inspection of potential source areas together with general observation of the environmental setting. Details of the types of information which should be recorded during the walkover survey are presented in Appendix A.

The desk study should result in a conceptual site model being developed, highlighting the relationship between ground conditions and any water bodies, in particular groundwaters. The model should consider the chemicals associated with the various source areas and their potential environmental fate upon release, given the underlying soils and solid strata (including groundwater). Any areas, or zones, of potential contamination should be identified, along with the likely contaminants and risk of emission associated with each zone.

2.4 Assessment of Requirement for Site Investigation and Design of Associated Sampling Strategy

On completion of the desk study phase, it will be necessary to review the results to assess whether a site investigation is required to establish the conditions at the site. If the desk study reveals sufficient information to enable both the operator and SEPA to be confident that the site condition can be established without the need for intrusive investigation, then further investigation will not be necessary. The need for an intrusive site investigation should be assessed on a case by case basis. Whilst investigation techniques are likely to be intrusive, in some circumstances it may be possible to use non-invasive techniques.

It is not possible to provide prescriptive guidelines on the precise level of investigation which will be required, as again, this must be determined on a site specific basis. The required level of work will be largely dependent on whether the installation is located on a "greenfield" or "brownfield" site and whether the installation, or a similar installation, has previously been operated at the site. An additional consideration is whether or not it is appropriate for groundwater, or indeed other water bodies, to be monitored as an indicator of land quality.

It is useful to adopt a staged, risk-based approached when considering these issues and determining the scale of investigation required, as indicated in the following flowchart and described in the subsequent paragraphs. It is also suggested that operators discuss their site investigation proposals with SEPA, before undertaking any investigative work.

The site investigation should primarily concentrate on the chemicals which will be associated with the PPC process. However, it will be in an operators interest to conduct as comprehensive as possible investigation, given the presumption that all contamination not highlighted by the initial site survey will be potentially attributed to operation of the process under PPC.

Stage 1: Requirement for site investigation

It may be that the review of preventative measures or the desk study provide sufficient information to characterise the site condition without the need for a site investigation. Should this be the case, the operator may propose a set of realistic, site-specific conditions (with statistical interpretation), derived from documentary sources, rather than to conduct an intrusive investigation at the site. However, as site contamination identified at closure of the installation, not recorded in the initial site condition report will be attributed to the operation of the installation under IPPC (unless proven otherwise), careful thought requires to be given to this approach.

In making a decision on whether there is a requirement for a site investigation, consideration should be given to:

• the degree of confidence in the preventative measures adopted in the past and the availability of records to substantiate these measures.
• the quality and availability of existing data on land quality, and whether this covers the range of potential contaminants associated with the proposed process.
• the possibility that the desk study research may have omitted to identify a previous contaminative use at the site; and
• the possible presence of contamination arising from off-site sources.

In view of the above operators may choose to carry out intrusive work to clearly establish initial site conditions.

For new installations developed on brownfield sites it would be expected that a comprehensive ground contamination investigation would have been undertaken before or during the planning process to identify potentially significant risks from the previous uses and, if necessary, for remedial action to have been carried out to prepare the site for its new use. As a result, data may be available which can be used in assessing the condition, such as that arising from remediation validation. However, the availability of this type of data may not negate the requirement to collect additional data to establish the site condition. In assessing whether or not additional data is required consideration must be given to the following:

• whether or not the previous site investigation has sufficiently characterised the chemical condition of the soils/made ground and any associated groundwaters beneath the site (in particular, if the site investigation was carried out some time ago is the quality of available data sufficient to satisfy current "best practice" requirements);
• whether or not remedial work carried out at the site has reduced contaminant concentrations;
• whether or not remedial or ground preparation works carried out after the site investigation works had introduced or exposed soils of unknown or poorly characterised chemical condition beneath the site; and
• whether or not the available chemical data included analysis of all of the chemicals (or chemical groups) which are to be used, produced etc. at the operating facility.

In view of the above, it cannot be assumed that a previous ground contamination investigation undertaken as part of the site redevelopment would fully satisfy the requirements of IPPC in establishing the initial site conditions.

For existing installations, it is envisaged that a site investigation will need to be undertaken in view of the fact that land may already be contaminated with chemicals associated with the installation. It is important that the site investigation seeks to distinguish between land contamination arising prior to operation of an installation under PPC and that which may arise during operation under PPC. Whilst it is recognised that there are practical difficulties associated with undertaking investigations on operational sites, it is expected that efforts will be taken to minimise any limitations. The provision of documentary evidence regarding operational practices may well address any deficiencies in an investigation.

Some operators of existing installations may wish to provide an estimate of the site condition based on existing information, particularly where they intend to develop the site upon cessation of activities. Any estimation of site condition should be as realistic as possible and should not seek to over-estimate any contaminants present. It is possible that many sites will have had some form of investigation undertaken at some stage in their history of operation. However, when considering establishing the site condition by reference to such investigations, the points highlighted above in relation to new installations at brownfield sites must be considered.

Stage 2: Areas on Site to be Investigated

The areas on site to be investigated should be determined on a site by site basis. However, it is anticipated that most sampling strategies will include targeting those areas of the site which would be anticipated to be at most risk from becoming contaminated as a result of the future operation of the facility (potential source areas). It is anticipated that the potential source areas will comprise hazardous materials handling/storage areas, waste handling/storage areas, drainage systems, washing down areas and areas where dust could accumulate. For existing sites it is recognised that not all of these areas may be practical or viable to investigate. However, it is not expected that such constraints will prevent the majority of potential source areas from being investigated and the site being characterised sufficiently so that a reference point can be established.

Whilst the potential source areas may currently be considered to be uncontaminated, it is important to characterise them in order to distinguish between initial site concentrations and any contamination arising during operation of the installation. An indication of the typical areas to investigate is provided in Appendix C. It is recognised that not all of these areas apply to every installation and that some installations may have additional areas, which require investigation. Furthermore, whilst sampling should ideally be biased by the actual installation at the site, other methods for determining areas to investigate may be equally valid.

The design of any soil sampling strategy should take into consideration the previous use of the site. The sampling may focus on simply establishing background soil conditions at a "greenfield" site, but will need to address a potentially more complicated situation at a "brownfield" site or an existing installation. Where similar chemicals have been historically stored and handled at a site, then the investigation should also encompass these areas of potential contamination. In some cases, there may be benefit in some random sampling across the site.

Stage 3: Sampling and Analytical Strategy

The sampling strategy should ensure that representative samples (soil, and possibly gas and water samples) are taken to delineate land contamination, both across the site areas investigated and at depth. In some situations, it may be prudent to undertake a shallow sub-surface investigation before determining whether a more detailed deeper sub-surface investigation is required. The vertical extent of the investigation will largely depend on the mobility of the chemical contaminants and the permeability of underlying strata, which will have been determined in the desk study. The location and accessibility of sampling points should be determined, bearing in mind that when a report is required on closure, return to the same locations will provide the opportunity for the most appropriate comparison.

Under certain conditions, groundwater quality can act as an indicator of land quality. This depends on several key factors, including:

• how contaminants would be anticipated to be transported within the soils/rock above the water table (the unsaturated zone) i.e. are the properties of both the potential contaminants and the strata above groundwater such that contamination introduced into the soil would be expected to migrate down to the groundwater beneath the site.
• how contaminants would be anticipated to be transported within the groundwater beneath the site i.e. are the properties of both the contaminants and the aquifer such that monitoring of point locations within groundwater beneath the site would be expected to detect the presence of contaminants which had been introduced into the groundwater,
• whether or not groundwater is already contaminated (in which case it may be difficult to clearly establish whether or not any additional loading of contaminants had occurred); and

It is recognised that there are a number of advantages to the operator in adopting groundwater monitoring, in addition to soil monitoring, as a means of establishing initial site and closure conditions:

• on some sites it may reduce the requirement for collecting and analysing soil samples;
• the sampling location is constant, the medium being sampled relatively homogeneous and samples can be easily obtained;
• the installation of groundwater monitoring wells would provide operators with the opportunity to implement a programme of groundwater monitoring during the operation of the installation. This would provide an early indication of any on-site problems which require to be addressed together with information on the possible inward migration of contaminants from an off-site source. This monitoring data could be included in the closure site condition report.

In exceptional circumstances, surface water and sediment quality can also act as an indicator of soil quality. However, surface waters and sediments tend to be a less reliable indicator than groundwaters of soil quality. Key considerations are the hydraulic continuity between surface and groundwaters and other discharges to the surface water body. For static surface water bodies i.e. lochs, ponds etc. contaminants may be retained within the water body whilst for rivers, streams etc. contaminants are likely to have been transported away from the site and in this case samples of residual contamination in bed sediment may be more appropriate.

It should be recognised that surface water and groundwater monitoring does not provide a sole means of establishing initial and closure site conditions. Some soil samples will still be required, given the time taken for contaminants to migrate through the unsaturated zone and to enter water bodies.

A key question in any strategy is not only what to sample and how many samples to obtain, but what to analyse the samples for. For some sites with a limited number of chemical materials, it will be possible to analyse for all of the chemicals. For many sites, the adoption of screening analyses for broad groups of chemicals may be appropriate, with more detailed analysis undertaken only if the screening results show a need for this. It should be noted that solvent extractable matter is unlikely to be acceptable as a screen for organic compounds.

Even screening analyses may not be feasible for complex sites where thousands of chemicals may be present. For complex sites a pragmatic approach may be acceptable whereby information obtained in the desk study on the quantities present, the likelihood of emission and the environmental significance of the chemical is used to determine the most significant chemicals and hence the analytical strategy. In such cases, it is important to highlight the chemicals included in the analytical strategy and to justify the basis on which chemicals were included or excluded.

2.5 Implementation of Site Investigation and Analytical Works

Once the sampling strategy has been established, the key elements of the subsequent site investigation will vary depending on the required scope of work. The key stages typically comprise:

• selection of appropriate investigation and sampling techniques e.g. trial pits, cable percussive boreholes etc.;
• design of sampling and analytical schedule;
• preparation of health and safety plan; and
• onsite implementation.

Appropriately trained and experienced personnel must be available to carry out the various stages of work. Further guidance is provided in Appendix A.

2.6 Establishment of Site Condition

The data obtained during the review of preventative measures, desk study and site investigation needs to be interpreted and the site condition established. An essential part of establishment of the site condition is the development of a conceptual site model of the geology, hydrogeology and chemical conditions at the site. Where appropriate, this model should identify a number of distinct areas or zones and conditions should be assigned to each zone, rather than providing an average condition of the site. Consideration should be given to the following:

• Soil Type and Ground Conditions: these influence chemical mobility and potentially background concentrations. It is therefore important that the major soil types and ground conditions at the site are identified, particularly given the heterogeneous conditions typically encountered at sites. The general ground conditions, including made ground, should be described based on all of the data obtained during the desk study and any intrusive investigation. Detailed consideration should be given to each of the source areas, with the soil types encountered in the source areas set in the context of the general ground conditions.

• Likelihood of Emission: the areas on site which are most likely to be, or to have been contaminated should be highlighted, along with the potential extent (vertical and lateral) of contamination and details of the contaminants.

• Soil Chemical Concentrations: these should be presented for each source area (or zone), accounting for heterogeneous ground conditions, either based on data collected for the purposes of PPC or data available from other sources. The basis on which the concentrations have been derived should be clearly presented. There will always be variation in chemicals concentration due to site heterogeneity and sampling and analytical errors. The degree of uncertainty associated with any data present should be highlighted and justified, along with the statistical basis on which chemical concentrations indicative of site condition were derived.

• Groundwater Chemical Concentrations: these should be present when chemical contaminants in soil have the potential to impact on groundwater quality, with an indication of how the concentrations have been derived. If variable groundwater conditions are encountered, then interpretation should be provided as to why this may be the case. Interpretation should also be provided regarding potential for inward migration of contaminants from off-site sources, if this is considered to be an issue.

Following development of the conceptual site model, it should be possible to detail a set of realistic, site-specific conditions. The basis on which these have been established should be apparent, including statistical interpretation. Further information may be required if the site condition is not adequately substantiated.

2.7 Preparation of the Initial Site Condition Report

The report detailing the assessment of the initial site condition requires to be submitted to SEPA on application for a permit. This report should present the site conditions in a clear and unambiguous manner, together with details and justification of the methodology adopted and data on which the assessment has been based. The precise content and structure of the report will depend on the scope of work which has been carried out and would be expected to include the following:

• a brief description of the site location (including grid reference), site boundary, topography and layout (to be accompanied by a clear site plan);

• a description of the history of the site broken down into the history of it's current use (if any), any other previous historical use and the historical setting of the site;

• the results of the desk based assessment of potential contaminants associated with the past use of the site, including consideration of the likelihood of emission and any previous site investigation data (a copy of any available previous site investigation report to be included as an Appendix);

• a description of the proposed operating facility and associated processes including, in particular, a list of all chemicals (or chemical groups) which will be used and the likelihood of emission. A description of the areas of the site in which chemicals of concern will be handled and stored (to be referenced to detailed plans submitted with the application) should be provided, along with an indication of the mobility of the chemicals;

• a conceptual model incorporating a description of the environmental setting of the site. This should include information on the geological, hydrogeological and hydrological conditions of the site and surrounding area, as well as highlighting potential areas of contamination;

• a summary description of the methodology adopted by the operator in establishing the initial site conditions at the site and the reasoning behind that adoption;

• where site concentrations are proposed on the basis of documentary evidence a clear statement on the source, quality and appropriateness of that data in relation to the soil conditions anticipated beneath the site (to be supported, where practical, by copies of the original source data as an Appendix);

• where undertaken, a description of the intrusive site investigation sampling methodology which will include sample handling procedures, well design details etc. and procedures which were adopted to prevent cross contamination (to be supported by a site plan showing sampling locations and logs of the soil conditions encountered during the investigation);

• where undertaken, the results of the chemical analytical testing schedule (including a copy of the original laboratory test certificates together with the testing methodology, indicating limits of detection, accuracy and precision);

• observations arising from the walkover survey and any site investigation works;

• statistical methods applied in interpreting site condition data; and

• a clear and substantiated statement of the site condition against which any deterioration can be assessed.

A proposed structure of the site report is presented in Appendix B. It is recognised that inclusion of certain information in the report may duplicate that presented elsewhere in the application. Operators may wish to cross-reference sections of the report to other aspects of their application. However, consideration should be given to duplicating information if this improves the clarity of the site report. Consideration should also be given to including plans, drawings and photographs where appropriate.

3. CLOSURE SITE CONDITION REPORT

3.1 Introduction and Outline Methodology

The aim of the closure report is to detail the site condition at the time that an application for surrender of a PPC permit is made, to inform the need for and the requirements of site restoration. In many circumstances, subject to the requirements of permit surrender, it is anticipated that the site report will be submitted after decommissioning and demolition. If the report is submitted prior to decommissioning or demolition works, then further work may be required to report on the site condition following such activity. If restoration work is required, a report briefly detailing the work undertaken may also be required to be submitted. Restoration of a site must still be addressed if SEPA chooses to revoke a permit.

The Closure Site Condition Report should identify any changes in the condition of the site as described in the site report accompanying the application for a permit to operate the installation. The basic methodology for establishing the closure conditions at the site is likely to comprise the following tasks:

Further details for each of these tasks are provided in Sections 3.2 - 3.7. These sections highlight objectives and issues specific to site closure and build on the concepts introduced in Section 2. Reference should therefore be made to Section 2 and Appendix A.

3.2 Desk Study

The desk study will essentially comprise an updated review of the documentary research carried out for the initial site condition survey, together with: a walkover survey; a review of relevant elements of the operational history of the site; and a review of statutory information submitted under the PPC regime e.g. knowledge/evidence of past spills, accidental leakages, change in materials etc. There will be considerable scope for using the findings of environmental reviews and audits in undertaking the desk study.

Information sources to be referenced in the desk study should include:

• Key site records which are relevant to establishing site conditions, such as maintenance records, environmental audits, compliance records, reviews of performance, level survey etc.;
• Key monitoring records which are relevant to establishing site conditions;
• Incident reports, including those from fire and emergency services;
• Site layout plan, highlighting any changes to the plan originally submitted; and
• A summary of the nature and quantities of chemicals handled on site

Key records may provide the only evidence as to the operation of the installation under PPC and may therefore be essential to refer to when considering any change in site condition. The importance of accurate records to substantiate environmental performance cannot be overstated.

The conceptual site model developed in the Initial Site Condition Report should be reviewed, with particular consideration being given to the potentially contaminated areas to assess whether they are likely to be contaminated.

3.3 Assessment of Requirement for Site Investigation and Design of Associated Sampling Strategy

On completion of the desk study, it will be necessary to review the findings and assess whether further action is necessary to characterise the site condition. If the desk study reveals sufficient information to enable both the operator and SEPA to be confident that the site condition can be established without the need for intrusive investigation, then further action will not be necessary. An operator would have to provide strong evidence that the site had not become contaminated under PPC, where it was not intended that this would be confirmed by sampling results. For the majority of installations, this is unlikely to be the case and the scale of site investigation required to characterise the condition at the site should be considered.

Those areas most likely to have been degraded during the operational history of the site will have been identified in the desk study. An investigation should then be designed to establish the ground conditions present in each of these areas. In addition, some investigation of areas anticipated to be uncontaminated should also be undertaken to confirm the conditions present in these areas. It is not possible to provide prescriptive guidelines on the precise level of ground investigation which will be required as this must be determined on a site specific basis. However an indication of the areas most likely to require investigation is provided in Appendix C.

As with the initial site condition survey, it is useful to adopt a staged approach when considering the extent of the investigation (refer to Section 2.4 for further details). It is envisaged that some form of intrusive investigation will be required for all installations, unless it can be shown otherwise that the quality of land and associated groundwaters has not deteriorated as a result of operation of the installation.

3.4 Implementation of Intrusive Site investigation and Analytical works

As with the initial site condition survey (Section 2.5), once the sampling strategy has been established, the key elements of the subsequent intrusive site investigation will vary depending on the required scope of work. The key stages typically comprise:

• selection of appropriate sampling and investigation techniques e.g. trial pits, cable percussive boreholes etc. In selecting the appropriate technique consideration will need to be given to the presence of buried services, drains, below ground tanks, foundations and access for plant and available headroom.

• considering the statistical basis of the investigation and ensuring that it is comparable to the initial site condition survey. Where possible, the same "zones" should be sampled using comparable sampling, analytical and statistical interpretation techniques to those used in the initial site condition survey;

• design of analytical schedule. This should be similar to the initial site condition schedule but will need to be refined to accommodate any changes in materials handled during the operational history of the site

• preparation of health and safety plan; and

• on-site implementation.

Any closure investigation should ideally share the same statistical basis and use comparable sampling and analytical techniques as the initial investigation, to enable changes in site condition to be established. Appropriately trained and experienced personnel must be available to carry out the various stages of work.

3.5 Establishment of Closure Condition and Reference to Initial Site Condition

The data obtained during the review of the preventative measures, desk study and site investigation should to be interpreted and the closure site condition established. Consideration should be given to the basis on which the initial site condition was established (see Section 2.6). The closure condition should be referenced to the initial site condition and the operator should provide justification as to whether or not there has been a deterioration in the quality of land and associated groundwaters. The statistical basis of any decision made should be clearly demonstrated. Where non-permitted emissions to land have occurred, but no deterioration is anticipated due to natural attenuation, then evidence should be provided that this is the case.

Where a significant deterioration has occurred, which was not part of a permitted discharge, details should be provided of the measures which are proposed to be taken to return the site to a satisfactory state. It should be noted that suitable for use considerations are not appropriate and any restoration under PPC should seek to return the site to its initial condition. However, SEPA is required to have regard to the costs and benefits of such action, so there will be some element of reasonableness when considering restoration requirements. Operators are advised to consult with SEPA before undertaking restoration work. Some operators may wish to undertake restoration as part of site redevelopment. Where this is the case, the surrender of the PPC permit will not be accepted until the development has returned the site to a condition which meets PPC satisfactory state requirements.

If improvements in analytical techniques have resulted in lower limits of detection, so that a chemical previously undetected is now detected, then in most cases the threshold of deterioration will be the statistical variation applied to the results from the Initial Site Condition Report. It will be left to the operator to demonstrate that any significant deterioration is not attributable to an installation being operated under PPC. Clear evidence should be provided, and the reasons for the change in the quality of land and associated groundwaters indicated.

3.6 Decommissioning Proposals

Details of the measures to be taken to avoid any pollution risk need to be provided. This should include the emptying and cleaning of tanks, the cleaning of drains, removal of chemicals from site, protection measures for chemicals left on site and decontamination of the site structure. Further, more detailed, guidance on the requirements of decommissioning are provided in the CIRIA document Remedial Treatment for Contaminated Land Vol II (see Appendix A).

3.7 Preparation of the Closure Site Condition Report

The site closure condition report must clearly set out the site conditions on closure and refer these to the initial site conditions. In addition, it should provide details of the operational history of the site under PPC, including changes in ground level, from the issue of the permit to closure and the current conditions. Similar methods should be adopted on closure to those used in preparation of the Initial Site Condition Report, to ensure a true comparison. The report should:

• detail any revision made to the initial site condition;

• provide additional information on the site layout and operation, where details differ from those supplied in the initial site condition report;

• provide details of the chemicals (or chemical groups) which were used together with a description of the areas of the site where chemicals of concern were handled and stored and how they were transported around the site (to be supplemented by a plan showing the location of the areas described);

• review the operation of the site under PPC and detail potential releases to land arising from spills, fires etc. Consideration should be given to housekeeping practices at the site and to the findings of any environmental audits or other site records. Attention should also be given to accumulations of potentially contaminating material on site (dust etc.), as well as the integrity of tanks, other storage vessels and drains;

• consider the desk study conducted for the initial site condition report and highlight any changes or additional information;

• a summary description of the methodology adopted in assessing the site condition and the reasoning behind that adoption;

• if undertaken, a description of the intrusive site investigation sampling methodology which will include sample handling procedures, well design details etc. and procedures which were adopted to prevent cross contamination (to be supported by a site plan showing sampling locations and logs of the soil conditions encountered during the investigation);

• where relevant, tables showing exploratory hole number, the reason for the exploratory hole, initial site conditions and final site quality conditions, to allow direct comparison of the conditions on the site before and after operation of the installation under PPC;

• the results of any chemical analytical testing undertaken (including a copy of the original laboratory test certificates together with the testing methodology, detailing limits of detection, accuracy and precision);

• statistical methods applied in interpreting site condition data;

• observations arising from the walk over survey and during site investigation works;

• a clear statement of the site condition , how it has been assessed and whether there has been a significant deterioration in condition during operation of the installation under PPC;

• where applicable, proposals for site restoration to ensure that it is returned to a satisfactory state; and

• proposals for site decommissioning, to avoid pollution risk.

A proposed structure of the site report is presented in Appendix D.