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Further description:- United Kingdom  Site investigation 

Glossary Entry:- United Kingdom  Site investigation
Site investigation describes the process of carrying out investigations on land to determine whether 
there is contamination present and to collect sufficient, suitable data for the purpose of risk assessment.
The investigation is normally carried out in several stages. These stages range from a desk study
and simple visual inspection to full intrusive investigation using trial pits and boreholes etc
and the sampling and analysis of materials.
Overview
Official guidance in the UK, such as 'CLR11 Model procedures for the management of land contamination' 
published by Defra and the Environment Agency, shows how site investigation is used at various stages
of the risk management process to collect information about a site, relevant soil and groundwater
processes, and any contamination present. A wide range of techniques and methods for gathering site data are available within the UK. However,
it is essential that any site investigation is designed based upon the available Conceptual Site
Model and will produce sufficient quantity and quality of data. Usually, this data is required to
inform further risk assessment.
1. General Approach
 
  
The UK has adopted a risk-based approach to the identification, assessment and management of contaminated 
land, which embraces the source-pathway-receptor concept. Consequently the process of site characterisation
is strongly linked to the risk assessment process, and in most cases site characterisation is driven
by the need for additional data within the risk assessment. As with most aspects of the risk assessment process in the UK, site characterisation is usually
implemented in a staged manor. These stages typically consist of :
  • Phase 1: desk study, site walkover and qualitative risk assessment
  • Phase 2: intrusive investigation and quantitative risk assessment. This may also be implemented
    in a number of stages or separated in to various zones. Phase 1 The first phase of site characterisation usually involves a deskstudy to collect and collate
    relevant information from a variety of sources relating to the geological and hydrological setting
    of the Site (i.e. the nature of the ground beneath the site and of local ground and surface water) and
    the historical uses of the site (i.e. likely contaminants and activities). This is likely to involve
    multiple sources of information including, for example, Ordnance Survey maps, geological and groundwater
    vulnerability maps, aerial photographs, local and national archives and newspapers, registers
    held by relevant regulatory agencies and interviews with former staff, neighbours or regulators
    etc. This review is intended to identify likely sources of contamination, receptors and pathways
    at the site that will be investigated in more detail during later stages of the risk assessment process.
    However, it also assists in identifying any health and safety requirements for on-site activities.
    Subsequent to the desktop study, a site walkover is usually performed. This is intended
    to obtain details that were not documented elsewhere. A walkover survey will usually provide details
    of the current condition of the site, such as evidence of potential contamination and site environmental
    practices, and may include a photographic record. The output of a phase 1 excersise is usually an interpretive report that contains a summary of the
    site’s setting and history and a qualitative risk assessment, including a conceptual site model,
    that describes the potentially significant pollutant linkages at the site and the uncertainties
    and assumptions made. Phase 2 The second phase of site characterisation usually involves an intrusive site investigation,
    which involves the analysis of soil, water and/or gas samples. The design of the investigation is
    usually based on the initial conceptual site model contained within the phase 1 report and is specifically
    aimed at addressing the uncertainties and assumptions identified. The following activities need to be carried out during a site investigation (Barr et al., 2002):
  • Setting the objectives of the site investigation (based on conceptual model developed from
    desk study and inspection)
  • Deciding what, where and how deep to investigate
  • Deciding whether to use geophysics
  • Selecting methods of intrusive investigation
  • Designing sampling strategy
  • Designing analytical strategy
  • Executing the site investigation
  • Refining the conceptual model
  • Carrying out a risk assessment
  • Producing a report including updating the conceptual model Site investigation objectives should reduce the limitations and uncertainties of the conceptual
    model developed from desk study and walkover survey or from any previous site investigations. The
    objectives should be specifically tailored to the site in question. Rather than general statements,
    the objectives should refer to specific issues as highlighted in Table 1. The objectives should be
    clearly stated and the report should show how they have been addressed. Table 1: Site investigation objectives (After Scottish Executive, 2002)

    Is there a source of contamination?

    • Is diesel present beneath the former tank or pipework?
    • Did fugitive dust from the site cause cadmium to be deposited in adjacent gardens?
    • Does the house dust contain high concentrations of lead?

    How big is the source of contamination?

    • What is the shape and size of the plume of dissolved chlorinated solvent?
    • How deep did the PCB contaminated oils penetrate the unsaturated zone?

    Is there a pathway by which the contamination might migrate?

    • What is the nature, lateral continuity and thickness of the sand horizon and may it allow landfill gas to migrate as far as the nearby houses?
    • How long will it take the chlorinated solvent to penetrate the clay layer and reach the aquifer?

    Has the contamination actually reached the receptor of concern?

    • What is the blood-lead concentration of young children living near the smelter?
    • What is the concentration of dioxins in the poultry?
    The variability of contaminated sites, and consequent potential for variability in results is
    high. Site investigation needs to be designed to capture representative information about all relevant
    aspects of the site. A wide range of statistical techniques and other approaches to obtaining corroborative
    evidence may be needed to ensure that the site characterisation data are fit for the purpose of risk
    assessment.
  •  
    2. Policy and Regulation
    2.1 Policy
     
      
    UK policy and guidance on the risk assessment of contaminated land has developed swiftly since 
    2000, driven by the implementation of new legislation designed to address contaminated land, such
    as Part IIA and changes to the planning and building control systems. This developing policy has been
    published by various authoritative bodies in a number of guidance or decision support documents.
    Earlier guidance, published by CIRIA (Harris et al., 1995), Scottish Enterprise (1998) and the
    Welsh Development Agency (1993) etc., did not adequately emphasise the central role of the conceptual
    model in the design, reporting and interpretation of site investigations. Nevertheless this guidance
    contains many practical details that are not found in subsequent documentation. A number of documents have been published by the Environment Agency including 'Secondary Model
    Procedure for the Development of Appropriate Soil Sampling Strategies' (Environment agency, 2000).
    British Standard 10175 (BSI 2001) sets out a framework for the design, execution and reporting
    of site investigations of potentially contaminated land. Adherence to British Standards, such
    as BS10175, is one of the basic definitions of 'good practice'. More recently CIRIA has published
    focused reports describing the applicability of biological and non-biological methods of characterisation
    (Finnamore et al., 2002; Barr et al., 2003) and geophysics (McDowell et al., 2002).
     
    2.2 Regulation
     
      
    There are two principal pieces of legislation that have a bearing on the risk management of land 
    contamination, and therefore on site investigation. These are the Town and Country Planning Act
    1999 supported by Planning Policy Statement 23 and the Contaminated Land Regulations that enable
    Section Part IIA of the Environmental Protection Act 1990. Further details can be found in the General Resources pages which are accessible from the United
    Kingdom Home Page
     
    3. Funding
    Site Project Funding
    
    
     
            
    R&D funding
    Soil Protection
    Research Type: Applied

    Topics: Brownfields Contaminated land, Contaminated land overview Contaminated land, Remediation options, Remediation options overview Groundwater protection, Groundwater protection overview Soil, Soil Overview

    Submitted by: Maike Hauschild  Who does what?

    Full Details |


    Soil Biodiversity Programme
    Research Type: Basic

    Topics: Brownfields Contaminated land, Contaminated land overview Contaminated land, funding Soil, Soil Overview

    Submitted by: Maike Hauschild  Who does what?

    Full Details |


    URGENT (Urban Regeneration and the Environment)
    Research Type: Basic

    Topics: Brownfields Contaminated land, Contaminated land overview Contaminated land, funding Groundwater protection, Groundwater protection overview Soil, Soil Overview

    Submitted by: Maike Hauschild  Who does what?

    Full Details |


    'Infrastructure and Environment' programme and 'Engineering' programme
    Research Type: Basic

    Topics: Engineering, Infrastructure and Environment, Brownfields, Contaminated land, Groundwater protection, Funding, Brownfields Contaminated land, Contaminated land overview Contaminated land, funding Groundwater protection, Groundwater protection overview

    Submitted by: Maike Hauschild  Who does what?

    Full Details |


    Bioremediation LINK Programme
    Research Type: Applied, Basic

    Topics: (1) To understand and exploit natural attenuation in groundwater and soil (demonstration, modelling, prediction, definition of operating window). (2) To improve engineered in-situ bioremediation, interfacing microbiology with engineering and hydrogeology; dealing with heterogeneity, improved process control and optimisation. (3) To translate the results of laboratory studies into the field (scale-up). (4) To position bioremediation within a risk management framework - bioavailability, risk-based end points and residue behaviour. (5) To develop the ability to monitor in-situ microbial processes. (6) To understand the constraints on in-situ microbial processes. (7) To integrate bioremediation with other technologies. (8) To quantify human health impacts of bioremediation and develop surrogate testing. (9) To address socio-economic issues- perception of bioremediation technologies and decision-support mechanisms.

    Submitted by: Professor Paul Bardos  Who does what?

    Full Details |


    Land Contamination
    Research Type: Applied

    Topics: site assessment for land contamination, decision support tools for risk management, remediation of contaminated soils, sediments, and groundwater, Brownfields Contaminated land, Contaminated land overview Contaminated land, funding Groundwater protection, Groundwater protection overview

    Submitted by: Maike Hauschild  Who does what?

    Full Details |


    Defra Web Page on: Contaminated Land - funding
    Research Type: Demonstration

    Topics: There are several measures which support the clean up of contaminated land, and these are described on this web page

    Submitted by: Professor Paul Bardos  Who does what?

    Full Details |



    Market Information
    
    
     
        
    4: Management tools / decision support and guidance

    No further information available

    5. Authors
    
    
     
        
    6. Acknowledgements
    Based on the article Nathanail & Nathanail (2003)'Risk-based site characterisation', Waste Management, 
    October 2003, P49-50