Further description:-  Strategies 

Glossary Entry
Risk management strategies are the approaches employed to control risks from contaminated sites, 
and remove them or reduce them to acceptable levels
Further description author's instructions

1 Use of a Site Conceptual Model

 

It is increasingly common now to see a holistic approach to contaminated land management with site investigation, risk assessment and risk management activities and decisions taking place in an iterative way.  At the heart of any site management work must be the derivation of a site conceptual model (SCM).  The SCM integrates what is already known about a site, identifies what still needs to be discovered, and how site information should be used. The SCM sets out the critical pollutant linkages of concern for a particular land contamination problem.  It crystallises understanding of what needs to be done to achieve risk management, and from this point appropriate remediation techniques for those risk management goals can be chosen.  The SCM should be established at the earliest possible stage of information gathering for a site, and then gradually extended and adapted as more information becomes available and as subsequent remediation activities take place.  while site appraisal is still continuing.  As remedies are considered site investigation can be adapted to provide better information to optimise remediation planning.  Decision making can use pollutant linkages as an underpinning discipline.  Click here for further information:

 

 

2  Limitations of the risk management approach

 

While risk based decision making is used for managing historic contamination, this does not necessarily apply to contamination taking place now or in the future.  Across the European Union legislation has been or is being enacted to ensure that potentially polluting industrial and waste management processes are managed to reduce environmental emissions to acceptable levels, known as Integrated Pollution Prevention and Control (IPPC). In many European countries, remediation to pre-contamination levels may be required where contamination occurred on IPPC regulated site. 

 

The effectiveness of risk based decision making is, in general, limited by the perceptions of different stakeholders involved with the contaminated land in question.   A common manifestation of this is a desire for total removal of contamination whatever the cost.  This may be the view of an affected householder, but it is a surprisingly frequent commercial view as well.  Potential purchasers or developers of sites do not want to take the financial risk that residual contamination in a treated site might cause future problems, necessitating further costly remediation.  This has in many cases lead to excavation and removal offsite being the only acceptable remediation solution.  However, faith in excavation and removal off site of areas found to be impacted by contaminants offering a complete elimination of contamination can be  mistaken.  Any remediation project is fundamentally limited by the quality of the site investigation.  If contamination has not been found, then it will probably not be remediated, unless by a fortuitous coincidence.  Furthermore, a number of contamination problems cannot be fully managed by excavation based responses, in particular where groundwater contamination with DNAPLs has taken place.

 

 

3  Risk Based Land Management

 

Risk Based Land Management (RBLM) is a concept developed in the late 1990s and early 2000s by an European working group funded by the EC, CLARINET, http://www.clarinet.at.  The concept is likely to have a major bearing on contaminated land management and policy.  

 

Risk Based Land Management is primarily a framework for the integration of two key decisions for remediation of contaminated land:

·        The time frame: this requires an assessment of risks and priorities, but also the consideration of the longer term effects of particular choices.

·        The choice of solution: this requires an assessment of overall benefits, costs and environmental side effects, value and circumstances of the land, community views and other issues.

 

These two decisions have to take place at both an individual site level and at a strategic level, especially as the impact of contaminated land on the environment can have not only a large scale regional dimension but also potentially wide ranging long term impacts. The decision making process needs to consider three main components which form the core of the RBLM concept:  (1) fitness for use, (2) protection of the environment and (3) long-term care, as illustrated in Figure 1. The first two describe goals for safe use of land, including prevention of harm and resource protection. The third allows for a more rigorous assessment of the way in which these goals are achieved, to ensure that it is a sustainable way.   The three components need to be in balance with each other to achieve an appropriate solution.

 

 

Figure 1 The main components of Risk Based Land Management (from CLARINET)

 

 

Acknowledgement

 

Extracted from Nathanail & Bardos, (2004) “Reclamation of Contaminated Land  ISBN 0471985600

http://www.wileyeurope.com/WileyCDA/WileyTitle/productCd-0471985619.html

 

 

 

Authors
Paul Bardos
r3 Environmental Technology Limited, United Kingdom

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