Index > 2 Development of a strategy, implementation and execution program to remediate radioactively contaminated sites >

2.2.1 Major steps in a remediation program

Contents Introduction Potential human health and ecological impacts Public perception and response to the problem Likely permanence of adverse effect of contamination The potential for spread of contamination Established radiological and other criteria Potential for trans-boundary effects Availability of technological solutions and resources Financial capability Lessons learned Introduction

Environmental remediation should commence with a planning stage [IAEA – 1999b]. Matters which should be considered first, i.e., at the very beginning of the planning stage, should include the following:

  • Potential human health and ecological impacts;
  • Public perception and response to the problem;
  • Likely permanence of adverse effect of contamination;
  • Potential for spread of contamination;
  • Established radiological and other criteria;
  • Potential for trans boundary effects;
  • Availability of technological solutions and resources;
  • Financial capability;
  • Lessons learned.

The preparation of a program plan is linked to a number of other activities. The general elements of an actual environmental restoration program may comprise:

  • Preparing the program plan;
  • Establish stakeholder involvement;
  • Perform a historical site assessment;
  • Conducting a radiological site characterization;
  • Establishing remediation criteria;
  • Selecting the remediation approach;
  • Implementing remediation activities;
  • Conducting post remediation activities;
  • Considering special aspects;
  • Establishing a quality assessment program;
  • Reporting and archiving.

Each of these elements requires pre-planning. It is helpful to prepare reports which detail all the supporting activities related to these elements before significant levels of funds and efforts are committed. The preparation of this program plan will usually require several iterations. A number of preliminary choices or strategic decisions will have to be taken as the plan is developing. Potential human health and ecological impacts

The remediation plan and associated monitoring requirements should be designed and implemented so as to identify possible adverse health and environmental effects of the contaminants and to optimize protection. These considerations apply to the workers performing the remediation, to the public and to the environment.
To achieve the objectives of an environmental remediation, decisions should be taken concerning the following:

  • The schedule and sequence of the remediation activities;
  • Operational quantities (e. g., instrument readings corresponding to the reference levels);
  • The criteria for the termination of remedial actions;
  • Post-remediation conditions with regard to access to or use of the site.

Dependent on the scale of contamination, remediation of sites may be prioritized following a hazard assessment and reduction process. Political considerations, funding considerations, logistical considerations and public input may play another important role, however.

Considering public health and ecological factors, the decision making relating to priorities with respect to remediation of sites may be influenced by the factors as indicated in the following sections [IAEA – 1998]. Public perception and response to the problem

Differences may exist between the way communities and engineers think about risk, resulting in communications between the two groups sometimes being rather difficult. Experiences have shown hat ‘top-down’ risk communication is unlikely to resolve environmental risk controversies. As a result, risk communication and policy practice have moved towards a two-way dialogue between the ‘community’ and ‘experts’.

Despite for example the tendency to consider widely-reported events to be more likely than they really are, or other biases that have impact on the perception of risk, the ability of the general public to rank frequency of death from hazards is often not unrealistic. However, the perception of the general public diverges from ‘scientific’ risk assessment in that they factor in ‘quality’ of hazard, e.g., thread, familiarity and catastrophic potential. Different forms of death and disease are not feared equally.

Further, the general public’s understanding of a risk should not be confused with the general public’s acceptance of the risk. The level of acceptable risk is a matter of values and opinions. Any evaluation of options should therefore explicitly incorporate underlying values and social factors such as fairness and the balance of benefit and risk. Steps that result in a fair and more voluntary distribution of risk will be helpful. Likely permanence of adverse effect of contamination

The nature of the response to environmental problems at the national level, and eventually at the program or project level, will depend on the nature, the extent and the likely permanence of adverse effects of contamination. This includes the information on radionuclides involved, their distribution affected media, actual or potential exposures of individuals and the general public, and the potential negative effects on the environment. The potential for spread of contamination

An important step should be to assess the potential for spread of exposure from the contamination to humans and the environment.

The diversity of contaminants results in a greater complexity of process and hazards unknown in instances of purely radioactive contamination, such as toxic and corrosive gases or biohazards [IAEA-2006b]. The mixture of contaminants may also result in new or accelerated pathways for migration, for example multiphase flow. There are a number of reasons why sites may first be identified as of potential concern:

  • Known contamination problems, for example, radiation or chemical contamination detected outside controlled process area boundaries, high radiation levels, contamination of surface or groundwater sources or areas of atmospheric deposition;
  • Experience from sites where similar processes and materials were used or with similar histories or geologies, etc.;
  • General review and screening of potential future liabilities, etc.

Contaminants at sites with mixed contamination include radioactive material and toxic substances, heavy metals and certain organic compounds. Other contaminants and hazards that could be present at mixed contaminant sites include nitrates, biohazardous agents, asbestos and materials that pose a physical hazard – i.e. substances that are flammable, corrosive, reactive or explosive.

Typically, the actual quantity of radioactive material at sites with mixed contamination is small relative to the total quantity of hazardous material, and the cumulative risk from the hazardous components often exceeds the total risk from the radioactive component. In addition, many non-radioactive hazardous compounds are more mobile in the environment and have greater potential to contaminate groundwater.

After the seriousness of the problem has been evaluated, the urgency for action can be determined. Situations requiring immediate or urgent action are high priority, as the actual or perceived threat to human health and safety may require a quick response. If the environmental contamination resulted from a past or present practice about which historical information is mostly available, the decision making authority, has more time and flexibility to consider all relevant factors and assess their relative importance. Established radiological and other criteria

The criteria for deciding whether to terminate environmental remedial actions should be clearly stated in the plan. This way an unnecessarily continuation of environmental remediation can be avoided beyond the point at which it is justified and optimized. As an integral part of any successful environmental remediation there should be a clear understanding by the interested parties of the environmental remediation end criteria.

Clean-up or restoration criteria can help in the allocation of resources for clean-up in a cost effective manner. Such criteria are generally derived from radiation protection criteria. International and national organizations and regulatory bodies have established a great variety of limits to restrict or constrain doses that might be received by man. They may, where appropriate, be adopted directly for use in evaluating the need for the restoration of a site.

Restoration criteria can be site specific or generic. Site specific criteria for restoration are typically based on calculated risks to humans or to the environment. This approach allows for the adaptation of clean-up levels to local site conditions. For example, the health risk at a particular site may depend on the combined effect of many factors, such as the radioactive species, its distribution and concentrations, possible pathways, climatic conditions, soil conditions, hydrology, meteorology, and demographics.

Since each site presumably has different conditions, the use of site specific criteria allows the tailoring of restoration criteria to each specific site. In other words, it is possible to assign different clean-up levels while keeping the risk at a uniform level for all sites. However, site specific criteria, typically leading to different restoration levels at different sites (the very reason for its use) may lead to social/political questions of perceived injustice and inequity.

Generic criteria will usually also be based on risk consideration but are not necessarily directly related to the conditions at the site under investigation. Generic criteria are uniform for all sites in a region or country. The major advantage of generic criteria may be their greater political acceptability. As generic criteria do not give rise to different restoration levels, they avoid the appearance of providing different treatment of different population groups. Because of their clarity, generic criteria are also easier to regulate and enforce. The disadvantage of generic criteria is that they may not be universally applicable. By adhering to them, the opportunity of tailoring the expensive clean-up activity to minimum locally required levels can be lost. In some instances, this could dramatically increase the cost over what would be necessary under site specific standards.

In general, the interaction between specific (or local) and generic (or national) regulations, if not harmonized, can significantly increase the cost of and time for the restoration. It is of value to resolve conflicts between these regulations prior to the start of restoration otherwise program / project focus is lost. Negotiations should be initiated to determine the primacy of regulations for each expected situation at the start of the decision making process. It is suggested that communications between local, regional, and national regulators and with the project managers are established and maintained throughout the life of the project. It is also important to consider the full range of regulatory regimes that could impact work at the site. For example, unless allowances are made for local building permits and restrictions (if applicable) there could be significant project delays if facility construction was not carried out in conformance with the local requirements. Potential for trans-boundary effects

The movement of environmental contaminants across national boundaries can have serious consequences for the affected countries.

International agreements exist on the trans-boundary movement of wastes and the disposal of said wastes in international waters. In addition, international standards and conventions exist on waste management practices and radiation protection. An additional area where international factors can be of considerable interest is in the areas of technical or financial assistance. The ability to access technical knowledge from other countries can significantly reduce the challenges to a country with limited experience. Also, the availability of international funding can assist with environmental contamination that threatens other countries. Availability of technological solutions and resources

A wide range of in-situ and ex-situ instruments is available for the detection of radioactivity and hazardous materials to characterize radioactively contaminated sites. In general different radiation detectors will be required to detect different types of radioactivity, e.g. alpha, beta and gamma. EURSSEM gives guidance and a detailed description of instruments available and this is presented in Appendix B (not claiming to be 100% complete).

Most environmental remediation technologies currently available are expensive to implement and may take long periods of time to complete. Continued research is ongoing worldwide to develop new techniques for in-situ and ex-situ remediation. A general list and description of these technologies can be found in Section 4.5 of this document. Care should be taken to evaluate the success or failure of the technologies which have been developed and to compare the site specific characteristics against the test site to determine the viability at a particular site.
Provisions for the different actions in the plan, e.g., establishing stakeholder involvement, historical site assessment, characterization, remediation, post-remediation etc., should be addressed in the remediation plan. As remediation progresses, the plan should be updated to reflect any changes or provisions relating to the conduct and progress of the remediation. Financial capability

The parties who caused the contamination or allowed it to occur should be held responsible for the remediation program and its funding, in accordance with the ‘polluter pays’ principle Principle 4. However, circumstances in many instances may be complex and the total remediation costs may be disproportionately high in comparison with the actions of the organization that caused the contamination. The contamination may, for example, have been caused by changes to exposure pathways that were unforeseen when a discharge authorization was given, or by an accident. In some cases, the economic costs apportioned to an organization would be such that they could lead to its bankruptcy and consequent inability to pay. Adequate funding mechanisms should be foreseen, therefore, and costs may fall wholly or in part on owners, industry, developers, local communities or national governments, as well as on the original polluter [IAEA – 2007a].

Since the apportionment of liabilities may be contentious, particularly when large sums of money are involved, and formally designating a site as requiring intervention may bring an unwelcome depreciation in the value of the surrounding properties, the responsible party should engage with interested parties to negotiate voluntary and cooperative action in preference to the regulatory body initiating enforcement action. Among interested parties should be included: local authorities, owners, tenants, users, potential developers, liability insurance companies, local communities near the site who may benefit from the intervention, those responsible for the source of the pollution and environmental groups.

Regulatory oversight should be maintained and adequate and proportionate funding should be provided, to enable the regulatory body to ensure that any remediation is carried out properly. The government should fund regulatory oversight, or otherwise the regulatory body may fund its regulatory activities through a system of fees chargeable to the project. When urgent action is needed, responsibilities for the remediation should be assigned to a specific organization with adequate technical and human resources to establish and perform the remediation program urgently and to recover the costs at a later time. Lessons learned

The process of designing an environmental remediation plan should take advantage of lessons learned from similar environmental remediation projects that have been completed in the past. These lessons learned may provide both positive and cautionary advice. In effect, information on the failure of a particular method of environmental remediation in certain circumstances may help to narrow the choice of feasible environmental remediation strategies when planning new remedial actions.