Planning the characterization

The planning of the characterization is based on the previous definition of the objectives and strategies. How detailed the planning is, will depend on the size of the project. In general

there may be a sampling and analysis plan for the surveys of the site. However, other aspects such as quality assurance, data management, health and safety aspects and the project management will need careful attention and should result in a specific plan.

4.2.1. Sampling and analysis plan

Based on the definition of the objectives and strategies for characterization, a Sampling and Analysis Plan is developed which provides the implementor of the characterization with the necessary detail to conduct the characterization investigations in the field and in the laboratory.

This includes what surveys will be done, what samples will be taken, and how they will be collected and measured (e.g. sampling point, time of collection, depth of sampling, and other variables necessary to tie a measurement of a specific sampling location in time and space). In the case of accelerated or expedited characterization, the plan will emphasize the process by which specific sampling activities will be driven on the basis of results. Planning documentation should also define analytical procedures for field and laboratory measurements to determine detection limits, precision, and accuracy.

Sampling points should be located where the contamination is most expected to occur, and only a limited number of constituents should be analyzed. The sampling plan may include the possibility of taking decisions on extending or limiting the survey on the spot, depending on the results of the measurements in the field. A limited number of samples may be defined in the beginning, to verify correlation between survey data and sampling analysis, increasing the number of samples if the correlation is not as good as expected. For complex cases, mathematical techniques may be used to define a statistical distribution of sampling points to give the wanted precision of the distribution of contamination. If pursuing the identification and location of

"hotspots" of contamination, field screening should be used to help initially locate the areas of contamination and the boundaries of contamination. Later phases of investigation will be required to refine the configuration of the contaminant boundaries. Attempting to prove that a site is clean can be difficult and invariably requires very extensive investigation. In this latter case, sampling should always be systematic, and testing for a wide range of contaminants may be involved.

In the development of a sampling and analysis plan, due consideration should be given to the potential spreading of contamination, accessibility of the site and sampling locations, and the pre-sampling approvals that may be required prior to the performance of field work. These considerations are briefly discussed below.

Spreading contamination. Characterization practices should be designed in such way as not to contribute to the further spread of contamination at the site, or off site. This is of particular concern when dealing with radioactive contamination. For example, contamination can be spread through uncontaminated aquifers as a result of poor drilling and well completion practices. Care should be exercised so that onsite workers do not inadvertently carry radioactive contamination off the site through inadequate decontamination processes.

Accessibility. During the planning process it is necessary to consider access logistics, including the ability to physically gain entry to the site, especially for any equipment that is brought in (e.g. drilling rigs, cone penetrometer trucks). It should also be considered whether there are any overhead or underground utilities which may impact the investigation. It may be necessary to limit access to a contaminated area to only specially trained site workers and to allow for a decontamination zone for equipment and personnel.

Jurisdictional concerns. Before initiating field work, it is essential to obtain any approvals necessary to access the area to be characterized. Authorization may be required from governmental or private parties. In addition, it may be necessary to obtain certain permits for digging, drilling, or installing any groundwater wells. A check list of requirements should be prepared to ensure preparedness.

4.2.2. Quality assurance plan

A quality assurance plan (QAP) defines how the integral quality of the environmental data collection process is controlled. The quality objectives are to achieve technically sufficient investigation work, at the right time and at the right price. The QAP will include the description of all relevant responsibilities/functions and a named person for each function. It will also include procedures and working instructions on all operations that may be involved in the final quality of the results. Site operations which should be subject to quality assurance and quality control procedures include monitoring, sample collection and handling and, where appropriate, drilling works and waste disposal. Environmental protection and health and safety aspects should be given highest priority.

For laboratory investigations, the quality assurance plan should define the acceptance limits of measured data in terms of sensitivity, reproducibility, detection limits and accuracy. Quality assurance/quality control protocols are employed to demonstrate the reliability and sample analysis data and compliance with documented sample handling, storage, preparation and test methods.

The quality assurance plan should guarantee that the results are accurate, precise, reproducible, reliable and timely.

4.2.3. Data management plan

As an integral part of the overall characterization plan, the data management plan should define the amount and nature of data to be collected. There will be a strong relation between the quality assurance plan and the data management programme because both aim at the end-product of the characterization data as input for assessment and decisions.

The definition of the databases that will be used in the characterization tasks is also a part of the data management plan. New data will have to be incorporated in the databases as soon as possible to allow quick interpretation and subsequent steering of the characterizations to be done.

Determination of working formats facilitates this action. There can be a different form for each task, but a number of items will be common to all forms.

The further handling of the samples can be documented in the same way. A chain of custody record may be important in many cases. Data collection procedures and working methods should be standardized as much as appropriate for data evaluation and for future use of the data.

The choice of archiving methods for data and samples should be made taking into consideration the future availability of relevant items (storage media, references for mapping coordinates, computer data format and backup system). Good practice in data management includes the identification of a person responsible for data collection. A quick evaluation of incoming data, can avoid long-term gathering of nonrelevant or faulty data. All changes to procedures should be approved by a responsible person and be logged for traceability.

4.2.4. Health and safety plan

The investigation of contaminated sites will involve site workers to close, and possible prolonged, contact with potentially hazardous materials. Therefore, health and safety should be a fundamental consideration in the design and the selection of investigation methods (e.g. use of minimally invasive techniques). Site characterization personnel should be suitably trained and equipped. Planning should prescribe detailed working procedures, including monitoring and dosimetric equipment, protection clothing, identification of access, etc.

4.2.5. Project management plan (cost and schedule)

Once the elements of the characterization planning have been completed, it is necessary to make cost estimates and construct a site characterization time schedule. Estimating costs and time schedules may require revisions in the site characterization strategy. Cost estimates should consider cost of materials, labour, travel, accommodations, and any subcontracting support. The scheduling should anticipate contingencies and decision points. A project manager should be assigned to ensure compliance with the characterization budget and schedule. Selected methodologies to reduce characterization costs are illustrated in Appendix I.

4.3. CHARACTERIZATION TASKS