This phase identifies two different site origins:

• Sites where a Potentially Soil Contaminating Activity (hereinafter PSCA) in accordance with articles 3.1 and 3.2 of RD 9/2005 is being carried out
• Other sites connected with reports of fly-tipping, accidents where dangerous substances have been involved, changes of use of the soil, etc.

The information associated with this phase differs depending on the origin of the site described:

• In the case of the PSCAs, the documentation, of in accordance with RD 9/2005, is the Preliminary Situation Report (PSR).
• For other sites, the documentation is the explanatory report of the events that have taken place, making it possible to evaluate the suspicion of the existence of evidence of pollution.

The documentation presented in this phase and the evaluation of the information content by the administration must make it possible to decide whether there is evidence of soil pollution, that is to say, whether significant pollution has been or is being produced in the soil connected with PSCAs or from other origins.

The existence of evidence of pollution will require amplification of the available information and, therefore, a new investigation stage: Preliminary Evaluation Stage.

This stage corresponds to the preparation of the Preliminary Evaluation Report. There must be a first real approximation to the magnitude of the problem, define the origin and nature of the focus of pollution, the transmission vectors and the subjects to be protected, and define whether emergency actions are necessary.

This stage involves sampling of soils, sediments, residues and/or waters. The results will have to be evaluated and interpreted taking into account the object of protection and the use of the soil or the organisms to be protected.

In this stage, the analytical results of the soil samples must allow a direct comparison of these with the General Reference Levels (hereinafter GRL) established in RD 9/2005.

In this stage too, if the object of protection is human health, it will be necessary to determine whether the concentration of TPH (total petroleum hydrocarbons) exceeds 50 mg/kg and if the object of protection is the ecosystem, whether there is toxicity of in accordance with the bioassays specified in annex IV of RD 9/2005.

The results of this comparison can lead to:

• If the above-mentioned GRLs are not exceeded, the studied soil presents no alteration in its chemical quality that indicates the need to carry out new investigation stages, and so this would be unpolluted soil.
  
  If this depends on the use of the soil, control measures must be established for the case of change of use.
  
  
• If the above-mentioned GRLs are exceeded, the studied soil presents alteration in its chemical quality and, so it will be necessary to carry out a new study phase with a detailed investigation that includes a risk analysis.

The Detailed Evaluation Stage consists in preparing the Detailed Evaluation Report which must make possible a precise identification the focus or foci of pollution, to determine the scope of the pollution, to decide whether the risk is acceptable or unacceptable and, in the latter case, to obtain sufficient information to move on to the following study phase.

In this phase the result of the risk analysis will determine whether:

• The risk is acceptable and then the soil is considered as non-polluted.
  
  If this depends on the use of the soil, control measures must be established for the case of change of use.
  
  
• The risk is unacceptable and, therefore, the soil is considered as polluted.

The consideration of a soil as polluted supposes the obligation to perform the environmental recovery actions for the site. The Recovery Stage of a site is divided basically in three stages:

• The preparation of a Recovery Project, starting from an analysis of the alternatives of recuperation according to technical, financial and environmental criteria.
• The execution of this when the project has been approved. This involves the need to monitor and control the evolution of the environment and, in certain cases, a residual risk analysis.
• The final confirmation of the effectiveness of the actions carried out by means of, if appropriate, a medium or long term monitoring. If the results do not meet the set values, additional proposals for recovery will have to be implemented.