Question 1

What is environmental geotechnics?

Accepted Answer

Environmental geotechnics studies the interaction between soil, groundwater and pollutants to assess risks and ensure the stability and sustainability of the land. It allows the design of safe solutions that minimise environmental impact in construction or industrial projects.

Question 2

What does soil decontamination consist of?

Accepted Answer

Soil decontamination involves identifying, analysing and eliminating or isolating the contaminants present in a field using physical-chemical, biological or confinement techniques. Its objective is to recover the functionality and environmental safety of the affected site.

Question 3

Why can a soil be contaminated?

Accepted Answer

A soil can be contaminated by hydrocarbon leaks, industrial discharges, improper use of chemicals or poor waste management. These agents alter its natural properties and can affect the quality of water and nearby ecosystems.

Question 4

What is a subsurface quality investigation?

Accepted Answer

It is the technical study that allows determining the presence, nature and concentration of possible contaminants in soil and groundwater of a site. Its objective is to assess whether the conditions of the land can be considered altered or contaminated, in accordance with the criteria established in Royal Decree 9/2005, and to serve as a basis for defining the necessary management or remediation measures.

Question 5

Who should conduct a subsurface quality investigation?

Accepted Answer

It must be carried out by those companies or owners of facilities whose activities are considered potentially soil pollutants, according to Royal Decree 9/2005 and Order PRA/1080/2017 . The objective is to check whether the operations carried out have been able to affect the subsoil or groundwater of the site.

Question 6

Where should a subsurface quality investigation be conducted?

Accepted Answer

The characterization of the subsoil should be carried out in all those sites where Potentially Polluting Activities (APCs) of the soil have been or are being developed.

Question 7

Why can a soil be contaminated?

Accepted Answer

A large part of historical and current industrial activities have made and continue to make use of compounds that, once released into the subsoil, can pose a risk to human health and/or ecosystems.

Within the framework of these activities, historically, inadequate waste management and/or environmental accidents have occurred, causing an impact on the soil and/or groundwater. At present, even though there is a much deeper environmental awareness, no facility is exempt from the occurrence of incidents that can potentially affect the quality of the subsoil.

Question 8

What is contaminated soil?

Accepted Answer

According to RD 9/2005 "those whose characteristics have been negatively altered by the presence of chemical components of a dangerous nature from human activity, in such a concentration that it entails an unacceptable risk to human health or the environment".

Question 9

What is subsurface remediation or decontamination?

Accepted Answer

A set of methodologies aimed at the elimination, reduction and/or stabilisation of polluting compounds present in soils and groundwater.

Question 10

What phases are there in soil decontamination?

Accepted Answer

Prior to the selection and design of the restoration technique, the following phases must take place:


	Detailed characterization of the subsoil of the site.
	Carrying out pilot tests of the selected techniques.
	Design and implementation of the most appropriate methodology.
	Follow-up of the remediation process.
	Final verification of remediation.
	Post-remediation monitoring of the subsoil.

Question 11

What subsoil decontamination methodologies are there?

Accepted Answer

There are different methodologies for subsoil remediation, among which the following stand out:


	Excavations: Extraction of contaminated soil for management/recovery as waste.
	In situ chemical oxidation: application of oxidizing agents in the underground environment with the aim of degrading the contaminants present in it.
	Bioremediation: methodology based on the activity of microorganisms present in the underground environment capable of degrading pollutants naturally.
	 Vapour extraction: system for the forced extraction of vapours from the subsoil and the treatment of these.
	 Pumping and treatment: pumping of the affected groundwater and subsequent treatment of the same.
	 Monitored natural attenuation: monitoring of the natural processes that take place in the subsoil that contribute to reducing the concentrations of the pollutants present.

Question 12

What does the quantitative risk analysis study consist of?

Accepted Answer

It is the process of numerical evaluation of various parameters through which the risks that the presence of polluting compounds in the subsoil may pose to human health and ecosystems are studied, analyzed and characterized.

Question 13

When should quantitative risk analysis be carried out?

Accepted Answer

ANNEX IV of RD 9/2005 establishes the criteria for the identification of soils that require risk assessment, whether for human health or ecosystems, affecting those that meet the following conditions:


	That have concentrations of total petroleum hydrocarbons greater than 50 mg/kg.
	There is analytical evidence that the concentration of any of the substances listed in Annex V exceeds the generic reference level corresponding to its current or planned use.

Question 14

What is the EC-SOL Rating?

Accepted Answer

Recognition granted by the Office of Habilitation of Collaborating Entities (OHEC) of the Generalitat de Catalunya that trains an entity and its technical staff to carry out the functions as a Control Entity (CE) in the sectoral field of soil pollution prevention (SOL) in the autonomous community of Catalonia. 

SOCOTEC has this authorization for the fields of action of Research, Quantitative Risk Analysis and Decontamination Projects.

Question 15

What is UNE EN ISO/IEC 17020:2012 Accreditation?

Accepted Answer

According to the National Accreditation Entity (ENAC) "accreditation is the internationally established tool  to generate confidence in the correct execution of conformity assessment activities, allowing to differentiate between bodies that have demonstrated the necessary technical competence to carry them out and that offer reliability in their results from those that have not demonstrated it". 

Currently, SOCOTEC is in the process of obtaining the UNE EN ISO/IEC 17020:2012 Accreditation  for Inspection Entities in the field of soils and associated groundwater and soil gases granted by the national accreditation body.

Question 16

What is soil remediation or soil decontamination?

Accepted Answer

Soil remediation or decontamination is the set of techniques and actions aimed at eliminating, reducing or stabilising the contaminants present in soil and groundwater. Its objective is to restore the safe environmental conditions of the site and ensure that its future use does not pose a risk to human health or ecosystems.

Question 17

What are the times for soil decontamination?

Accepted Answer

Excavations: Extraction of contaminated soil for waste recovery or application of specific treatments to reduce the impact
	In situ chemical oxidation: Introduction of oxidizing agents into the underground environment, mainly in groundwater, to degrade contaminants present in aquifers
	Bioremediation: Enhancement of microorganisms present in the underground environment through nutrients so that they degrade pollutants naturally
	Vapour extraction: System for forced extraction of contaminated vapours from the subsoil, treatment by means of activated carbon filters and return to the environment

Question 18

What does the Human Health Risk Analysis Study consist of?

Accepted Answer

It is a technical assessment that determines the possible exposure of people to contaminants present in soil or groundwater. It allows the quantification of health risks and the definition of corrective or environmental management measures appropriate to the intended use of the land.

Question 19

What does ENAC's EC-SOL accreditation consist of?

Accepted Answer

ENAC's EC-SOL accreditation  certifies the technical competence of entities that carry out investigations and evaluations of potentially contaminated soils. It guarantees that the procedures applied comply with the quality standards and regulatory requirements established by Spanish environmental legislation.

Question 20

Which lands are required to report soil contamination?

Accepted Answer

According to the APC (Potentially Polluting Activity) PRA/1080/2017,  land with the following activities must comply with the regulations: Mining and manufacturing, Chemical industry, Coke plants and oil refining, Prepress services and preparation of supports, Intensive agriculture and livestock, transport and storage of hydrocarbons.

Question 21

When should I do a soil contamination analysis?

Accepted Answer

It must be carried out when there is a change in land use or when the activity carried out is included among the Potentially Polluting Activities (APCs) defined in Order PRA/1080/2017. This analysis makes it possible to verify the environmental status of the site and prevent risks to health or the environment.

Question 22

What role does SOCOTEC play in the management of contaminated soils?

Accepted Answer

SOCOTEC acts as an accredited entity for research, risk analysis and soil decontamination projects, offering comprehensive solutions that guarantee regulatory compliance, environmental safety and technical traceability of the process.

Question 23

What regulations govern soil research and decontamination in Spain?

Accepted Answer

Direct reference to RD 9/2005, Law 7/2022 and Order PRA/1080/2017, key to demonstrating rigour and technical authority.

Question 24

What is the difference between disturbed soil and contaminated soil?

Accepted Answer

It allows explaining the regulatory thresholds between alteration and contamination according to RD 9/2005 and avoids common confusions.

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