What are they?
Soil is a particularly sensitive medium to contamination. Certain substances and other pollutants can alter its properties and affect the organisms living in it. In addition, pollutants can move from soil to other media, such as groundwater, surface water or air, and reach people through different exposure routes, for example through contact with soil, inhalation of dust or vapours, or consumption of contaminated food and water.
Soil contamination can result from industrial, mining and agricultural activities, waste management, storage of hazardous substances, accidental releases and other human activities.
The European Environment Agency points out that the main soil pollutants include heavy metals and organic pollutants, and also highlights the emergence of emerging contaminants, such as PFAS, certain plasticisers, flame retardants, pharmaceuticals and plastics. Contaminated sites are among the main hotspots for human exposure to soil pollution.
In Spain, the legal concept of contaminated soil refers to soil whose characteristics have been negatively altered by the presence of hazardous chemical components resulting from human activity, at a concentration that poses an unacceptable risk to human health or the environment. The declaration of a soil as contaminated is the responsibility of the autonomous communities.
RISCTOX identifies soil-contaminating substances by taking as a reference the pollutants and generic reference levels established in Annexes V and VI of Royal Decree 9/2005, as well as the criteria established in that regulation for substances not included in those annexes. The Royal Decree establishes different reference values depending on land use and on the protection of human health or ecosystems.
Soil contamination does not necessarily imply occupational exposure. The risk to workers will depend on the presence of the pollutant, its concentration, its properties, the exposure routes and the working conditions.
What can be done?
Identify possible sources of contamination
Workers and their representatives should be able to obtain information about the activities, substances and processes that may cause soil contamination at the workplace.
It is important to request information on:
- Raw materials and hazardous substances used or stored.
- Emissions, discharges and waste generated.
- Storage tanks, pipelines and storage areas.
- Incidents, leaks or spills that may have occurred.
- Measures adopted to prevent soil and groundwater contamination.
- The existence of contaminated or potentially contaminated land at the facility.
Royal Decree 9/2005 establishes a list of activities that may potentially contaminate soil and an information regime concerning these activities.
Include exposure risks in the risk assessment
Where soil contamination exists or there is a possibility of contact with contaminated land, potential worker exposure must be assessed as part of the occupational risk assessment.
Particular attention should be paid to work that may involve direct contact with soil or contaminated materials, such as:
- Excavation and earth-moving work.
- Maintenance or repair of storage tanks and pipelines.
- Spill clean-up operations.
- Handling of waste and materials from contaminated land.
- Soil decontamination and remediation work.
- Activities that may generate dust, aerosols or vapours from the soil.
- Work in confined spaces or areas where vapours from contaminants in the subsurface may accumulate.
Preventive measures should be established according to the characteristics of the pollutants and the exposure routes involved.
Prevent contamination at source
Prevention should prioritise eliminating or reducing contamination at source through:
- Substitution of hazardous substances with less hazardous alternatives where technically feasible.
- Reduction in the use of hazardous substances.
- Improvement of storage and containment systems.
- Prevention and control of leaks and spills.
- Appropriate waste management.
- Preventive maintenance of facilities and equipment.
- Application of best available techniques where applicable.
- Immediate action in response to incidents that may cause contamination.
Participate and access environmental information
Workers and their representatives can contribute to preventing contamination by participating in risk assessments, reporting incidents and deficiencies, and proposing preventive measures.
It is also important to know whether the company's activity is included among activities that may potentially contaminate soil and what information obligations the company has towards the environmental authorities.
Law 7/2022 establishes that operators of activities that may potentially contaminate soil must periodically provide the autonomous community with information that may serve as a basis for declaring contaminated soils. The autonomous communities must prepare inventories of declared contaminated soils and voluntary remediation activities.
Action when soil is contaminated
When soil is declared contaminated, the necessary remediation and recovery measures must be carried out in accordance with the requirements established by the competent authority.
Law 7/2022 establishes, as a general rule, that remediation and recovery measures must be completed within a period not exceeding three years, unless technical reasons associated with the remediation process justify a longer period. Any remaining contamination must be at risk levels that are acceptable for the use of the soil.
Workers involved in decontamination, excavation, treatment or remediation work must be provided with appropriate information and preventive measures based on the pollutants present and the foreseeable exposure routes.
Classification
This section includes the pollutants covered by Annexes V and VI of Royal Decree 9/2005, which establish, respectively:
- Pollutants and generic reference levels for the protection of human health according to land use.
- Pollutants and generic reference levels for the protection of ecosystems.
The Royal Decree also establishes criteria for identifying soils requiring risk assessment and allows other chemical pollutants not included in the annexes to be considered where circumstances justify this.
Soil pollutants can include, among others:
- Metals and metalloids.
- Hydrocarbons and other organic pollutants.
- Solvents and volatile organic compounds.
- Organochlorine compounds.
- Pesticides.
- Other hazardous chemical compounds.
The RISCTOX classification should be understood as a consultation tool and does not replace the specific assessment of the soil or the risk assessment required under applicable legislation.
Legislation
Law 7/2022 of 8 April on waste and contaminated soils for a circular economy.
This is currently the main Spanish legal framework governing contaminated soils. Title VIII establishes, among other matters, potentially soil-contaminating activities, the declaration of contaminated soils, remediation and recovery obligations, and inventories of contaminated soils and voluntary remediation activities. The consolidated text available through the BOE was last updated on 2 April 2025.
This remains the key regulatory instrument for determining potentially soil-contaminating activities and the criteria, pollutants and generic reference levels applicable to the assessment of soil contamination. Its consolidated text incorporates amendments published up to 31 August 2023.
Royal Decree 665/2023 of 18 July.
Among other provisions, this Royal Decree amends Article 5 of Royal Decree 9/2005 concerning groundwater contamination. Where there is evidence or indication of groundwater contamination resulting from soil contamination, the competent water authority must be notified within a period not exceeding one month.
This is the new European framework on soil monitoring and resilience. It establishes a framework for monitoring soil health and provides for risk-based systems to identify, investigate and manage potentially contaminated sites. Member States must transpose the Directive by 17 December 2028.
References
Ministry for the Ecological Transition and the Demographic Challenge (MITECO). Contaminated soils.
Official information on the Spanish legal framework, potentially soil-contaminating activities, information requirements, declaration and remediation of contaminated soils.
European Environment Agency (EEA). Soil pollution and health.
Updated information on soil pollution, contaminated sites, exposure pathways and potential effects on human health. The EEA currently estimates that there are around 2.8 million potentially contaminated sites in the EU and points out that a significant proportion have not yet been registered, characterised, assessed or remediated.
EEA — Soil pollution and health
European Environment Agency (EEA). Europe's environment 2025 — Soil resources.
Recent assessment of the condition of European soils and the main pressures affecting their functions, including pollution. The EEA reports that 62% of European soils show signs of degradation.
EEA — Europe's environment 2025: Soil resources
MITECO. Technical guidance for the application of Royal Decree 9/2005.
Official guidance intended to facilitate the technical application of Royal Decree 9/2005. Although published before the current legislative framework, it remains available as official technical supporting documentation for the application of the Royal Decree. It should not be used to replace or interpret current legislation contrary to its provisions.
MITECO — Technical guidance for the application of Royal Decree 9/2005
Classification sources
Royal Decree 9/2005, Annexes V and VI.
The classification of pollutants in this section is based on the official lists of pollutants and generic reference levels contained in these annexes. The Royal Decree also provides for the consideration of other substances not included in the annexes where the circumstances of the soil require it.
Last content updated::August 2026.