As the European Union moves forward with the implementation of the Soil Monitoring and Resilience Law, scientific work is increasingly focused on one of the most challenging aspects of soil protection: determining when metal concentrations in soils become a risk to ecosystems and human health.
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On 20 May 2026, the European Environment Agency and the EU Soil Observatory, hosted by the Joint Research Centre, organized a technical workshop dedicated to the development of Sustainable Target Values (STVs) and Operational Trigger Values (OTVs) for metals in soils. These thresholds will play a central role in the implementation of the new EU soil monitoring framework and in guiding future soil protection measures across Member States.
The workshop brought together policymakers, scientists, and national experts to discuss the scientific basis for establishing harmonized soil thresholds. Representatives from Germany, Austria, and Italy shared national experiences in managing contaminated sites, while discussions also explored how different approaches can be adapted to varying soil conditions across Europe.
A key focus of the event was the presentation of the Soil Threshold Calculator developed by ARCHE Consulting. This tool supports the derivation of ecotoxicological thresholds for metals such as arsenic, cadmium, cobalt, copper, lead, molybdenum, nickel, and zinc. By combining toxicity data, bioavailability models, and site-specific soil characteristics, the calculator can estimate soil concentrations that are protective of plants, soil organisms, birds, and mammals.
One of the main advantages of the tool is its flexibility. Thresholds can be adapted according to different protection objectives, land uses, and soil properties, including pH, organic matter content, clay content, and natural background concentrations. This reflects growing recognition that a single threshold may not be appropriate for all European soils, given the continent’s diverse geological and environmental conditions.
For policymakers, the challenge will be to strike a balance between scientific precision and regulatory practicality. Threshold values must be robust enough to identify potential risks while remaining applicable across different regions and monitoring systems. The workshop highlighted the importance of using harmonized methodologies to ensure comparability of data and consistency in soil assessment across the EU.
The discussions and technical tools presented during the workshop will contribute to European Commission guidance on the implementation of the Soil Monitoring Law, expected by June 2027. As the EU develops its first comprehensive framework for monitoring soil health, defining scientifically sound thresholds for metals will be a crucial step toward protecting soils, ecosystems, food production, and public health in the long term.
More information available at: Arche Consulting, Threshold calculator for metals in soil