| 02 Sep 2026
The impacts of remediation techniques on soil functions: a review
Abstract. Soil contamination is a major driver of soil degradation in Europe, and remediation practices are increasingly expected to support not only risk reduction but also the recovery of soil health and ecosystem services. In line with the European Soil Monitoring and Resilience Directive, this review evaluates how commonly applied remediation techniques impact key soil functions that underpin soil health. A structured narrative review of the literature was conducted to assess the impacts of conventional (physical and chemical) and low‑impact (biological and nature‑based) remediation techniques on six aggregated soil functions: organic matter storage and transformation, water regulation, nutrient cycling, contaminant retention and degradation, physical stability, and habitat provision. The analysis shows that conventional remediation techniques such as thermal treatment, soil washing, in‑situ chemical oxidation/reduction, and stabilization/solidification frequently achieve effective contaminant removal but often cause substantial and sometimes irreversible degradation of soil structure, organic matter, microbial activity, and habitat quality. In contrast, low‑impact remediation approaches, including bioremediation, phytoremediation, monitored natural attenuation, and immobilization with organic or selected inorganic amendments tend to preserve or enhance soil functions, although typically at slower contaminant removal rates and with strong site specificity. The review highlights critical knowledge gaps, particularly regarding limited information on specific remediation techniques and impacts on soil fauna, the limited availability of quantitative thresholds for when a soil can be considered healthy or unhealthy for performing various functions, and limited soil health assessments in urban and industrial context. Hybrid and adaptive remediation strategies that combine risk reduction with rehabilitation measures are identified as key to balancing risk reduction and soil functionality while also planning for refunctionalization at the onset as part of the soil health trajectory. Overall, embedding soil health as a central management objective is essential for sustainable contaminated land management aligned with European policy goals.
This is a very interesting, relevant and timely review addressing the impacts of different soil remediation technologies on soil functioning and health. The topic is highly relevant, and the manuscript has the potential to make a valuable contribution. However, I believe that the text still needs some polishing. In particular, some sentences are overly long and could be reformulated to improve readability and facilitate understanding. I also recommend ensuring greater consistency in the terminology and concepts used throughout the manuscript (or clearly distinguishing between concepts where they are not equivalent).
I also think that the methodology used to conduct the review should be described in greater detail. In my opinion, the manuscript would benefit substantially from a more quantitative approach. Apart from that, I would recommend incorporating the reduction in contaminant concentrations into the comparison. Since the manuscript argues that remediation technologies should aim to achieve both risk reduction through contaminant removal and the maintenance or improvement of soil health and functioning, these two dimensions should ideally be evaluated together.
The Results section is currently very long, with an extensive description of each technology and its individual impacts. I believe the manuscript would benefit from synthesising this information more effectively and focusing on the main patterns emerging across technologies. Finally, it is positive that the manuscript concludes by identifying knowledge gaps and discussing soil refunctionalisation and the need to balance risk reduction with the preservation or recovery of soil functionality.
Specific comments:
Please reconsider the terminology used to distinguish the two main types of remediation technologies. The manuscript currently distinguishes between conventional technologies (physical and chemical) and low-impact technologies (biological and nature-based). However, amendments are included in the latter category despite being chemical interventions. What terminology is currently most widely used in the literature? Gentle remediation options (GROs) could potentially be considered as an alternative term for the second group.
L30: Why not use “land use” instead of “context”?
L42: I believe “unhealthy” is more appropriate than “healthy” in this sentence. Please check and correct.
L45 and throughout: Please ensure consistency in the terminology used for the different concepts. The manuscript refers to soil quality indicators, soil descriptors, indicators, proxy indicators, etc. These terms should either be used consistently or their differences should be clearly defined.
Some sentences are overly long and would benefit from being reformulated to improve readability (e.g., L57-61 and L108-130).
L107: Please use “SML” instead of “Soil Directive”.
L114: Please spell out the abbreviation at its first occurrence and use the abbreviation thereafter (e.g., SOC).
L126: “Effects on macrofauna (earthworms)”: Does this refer specifically to earthworm abundance? Please clarify.
Similarly, the parameters included in Tables S2 and S3 should be described more clearly. For example, it is unclear what methodology or measurement is represented by “Functional diversity/genes” or what MSIR refers to. There is also a question mark in Table S3 whose meaning is unclear and should be checked.
L136: How do you determine whether a study is representative if the review is simultaneously described as non-exhaustive? Please clarify the criteria used.
L145: Please specify the starting year of the literature search.
Table 1: The manuscript does not explain how it was determined which category a given result belongs to.
As mentioned above, I believe the robustness and impact of the manuscript would be substantially enhanced by performing a quantitative estimation of the effects of each remediation treatment on soil functions, ideally by comparing the response with the control treatment within each individual study. This would provide a more objective assessment of the magnitude and direction of the effects across remediation technologies.
Table 2: It would be useful to report the number of studies considered for each soil function and remediation technology. It is also unclear how the mean value reported for each soil function was calculated.
As mentioned above, it would also be highly valuable to include the mean reduction in contaminant concentrations achieved by each technology.
Figure 1: I believe it is important that pollutants are not transferred to the final products of biofuel production. See, for example, Tripathi et al. (2016), https://doi.org/10.1016/j.rser.2015.12.116. Please revise the figure accordingly.