The Updated version of SF Box: A method for soil quality classification as a basis for applicable site-specific environmental risk assessment of contaminated soils

Report, 2019

This technical note summarises major changes in the updated version of SF Box, which is part of the SCORE – the Multi-Criteria Decision Analysis method for decision support in soil remediation projects. SCORE stands for the Sustainable Choice Of REmediation and SF Box stands for Soil Function toolBox. The SF Box tool has been developed for soil function assessment to complement environmental risk assessments, in order to increase awareness of decision-makers for inherent soil qualities other than concentration of contaminants and their availability/mobility, which are critical for proper soil functioning, e.g. availability of water and nutrients for soil organisms, but often ignored in remediation projects (driven by protection of the soil environment with ambition to recover ecosystem functions) in Sweden. The tool is based on a scoring method using soil quality indicators (SQIs) for assessing (I) the soil’s capacity to perform its functions in its own reference state of being ‘clean’, i.e. “what can this soil do and can it perform its functions well, assuming that it is free of contaminants?”, and (II) the effects of the remedial actions themselves on soil functions, i.e. “can the remediated soil continue to perform these functions well?”. The earlier version of SF Box addresses the soil functions associated with Primary Production. By (i) taking into consideration the perspectives of soil microbiology, soil fauna and vegetation, (ii) slightly modifying the set of SQIs (consisting of soil texture, content of coarse material, organic carbon/matter, available water, C/N ratio, pH and available phosphorus), and (iii) revisiting the curves for scoring of soil performances on each SQI, the SF Box tool has been updated to assess the soils’ capacity to function as a basis for Life and Habitat of flora and fauna. This updated version is therefore aimed to provide an improved basis for site-specific environmental risk assessment by means of (1) differentiating between the effects of contamination on soil biota and the effects of soil capability to function as a host to these species in its own reference state free from contaminants, and (2) classification of the soils (usually characterized by heterogeneity at contaminated sites) in accordance with their overall performance on the selected SQIs for further analysis of ecotoxicological risks in each soil class.