Gentle Remediation Options (GRO) for Managing Risks and Providing Ecosystem Services at Contaminated Sites

Abstract: Soils are a non-renewable resource and comprise a key component of the world's stock of natural capital. Due to industrialisation, urbanisation and other patterns of unsustainable development, widespread land degradation in the form of contamination, soil sealing, compaction, etc. has impaired the capacity of soils to perform their essential functions and provide humans with vital ecosystem services. Brownfields are typically urban or peri-urban sites that have been affected by the former uses of the site, are or are perceived to be contaminated, and require intervention to bring them back to beneficial use. They also constitute an important and underutilised land and soil resource to provide ecosystem services in urban areas as an element of green infrastructure through the use of nature-based solutions such as gentle remediation options (GRO). Gentle Remediation Options (GRO) are remediation measures involving plants, fungi, bacteria, and soil amendments that can be applied to manage risks at contaminated sites. Several studies and decision-support tools promote the wider range of benefits provided by GRO, including improving soil function to provide ecosystem services, but there is still scepticism regarding GRO implementation. Interviews with a small group of experts have elucidated some of the main possibilities and challenges for GRO implementation in Sweden. As a result, a risk management framework for GRO has been developed to strengthen the decision basis for GRO implementation in practice and address some of the key issues that need to be better communicated, including the various risk mitigation mechanisms, the required risk reduction for an envisioned land use, and the time perspective associated with the risk mitigation mechanisms. The framework is envisioned to be used as a tool for risk communication with stakeholders, decision-makers and regulatory agencies to identify GRO strategies for managing risks at contaminated sites and supporting phytomanagement for sustainable remediation and development. Two case studies are used to demonstrate the application of the risk management framework: Polstjärnegatan and Kolleberga.