Widespread pollution from industrial activities has driven land degradation with detrimental human health effects, especially in urban areas. Remediation and redevelopment of the estimated 5 million brownfield sites globally is needed to support the sustainable transition and increase urban ecosystem services, but many traditional strategies are often environmentally harmful. In this Review, we outline sustainable remediation strategies for the clean-up of contaminated soil and groundwater at brownfield sites. Conventional remediation strategies, such as dig and haul, or pump and treat, ignore secondary environmental burdens and socioeconomic impacts; over their life cycle, some strategies are more detrimental than taking no action. Sustainable remediation technologies, such as sustainable immobilization, low-impact bioremediation, new forms of in-situ chemical treatment and innovative passive barriers, can substantially reduce the environmental footprint of remediation and maximize overall net benefits. Compared with traditional methods, they can typically reduce the life-cycle greenhouse gas emissions by ~50-80%. Integrating remediation with redevelopment through nature-based solutions and sustainable energy systems could further increase the socioeconomic benefit, while providing carbon sequestration or green energy. The long-term resilience of these systems still needs to be understood, and ethics and equality must be quantified, to ensure that these systems are robust and just.
Nature Reviews Earth & Environment
Review articleoften hindered by high costs, cumbersome administrative processes and uncertain remediation performance 12 . Sustainable remediation has the potential to accelerate BRR 13 through accounting for three factors: adverse life-cycle impacts of traditional remediation, institutional pressures exerted by new industrial norms, and stakeholder demand for sustainable practices 13 . Yet there are also concerns that businesses will use this concept for 'green washing' (claiming a remediation project or technology is sustainable, without robust evidence 14 ) or to reduce project costs by undertaking less remediation 15 . Thus, it is vital to better understand the holistic impacts of remediation and redevelopment to support the implementation of sustainable practices.In this Review, we outline sustainable strategies for BRR. We begin with a discussion of the primary, secondary and tertiary impacts of traditional practices over the life cycle of remediation. Then, we summarize promising sustainable strategies, namely, innovative in-situ soil and groundwater remediation technologies and strategies that integrate remediation with redevelopment. We end by identifying challenges and future research directions.
Life-cycle impactsTraditional brownfield remediation was long considered inherently sustainable because it removes toxic chemicals from the environment, frees up contaminated land for reuse and reduces urban sprawl. However, holistic sustainability assessments and life-based approaches have exposed...