Background: Large quantities of persistent organic pollutants (POPs) and other persistent, bioaccumulative and toxic substances (PBTs) like heavy metals have accumulated mainly over the last century in reservoirs, such as landfills, dump sites, contaminated sites, and mine tailings, as well as in environmental sinks like soils and sediments. Large floods in the past 20 years have demonstrated the mobilisation of POPs/PBTs from these reservoirs, underscoring the limitations of conventional technical safeguard measures like leachate and wastewater treatment or containment systems at landfills.

Results: This study emphasises the need to develop inventories of POPs/PBTs in these reservoirs for the assessment of future risk of increased flooding triggered by climate change and for priority setting of remediation and securing measures. Further, sea-level rise should be included in these assessments as long-term risk for large areas that are likely to be permanently flooded in the coming decades and centuries. In addition, the risk of release of POPs and other PBTs by industries affected by Natural Hazards Triggering Technological Accidents (Natech) should be globally evaluated. The review emphasises the importance of conducting systematic assessments and inventories to understand the risk of these reservoirs for environmental pollution and human exposure. The releases and remobilisation of POPs/PBTs can lead to higher levels in food and drinking water with increased human exposure. In addition to fish, it is crucial to consider livestock grazing in flood plains and other areas affected by floods, and to include them in inventories and risk management.

Conclusion: Based on these assessments, appropriate measures must be developed to eliminate or secure the respective reservoirs, following the precautionary approach. Whilst management measures have been initiated in affected areas (including affected feed/biomass), such as floodplains, there is a need to develop them more systematically. This review advocates for a comprehensive and precautionary approach to address the environmental challenges posed by climate change for POPs and other PBTs reservoirs, with an emphasis on increased flooding and sea-level rise. The substitution of POPs/PBTs in non-essential uses should be implemented to reduce future risks. A synergistic implementation of the Stockholm, Minimata, and Climate Convention can be used as frame for inventories and mitigation.