Polybrominated diphenyl ethers (PBDEs) contamination across environmental compartments in Europe

PBDEs are persistent organic pollutants used as flame retardants in consumer products. Despite regulatory restrictions in Europe, their persistence, bioaccumulation, and long-range transport remain environmental concerns. This systematic review assessed the occurrence, distribution, and congener-specific patterns of PBDEs across European environmental compartments and examined the implications of legacy sources and regulatory frameworks. The review followed PRISMA guidelines and was registered in PROSPERO (CRD420251207298). Peer-reviewed studies were retrieved from Ovid, Scopus, and Web of Science up to November 2025. In total, 181 studies met the inclusion criteria. Data were synthesized across air, water, sediments, soils, snow/firn, and sludge. Study quality and risk of bias were assessed using the SURE checklist. PBDEs were widely detected across Europe in both impacted and remote environments, with distributions strongly dependent on matrix type. Water generally showed lower, more transient concentrations, whereas sediments, sludge, and some soils acted as major reservoirs. BDE-209 dominated particle-rich matrices, including sediments, wastewater-related systems, and deposition, while lower-brominated congeners such as BDE-47 and BDE-99 were more prominent in air and soils. The highest burdens were typically linked to urban, industrial, wastewater-affected, and waste-handling environments, whereas alpine, Arctic, and background sites showed lower but measurable contamination. Several studies reported declining trends, especially in air and soil, but continued detection reflected persistence in legacy materials, recycled products, contaminated reservoirs, and waste streams. PBDEs remain environmentally relevant across Europe despite regulatory controls. Their persistence across compartments and continued release from legacy sources highlight the need for harmonized multi-matrix monitoring, improved QA/QC reporting, and greater attention to BDE-209, transformation products, and replacement flame retardants.