Processes driving the degradation of polybrominated diphenyl ethers in terrestrial environment

Polybrominated diphenyl ethers (PBDEs), a class of brominated flame retardants, have gained the attention of many researchers due to their persistence in various environmental matrices. Their usage in numerous consumer products has lent credence to their ability to retard flammable gas formation and brought attention to their ubiquitous occurrence in the environment. PBDEs have been described as endocrine-disrupting chemicals because of their interference with the endocrine system in aquatic and terrestrial animals. In spite of the progress in research over the decades on PBDEs, a full understanding of the environmental behavior and fate of this contaminant is still elusive. Therefore, terrestrial contamination of PBDEs has been evaluated in conjunction with their levels of toxicity, transformation, and transport in various environmental compartments. This review provides a wider perspective of the behavior of PBDEs in the terrestrial environment. Through examining the numerous studies on the environmental contamination of PBDEs, a number of mounting concerns and data gaps have been identified. Numerous methodologies have been discussed including adsorption, catalytic, photocatalytic, electrocatalytic, photo-electrocatalytic, aerobic, and anaerobic degradation. The comparative PBDE degradation analysis suggests that the oxidative degradation pathway is the most appropriate way of wastewater treatment while the role of other soil ingredients on subsurface treatments is still under investigation.