Bibliometric analysis of electronic waste leachates bioaccumulation and ecotoxicological effects in aquatic systems

Amid rapid growth of technological innovation, the world faces an alarming increase in electronic waste (E-waste). The extraction of precious metals from E-waste through acid leaching and open burning releases toxic metals and organic chemical contaminants, posing severe ecological and health issues. Further, the physicochemical properties of E-waste leachates, including their complex chemical composition, various physicochemical properties, and species-specific bioaccumulation of E-waste constituents in aquatic organisms, are also discussed. The physicochemical properties of leachate, such as pH, dissolved organic matter, and metal speciation, strongly influence contaminant mobility and bioavailability in aquatic systems. This review article also discusses the bioaccumulation potential of harmful chemicals released from E-waste, including brominated flame retardants (BFRs), Polychlorinated biphenyls (PCBs), heavy metals, and rare earth elements (REEs). Among Polybrominated diphenylether (PBDEs), PBDE 47 is the most commonly reported congener, indicating its widespread occurrence in contaminated aquatic systems. Evidence indicates that contaminants derived from E-waste leachate bioaccumulate across trophic levels and induce diverse adverse effects like oxidative stress, DNA damage, endocrine disruption, chromosomal aberrations, and tissue damage in species. In aquatic organisms, leachate exposure altered the expression of genes related to reproduction and detoxification, including EcR , DappuHR96, P-gp, CYP314 , CYP360a , and Vtg . Additionally, liquid crystal monomers (LCMs) associated with E-waste are reported to cause retinal impairment and mitochondrial dysfunction in Danio rerio. Thus, the review highlights E-waste leachate as a major vector of contaminant transfer in aquatic ecosystems. Further, directs the need for improved E-waste management, mechanistic toxicological studies, and long-term ecological assessments.