Arsenic crisis: unravelling toxicity, microbial solutions, and green bioremediation

Arsenic poisoning in water and soil poses a significant global health and environmental concern, impacting millions with risks of cancer, cardiovascular disorders, and arsenicosis, especially in areas such as South Asia, Southeast Asia, and Latin America. Traditional treatment approaches, such as coagulation, precipitation, filtration, ion exchange, and membrane processes, frequently face drawbacks such as high cost, sludge generation, ion interference, low regeneration, and disposal issues. Recent advancements highlight the potential of microbial bioremediation strategies, including biosorption, bioaccumulation, oxidation, reduction, methylation, and volatilization as promising alternatives, with extracellular polymeric substances (EPS) emerging as a pivotal yet underexplored factor. EPS, secreted by bacteria, fungi, and cyanobacteria, emerging as a critical yet insufficiently studied component. EPS facilitate arsenic sequestration through functional groups and biofilm matrices. This study critically reviews arsenic toxicity, its geographical distribution, and microbial remediation techniques, emphasizing EPS-driven bioremediation as a sustainable approach. It further identifies gaps in molecular insights, microbial diversity, and field applicability, while proposing future innovations through genetic engineering, nanobiotechnology, and pilot-scale demonstrations to ensure safe water access and long-term environmental resilience.