Microplastics, heavy metals, antibiotics, and antibiotic resistance genes in recirculating aquaculture systems

The growing concerns over food safety and pollutants, especially emerging contaminants like microplastics (MPs) and antibiotic resistance genes (ARGs) in aquatic environments, have attracted considerable research attention. This paper provides a comprehensive review of MPs, heavy metals, antibiotics, and ARGs within Recirculating Aquaculture Systems (RAS), exploring their occurrence, characteristics, sources, impacts, removal strategies, and interactions. MPs are found in varying concentrations in RAS, especially in fish tissues, raising concerns about fish health. Heavy metals in RAS, originating from feed, pipe corrosion, and make-up water, accumulate, posing risks to fish and necessitating stringent control measures. Antibiotics persist in RAS water and sediment, contributing to ARGs, posing a threat to both fish and human health. Research gaps persist in the removal of MPs, efficient heavy metals control, and addressing antibiotics and ARGs pollution in RAS. Controlling MPs is crucial due to their role as ideal carriers, potential reservoirs, and hotspots for other pollutants, emphasizing the need for comprehensive approaches to mitigate environmental and health risks. The field encounters notable challenges but presents promising avenues for future research in RAS.