Biofloc systems as a sustainable strategy to minimize heavy metal bioaccumulation in aquaculture

Abstract

Biofloc systems are emerging as a promising alternative to conventional aquaculture due to their potential to improve water quality, enhance fish health, and minimize contaminant risks. This study investigated the role of biofloc technology in reducing heavy metal bioaccumulation and associated health hazards compared with traditional earthen pond systems. Pangasius fish reared in both systems were analyzed for concentrations of Zn, Fe, Cu, Mn, Ni, Cd, and Pb across liver, kidney, gills, and muscle tissues. Results revealed markedly lower accumulation of all metals in biofloc-reared Pangasius, with reductions ranging from 40–80% compared to earthen ponds. Moreover, water and sediment samples of Biofloc ponds also revealed less metal accumulation as compared to earthen ponds. Muscles were the main site of metal deposition, particularly for Zn and Mn, whereas liver and kidney retained higher levels of Fe and Cd in pond-reared fish. Notably, Pb levels in biofloc fish were nearly six times lower than in pond-reared counterparts, and Cd remained well within international safety limits. Health risk assessments confirmed these trends: biofloc Pangasius, exhibited significantly lower non-carcinogenic risk (HI = 1.09E-01) and carcinogenic risk (TCR = 2.91E-04) compared to earthen pond fish (HI = 3.00E-01; TCR = 6.61E-04). Overall, the findings highlight biofloc technology as a sustainable and health-protective aquaculture strategy, capable of mitigating heavy metal contamination, reducing long-term health risks, and supporting safer fish production systems.

Graphical Abstract