Organ-specific bioaccumulation of trace elements in commercial marine finfish from the South Andaman Islands and associated human health risk assessment

Trace metal contamination in marine ecosystems poses risks to both ecological integrity and human health, yet baseline data from remote oceanic regions remain limited. This study presents the first comprehensive multi-tissue assessment of trace metal bioaccumulation in commercially important marine fishes from the Andaman Islands, India. Concentrations of eleven trace elements (Al, Cd, Cr, Co, Cu, Fe, Pb, Mn, Hg, Ni and Zn) were quantified in gills, liver, intestine and muscle of five fish species ( Cephalopholis sonnerati , Epinephelus bleekeri , Auxis rochei , Rastrelliger kanagurta and Nemipterus japonicus ) collected from major landing centres in South Andaman. Eight metals were consistently detected, while Hg, Cr and Co remained below detection limits across all tissues. Metal accumulation was strongly organ-specific, with liver acting as the primary reservoir for Cu, Fe and Cd, gills reflecting waterborne exposure to Mn and Al, and muscle exhibiting the lowest concentrations. Interspecies variation was limited, indicating broadly similar exposure pathways across trophic groups. Multivariate analyses confirmed clear separation of samples by tissue type rather than species identity. Human health risk assessment based on muscle tissue revealed Estimated Daily Intake and non-carcinogenic risk (HI < 1) values within acceptable limits for all species. However, Total Carcinogenic Risk values for Cd and Pb exceeded the USEPA benchmark, highlighting potential long-term risks for high-frequency consumers. Overall, the Andaman region exhibits a transitional contamination profile dominated by natural lithogenic inputs with emerging anthropogenic signals, underscoring the need for proactive multi-tissue monitoring and context-specific seafood risk communication.