Potentially toxic elements pollution in the Musa Estuary: Ecological and human health implications

The Musa Estuary ("Khur-e-Musa") in the northwestern Persian Gulf is a vital coastal ecosystem increasingly impacted by anthropogenic activities, including industrial discharge, maritime operations, and urban runoff. This study assesses the seasonal distribution, bioaccumulation patterns, and ecological and human health risks associated with six potentially toxic elements (Cu, Pb, Cr, Ni, Zn, and Hg) across water, sediment, and selected marine organisms. Seasonal samples were collected and analyzed using flame atomic absorption spectrophotometry. Muscle tissues from four fish species (Platycephalus indicus, Euryglossa orientalis, Sillago sihama, and Chirocentrus nudus) and one shrimp species (Metapenaeus affinis) were examined. Nickel was the most abundant metal across all matrices. Concentrations of Cu in water, Hg in sediment, and Ni in both exceeded established environmental quality guidelines. Among the biota, P. indicus and E. orientalis exhibited the highest bioaccumulation levels (excluding Cu), whereas S. sihama showed the lowest. The bioaccumulation factor for Hg exceeded 1 in most species. Human health risk assessments indicated low estimated daily intake (EDI), target hazard quotient (THQ), and hazard index (HI), suggesting minimal non-carcinogenic risk (HI < 1). However, the carcinogenic risk (TCR) from Ni exposure exceeded acceptable thresholds (TCR > 10^-4) in most species, particularly for adult consumers. These findings highlight nickel pollution as a critical environmental and public health concern in the Musa Estuary. Enhanced regulatory control and continuous monitoring are recommended to mitigate contamination and protect ecosystem and food safety.