Trace elements in freshwater killifish, Aphanius stoliczkanus, from Oman: A food safety issue

Freshwater killifish, Aphanius stoliczkanus, were collected from industrial and non-industrial areas in Oman to assess trace element levels in muscle and liver tissues and estimate potential human health risks using the Estimated Daily Intake (EDI) and Target Hazard Quotient (THQ). Samples were obtained from Al Amarart, Al Khawd, and Surur and analyzed using Atomic Absorption Spectroscopy. Fish from Al Amarart exhibited significantly higher concentrations of toxic elements, particularly arsenic (As), cadmium (Cd), and lead (Pb), suggesting a strong influence of industrial activities. In contrast, trace element concentrations in fish from Al Khawd and Surur were lower, reflecting reduced anthropogenic inputs. In almost all sites, most metals accumulated at higher levels in the liver than in muscle, indicating increased bioavailability for essential elements or detoxifying function for toxic metals. Despite the variation in contamination levels, THQ values for all elements remained below the threshold of concern (THQ < 1), suggesting that individual exposure through fish consumption does not pose immediate health risks. Similarly, the calculated cancer risk (CR) for As was within acceptable limits at all sites. However, while the direct risk from A. stoliczkanus consumption appears low, potential cumulative effects from multiple dietary and environmental sources should not be overlooked. Bioaccumulation through trophic transfer and exposure from water and other food sources may lead to long-term health concerns. Overall, these findings highlight A. stoliczkanus as a valuable bioindicator of trace element contamination in industrial regions. Continued environmental monitoring and stricter pollution control measures are recommended to mitigate contamination sources and ensure long-term food safety. Further studies should explore temporal trends and additional toxicity biomarkers to provide a more comprehensive understanding of ecological and human health risks.