Carcinogenic and non-carcinogenic health risks associated with heavy metal exposure in commonly consumed marine fish in Egypt

Abstract

This study aimed to quantify the levels of mercury (Hg), arsenic (As), lead (Pb), and cadmium (Cd) in 250 fish samples, including flathead grey mullet, sardine, and mackerel, collected from local fish markets in Mansoura, Egypt, on ten occasions from August 2023 to March 2024. Unlike previous studies that have primarily focused on metal concentrations, this study assessed both carcinogenic and non-carcinogenic health risks among the general population (57.09 g/day) and high-fish consumers (200 g/day). Metal concentrations were determined using atomic absorption spectrophotometry, with method accuracy validated using certified reference materials (CRMs), yielding recoveries of 95.5–100.6%. The average concentrations of Hg, As, Pb, and Cd (µg/g wet weight) were 0.313, 2.13, 0.194, and 0.018 in flathead grey mullet (As > Hg > Pb > Cd); 0.131, 1.65, 0.472, and 0.021 in sardine (As > Pb > Hg > Cd); and 0.196, 0.98, 0.370, and 0.025 in mackerel (As > Pb > Hg > Cd), respectively. Hg and As concentrations were significantly higher in flathead grey mullet, whereas Pb concentration was highest in sardine and Cd concentration was highest in mackerel. Based on the Maximum Permissible Limits (MPLs) set by the Food and Agriculture Organization (FAO), Egyptian Organization for Standardization and Quality (EOS), and Food Standards Australia New Zealand (FSANZ), the proportion of samples exceeding these limits ranged from 9 to 20% for Hg, 22–56% for As, and 20–58% for Pb. For the general population, only the estimated daily intake (EDI) of Hg in flathead grey mullet was above the Provisional Tolerable Daily Intakes (PTDIs), while EDI of most metals exceeded safety thresholds in high fish consumers. Target Hazard Quotient (THQ) for Hg and As exceeded 1.0, while TTHQ values for flathead grey mullet, sardine, and mackerel were 8.4, 5.7, and 4.35 for the general population and 29.43, 19.84, and 15.26 for high-fish consumers, respectively, indicating potential non-carcinogenic health risks. Furthermore, cancer risk (CR) for As ranged from 1.20E−03 to 9.14E−03, exceeding the acceptable safety threshold of 1.0E−04, whereas Pb and Cd risks remained within safe limits. The relatively high metal concentrations may reflect anthropogenic pollution and other environmental inputs affecting the aquatic ecosystem, highlighting the need for regular monitoring and control of pollution sources to reduce contamination and protect public health.