Daish, Minen Raheem; Daish, Minen Raheem; Hussein, Haider Mashkoor

doi:10.29350/qjps.2026.171437.1108

"Assessing the Food Safety of Imported Fish via Spectral Quantification of Lead, Cadmium, Zinc, and Nickel: A Comparative Analysis of Canned Tuna, Sardines, and Frozen Fish "

10.29350/qjps.2026.171437.1108

Volume 31, Special
Summer 2026

Document Type : IAAQC Conference

Authors

Minen Raheem Daish

Haider Mashkoor Hussein

Department of Environmental, College of Science, University of Al-Qadisiyah, Al- Qadisiyah, Iraq

Abstract

Background. Imported canned and frozen fish are becoming an increasingly important source of dietary protein in Iraq, yet recent monitoring data on heavy-metal residues in these products remain limited. Species-specific bioaccumulation, processing conditions, and source-area differences may increase dietary exposure to Pb and Cd.

Objective.This study measured Pb, Cd, Zn, and Ni in canned tuna, canned sardines, and imported frozen fish sold in Iraq, assessed compliance with international maximum residue limits (MRLs), and examined inter-element relationships suggesting common contamination sources.

Methods. A comparative cross-sectional design included 39 products: 25 canned tuna, 7 canned sardines, and 7 frozen fish, analysed in triplicate (n = 117). Samples were oven-dried, digested using HNO₃, HClO₄, and H₂SO₄, and analysed by flame atomic absorption spectroscopy. Shapiro–Wilk and Levene tests assessed assumptions, Kruskal–Wallis with post-hoc comparisons assessed group differences, Pearson correlation evaluated inter-element relationships, and η² estimated effect size.

Results. Frozen fish showed higher Pb (93.70 ± 25.38 µg/kg) and Cd (4.29 ± 1.25 µg/kg) than canned tuna and sardines. Kruskal–Wallis tests were significant for all metals (p < 0.001), with η² ranging from 0.57 for Zn to 0.89 for Pb. The highest Pb level was detected in Iranian trout (131.20 µg/kg), while the highest Zn level occurred in Chinese sardines (197.10 µg/kg). No sample exceeded Codex MRLs.

Conclusion. Although all products complied with MRLs, imported frozen fish showed substantially higher Pb and Cd levels, supporting targeted import surveillance.

Keywords

atomic absorption spectroscopy

canned fish

frozen fish

food safety

Codex Alimentarius