Determination of toxic (Pb, Cd) and essential (Zn, Mn) metals in canned tuna fish produced in Iran

BACKGROUND: Metal pollution of waterways directly affects human health and can impact the food chain. Seafood living in polluted water can accumulate trace metals. The purpose of this study was to analyze the toxic metals Pb and Cd and the dietary essential metals Zn and Mn in 120 cans of tuna species from four different brands processed in Iran and purchased in 2012. RESULTS: The mean level of metals for each brands of canned fish obtained in mg/kg were as follows: yellowfin tuna (Pb: 0.19 ± 0.015, Zn: 5.77 ± 4.17, Mn: 0.08 ± 0.07, Cd: 0.15 ± 0.12), Kilka (Pb: 0.95 ± 0.88, Zn: 30.47 ± 29.82, Mn: 1.01 ± 0.73, Cd: 0.07 ± 0.05), Kawakawa (Pb: 0.28 ± 0.23, Zn: 6.77 ± 5.21, Mn: 0.17 ± 0.12, Cd: 0.12 ± 0.09), longtail tuna (Pb: 1.59 ± 1.56, Zn: 7.44 ± 6.11, Mn: 0.04 ± 0.03, Cd: 0.06 ± 0.04). Pb, Zn and Cd levels were generally higher than the FAO/WHO permissible limits (Pb: 0.50 mg/kg, Zn: 50.0 mg/kg and Cd: 0.50 mg/kg) and the European Union acceptable dietary limits. CONCLUSIONS: Based on the United States Environmental Protection Agency health criteria, there is no health risk associated with Mn concentration in the samples analyzed. The limits of detection of the method for Pb, Zn, Mn and Cd in mg/kg were 0.01, 0.5, 0.01 and 0.01, respectively. The result of the one-way analysis of variance suggested significant variations (p < 0.05) in the concentration of the metals in the different types of canned fish with the following being outside of compliance levels.