de Lima et al. 2021 — Metals and metalloids in canned tuna and sardines sold in Brazil
This data article (published in Data in Brief, a peer-reviewed data repository journal) reports ICP-OES measurements of 13 elements (Al, As, Ba, Ca, Cd, Co, Cr, Cu, Fe, Ni, Pb, Se, Zn) in canned tuna and canned sardines from Brazilian supermarkets in Campo Grande, Mato Grosso do Sul. The study covered four tuna brands in four packaging formats (natural grated, oil grated, solid natural, solid in oil) and five sardine brands in two sauce types (oil and tomato sauce), measured by microwave-assisted acid digestion followed by ICP-OES. The key findings are that Cd, Co, Cr, Ni, and Pb were below LOD in almost all canned tuna samples, while As (total, reported without speciation) exceeded FAO/WHO permissible limits (PI > 1) across all tuna variants; in canned sardines, Cr and Ni also showed PI > 1 in several samples. Health Risk Index (HRI) calculations for canned tuna showed concern for Al, As, Ba, and Ca at the portion-level; for sardines, Cr, Ni, and As HRI values exceeded 1 in some samples. Raw data are available on Mendeley Data (10.17632/zf95gwjjmk.1).
Important speciation note: Arsenic in this paper is reported as total arsenic (tAs) measured by ICP-OES, not speciated into iAs vs organic species. In canned fish, total arsenic is dominated by organic forms (arsenobetaine, DMA) and the health-relevant iAs fraction is typically a small proportion. The PI > 1 finding for As in all tuna samples uses an FAO/WHO permissible limit of 0.5 µg/g total arsenic for fish fillet; this limit applies to total arsenic and does not distinguish iAs. The HRI calculation likewise uses total arsenic with the USEPA reference dose for inorganic arsenic (0.0003 mg/kg/day), which overestimates risk from organic arsenic forms. These risk assessment calculations should be interpreted with caution.
Key numbers
Canned tuna — arsenic (tAs, mg/kg, mean ± SD of triplicate):
- Natural grated tuna, brands G/C/O/P: 1.943 ± 0.088; 1.612 ± 0.054; 1.642 ± 0.034; 1.473 ± 0.084 mg/kg
- Oil grated tuna, brands G/C/O/P: 1.783 ± 0.011; 1.693 ± 0.098; 1.379 ± 0.049; 1.610 ± 0.012 mg/kg
- Solid natural tuna, brands G/C/O/P: 1.330 ± 0.018; 1.538 ± 0.089; 1.278 ± 0.025; 1.671 ± 0.048 mg/kg
- Solid tuna in oil, brands G/C/O/P: 1.875 ± 0.044; 1.684 ± 0.007; 1.756 ± 0.111; 1.864 ± 0.153 mg/kg
- All tuna tAs values range approximately 1.3–1.9 mg/kg; all exceed the FAO/WHO fish fillet permissible limit of 0.5 µg/g (PI > 1 across the board, PI values 2.5–3.8)
Canned sardines — arsenic (tAs, mg/kg):
- Sardines in oil, brands G/C/O/P/Pa: 3.224 ± 0.108; 3.053 ± 0.347; 3.069 ± 0.224; 4.493 ± 0.387; 3.112 ± 0.322 mg/kg
- Sardines in tomato sauce, brands G/C/O/P/Pa: 3.790 ± 0.025; 3.839 ± 0.045; 2.676 ± 1.044; 3.345 ± 0.169; 2.467 ± 0.266 mg/kg
- Sardine tAs range approximately 2.5–4.5 mg/kg; PI 4.9–9.0, highest As exceedance in the dataset
Cadmium (Cd): Below LOD in all canned tuna and all canned sardines samples Lead (Pb): Below LOD in all canned tuna; trace detections in sardines (0.005–0.011 mg/kg), all well below limits Nickel (Ni): Below LOD in all canned tuna; below LOD in most sardines Chromium (Cr): Below LOD in all canned tuna; detected in sardines: 0.007–0.110 mg/kg; PI > 1 in some sardine samples Aluminum (Al): Detected in natural grated and solid tuna: 10.3–47.3 mg/kg; PI > 1 in solid natural tuna variants; below LOD in many oil-format tuna and in most sardines
LOD values (ICP-OES, for NGT/SNT samples): Al 0.097 mg/L; As 0.0063 mg/L; Cd 0.0010 mg/L; Cr 0.0015 mg/L; Ni 0.0025 mg/L; Pb 0.010 mg/L; Se 0.011 mg/L.
Methods (brief)
Canned tuna (4 brands, 4 types: natural grated/oil grated/solid natural/solid in oil; three cans each) and sardines (5 brands, 2 types: oil/tomato sauce; two cans each) from Campo Grande supermarkets. Oil or sauce drained; meat ground in stainless steel blender. Microwave-assisted digestion: 400 mg sample, 1.0 mL HNO3 (65%), 3.0 mL high-purity water, 1.0 mL H2O2 (35%), Speedwave four (Berghof). ICP-OES (iCAP 6300 Duo, Thermo Fisher Scientific) for 13 analytes. Spike-and-recovery 95–117% for all elements. Calibration curves 0.005–2.0 ppm, R² 0.991–0.999. Results reported as mg/kg (fresh weight of drained meat). Raw data on Mendeley: DOI 10.17632/zf95gwjjmk.1.
Implications
Certification: This paper is useful for establishing that Cd and Pb are effectively below detection in commercially processed canned tuna from Brazil; the As values are total arsenic and reflect organic arsenic dominance in marine fish — they should not be used for iAs risk assessment without speciation data. The Al signal in solid tuna variants deserves attention for HMT&C if the program considers Al as a monitored analyte.
Courses: Illustrates the critical importance of As speciation: reporting tAs PI > 1 for canned fish against a limit designed for total arsenic without distinguishing arsenobetaine from iAs produces misleading contamination signals. The sardine As data (PI up to 9.0 for total As) would be alarming if inorganic; in practice most is organic arsenobetaine.
App: tAs values in canned tuna (Brazil): ~1.3–1.9 mg/kg; canned sardines: ~2.5–4.5 mg/kg. These are total arsenic and likely dominated by arsenobetaine. Do not substitute for iAs profile.