Overview
Hussien and colleagues digested the contents of canned tuna, salmon and sardine cans (fish plus brine or oil) in potassium hydroxide, identified microplastics on the filters by FTIR, and analyzed the filtrate by ICP-MS for 20 elements. Aluminum, selenium, zinc, antimony and arsenic were found; cadmium, lead, chromium, nickel and nine other elements were printed as 0.00. Mercury was not analyzed. All element values are concentrations in the digest filtrate, not in fish.
Key numbers
- Aluminum: 0.8268 ± 0.00 ppm (sardine, Indonesia) to 18.5701 ± 0.05 ppm (sardine, Morocco) in filtrate (Table 2, p. 834).
- Arsenic: 0.4087 ± 0.001 ppm in filtrate for tuna from Italy only; 0.00 in the other six products (Table 2, p. 834).
- Antimony: 1.8476 ± 0.001 (tuna, Italy), 1.7192 ± 0.001 (salmon, Thailand), 0.1277 ± 0.00 ppm (sardine, Morocco) in filtrate (Table 2, p. 834).
- Cadmium and lead: 0.00 in every product (Table 2, p. 834).
Methods (brief)
About 40 g of can contents per brand were digested in 10% potassium hydroxide at 40 °C for 72 hours, filtered, and the filtrate analyzed by ICP-MS. Triplicate cans per brand were pooled. No detection limits, reference materials or recoveries are reported.
Evidence Fitness
Seven products, one brand each, with an alkaline digestion that is not a validated total-element method. Values are reported per filtrate, so they cannot be compared with tissue limits, though the paper does so. Zeros carry no detection limit. Treat as weak, semi-quantitative evidence for tinned-fish; the extraction flags every value.