Overview
Abolghait and Garbaj measured total mercury by direct mercury analyzer and cadmium and lead by graphite furnace AAS in 20 fresh little tunny and 40 canned light tuna (skipjack and yellowfin) from Tripoli retail markets. Fresh little tunny had the highest mercury, often above 1 mg/kg. Canned yellowfin had the lowest levels of all three metals, while 35% of canned skipjack exceeded the EU lead limit. Arsenic was not measured.
Key numbers
- Total mercury: canned skipjack 0.373 ± 0.249 (0.08 to 0.75), canned yellowfin 0.163 ± 0.122 (0.03 to 0.47), fresh little tunny 1.185 ± 0.968 mg/kg wet weight (Table 3, p. 133).
- Lead: canned skipjack 0.239 ± 0.205 (0.03 to 0.60), canned yellowfin 0.075 ± 0.071 mg/kg wet weight (Table 2, p. 133).
- Cadmium: canned skipjack 0.079 ± 0.058 (maximum 0.19), canned yellowfin 0.027 ± 0.026 mg/kg wet weight (Table 1, p. 132).
Methods (brief)
Mercury was measured directly on homogenized muscle with a DMA-80 (USEPA 7473). For cadmium and lead, about 1 g was microwave-digested and analyzed by Zeeman GFAAS with matrix modifiers. Spiked quality-control samples gave recoveries of 88 ± 15% (cadmium), 127 ± 33% (lead) and 101 ± 2% (mercury).
Evidence Fitness
Twenty samples per group with full descriptive statistics on a wet-weight basis. Mercury data are robust; lead data carry wide recovery uncertainty. Direct evidence for tinned-fish (canned tuna); fresh little tunny results are separate fresh-fish data.