Metal concentrations and toxicity in South African snoek (Thyrsites atun) and yellowtail (Seriola lalandi)

The concentrations of 16 metals were assessed in snoek(Thyrsites atun; n = 20) and yellowtail (Seriola lalandi; n = 37) sampled from the West and South-East coasts of South Africa. Variability was observed at both small (Al, Cr, Hg, Pb, Mn and Cu) and large (As and Cu) spatial scales while inter-specific examination revealed diverse metal concentrations in snoek (Higher levels: Cr, Mn, Co, Hg and Pb) and yellowtail (higher levels: Fe and Cu). Zn, As and Hg were positively correlated with yellowtail size with no such correlations in snoek. Mean concentrations of As (0.61 mg·kg− 1; 0.98 mg·kg− 1), Cd (0.008 mg·kg− 1; 0.004 mg·kg− 1), Hg (0.27 mg·kg− 1; 0.16 mg·kg− 1) and Pb (0.009 mg·kg− 1; 0.005 mg·kg− 1) for snoek and yellowtail respectively were within regulatory guidelines. However, 10% (n = 2) of snoek exceeded Hg maximum allowable limit, suggesting caution and further investigation. Overall, two meals (150 g) per week of snoek or larger yellowtail (12-15 kg) can be safe for human (adult) consumption.