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

Bosch, Adina C.; O'Neill, Bernadette; Kerwath, Sven E.; Sigge, Gunnar O.; Hoffman, Louwrens C.

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

2017

Bosch, Adina C. | O'Neill, Bernadette | Kerwath, Sven E. | Sigge, Gunnar O. | Hoffman, Louwrens C.

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 (0.61mg·kg−1; 0.98mg·kg−1), Cd (0.008mg·kg−1; 0.004mg·kg−1), Hg (0.27mg·kg−1; 0.16mg·kg−1) and Pb (0.009mg·kg−1; 0.005mg·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 (150g) per week of snoek or larger yellowtail (12–15kg) can be safe for human (adult) consumption.

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