Heavy metals bioaccumulation and critical risk analysis in the endemic crustacean Callianassa kraussi stebbing and edible fish Pomadasys commersonnii from Durban Harbour, South Africa

Heavy metal contamination in aquatic ecosystems poses significant risks to marine life and human health. This study assessed the bioaccumulation of heavy metals (Al, As, Cr, Cu, Mn, Ni, Pb, Zn) in Southern African sandprawn (Callianassa kraussi, n = 18) and spotted grunter (Pomadasys commersonnii, n = 25) from the urbanized Durban Harbour, South Africa, using Inductively Coupled Plasma Optical Emission Spectroscopy (ICP-OES). Health risks to regular consumers of P. commersonnii were also assessed. C. kraussi exhibited significantly higher metals concentrations (2.8 +/- 1.1 - 318 +/- 137 mg/kg (dw)) than P. commersonnii (1.4 +/- 1.0 - 24 +/- 10 mg/kg (dw)), with a similar to 7-fold higher metal pollution index linked to industrial, agricultural, and vehicular pollution. In C. kraussi, As, Cr, Cu, Pb, and Zn exceeded WHO/FAO limits, while in P. commersonnii, only As and Pb surpassed permissible levels. Health risk analysis identified non-carcinogenic risks from As (HQ = 1.43-1.68) and significant cancer risks from As, Ni, and Pb, particularly for children. Total cancer risk (CRtot) for adults (1.03 x 10(-3)) and children (1.2 x 10(-3)) exceeded the threshold of 10(-3), highlighting carcinogenic risk from consuming P. commersonnii. The findings underscore the need for ongoing monitoring to mitigate food safety risks and protect Durban Harbour's ecosystem.