Toxic metals and aflatoxins occurrence in smoked-dried fish and their health risks assessment

Abstract

This study investigated the microbiological and toxic heavy metals contamination in smoked-dried fish, and evaluates their health risk implications. Fifteen widely consumed fish species were sampled randomly, and their aflatoxins, mercury “Hg,” cadmium “Cd” and lead “Pb” concentrations were evaluated though standard guidelines. The results revealed that fish flesh Hg level ranged from 0.085–0.258 mg/kg, Cd concentration ranged from 0.092–0.204 mg/kg, and Pb level varied from 0.173–0.329 mg/kg; the mean toxic metals level in the freshwater fish tissue was lower, when compared to the levels in the saltwater fish (seafood). Regarding toxic metal toxicity, the average Hg, Cd and Pb estimated daily intake values for children and adult were 0.1200 and 1.63 × 10−5 mg/kg bw/day, 2.13 × 10−4 and 7.57 × 10−5 mg/kg bw/day, and 2.48 × 10−4 and 1.24 × 10−4 mg/kg bw/day respectively. Likewise, children targeted hazard quotients (THQ) values were Hg (0.585), Cd (0.151) and Pb (0.071), while adult THQ values were Hg (0.293), Cd (0.076) and Pb (0.035). Children and adult hazard index (HI) values were 0.949 and 0.404 respectively; while Carcinogenic Risk (CR) values indicated that Cd had higher chances of cancer risks when compared to Pb. Additionally, the aflatoxins level in the fish species ranged from 0.564–9.422 ppb, with the seafood having lower aflatoxins level when compared to the freshwater fish species. Aflatoxins estimated daily intakes (EDI) exposure was 4.81 × 10−3 and 2.41 × 10−3 μg/kg bw/day for the children and adults respectively; while the aflatoxins HI value for children was 7.300 × 10−4, and for adults was 7.293 × 10−4. Health risks assessment of heavy metal accumulation in the fish, for both children and adults portrayed insignificant adverse health effects (THQ < 1), through the oral consumption of the fishes. Aflatoxins level detected in the all fishes was within acceptable limits (10 ppb) as approved by the World Health Organization; however, some of the values for freshwater fishes were above the allowable limit (2 ppb) approved by the European Union. Though, the results depicted a very low risk of toxic metals and aflatoxins poisoning, there is the need for proper evaluation of current fish processing and storage methods to prevent human exposure to toxic metals and aflatoxins introduced through smoked-dried fish consumption.