Integrated Risk Analysis of Microbial and Chemical Contaminants in Smoked Fish from Warri Markets, Nigeria
Tega Lee-Ann Ataikiru *
Department of Environmental Management & Toxicology, Federal University of Petroleum Resources, Effurun, Delta State, Nigeria.
Gabriel Tejiri Obahor
Integrated Institute of Environment and Development, Federal University of Petroleum Resources, Effurun, Delta State, Nigeria.
*Author to whom correspondence should be addressed.
Abstract
Smoked fish remains one of the most popular commodities due to its long shelf life, pleasant taste, and widespread availability among both urban and rural populations. In the Niger Delta region where fishes are smoked traditional, there are significant concerns about microbial contamination and toxicological safety regarding this practice. This study investigated the degree of microbial contamination and toxicological risk associated with the presence of polycyclic aromatic hydrocarbons (PAHS) and heavy metals (HMs) in smoked fish from five major markets in Warri, Delta State. The microbial load, PAHS, and HMs content in forty (40) Scomber scombus smoked fish (Atlantic Mackerel) obtained from Effurun, Polokor, Igbudu, Okere, and Ogbe-Ijoh markets using standard microbiological methods, gas chromatography-mass spectrometry, and atomic absorption spectrophotometry. A human health assessment was conducted according to the standards of the United States Environmental Protection Agency and the World Health Organisation. High bacterial contaminations, especially Salmonella spp., Escherichia coli, Listeria monocytogenes, Vibrio spp., and Shigella spp., were observed with E. coli having the predominant counts from the smoked fishes in the five markets; the highest potential E. coli count was in Igbudu (2.61 × 10-7 CFU/g) and Salmonella was 9.5 × 10-6 CFU/g). The probability of infection values of all pathogens were greater than 0.98 with constant annual risk of 1.0 across samples from al markets. Benzo[a]pyrene equivalent of PAH (Benzo(a)pyrene) was highest (8.4 µg/kg) in smoked fishes from Okere Market, well above the European Union limit of 2.0 µg/kg, with BaPeq ILCR values of 5.3 × 10⁻², which indicates high health risks. The Estimated Daily Intake, Hazard Quotient, and Cancer Risk indices for the various heavy metals (mercury, lead, cadmium, arsenic, chromium, nickel, and copper) present in smoked fishes from the various markets exceeded their permissible limits (in all markets) mostly in children, indicating potential chronic exposure and risks. Cancer risk in children ranged from 1.5 × 10-4 – 1.5 across the various markets. Study provided an integrated microbial and chemical risk profiles of smoked fish in Warri for the first time. It provides empirical justification for proactive regulatory reform, continuous monitoring of contamination, the adoption of safer smoking technology, and public health campaigns targeting both market vendors and consumers.
Keywords: Heavy metals, microbial contamination, PAHs, toxicological risk