Abstract Persistent organic pollutants (POPs) are synthetic chemicals that have an intrinsic resistance to natural degradation processes, and are therefore environmentally persistent. The introduction of POPs into the environment from anthropogenic activities resulted in their widespread dispersal and accumulation in soils and water bodies, as well as in human and ecological food chains, where they are known to induce toxic effects. Due to their ubiquity in the environment and lipophilic properties, there is mounting concern over the potential risks of human exposure to POPs. POPs include organochlorine pesticides (OCPs), polychlorinated biphenyls (PCBs), dioxins, polyaromatic hydrocarbons (PAHs) and short-chain chlorinated paraffins (SCCPs).Smoked fishes were obtained from three markets in Benin City.
The fishsamples were identified as Oreochromis aureus (Blue tilapia), Scomber scombrus (Atlantic mackerel) and Gymnarchus niloticus (Trunk fish). They were blended to obtain powdered samples and stored in ultra-freezer at 4 ºC. The powdered samples were extracted by Soxhlet extraction procedure using dichloromethane (200ml) POP residues were determined using Soxhlet extraction method and column chromatography for solvent elution. Eluate analysis was by Gas Chromatography (GC) tandem Mass Spectrophotometer (MS) technique.
Concentration of persistent organic pollutants such as lindane, aldrin, endosulfan, heptachlor, dioxins and polychlorinated biphenyls were not detected in the fishes. However, Gymnarchus niloticus from Oluku was found to contain oxirane (0.0362mg/L), tridecyl phthalates (0.0469mg/L) and naphthalene (0.0469mg/L) which are endocrine disruptor and polychlorinated aromatic hydrocarbon (PAH). Similarly, Gymnarchus niloticus and Oreochromis aureus from Aduwawa contained titanium dioxide, 1-chlorooctadecane (SCCP) (0.0214mg/L) and Bis(2-ethylhexyl) phthalate (0.0321mg/L) respectively. Although these levels of organic pollutants were low when compared with the maximum limit of Federal Environmental Protection Agency (FEPA), however, continuous exposure can be harmful if the trend is not checked.
Keywords Organochlorine, Persistent, Chromatography, Extraction, Pesticides.