Polycyclic aromatic hydrocarbons, heavy metals, pesticides and fatty acid levels in five types of widely consumed dried fish samples consumed in Owerri
Date
2023-10
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Federal University of Technology, Owerri
Abstract
The anthropogenic pollutants derived from dumping of agrochemicals and industrial pollutants in the aquatic systems and indiscriminate and destructive fish handling practices poses health hazards to the consumers. These activities have necessitated environmental biomonitoring of fish and fish products which serve as a major and available source of protein. This study quantitatively analysed the polycyclic aromatic hydrocarbons (PAHs), heavy metals, pesticides and fatty acid content in five types of widely consumed dried fish samples in Owerri, Imo State. Heavy metal was determined using Atomic Absorption Spectrophotometer, and pesticides, polycyclic aromatic hydrocarbons and fatty acid content were determined by Gas Chromatography fitted with flame ionization detector. Heavy metals contents in Round fish, Stock fish, Cray fish, Cat fish and Bonga fish showed highest values of 0.27±0.24, 0.04±0.01, 0.06±0.01, 0.06±0.03, and 0.02±00 mg/kg of Lead (Pb), Cadmium (Cd), Nickel (Ni), Mercury (Hg) and Arsenic (As) respectively. While the least concentrations of Pb (0.06±0.04 mg/kg) in Round fish, Cd was not detected in Round fish, Stock fish and Cray fish with the least Cd (0.01±00 mg/kg) in Cat fish; Ni was not detected in Round fish and Stock fish with the least concentration (0.004±0.00 mg/kg) in Cray fish; lowest Hg (0.01±0.00 mg/kg) in stock fish; lowest As (0.004±0.00mg/kg) in Round fish and Cat fish. Pesticide residues of Aldrin, Biphenyl, Carbofuran, Dichlorodiphenyltrichloroethane (DDT), DichhloroBiphenyl, Dichlorvos (2,2- dichlorovinyl dimethyl phosphate-DDVP). Endosulfan, g-chlordane, Glyphosphate, and Hexachlorobenzene (HCB), Heptachlor, Isopropylamine, Lindane, p'p'-DDD, Profenofos, t-nonachlor were detected in varying concentrations in the dried fish samples. Concentrations of aldrin residues in the fish samples were in decreasing order; Stock fish (1.082 ±0.001 mg/kg) > Bonga fish (0.679±0.001mg/kg) > Crayfish (0.205±0.001 mg/kg) > Cat fish (0.001±0.000mg/kg). Biphenyl residues were not detected in all the dried fish samples except in Cat fish (0.378±0.006mg/kg). DDT residues were not detected in all the dried fish samples except in Cray fish (0.318±0.007mg/kg). Concentrations of DichhloroBiphenyl were 0.095±0.041mg/kg in Crayfish, 0.068±0.007mg/kg in Bonga fish, 0.036±0.024mg/kg in Catfish, and .802±0.547mg/kg in Stockfish. Sixteen PAHs were detected in all the fish samples studied. Total PAHs concentrations in decreasing order were Cat fish (11.84±10.00 µ/kg)>Round fish (10.32±8.74 µ/kg)>Bonga fish (8.04±3.00 µ/kg) > Cray fish (3.92±0.54 µ/kg)> Stock fish (3.53±0.08 µ/kg). Twelve fatty acids were detected in varying concentrations in the five dried fish samples. Total Fatty acids concentration in decreasing order were Bonga fish (139.42±12.12 µ/kg) > Cray fish (66.15±4.80 µ/kg) > Cat fish (60.68±2.22 µ/kg) > Stock fish (59.13±4.79 µ/kg) > Round fish (58.28±10.09 µ/kg).The results obtained in this study indicates that indiscriminate dumping of agrochemicals and industrial pollutants in the aquatic systems and indiscriminate and unwholesome fish processing and handling practices as source of pesticides, heavy metals and PAHs. Furthermore, processing and handling practices were implicated in the decrease in the polyunsaturated and the essential fatty acid in the smoked dried fish samples (Bonga fish, Cat fish and Round fish) as compared to the sun dried fish samples(Cray fish and stock fish).
Description
Master’s thesis in environmental biochemistry. It contains pictures and tables.
Keywords
Heavy metals, pesticides, polycyclic hydrocarbons, fatty acids, dried fish, Department of Biochemistry
Citation
Opaleye, B. R. (2023). Polycyclic aromatic hydrocarbons, heavy metals, pesticides and fatty acid levels in five types of widely consumed dried fish samples consumed in Owerri {Unpublished Master's Thesis}. Federal University of Technology, Owerri.