Godswill Okeoghene Tesi

This study was carried out to determine polycyclic aromatic hydrocarbons (PAHs) in spices commonly consumed in south-south, Nigeria in order to provide data on their occurrence, distribution pattern health effects. A total of fifty-two (52) commonly consumed spices were collected from retailers in different markets from south-south, Nigeria. The PAHs in the spices were extracted by ultrasonication using dichloromethane/n-hexane and a gas chromatograph coupled with mass spectrometry was used to quantify the content of 16 PAHs in the extracts. The concentration of ∑16 PAHs in the spices ranged from 0.6 to 36.4 mg kg-1. The obtained BaP and PAH4 concentrations were below the recommended maximum levels set by the European Commission. The compositional pattern of PAHs in the spices was in the order: 3-> 4-> 5-> 6-> 2-rings. The risk assessment indicated that there is no health risks associated with the intakes of these spices.

The combination of materials have seriously encouraged the removal of contaminants as these contaminants can pose threats to human and acquatic lives and general ecosysytem. In this work, magnetite-Eichornia crassipes nanocomposite (MECN) was synthesized by doping magnetite nanorpaticles with Eichornia crassipes at 2:1. The synthesized MECN was characterized for their functional groups, morphology and topography, particle size, composition and crystallinity. The Fourier Transform Infrared (FTIR) results showed prominent reactive functional groups for the absorption bands at 3765.00 cm-1. 2926 cm-1. 2860.50 cm-1. 2354.55 cm-1. 1876.00 cm-1. 1629.81 cm-1. 1381.20 cm-1. 1075.33 cm-1 and 776.62 cm-1 which represents C=C stretching of the alkenes, C-H asymmetric stretching, C-H symmetric stretching, C=O stretching of the carbonyl group, C=C stretching of the alkenes, N-H bending of the amide group, N-O symmetric stretching of the nitro group, C-O stretch of the ether group, Fe-O stretch of magnetite respectively. The energy dispersive x-ray (EDX) results revealed the elemental constituents in weight percentages showing Fe (12.22 %), O (7.20 %), Au (0.50 %), C (0.33 %), Ca (3.23 %), N (3.20 %), Si (66.10), Na (2.22 %), Mg (5 %) respectively. Powdered x-ray diffraction techniques (PXRD) revealed that the synthesized MECN is in a non-crystalline state. The morphology of the synthesized nanocomposite was found to be spherical with a porous surface topography from scanning electron microscope (SEM) analysis. The average particle size of the nanoparticles as characterized by transmission electron microscope (TEM) was found to be 6.3 nm.

This study investigated the presence of organophosphate pesticides (OPPs) in fifty herbal mixture samples obtained from major towns in Bayelsa, Nigeria, to evaluate their safety. OPPs were quantified using a gas chromatograph (GC) coupled with a mass-selective detector after solvent extraction. The results showed that all fifty herbal mixtures contained detectable levels of OPPs, with detection frequencies for individual OPP congeners ranging from 52% for pyraclofos to 90% for diazinon, the most frequently detected congener. At least three OPPs were detected in each sample. Total OPP concentrations varied from 3.80 to 48.0 ng·L-1, 4.50 to 51.6 ng·g-1, and 2.96 to 18.1 ng·g-1 in liquid, powder, and capsule herbal mixtures, respectively. These concentrations were below the maximum residue limits (MRLs) set by the European Pharmacopeia. Computed hazard index (HI) values were generally < 1, indicating no significant non-carcinogenic risk associated with the ingestion of these herbal mixtures. The contribution of individual OPP congeners to the HI followed the order: O-ethyl O-4-nitrophenyl phenylphosphonothioate (EPN) > diazinon > pirimiphos-methyl > quinalphos > chlorpyrifos > chlorpyrifos-methyl. This study underscores the need for continuous monitoring and the application of rigorous scientific standards to herbal mixtures to ensure consumer safety.

This study investigated the adsorption and desorption performances of water hyacinth leaves powder (WHLP) and water hyacinth roots powder (WHRP) towards Pb ²⁺ , Co ²⁺ , Zn ²⁺ and Ni ²⁺ in industrial wastewater. The parameters influencing the process were assessed, models were proposed to explain the both the equilibrium and kinetics of the sorption process and desorption study was conducted using different HNO ₃ and NaOH concentration. The results showed that comparatively, the metal uptake capacity of water WHLP was higher than WHRP as examined by the investigated parameters. The biosorption data fitted to both Langmuir and Freundlich isotherms. The kinetics of the process follows a pseudo-second order reaction model because it provides good linearization of the experimental data. In addition, relatively successful metal ions desorption from the biosorbents were recorded with both NaOH and HNO ₃ solutions.

The presence of heavy metals in consumer products, particularly in personal care items like soaps, poses potential health risks to consumers. This study aimed to determine the concentrations and risks of Pb, Ni, Zn, Co, Cd and Cr in commonly used bathing soaps available in the Nigerian market. A total of seventeen bathing soaps comprising of medicated, moisturizing, toilet and skin whitening soaps were obtained for this study. Analytical procedures under satisfactory conditions were harnessed to determine the various concentrations and the results revealed varying concentrations of Pb (0.08 to 0.39 mg/kg), Ni (0.05 to 0.33 mg/kg), Zn (0.10 to 6.42 mg/kg), Co (0.04 to 1.93 mg/kg), Cd (0.02 to 0.09 mg/kg), and Cr (0.01 to 0.19 mg/kg) across the different soap categories. The systemic exposure dosage (SED) values for these metals obtained from the use of these bathing soaps were below their respective provisional tolerable daily intake or recommended daily intake values. The margin of safety (MoS) values obtained were greater than 100 which indicated that the concentrations of the metals in these soaps do not present considerable risk to the users. The findings underscore the importance of regular monitoring and regulation of heavy metal content in consumer products, particularly personal care items like soaps. As prolonged exposure to these metals, even in trace amounts, may have adverse effects on human’s health and long-term toxicity. Therefore, stringent quality control measures and regulatory standards are imperative to safeguard public health and ensure the safety of consumers in Nigeria.

This study examined the sorption of Mn(II) ions from waste using dried and blended water hyacinth root (WHR). It focused on how the major process parameters influenced the sorption process. Mathematical models were proposed to explain both the equilibrium and kinetics of biosorption. A desorption study was conducted using different HNO3 and NaOH concentrations. An application study using actual industrial effluent was evaluated to analyze the fitness of the biosorbent at optimal batch conditions. The results demonstrated that the increasing initial Mn(II) ion concentration decreased Mn(II) ion removal, while an increase in the sorbent dosage increased its removal. For the rate of biosorption, the contact time was rapid between 15 and 45 min, and the maximum Mn(II) ion was removed within the initial 60 min. Equilibrium sorption was attained at pH 7, where maximum Mn(II) ion uptake was 94 %. The results also showed that Mn(II) ion biosorption at 30 °C and pH 7 for water hyacinth roots could be modeled by Langmuir and Freundlich isotherms and the pseudo-2nd order model. Furthermore, an effective desorption of Mn(II) was obtained with solutions of both NaOH and HNO3. The results also showed that the percentage biosorption and desorption of Mn(II) from the industrial wastewater were 64.68 and 27.95 %, respectively.