Background As from last decade, the pollution of water bodies by chemical toxicants has become a topic of public discourse and concern in many countries. Polycyclic aromatic hydrocarbons (PAHs) are carcinogens and being ubiquitous in nature, are daily being released into water bodies as a result of anthropogenic sources. Methods The water samples were collected with plastic bottles/containers by dipping the sampler below the water surface to minimize the contamination of water sample by surface films and cocked below water surface to avoid air entrapment while the fish samples namely Clarias spp (Catfish) and Oreochromis spp (Tilapias) were purchased from fishermen at the bank of the river confluence. Three water samples each were collected from five sample points [A], [B], [C], [D] and [E] created for that purpose at each visit monthly for a period of six months and taken in an ice-cooler box to the laboratory. In all a total of 90 water samples and 20 fish samples were analysed. The water samples were preserved in a refrigerator below 4°C prior to analysis. The concentrations of the sixteen US EPA priority polycyclic aromatic hydrocarbons (PAHs) were investigated using Gas chromatography coupled with Mass Spectrometer detector (GC-MS) after liquid-liquid and solid-liquid extractions. Results The concentrations of the six detected PAHs in water were of the following ranges: Nap(Not Detected {ND} to 0.543), Ph(ND to 0.083) Ant (ND to 0.083), BbF(0.080 to 0.093), BkF(0,083 to 0.093) and BaP(0.083 to 0.113) mg/L with distribution pattern of Nap>BaP > BbF=BkF > Ant = Ph. The mean concentration value of PAHs in Catfish and Tilapia were Nap(2.383 and 1.947), Ph(0.050 and 0.057), Ant(0.057 and 0.057), BbF(0.043 and ND), BkF(0.043 and ND) and BaP(0.050 and ND). The health risk assessment showed that the concentration of Benzo[a]pyrene, a known indicator of the presence of carcinogenic PAHs is of health risk concern. The PAHs were not significantly different in the water and fish respectively and the correlation studies showed that the PAHs were from the same source. Conclusions The study showed clearly that the levels of PAHs in the samples are of concern due to increasing pollution.

Background and Purpose: The root extracts of Dennettia tripetala G. Baker and Milicia excelsa (Welw.) C. Berg was investigated for their in-vitro antioxidant activities.Materials and Methods:  The pulverized roots of Dennettia tripetala and Milicia excelsa were extracted separately by cold maceration using ethyl acetate, methanol, n-butanol and water respectively as the extracting solvents. In-vitro antioxidant, the activity of root extracts was then investigated using DPPH model. The results obtained was analyzed using One-way Analysis of Variance (ANOVA) involving GraphPad Prism 5 Software.Results: The antioxidant assay of various extracts, using 2, 2-diphenyl-1-picrylhydrazyl (DPPH) radical scavenging model, revealed that the ethanol and n-butanol extracts of D. tripetala had better radical scavenging activity with IC50 values of 2.02 and 0.631 µg/mL for ethanol and n-butanol extracts, respectively.  The methanol and ethanol extracts of M. excelsa showed higher radical scavenging capacity with IC50 of 0.194 and 8.84 µg/mL compared to that of the ascorbic acid which had IC50 value of 4.60 µg/mL.Conclusion: The radical scavenging ability of the extracts could be attributed to the presence of flavonoids and phenolics.

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