Gbadebo Clement Adeyinka

Levels and potential toxicity of volatile organic compounds (VOCs) were analyzed in underground water from six locations near a fuel station in Okinni, Osun State, Nigeria. Samples were collected and analyzed using standard procedures. A total number of seven VOCs were detected with varying concentrations, they were: benzene, toluene, chlorobenzene, ethylbenzene, m, p-xylene, o-xylene, and dichloromethane. One-way ANOVA results showed a significant difference (p < 0.5) in VOC concentrations across locations. Most VOCs exceeded USEPA and WHO threshold values, indicating contamination likely from fuel station leachates, as suggested by the low toluene to benzene ratio (T/B < 2). Odour Hazard Index (OHI) values were below 1 in all but location 3, where m,p-xylene, and o-xylene levels were 0.921 and 1.105, respectively, implying that the water from location 3 was not safe given the odour risk assessment.. Carcinogenic risks were more significant through ingestion than dermal contact. Non-carcinogenic risk values were within safe limits except in location 3. Consequently, using the borehole water from location 3 for domestic activities could expose the people of these communities to serious health issues. Therefore, there is a need for urgent attention from the relevant authorities to safeguard the health of this populace.

The quest for safe water due to exponential population growth and climate change has stressed the existing available water source. It is crucial to establish the present pollution level of the Asa River and the health risk it may pose to the people. Samples were collected along the Asa River, Ilorin, Kwara State, Nigeria, and treated using standard methods as stipulated by United States Environmental Protection Agency. The treated samples were analyzed and quantified for dieldrin, endrin, dichlorodiphenyltrichloroethane metabolites, mirex, hexachlorocyclohexane, hexachlorobenzene, and triclosan using the gas chromatography-mass spectrometry. The result showed that the levels of organochlorine pesticides (OCPs) ranged from 0.0045–0.947 μg/kg, 0.0036–0.093 μg/kg, and 0.001–0.007 μg/L in sediment, soil, and water samples, respectively. While the mean concentration of triclosan is 3.78 μg/kg, 2.995 μg/kg, and 0.064 μg/L in sediment, soil, and water samples, respectively. The levels of OCPs were lower than the limits in drinking water as set by World Health Organization and European Union. Health risk assessment for both children and adults was evaluated using non-carcinogenic and carcinogenic risk with the hazard quotient (HQ) and was found to be greater than unity (> 1) in children for the targeted OCPs. Associated cancer risk for OCPs ranged from low cancer risk to moderate risk for humans. The adverse ecological effects of OCPs showed to be very rare to occur and frequent effects may not likely occur except for HCH.

In the present work, the influence of geographical location on the fatty acid profiles, antioxidant potential, as well as cytotoxicity of edible dabai fruit fractions (kernel, skin, and pulp) were analyzed. The fatty acid profiles were determined by Gas Chromatography (GC), and the antioxidant activity was quantified with free 2,2-diphenyl-1-picr/ylhdrazyl, while the cytotoxicity was assessed by the brine shrimp lethality test. The results showed that the samples from Sibu, Serian, and Kapit geographical locations had a high content of the saturated fatty acids, ranging from 46.63% to 53.31% in the three fractions. The highest mono-saturated fatty acids (MUFA) content was found in Sibu. Serian and Kapit kernel fractions MUFA, however, ranged from 21.2% to 45.91%. No fatty acid composition was detected in Bentong and Kanowit. The fatty acid composition and DPPH free radical scavenging antioxidant activity of dabai were statistically independent using a multivariate analysis in different localities in Malaysia. The skin fraction had a more appreciable antioxidant potential and toxicity level than the pulp and kernel fractions. The highest antioxidant activity (EC₅₀ 198.76 ± 1.06 µg/mL) with an LC₅₀ value of 1387.22 µg/mL was obtained from the Sibu skin fraction. Therefore, the fatty acid composition, antioxidant, as well as cytotoxicity analyses of the extracts from different localities indicated that “geographical location” remarkably influenced fatty acid composition, antioxidant activity, and toxicity.

This study evaluated the presence of seven-selected polychlorinated biphenyls and triclosan in the Ojutu River, Osun State Nigeria. The soil, sediment and surface water at five different sampling sites were investigated following the standard analytical procedure. The maximum concentration of targeted PCBs in soil, sediment and water are; 1.02 µg/g, 0.6490 µg/g and 0.02981 µg/mL respectively. While triclosan has 0.0562 ng/g, 0.0457 ng/g and 0.001070 ng/mL in sediment, soil and water samples respectively. The concentrations of some of the selected PCB congeners and triclosan were significant in sediment and soil samples across the sites while the majority analytes showed no significant differences in water samples across the sites. The parameters investigated were found within the WHO maximum permissible limit therefore the water could be considered less susceptible to these pollutants. Other contaminants such as personal care products, pharmaceuticals, heavy metals and micro-pollutants as well as pollution levels associated with microbial load are worthy of investigation to know the actual state of the river for the safety of aquatic lives and the health of humans who depends on this river.

This study aimed to investigate the effect of various sorbate physicochemical properties on the transportation, distribution, fate, and bioavailability as well as remediation of selected hydrophobic organic pollutants in the environment. The natural soil collected from uMngeni River of KwaZulu-Natal province of South Africa and non-ortho and ortho-substituted polychlorinated biphenyls (PCBs) were used in this study. Soil physicochemical properties were characterized and batch studies were carried out to determine the co-effects of PCB stereochemistry and concentration. The results indicated that non-ortho compounds (PCB 77) sorbed more to the soil, (approximately 67%) compared to the di-ortho substituted congener (PCB 52) with 59.5% sorption of the same homolog. The effect of initial concentrations of both non-ortho and ortho-substituted PCBs revealed that low initial PCB concentrations were mostly favored for the sorption while sorption was generally low for ortho-substituted PCBs at high concentration. It is noted from this study that the stereochemistry of PCB congeners may play a critical role in influencing the pollution indices in the environment. Therefore, ortho-substituted congeners may likely be susceptible to aqueous solubility and may likely lead to less affinity to sorb to soil/sediment, and if sorbed have potential to re-suspend back to surface water or leach to the groundwater easily thus posing more risk to aquatic organisms.

This study conducts a comparative assessment of two dumpsites (abandoned and active dumpsite) around Osogbo metropolis Osun State Nigeria. Ten selected heavy metals (HMs) such as arsenic, copper, cobalt, cadmium, chromium, iron, nickel, manganese, lead and zinc were determined. The soil samples were collected, at strategic points to revealed variation in samples. The concentrations of HMs were quantitatively determined using atomic absorption spectroscopy. The results indicated that all the HMs determined were found between below detection limit (bdl) to 0.611 mg/kg and bdl –0.880 mg/kg for abandoned and active dumpsites, respectively. The concentration factor and geo-accumulation intensity revealed no contamination to strong contamination and from uncontaminated to strong contamination intensity, respectively. The concentrations for some of the HMs were below the tolerable recommendation level by National Environmental Standards and Regulation Enforcement Agency and Food and Agriculture Organization/World Health Organization in soil samples. This study recommends periodic monitoring and that possible decontamination of the dumpsite are crucial because these dumpsites were currently in use for crops cultivation such as maize, vegetable bananas, and some other arable plants. Also, HM concentrations in crops should be investigated and monitored at these dumpsites regularly in order to avert detrimental effects of HM pollution, which could manifest many years after exposure, as they are recalcitrant in the environment.

In this study, the pollution levels, sources, and ecological risks associated with five selected heavy metals (chromium, copper, iron, lead, and zinc)were evaluated in surface water, soil, and sediment systems along the Isipingo River, KwaZulu-Natal, South Africa. The surface water, soil and sediment samples collected along the river, were preserved, transported, and stored followed the standard procedures. Soil and sediment samples were digested for heavy metal determination using a microwave digestion system. The digested samples were quantitatively analysed using an inductively coupled plasma optical emission spectrometer (ICP-OES). The results demonstrate that majority of the targeted heavy metals were found below the detection limits in surface water except for iron (Fe), which was found within the concentration range of 9.54 to 46.76 µg/L. Lead was found below the detection limit in water, soil, and sediment samples, while other heavy metals were within the range not detected(ND)to 0.222 µg/kg dry weight and 0.212 µg/kg dry weight in soil and sediment respectively. The ecological risk assessment of the studied metals in soil and sediment systems from this riversignified that water from this river had less probable potential adverse effects on both animals and humans as well as benthic organisms.

The concentration levels of selected trace metals in coal samples collected from three different locations, namely Okaba coal deposit Kogi State, Onyeama coal deposit and Ribadu both in Enugu state...