DEPARTMENT OF ENVIRONMENTAL MANAGEMENT AND TOXICOLOGY

This study was carried out to investigate the effects of the water-soluble fractions of spent and
unspent engine oil on two microalgae, Chlorella vulgaris and Scenedesmus ecornis. The test algae
were exposed to varying concentrations (0%, 5%, 10%, 25%, 50%, 75% and 100%) which were
set up in triplicates. The growth response was monitored every two days for 14 days using a visible
spectrophotometer (Model No. HV-721). The percentage inhibition, dry weight and analysis of
variance (ANOVA) were calculated using Microsoft Excel software. Physicochemical parameters
such as pH, electrical conductivity and total dissolved solids were measured using the appropriate method. The results revealed that growth of both microalgae decreased progressively with increasing concentration, with spent engine oil exhibiting greater toxicity than unspent engine oil. Growth rate analysis consistently favored Chlorella vulgaris in both engine oil. Statistical analysis using ANOVA indicated that it was significant (p< 0.0001) in growth response among the various concentrations for both species. The dry weight analysis revealed that in spent engine oil, the highest cumulative dry weights occurred in the control (391.23 mg/L for Scenedesmus ecornis and 394.24mg/L for Chlorella vulgaris), with marked reduction at 75-100%, with both species recording their lowest biomass at 100% (104.13 mg/L for Scenedesmus ecornis and 117.97 mg/L for Chlorella vulgaris) while in unspent engine oil, dry weight remained relatively high at 5-10% Percentage inhibition analysis revealed growth stimulation at low concentrations (5-10%), particularly in Scenedesmus ecornis exposed to unspent engine oil. In spent engine oil, Scenedesmus ecornis exhibited higher sensitivity than Chlorella vulgaris, while in unspent engine oil, Chlorella vulgaris exhibited greater sensitivity. The total dissolved solids, electrical conductivity, and pH decreased significantly across all concentrations. Spent engine oil is more toxic to microalgae than unspent oil, and the result indicates that Chlorella vulgaris is more suited for bioremediation of aquatic environments contaminated with unspent engine oil, while Scenedesmus ecornis show stronger potential for the bioremediation of water bodies polluted with spent engine oil.

This study investigated the occupational health risks at an airport, focusing on air pollutant concentrations, their spatiotemporal variation, and the associated respiratory health effects among airport workers (N=129). Air quality monitoring was conducted in four areas (Runway, Parking Lot, Departure area, and Reception) during the morning and afternoon periods for carbon dioxide (CO2 ), coarse particulate matter (PM10 ), and fine particulate matter (PM2.5 ). The data were analysed via ANOVA and paired samples t tests. A survey collected data on workers' sociodemographic, workrelated risks, and self-reported respiratory symptoms. Environmental monitoring identified PM2.5 as the primary air quality hazard. The highest observed mean PM2.5 concentration (24.1 μg/m3) exceeded the strict WHO 24-hour guideline. Statistical analysis confirmed significant spatial variation in PM2.5, with the Runway and Parking Lot acting as hotspots and a highly significant temporal spike in the afternoon (p=0.001). Coughing was the most prevalent reported symptom (57.4% of workers). Chi-square tests revealed a strong correlation between respiratory symptoms (cough, phlegm, shortness of breath, and chest pain) and both smoking and a family history of chronic respiratory issues (p≤0.007 for all). Furthermore, workers demonstrated critical systemic failure in safety protocols, with 83.7% lacking knowledge of the proper use of personal protective equipment (PPE) and 96.9% unaware of routine air quality monitoring. The airport environment presents a substantial and avoidable health risk driven by noncompliant PM2.5 levels and systemic safety management failures. Recommendations include implementing mandatory, hands-on PPE training, establishing a transparent PM2.5 monitoring system in hotspots, and creating an occupational health program to screen and counsel high-risk

This study investigated the occupational health risks at an airport, focusing on air pollutant concentrations, their spatiotemporal variation, and the associated respiratory health effects among airport workers (N=129). Air quality monitoring was conducted in four areas (Runway, Parking Lot, Departure area, and Reception) during the morning and afternoon periods for carbon dioxide (CO2 ), coarse particulate matter (PM10 ), and fine particulate matter (PM2.5 ). The data were analysed via ANOVA and paired samples t tests. A survey collected data on workers' sociodemographic, workrelated risks, and self-reported respiratory symptoms. Environmental monitoring identified PM2.5 as the primary air quality hazard. The highest observed mean PM2.5 concentration (24.1 μg/m3) exceeded the strict WHO 24-hour guideline. Statistical analysis confirmed significant spatial variation in PM2.5, with the Runway and Parking Lot acting as hotspots and a highly significant temporal spike in the afternoon (p=0.001). Coughing was the most prevalent reported symptom (57.4% of workers). Chi-square tests revealed a strong correlation between respiratory symptoms (cough, phlegm, shortness of breath, and chest pain) and both smoking and a family history of chronic respiratory issues (p≤0.007 for all). Furthermore, workers demonstrated critical systemic failure in safety protocols, with 83.7% lacking knowledge of the proper use of personal protective equipment (PPE) and 96.9% unaware of routine air quality monitoring. The airport environment presents a substantial and avoidable health risk driven by noncompliant PM2.5 levels and systemic safety management failures. Recommendations include implementing mandatory, hands-on PPE training, establishing a transparent PM2.5 monitoring system in hotspots, and creating an occupational health program to screen and counsel high-risk

The natural ripening process of fruit involves a series of physical and chemical transformations, leading to sweetness, coloration, softness, and enhanced taste. This research aimed to explore the impacts of two ripening methods on the nutritional value, namely; calcium carbide and woodash, on orange. Freshly plucked green matured oranges were used for the determination of proximate analysis and mineral content (potassium (k), phosphorus (p), calcium(Ca), sodium(Na). Calcium carbide had the highest Ca, Mg, P, Na (111.10 mg/100g, 108.25mg/100g, 50.05mg/100g and 50.30mg/100g respectively and also shows significant differences between the two ripening methods based on the contents respectively. The results of the study showed that
using calcium carbide as a ripening agent significantly reduced the nutrients in the fruit. Because of itspossible effects on nutritional quality, ash has been used as a preservative in food preservation. Thestudy evaluates changes in important nutritional characteristics such vitamins, minerals, and antioxidantsusing analytical techniques, such as nutritional analysis with untreated oranges. The results shed light onthe effectiveness of ash as a preservative and how it affects oranges' nutritional value.

This study investigates the concentration of selected heavy metals—lead (Pb), cadmium (Cd), copper (Cu), zinc (Zn), and nickel (Ni)—in commonly consumed fruits sold in urban markets within Benin City, Nigeria, with the aim of assessing their safety and potential health risks to consumers. Urban agriculture, while vital for food security and nutrition, faces contamination challenges from industrial emissions, vehicular activities, and waste mismanagement that lead to heavy metal accumulation in soils and crops. Fruit samples including mangoes, oranges, bananas, pawpaw, and pineapples is analysed for heavy metal concentrations and compared against international safety standards set by the World Health Organization (WHO) and Food and Agriculture Organization (FAO). Human health risk assessment models is applied to estimate potential non-carcinogenic and carcinogenic risks associated with fruit consumption. The study seeks to identify possible sources of contamination, provide
evidence-based insights into the safety of urban-grown fruits, and guide policymakers, regulators, and consumers in promoting safer urban agricultural practices and protecting public health.

This study was carried out to assess the effects of cassava and maize effluents, on the growth of two freshwater microalgae (Scenedesmus ecornis and Chlamydomonas reinhardtii). Cassava and maize effluent from agro-processing facilities produces large quantities of wastewater. The test algae were grown in seven concentrations (0%, 5%, 10%, 25%, 50%, 75% and 100%), which were set up in triplicates. Growth response of the test microalgae was monitored at two-day intervals for 14 days using a visible spectrophotometer (Model No. HV-721). The growth rate, percentage inhibition, and analysis of variance (ANOVA) were computed using Microsoft excel software. Physicochemical parameters such as hydrogen ion concentration (pH), electrical conductivity, and total dissolved solid (TDS) were also determined. The results indicated that the growth response of Scenedesmus ecornis and Chlamydomonas reinhardtii increased with the increasing concentrations of cassava and maize effluent. Statistical analysis using ANOVA showed that the growth response was statistically significant (p < 0.05) among the various concentrations for both species. Overall, Scenedesmus ecornis recorded higher biomass relative to Chlamydomonas reinhardtii. Dry weight of Scenedesmus ecornis recorded the highest biomass of 398.53mg/L, 331.93mg/L, 306.86mg/L, 362.9mg/L, 175.55mg/L, 123.75mg/L and 85.28mg/L at 100%, 75%, 50%, 25%, 10%, 5% and 0% concentrations respectively. Percentage inhibition result revealed that both microalgae had a stimulatory response to the effluents. This stimulatory response was found to follow a concentration gradient with increased stimulation as effluent concentration increased. Scenedesmus reached -450% inhibition at the highest concentration (100%), while Chlamydomonas peaked at -330% at 100% concentration, this makes Scenedesmus ecornis a better candidate for a successful bioremediation. Results of the physicochemical parameters showed a concentration dependent relationship. pH was observed to decrease with increasing concentration across effluent medium. Based on the findings in this study, it can be deduced that both test microalgae can be utilized for the bioremediation of cassava and maize effluent polluted areas.

Water is humanity's lifeblood, flowing across all forms of life, culture and economies around the world, it is a human right and a common development denominator for shaping a better future. Clean water is necessary for life, health, and development. It plays a critical role in sustaining ecosystems, supporting agriculture, promoting sanitation, and safeguarding public health. Every type of life depends on water, and thankfully, there is an abundance of water on Earth that will never run out of supply. Despite the optimistic outlook presented above, water scarcity can and frequently does exist, and this trend will only worsen as the world's population grows. Water quality values aren't definite; instead, they are measured according to guidelines from authorized bodies. The quality of drinking water is unequivocally linked to public health. Access to safe and clean water is a fundamental human right and is essential for preventing a significant burden of disease worldwide. Physical parameters influence the aesthetic quality of water and indirectly indicate the presence of pollutants. Water intended for domestic use must be free from pathogenic organisms such as Salmonella, Vibrio cholerae, and Escherichia coli. Ohovbe is a semi-urban area where residents rely primarily on boreholes and wells for drinking and domestic purposes. The socio-demographic data of residents of Ohovbe community were obtained, water access and availability data and also their health status and awareness. The physicochemical and bacteriological parameters of water samples were also analyzed. To safeguard public health, residents should be encouraged to boil or filter their drinking water before consumption, and local authorities should ensure regular monitoring of water sources to maintain compliance with WHO standards

Heavy metal contamination of freshwater bodies poses a significant environmental and public health concern, particularly in urban regions with increasing anthropogenic activities. This study aimed to evaluate the concentrations and health risks of selected heavy metals in the Ogba River, Benin City, Nigeria. Water samples were collected across three locations (upstream, midstream, and downstream) over three months to assess both spatial and temporal variations. The samples were analyzed for copper (Cu), chromium (Cr), nickel (Ni), lead (Pb), manganese (Mn), and cadmium (Cd) using an atomic absorption spectrophotometer. The data were analysed using SPSS version 22, and descriptive statistics and one-way ANOVA were employed to assess variations, with p < 0.05 considered statistically significant. Results revealed that Ogba River water showed elevated levels of Cr, Ni, Pb, Mn, and Cd, often exceeding WHO and, in some cases, NESREA permissible limits, while Cu remained within safe limits. Children had higher Chronic Daily Intake (CDI) values than adults. Hazard Quotient (HQ) indicated low risk for Cu, Ni, and Mn, but potential non-carcinogenic risk from Cr, Cd, and Pb. Combined Hazard Index (HI) exceeded 1 at all stations, with children more vulnerable. Incremental Lifetime Cancer Risk (ILCR) for Cr, Cd, and Pb surpassed USEPA limits, with Cr posing the highest cancer risk. In conclusion, Ogba River is contaminated with heavy metals exceeding safe limits and posing health risks, particularly to children. Immediate monitoring and pollution control are needed to protect human health and the river ecosystem

Heavy metal contamination from mechanic workshops poses a major environmental challenge due to the continuous accumulation of toxic metals in soil, which can affect microbial activities, reduce soil fertility, and pose health risks to humans and other organisms. This study assessed the effectiveness of hydroxyapatite (HAp) and phosphate solubilising bacteria (PSB) (Pseudomonas sp.) in remediating heavy metal contaminated soil collected from a mechanic workshop. The research involved four treatments: soil only (control), soil + PSB, soil + HAp, and soil + PSB + HAp. Microbial counts and heavy metal concentrations (Fe, Cu, and As) were analyzed after incubation. The total heterotrophic bacterial count (THBC) increased from 2.5 × 10⁵ CFU/g in soil treated with PSB alone to 2.75 ± 0.71 × 10⁵ CFU/g in soil treated with both PSB and HAp, indicating enhanced microbial growth due to the combined amendment. The concentrations of iron (Fe) and copper (Cu) decreased significantly in all treated samples compared to the control. Fe reduced from 7561.97 mg/kg in the control to 6197.18 mg/kg in the combined treatment, while Cu decreased from 205.32 mg/kg to 150.19 mg/kg. Percentage reductions of 18.05% (Fe) and 26.85% (Cu) were recorded for the combined treatment, while arsenic (As) was not detected in any sample. These findings demonstrate that hydroxyapatite and Pseudomonas sp. act synergistically to immobilize and reduce heavy metal concentrations in contaminated soils. The combination improves microbial activity, enhances metal precipitation, and reduces the bioavailability of toxic metals. The study concludes that the combined use of hydroxyapatite and phosphate solubilising bacteria is an efficient, low-cost, and environmentally friendly method for remediating heavy metal–polluted soils from mechanic workshops in Nigeria.

Meteorological conditions play an important role in ambient air pollution by influencing the emissions, transport, formation, and deposition of air pollutants both directly and indirectly. The relationships between meteorological parameters and particulate matter concentrations were investigated in ten (10) randomly selected locations within the University of Benin, Benin City, Nigeria. The particulates (PM1.0, PM2.5, and PM10), relative humidity (RH), and temperature were quantified using Dienmern DM106A Air Quality Detector, while the wind speed (WS) was monitored using the Holdpeak 866B digital anemometer respectively for four weeks. The ambient temperature and relative humidity and the concentrations of PM2.5 and PM10 obtained in this study were 34.1 to 36.1℃; 62.9 to 38.1%; 0.;8 to 1.9m/s 25.9 and 30.5µg/m3 .and 57.0 to 62.2 µg/m3. The values obtained were all above the recommended allowable limits. There were generally weak associations between air pollutants and meteorological parameters (R=-0.261, - 0.282, and -0.271; p<0.001)). The air quality index assessment revealed that the particulate matter AQI status was primarily unhealthy. The high levels of particulate matter obtained in the study call for the urgent need for awareness of air pollution-related health effects and preventive measures to reduce the concentrations of Particulate matter pollution. within the University