DEPARTMENT OF ENVIRONMENTAL MANAGEMENT AND TOXICOLOGY

This study evaluated the operational and health risk factors associated with municipal solid waste scavenging in two privately-operated municipal Solid waste dumpsites in Benin City, Edo State. Awell- structured questionnaire was administered to 100 randomly selected scavengers; the questionnaire covered demographics, personal details, and information on the types and frequencies of health hazards encountered by waste scavengers, providing insights into the challenges they face. The findings revealed significant health risks including injuries, respiratory problems, and gastrointestinal illnesses, highlighting the need for interventions to improve the safety and well-being of the scavenging operations. Furthermore, they also face several operational risks due largely to the lack of use of personal protection equipment, resulting in cuts, respiratory issues, and gastrointestinal illnesses, with a notable proportion experiencing frequent headaches and a high prevalence of malaria. We recommend that the operators of the dumpsites should be regulated by the Edo State Waste Management Board, with strict guidelines and punitive measures put in place for lack of compliance. On the part of the dumpsite operators, they should provide all necessary personal protection equipment and enforce their use as a standard operating procedure. Furthermore, first aid equipment for staff, drinking water and bathrooms with soap and water for their sanitation should be provided.

This study was carried out to determine the concentrations of some heavy metals such as nickel, cadmium, mercury and oxidative stress status of tomatoes sold in local markets in Benin City, Edo State, Nigeria. Fresh tomatoes samples were brought from Uselu and Ikpoba hill market in Benin City. The samples were oven-dried at 105°C for 24 hour and grinded to powder. The powdered samples were dissolved in deionized water, filter through whatman filter paper and the volume was made up to 25 ml using 10 ml of 98% nitric acid. The resulting solution was analysed for the presences of heavy metal using using Atomic Absorption Spectrophotometer (AAS, Perkin Elmer model 2130). The results showed that the nickel concentration present fresh tomatoes samples obtained from the two markets ranged from 0.13 mg/kg to 0.16 mg/kg, while the cadmium concentration ranged from 0.11 mg/kg to 0.13 mg/kg. However when compared to W.H.O standard the heavy metal concentration were slightly above the recommended value of 0.10 mg/kg. Also oxidative stress analysis showed that the superoxide dismutase (SOD) value ranged from 3.02 U/g to 3.48 U/g, Catalase (CAT) value ranged from 0.08 U/g to 0.10 U/g , Glutathione peroxidase (GPx) value ranged from 4.96 U/g to 5.73 U/g, while Malondialdehyde (MDA) value ranged from 0.50 U/g to 0.64 U/g respectively. These findings were indicative of environmental pollution due to industrial and vehicular emissions and also the mode of handing and processing of the samples. Although the heavy metals detected in this study are not beneficial to man and plant, low concentration can prove detrimental to health.

ir pollution, particularly fine particulate matter (PM2.5), is a growing environmental and public health concern in urban areas. This study aimed to compare outdoor PM2.5 concentrations during the daytime and nighttime in Benin City, Nigeria. PM2.5 data were collected from three distinct locations (Ugbowo, Sapele Road, and Etete) between October to December 2024 using PurpleAir sensors, with measurements taken six times daily at intervals of 5 hours. Statistical analysis, including paired T-test and ANOVA, was conducted to assess variations between day and night as well as across location and time. Results revealed significantly higher PM2.5 levels during the daytime, with concentrations peaking in December (170.83 µg/m³). The lowest concentration during the day was recorded in the month of October (93.67µg/m³,) while the highest concentration was in the month of December (183.33 µg/m³) at Etete. At night, the least concentration was at Sapele road in the month of October (80.09 µg/m³) with the highest in December (158.32) at Etete. A significant difference (p =1.346e-15) was recorded between the concentrations of daytime and night time PM2.5. A statistical significant difference was tested across locations (p = 0.0088) and months (p = 2e-16). The recorded concentrations far exceed WHO guidelines for PM2.5 concentrations, suggesting a possible health risk for the inhabitants of those locations. Immediate interventions are recommended, including stricter emission regulations, better urban planning, and public awareness campaigns, to mitigate the effects of air pollution and improve public health.

This study examines how environmental pollutants affect aquatic animals' genetic integrity, with a focus on the African catfish (Clarias gariepinus). This study was undertaken is to evaluate DNA damage in C. gariepinus samples obtained from the upstream of Ikpoba River in Benin City, a freshwater body impacted by human activities notably, industrial effluent discharge from a brewery into the river. The piscine micronucleus assay was employed for identifying and measuring breaks in DNA strands in ten (10) samples of C. gariepinus obtained from several points along the river because of its ecological and economic importance as well
as its high sensitivity to chemical stressors, serving as an ecotoxicological indicator species that offers important information about the level of pollution in aquatic habitats. Results showed that fish from the study site had significantly more DNA damage than control groups from unpolluted habitats, indicating that the Ikpoba River's contaminants cause genotoxic stress. It was revealed that heavy metals were among the possible sources of pollution that the study found to be important contributors to the observed genetic damage. Furthermore, the degree of exposure and pollutant concentration were associated with differences in DNA
damage levels among the fish studied. The findings highlight how urgently the Ikpoba River and other comparable water bodies need to be regularly monitored and cleaned up. Such genetic harm has consequences for population health and ecological sustainability in addition to individual creatures, underscoring the wider environmental and socioeconomic effects of water pollution. By laying the groundwork for upcoming ecotoxicological research and conservation tactics, this study is an essential step in comprehending and reducing genotoxic dangers in
aquatic systems.

The discharge of industrial wastewater into aquatic ecosystems poses significant environmental challenges, including the contamination of water bodies with various pollutants and chemicals. This study investigates the effect of non-alcoholic wastewater effluent from a carbonated beverage manufacturing plant on the growth hormone (GH) gene expression of African catfish (Clarias gariepinus). The fish were exposed to concentration levels of 0.5%, 1.5%, 3.5% and 5.0% of the carbonated non-alcoholic wastewater effluent for 96 hours, and the liver was extracted for RNA isolation, DNA extraction, PCR amplification, and gel electrophoresis analysis. The results obtained revealed a dose-dependent effect of the non-alcoholic wastewater effluent on the expression of the GH gene in African catfish. The rise in gene expression in response to soft drink effluent exposure was statistically significant (p < 0.05) according to the statistically significant correlation between the gene’s expression levels at different
concentrations and the comparable control. The gene’s increased expression indicates that the soft drink industry’s effluent is having a detrimental effect on Clarias gariepinus. Therefore, Implementing more effective wastewater treatment processes in industries, conducting thorough Environmental Impact Assessments and increasing public awareness can help reduce the potential harmful effects of wastewater effluent on aquatic organisms.

The quality of aquatic environments is an important contributor to good environmental health. This study assessed the ecological risk assessment of heavy metals in sediments from Ossiomo River, Edo State in order to ascertain the status and degree of contamination. Nine sediment samples were collected using an Eckman Grab from Ossiomo River from November 2021 to January 2022. Samples collected were air-dried, crushed and sieved through a 2mm sieve, pre-treated using standard methods before determining the heavy metal concentrations in Atomic Absorption Spectrophotometer according to the method of the Association of Analytical Chemists. The average mean concentration of heavy metals in sediments from Ossiomo river were1137±760.55 for Fe, 6.83±1.24 for Cu, 28.94±11.93 for Zn, 0.14±0.06 for Cd, 5.80±5.27 for Pb, 9.02±3.80 for Mn, 4.30±1.04 mg/kg for Cr respectively while total hydrocarbon content had an average mean value of 826.80±457.27 mg/kg. The result showed that the concentration of heavy metal were in the following decreasing order: Fe>Zn>Mn>Cu> Pb> Cr>Cd. The composition of
computed Enrichment factor (EF) indicated that there is a moderate enrichment for Fe and Zn, a significant enrichment for Fe, Cr, Cd and a very high enrichment for Pb. Geo accumulation index (Igeo)
showed that sediments from Ossiomo River indicates Cu and Mn were practically unpolluted, Cr and Cd were moderately to heavily polluted, Pb was heavily polluted and extremely polluted. The contamination factor showed a moderate contamination exist for Cu and Mn across the sampled stations from Ossiomo River, a very high contamination exist for Cr, Cd, and Pb across the three sample stations. The contamination degree (CD) showed that a very high degree of contamination(CD ≥ 24) exists across all the three sample stations. Pollution load Index (PLI) showed that Ossiomo river is polluted (PLI>1) by metals. Potential ecological risk index (PERI) showed slight pollution degree of Cu, Zn, and Mn, a medium pollution degree of Cr, a strong pollution degree and a very strong pollution degree of Pb while Cd exhibited an extremely strong pollution degree. The risk level or risk degree for Ossiomo River indicated an extremely strong risk degree or level Dacross the sediments across the stretch of Ossiomo River. The potential ecological risk showed that station1and 3 indicates considerable ecological risk (300<RI≤600), while station 2 indicates a very high ecological risk (RI>600). The heavy metals content exhibited a positive and significant correlation. Therefore the pollution by heavy metals in sediments from Ossiomo River should not be ignored.

Given the widespread global use of hair dyes, which contain chemicals like aromatic amines and oxidative agents, understanding their toxic potential is a critical component of assessing human safety. Drosophila melanogaster served as a model organism due to its well-characterized genome, conserved neurological pathways, and ease of genetic tractability. The flies were exposed to three treatment concentrations of the hair dye (0.05%, 0.5%, and 2.0%). The study assessed overall survival rates and observed climbing ability of the flies using the negative geotaxis assay. Flies were exposed to various concentrations of the dye through dietary administration, and survival was monitored over a 7-day period for the pilot study and a 5-day period for the main study. The relative expression of several key genes including Spitz(Spi), Wingless(Wnt), Eiger(egr), Forkhead box(FOXO), Hedgehog(HH), and Kelch-like ECH-associate protein 1(Keap1) was analyzed. Results demonstrated a dose-dependent response of the organism. The locomotor behavior analysis showed declining climbing ability of the flies at increasing concentrations. The Spi gene, associated with the EGFR pathway, showed a significant increase at the highest (2.0%) concentration. Wnt gene was significantly decreased at the 0.5% and 2.0% concentrations while Eiger gene was increased. The transcription factor FOXO was decreased while the signaling gene HH was significantly increased at high concentrations, indicating the activation of stress-induced and developmental response mechanisms. Conversely, the stress regulator Keap1, involved in the Nrf2 pathway was decreased at the 0.5% and 2.0% concentrations. These findings collectively establish that exposure to the hair dye induces significant neurotoxicity and disturbs fundamental regulatory mechanisms in Drosophila melanogaster, highlighting the need for accurate toxicological evaluation of these cosmetic products.

Access to safe drinking water remains a critical public health challenge in many urban communities, with contaminated water sources posing significant health risks to residents. This study assessed the human health risks associated with household drinking water quality and hygiene practices among residents of BDPA Community, Ugbowo, Benin City, Edo State. A mixed-methods approach combined structured questionnaire surveys of 100 households with physicochemical and microbiological analyses of 30 water samples from borehole, sachet, and bottled water sources. Parameters examined included pH, temperature, turbidity, total dissolved solids, electrical conductivity, total heterotrophic bacterial counts, total coliforms, and Escherichia coli.The study revealed a predominantly young, educated population demonstrating high personal hygiene awareness, yet significant environmental sanitation deficits persisted, with over half of households located near waste dumps or open sewage systems. Borehole water exhibited the highest contamination risk, recording mean heterotrophic bacterial counts of 58.3 colony forming units per milliliter and total coliform counts of 12.3 colony forming units per milliliter, exceeding acceptable safety standards. Sachet water showed moderate contamination with intermittent coliform presence, while bottled water remained consistently safe. Escherichia coli was absent in all samples. A critical behavioral gap emerged as 64% of residents consumed borehole water without treatment, correlating with 24% self-reported water-related illnesses, predominantly typhoid fever. Poor local sanitation infrastructure enables contaminant infiltration into untreated water sources, creating tangible public health threats. Municipal authorities must enforce Nigerian water quality standards and improve community sanitation infrastructure. Public health campaigns should urgently encourage residents, particularly borehole users, to consistently boil or chlorinate drinking water before consumption to prevent disease outbreaks

This study examined the fungal community associated with the topsoil of three major open markets in Benin City, Uselu, Kara, and Oluku, representing different environmental and sanitary conditions. The aim was to enumerate, identify, and compare the fungal species present in the topsoil, focusing on differences between the tomatoes (plant-based) and cattle/beef (animal-based) sections. Topsoil samples were collected aseptically from six locations and cultured on Potato Dextrose Agar using the pour plate technique. Fungal isolates were identified based on macroscopic and microscopic characteristics after staining with lactophenol cotton blue. The mean total heterotrophic fungal count ranged from 12.5 ± 3.3 × 10³ cfu/g in Uselu cattle/beef section to 28.5 ± 3.7 × 10³ cfu/g in Oluku cattle/beef section. Tomato sections of Uselu and Kara showed moderate counts (15.7 ± 2.9× 10³ and 16.2 ± 4.7 × 10³ cfu/g), while Oluku tomato soil had 27.7 ± 6.5 × 10³ cfu/g, indicating greater microbial activity. Ten fungal taxa were identified are Aspergillus species (Aspergillus niger, Aspergillus flavus, Aspergillus parasiticus), alongside Rhizopus sp, Mucor sp, Penicillium sp, Fusarium, Trichoderma sp, and Alternaria sp. Oluku Market exhibited the highest diversity, particularly in tomato sections, where potential aflatoxin producing fungi like; Aspergillus flavus were prevalent. The results of this reveal that market top soils in Benin City have diverse fungi. The frequent presence of toxin-producing Aspergillus species in the locations highlights the need for improved waste management and hygiene to reduce potential public health risks. xi

Petrol station attendants are occupationally exposed to petroleum products and it’s fumes which represents complex mixture of genotoxic agents that possesses an increased risk of various cancers such as that of the oral mucosa. This study assessed the level of genotoxic damage in exfoliated buccal cells obtained from petrol station attendants within Oluku Axis, Benin City, Edo State, Nigeria. Twenty - five exposed petrol station attendants were recruited from five filling stations which includes;
thirteen females and twelve males whose duration of exposure is within zero to five years while nine unexposed healthy individuals were recruited fromthe University of Benin. Buccal cell samples were collected by scrapping of the inner cheeks which was fixed with Carnoy’s reagent and stained using May - Grunwald and Giemsa stains, after which it was analyzed using a light microscope at 100x magnification. A total of 3400 cells were examined for micronuclei and other anomalies such as binucleated and anucleated cells. A significant increase in the frequencies of micronucleated cells, binucleated cells and anucleated cells (12.50, 6.17 and 6.00) with (p < 0.05) were found in the workers exposed as compared to the controls (0.67, 4.50 and 3.33)
respectively. These findings indicate that continuous exposure to benzene have the potential to induce anomalies reflecting DNA strand breaks. This study concludes that petrol station attendants within Oluku Axis experience measurable genetic damagelinked to occupational exposure to petroleum products. It recommends that protective strategies should be implemented by the concerned authorities to minimize exposure to petroleum products.