Osun River Research Articles

Assessment of flood vulnerability in Osun River Basin using AHP method

Flooding is a global natural disaster that occurs when water rises over normal levels and damages infrastructure, buildings, and land. Lately, a substantial rise has occurred in the frequency and severity of floods in Nigeria due to urbanization, population growth and climate change. This study aims to identify areas in the Osun River Basin (ORB) in southwest Nigeria that are at risk of flooding as a result of increased rainfall patterns that can induce river flooding. 10 flood factors contributing to flood susceptibility were obtained around the study area. These remote sensing data were analyzed using a weighted overlay on ArcGIS. The Analytic Hierarchy Process (AHP) was particularly applied in analysing the flood factors and creating the flood susceptibility maps. Results obtained showed that flood events are probable in areas along the river bank, some areas that are low-lying terrains and areas where there is high rainfall. Ogun State falls within the areas with the lowest digital elevation, therefore the state is very highly susceptible to flooding from the tributaries of the Osun River. Areas such as Ijebu North, Ijebu North East, Ijebu East and Ijebu Ode were identified as highly susceptible to flooding from the maps created. This study will further help stakeholders and policymakers in reducing the impact of flooding in these areas.

Occurrence, source identification and risk assessment of polybrominated diphenyl ethers in water and sediments of Osun River, Nigeria

BackgroundIn the present study, the concentrations of polybrominated diphenyl ethers (PBDEs) in water and sediments of Osun River, Nigeria were determined.MethodsThe obtained water samples were subjected to liquid-liquid extraction while the sediment samples were subjected to extraction using n-hexane and acetone. The extracts were quantified using a Gas Chromatography-Mass Spectrometer to assess their distribution, source identification, and ecological risk assessments.ResultsThe results of the study indicated that BDE-99, BDE-183, and BDE-209 were not detected in the water samples while BDE-28 had the most significant mean contribution (0.057 mg/L w.w) to the total PBDEs in the water samples. The sediment samples were dominated by enhanced concentrations of BDE-100 congener (mean concentration 0.184 mg/kg d.w). The compositional profiles of the PBDE congeners indicated the abundance of higher BDEs in the sediment samples compared to the water samples, a phenomenon attributed to the lower reduction rate and lower water solubility of the higher BDEs. Source identification indicated that commercial deca-BDE mixtures might represent the major source of PBDEs in the studied river. Risk assessment of PBDEs in water samples showed that the mean concentrations of tri-BDE, tetra-BDE, penta-BDE, and hexa-BDE exceeded the acceptable limits, suggesting adverse health risks to the public. Ecological risk assessment of PBDEs in sediment samples showed medium ecological risk by hexa-BDE (0.1 ≤ RQ ≤ 1) and high ecological risks due to tri-, tetra-, penta-, and deca-BDEs (RQ > 1).ConclusionThe study concludes that efficient and cost-effective remediation strategies should be developed and employed in the abatement of these persistent organic pollutants from the environment.

EFFECTS OF PESTICIDES RECIDUES ON TILAPIA ZILLII, SEDIMENT AND SURFACE WATER OF ERINLE DAM AND RIVER OSUN IN OSUN STATE

This study investigates the effects of selected pesticides on the health of aquatic ecosystems and humans in Erinle Dam and River Osun, Osun State, Nigeria. Focusing on Tilapia zillii, a commonly consumed fish in the region, the research assesses the potential health risks posed by pesticides found in the water, sediments, and fish tissues. Samples were collected following APHA guidelines and tested for pesticides like DDT, Heptachlor, Dieldrin, Aldrin, and Chlorpyrifos. The findings revealed high levels of DDT and Chlorpyrifos in both the water and fish, with Erinle Dam showing higher concentrations than River Osun. Specifically, DDT levels in River Osun's water averaged 199.08mg/kg, while Erinle Dam had 271.58mg/kg. Dieldrin and Chlorpyrifos also showed high concentrations, with Heptachlor and Aldrin absent in the water samples from both sites. Fish tissue analysis indicated higher pesticide levels in specimens from Erinle Dam compared to River Osun. DDT and Chlorpyrifos concentrations were notably high, while Dieldrin, Aldrin, and Heptachlor were present in lower amounts. Similarly, sediment analysis showed Erinle Dam with higher pesticide concentrations, particularly for DDT, Dieldrin, and Chlorpyrifos, while Heptachlor and Aldrin were absent.Overall, the study highlights significant pesticide contamination in Erinle Dam and River Osun, posing health risks to local fish consumers and indicating a need for stringent pesticide regulation and monitoring in the region.

Evaluation of the Performance of Categorical Boosting Algorithm for Flood Prediction in Osun River Basin

Evaluation of the Performance of Categorical Boosting Algorithm for Flood Prediction in Osun River Basin

Assessment of aquaculture wastewater impact on Osun river, Ede, Nigeria

A study was conducted to determine the impact of aquaculture wastewater discharged from Alhaji Aagberi Fish Farms' fish pond in Ede, Osun State. Samples were collected from four different points around the pond and subjected to physicochemical and metal content analyses to determine the heavy metal levels. The physicochemical tests included pH, temperature, colour, electrical conductivity, chloride, dissolved oxygen, nitrate, phosphate, and turbidity. Biological tests such as fecal coliform, heterotrophic plate count, and adenosine triphosphate tests were also performed. The results showed that the samples had acceptable pH, temperature, and electrical conductivity levels. The colours of the samples ranged from light greenish, greenish, and light brown to no colour. Some samples had a fish-like odour, while others had no odour. The samples had an average chloride content ranging from 99.4 ± 0.2 mg/L to 149.9 ± 0.2 mg/L, dissolved oxygen from 1.94 ± 0.01 mg/L to 2.31 ± 0.02 mg/L, nitrate content from 2.99 ± 0.01 mg/L to 3.12 ± 0.01 mg/L, and turbidity from 2.44 ± 0.01 mg/L to 2.97 ± 0 mg/L. All of these values were within the regulatory limits. The metal content analyses showed that zinc, lead, mercury, and chromium were within acceptable limits. The bacterial counts ranged from 1.5 x 102 CFU/mL to 4.5 x 102 CFU/mL, leading to four genera of gram-negative and gram-positive bacteria, respectively. Aspergillus spp., Mucor, and Penicillum were the fungal isolates obtained from the samples. Therefore, to prevent harmful bacteria from the fish pond, the microbial load should be reduced by regulating and monitoring the water supplied and discharged from the pond ensuring it is free from harmful bacteria.

Loss of Critical Ecosystem Services in the Osun River Catchment, Southwest Nigeria

Loss of Critical Ecosystem Services in the Osun River Catchment, Southwest Nigeria

Occurrence, source apportionment, and ecological risk assessment of organophosphate esters in surface sediment from the Ogun and Osun Rivers, Southwest Nigeria

Organophosphate esters (OPEs) are synthetic chemicals widely used as e.g., flame retardants and plasticisers in various consumer products. Due to the toxicity of OPEs in aquatic ecosystems, exposure of fauna and flora to these compounds is of potential concern. In this study, the concentrations, profiles, sources, and ecological risk of eight OPEs were investigated in the sediments from the two major rivers in southwest Nigeria. Concentrations of ∑OPEs in surface sediments were in the range 13.1 – 2110 ng/g dry weight (dw) (median: 378 ng/g dw) in the Ogun River and 24.7—589 ng/g dw (median: 174 ng/g dw) in the Osun River. These concentrations are broadly within the range of those reported in surface sediment in previous studies conducted in other locations around the world. Tris (2-butoxyethyl) phosphate (TBOEP) was the dominant OPE in the sediment samples with a median concentration of 337 and 126 ng/g dw for the Ogun and Osun Rivers respectively, while tri-n-butyl phosphate (TnBP) was not detected in any sample. Excluding TBOEP, the chlorinated organophosphate esters: tris(2-chloroethyl) phosphate (TCEP), tris(2-chloro-propyl) phosphate (TCIPP), and tris(1,3-dichloro-2-propyl) phosphate (TDCIPP) were the dominant OPEs in the Osun River, while the aryl-OPEs: triphenyl phosphate (TPHP), 2-ethylhexyl diphenyl phosphate (EHDPP), and tri-m-tolyl phosphate (TMTP) were dominant in the Ogun River. Under a median exposure scenario, moderate ecological risk was predicted from exposure to TCIPP in the Osun River. In contrast, under a high exposure scenario, concentrations of TDCIPP (risk quotient, RQ = 5.33—5.37) constituted a high ecological risk in both rivers, with moderate risks observed for TBOEP (RQ = 0.022—0.18) and TCIPP (RQ = 0.097 – 0.16). Therefore, the risk to aquatic organisms from concomitant exposure to mixtures of OPEs in freshwater ecosystems requires further investigation.Graphical

Remotely Sensed Assessment of Mining Severity Within Buffer Zones of Osun River: Implications for Drinking Water Quality, Biodiversity Protection, and Status as UNESCO World Heritage Site

Remotely Sensed Assessment of Mining Severity Within Buffer Zones of Osun River: Implications for Drinking Water Quality, Biodiversity Protection, and Status as UNESCO World Heritage Site

RAINFALL AND RUNOFF RELATIONSHIP FOR DETERMINATION OF WATER ABSTRACTION POTENTIAL OF RIVER OSUN, SOUTHWESTERN, NIGERIA

The hydrological regime is characterized by high variability of rainfall and runoff distribution. The hydrologist finds it difficult to make accurate prediction of water abstraction by various dams. Inspite that Osun is blessed with abundant water resources being one of the states that supplier water to resident in Osun state, water supply is made inadequate due to lack of schedule of water by facilities abstracting water from the river. In this study, the Rainfall-Runoff Relationship for Determination of Water Abstraction Potential of River Osun was investigated. The model developed was a linear regression approach considering effects of past rainfall on the runoff of the effluent streams. Forty (40) years rainfall data collected from 1974 – 2012 were used to estimate corresponding runoff using empirical approach. The rainfall were repressed against runoff and the corresponding runoff arrived at regression coefficient of 0.912 and 0.896 respectively. Generated runoff for River Osun were determined. The data could serve as a veritable hydrological input in the allocation of water for the dams abstracting water on the river. It is recommended that to find a lasting solution to the menacing frequent lack of water by dams abstracting water on River Osun.

Resourcefulness of propylprodigiosin isolated from Brevundimonas olei strain RUN-D1

A novel red-pigmented bacterium was isolated from a water sample collected at Osun River, Ede. Morphological and 16 S rRNA gene sequencing revealed that the bacterium is a strain of Brevundimonas olei, while its red pigment was identified using UV-visible, FTIR and GCMS as a derivative of propylprodigiosin. The maximum absorbance of 534 nm, the FTIR’s 1344 cm− 1 peak of prodigiosin’s methoxyl C-O interaction, and the molecular ions from GCMS confirmed the pigment’s identity. The pigments production was temperature-sensitive (25 °C), lost at > 28 °C, and in the presence of urea and humus. In addition, the pigment turned pink in the presence of hydrocarbons, while its red colour was retained with KCN and Fe2SO4, and enhanced by methylparaben. Furthermore, the pigment is stable in high temperature, salt, and acidic conditions, but changed to yellow in alkaline solution. The pigment, identified as propylprodigiosin (m/z 297), demonstrated broad-spectrum antibacterial activities against clinically important strains of Staphylococcus aureus (ATCC25923), Pseudomonas aeruginosa (ATCC9077), Bacillus cereus (ATCC10876), Salmonella typhi (ATCC13311), and Escherichia coli (DSM10974). The ethanol extract has the highest zones of inhibition of 29 ± 3.0, 26 ± 1.2, 22 ± 3.0, 22 ± 1.5, and 20 ± 2.0 mm, respectively. Furthermore, the acetone pigments interacted with cellulose and glucose such that increasing glucose concentrations showed linearity at 425 nm. Finally, the fastness of the pigments to fabrics was excellent, with percentage fadedness of 0 and − 43% light and washing tests, respectively, in the presence of Fe2SO4 as the mordant. The antibacterial nature of prodigiosin solutions and their good textile fastness to fabrics could be essential in manufacturing antiseptic materials such as bandages, hospital clothing and agricultural applications such as tubers preservation.Key points

Survey of parasitic fauna of some fishes from Osun river, Osun state, southwestern, Nigeria

Survey of parasitic fauna of some fishes from Osun river, Osun state, southwestern, Nigeria

The influence of temporal variation of some limnological parameters on finfish assemblage in Osun River, Nigeria.

BackgroundAnthropogenic activities is a major factor that determines the condition and sustainability of an environment. The nature and type of activities will determine the health, ecosystem services and general well-being of the environment. These activities have increased as a result of industrialization and urbanization, notwithstanding pressure on fish species for balanced nutrition and economic returns. The paucity of documented information about the limnological parameters and finfish assemblage in Osun River nessiciated this study.ResultsMean temperature (18.7 ± 2.69 °C) and dissolved oxygen (3.2 ± 0.54 mg/L) values were below the recommended limit for fish survival, pH (7.1 ± 0.25) and ammonia (1.2 ± 0.18 mg/L) were within and above the recommended limits. The river had a total of 4544 finfish belonging to 11 families and 19 species. Chrysichthys nigrodigitatus, sampling zone A and Cichlid family had the highest abundance in the river with 21.00%, 24.20% and 32.50% respectively.Fin fish abundance had a negative relationship between dissolved oxygen (r = − 0.032), ammonia (r = − 0.668), pH (r = − 0.819); temperature and DO with ammonia(r = − 0.668, r = − 0.590) and pH (r = − 0.043, r = − 0.011) respectively. Dissolved oxygen (b = − 137.1), ammonia (b = − 522) and pH (b = − 93.4) had a negative effect on finfish assemblage in the river. Significant correlated values (p < 0.05) were observed between fin fish and temperature (p = 0.008), ammonia (p = 0.017), pH (p = 0.001). dissolved oxygen (b = − 2.14), ammonia (b = − 2.72) and pH (b = − 1.97) had a negative association with fin fish abundance while significance (p < 0.05) were observed with dissolved oxygen (p = 0.048).ConclusionIt is worthy to note that human activities principally dictates the quality and quantity of limnological parameters which directly affect finfish assemblage; therefore proper environmental management is essential for sustenance of finfish in the river as elaborated by the United Nations Sustainable Development Goals.

Gold mining impairs the biological water quality of a culturally important river and UNESCO World Heritage Site in Nigeria

The UNESCO World Heritage Sites have special conservation regulations because they are recognized as having significant cultural and/or natural value. One of Nigeria's two UNESCO-designated World Heritage Sites is the Osun River. It has immense biodiversity values, which are currently being threatened due to gold mining activities within its catchment area. Thus, this study seeks to ascertain the current biological water quality of this culturally and internationally important river using ecological and ecotoxicological approaches. Samples were collected from three environmental compartments (i.e., water, benthic sediment, and macroinvertebrates) in both dry and wet seasons from the section of the river that flows through the UNESCO site. Findings revealed that the river's physiochemical water quality has immensely degraded on account of extremely high total suspended solids, extremely low water transparency, and low dissolved oxygen. Three heavy metals exceeded their permissible limits in drinking water; i.e., Cd (364–367 times higher), Pb (75–104 times higher), and As (35–67 times higher). The contamination factor indicated that the benthic sediments were contaminated with Cd and Au, while the geo-accumulation (Igeo) index only indicates contamination on account of Cd, though Au ranks second in order of Igeo. The composition of the river's macroinvertebrate fauna suggests that it has been severely impacted because there was almost no stress-sensitive Ephemeroptera-Plecoptera-Trichoptera taxon present (one taxon and one individual only). Almost all of the chosen heavy metals had bioaccumulated in the three functional feeding guilds of macroinvertebrates. The current levels of heavy metals in the three environmental compartments of the river pose a great risk to both freshwater biodiversity and human health. Thus, a re-channeling of the upstream effluents from the river or any other natural water is advised. Also, a periodic environmental audit of the river should be conducted until it recovers from the pollution stress.

Sources, Toxicity, Health and Ecological Risks of Polycyclic Aromatic Hydrocarbons (PAHs) in the Sediment of an Osogbo Tourist River

ABSTRACT This study investigated twenty-three polycyclic aromatic hydrocarbons (PAHs) in the sediment of Osun River, spanning through both the peri-urban and urban areas of the river, to estimating their sources, ecological and health hazards. The sampling locations covered those beside major roads and agricultural farms. They were analyzed by gas chromatography-mass spectrometry. The concentrations of the PAHs ranged 88–1900 ng/g (average, 731 ng/g) with the predominance (56%) of benzo(e)pyrene (BeP). Though the PAHs had a similar trend of distribution in the sediment at both peri-urban and urban portions, total PAHs concentration at the peri-urban area was three times higher than that obtained in the urban area of the river due to relatively lower photo-degradation process caused by the thick rain forest in the area. Pyrolytic processes such as coal/wood burnings and emissions from gasoline and diesel engines were the PAHs sources. No dermal carcinogenic or non-carcinogenic health concerns were posed by the individual PAH; cancer risk and hazard quotient values were <10−6 and <1.0, respectively. The sediment PAHs posed a low ecological risk in all the sampling locations as the mean effects range-median quotient of the individual USEPA priority PAHs was ≤0.04. The potential environmental toxicity of the priority PAHs showed that benzo(a)pyrene (BaP) and indeno[1,2,3-cd]pyrene (IDcdP) dominated, accounting for 37% and 44% of the total toxicity, respectively. The low health and ecological risks posed by the PAHs sediment became significant given the number of tourists Osun River attracts annually festival, as well as the effects on the river ecosystem.

Nutrients: B-Vitamin Content Methionine, Micronutrients and Oestrogen of Osun River: A River that Runs Southwestern Nigeria into the Atlantic Gulf of Guinea

Nutrients: B-Vitamin Content Methionine, Micronutrients and Oestrogen of Osun River: A River that Runs Southwestern Nigeria into the Atlantic Gulf of Guinea

Bioaccumulation of heavy metals in edible foods in Osun River

Heavy metals are present naturally in relatively low amounts in the earth’s crust. But there is an increased alarming rate over the years of heavy metals present in water bodies and in turn aquatic life which has resulted to food poisoning. Trace amounts of some heavy metals, such as Manganese, calcium zinc, and potassium, are key to maintaining the metabolism of the human body but in high concentration could be considered as Metal pollution. Heavy metals can cause poisonings resulting in impaired mental and central nervous function, as well as damage to vital organs. Long-term exposure may result in slowly progressing physical, muscular, and neurological degenerative conditions including cancer. The Food and Drug Administration (FDA) enforces action levels for poisonous or deleterious substances in human food and animal feed, including cadmium, lead, mercury, and others from water bodies. Based on this report, Samples of edible foods such as fishes and crabs were obtained from five different locations in Osun River based on activities carried out daily. Results obtained proved that no heavy metal is present in edible foods at Osun river which makes it suitable and recommended for consumption.

Morphological differentiation in African catfish (Clarias gariepinus) from three different populations in Nigeria

AbstractIntraspecific morphological variation in Clarias gariepinus was studied in three water bodies. Twenty-three morphometric characteristics and seven meristic were used. Principal component (PC) analysis showed that morphometric traits of River Osun and Ogbese were somewhat related while that of Aago showed no relatedness, there were no difference among the meristic counts of the populations. PC1, and PC2 accounted for 93% and 4% of the variation observed in the populations. High positive correlation was observed in Aago (r = 0.872, b = 2.10) and Ogbese population while low correlation and negative allometric growth (r = 0.425 and b= 1.38) was observed in Asejire population. Cluster analysis revealed that three studied populations are separated into two major clusters, with samples from Asejire and Ogbese population found within the same cluster but different sub- clusters, similarly some of samples from Aago were also within the same cluster while samples 10 were found on a separate and major cluster. The study confirms the variability among individual species within each population, indicates the presence of genetic diversity among the populations of C. gariepinus and the Pre-anal distance and dorsal fin ray count could be employed in the identification of populations of catfish.&#x0D; Key words: morphometric traits, meristic characters, populations, allometric

PROXIMATE ANALYSIS AND HEALTH RISK ASSESSMENT OF HEAVY METAL POLLUTANT OF WATER AND SEDIMENTS IN OSUN RIVER

There are thirty-five (35) metals with public health implications due to occupational or residential exposure; twenty-three (23) of these are called heavy elements or metals. They are Antimony, Arsenic, Bismuth, Cadmium, Cerium, Chromium, Cobalt, Copper, Gallium, Gold, Iron, Lead, Manganese, Mercury, Nickel, Platinum, Silver, Tellurium, Thallium, Tin, Uranium, Vanadium, and Zinc. Interestingly, minute amount of these elements are common in our environment and diet and are actually necessary for a balanced health, but increased consumption may cause acute or chronic toxicity (poisoning). Allergies are not uncommon and repeated long-term exposure to these metals such as Zinc, Lead, Chromium, Selenium, Nickel, Cobalt and Cadmium may cause cancer. The alarming perceived increase of these pollutants around the south-western regions of Nigeria have necessitated the need to evaluate water and sediment samples of Osun river, popularly known for its cultural practices and activities. The physicochemical properties of samples such as pH, TDS EC, Total Dissolved Solid (TDS), Conductivity, Total Hardness, Sodium, Potassium, Phosphate, Nitrate, Chloride were analyzed and result showed compliance with recommended WHO standards. Trace and heavy metal composition in water using standard methods indicates the presence of Calcium (5.11±0.04ppm), Magnesium (0.54±0.004ppm), Potassium (1.28±0.01ppm) and Iron (0.05±0.00ppm) while sediment sample contained high composition of Zinc (21.99±2.67ppm), Iron (261.6±2.00ppm) and Manganese (105.6+0.50ppm). Results obtained from proximate analysis of both water and sediment samples, shows that there are no heavy metals presence in Osun River that could pose a threat to public health. Rather, there are more minerals and nutrients in availability which implies that water sample lacks considerable pollutants and can be certified healthy for moderate consumption and domestic uses which is within permissible value limits of WHO standards.&#x0D; Ashaolu V. O. | Research Scholar, Department of Chemistry, LIFE, Loyola College, Chennai-600034

Estimation of Bed Load Transport in River Osun, South-Western of Nigeria Using Grain Size Distribution Data

Sediment transport rate depends on bed composition, flow hydraulics and sediment supply. There is a paucity of information on bedload transport in River Osun. In this study, bedload in River Osun was estimated using grain size distribution data to predict channel migration and mitigate flooding. Grab sampler was used to collect sediment samples at the sampling point across the river designated as T1-T4. Sieve analysis was carried out in triplicate on sediment from sampling points using standard methods. Discharge and cross-sectional area were measured between December 2017 and December 2018 at sampling stations using standard methods. The seasonal and bedload were estimated using standards equations. The percentage of bed material particles above 5mm and less than or equal to 2mm were 50 and 22.49%, respectively. The average median grain (d50) size was 2.4mm. The discharge and cross-sectional area across River Osun ranged (0.53-17.46) m3/s and (3.83-47.46) m2. The seasonal suspended and bedload across the river were (206.43×103 kg/annum) and 2,538.77×103(kg/annum), respectively. The estimated sediment load of River Osun could be useful in determining the dredging period at any point across the river where deposition of sediment could be monitored.

Food habit and ecological balance of fish species in Osun river, Nigeria

The food habit and ecological balance of fish species in Osun River were investigated for a period of 12 months (November 2017 to October 2018) with monthly sampling of water and fish species in the river. Fish were sampled using monofilament gill nets of mesh size between 25mm and 101mm. A total of 4544 individuals belonging to 19 species and 10 families were captured. They were grouped based on their feeding habits into herbivores, carnivores, and omnivores. Carnivores dominated the River (38.63%) with Cichlids being the most abundant family (95.10%) and Oreochromis niloticus the most abundant fish species (14.10%). The Forage - Carnivore ratio (F/C) for the dry, wet and combined season was 0.64, 0.34 and 0.48 respectively. T-test showed significant differences (P &lt; 0.05) between all the trophic groupings in relation to seasons. The mean values recorded across the sampling months were Temperature (18.70 oC ± 2.69), pH (7.10 ± 0.25) and Dissolved Oxygen (3.20 mg/L ± 0.54) while Ammonia (1.20 mg/L ± 0.18) was significantly different (P &lt; 0.05) across the months of study. For the sampling points, mean values recorded were Temperature (17.90 oC ± 0.31), pH (7.20 ± 0.12), Dissolved Oxygen (3.20 mg/L ± 0.27 mg/L) and Ammonia (0.10 mg/L ± 0.21). The abundance of carnivores is not desirable, and it is therefore essential to maintain the ratio of forage and carnivorous fish species in the river for conservation of fish species.