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- ItemECOTOXICOLOGICAL STUDIES OF PESTICIDE FORMULATIONS ON SOIL SENTINEL'S MICROFLORA (NITROSOMONAS AND NITROBACTER SPP.) AND MESOFAUNA (EPHYRIODRILUS SPP.)(GLOBAL ENVIRONMENT & SOCIAL ASSOCIATION, 2023) Ernest Ikenna Atuanya; Wakili Tope AborisadeThe ecotoxicological effect of pesticide formulations at the concentration range of half of the normal field rate (0.5FR), normal field rate (FR), 2FR, 4FR and 8FR respectively on representative microflora and mesofauna soil sentinels was investigated. Inhibition effects over the 1, 2, 3 and 4 hr period of exposure in Winogradsky media were observed for microflora. Avoidance responses were observed for mesofauna in pesticide spiked soils after a 48 hr exposure period. Generally, there was a corresponding decrease in mesofauna population with increase in pesticide concentrations. The LC50 values after 4 hrs of exposure indicated that endosulfan (4.37 µg/l) and paraquat (10.02 µg/l) formulations had more toxic effect on Nitrosomonas sp. Cypermethrin and glyphosate showed more toxic effects on Nitrobacter sp. with LC50 values of 10.21 µg/l and 10.50 µg/l respectively. Ephyriodrilus spp. were observed to avoid all the pesticide treated soils at different concentrations as compared to pesticide free soils with less than 20 % observed in the soil spiked with 4FR and 8FR for endosulfan and cypermethrin and 8FR for glyphosate and paraquat. Pesticide formulation at the concentration above the recommended rate could adversely affect the soil organisms and affect their important ecological functions.
- ItemIsolation and Screening for Potential endosulfan-degrading bacteria from Soil(Dutse Journal of Pure and Applied Sciences, 2024) Aborisade, W. T.; Ajao, A. T.; Ntagbu, F. G.; Bale, S. IThe urgent need for sustainable management of persistent organic pollutants, due to their negative impact on the environment, is of great concern to environmental stakeholders. In this study, the potential endosulfan-degrading (PED) bacteria were screened and identified from fresh soil samples collected from the Teaching and Research farm of Kwara State University, Nigeria. The bacterial strains were isolated using enrichment techniques and characterized through morphological, biochemical, and molecular analyses. Their potential for endosulfan utilization was assessed in an endosulfan supplemented mineral salt medium. Three potential endosulfan-degrading (PED) bacterial strains isolated were Achromobacter xylosoxidans strain PED1, Pseudomonas alkylphenolica strain PED2, and Sphingomonas sp. Strain PED3 with the accession numbers MF973060, MF973061 and MF973062 respectively. The optical density (OD) values increased for all the isolates by the third day, and the highest OD values of 0.51 (PED1), 0.52 (PED2) and 0.59 (PED3) were recorded on the ninth day. The observed increase in population density of the isolates in the endosulfan-supplemented mineral salt medium suggests their capability to utilize the endosulfan compound. Further study is required to evaluate the suitability of these strains for bioremediation purposes.
- ItemAntimicrobial and Phytochemical Analyses of Sida acuta Leaf Extracts on Selected Wound Isolates(Fountain Journal of Natural and Applied Sciences, 2021) Jimoh, F. A., Aborisade, W. T., and Bamidele, A. A.Medicinal plants have been intensively screened for their bioactivity in order to treat various diseases in human. This study was performed to evaluate the antimicrobial and phytochemical properties of Sida acuta leaf extracts against selected wound microbes. The plant extracts were obtained sequentially using n-hexane, aqueous and acetone respectively in order of increasing polarity. The extracts were tested for their antimicrobial activities against Staphylococcus aureus, Candida albicans, Klebsiella pneumoniae, Enterococcus faecium, Acinetobacter baumannii, Salmonella typhi and Pseudomonas aeruginosa using agar-well diffusion method. The sensitivity of the test organisms to the extracts was represented by zones of inhibitions (mm) at different concentrations. There was corresponding increase in the zones of inhibitions (mm) on the test organisms as the concentration of the extracts increased from 64 mg/ml – 512 mg/ml. Among the plant extracts, the aqueous extract of Sida acuta leaf revealed significantly higher zones of inhibitions (mm) from 7.50±2.12 - 25.00±1.40 on all isolates. This was closely followed by the acetone extract while the n-hexane extract produced the lowest zones of inhibitions (mm) on all the test organisms except for Acinetobacter baumannii which has 9.80±0.42 at the concentration of 512 mg/ml. Results obtained on the phytochemical analyses of the aqueous and acetone extracts revealed the presence of tannins, saponins, alkaloids and flavonoids. Hence, the antimicrobial effects of Sida acuta leaf extracts has been revealed in this study, therefore its controlled use should be encouraged in the treatment of wounds and other infections caused by these microorganisms.
- ItemEffects of an organophosphate (glyphosate) and a quaternary ammonium (paraquat) herbicides formulation on soils’ culturable bacterial and fungal populations(International Research Journal of Biological Sciences, 2022) Aborisade, W. T.; Atuanya, E. I.Herbicides play significant roles in weed management and contribute immensely to increase in productivity in agronomy system. However, its continuous application could have some dire effect on non-target soil microbiota. Therefore, this study assessed the impact of glyphosate and paraquat herbicides on soil culturable bacterial and fungal population. The loamy composite soil samples of forest reserve, Owena, Ondo State, Nigeria were used for the experiment. Each of the herbicide formulation was applied at the concentration rates ranged from half of the field recommended rate (0.5FR), the recommended rate (FR), two, four, and eight times the recommended rate (2, 4 and 8) FR respectively. The treatments were replicated thrice and arranged in complete randomized design, while the untreated soil samples serve as control. The standard pour plate technique was used for the enumeration of bacterial and fungal colonies after 5, 10, 15, 20, 25, 30 and 35 days of exposure. The findings showed that the glyphosate pesticides formulation applied at concentration range of 0.5 to 2FR significant stimulate bacterial populations of the soil samples while the fungal populations was not affected at the same concentration. However, the treatments at higher doses (4FR and 8FR) significantly reduced the number of bacterial and fungal counts of the soil samples. For paraquat treated soils, the treatment rate below the double recommended field rate did not have any significant effect (p > 0.05) on both bacterial and fungal populations. While the increases in inhibitory effect were observed with corresponding increases in paraquat application rates in the soil samples.
- ItemEFFECTS OF AN ORGANOCHLORINE AND PYRETHROID PESTICIDE FORMULATION ON SOIL’S CULTURABLE MICROBIAL POPULATION(International Journal of Technical Research & Science, 2020) Aborisade, W. T.; Atuanya, E. I.Non-target effect of pesticide on soil organisms is an important area of ecotoxicology, due to their roles in ecosystem sustainability. Thus, the effects of an organochlorine (endosulfan) and a synthetic pyrethroid (cypermethrin) pesticide formulation on soils’ culturable microbial population were investigated. The study was carried out on loamy sand soil sample types collected from Ondo State, Forest Reserve, Owena, Nigeria. Pesticide application rates in the range of half of the normal field rate (0.5FR), the normal field rate (FR), two times the normal field rate (2FR), four times the normal field rate (4FR) and eight times the normal field rate (8FR) were applied to the soil microcosm design in the laboratory; while the untreated soil serve as control. The experiment set up was completely randomized in three replicates and soil samples were collected from each of the set up at 5 days interval over 35 days period of exposure for analysis. The pour plate technique was used for the enumeration of bacterial and fungal colonies on nutrient agar and potato dextrose agar respectively. The results indicated that both pesticides had effects on the population of bacterial and fungal counts of the soil samples with significant (p < 0.05) adverse effect observed at the treatment rate above the normal field application rate. At lower application rates (0.5FR, FR and 2FR), temporary inhibitory effect on bacterial and fungal population were observed. The progressive increase in inhibitory effect with corresponding increase in concentration of endosulfan and cypermethrin were noticed.