Tomato contains large amount of water which makes it more susceptible to spoilage by fungi. These fungi that spoil tomatoes produce mycotoxins that are detrimental to human health. This study was therefore carried out to isolate, characterize and identify the fungi associated with the spoilage of tomato fruits sold in Okpuno, Amaudo, Eke-Awka, Nodu and Amaikwo Markets in Awka, Nigeria. The average fungal counts ranged between 1.3 x 10 3 and 2.0 x 10 3 cfu/ml, while the fungal isolates were Aspergillus niger, Rhizopus stolonifer, Fusarium oxysporum, Saccharomyces cerevisiae, Alternaria alternata, Penicillium digitatum and Geotrichum candidum. The percentage occurrence of the isolates in the fruits from Eke Awka was the highest (32.73%) while that of the fruits from Nodu market was the least (12.73%). Aspergillus niger had the highest percentage occurrence (47.27%) in the fruits studied, with Saccharomyces cerevisiae and Geotrichum candidum having the lowest percentage occurrence (3.64%). Pathogenicity test result showed that Aspergillus niger also had the highest decay diameter of 30mm in the healthy tomato fruits while Geotrichum candidum had the lowest decay diameter. Proper handling and adequate storage facilities must therefore be employed to prolong the shelf life of tomato fruits.
Background: The people of Awka urban show an increasing trend of using well water resulting to unreliable and quality-compromised water supply. Aim: Effects of depth and seasons on the physicochemical and bacteriological quality of selected well water samples in Awka urban, Anambra State was conducted to determine their quality and suitability for domestic uses. A total of thirty shallow and deep well water samples were collected during the rainy and dry seasons. Methods: Physicochemical analysis was carried out using standard analytical methods. The total bacterial count was determined by dilution method. Results: Some of the physicochemical parameters (PH, dissolved oxygen, nitrate, cadmium, lead and arsenic) exceeded the World Health Organization maximum containment levels indicating that the samples were unfit for domestic uses. The bacterial counts ranged from 2.66 to 3.26 logcfu/ml during the rainy season and 2.54 to 3.20 logcfu/ml during the dry season. The total coliform counts also exceeded the W.H.O levels. Citrobacter freundii, Shigella flexneri, Serratia marcescens, Proteus vulgaris, Vibrio cholerae, Salmonella typhi, Pseudomonas aeruginosa, Escherichia coli and Bacillus subtilis were isolated during both seasons and identified using standard analytical procedures. The bacterium that had the highest frequency of occurrence during the rainy season was Citrobacter freundii (16.55%) while Salmonella typhi had the highest frequency of occurrence during the dry season (17.69%) respectively. Proteus vulgaris had the least frequency of occurrence 5.41% and 4.62% during the rainy and dry seasons respectively. The results were analyzed statistically using two-way analysis of variance. Higher bacterial counts were recorded in rainy season and shallow wells than dry season and deeper wells. Conclusion: The presence of these bacteria above admissible limits showed that the water lacked proper water management services and may be harmful to humans. There is therefore a need to monitor the well water quality by employing better sanitary practices and subjecting the waters through various forms of water treatments before use to help prevent disease outbreak.
Effluent is wastewater flowing out of a sewer which constitutes environmental problems ranging from long-term ecological damage to increased water-borne diseases. In Nigeria, palm kernel oil is extracted from oil palm fruits in oil mills and the effluent is discharged without treatment to the soil in the vicinity of such mills. The effluent-receiving soil has been observed not to support the growth of vegetation. Hence in this work, the impact of palm kernel oil mill effluent on the soil physicochemical characteristics and growth of tomato plant was determined and compared with the effluent discharge limit established by the Federal Environmental Protection Agency. Samples of untreated and treated effluent, untreated and treated effluent-polluted soil and unpolluted soil were used for the study. The physicochemical analysis was carried out using standard physicochemical methods. The physicochemical values of the untreated effluent, except the pH, which was acidic, were higher than those of the treated effluent. Most of the physicochemical values of the untreated effluent-polluted soil were higher than those of the treated effluent-polluted soil and the unpolluted soil. The tomato plant grown in the unpolluted soil had better growth characteristics and yielded more fruits than those grown in the treated effluent-polluted soil. In addition, the tomato plant grown in the untreated effluent-polluted soil showed the lowest growth characteristics and yielded no fruits due to its elevated level of heavy metals and total petroleum hydrocarbons. The study showed that the untreated palm kernel oil mill effluent had a negative impact on the soil's physicochemical and growth characteristics of the tomato plant. Therefore, the effluent must be adequately treated to remove hazardous substances before its discharge into the terrestrial environment.
Good quality water is indispensable to human and animal existence. Storage facilities are commonly used to ensure sufficient water, predominantly where piped water supply operates occasionally. Therefore, water samples from five boreholes were analyzed before and during storage for three weeks in household plastic containers using standard physicochemical methods. There was an increase in pH, temperature, electrical conductivity, total dissolved solids, total solids, turbidity, nitrates, phosphates, sulfates, alkalinity, copper, and lead and a decrease in dissolved oxygen, chlorides, total hardness, total acidity, zinc, cadmium, iron, and chromium. In contrast, the total suspended solids remained unchanged during storage. The physicochemical parameters were within the World Health Organization Standard for drinking water quality except for the pH, total acidity, cadmium, and lead levels during storage. This study showed that water storage for three weeks in plastic household containers adversely affected the physicochemical quality of the water. Therefore, water must not be stored for an extended period in plastic containers to avoid deterioration in its quality.
Aims: To assess the toxicities of some herbicides as individuals and in binary mixtures to Lysinibacillus fusiformis isolated from Oryzasativa plant using dehydrogenase activity as an endpoint. Study Design: The binary mixture consists of combination of any two herbicides selected from the three herbicides (drysate, weedcut and aminoforce) for the study The binary mixture ratios (%) were designed as: 50%:50%; 80%:20% and 20%:80% for the respective mixtures in the concentration range of 0 -10, 000 mg/L. Place and Duration of Study: Silver Press Laboratory, Owerri Nigeria between July, 2016 and August, 2019. Methodology: A laboratory scale study was carried on three toxicants using dehydrogenase inhibition test. The inhibition of dehydrogenase activity of the isolate by toxicant was calculated relative to the control. All the dose-response relationships of the individual toxicants and that of themixtures were described by logistic dose model and Weibullcum model parameter. Results: The results revealed that the median inhibitory concentrations (IC50) observed were 1,067.33 ± 36.68 mg/L for drysate; 2,180.00 ± 147.31 mg/L for weedcut and 4,550.00 ± 62.45 mg/L for aminoforce. Duncan tests indicated that the IC50 of the toxicants were significantly different from each other. Among the individual toxicants, the ascending toxicities ranking were aminoforce > weedcut > drysate. The responses of the test organism to the stresses of the toxicants were dose-dependent and the toxicants also progressively repressed the dehydrogenase activity as the concentration increased. All binary mixtures were strongly synergistic against the organism. Conclusion: Thus, the toxicity of individual compound and synergistic effects of the mixtures of the toxicants indicates potential deleterious effects of both the individual chemicals and their mixtures to the rhizobacteria of Oryza sativa plant.
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