Browsing by Author "Njau, Karoli N."

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    Antibiotic-resistant microbial populations in urban receiving waters and wastewaters from Tanzania
    (Elsevier, 2023) Ripanda, Asha Shabani; Rwiza, Mwemezi J.; Nyanza, Elias Charles; Miraji, Hossein; Bih, Numfor Linda; Mzula, Alexanda; Mwega, Elisa; Njau, Karoli N.; Vuai, Said Ali Hamad; Machunda, Revocatus L.
    Antimicrobial resistance against certain medications in the pathogenic microbial community is globally increasing due to the continual discharge and disposal of pharmaceuticals in the environment. The phenomenon resulted in significant antibiotic resistance among several exposed Enterobacteriaceae species, with wastewater treatment plants (WWTPs) and rivers serving as significant reservoirs. Despite antibiotic resistance being a tragedy, particularly in treating diseases by using antibiotics, local and regional studies indicating the severity, resistant species and the molecular level insight into these pathogens are scarce, thus requiring immediate intervention. This study, therefore, investigated wastewater from wastewater treatment ponds and receiving waters for the presence of resistant pathogens through phenotypical and molecular approach screening of their genes. Among the 57 analyzed samples, 18 (67%, n = 27) isolates of Klebsiella spp.., 4 (80%, n = 5) isolates of Proteus spp., 1 (100%, n = 1) of isolated Pseudomonas aeruginosa and 6 (18%, n = 34) of E. coli found were resistant to at least 1 among the tested antibiotics. E. coli had an 83% higher proportion of multi-drug resistance (MDR) than Klebsiella spp.., which had 68.5%, and no MDR was shown by P. aeruginosa isolates. Among the 20 bacterial isolates of antibiotic-resistant genes, showed that E. coli harboured 39%, followed by 22% of Klebsiella spp. Eleven (11) isolates of these 20 (55%) contained sulphonamides resistant genes: Sul 1 (n = 4) and Sul 2 (n = 7). Ten (10) isolates (50%) contained the tetracyclineresistant genes in which 4 isolates showed the Tet A, Tet B – 1 and 5 isolates contained Tet D. β-lactamases (bla CTX-M and bla SHV) were found in 7 isolates (35%). The existence of these antibiotic-resistant species in the urban receiving and wastewater presents a threat of transmission of diseases to humans and animals that are not cured by the existing medications, jeopardizing public health safety.
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    Data from the batch adsorption of ciprofloxacin and lamivudine from synthetic solution using jamun seed ( Syzygium cumini ) biochar: Response surface methodology (RSM) optimization
    (Elsevier, 2023) Ripanda, Asha; Rwiza, Mwemezi J.; Nyanza, Elias Charles; Bakari, Ramadhani; Miraji, Hossein; Njau, Karoli N.; Vuai, Said Ali Hamad; Machunda, Revocatus L.
    This dataset expresses the experimental data on the batch adsorption of ciprofloxacin and lamivudine from synthetic solution using jamun seed (JS) (Syzygium cumini) biochar. Independent variables including concentration of pollutants (10-500 ppm), contact time (30–300 min), adsorbent dosage (1-1000 mg), pH (1-14) and adsorbent calcination temperature (250,300, 600 and 750 °C) were studied and optimized using Response Surface Methodology (RSM). Empirical models were developed to predict the maximum removal efficiency of ciprofloxacin and lamivudine, and the results were compared with the experimental data. The removal of polutants was more influenced by concentration, followed by adsorbent dosagage, pH, and contact time and the maximum removal reached 90%.
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    Optimizing ciprofloxacin removal from water using jamun seed (Syzygium cumini) biochar: A sustainable approach for ecological protection
    (Elsevier BV, 2024) Ripanda, Asha; Rwiza, Mwemezi J.; Nyanza, Elias Charles; Bih, Linda Numph; Hossein, Miraji; Bakari, Ramadhani; Sigh, Somit Kumar; Reddy, Giridhar; Ravikumar, C.R.; Murthy, H.C. Ananda; Njau, Karoli N.; Vuai, Said Ali Hamad; Machunda, Revocatus L.
    Scientific interest in antimicrobial pollutants, such as ciprofloxacin, has increased. Due to spread of antibiotic-resistant bacteria, resistance genes, and their dissemination to the environment. Therefore, their remediation is necessary to ensure ecological sustainability. The current study aimed to optimise the removal of ciprofloxacin from synthetic water using jamun seed (JS) (Syzygium cumini) biochar using a response surface methodology (RSM). Result indicates ciprofloxacin elimination efficiency ranged between 32.46 and 94.95%, indicating the material can be improved and used for remediation of organics. The residual standard error of 4.4% were found for the predicted model, implying that the model is credible and can be used to predict future experimental findings. The R-squarred value for the improved Langmuir model's R2 is 0.9681 which is inclose agreement with the Freundlich isotherm, R2 0.9757. Therefore, JS biochar could be utilized for the remediation of ciprofloxacin from contaminated water and wastewater for ecological safety and sustainability.
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    Optimizing ciprofloxacin removal from water using jamun seed (Syzygium cumini) biochar: A sustainable approach for ecological protection
    (Elsevier BV, 2024) Ripanda, Asha; Rwiza, Mwemezi J.; Nyanza, Elias Charles; Bih, Linda Numph; Hossein, Miraji; Bakari, Ramadhani; Sigh, Somit Kumar; Reddy, Giridhar; Ravikumar, C.R.; Murthy, H.C. Ananda; Njau, Karoli N.; Vuai, Said Ali Hamad; Machunda, Revocatus L.
    Scientific interest in antimicrobial pollutants, such as ciprofloxacin, has increased. Due to spread of antibiotic-resistant bacteria, resistance genes, and their dissemination to the environment. Therefore, their remediation is necessary to ensure ecological sustainability. The current study aimed to optimise the removal of ciprofloxacin from synthetic water using jamun seed (JS) (Syzygium cumini) biochar using a response surface methodology (RSM). Result indicates ciprofloxacin elimination efficiency ranged between 32.46 and 94.95%, indicating the material can be improved and used for remediation of organics. The residual standard error of 4.4% were found for the predicted model, implying that the model is credible and can be used to predict future experimental findings. The R-squarred value for the improved Langmuir model's R2 is 0.9681 which is inclose agreement with the Freundlich isotherm, R2 0.9757. Therefore, JS biochar could be utilized for the remediation of ciprofloxacin from contaminated water and wastewater for ecological safety and sustainability.
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    Removal of lamivudine from synthetic solution using jamun seed (Syzygium cumini) biochar adsorbent
    (Elsevier, 2023) Ripanda, Asha; Rwiza, Mwemezi J.; Nyanza, Elias Charles; Bakari, Ramadhani; Miraji, Hossein; Njau, Karoli N.; Vuai, Said Ali Hamad; Machunda, Revocatus L.
    Antiviral drugs such as lamivudine have been globally identified in the environment and marked as emerging pollutants of concern due to their bioactive extremity. Following therapeutic uses, approximately 70% of the oral dose of lamivudine is eliminated renally as the parent drug. Concerns has been raised for neighbouring aquatic bodies due to effluent produced from production plants containing high concentrations of antiviral drugs. Antiviral drugs, such as lamivudine, are extremely bioactive, prompting interest in their urgent removal from the environment. The purpose of the present study was to optimize the removal of lamivudine from the synthetic solution using jamun seed (JS) (Syzygium cumini) biochar. The influence of sorption parameters such as pH, lamivudine concentration, adsorbent dosage, contact time, and calcination temperatures on the removal of lamivudine was investigated and optimized using a response surface methodology (SRM) based on optimal design. The results indicated that, a quadratic model best fits data with a model regression coefficient R2, adjusted R2, and predicted R2 of 0.9934, 0.9761 and 0.8340, respectively. The JS biochar calcined at 750°C, at pH 8, initial lamivudine concentration of 10 ppm and contact time of 30 min indicated a maximum experimental removal efficiency of 84.9%. The residual standard error (RSE) value was 3.5% implying that the model was reliable. Isotherm data for the adsorption of lamivudine on JS biochar followed the Freundlich isotherm, with an R2 value of 0.9977 while R2 for the modified Langmuir model was 0.9852. These findings indicated that JS biochar is potentially useful for removal of lamivudine, and other organics from contaminated water and wastewater effluents. Therefore, this study presents an environmentally friendly remedy against lamivudine for a healthier ecology
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    Removal of lamivudine from synthetic solution using jamun seed (Syzygium cumini) biochar adsorbent
    (Elsevier BV, 2023) Ripanda, Asha; Rwiza, Mwemezi J.; Nyanza, Elias Charles; Bakari, Ramadhani; Miraji, Hossein; Njau, Karoli N.; Vuai, Said Ali Hamad; Machunda, Revocatus L.
    Antiviral drugs such as lamivudine have been globally identified in the environment and marked as emerging pollutants of concern due to their bioactive extremity. Following therapeutic uses, approximately 70% of the oral dose of lamivudine is eliminated renally as the parent drug. Concerns has been raised for neighbouring aquatic bodies due to effluent produced from production plants containing high concentrations of antiviral drugs. Antiviral drugs, such as lamivudine, are extremely bioactive, prompting interest in their urgent removal from the environment. The purpose of the present study was to optimize the removal of lamivudine from the synthetic solution using jamun seed (JS) (Syzygium cumini) biochar. The influence of sorption parameters such as pH, lamivudine concentration, adsorbent dosage, contact time, and calcination temperatures on the removal of lamivudine was investigated and optimized using a response surface methodology (SRM) based on optimal design. The results indicated that, a quadratic model best fits data with a model regression coefficient R2, adjusted R2, and predicted R2 of 0.9934, 0.9761 and 0.8340, respectively. The JS biochar calcined at 750 °C, at pH 8, initial lamivudine concentration of 10 ppm and contact time of 30 min indicated a maximum experimental removal efficiency of 84.9%. The residual standard error (RSE) value was 3.5% implying that the model was reliable. Isotherm data for the adsorption of lamivudine on JS biochar followed the Freundlich isotherm, with an R2 value of 0.9977 while R2 for the modified Langmuir model was 0.9852. These findings indicated that JS biochar is potentially useful for removal of lamivudine, and other organics from contaminated water and wastewater effluents. Therefore, this study presents an environmentally friendly remedy against lamivudine for a healthier ecology.
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    A review on contaminants of emerging concern in the environment: a focus on active chemicals in sub-Saharan Africa
    (Scientific Research Publishing, Inc., 2022) Ripanda, Asha S.; Rwiza, Mwemezi Johaiven; Nyanza, Elias C.; Njau, Karoli N.; Vuai, Said A. H.; Machunda, Revocatus L.
    Active chemicals are among the contaminants of emerging concern that are rarely covered in regulatory documents in sub-Saharan Africa. These substances are neither in the list of routinely monitored substances nor in the guidelines for routine environmental monitoring activities. This has been of concern to public health officials, toxicologists, communities, and governments, hence the need for risk assessment and regulation of these substances. In this review article, the presence of active chemicals in the sub-Saharan African environment was investigated. The results indicate the availability of few studies in some countries, while in other countries no reports of active chemicals were found, hence the need for further research targeting such countries. It was further observed that mixtures of active chemicals from different therapeutic categories—such as antibiotics and analgesics—were reported. The natural environment is increasingly at risk due to the presence of these substances, their metabolites, and their transformation by products. These substances are characterized by persistence as a result of their non-biodegradable nature; hence, they circulate from one environmental compartment to another through the food chain, causing harm along the way. Most studies that evaluated the toxicity of these substances considered the effects of a single drug, but observations indicated the presence of drug mixtures, hence the need for further evaluation of the effects of drug–drug interactions—including synergistic and additive effects—for environmental sustainability. The presence of ACs in several environmental compartments at quantifiable quantities was discovered in this investigation, indicating the potential for ecosystem injury as a result of bioaccumulation, bioconcentration, and biomagnification through the food chain. This necessitates further research on the subject in order to ensure a healthier environment.