Analysis of nutrient loads, heavy metals and physicochemical properties of wastewater, wetland grass, and papaya samples: Gondar Malt factory, Ethiopia with global implication

Robust attention was brought to researchers due to deterioration of wastewater quality of lakes and reservoirs as major global concerns by industrial release. The uncontrolled releases of effluents impose serious impacts for both aquatic and terrestrial environments. In the current study, many parameters like nutrient loads, heavy metals and physicochemical properties of wastewater, wetland grass, and papaya samples were analysed. The investigated nutrients, alkalinity, and total hardness in fresh water samples were within the allowable limits except for phosphate in fresh wastewater and alkalinity in wastewater. The detected levels of heavy metals (mg/L) in wastewater samples were:- Cd (0.386-0.905), Cr (ND-0.074), Cu (0.064-0.096), Mn (0.184-1.528), Fe (0.167-4.636), Zn (0.175-0.333), and Pb (0.044-0.892) (mg/L). The studied metals in the wastewater sample, except Cd, Fe, and Pb were lower than the allowable limit. The level of heavy metals in the grass and papaya samples ranged from Cd (37.14-147.62), Cr (ND-8.82), Cu (3.14-8.33), Mn (2.89-85.46), Fe(5.0-65.15), Zn (3.44-36.84), and Pb (ND-60.36) (mg/kg). The detected metals were below the permissible limits, except Cd, Cr, and Pb. The findings of the physicochemical characteristics in wastewater samples were computed: pH (6.61-8.54), temperatures (21.63-26.57 °C), TDS (205.9-1896 mg/L), EC (359.9-3226.67 μs/cm), BOD (12.0-732.67 mg/L), COD (3.67-1691.33 mg/L). Except for temperature and pH, all levels in the wastewater were above the recommended limit for wastewater discharge by USEPA.

Biosynthesis, characterization and study of the application of silver nanoparticle for 4-nitrophenol reduction, and antimicrobial activities

Silver nanoparticles (AgNPs) were synthesized from Vigna unguiculata (L) Walp extracted leaves, and characterized. The UV-Visible spectrum showed a peak between 411 and 415 nm at the Plasmon absorbance of the AgNPs. TEM showed that the size of AgNPs ranged from 5 to 13 nm. It was spherical with an average size of 11.08 nm. The size of AgNPs was 7 ± 6 nm and disperse in water. The AgNPs effectively reduced 4-Nitrophenol (4-NP) to 4-aminophenol (4-AP) in the presence of NaBH4. The AgNPs exhibited a strong antioxidant and antibacterial activity against Gram-negative bacteria: Escherichia coli (E. coli) and Klebsiella pneumonia and Gram-positive: Bacillus pumilus and Staphylococcus aureus. The average zones of inhibition of AgNPs were: 29 mm for Staphylococcus aureus, 23 mm for Bacillus pumilus, 17 mm for Klebsiella pneumonia and 15 mm for Escherichia coli (E. coli). Thus, AgNPs has exhibted good antibacterial activity compared to antibiotics drug and 4-NP reduction.

Metal distribution and human health risk assessment in legumes crops (chickpea, lentils and peas) from Belesa districts, Ethiopia

Accumulation of heavy metals in food is a major concern for humans' health. This study was aimed at determining the levels of Cu, Fe, Mn, Ni and Zn in chickpea, lentil and pea samples and evaluating the health risk for consumers. The concentrations (in mg/kg) of Cu, Fe, Mn, Zn, and Ni were varied from 23.6-48, 67.7-132.3, 15-26.5, 37.6-68.2, and 25.5-33.3 in chickpea, 39.8-80.5, 116.1-180.5, 12.1-21.6, 36.4-57.2, and 25.4-34.1 for lentil and 32-64.2, 51.6-100.0, 6.3-15, 25.3-42.5, and 25.5-48.5 for peas, respectively. Pearson correlation verified that strong positive correlations were observed between Cu and Zn in lentils, Ni and Mn, Fe with Cu and Mn in peas. Target hazard quotients (THQ) except Ni in all samples, Cu in lentil and pea were < 1 and the hazard index (HI) values of all heavy metals were greater than 1, thus an appropriate strategy is required to reduce exposure to heavy metals.

Selective Determination of Norfloxacin in Pharmaceutical Formulations and Human Urine Samples Using Poly(8-aminonaphthaline-2-sulfonic Acid)-Modified Glassy Carbon Electrodes

In this study, a glassy carbon electrode was modified potentiodynamically with poly(8-aminonaphthaline-2-sulfonic acid) [poly(ANSA)/GCE] for the detection of norfloxacin (NFN) in tablet formulations and human urine samples. Improvement of the effective surface area of the modified electrode and decreased charge-transfer resistance confirmed surface modification of the GCE by a conductive poly(ANSA) film. The appearance of an oxidative peak without a reductive peak in the reverse scan direction showed the irreversibility of the electrochemical oxidation of NFN in both the bare GCE and poly(ANSA)/GCE. A better coefficient of determination for the peak current on the square root of the scan rate (R² = 0.99514) than the scan rate (R² = 0.97109), indicating the oxidation of NFN at the poly(ANSA)/GCE, was predominantly diffusion mass transport-controlled. Under optimized pH and square wave parameters, the voltammetric current response of NFN at the poly(ANSA)/GCE showed linear dependence on the concentration, ranging from 1.0 × 10^-8 to 4.0 × 10^-4 M with a limit of detection of 4.1 × 10^-10. The NFN level in the studied tablet brands was in the range of 90.30-103.3% of their labeled values. Recovery results in tablet and urine samples ranged from 98.35 to 101.20% and 97.75 to 99.60%, respectively, and interference recovery results were less than 2.13% error in the presence of ampicillin, chloroquine phosphate, and cloxacillin. The present method had a better performance for the determination of NFN in tablet formulations and urine samples as compared with recently reported voltammetric methods due to its requirement of a simple electrode modification step, which provides the least limit of detection and a reasonably wider linear dynamic range.

Levels of heavy metals in ginger (Zingiber officinale Roscoe) from selected districts of Central Gondar Zone, Ethiopia and associated health risk

In this study, we investigated the concentrations of Cd, Cr, Cu, Fe, Ni, Pb and Zn; and their associated health risks through consumption of ginger. After the ginger samples digested with a mixture of HNO₃ and HClO₄ at 200 °C for 2:00 h, the amount of metals were investigated by flame atomic absorption spectrometry (FAAS). Efficiency of the analytical measurement was validated on spiking the sample with standard solutions of metals and the recovery for all studied metals were ranged from 91.60% to 99.94%, which is in the acceptable range of validation. The mean concentrations (mg/kg) were ranged from 4.63 to 5.43 for Cd, 2.17 to 4.44 for Cr, 62.52 to 65.14 for Cu, 77.71 to 81.12 for Fe, 6.49–7.58 for Ni and 16.74–19.31 for Zn. However, the concentration of Pb was not detected. The estimated daily intake (EDI) values of all metals from all samples are substantially lower than their corresponding maximum tolerable daily intake (MTDI). Target hazardous quotient (THQ) values of all metals are lower than 1 in all the sampling sites, revealed that there are no health risks for the users due to the intake of these metals. The health index (HI) values were slightly higher than unity, which implying that there is significant health effects to the population from consuming ginger at the study.