Synthesis, Characterization and Antimicrobial Activity of Cu (II), Co (II) and Ni (II) Histidine Complexes

Ternary complexes of histidine amino acid (Schiff base) were synthesized, characterized and tested against multi-drug resistant pathogens. The metal ion centers included Cu (II), Ni (II) and Co (II). These complexes were characterized using physico-chemical and spectroscopic analytical methods. All the complexes are found to be considerably soluble in both polar and non-polar solvents including methanol, ethanol, butanol, acetone, ethyl acetate, and benzene and di ethyl-ether. Electronic Absorption Studies using FT-IR spectrophotometer revealed ν (O-H), ν (C=O), ν (C=N), ν (M -N) and ν (M-O) occurred between 3410 - 3417, 1751 - 1753, 1519 – 1521, 671 – 678, 439 – 470 cm-1 respectively in complexes and ligand. UV-Visible was further used to elucidate the complexes resulting in transitions characteristics of the ligand and complexes. The Schiff base showed no antimicrobial activity at various therapeutic concentrations. However, the metal complexes exhibited broad spectrum antibiotic activities against the multi-drug resistant pathogens at minimum inhibitory concentration (MIC ≤ 200 µg/ml). The metal complexes showed strong activity against the isolates at medium and high concentrations, the bacteria strains included E.coli, P. aeruginosa, S. typhi and S. aureus and the fungi strains of Candida albicans, Aspergillus flavus and Aspergillus niger. The bioactivity recorded against these multi drug resistant pathogens indicates the potentials of these complexes for further therapeutic studies. Keywords: Histidine complex, synthesis, characterisation, antimicrobial activity, pathogens

Characterization of formulated copper chitosan nanoparticles for the controlled release studies of dicamba dimethylamine herbicide

In this study, a dicamba herbicide was encapsulated onto copper nanoparticles (CuNPs) via a green chemical reduction method in order to improve its herbicidal activity, with the intention of reducing its negative impacts on the environment. The synthesised Dicamba-copper chitosan nanoparticles (Dic-CuCtsNPs) was characterised using UV-visible spectroscopy, scanning electron microscopy (SEM), Fourier transform- infrared (FT-IR), powder x-ray diffraction (PXRD), differential scanning calorimetry (DSC), thermo gravimetric analysis/differential thermal analysis (TGA/DTA) and energy-dispersive x-ray spectroscopy (EDX). The maximum absorption peak of the Dic-CuCtsNPs was observed at 556 nm. The encapsulation efficiency of the Dic-CuCtsNPs formulation was 86 %. The average crystalline size of the nanoparticles, from its PXRD pattern, estimated using the Debye- Scherrer’s equation was 45.94 nm. The SEM image obtained indicated particle size distribution of 16 – 64 nm. The DSC curve showed that the formulation exists in the crystalline state while the TGA data indicated that the formulation was thermally stable up to 425.75oC. Aqueous release study of Dic- CuCtsNPs was carried out using three different pH media and two agricultural soils. The leaching profile of the formulated nano-herbicide through the University of Agriculture (UAM) and college of advance and professional studies (CAPS) soil layer index showed a high value for the UAM soil being 43.84 % higher than in the CAPS soil value of 26.92 %. Thus, an eco-friendly herbicide delivery system was formulated using CuCtsNPs, for the successful release of Dicamba in aqueous medium and agricultural soils.Keywords: Controlled release, Dicamba, Encapsulation, Green synthesis, Herbicide, Soi

Analysis of Heavy Metals Contamination and Quality Parameters of Groundwater in Ihetutu, Ishiagu

The levels of some quality parameters and heavy metals in groundwater inIhetutu minefield of Ishiagu were analyzed in four seasons (rainy, late rainy,dry, and late dry), in order to evaluate the deterioration of the groundwaterqualities in the area. Pb-Zn mining and several other related activities havebeen going on for several decades in Ihetutu, and thus render the groundwater resources in the area less available for consumption, through toxic chemical substances expected to be constantly discharged to the groundwater bodies from the mines and other domestic wastes. The aim of this study was thus to determine the levels of heavy metals and other physico-chemical properties in the groundwater, to assess its suitability for drinking and other domestic purposes in Ihetutu. Samples were collected from dug-wells and underground water platforms, and analyzed using standard procedures, for their physico-chemical properties and heavy metals levels. Results obtained for the various seasons ranged as pH = 6.80-8.72, EC = 190.00-1120.00 µS/cm, alkalinity = 4.20-30.60 mg/L, TDS = 105.00-567.00 mg/L, TH = 8.00-44.00 mg/L, Cl- = 26.00-126.00 mg/L, Cu = 0.00-0.30 mg/L, Zn = 0.00-0.42 mg/L, Fe = 0.00-3.93 mg/L, Mn = 0.00-0.59 mg/L, and Pb = 0.00-0.43mg/L. Average levels of analyzed parameters in study area were: pH = 7.56,EC = 424.06 µS/cm, alkalinity = 17.88 mg/L, TDS = 218.69 mg/L, TH =21.88 mg/L, Cl- = 54.31 mg/L, Cu = 0.20 mg/L, Zn = 0.51 mg/L, Fe = 2.55mg/L, Mn = 0.32 mg/L, Pb = 0.38 mg/L. Mean levels of most parameters were found to be within standard guidelines/limits but were above control levels, giving an indication of deterioration of the groundwater qualities in the area. Also, seasonal concentrations of most parameters, including the heavy metals were in the order of LDS>DRS>LRS>RNS. Heavy metals mean concentrations also trended in the order of Fe>Zn>Pb>Mn>Cu. Correlations among heavy metals were all positive, with the strongest between Cu and Pb (r = 0.921) while the least was between Cu and Mn (r = 0.176).ANOVA showed no statistically significant differences among sampling stations in study area, as p-values (0.757) was higher than the significance level (α=0.05). Comparison of the results with control values, indicated cases of deterioration of the groundwater quality in the study area. This confirmed that the groundwater resources in the area were adversely affected by wastes and discharges from the mining activities and several other sources including domestic wastes

Preparation and Characterization of ‘Green’ Nano Silica from Rice Husks

Silica with Nanostructure is a high quality silica that is used in many industrial areas. The study was aimed at preparation and characterization of nanao silica from rice husk by precipitation method. The rice husk ash (RHA) was obtained by washing and burning rice husk (RH) at 700oC for 2 h in a muffle furnace. The RHA was subjected to Energy dispersive x-ray fluorescence (EDXRF) and silicon content was as high as 36.53 %. Indicating that there was silicon dioxide (silica) in RHA. Rice husk pure silica (RHS) was obtained by alkaline extraction method of 10g of RHA using 2.5 M sodium hydroxide. 9.3 g of RHS was obtained. The FT-IR spectral data which showed Absorption signals at 1069.7 cm-1, 957.97 cm-1, 797.7 cm-1 , 1632.6 cm-1  ,2885.0 – 3900 cm-1 and 2158.17 cm-1 , supported that the  substance produced is silica. The RHS was subjected to precipitation by refluxing silica with 6 M HCl and dissolving the substrate in 2.5 M NaOH by continuous stirring for 1 hour on a magnetic stirrer and then concentrated H2SO4 was added to adjust pH in the range of 7.5-8.5in order to produce nanosilica. The prepared Rice husk nano silica (RHNS) showed an X-ray diffractogram that has a strong broad peak at  18˚ to 36.5˚(2 ), which the absence of  sharp peak indicates that nanosilica prepared  is amorphous. FT-IR of RHNS support that the substance is silica. The SEM of the RHNS showed aggregates of silica forming fine globules of varied sizes. The EDXRF shows a complete removal of K from the RHA by alkaline treatment. Keywords: Rice husk, precipitation, EDXRF, FT-IR, SEM ,Rice husk nano silic

Comparative Assessment of Levels of Heavy Metals in Earthworm Casts and Soils at Contaminated Sites

ABSTRACT In this study, the levels of some metals in earthworm casts (EWC), surface organic matter (SOM) and the parent soil (PS) were compared to assess the bio-monitoring potential of earthworm casts. Samples of earthworm casts, surface organic matter (SOM) and the actual soil were collected from each of the randomly selected points (16) around an active dumpsite located at the North Bank Area of the River Benue in Makurdi, north-central Nigeria. The samples were assayed for Cd, Cu, Fe, Pb, Mn and Zn by flame atomic absorption spectrophotometry after aqua regia digestion. Results revealed that in the casts, metal concentrations (mg/kg) ranged as: Cd(

Phytoremediation and Bioconcentration of Mineral and Heavy metals in Zea mays Inter-planted with Striga hermonthica in Soils from Mechanic Village Wukari

Phytoremediation involves the use of plants to remediate contaminated sites. This study evaluates the effect of phytoremediation on mineral and heavy metal concentration in agricultural soil within the vicinity of mechanic village Wukari using Zea mays interplanted with Striga hermonthica (SMV-MS), Zea mays alone (SMV-M), Zea mays inter-planted with Striga hermonthica alongside the application of fertilizer (SMV-MSF) and Zea mays alone alongside fertilizer application (SMV-MF). The bioconcentration of mineral and heavy metal and their translocation factors from the root to shoot of maize plants were estimated using empirical models. The result reveals that the efficiency of phytoextraction of the mineral and heavy metals were within the range: P (3.12 – 44.71 %), K (16.89 – 96.32 %), Mg (0.013 – 94.12 %), Mn (2.31 – 99.98 %), Si (20.92 – 52.07 %), Zn (2.74 – 21.65 %), Pb (10.44 – 100 %), Cd (0.75 – 42.85 %), Fe (7.42 – 98.57 %) and Al (19.14 – 98.69 %) respectively. The mean root and shoot bioconcentration factors (BCFs) of K, Mg, Mn and Al were greater than one indicating higher accumulation of the elements in the root and shoot of the maize plants. The root BCF of the elements was generally in the order: Mn > K > Mg > Cd > S i > Al > P > Fe > Zn > Pb while the shoot BCF was in the order: Mn > K > Mg > Al > Fe > Cd > S i > P > Zn > Pb. The mean root to shoot translocation factors (TF) of P, Mn, Zn, Pb, Cd, Fe and Al were greater than one indicating effective translocation of the elements from the root to shoots. The translocation factors were generally in the order: Fe > Al > Pb > Mn > Zn > P > Cd > Mg > S i > K

Phytoremediation of heavy metal-contaminated sites: Eco-environmental concerns, field studies, sustainability issues and future prospects

Environmental contamination due to heavy metals (HMs) is of serious ecotoxicological concern worldwide because of their increasing use at industries. Due to non-biodegradable and persistent nature, HMs cause serious soil/water pollution and severe health hazards in living beings upon exposure. HMs can be genotoxic, carcinogenic, mutagenic, and teratogenic in nature even at low concentration. They may also act as endocrine disruptors and induce developmental as well as neurological disorders and thus, their removal from our natural environment is crucial for the rehabilitation of contaminated sites. To cope with HM pollution, phytoremediation has emerged as a low-cost and eco-sustainable solution to conventional physico-chemical cleanup methods that require high capital investment and labor alter soil properties and disturb soil microflora. Phytoremediation is a green technology wherein plants and associated microbes are used to remediate HM-contaminated sites to safeguard the environment and protect public health. Hence, in view of the above, the present paper aims to examine the feasibility of phytoremediation as a sustainable remediation technology for the management of metals-contaminated sites. Therefore, this paper provides an in-depth review on both the conventional and novel phytoremediation approaches, evaluate their efficacy to remove toxic metals from our natural environment, explore current scientific progresses, field experiences and sustainability issues and revise world over trends in phytoremediation research for its wider recognition and public acceptance as a sustainable remediation technology for the management of contaminated sites in 21st century

Atmospheric sources of trace element contamination in cultivated urban areas: A review

Producing food in cities has garnered increasing attention over the past decade. Although there are ecological and social benefits, cultivated urban areas (CUAs) also bear contamination hazards, including from trace elements (TEs). Trace element contamination has been studied extensively in CUAs, but atmospheric sources remain understudied and poorly understood. A brief discussion is offered on atmospheric particulate deposition processes in cities and their implications for urban food production. Available findings are discussed and contrasted. Existing research assesses atmospheric deposition indirectly or otherwise lacks controls for other TE contaminants. There is little to no engagement with methodological guidelines from the atmospheric sciences, which reduces confidence in the findings so far attained. Suggestions are delineated to combine techniques used in the atmospheric sciences with the robust methodologies already generated by studies on TE contamination in CUAs, such as isotope and TE ratios analyses

Green Synthesis of Copper Chitosan Nanoparticles for Controlled Release of Pendimethalin

Aim: In a bid to reduce the environmental impact from the use of herbicides, chitosan was used for the synthesis of copper nanoparticles and the controlled release formulations (CRFs) of pendimethalin copper-chitosan nanoparticles (Pend-CuCtsNPs). Methodology: The synthesized nanoparticles were characterized using UV-visible spectroscopy, Fourier Transform Infra-Red (FT-IR), Powder X-ray diffraction (PXRD), Transmission electron microscopy (TEM) and Energy-dispersive x-ray (EDX). Average crystalline size of the nanoparticles was estimated from the Debye- Scherrer’s equation. Results: The yield of the synthesized CuCtsNPs increased linearly with the weight of the starting material with percentage yield of 93.8% for the 0.8% chitosan matrix. Encapsulation efficiency of the nano-formulation fell within 57.5 and 92.7%. The aqueous release studies of Pend-CuCtsNPs, monitored for 96 hours in a batch release mode were carried out in three different pH media and percentage herbicide released for all composites showed that the release in pH 5.5 (acidic) medium was higher and the lowest release was recorded for pH 7.0 (neutral) medium. There was a statistically significant difference between pH groups and time as determined by UNIANOVA (p < .005). Conclusion: Findings from this study however shows that there is a controlled release of pendimethalin using nano-formulation over the conventional herbicide application