ChemSearch Journal

Distribution of heavy metals and potential human health risk in fish species from Komadugu River Basin, Yobe State, Nigeria

A. I. Mohammed — 2024-01-17

Fish samples (Clarias anguillaris, Synodontis budgetti and Heterotis niloticus) were collected during the rainy and dry season from Komadugu river basin, Yobe State, Nigeria and identified by a fisheries scientist for the determination of some heavy metals. The concentrations of heavy metals were determined using Atomic Absorption Spectroscopy (AAS) and X-Ray Fluorescence (XRF).Fish samples of uniform size and weight were collected and dissected to remove the flesh, liver, intestine and gills and prepared according to standard method. Heterotis niloticus were observed to show the highest total concentration of the heavy metals studied with a value of 2.19E+03 mg/kg, while Clarias anguillaris shows the lowest concentration with a value of 0.03 mg/kg. The accumulation of heavy metals in the tissues of fish samples were observed to be in the order of gills>liver>intestine>flesh in both methods. The concentrations of all heavy metals were significantly higher using XRF method when compared with AAS. Fe shows the highest average daily intake (ADI) value of 1.53E+00 mg/kg/day in Clarias anguillaris, while Synodontis budgetti shows the lowest value of ADI value of 8.23E-01 mg/kg/day among all the four species of fish samples studied. From the results obtained, the hazard quotient (HQ) values of some of the heavy metals in the fish samples during the rainy season were all above one (1). The lowest HQ value of 9.00E-08 in all the fish samples study was lower than 1, while the highest HQ of 1.50E+01 is greater than one (1). The highest and lowest cancer risks chances for the studied fish species were computed as 5.10E-02 and 5.40E-07 respectively. These risk values indicate that consumption of fish from the study area would result in an excess of 5 cancer cases per 1,000,000 people.

Synthesis and Study of Thermal Behaviour of Cu²⁺ and Fe²⁺ complexes derived from N-N¹-diphenylhydroxylamineethylacetate

M. S. Iorungwa — 2024-01-17

The Schiff base ligand N-N¹-diphenylhydroxylamineethylacetate (DHA) prepared by the reaction of 2-phenylglycinemethylesterhydrochloride and salicyaldehyde was used to precipitate the transition metal complexes of Cu²⁺ and Fe²⁺. These procedures were achieved using the microwave assisted technique regulated at 100^oC for 30 min. Characterization of the ligand and complexes was carried out on the basis of physical properties, FTIR, XRD, UV-vis, spectroscopy. Unit cell dimensions which were obtained from the XRD crystallography analysis agreed with the establishment of orthorhombic crystal structure. The spectroscopic studies showed bands assignable to the azomethine nitrogen coordinated to the metal ion. The thermal decomposition of the complexes indicates the loss of lattice water and decomposition of the ligands as key to the interpretation of successive weight loss.

Mechanical and water sorption properties of untreated footwear leather off-cuts (UFLO) reinforced waste high density polyethylene (wHDPE) composites for the production of boot-last

B. Habila — 2024-01-17

The utilization of waste polymers in footwear leather off-cuts fibre composites provides a useful material that is environmentally friendly. This work aimed at studying the mechanical and sorption properties of composites produced from wHDPE and UFLO. The matrix was waste high density polyethylene (wHDPE) and untreated footwear leather off-cut (UFLO) fibre as reinforcement. The composites were compounded using two roll melt mixing machine and compression moulding technique in the following weight percent of the fibre loading: 10%, 20%, 30%, 40% and 50% respectively. Subsequently, the mechanical and water sorption properties of the composites were analyzed. The results obtained indicated that, the tensile strength of the composites decreases as the fibre loads increases. The composites with 10 %wt fraction of the UFLO fibre recorded the highest strength of 19.11 MPa, while the lowest was obtained at 50 %wt fraction of the fibre. The highest impact energy of 4.5 J/mm² of the composites was recorded at 10 %wt fraction of the fibre. From the water sorption results, composite with 10 %wt fraction of UFLO fibre recorded the lowest water sorption properties of 0.78 % as compared to 20.27 % of the 50 %wt UFLO. Owing to the results obtained, these composites showed a promising mechanical and sorption properties for the production of boot-last as the tensile strength and water sorption of boot-last should not be less than 17.92 MPa 0.39 % and not more than 30.00 MPa and 11.57 % respectively.

Ecological risk assessment of heavy metal exposure to River Sauna as irrigation water source in Kano State, Nigeria

I. Surajo — 2024-01-17

The indiscriminate discharge of both domestic and wastewater have a great impact on the quality of water in River Sauna. This assess the quality of the water used for urban agriculture and ecological risk assessments of some heavy metals exposure in River Sauna as irrigation water source in Kano metropolis, Nigeria. Water samples were collected from different sites at distances of 0, 250, and 500 meters from points of discharge. The collected samples were analysed for physicochemical properties and heavy metals in the laboratory using standard methods. The results showed that amongst all the different sources evaluated, the industrial waste water had the highest pH, electrical conductivity and total dissolved solids of 8.26, 4.87 dSm^-1 and 2.89 gL^-1 respectively. Higher electrical conductivity (EC), residual sodium carbonate (RSC) and chlorides were observed both in industrial and domestic discharge sites. There is a high potential of salinity and environmental toxicity with the continued discharge of waste water from both industry and homes. The results also indicated a highly significant difference (P<.001) in the concentration of Ca, Mg and Na at varying distances within the sampling sites. The value of computed degree of contamination and pollution load index were observed to be <7 and <1 in all sampling sites respectively. The abundance of the heavy metals was in the order of Cu > Ni > Cd > Pb > Cr and below the WHO permissible limit for surface water, except for Cd, which recorded 0.015 mgl^-1 in the industrial discharge site and thus necessary treatments and precautions should be put in place to minimize the impacts.

Thermal stability profiling of Co(II), Mn(II), and Ni(II)-hydrazone based complexes: The role of kinetic and thermodynamics parameters

Iorungwa M. S. — 2024-01-17

The thermal stability of the ligands ( (E)–4- [(2 – (2, 4 – dinitrophenyl)hydrazono)methyl)phenol (L₁) and N- (4 – hydroxybenzaldehyde) – p - fluoroaniline (L₂) along their complexes of Co(II), Mn(II), and Ni(II) were profiled by thermo-gravimetric analysis (TGA), different thermal (kinetic and thermodynamics) parameters viz. Energy of activation (E_a), Entropy of activation (ΔS), Free energy of activation (ΔG), Enthalpy of activation (ΔH) and Frequency factor (A) were calculated using Freeman-Carroll’s and Horowitz-Metzger’s approximation methods. The thermal results of the ligands showed that they do not contain crystals of water while the complexes contain two molecules of water of hydration. The kinetic parameters revealed that, the decomposition reactions of the synthesized compounds followed first order reaction with the rate constant values ranging from 0.002-0.129 and the activation energies were 55.22, 76.59, 52.90, 52.88 and 75.23 kJmol^-1 for ( (E)–4- [(2 – (2, 4 – dinitrophenyl)hydrazono)methyl)phenol (L₁), N- (4 – hydroxybenzaldehyde) – p - fluoroaniline (L₂), Co(II), Mn(II) and Ni(II) complexes respectively which showed that, L₂ and Ni(II) complex requires extra energy to form activated complex as compared to L₁, Co(II) and Mn(II) complexes. On the other hand, the frequency factor acquired were 3.56, 5.06, 3.48, 3.50 and 4.97 min^-1 for L₁, L₂, Co(II), Mn(II) and Ni(II) complexes accordingly indicating that, more spaces existed in L₂ and Mn(II) complexes than L₁, Ni(II) and Co(II) complexes. Thermodynamics parameters results showed that, the Gibb’s free energy (ΔG) of the synthesized compounds were positive indicating that, the decomposition was non-spontaneous, The positive values of enthalpy (ΔH) showed that enthalpy is the driving force for the decomposition of the synthesized compounds and exothermic in nature. The negative values of entropy (ΔS) indicate the degree of disorder of the products formed by the dissociations of the bonds is lower than that of the initial reactants.

Cobaloxime complexes of diphenylglyoxime with aniline and substituted aniline: Synthesis and antimicrobial study

H. B. Adam — 2024-01-17

Five cobaloxime complexes represented as [Co(Hdpg)²(R)(SCN)] where H₂dpg is diphenylglyoximato, R = aniline (A), 4-bromoaniline (4BrA), 2-nitroaniline (2NA), 4-nitroaniline (4NA) or 4-anisidine (PA) have been synthesized and characterized by melting point, conductance measurement and infrared spectroscopy. The complexes were obtained in low yields (18 - 25 %) in the order 4BrA > 4NA > A > 2NA when the ligands interacted with cobalt(II) acetate tetrahydrate. However, [Co(Hdpg)²(A)(SCN)] was obtained in good yield (59 %). With the exception of [Co(Hdpg)²(PA)(SCN)]CH₃COO- which is 1:1 electrolyte, these complexes showed low conductivity values (35 – 54 Ω^-1cm²mol^-1), hence non-electrolytic in nature. Furthermore, they are of relatively low thermostability with melting points in the range (70 - 118⁰C). The results from IR spectroscopy indicated coordination of the cobalt ion via the nitrogen of the ligands. An octahedral coordination in which the central cobalt ion is surrounded by four nitrogen atoms of the two diphenylglyoximatemono anions from the equatorial positions and the other two sites occupied by atoms of monodentate neutral ligands and thiocyanate anion from the axial position was proposed. The evaluation of thein vitro antibacterial activity of the cobaloxime complexes were carried out against different strains of bacterial isolates including MRSA(Methiline Resistance Staphylococcus) Staphylococcus aureus, Bacillus subtilis, Streptococcus pneunoniae, and the Gram negative bacteria, Salmonella typhi, Klebsiella pneumoniae, escherichia coli, and Pseudomonas aeruginosa. The resultsrevealed that the zones of inhibition were only noticed in the case of Staphylococcus aureus and Salmonella typhi.

Facile synthesis and evaluation of Fe-Metal Organic Framework (Fe-MOF) as nutrient-slow-releasing agent

Kaana Asemave — 2024-01-17

Fe-Metal Organic Framework (MOF) was uniquely synthesized hydrothermally at mild conditions from ferric chloride, dipotassium hydrogen phosphate, urea, and oxalic acid (OXA) and duly characterised. The FTIR results showed that -OH of OXA; P-O of phosphate and C=O of OXA participated in the structural formation of the MOF. Whereas, NH₄⁺ and K⁺ were embedded into the layers of the MOF product. SEM result confirmed the image of the crystalline nature of the Fe-MOF at different magnifications with actual crystal size of 1.1 μm. The x-ray diffraction pattern gave major peaks as (110) and (111) corresponding to 200 at 28° and 31°, respectively implying the metal-carbonyl linkage for the MOF; as similarly observed in the FTIR absorptions. These results confirmed Face (111) and Body (110) Centered crystals (FCC and BCC).In the results of nutrient-slow-releasing capability of the iron-MOF, the trend of the release was: PO₄^3- (2.75 mg/L) < Fe³⁺ (3.30 mg/L) < NH₄⁺ (3.36 mg/L) < K⁺ (406 mg/L). Therefore, the synthesized MOF is recommended for real-life tests as slow-releasing fertilizer. The use of such products would also ensure food security, soil sustainability, and lessen pollution against the fast-releasing fertilizers. More so, the synthesis is handy and utilizes inexpensive reagents.

Zn(II) and Cd(II) complexes of cephalosporin: Solvent-free and solution-based syntheses, characterization and in vitro antimicrobial evaluation

Mohammed B. Fugu — 2024-01-17

Rapid increase of microbial resistance to antibiotics is fast becoming a global concern. To overcome this alarming problem, the discovery of novel active compounds against new targets is a matter of urgency. Herein, solvent-free and solution-based synthesized Zn(II) and Cd(II) complexes of cephalosporin derivatives (cefixime and cefuroxime) have been described and compared. The complexes were characterized by solubility, melting point and conductivity measurements, infrared spectroscopy, UV/Visible and metal analysis. The complexes were either milky, yellow or brown in colour and had high decomposition temperatures (187-315˚C). The complexes were all air stable and generally soluble in dimethyl sulfoxide but insoluble in n-hexane. The molar conductivity values (10.3 – 16.6 Scm² mol^-1) for both solvent-free and solution-based complexes were found to below indicative of the complexes being non-electrolytic. The coordination of the metal ions to the ligands occurred through oxygen of the three C═O in the ligands as it was evident from infrared spectroscopic analysis. The UV-Visible spectra for all the complexes formed showed a five-coordinate geometry around the ligands and two aqua molecules. In general, the characterization has evidenced the identical nature of the complexes obtained via the two synthesis techniques. The antimicrobial screening was carried out against four Gram-positive (Staphylococcus aureus, S. pyogen, Methicillin-resistance Staphylococcus aureus (MRSA) and Bacillus subtilis), four Gram-negative (Klebsiella pneumoniae, Escherichia coli, Salmonella typhi and Pseudomonas aeruginosa) bacteria and one fungus (Candida albicans). The results revealed that both ligands showed activity against all the micro-organisms tested except Pseudomonas aeruginosa and Streptococcus pyogene in the case of the ligand cefuroxime. Compared to the ligands, the other complexes were also more active against the micro-organisms. At all test concentrations, the complex [Cd(CFU)Cl²] showed increased activity against all tested micro-organisms. Similar results were reported for cefixime complexes which showed significantly enhanced antimicrobial and antifungal activities against microbial strains as compared to free ligand cefixime.

Determination of binary stability constant of the complexes of Ni(II) and Mn(II) ions with cysteine

Kaana Asemave — 2024-01-17

Conventional chelators have been reported to be toxic, non-biodegradable, and rigid towards the recovery of bonded metal ions. The drawbacks with these chelators necessitate a search for their alternatives such as amino acids. Therefore, binary complexes of biologically important transition metal ions; Ni(II) and Mn(II) with cysteine have been studied potentiometrically at about 27 ℃ in aqueous medium using Irving-Rossotti titration technique. The results obtained were used to evaluate the proton-ligand and metal-ligand stability constants. The proton-ligand stability constants were; log K₁H 8.4 (pKa for thiol group) and log K₂H 10.7 (pKa value for NH_2-group). The binary metal-ligand stability constant values for1:1 (M: L) complexes, log K as evaluated were found as Ni(II) > Mn(II); which is in agreement with the Irving–Williams order of the divalent metals of 3d series. Hence, these binary metal complexes could be applied as a medium of transporting chemotherapeutic drugs to target sites or detoxifying poisonous substances which possesses donor atoms with chelating capability. This finding also agreed with previous claimed that cysteine could be applied to transport metals to or away from target sites.

Chelate assisted phytoremediation of chromium from soil irrigated with municipal wastewater using Calotropis procera

D. Y. Lateefat — 2024-01-17

In this study, the efficiency of ethylenediamine tetraacetic acid (EDTA) and citric acid (CA) in the extraction of chromium (Cr) from soil irrigated with municipal wastewater using C. procera was investigated. The seeds of C. procera were planted in different pots containing 1kg of soil obtained from Lambun Sarki vegetable garden and irrigated with municipal wastewater. Five (5) ml of 0.1mmol EDTA and five (5) ml of 0.5mmol CA were added separately on the 10^th, 11^th and 12^th week. The control was setup the same way but without amendment. The plants were harvested after 13 weeks of planting and the average shoot heights of the plants were recorded. Cr contents in the roots and shoots of the plants in the control and chelate amended soils were analysed using microwave plasma atomic spectrophotometer (MP- AES). The results obtained showed that the individual application of EDTA and CA to the soil increased the average shoot heights of C. procera relative to the shoot height of control. The results obtained also showed that the application of EDTA and CA to the soil increased the accumulation of Cr in the plant tissues. Phytoextraction ability was assessed in terms of bioconcentration factor (BCF) and transfer factor (TF). The BCF values of C. procera for Cr increased with the application of EDTA and CA to the soil. The TF also increased with the application of EDTA and CA. The TF values showed that the removal of Cr by C. procera with EDTA and CA amendment was by phytoextraction.

Assessment of heavy metals and physicochemical parameters in fish and water samples in Sallari Pond, Tarauni Local Government Area, Kano State, Nigeria

Sholadoye Qazeem Oyeniyi — 2024-01-17

The present study was conducted to examine some physicochemical properties and heavy metal level in fish and water samples of Sallari pond, Kano State. The pH results ranged from 7.22 ±0.03 - 7.26 ±0. The conductivity results were all within the SON and WHO limits of 1000μs/cm except sample B (1233±0.00) which is above the limit. The results for turbidity ranged from (13.6 ± 0.01 - 15.00 ± 0.00) NTU, all the samples analyzed were within the SON and WHO limits of 5.0NTU. The result of the heavy metals in the water samples ranged from Zn (0.006±0.0001 - 0.011 ± 0.001) mg/l, Cd (0.00 ± 0.00 - 0.001±0.00) mg/l, Fe (0.03±0.01 - 0.16 ±0.01) mg/l, Cu (0.002 ± 0.00 - 0.0014±0.01) mg/l, Pb(0.0004±0.00 - 0.004±0.001) mg/l, Mn (0.0006±0.02 - 0.002±0.01) mg/l and Cr (0.00±0.00 - 0.002±0.001) mg/l. All the metal analyzed were within the SON and WHO limits of Zn(3.0), Cd(0.003), Fe(0.3), Cu (1.0), Pb (0.01), Mn (0.2) and Cr (0.05) mg/l respectively. The results for the fish samples ranged from Zn (27.20±0.00-545.60±0.01) mg/kg, Cd (3.20±0.01-51.20±0.03) mg/kg, Fe (30.40±0.05-6136.00±0.02) mg/kg, Cu (6.40±0.01-76.80±0.01) mg/kg, Pb (3.20±0.01-491.20±0.2) mg/kg, Mn (8.00±0.001-86.40±0.03) mg/kg and Cr (41.60±0.001-252.80±0.03) mg/kg. All the samples analyzed have their metal concentrations above FAO/WHO limits of Zn (40), Cd (0.1), Fe (100), Cu (30), Pb (0.4), Mn (1.0) and Cr(0.5)mg/kg. Also, the result for Bioconcentration Factor (BCF) shows that the entire metal studied have their BCF values above the USEPA Toxic Substance Control threshold limits of ≥ 5000mg/kg, which implies that the studied metals are very bioaccumulative in the fish samples and other aquatic animals in the pond.

Physicochemical and trace metals characterisation: An impact assessment of Badagry Creek on groundwater quality in Ojo Community, Lagos, Nigeria

A. O. Majolagbe — 2024-01-17

Groundwater is a major source of water supply with comparative advantages including convenient availability of water close to where it is required, and near excellent natural quality. However, groundwater quality is often compromised by various threats, both of natural and anthropogenic origins, including intrusion from big water bodies like seas. The aim of this study is to assess the possible impacts of Badagry creek on groundwater quality in Ojo community, Lagos. Fifteen (15) groundwater samples were collected from different hand-dug wells during both dry and wet seasons for physicochemical and some trace metal analyses using standard procedures. The physicochemical parameters analyzed included pH, electrical conductivity (EC), total dissolved solids (TDS), anions (NO₃^-, PO₄^3-, Cl^-), and some trace metals (Fe, Zn, Ca, Mg, Cu, Na, Pb, and K). Principal Component Analysis (PCA), Correlation Coefficient, and Cluster Analysis were applied on the data obtained. The concentrations of EC, TDS, and NO₃^-, were observed to be higher above World Health Organization (WHO) permissible limits, with values of 0.94, 0.81, and 2.92% respectively. Very strong correlation coefficient was observed between EC and TDS, Cl^-, and NO₃^-. Four principal components were extracted, and hierarchical dendrogram showed four (4) distinct clusters of wells. Iron and lead had mean concentrations above the WHO allowable limits which portends health risk. The quality of the groundwater investigated was questionable, especially with respect to high concentrations of NO₃^-, pointing at influence from the Badagry creek. Hence, there is need for regular monitoring, to ensure safety of man and sustainable environments.