Solventless Synthesis of Zinc Sulphide Nanoparticles from Zinc Bis(diethyldithiocarbamate) as a Single Source Precursor.

This study explores the synthesis of nanoparticles through the thermal decomposition of single-source precursors, a method gaining popularity due to its low cost, minimal environmental toxicity, rapidity, scalability, and the ability to form nanoparticles with few defects. Zinc ethyl carbamate was synthesized and characterized using 1H NMR and infrared spectroscopy. Its purity was confirmed through microelemental analysis and melting point determination. The melting point of the complex was determined to be 165 °C. The thermogravimetric analyses indicated a one-step decomposition of zinc ethyl carbamate with a decomposition onset of of 200 °C, yielding a stable ZnS residue. Further thermal decomposition led to the formation of wurtzite phase ZnS nanoparticles, as evidenced by XRD. SEM micrographs displayed mixed spherical, and cubic unevenly sized, polydispersed nanoparticles, while EDX revealed approximately a 1 : 1 Zn to S ratio. Estimated band gap from the Tauc's plot gave 3.93 eV and 3.42 eV for the nanoparticles synthesized at 300 and 400 °C respectively. The wide difference in the band gaps may be as a result of the larger particles observed at 400 °C and the deformations in the sample as observed in the SEM.

An analysis of the foremost issues with artisanal and small-scale gold mining from Ghana's perspective.

Ghana has abundant mineral reserves in many of its regions, and gold mining remains one of the country's main sources of revenue. Given Ghana's current position in the global gold market, this review provides insight into the ASGM sector to give an understanding of the pertinent issues in the sector and its role in the socio-economic development of the country. This review assesses the effects of ASGM operations in economic, social, health, and environmental contexts to raise awareness of issues related to ASGM. It evaluates the measures taken to lessen the consequences of ASGM and maintain the sector's long-term viability. This review considers the foremost issues, including continued Hg use in ASGM, recent use of cyanide in ASGM, pollution of water bodies, and toxic metal contamination. It takes into account sustainable measures and remedial techniques that Ghana has implemented to alleviate the negative effects and support best mining practices. The primary factors influencing people to participate in ASGM are the need for quick sources of income, the scarcity of jobs in rural areas, the economic hardship, the need to supplement earnings from other activities like trading, and the comparatively meager profits from agricultural activities. Findings indicated that to gain more traction in addressing the challenges in the ASGM sector, the involvement of the community and direct stakeholders is essential to promoting responsible mining and environmentally sustainable practices. This review will increase awareness and pressure on decision-makers, researchers, and ASGM communities about the relevance of environmental conservation and sustainability.

Multivariate studies and heavy metal pollution in soil from gold mining area.

Mining generates large volumes of waste, which if not regulated can release toxic metals, causing widespread environmental contamination. This study focused on heavy metal contamination in topsoil within a mining area at Nangodi in the Northern Region of Ghana. A total of 24 soil samples were collected from the study area and control samples were analyzed for Hg, Pb, Cd, As, Cr, and Fe using atomic absorption spectroscopy. Results of Pollution Index estimations and Geo-accumulation index (Igeo) classified the soil samples as moderately contaminated to heavily contaminated. Soil samples were severely enriched with As and moderately enriched with b, and Hg. Multivariate analyses such as factor analysis and cluster analysis were employed to examine the relationship between the metals and also differentiate the influence of the natural background content of metals from that due to human activities. Factor analysis identified three polluted soil factor associations. Cadmium, Fe, As, and Pb associated with factor 1, were due to anthropogenic activities. The high intercorrelation revealed by As and Pb shows similarity in their sources. Factor two dominated by Hg is considered an anthropogenic component. Factor 3 correlated with Cr and can be considered a natural component. Correlation analysis and cluster analysis supported each other. Results from the bi-plots showed that sites S1, S8, S11, and S18, have similar metal composition as the control site. Heavy metal contents in soils sampled from Zones A and B have been influenced by the mining activities as seen from the associations of these sites in the bi-plots. The results are useful for metal source identification, and can contribute to monitoring and regulatory programs.

Exposure assessment and cancer risk characterization of aflatoxin M1 (AFM1) through ingestion of raw cow milk in southern Ghana.

Milk and dairy products are the most important nutritional foods among all age groups. Aflatoxin M1 (AFM1) contaminates milk and makes its consumption potentially dangerous. Infants are mostly at risk because they are typically fed as many as six and more times per day, which is indeed a disquieting concern. This study aimed at evaluating AFM1 levels especially above international (European Food Safety Authority, EFSA) (0.05 µg/kg) and local (Ghana Standards Authority, GSA) (0.5 µg/kg) standards and cancer risks associated with the ingestion of raw cow milk (n = 120) sampled from Southern Ghana (Greater Accra, Volta, Western and Eastern Regions). AFM1 were measured with High-Performance Liquid Chromatography with a Fluorescence Detector (HPLC-FLD). Risk assessments were also conducted using models prescribed by the Joint FAO/WHO Expert Committee on Additives (JECFA). Out of the 120 samples analyzed for AFM1, 67 (55.8%) tested positive, 63 (52.5%) exceeded the limits of EFSA and were between the range 0.06 ± 0.001-3.52 ± 0.5 µg/kg whereas 50(41.7%) within the range of 0.50 ± 0.03-3.52.01 ± 0.5 µg/kg exceeded GSA limits. Risk assessments of AFM1 for infants, toddlers, children, adolescents, and adults ranged between 0.06 and 2.03 ng/kg bw/day, 197.04-6666.67, 0-0.0323 ng aflatoxins/kg bw/day and 1.94 × 10-3- 0.07 cases/100,000 person/yr respectively for Estimated Daily Intake (EDI), Margin of Exposure (MOE), Average Potency, and Cancer Risks. It was concluded that the consumption of raw milk posed adverse health effects on all age categories studied for the regions investigated. The use of raw cow milk may cause some problems and endanger the health of people of different age groups due to noncompliance with prescribed regulatory limits.

Assessment of ameliorative effects of organic dietary interventions on neonicotinoid exposure rates in a Japanese population.

Neonicotinoid insecticides (NNIs) are a popular class of insecticides used in various pest management regimens worldwide. Biomonitoring studies continuously report high exposure rates of NNIs in various human populations across the globe. Yet, there is no validated countermeasure for combating the recent exponential rise in NNI exposure rates observed in human populations. The current study assessed the impacts of organic dietary interventions on NNI exposure rates in a Japanese population. A total of 103 volunteers were recruited into the study. Subjects were either served with Organic diets for 5 and 30 days or conventional diets. A total of 919 repeated urine samples were collected from the participants and then subjected to LC-MS/MS analysis to determine urinary concentrations of 7 NNIs parent compounds and an NNI metabolite. Eight NNIs were detected; with a decreasing detection frequency (%Dfs) pattern; desmethyl-acetamiprid (dm-ACE) (64.96%) > dinotefuran (52.12%), imidacloprid (39.61%) > clothianidin (33.95%) > thiamethoxam (28.51%) > acetamiprid (12.62%) > nitenpyram (5.33%) > thiacloprid (2.83%). Dinotefuran, dm-ACE, and clothianidin recorded the highest concentrations in the subjects. The %Df of NNIs in the 5-days or 30-days organic diet group were lower than those of the conventional diet consumers. The organic diet group showed lower rates of multiple NNI exposures than those of the conventional diet consumers. The mean and median cumulative levels of NNIs (median IMIeq) were significantly lower in the organic diet group than the conventional diet group (p < 0.0001). The estimated daily intakes (EDIs) of NNIs were higher in adults than children, but less than 1% of NNI cRfDs, except for clothianidin, which exhibited a %cRfD of 1.32 in children. Compared to the conventional diet group, the 5- and 30-day organic dietary intervention showed drastic reductions in NNI EDIs. Findings from the present study give credence to organic dietary interventions as potential ameliorative strategies for NNI exposure rates in human populations.

N-alkylimidazole derivatives as potential inhibitors of quorum sensing in Pseudomonas aeruginosa.

Antimicrobial resistance is a threat to global public health. Microbial resistance is mediated by biofilm formation and virulence behavior during infection. Quorum sensing (QS), a cell-to-cell communication is frequently used by microbes to evade host immune systems. Inhibiting QS channels is a potential route to halt microbial activities and eliminate them. Imidazole has been shown to be a potent warhead in various antimicrobial agents. This study aims to evaluate alkyl-imidazole derivatives as potential inhibitors of QS and to explore the interactions of the compounds with LasR, a key protein in the QS machinery of Pseudomonas aeruginosa. The study revealed that imidazole derivatives with longer alkyl chains possessed better antimicrobial activities. Octylimidazole and decylimidazole emerged as compounds with better anti-virulence and biofilm inhibition properties while hexylimidazole showed the best inhibitory activity against Pseudomonas aeruginosa PAO1. The binding affinity of the compounds with LasR followed a similar trend as that observed in the QS inhibitory assays, suggesting that interaction with LasR may be important for QS inhibition.

Optimization of extraction conditions for polyphenols from the stem bark of Funtumia elastica (Funtum) utilizing response surface methodology.

BACKGROUND: The recovery of phenolic compounds is seen as an arduous task because phenolic compounds are available as free aglycones, as sugar or ester conjugates, or as polymers with several monomeric components. This study looks at the optimization of factors that affect the efficiency for the extraction of phenolic compounds from the stem-bark of Funtumia elastica. METHODS: Five independent variables (solvent concentration, time, the temperature, solid-liquid ratio, and pH) of the extraction process were selected. Single factor analysis as well as the response surface method was used to evaluate the impact of the selected factors on the total phenolic content. The effect of the extraction factors on the phenolic content was tested for its statistical significant (p <0.05). For the response surface method, a five/factor, five/level central composite design was used, and a fitted second-order polynomial regression model equation was used to show how the extraction parameters affected the total phenolic recovery. RESULTS: The predicted value (R² of 0.5917) agreed with the adjusted value (R² of 0.7707). The residuals for response predictions were less than 5%. The optimal factors for the extraction were ethanol concentration of 75.99% v/v, extraction time of 193.86 minutes, temperature of 63.66°C, pH of 5.62, and solid-liquid ratio of 1:21.12 g/mL. Actual overall content of the phenolic compounds was validated at 82.83 ± 3.335 mg gallic acid equivalent (GAE) /g weight of extract, which agreed with the predicted response of 89.467 mg GAE/g of the dried extract under the optimal factors. CONCLUSIONS: The rich phenolic content of stem-bark of Funtumia elastica points to its potential as a functional medicinal product to alleviate diseases caused by oxidative stress such as asthma, breathing disorders, inflammation, and cardiovascular diseases. The results obtained indicate that, the studied optimal conditions support effective phenolics extraction of Funtumia elastica.

Heavy metal pollution and the role of inorganic nanomaterials in environmental remediation.

Contamination of water and soil with toxic heavy metals is a major threat to human health. Although extensive work has been performed on reporting heavy metal pollutions globally, there are limited review articles on addressing this pernicious phenomenon. This paper reviews inorganic nanoparticles and provides a framework for their qualities required as good nanoadsorbents for efficient removal of heavy metals from water. Different inorganic nanoparticles including metals, metal oxides and metal sulfides nanoparticles have been applied as nanoadsorbents to successfully treat water with high contaminations of heavy metals at concentrations greater than 100 mg l-1, achieving high adsorption capacities up to 3449 mg g-1. It has been identified that the synthesis method, selectivity, stability, regeneration and reusability, and adsorbent separation from solution are critical parameters in deciding on the quality of inorganic nanoadsorbents. Surface functionalized nanoadsorbents were found to possess high selectivity and capacity for heavy metals removal from water even at a very low adsorbent dosage of less than 2 g l-1, which makes them better than conventional adsorbents in environmental remediation.

Health risk assessment and levels of toxic metals in fishes (Oreochromis noliticus and Clarias anguillaris) from Ankobrah and Pra basins: Impact of illegal mining activities on food safety.

Arsenic (As), mercury (Hg), Cadmium (Cd) and lead (Pb) are toxic heavy metals that naturally occur in the ecosystem. Their levels are on the rise due to anthropogenic activities posing threat to aquatic wildlife and humans. In Ghana, pollution of some water bodies has led to unsafe consumption of riverine fishes as well as a shortage of treated potable water principally because the cost of treating polluted water has become expensive across the country. This study aimed to assess the As, Hg, Pb and Cd concentrations in water and fishes from rivers Pra and Ankobrah where activities of artisanal gold mining were carried out resulting in gross pollution of the water bodies. An experimental study was performed to ascertain the levels of As, Hg, Pb and Cd in fish species of Nile tilapia (Oreochromis noliticus) and mudfish (Clarias anguillaris) and aquatic media (water) from the Pra and River Ankobrah basins using the Atomic Absorption Spectrophotometer (AAS) (Varian AA240FS). Both river water samples recorded ranges of 0- 0.0040, 0.0060- 0.0387, 0 - 0.0020, 0.006-0.0093 mg/l for Cadmium, Lead, Arsenic and Mercury respectively. For Cadmium and Arsenic, their levels were comparable (p > 0.05). However, detected values for Lead and Mercury were no comparable (p < 0.05). Toxic metals concentrations in the rivers decreased in the order of Hg > Pb > Cd > As. For the fish samples, values ranged 0-0.08, 0.04-0.42, 0-0.04, and 0.40- 0.60 mg/kg for Cadmium, Lead, Arsenic and Mercury respectively. Generally, appreciably high values were obtained for Mercury. Toxic metals concentrations in the rivers decreased in the order of Hg > Pb > Cd > As. Human health risk assessment from heavy metal exposure through fish consumption from the Rivers for both children and adults showed no significant non-carcinogenic adverse health risk to humans since all calculated values for Hazard Quotient (HQ) were <1. Nonetheless, Target Hazard Quotient (THQ) values calculated for children and adult exposure to Cadmium and Mercury were>1 which implied a likely cause of adverse effects during a person's lifetime.

Potential health risk assessment of toxic metals contamination in clay eaten as pica (geophagia) among pregnant women of Ho in the Volta Region of Ghana.

INTRODUCTION: Geophagia although pleasurable and somewhat a necessity among pregnant women, also comes along with its own attendant problems such as exposure to potentially hazardous substances like bacteria, fungi, helminthes and ova, radioactive materials, and toxic elemental minerals in the soil depending on the geographical location. METHODOLOGY: This study evaluated the potential health risk involved during the exposure of pregnant women to toxic elemental minerals via the consumption of clay as pica (geophagia). Elemental mineral analysis was carried out using Buck Scientific 210VGP Flame Atomic Absorption Spectrophotometer (Buck Scientific, Inc. East Norwalk, USA). Risk assessment methods were also used to ascertain the various risks factors and the overall risk level. RESULTS: Concentrations of the macro elements investigated were 1.38 ± 1.5, 2.40 ± 1.5, 7.74 ± 1.5, 4.01 ± 1.0, 13.24 ± 2.2 and 13.76 ± 2.1 mg/Kg for iron (Fe), copper (Cu), zinc (Zn), potassium (K), magnesium (Mg) and sodium (Na) respectively. While that for the micro elements were 1.63 ± 0.03 µg/Kg, 4.72 ± 0.8, 0.53 ± 0.02 and 1.85 ± 0.3 mg/kg respectively for arsenic (As), manganese (Mn), lead (Pb) and nickel (Ni). Estimated Daily Intake (EDI), Hazard Quotient (HQ), Target Hazard Quotient (THQ) and Total Target Hazard Quotient (TTHQ) values ranged 0.611-5.44 (mg/kg Bw/day), 6.26 × 10- 4 - 106.5, 0.067-10.34 and 15 respectively. CONCLUSION: There is the likelihood of posing adverse health problems when clay samples obtained from Anfoega which is sited in the Volta region of Ghana is consumed due to the fact that the HQ's of these elemental minerals were > 1 which points to high content of Manganese (Mn) and Nickel (Ni). It is also likely to cause adverse health problems in an individual's life time since THQ for Arsenic, Lead and Nickel were above 1. Ultimately, the cumulative effect of these toxicants were exceedingly great (≤ 15) which implied a high level of unsafety associated with this clay. Per the results from this study, it is not safe for pregnant women to consume clay as pica since these toxic elements may cause detrimental effects on the foetus of the unborn child.

Risk Of Human Dietary Exposure To Organochlorine Pesticide Residues In Fruits From Ghana.

The objectives of this present study were to assess the level of organochlorine pesticide (OCP) residues in fruits and to determine the potential health risks associated with the exposure to these pesticides. A total of 120 fruits (watermelon, pineapple, and banana) were collected from five communities and a local market within the Mampong Municipality and analyzed for organochlorine pesticide residues. The results showed that the concentrations ranged from not detectable (ND)-48.22 ng/g for DDTs, ND-19.03 ng/g for HCHs, ND-4.10 ng/g for CHLs, ND-22.84 ng/g for Aldrin, and ND-11.53 ng/g for other OCPs. Levels of methoxychlor, Aldrin and gamma-hexachlorocyclohexane (HCH) exceeded the maximum residue limits in watermelon. Estimated health risk revealed that Aldrin in watermelon could pose potential toxicity to the consumer. Estimated average daily intake for Aldrin was above the acceptable average daily intake.

Single source molecular precursor routes to lead chalcogenides.

The use of single-source molecular precursors for lead chalcogenide thin films by CVD or as nanoparticles by solution methods is reviewed. The potential applications of these materials in solar energy are discussed along with the relative advantages of the various methods.

Levels of selected heavy metals in canned tomato paste sold in Ghana.

Sixty-one samples of canned tomato paste comprising seven brands originating from three countries and sold in local markets in the Kumasi Metropolis of Ghana were analysed for levels of iron (Fe), zinc (Zn), manganese (Mn), cadmium (Cd) and lead (Pb) by flame atomic absorption spectrophotometry and for levels of mercury (Hg) by direct mercury analyzer. Mean heavy metal concentrations varied by brand, ranging from below the limit of detection (Cd) to a maximum concentration range of 1.68 ± 1.63 to 58.6 ± 14.5 µg g⁻¹ (Fe). Estimated mean ranges of other heavy metals are 2.06 ± 0.62 to 8.52 ± 0.68 µg g⁻¹ (Zn), 2.62 ± 0.33 to 5.75 ± 0.47 µg g⁻¹ (Mn), 0.070 ± 0.003 to 0.116 ± 0.012 µg g⁻¹ (Pb) and 0.011 ± 0.001 to 0.102 ± 0.001 µg g⁻¹ (Hg). Assessed metal levels in five brands were below the WHO/FAO permissible levels. Results of the one-way analysis of variance (ANOVA) conducted on the data suggested no significant variations (P > 0.05) in the concentrations of the metals in the same brands of canned tomatoes.

Assessment of the quality of water from hand-dug wells in ghana.

This study focused upon the determination of physicochemical and microbial properties, including metals, selected anions and coliform bacteria in drinking water samples from hand-dug wells in the Kumasi metropolis of the Republic of Ghana. The purpose was to assess the quality of water from these sources. Ten different water samples were taken from different parts of Kumasi, the capital of the Ashanti region of Ghana and analyzed for physicochemical parameters including pH, electrical conductivity, total dissolved solids, alkalinity total hardness and coliform bacteria. Metals and anions analyzed were Ca, Mg, Fe, Mn, NO(3) (-), NO(2) (-), SO(4) (2-), PO(4) (2-), F(-) and Cl(-). Bacteria analysed were total coliform and Escherichia coli.THE DATA SHOWED VARIATION OF THE INVESTIGATED PARAMETERS IN SAMPLES AS FOLLOWS: pH, 6.30-0.70; conductivity (EC), 46-682 muS/cm; PO(4) (3-), 0.67-76.00 mg/L; F(-), 0.20-0.80 mg/L; NO(3) (-), 0-0.968 mg/L; NO(2) (-), 0-0.063 mg/L; SO(4) (2-), 3.0-07.0 mg/L; Fe, 0-1.2 mg/L; Mn, 0-0.018 mg/L. Total coliform and Escherichia coli were below the minimum detection limit (MDL) of 20 MPN per 100 ml in all the samples. The concentrations of most of the investigated parameters in the drinking water samples from Ashanti region were within the permissible limits of the World Health Organization drinking water quality guidelines.