Microwave Plasma Atomic Emission Spectrometer Research Articles

Evaluation of selected minerals and health risk and proximate analysis of wasawasa (a street food)

This study was carried out to determine the proximate composition and the potential heavy metal health risk that may be associated with the consumption of wasawasa, a dish made from locally milled yam peels, by examining the presence of six metals (iron, nickel, chromium, sodium, and magnesium and potassium) in samples procured. Sixteen (16) samples of ready-to-eat wasawasa were collected from Aboabo, Manhyia, Sawaba, Asawase, Adenyase, and Ayigya in Kumasi, since these are the communities where wasawasa is mainly produced, sold, and consumed. The samples were digested with a nitric, perchloric, and sulfuric acid mixture and analyzed using a microwave plasma atomic emission spectrometer (Agilent 4210 MP-AES). The average concentrations of metals were Na (8506.88 mg/kg), Mg (222.63 mg/kg), Fe (84.45 mg/kg), Cr (2.31 mg/kg), K (1702.08 mg/kg, and Ni (1.12 mg/kg). Proximate analysis was used to determine Protein, fat, ash, moisture, and fiber content of the local wasawasa, which were found to be 15.667 %, 0.45 %, 1.00 %, 27.54 %, and 0.41 %, respectively. The hazard index of the heavy metals (Fe, Ni and Cr) for both adults and children were each greater than one, indicating the population is likely to experience non-carcinogenic effects from the consumption of wasawasa.

Removal of Arsenic from Contaminated Water by Polypyrrole-Based Adsorbents

Worldwide, there is growing concern over the toxicity of arsenic in drinking water. The US Environmental Protection Agency and Central Pollution Control Board (India) have set a safe limit of 50 parts per billion for arsenic in drinking water. Millions of people are at immediate risk due to high concentrations of arsenic in drinking water, particularly in developing nations where arsenic poisoning symptoms have been observed. One of the essential techniques described in this article is the absorption of arsenic from contaminated water by sustainable cellulosic materials like jute and wood sawdust after suitable modification. Jute and sawdust are cheap and abundantly available in South Asia. They are functionalized with polypyrrole coating by in situ chemical polymerization of pyrrole in aqueous medium in the presence of ferric chloride. Polypyrrole-coated jute fabric (with 11.28% polypyrrole add-on) and polypyrrole-coated sawdust (with 5.28% polypyrrole add-on) are found to be excellent adsorbers of arsenic ion (As3+) from water. The effect of dosage of polypyrrole-coated adsorbents, treatment time and pyrrole concentration on the As removal efficiency have been investigated in this work. The arsenic concentration in water is determined using a microwave plasma atomic emission spectrometer with the highest level of accuracy. Maximum As removal efficiency by the polypyrrole-coated sawdust and polypyrrole-coated jute fabric is found to be 80.90% and 97.3%, respectively, from a 50 mL, 7.5 parts per million As solution with a dosage of 1 g at neutral pH. The polypyrrole-coated jute and sawdust are characterized by Fourier-transform infrared spectroscopy to understand the chemical interaction between cellulose and polypyrrole molecules. The scanning electron microscope studies reveal a uniform coating of polypyrrole around the surface of jute fibre and sawdust particles. Thermo-gravimetric analysis shows good thermal stability of jute and sawdust after polypyrrole coating.

Investigation of Heavy Metal Composition and Associated Health Risks from Selected Groundwater Wells in Temeke, Dar-es-Salaam

Water quality continues to be the challenge to residents in Dar es Salaam due to various anthropogenic activities in the city. This study was conducted to assess groundwater quality by determining concentrations of heavy metals. Both probability and Nonprobability sampling techniques were used to collect samples from 40 groundwater wells in 24 wards of Temeke municipal and analysed using Microwave Plasma Atomic Emission Spectrometer (Agilent 4210 MP-AES) at the Geochemistry Laboratory of the University of Dar es Salaam. Results indicated varying heavy metal concentrations ranging from 0.71 ± 0.08 to 6.64 ± 0.21 mg/l for As, 0.02 ± 0.01 to 0.07 ± 0.01 mg/l for Co and 0.16 ± 0.01 to 0.02 ± 0.01 mg/l for Pb. The As, Co and Pb concentrations exceeded (P < 0.05) the recommended TBS standards of 0.05 mg/l, 0.003 mg/l and 0.01 mg/l respectively. Other concentrations ranged from 0.01 ± 0.01 to 0.88 ± 0.01 mg/l for Cu, 0.02 ± 0.01 to 3.55 ± 0.02 mg/l for Fe, 0.00 ± 0.00 to 4.63 ± 0.03 mg/l for Mn and 0.01 ± 0.01 to 3.00 ± 0.01 mg/l for Zn. The Cu, Fe, Mn and Zn concentrations were below (P > 0.05) the allowable TBS limits of 0.05 mg/l, 0.3 mg/l, 0.1 mg/l and 3 mg/l respectively. Health risk analysis revealed potential adverse health effects from long term consumption of As, Mn and Pb with Hazard Quotient exceeding 1 (HQ > 1). The Hazard Index (HI) for all groundwater samples was also above 1 (HI > 1) indicating a higher likelihood of adverse health effects. The study concluded that groundwater wells in Temeke Municipal are affected through natural and anthropogenic activities leading to high levels of heavy metal concentrations. Also, this study provides valuable information on risk associated by continued usage of groundwater in Temeke region and hence informs respective stakeholders on groundwater quality and potential risks thereby emphasizing the need for remedial measures and stricter regulations to safeguard public health. The study recommends the need for regular groundwater quality and safety monitoring to assess the levels of heavy metals concentrations and implement sustainable groundwater management strategies to address the increasing water demand in Temeke municipal, Dar es Salaam.

Nutritional composition and mineral bioavailability of selected root and tuber crops in the Bicol Region, Philippines

Filipinos consume root and tuber crops as inexpensive sources of nourishment. However, the limited information on the nutritional and mineral bioavailability of root and tuber crops inhibits their optimal utilization in what could possibly address nutrient deficiencies among the populations. This study determined the proximate composition of cassava, sweet potato, taro, giant swamp taro, cocoyam, and purple yam through the Association of the Analytical Chemists (AOAC) standard method. The mineral bioavailability was determined in vitro by simulating digestion from the oral up to the intestinal phase. Mineral and trace metal contents were quantified using a Microwave Plasma Atomic Emission Spectrometer (MP-AES). The crops’ ash, protein, fat, and total dietary fiber contents ranged from 1.23-3.53%, 2.01-9.32%, 0.18-0.83%, and 4.23-19.3%, respectively. Taro (9.32%) and purple yam (6.71%) have the highest protein contents among the crops examined and can be considered as sources of protein based on the recommended nutrient intake (RENI) for Filipino adults. Except for cassava, most of the studied crops were high sources of total dietary fiber, with the giant swamp taro (48% RENI) as the highest. Total minerals such as K, Ca, Mg, Na, and considerable quantities of Zn, Mn, Fe, and Cu were detected. The mineral bioavailability varied for Zn (47.0-98.0%), Cu (37.5-86.8%), Mn (31.5-91.8%), Mg (31.9-90.2%), Ca (2.54-31.1%) and Fe (4.7-20.7%). Consumption of 100 g of the examined crops, except for giant swamp taro and cassava, can contribute to the daily Cu for adults aged 19-29. Taro contributes to the daily nutritional requirement for bioavailable Ca and Mg, while giant swamp taro contributes to Zn and Mn requirements. None of the examined crops contained sufficient bioavailable Fe to contribute to Filipinos’ daily requirements. The study can help address the limited information on the nutritional and mineral bioavailability of root and tuber crops, which hampers their utilization to address some nutrient deficiency among the Filipino population, and emphasizes the consumption of these crops to enhance dietary diversification, which can alleviate some nutrient deficiencies in the country.

Effect of sodium chloride on yield, purity, morphology and polymorphs of calcium or magnesium carbonate sequentially precipitated from brine solution

Oilfield brine disposal in marine environments is undesirable due to concentrated salts of calcium, magnesium, sodium, and others which endanger aquatic organisms. Thus, it is paramount to precipitate the dissolved ions into stable carbonates for industrial applications. However, the effect of NaCl in the brine solution on the quantity and quality of precipitated carbonates is not yet reported. In this study, microwave plasma atomic emission spectrometer (MIP AES), x-ray diffraction (XRD), and scanning electron microscopy (SEM) were employed to investigate the effect of 0–2 M NaCl on the yield, purity, polymorph, and morphology of calcium and magnesium carbonates. The yields of 96.2% to 98.9% and 53.7% to 69.6% and the purity of 90.9% to 92.7% and 96% to 99.5% CaCO3 and MgCO3·3H2O were obtained, respectively. Moreover, the maximum yield and purity of carbonates were obtained from a brine solution of 1 M NaCl. The concentration of 0–0.5 M NaCl favored more the formation of aragonite whiskers and rhombohedral calcite whereas the concentration of 1–2 M NaCl favored more the formation of aragonite whiskers, lamella vaterite,and rhombohedral calcite. Nevertheless, only nesquehonite (MgCO3·3H2O) precipitated regardless of brine concentration. The crystal surface and length of the precipitated nesquehonite from 1 to 2 M NaCl brine were affected.

Assessment of trace elements (Cu, Fe, and Zn) in Limnothrissa miodon from Lake Kariba, Zambia: implications for ecological and human health

ABSTRACT This study examined Copper (Cu), Iron (Fe), and Zinc (Zn) levels in Limnothrissa miodon fish from Lake Kariba in Zambia and their potential impact on human health. Two-gram samples from each stratum underwent a 12-hour digestion, and concentrations were determined using Microwave Plasma Atomic Emission Spectrometer. Results indicated that Cu, Fe, and Zn concentrations fell within Food and Agricultural Organization and World Health Organization safety limits. Estimated Daily Intake (EDI) and Hazard Quotient (THQ) values for males and females remained under recommended thresholds, suggesting minimal health risks from consumption. Element concentrations followed the order Fe > Zn > Cu, all below Recommended Daily Allowances (RDAs). THQ values, with Zn posing the highest potential risk followed by Fe and Cu, were under one. Overall, the Hazard Index (HI) was 0.02, signifying a low non-carcinogenic risk from fish consumption. Despite safety, ongoing monitoring of heavy metal accumulation in the ecosystem is advisable for long-term safety. In conclusion, trace element levels in Limnothrissa miodon from Lake Kariba are safe for human consumption with low associated health risks. Nonetheless, continued monitoring of heavy metal levels is vital.

Contamination of selected heavy metals in Limnothrissa miodon (Boulenger, 1906) in the four strata of Lake Kariba Zambia: are the consumers at risk?

Pollution of aquatic ecosystems is one of the major challenges affecting many countries of the world. Heavy metal pollutants, in particular, threaten the life of aquatic organisms (fauna and flora) and, more importantly, humans who consume aquatic products as a critical source of proteins. In the present study, the concentrations of selected heavy metals (cobalt- Co, Chromium-Cr, nickel- Ni and manganese- Mn) in Limnothrissa miodon, locally known as ‘Kapenta’ were assessed using the Microwave Plasma Atomic Emission Spectrometer (MP AES) 4200 at the Zambia Agricultural Research Institute (ZARI). The fish was collected from Lake Kariba, Zambia, which is divided into four fisheries management strata (I, II, III, and IV). The health risks to consumers were evaluated using the Estimated Daily Intake (EDI), Target Hazard Quotient (THQ) and Hazard Index (HI). Analysis of variance (ANOVA) was used to assess the difference in the means of heavy metal concentration across the four strata for each element. The concentrations of all the heavy metal elements were within the permissible limits considered to be safe for human consumption based on the Food and Agriculture Organization (FAO) standards. However, the concentration of individual heavy metal elements varied significantly across the strata with stratum I and II showing higher levels in general except for Mn which was highest in stratum II and III compared with the other strata. Furthermore, Mn concentration was the highest in all the strata and the highest concentration was observed in the fish from stratum II. The EDIs, THQs and HIs of each heavy metal element did not show any threat to consumers of the fish from the lake. Further studies are required to better understand the potential sources of heavy metals and to regularly monitor existing activities that may elevate the concentration levels.

Mineral Status of Lactating Jaffarabadi Buffaloes in Their Home Tract: A Field Study

Deficit macro and micro-minerals in the ration of lactating Jaffarabadi buffaloes adversely affects growth, milk production and reproduction efficiency. For present study, four villages from each of 5 talukas were selected at random for taking representative samples of soil, feeds, forages and blood plasma of lactating Jaffarabadi buffaloes. Within the village, help was sought from village milk producers and district animal husbandry officer for identification of 3 farmers and collection of representative samples. All the samples were processed and analysed for chemical composition as well as major macro and micro-minerals, using Microwave Plasma Atomic Emission Spectrometer (MP-AES). Ca content was high in groundnut haulms (0.95%), but maize forage (0.23%), cotton seed cake (0.16%), cotton seed (0.12%) and maize cake (0.25) were found to be below the critical level (0.30%). The P content in concentrate ingredients was high (0.38-0.68%), but low in roughages (0.07-0.20%). Green jowar (0.18%) and maize cake (0.10%) were deficient in Mg. Feeds and forages were found to be adequate in iron. Abundant level of Cu was found in all feeds and forage. Sugarcane was found deficient in all minerals, except iron, and groundnut haulms (20.70 ppm) were found to be deficient in Zn. The blood mineral profile of the majority of lactating Jaffarabadi buffaloes was adequate. From the present study, it was apparent that soil and therefore forages cultivated in particular region were deficient in P and Zn. Same minerals were adequate in concentrate available in this area. So, to fulfil the requirement of deficient minerals there is need to feed concentrate along with area specific mineral mixture to the buffaloes.

A Comparative Study on Heavy Metal Removal from CCA-Treated Wood Waste by Yarrowia lipolytica: Effects of Metal Stress.

Bioremediation is an effective way to remove heavy metals from pollutants. This study investigated the effects of Yarrowia lipolytica (Y. lipolytica) on the bioremediation of chromated copper arsenate (CCA)-treated wood wastes. Copper ions stressed the yeast strains to improve their bioremediation efficiency. A comparison of changes in morphology, chemical composition, and metal content of CCA wood before and after bioremediation was conducted. The amount of arsenic (As), chromium (Cr), and copper (Cu) was quantified by microwave plasma atomic emission spectrometer. The results showed that yeast strains remained on the surface of CCA-treated wood after bioremediation. The morphologies of the strains changed from net to spherical because of the Cu2+ stress. Fourier-transform infrared spectroscopy showed that carboxylic acid groups of wood were released after removing heavy metals. A large amount of oxalic acid was observed when the optical density (OD600nm) was 0.05 on the 21st day. Meanwhile, the highest removal rate of Cu, As, and Cr was 82.8%, 68.3%, and 43.1%, respectively. Furthermore, the Cu removal from CCA-treated wood increased by about 20% after Cu2+ stress. This study showed that it is feasible to remove heavy metals from CCA-treated wood by Y. lipolytica without destroying the wood structure, especially by copper-induced Y. lipolytica.

Concentrations of Manganese in Tufted Titmouse Feathers near Metal Processing Plants

Human industry and land use has led to the anthropogenic release of manganese (Mn) into the air and soil near manufacturing centers. Overexposure to Mn can cause considerable health problems in birds. We studied whether the concentration of Mn in bird feathers correlates with the distance to point sources of Mn air emissions. Feathers were collected from Tufted Titmice (Baeolophus bicolor) at two sites in western Pennsylvania, USA. One site was in proximity (0.3 km) to a steel plant with documented Mn releases, and the other site was in a different town about 4.0 km away from other steel plants with documented Mn releases. Using the microwave plasma–atomic emission spectrometer (MP–AES), we found that tail feathers collected from nearest to a steel plant had a significantly higher concentration of Mn compared to the samples from the site further from the emission source. A body mass index was calculated for each set of birds; however, the indices did not vary significantly. This is the first published study of Mn sequestration in Tufted Titmouse feathers. This study develops our general understanding of the potential use of bird feathers as non-invasive bioindicators of environmental metal exposure.

Valorization of Bioactive Compounds from By-Products of Matricaria recutita White Ray Florets

In this research, we have reported the valorization possibilities of Matricaria recutita white ray florets using supercritical fluid extraction (SFE) with CO2. Experiments were conducted at temperatures of 35-55 °C and separation pressures of 5-9 MPa to evaluate their impact on the chemical composition and biological activity of the extracts. The total obtained extraction yields varied from 9.76 to 18.21 g 100 g-1 DW input. The greatest extraction yield obtained was at 9 MPa separation pressure and 55 °C in the separation tank. In all obtained extracts, the contents of total phenols, flavonoids, tannins, and sugars were determined. The influence of the supercritical CO2 extraction conditions on the extract antioxidant capacity was evaluated using the quenching activity of 2,2-diphenyl-1-picrylhydrazyl (DPPH). The chemical composition of the extracts was identified using both gas and liquid chromatography-mass spectrometry methods, whereas analyses of major and minor elements as well as heavy metals by microwave plasma atomic emission spectrometer were provided. Moreover, extracts were compared with respect to their antimicrobial activity, as well as the cytotoxicity and phototoxicity of the extracts. The results revealed a considerable diversity in the phytochemical classes among all extracts investigated in the present study and showed that the Matricaria recutita white ray floret by-product possesses cytotoxic and proliferation-reducing activity in immortalized cell lines, as well as antimicrobial activity. To the best of our knowledge, this is the first paper presenting such comprehensive data on the chemical profile, antioxidant properties, and biological properties of SFE derived from Matricaria recutita white ray florets. For the first time, these effects have been studied in processing by-products, and the results generated in this study provide valuable preconditions for further studies in specific test systems to fully elucidate the mechanisms of action and potential applications, such as potential use in cosmetic formulations.

Investigation of Pollution Level of Traces Metals Elements in Agricultural Soil of Oubritenga Province of Burkina Faso

The purpose of this study was to investigate the pollution level of trace metals As, Cd, Co, Cr, Cu, Hg, Mn, Ni, Pb, Sb, Se and Zn in agricultural soil around the water reservoir. A total of 36 soil samples were collected both during off-season agriculture and pluvial agriculture from April to October 2022. The samples were analyzed for trace metals according to the standard methods of the US EPA 2007 with a microwave plasma atomic emission spectrometer (MP-AES), Agilent Model 4210. The pollution level was assessed using contamination factor (Cf) and modified contamination degree (mCd). During the off-season, the concentration of trace metals followed in descending order as Mn > Cr > Cu > Pb > Zn. As, Cd, Co, Hg, Ni, Sb and Se were below the detectable limits. In pluvial season, the concentration of traces of metal follows the order Mn > Cr > Zn > Cu > Ni > Pb > Hg > As. Cd, Co, Sb and Se remain below the detectable limits. The concentrations of Cr, Mn and Zn were lower in the off-season agriculture than in pluvial agriculture. For Cu and Pb, the concentrations were higher in the off-season than in pluvial agriculture. The Cf ranges from 0.24 to 11.70 depending on the considered trace metal. The Cf values of As, Ni, Pb, Zn and Mn indicated that the agricultural study soil was lowery contaminated by these trace metals. The agricultural study soil was moderately contaminated by Cr and Cu, and highly contaminated by Hg. Globally the agricultural study soil presents a moderate degree of contamination (mCd 2.25) by the eight trace metals studied. This result provides information on understanding the risks of trace metal contamination of agricultural soil. It is important to anticipate the control of soil contamination through regular monitoring of toxic metals in agricultural soils, control the quality of chemicals used in agriculture and regulate their use.

A validated analytical method to measure metals dissolved in deep eutectic solvents.

This work presents the first validated method to analyze metals dissolved in deep eutectic solvents (DES) on a microwave plasma atomic emission spectrometer (MP-AES), which is key to the success of the upcoming field of solvometallurgical processing. The method was developed and validated for eleven metals: alkali metals: lithium (Li); alkaline earth metals: magnesium (Mg); transition metals: iron (Fe), cobalt (Co), nickel (Ni), copper (Cu), zinc (Zn), palladium (Pd); and post-transition metals: aluminum (Al), tin (Sn), and lead (Pb) in choline chloride based DES. The proposed method was validated with respect to linearity, limit of detection (LOD), limit of quantification (LOQ), accuracy, precision, and selectivity. Our method's selectivity was evaluated for three DES matrices: (1) choline chloride: ethylene glycol, (2) choline chloride: levulinic acid, and (3) choline chloride: ethylene glycol in the presence of iodine, which is an oxidant often used in solvometallurgy. In all three matrices, the linearity range was plotted with at least 5 levels of standard solutions. All the parameters satisfied the acceptability criteria suggested by international organizations, such as the International Council for Harmonization, AOAC International, and the International Union of Pure and Applied Chemistry. Specifically, the calculated LOD and LOQ are comparable with aqueous matrices on MP-AES and with other analytical methods. The metal with the lowest reported LOD (0.003 ppm) and LOQ (0.008 ppm) was Cu, while the highest LOD and LOQ were obtained for Mg at 0.07 and 0.22 ppm, respectively. The recovery and precision for the three DES matrices were acceptable, i.e., between 95.67-108.40% and less than 10%, respectively. Finally, to compare the proposed method with the standard analytical method used to measure metals dissolved in aqueous solutions, we used 2 ppm standard solutions in DES and found that the accuracy was unacceptable without using the proposed method. Therefore, it is evident that our method will be pivotal in the field of solvometallurgy, as it will allow accurate and precise detection and quantification of metals dissolved in DES and eliminate quantification errors, which were estimated in excess of 140% without using the method developed and proper DES matrix-matched calibrations.

Physico-chemical Properties and Heavy metal Contamination Levels of Soils from Riruwai Mining Area, North-western Nigeria

Mining activities, despite their economic importance, are well documented as one of the most significant sources of heavy metal pollution in the soil. In the present study, the physico-chemical properties and heavy metal contamination levels of the soils around the Riruwai mining area, in north-western Nigeria, were investigated. A total of 60 surface soil samples from four (4) sampling sites, which include 18 from active mine sites, 12 from abandoned mine sites, 21 from farmlands and 9 from control sites, were collected during the dry and rainy seasons. The physico-chemical properties such as pH, electrical conductivity (EC), soil organic matter (SOM), and cation exchange capacity (CEC) were determined using various analytical techniques. The concentrations of heavy metals were analyzed using a Microwave Plasma Atomic Emission Spectrometer (MP-AES), and the measured concentrations were used to evaluate the pollution load index (PLI). The findings of the study revealed that mining activities had a significant impact on the physicochemical characteristics of the soils, with lower pH, CEC, and SOM values in particular in active and abandoned mining sites. The physico-chemical characteristics of soil vary seasonally, with higher values typically reported during the rainy season, except for pH. The concentrations of arsenic, cadmium, lead, and zinc in the soils of the Riruwai mining area exceeded the threshold value recommended by WHO/FAO (2001) in all the sampling locations and seasons, with the exception of the control sites. The PLI values indicated that the soils in active and abandoned mining sites are strongly polluted by heavy metals, while farmland soils are moderately polluted and control site soils are unpolluted. The soils in the study area are significantly contaminated by heavy metals, particularly in active and abandoned mining sites, and the contamination has spread to farmland, suggesting a significant need for proper containment of heavy metal pollution levels in the area, particularly arsenic, cadmium, lead, and zinc.

Water Quality Index and Heavy Metal Pollution Index of Groundwater Quality: A case Study in Visakhapatnam District, AP.

The main objective of the present study was to assess the groundwater quality of selected Mandals in Visakhapatnam district Andhra Pradesh. Fifty samples were collected from hand pumps of various Mandals. Water Quality Index (WQI) and Heavy Metal Pollution Index (HPI) along with Metal Quality Index (MQI) were determined. Physicochemical parameters such as pH, Electrical Conductivity (EC), Total Hardness (TH) and Total Dissolved Solids (TDS) were measured by various standard techniques. Calcium (Ca+2), Magnesium (Mg+2), Chloride (Cl-), Nitrate (NO3 -) and Sulfate (SO4 -2) were analyzed by 930 Compact Ion Chromatograph Flex. Heavy metals such as Lead (Pb), Zinc (Zn), Chromium (Cr), Aluminum (Al), Copper (Cu), Nickel (Ni), Manganese (Mn) and Cadmium (Cd) were analyzed by using 4200 Microwave Plasma – Atomic Emission Spectrometer (MP-AES). Iron (Fe) was analyzed by Cary 60 UV-Visible Spectrophotometric method. The correlation coefficient (R2) of the heavy metals lies between 0.99 to 0.98. The compliance of BIS 10500:2012 for the heavy metal concentration in drinking water was verified. From the current study, it was found that EC, TDS, TH and heavy metals such as Aluminum (Al) and Lead (Pb) exceeded the allowed limits as per BIS 10500:2012 revision. The highest values of HPI and WQI from the fifty groundwater samples are 407.97 and 189.79. The highest value of MQI is 3.36 respectively. An attempt has also been made to draw spatial distribution maps for heavy metals having higher concentrations in the study area.

Impact of Overlithiation and Al doping on the battery performance of Li-rich layered oxide materials

Lithium rich layered oxides (LRLOs) are one of the best alternatives for the next generation positive electrodes materials for Li-ion batteries. However, LRLOs suffer a remarkable voltage decay upon cycling that prevents stable and prolonged electrochemical performances and contains large quantities of cobalt in the transition metal blend. Here, we demonstrate the performance in batteries of a series of innovative materials with general formula Li1.2+xMn0.54Ni0.13Co0.13-x-yAlyO2 (where 0.03≤x ≤ 0.08 and 0.03≤y ≤ 0.05) capable to supply large reversible specific capacities (around 200 mAh g−1), stable cycling performance with reduced voltage decay. This communication sheds light on the interplay between structural and electronic disorder induced by Al/Li co-doping in LRLO and the corresponding functional properties in batteries. The impact of substitution of cobalt by Li and Al co-doping on the structural and morphological properties has been examined by Synchrotron X-ray diffraction (XRD), microwave plasma atomic emission spectrometer (MP-AES) and scanning electron microscopy (SEM). Furthermore, to better understand the structure-function interplay of these over-lithiated materials, ex situ analyses are here reported coupling Synchrotron X-Ray diffraction and Raman Spectroscopy. Based on the obtained results, we proved that coupling the over-lithiation with the aluminum doping, is an effective strategy to reduce the cobalt content into the LRLOs structure maintaining high electrochemical performance. Beside the values of specific capacities obtained in lithium cells, these materials exhibit excellent capacity retention and voltage retention, in particular for the material with the smallest content of cobalt, i.e. Li1.28Mn0.54Ni0.13Co0.02Al0.03O2. Furthermore, thanks to the ex-situ analysis of the latter, we explained the structural evolution of the sample upon cycling that showed the formation of a secondary trigonal phase and the occurrence of limited local distortions of layered structure.

INVESTIGATION OF THE SOLID MINERAL DEPOSITS IN KANO STATE'S SCHIST BELT USING GEOCHEMICAL ANALYSIS

This paper uses geochemical analysis to investigate solid mineral deposits in Kano state's schist belt. A number of geophysical studies have recently focused on the area, with one of them estimating the causative body parameters through modeling of ground magnetic data collected in the study area; a follow-up study like this is thus required. Using an Agilent Microwave Plasma-Atomic Emission Spectrometer (MP-AES), eight rock samples from the study area were prepared for geochemical analysis. The study area was discovered to be rich in iron, chromium, aluminum, silicon, calcium, potassium, zinc, and manganese, with mean values of 157.10, 6.35, 274.71, 324.76, 27.83, 239.79, 25.49, and 160.20 ppm, respectively. Muscovite, Fuchsite, Biotite, Chlorite, and Quartz are schist minerals rich in these elements. Gold and silver were also discovered, although in small quantities, with mean values of 0.15 and 0.03 ppm, respectively. It is recommended that government and other stakeholders in the solid mineral industry should explore the study area in order to exploit these resources. It is also recommended that a radiometric study be conducted in the area to determine the presence of thorium and uranium, as well as the area's safety from radioactive hazards due to the high amount of potassium recorded.

Green synthesis of Co-doped ZnO via the accumulation of cobalt ion onto Eichhornia crassipes plant tissue and the photocatalytic degradation efficiency under visible light

Nowadays, water pollution is a major concern to the globe. For this reason, various research works has been done to access pure water thereby minimizing the effect of pollutants. In this work, the cobalt doped ZnO (Co-doped ZnO) via the accumulation of cobalt ion onto Eichhornia crassipes plant tissue for different days and combined with zinc precursor was synthesized. The resulting catalyst powder samples were characterized by Fourier transform infrared (FTIR) spectroscopy, X-ray diffraction (XRD), X-Ray photoelectron spectroscopy (XPS), field emission scanning electron microscopy (FE-SEM), and Ultraviolet–vis (UV–vis) spectroscopy, and microwave plasma atomic emission spectrometer (MP-AES). The catalysts were also tested for the photocatalytic degradation of methylene blue (MB) in the presence of H2O2 under visible light irradiation. The best catalytic activity was gained by the 8th-days accumulation of cobalt ion onto the Eichhornia crassipes plant tissue and 99.6% of the dye was degraded within 45 min. However, 69.6, 65.7, 73.6, and 94.8% of MB dye was degraded by 1, 2, 4, and 6 days accumulations. Hence, removal of toxic heavy metal by using Eichhornia crassipes plant and recycling in the wastewater treatment gain is highly appreciated. Moreover, the Co-doped ZnO photocatalysts could enhance the photocatalytic activities due to suppressing of the electron and hole recombination and the porosity of the catalysts resulted from the Eichhornia crassipes plant after calcination.

Health risk assessment of heavy metals in irrigated fruits and vegetables cultivated in selected farms around Kaduna metropolis, Nigeria

ABSTRACT This study assessed heavy metals levels in water, soil, fruits (banana, pawpaw) and vegetables (cucumber, cabbage and garden egg) from Bashama, Danmani and Danbushiya farms within Kaduna metropolis, Nigeria. A total of 63 samples (water (9), soil (9), fruits and vegetables (45)) were randomly collected, processed and analyzed for heavy metals using a microwave plasma atomic emission spectrometer. The heavy metal concentration in soil was found to be highest for Fe (57.30–63.51) mg/kg and the least was observed for Cu (0.45–1.45) mg/kg. High levels of Pb (0.02–0.03) mg/l, Cd (0.07–0.1) mg/l and Fe (3.23–3.42) mg/l were determined in the irrigation water exceeding the World Health Organization (WHO) standard. Some of the heavy metals (Fe, Zn and Cu) found in the various fruits and vegetables were essentials metals. Toxic metals like Pb and Cd were also present with concentrations above the World Health Organization permissible limit of 0.2 and 0.1, respectively. In the fruits and vegetables examined, the average mean concentration of metals showed significant variations with Fe having highest concentration of (7.82 mg/kg) in most of the samples from the farms. Health risk assessment of heavy metals from the fruit and vegetable samples indicated that all metals are within hazard quotient limit of less than 1 except for Cd, while for the hazard index, all the metals surpass limit of 1 which showed that the samples are likely to be of health concern. For permissible maximum tolerable daily intake in the metals studied, Cd has the highest concentration. The activities around these farms play a significant role in elevating the concentration of Cd and Pb in the fruits and vegetables a little above the WHO set standard of 0.3 mg/kg and 0.2 mg/kg, respectively. Measures to reduce the concentration of heavy metals in fruits and vegetables should be carried out in further works to avoid their health risk in human.

Lithium in drinking water, altitude, and suicide rates in rural areas of Argentinean Andes

The Lithium Triangle in the Andean plateau involves high altitude (>3,000 m asl) hydrological systems having high lithium graded waters. This research was carried-out in rural areas of north westernmost Argentinean Andes and was aimed: 1) to determine concentrations of lithium in drinking waters; 2) to calculate suicide mortality rates based on available official data (2003–2013); 3) to analyze bivariate differences between lithium concentrations in drinking water, mean rates of suicide mortality, altitude of sampling sites, and water sources; 4) to analyze bivariate correlations between lithium concentrations in drinking water, mean rates of suicide mortality, and altitude; 5) to test predictive models for mean rates of suicide mortality, when considering the predictors lithium concentrations in drinking water, altitude, and water sources. Lithium determinations in drinking waters were performed by Microwave Plasma-Atomic Emission Spectrometer. Nonparametric tests were applied to analyze differences and correlations. Generalized linear models (GLM) were used to fitting models for mean rates of suicide. Drinking waters contained up to 2.98 mg L−1 of lithium. Mean rates of suicide mortality (per 100,000 inhabitants) were high, ranging from 19.12 (± 19.83) to 30.22 (± 16.70). Lithium but not altitude was positively correlated with suicide mortality when analyzing bivariate correlations (Li: rho = 0.76, p-value < 0.001). However, when GLM were calculated, a significant interaction effect was found between lithium and altitude (p-value < 0.001). This interaction effect would act in some way restraining the suicide mortality rates.