Atomic Absorption Spectrometer Research Articles

Characterization of Metakaolin from Wassa Kaolin and Its Potential as Adsorbent for the Regeneration of Used Engine Lubrication Oil

Metakaolin is an anhydrous clayey material obtained by the calcination of kaolin. This material has been utilized as a valuable substitute or additive for concrete/cement mixtures and many other applications. The current study is on the production and characterization of metakaolin together with its adsorbent properties for the purification and regeneration of spent lubrication oil. Metakaolin was produced from the calcination of kaolin from Wassa in the Western region of Ghana. The metakaolin was characterized by using X-ray fluorescence (XRF), X-ray diffractometry (XRD), scanning electron microscopy (SEM) coupled with energy dispersive X-ray (EDX), and Fourier transform infra-red (FT-IR). The metakaolin was then used as an adsorbent in the regeneration of the engine lubrication oil, mimicking the acid-clay percolation process. The test results show that the efficiency of metakaolin in removing heavy metals from the used oil using an atomic absorption spectrometer (AAS) was 13.25% for Fe, 25.37% for Cr, 94.36% for Zn, and 33.33% for Cu. The viscosity index of the regenerated oil was 118 compared to that of the virgin oil, which was 115. The regenerated oil had 79% saturates, 6% carbon residues, and 18% aromatics compared to the commercial virgin oil, which contained 84% saturates, 5% carbon residue, and 11% aromatics. This indicated that metakaolin is a better adsorbent for regenerating the used lubrication oil.

Local fruit peel biosorbents for lead(II) and cadmium(II) ion removal from waste aqueous solution: A kinetic and equilibrium study

Heavy metals are serious causes of water pollution affecting both living organisms and human life. This research focuses on the removal of Pb(II) and Cd(II) ions from waste aqueous solution through adsorption process using natural biosorbents chemically modified from three local fruit peels comprising dragon fruit peel (DFP), rambutan peel (RP), and passion fruit peel (PFP). Their surface morphologies and functional groups were consecutively determined using scanning electron microscope and Fourier transform infrared spectrometer. Concentrations of the adsorbed metal ions were quantified using atomic absorption spectrometer. Adsorption experiments were carried out with varying adsorbent dosages, pH values, contact time, and initial lead(II) and cadmium(II) concentrations. An adsorbent dosage of 0.25 g, a pH of 4, a contact time of 180 min, and an initial concentration of 100 mg/L were found to be the optimal set of conditions for biosorption of Pb(II) and Cd(II) ions. The chemically modified groups showed the highest percentages of Pb(II) and Cd(II) removal at 97.867% and 97.100% for RP, respectively. The adsorption proceeded according to the pseudo-second-order kinetic model. The adsorption data were consistent with the Langmuir and Freundlich isotherm models, but the Langmuir model provided the best fit. The Langmuir monolayer adsorption capacity values of biosorbents were determined to be 97.087 mg(Pb2+)/g, 114.943 mg(Pb2+)/g, 103.093 mg(Pb2+)/g, and 86.207 mg(Cd2+)/g, 102.041 mg(Cd2+)/g, 89.286 mg(Cd2+)/g for DFP, RP, and PFP, respectively. The results indicate that these biosorbents could be able to efficiently remove Pb(II) and Cd(II) and serve as economic and promising adsorbents for heavy metal removal from contaminated wastewater.

Molecular simulation and experimental investigation on enhancement of microbe cement in municipal solid waste incineration fly ash

The enhancing effects of microbe cement on municipal solid waste incineration (MSWI) fly ash have been modeled by molecular dynamics and investigated experimentally. Molecular dynamics is utilized to explore the adsorption mechanism of heavy metal (Pb ions) in cementitious materials in four aspects: intensity distribution, mean square displacement (MSD), radial distribution function (RDF) and time correlation functions (TCF), revealing that the stable formation of chemical adsorption with C-S-H is the main reason. So the leaching of heavy metals can be reduced with cement hydration such as microbe cement with MSWI fly ash. Furthermore, the strengthening effects of microbe cement are inspected experimentally with a compression test, X-ray diffraction, scanning electron microscopy and atomic absorption spectrometer with a content range from 0 to 60%. The results of compressive strength, microstructure inspection and heavy metals’ leaching concentration show that the optimum content of microbe cement for solidifying and enhancing MSWI fly ash is 30% above range.

Cloud point extraction and Flame Atomic Absorption Spectrometry in the determination of Cu (II), Cr (III), Cd(II), Fe(III) and Mn(II) using Glycerin and PO/EO-block polymer as a surfactant

A simple cloud point extraction (CPE) method has been proposed for the separation & preconcentration for determination of Cr3+, Cu2+, Cd2+, Fe3+ and Mn2+ ions by complexation with ammonium pyrrollidine dithiocarbamate (APDC) in the presence of Glycerin and PO/EO-block polymer. The phase separation occurred when micellar solution was heated at 60◦C. A complete separation of the metal ions with and without addition of chelating agent could be achieved at PH= 3-10 the efficiency of separation is 85-100%. Glycerin showed 75-100% separation for Cr3+, Cu2 and Mn2+ while PO/EO-block polymer showed 60-99% for Cd2+and Fe3+. Other factors also tested include surfactant and metal ions concentration, temperature, time and foreign ions. One gram of surfactant is an enough amount for separation of 20 ppm of each metal ion solution. The analysis of metal ions were carried out using flame atomic absorption spectrometer with deuterium lamp background correction and calibration curve method.

Plant biomass as potential economic commodities for agricultural purposes.

The world’s population is growing continually and is projected to reach nine billion by the year 2050. This growth rate requires increased and economically viable food production and an adequate supply of quality water to sustain life. Increased food production and supply of water require adding fertilizers and possible recycling of wastewater, to address the improvement of soils’ nutritional status and potable water shortages, respectively. The objectives of this work were to determine the nutrients in sewage-impacted wastewater, borehole water, agricultural waste, and commercial fertilizer (control) materials, and their heavy metal content was also carried out to determine their suitability for use. In addition, Moringa seed pods and Morula nutshells were investigated as a bioremedial approach for the removal of toxic metals from aqueous samples. An attempt to regenerate sorbent was made since the saturated sorbents that contain the metal ions are not safe for disposal as they can pollute the environment. Nutrients were analyzed by HPLC, while metals were analyzed using a Varian 220FS Atomic Absorption Spectrometer operated with air/acetylene. Nonedible agricultural materials were found to contain appreciable amounts of plant nutrients such as nitrates (NO3 -), nitrites (NO2 -), and phosphates (PO4 3-) as well as metal ions such as magnesium, copper, and zinc, which are beneficial for plant growth. Results obtained from analysis of sewage water effluent showed that heavy metal and nutrient concentrations decreased in the treatment stage. The utilization of Moringa oleifera seed pods for metal removal from wastewater is viable and would reduce costs for waste disposal and can offer alternatives to conventional methods for the removal of unwanted or toxic species from the environment. It showed potential for removing selected metal ions such as Pb, Cd, Cu, Fe, and Zn from polluted water. This organically treated wastewater is environmentally friendly and may be used for applications which do not require potable water, such as irrigating golf courses, lawns, and crops, or for industrial purposes, if proper measures are taken to ensure its quality.

Effects of lead exposure on biomarkers of thyroid and renal function tests among panel beaters in Enugu Metropolis, Nigeria.

Occupational lead (Pb) exposure causes multisystem effects at high and sustained low doses. However, there are inconsistencies in the dose-response effects on the thyroid and kidneys. This study aimed to assess the effects of Pb exposure on the biomarkers of thyroid and renal functions among panel beaters in Enugu Metropolis, Nigeria. This was a cross-sectional analytical study of 428-panel beaters selected using a multistage sampling technique. Blood lead (BPb), thyroid, and kidney biomarkers were analyzed using atomic absorption spectrometer at 238.3 nm wavelength, enzyme-linked immunosorbent assay, and automated chemistry analyzer, respectively. Analyses were performed using median, mean, Chi-square, correlation, and statistical significance. The median BPb levels were 10.0 μg/dl among participants with about half, 211 (49.3%) having BPb within reference levels. Though the mean values of thyroid stimulating hormone (TSH), free thyroxine (FT4), free triiodothyronine (FT3), and creatinine (Cr) were within the reference values, the majority of 275 (64.25%) of the participants had non-euthyroid statuses. Significant differences were found in TSH (P = 0.001), thyroid status (P = 0.0129), and estimated glomerular filtration rate (P = 0.00384) between those with BPb within reference level and those with elevated levels. Though the mean levels of thyroid hormones and Cr were within their respective reference intervals, there was a preponderance of non-euthyroid status among participants in the present study with the majority of the participants falling within CKD grades 2 and 3.

Comprehensive study of heavy metal pollution in surface water of Guntur region of Andra Pradesh

The Water pollution is known of as the apperence of undesirable elements that are introduced into a natural water supply by human activity, changing its physical, chemical, or biological properties. The present study was conducted in the Guntur region of Andra Pradesh. The surface water samples were assembled from ten sample stations and analyzed for their heavy metal content by atomic absorption spectrometer (AAS). The acquired values were also compared to permissible limits. Magnesium and lead were detected in the surface water collected from all 10 sample stations. However, June 2019 surface water collection showed significantly (p<0.001) amount of magnesium as compared to other seasons collections. Sample stations 2, 6, 7 and 8 showed maximum concentration (>0.2ppm) of lead during December 17, June 18, June 19 and June 18, respectively. Selenium was detected in the surface water collected during four intervals from all sample stations except sample station 7. Arsenic was detected in the surface water collected from sample stations 1, 2, 3, 5, 6, 8 and 9. However, maximum concentration of both the elements was detected in the surface water collected from sample station 3 as compared to remaining sample stations. The Bandarupalle sample station showed presence of copper, nickel, chromium, iron, manganese, cadmium, mercury and molybdenum. The Tadikonda sample station showed copper, nickel, chromium, zinc, iron, and mercury. Mangalagiri and Mutluru sample station showed copper, cobalt, nickel, chromium, zinc, iron, manganese, cadmium, mercury and molybdenum in surface water which were found to be maximum polluted stations. The Chebrolu showed presence of all above elements except manganese. The Rompicherla and Guntur sample station surface water showed presence of all the above mentioned elements except copper and cadmium. Pedda Vadlapudi surface water detected nickel, chromium, zinc, iron, manganese, cadmium, and mercury. The Macherla showed presence of nickel, chromium, iron, cadmium, mercury and molybdenum. Acharya Nagarjuna University showed cobalt, nickel, chromium, iron, manganese, cadmium, and molybdenum in the surface water. Lead, arsenic, selenium, chromium and mercury were found to be above permissible limits in the surface water.

Development of a miniaturized hydride generation-dielectric barrier discharge atomic absorption spectrometer

A miniaturized atomic absorption spectrometer (AAS) was proposed with a planar dielectric barrier discharge (DBD) microplasma as an atomizer, a charge coupled device (CCD) spectrometer as a spectral detector, and a hydride generation (HG) unit as a sampler, and the potential analytical capability was evaluated through the determination of cadmium. Auxiliary hydrogen was added to enhance the atomic absorption signals and the potential mechanism of enhancement effect was studied by use of various techniques. The HG-DBD-AAS was further applied to the determination of Cd, yielding a 1.7-fold enhancement in AAS response with added hydrogen and a limit of detection (LOD) of 0.3 μg L−1 under optimized conditions. Good agreement with the certified values, and desirable spike recoveries ranging between 98% and 108%, were obtained for two certified reference materials and several real water samples, respectively. It can be useful in field analysis of many trace elements with high detectability.

Assessment of Heavy Metal Concentration in Soil and Plant and Evaluation of Bioconcentration Factor at Loumbila Market Gardening Perimeters, Burkina Faso

Agricultural soil quality deterioration resulting from an increase in the level of heavy metals is becoming more and more pronounced, thus raising the question on the safety status of human health and the environment. Determination of heavy metal concentration in soils and plants from Loumbila market gardening (Burkina Faso), and calculation of bioconcentration factor were undertaken. The heavy metals such as copper (Cu), nickel (Ni), lead (Pb), chromium (Cr), cadmium (Cd) and zinc (Zn) were measured using an atomic absorption spectrometer, model PERKIN ELMER AANALYST 200.&#x0D; In the soil where the pepper was grown, the concentration of chromium was 175 mg/kg, which is higher than the concentration limit which is 150 mg/kg. Also the concentrations of lead in the soils of onion (118 mg/kg), green bean (118 mg/kg), carrot (178 mg/kg) and pepper (135 mg/kg) were above the limit which is 100 mg/kg. The concentrations of chromium in Onion leaves (3.72 mg/kg), onions (4.65 mg/kg), lettuce (4.89 mg/kg), green beans (5.89 mg/kg) and bell peppers (3.56 mg/kg) were concentrations above the limit established by the FAO/WHO, which is 2.3 mg/Kg. The concentrations of lead in carrot, onion leaf, onion, lettuce, green bean and bell pepper were above the limit proposed by FAO/WHO.&#x0D; The bioconcentration factors show that the onion leaf (0.731), onion (0.929), lettuce (0.876), green bean (0.987) and bell pepper (0.858) are the plants that accumulate zinc and the carrot (0.524) accumulates nickel. The bioaccumulation of the metals in the vegetable from Loumbila market gardening decreased in the order of onion &gt; lettuce &gt; green bean &gt; bell pepper &gt; onion leaves &gt; carrot.

The role of thiosulfate and sulfite in gold thiosulfate electrowinning process: An electrochemical view

In this study, electrochemical and analytical techniques are employed to explore the effect of thiosulfate, sulfite, and a mixture of thiosulfate-sulfite in the electrolyte on the gold electrowinning process. The open circuit potential (OCP) analysis showed negative potential shifts from − 0.02 V (in the electrolyte containing Au-TS (E1)) to − 0.21 V, − 0.33 V, and − 0.42 V in the presence of thiosulfate oversupply (electrolyte E2), sulfite (electrolyte E3), and thiosulfate-sulfite mixture (electrolyte E4). The linear sweep voltammetry (LSV) results exhibited − 0.4 V potential shift by the addition of sulfite to the gold-thiosulfate electrolyte, attributing to the formation of Au(S2O3)(SO3)25- as the most stable gold complex. Based on chronoamperometry (CA) and atomic absorption spectrometer (AAS) results, sulfite could control the kinetics and thermodynamics of gold reduction reactions by minimizing undesired cathodic side reactions such as thiosulfate decomposition or water reduction, resulting in purer gold deposition, elimination of colloidal sulfur, and a more efficient EW process. The presence of thiosulfate accelerated the kinetics of the gold reduction reaction. However, adding sulfite to the electrolyte stabilized the kinetic about 10 times faster. SEM and EDS analysis depicted the morphological changes in the deposited gold layer from different electrolytes during CA, showing that thiosulfate oversupply results in the formation of a greater number of smaller grains by accelerating the nucleation process, while sulfite addition led to the formation of a smoother and more uniform gold layer on the cathode surface.

Variability of Heavy Metal Content of Phytomedicine from Foreign and Local Source Sold in Nigeria.

The popularity of herbal products has been on increase throughout the world; but one major challenge facing it is lack of guaranteed safety with respect to heavy metals contamination. In this study, Chinese, Indian and Nigerian phytomedicine were evaluated for Copper (Cu), Cadmium (Cd), Lead (Pb) and Zinc (Zn) in order to ascertain and compare their safety or level of contamination. The samples were purchased, processed and analyzed using Flame Atomic Absorption Spectrometer (FAAS). The results obtained were presented as mean concentrations of Cu, Cd, Pb and Zn in the Nigerian, Chinese and Indian phytomedicine as 1.23±0.03μg/g, 5.46±0.04μg/g, 5.16±0.01μg/g (Cu), 2.07±0.04μg/g, 9±0.06μg/g, 6.28±0.03μg/g (Cd), 4.42±0.18μg/g, 7.74±0.07μg/g, 5.05±0.06μg/g (Pb) and 2.90±0.04μg/g, 6.40±0.04μg/g, 2.53±0.04μg/g (Zn) respectively. The results indicated all the Nigerian herbal remedies analyzed and 33.33% of the Chinese and Indian herbal remedies contained cadmium above WHO permissible limit (0.3 μg/g) for herbals. The analysis of variance (ANOVA) results obtained at p-value 95% (p ˂ 0.050) ranges from significant to non-significant difference of means among the three countries. The correlation coefficient (r) also ranges from negative to strong degree of association. The variability of the heavy metals content could be associated to geographical, environmental, anthropogenic factors and heavy metals absorption potentials of the medicinal plants used. Environmental monitoring of herbal materials is required in order to ensure their safety from chemical pollutants that could lead to bio-accumulation of heavy metals in herbal materials.

Heavy Metal Contamination of Pleurotus Tuberregium Sclerotia (Osu) Consumed in Enugu, South East Nigeria

Heavy metal contamination of food is a global public health problem especially in developing countries. The WHO 2015 report on global burden of food contamination stated that an estimated 600 million people are affected resulting in 420,000 deaths annually with children under 5 years of age constituting 40% of burden and 125,000 deaths annually. The present study was aimed at determining the concentrations of Nickel (Ni), Cadmium (Cd), Lead (Pb) and Chromium (Cr) in some samples of wild type pleurotus tuberregium sclerotia consumed in Enugu, Southeast Nigeria. Heavy metal concentrations were determined using Atomic Absorption Spectrometer (AAS 240FS) Varian, Varian Inc, Japan. The range for concentration of Nickel was (3.29+0.63-3.67+0.00), Cd (0.002+0.01-0.005+0.0), Pb(0.04+0.03)-0.07+0.02) and Cr(0.46+0.26-1.0+0.62),ppm respectively. These are within the WHO tolerable concentrations of Ni, Cd, Pb and Cr in food. These findings shows that pleurotus tuberregium sclerotia consumed in Enugu has lower concentrations of heavy metals compared to the WHO recommended values.

Heavy Metal Bioaccumulation and Histopathological Studies of Fish Tissues from Ose River, Ondo State, Nigeria

The exposure of the aquatic ecosystem to heavy metal from both natural and anthropogenic activities are on the rise and have harmful health effects on all aquatic organisms and human. This study assessed the concentrations of heavy metals (Fe, Pb, Cd, Cr, As and Zn) in surface water, sediments and fish tissues of Ose River and examined the histopathological changes of the tissues of two fish species (Mormyrus rume and Clarias garienpinus). Surface water, sediments and fish samples were collected and procured from Ose River in Ondo State, Nigeria from February to April 2021. Heavy metal digestions were done in the laboratory using HNO3/HCl while the concentrations were determined using Atomic Absorption Spectrometer. Histopathological alterations in the fish tissues were also assessed. Bioaccumulation factor (BAF), ecological risk index and potential ecological risk level were used to assess the investigated metal concentrations. In the surface water, the concentration of Cd (0.010–0.030 mg/l) and As (0.010–0.05 mg/l) exceeded the WHO limits of 0.01mg/l respectively while Fe, Pb, Cr and Zn were within the limits. In the sediments, all metals exceeded the limits except Pb and As. The concentrations of Pb (0.30±0.000–4.12±0.030 mg/l), Zn (9.970±0.010–30.77±0.023 mg/l), Cd (0.026±0.002–0.331±0.004 mg/l) and Cr (ND-0.331±0.004 mg/l) in the fish tissues were seen to be higher than the permissible limits of 0.5 mg/l, 5 mg/l, 0.005 mgl and 0.05-0.15 mg/l respectively. The BAF showed no probability. The alterations observed in the kidneys of the fish were cholestasis, necrosis, loss of glomeruli structure and tubular necrosis. While the gills showed congestion of the central veins and interlamellae hyperplasia caused by the presence of a monogenean parasite. The livers however revealed loss of hepatocytes nuclei, necrosis in hepatocytes and lymphocytic infiltrate. The study showed that the study site was polluted with heavy metals and may pose serious health issues to fishers, those using the water and people feeding on fish from the river. This study therefore suggests good indicators for bio-monitoring of heavy metals in Ose River. Seeing that the site was polluted with heavy metals hence, a more comprehensive assessment of the river is recommended.

Detection of heavy metals in children playing products and its associated health risk assessment in Lahore, Pakistan

ABSTRACT Children have higher threats due to their exposure and higher susceptibility to the environmental pollutants. The current study put an effort on detecting different heavy metals in children play products and its related effects on children’s health. Heavy metals were detected in the selected samples from the local markets of city Lahore by using flame atomic absorption spectrometer (iCE 3000 series). Results showed that the concentrations of heavy metals (Cr, Ni and Zn) except Pb and Cd are below the EU migration limits. The concentration of Pb in all samples and the concentration of Cd in nineteen samples exceeds from the limits. Highest values of Pb and Cd detected in poster paints were (8.33 ± 1 mg/kg) and (0.94 ± 0.1 mg/kg), respectively. In crayons and playing dough highest values of Pb and Cd detected were (10.94 ± 1 mg/kg), (2.75 ± 0.1 mg/kg) and (9.313 ± 01 mg/kg), (1.9 ± 0.1 mg/kg), respectively. Obtained results are further used to calculate both the oral and dermal health risks of these playing products. The value of the total health risk assessment was less than 1 in all the selected playing products. The maximum value of the total health risk assessment is detected in crayon (3.97E-02), which can cause serious health problems. Therefore, it is needed to make laws which limit the use of heavy metals in these playing products in Pakistan.

Effects of Refining and Petrochemical Effluents on Water Quality and Zooplankton Community in River Rido Kaduna, Nigeria

Kaduna Refining and Petrochemical Corporations (KRPC) discharges were studied for a year along the river Rido to determine their impact on water quality and the distribution and abundance of Zooplankton. Physical and chemical parameters were measured following American Public Health Association (APHA) standards for evaluating wastewater. An atomic absorption spectrometer (AAS) was utilized for heavy metal analysis. For this experiment, we used a Plankton net with a 25 m mesh size and a specimen bottle with a 10 cm diameter ring opening to collect zooplankton. Zooplanktons were identified using a standard key and a monograph. Water quality parameters fluctuated, but all were within acceptable ranges except for temperature, conductivity, Total Dissolved Solid, and lead. Zooplanktons were represented in order of abundance by 8 species of protozoa constituting 72.44%, followed by 12 species of Rotifera (10.58%), followed by 13 species of Cladocera 9.55% and then 6 species of Copepoda (7.44%). The planktons showed seasonal variation with high density recorded during the wet season in all the stations. There was a low density of zooplankton in station B, while high density was observed in stations A and D. Also, the low transparency and dissolved oxygen (DO) as well as high mean values of temperature (30.88 oC), chloride (31.88 mg/L), lead (0.099 mg/L), TDS (224.17 mg/L) and conductivity (334.28 µS/cm) observed were above FEPA limits at station B were an indication of pollution and deterioration of water quality. This research revealed that the effluent discharge from KRPC has adverse effects on the zooplankton community and the water quality of river Rido.

Tin Concentrations and Human Health Risk Assessment for Children and Adults in Seafood and Canned Fish commonly consumed in Bayelsa State, Nigeria

Tin is a naturally occurring element in the environment, and the most important dietary intake is from tin-plates steel cans used for food packaging. The objective of this paper is to evaluate the tin concentrations and human health risk assessment of children and adults in seafood and canned fish (Sardine and Mackerel) obtained from Bayelsa State, Nigeria using the Thermo-Elemental Atomic Absorption Spectrometer (S4-71096 model) after mixed-acid digestion. Data obtained reveal tin concentrations (mean ± SD, mg/kg) in seafood in the order of fresh water fish (0.99 ± 0.07) salt water fish (0.98 ± 0.16) salt water–Blood Clam (0.75 0.022) fresh water- Clam (0.17 ± 0.12) fresh water-Prawn (0.06 ± 0.01) salt water shrimp (0.02 ± 0.01) respectively, tin concentrations in the brands of canned fish were significantly higher than the concentration in seafood (p &lt; 0.05). However, the mean concentrations of tin in the seafood and brands of canned fish were lower than the standard guideline limits set by regulatory bodies (200 mg/kg - 250 mg/kg). The health risk exposure assessment revealed that the values of all the samples were lower than the provisional maximum tolerable daily intake (PMTDI) of tin. The target hazard quotient (THQ) values of tin for both children and adults in all the samples were also lower than the reference dose (RfD). The health risk index (HRI) values of the seafood and the brands of canned fish for both children and adults were less than 1.0, which indicates that there are no adverse effects at the moment. However, the HRI values of the brands of canned fish were higher than the seafood for children and adults. Hence, assessment of tin in seafood and canned food could be periodically assessed by Nigerian food and drug regulatory organizations for efficient policy regulations.

ST2 and the alteration of cobalt, sodium, potassium and calcium concentration in acute inflammation

IntroductionST2 is the receptor for interleukin (IL)-33, the last discovered member of the IL-1 cytokine family. Acute inflammation is an early response of vascularized tissue to injury, in which alteration of micro- and macro-elements occurs. This study aimed to examine the alteration of cobalt, sodium, potassium, and calcium concentration at the site of acute inflammation and the role of ST2 in these alterations. Material and methodsWild-type (WT) and ST2 knockout (ST2−/−) mice were divided into groups: WT control group (WT-C), ST2 knockout control group (KO-C), WT inflammatory group (WT-I), and ST2 knockout inflammatory group (KO-I). We induced acute inflammation by intramuscular injection of turpentine oil or saline in the case of the control group. After 12 h, we anesthetized mice and collected treated tissues for histopathological analysis and determination of cobalt, sodium, potassium, and calcium concentration by atomic absorption spectrometer. ResultsHistopathological analysis showed the inflammatory infiltrate and cell necrosis in the treated tissue in WT-I and KO-I. The concentration of sodium was significantly lower in WT-I than in WT-C. The concentration of potassium and cobalt was significantly lower in WT-I and KO-I when compared to WT-C and KO-C, respectively. However, the concentration of potassium and cobalt in the tissue was significantly lower in WT-I than in KO-I. The concentration of calcium in the tissue did not significantly differ between groups. ConclusionWe reported, to our knowledge for the first time, that ST2 is involved in decreasing sodium, potassium, and cobalt concentration at the site of acute inflammation.

Analysis of toxicological safety of feed by atomic absorption spectroscopy

Currently, one of the main indicators characterizing the safety of feed for productive animals is the content of toxic elements in them. According to the requirements of MDU No. 123-4 / 281-8-87 "Temporary maximum allowable level (MRL) of the content of certain chemical elements and gossypol in feed for farm animals and feed additives", mercury, cadmium, lead are of the highest veterinary, sanitary and toxicological significance, arsenic, selenium. The danger of these substances lies in the ability to accumulate in the body of an animal and cause various pathologies, affecting the urinary, hematopoietic, digestive and nervous systems, generally retard the growth and development of farm animals, reduce resistance, productivity and increase the risk of detecting toxicants in agricultural products of animal origin.The purpose of the study was to assess the safety of plant foods for the content of mercury, arsenic, selenium, lead and cadmium using atomic absorption spectroscopy. The study materials were 76 samples of various plant foods for productive animals: grass meal, linseed cake, oats, vegetable feed. The amount of toxic elements was determined according to GOST R 55447-2013 and GOST 31651-2012 using an MGA-1000 atomic absorption spectrometer with Zeeman correction of non-selective absorption (LUMEX Group of Companies).As a result of the studies, it was found that in all samples of plant-derived feed for productive animals, the amount of toxic elements did not exceed the maximum allowable level. Thus, the amount of mercury in the studied samples averaged 0.55±0.04 mg/kg, cadmium - 0.86±0.04 mg/kg, lead -0.29±0.01 mg/kg, arsenic - 0 .24±0.01 mg/kg, selenium – 0.44±0.02 mg/kg. The established concentrations of toxic elements did not exceed 1.0 mg/kg and were less than 1.5% of the maximum allowable level, which meets the requirements for the toxicological safety of feed for productive animals.

Heavy metal concentrations in Caspian pond turtle (Mauremys caspica) in Zarivar International Wetland, Kurdistan Province of Iran.

In the present study, the cadmium, lead, and zinc levels in the blood and shell of Caspian pond turtles (Mauremys caspica) were investigated at five stations in Zarivar International Wetland in Kurdistan Province. All specimens were released at their capture locations within 2h of capture. Water samples were collected at each station. Heavy metal concentrations were determined using an atomic absorption spectrometer. The mean cadmium, lead, and zinc concentrations were 0.04, 32.10, and 11.45mg/l in blood samples; 1.82, 16.91, and 89.22mg/l in shell samples; 0.005, 1.30, and 0.07mg/l in water samples, respectively. In this study, the highest metal adsorption was zinc and was observed in shell. According to the results of this study, the shell of the Caspian Pond Turtle can be used to estimate the concentration of heavy metals. Our results suggest that Caspian pond turtle can be used as a biological indicator to estimate heavy metals.

A new magnetic metal–organic framework composite synthesized via a post-synthetic functionalization approach for ultra-trace extraction/determination of mercury in real matrixes

Herein, a novel magnetic metal–organic framework (MMOF) composite was prepared via a post-synthetic modification method was employed to the ultra-trace determination of mercury in food samples. At first, magnetite nanoparticles were fabricated and afterward functionalized with a SiO2 layer (MNPs@silica). After that, MIL-101(Fe) as a MOF was synthesized in the presence of MNPs@silica to obtain magnetic MIL-101 (MMIL-101). Finally, MMIL-101(Fe) was functionalized with dithizone as a chelator via diazonation reaction. The nanomaterial fabrication was approved by diverse techniques including, SEM, EDX-mapping, TEM, XRD, FT-IR, VSM, BET, and CHNS. Optimizing of affecting experimental factors on the extraction process was conducted via a Box-Behnken design approach. Determination of the mercury ions was conducted by a cold vapor atomic absorption spectrometer. The LOD and LOQ values were 0.015 µg kg−1 and 0.045 µg kg−1, respectively, and the method's repeatability as RSD% was evaluated for 1.0, 20, and 50 ng mL−1 standard solutions (n = 5), which were 10.1, 7.6, and 4.8 %, respectively. The new method was validated by analyzing a CRM. The maximum adsorption capacity of 213 mg g−1 was obtained, and the preconcentration factor was 316. Finally, the fabricated nanomaterials was successfully utilized to the separation/quantification of mercury in diverse food samples, and satisfactory results were obtained (RSD, 5.9–10.2 %; recovery, 82–112 %).