Chromium Cr Research Articles

SYNTHESIS OF CHROME TANNING AGENT IN PRESENCE OF OLIGO - AND POLYSACCHARIDES

The conditions for the synthesis of chrome tanning agent during the reduction of sodium dichromate with oligo - and polysaccharides have been investigated. The synthesis of the tanning agent is based on the reduction of hexavalent chromium Cr (VI) in the form of sodium dichromate with reducing agents from the class of vegetable oligo- and polysaccharides with a different sequence of their introduction into the reaction mixture in the presence of sulfuric acid. The introduction of sulfuric acid was carried out gradually to avoid overheating and splashing of the reaction mixture, since the reduction reaction is accompanied by a significant thermal effect. Glucose, maltodextrin and pectin were used as reducing agents. The properties of the obtained products were evaluated by spectrophotometry, conductometry, and analytical methods. It has been shown that the use of native pectin leads to the formation of a gel like mass due to the coordination of the functional groups of galacturonic acid, which is part of the pectin, with chromium atoms. Pretreatment of pectin with a citric acid solution and optimization of synthesis conditions made it possible to obtain a chromium tanning agent that does not contain unreduced chromium. The influence of oligosaccharides on the properties of chromium tanning agents, including their ability to dissolve, is considered. It is shown that the reduction of sodium dichromate with maltodextrin during the reaction results in the formation of incomplete oxidation products of the oligosaccharide, which cause the masking effect of the chromium complex and increase in the resistance of the tanning agent to the action of alkaline reagents used to increase in the basicity during tanning. Experimental samples of chrome tanning agent in dry form were obtained and their leatherprocessing characteristics were studied. The results of technological tests have confirmed the theoretical propositions, according to which the high hydrothermal stability of the leather semifinished product, the almost complete depletion of the processing solution and the required physical and mechanical properties of the finished leather are achieved by introducing the products of incomplete oxidation of oligosaccharides into the inner sphere of the chromium complex.

Study on the ecological risk of heavy metals during oily sludge incineration with CaO additive

In order to explore the effect of CaO on the ecological risk of chromium (Cr), copper (Cu) and zinc (Zn) in Oily sludge (OS), the incineration experiments of OS with and without calcium oxide (CaO) additive were carried out respectively in a horizontal tube furnace at the temperature ranging from 800 °C to 1000 °C. Furthermore, the ecological risk based on Risk Assessment Code (RAC) of Cr, Cu and Zn in OS, bottom ash from OS incineration (OSA) and bottom ash from OS incineration in the presence of CaO additive (OSA-CaO) were investigated in this work. The results showed that most of the Cr and Cu in OS remained in bottom ash, while Zn volatilized with the flue gas. At the same time, the RAC of Cr, Cu and Zn in OS decreased significantly after incineration. Compared with OSA, CaO obviously promoted the stabilization of Cr and Cu in OSA-CaO, but had little effect on the behavior of Zn. Moreover, CaO also reduced the RAC of Cu and Zn in samples, and reduced its harm to ecosystem. This study supplied essential data and theoretical support for the industrial treatment of OS, and was of great help to the harmless treatment of OS.

Influence of Non-Lignocellulosic Elements on the Combustion of Treated Wood and Wooden Panel

Brazil stands out internationally in the production and commercialization of wood products. Although the external and internal demand for these products is met by the Brazilian forestry sector, challenges related to the internal management of lignocellulosic waste are evident, as the country has structural difficulties in the sector of solid waste management. Therefore, the objective was to comparatively analyze the performance of the most abundant lignocellulosic materials in the Brazilian market, regarding energy recovery at the end of their life cycles. Pine wood treated with chromed copper arsenate (CCA), untreated pine wood, eucalypt wood treated with CCA, untreated eucalypt wood, uncoated medium density fiberboard panel (MDF), and MDF panel with melamine coating were sampled. The characterization included thermogravimetric analysis (TGA), scanning electron microscopy (SEM) with energy-dispersive x-ray spectroscopy (EDXA), and elementary analysis (EA). The presence of the CCA salts and the melamine coating reduced the energy potential of the biomass, altering the burning behavior and significantly increasing the amount of generated ashes. They also caused an increase in the concentrations of copper (Cu), chromium (Cr), arsenic (As), and cadmium (Cd) in the wood ashes as well as lead (Pb) and chromium in the panel ashes.

Despite higher revision rate, MoM large-head THA offers better clinical scores than HR: 14-year results from a randomized controlled trial involving 48 patients

BackgroundThe high failure rates of metal on metal (MoM) large diameter head total hip arthroplasty (LDH THA) and hip resurfacing (HR) prevented their long-term comparisons with regards to clinical outcome. Such knowledge would be important as ceramic LDH bearing is now available. With long-term follow-up, we investigated the difference in 1) patient-reported outcome measures (PROMs); 2) revision and adverse events rates, and 3) metal ion levels between MoM LDH THA and HR.MethodsForty-eight patients were randomized for LDH THA (24) or HR (24) with the same MoM articulation. At a mean follow-up of 14 years, we compared between groups different PROMs, the number of revisions and adverse events, whole blood Cobalt (Co) and Chromium (Cr) ion levels, and radiographic signs of implant dysfunction.ResultsLDH THA (all cases: revised and well-functioning) had significantly better WOMAC (94 versus 85, p = 0.04), and more frequently reported having no limitation (p = 0.04). LDH THA revision rate was 20.8% (5/24) versus 8.3% (2/24) for HR (p = 0.4). Mean Co and Cr ion levels were higher in LDH THA compared to the HR (Co: 3.8 μg/L vs 1.7 μg/L; p = 0.04 and Cr: 1.9 μg/L vs 1.4 μg/L, p = 0.1). On radiographic analyses, 2 LDH THAs showed signs of adverse reaction to metal debris, whereas 1 loose femoral HR component was documented.ConclusionIn the long-term, MoM LDH THA had a high trunnion related revision rate but nonetheless showed better PROMs compared to HR. Provided with a well-functioning modular junction, non-MoM LDH THA would offer an appealing option.Trial registrationClinicalTrials.gov (NCT04516239), August 18, 2020. Retrospectively registered.

Synthesis of a Stable Benzoxazole Gel from an Imine Gel for Adsorption and Catalysis.

Developing stable gel materials for adsorption and catalysis is one of the major themes of gel materials. However, it has been proven to be challenging to achieve them from small molecules. Herein, an imine gel is developed from tetra-aldehyde 4-{2,2-bis[(4-formylphenoxy)methyl]-3-(4-formylphenoxy)propoxy}benzaldehyde (A4) and 3,3'-dihydroxybenzidine (B2) based on dynamic covalent chemistry. The unstable A4B2-imine gel is further converted into a stable aromatic benzoxazole-linked A4B2-benzoxazole gel via oxidative cyclization, which has significantly improved chemical stability under acidic and basic conditions. Benefiting from the stability under acidic conditions, the A4B2-benzoxazole gel is used for Pd(II) adsorption and the adsorption capacity is 250 mg g-1. After PdCl2 immersion and reduction, palladium nanoparticles with a size distribution of 1.3-14.7 nm are encapsulated by the network structure of the stable porous benzoxazole gel matrix. The Pd@A4B2-benzoxazole gel exhibits high catalytic activity toward the reduction of toxic hexavalent chromium Cr(VI) (reaction rate constant = 0.0377 min-1), while there is no significant decrease in the catalytic efficiency after five cycles.

Assessment of Heavy Metals in Ground Water of Different Locations of National Capital Region, Delhi, India

The quality of ground water in any region of the world entirely depends on different types of chemical constituents and their concentration levels in surrounding environment or dissolved in water. The main aim of this study was to assess some basic hydro-chemical parameters and heavy metals in ground water of National Capital Region (NCR), India. Thus, we have collected ground water samples from different sources viz., Najafargarh (NG), Bindapur (BP), Dwarka (BC and BG), Uttam Nagar (UN) and Sonipat (SP) in the NCR and analyzed electrical conductivity (EC), total dissolved solids (TDS), salinity, Arsenic (As), Chromium (Cr), Copper (Cu), Cadmium (Cd), Nickel (Ni), Zinc (Zn), and Lead (Pb). The values of EC, TDS and salinity across the study sites range from 0.32 to 11.41 mS/cm, 233 to 8100 ppm and 154 to 6310 ppm respectively. Whereas, the mean level of heavy ion concentration in ground water was in the sequence of Zn > Ni > Cr > Pb > As > Cu > Cd across the study sites. It has been concluded that, except for Uttam Nagar, ground water from all study sites is contaminated with heavy metals like Zn, Ni, Cr, Pb and As. Therefore, the ground water from study sites that are polluted is unfit for drinking purpose and may pose health risks.

Elemental Characteristics of Respirable Particulate Matter in the Urban Atmosphere of Dehradun, Uttrakhand, India

To evaluate the ambient air quality of the Dehradun city, respirable particulate matter was collected using respirable dust sampler (RDS) and analysed for the heavy metal content using atomic absorption spectroscopy (AAS). The morphology of particulates were determined using scanning electron microscope (SEM) and the elemental composition was determined through SEM- energy dispersive spectroscopy (EDS). Particulate matter mass concentration ranged from 65.00 µg m-3 to 337.33 µg m-3. Quantified heavy metals in particulate matter were Copper (Cu), Zinc (Zn), Cobalt (Co), Manganese (Mn), Iron (Fe), Nickel (Ni), Chromium (Cr), Lead (Pb) and Cadmium (Cd). The order of concentration of heavy metals were found to be in the trend of Fe>Zn>Cu>Pb>Cr>Ni>Mn>Co>Cd. Maximum concentration of PM10 was found at commercial site during summer, winter and monsoon season. Enrichment factor analysis showed substantial contribution of anthropogenic activities on PM10. Source apportionment (varimax rotated factor analysis method) showed dominance of incineration and uncontrolled burning of waste and refuses, resuspended dust with vehicular emission and crustal sources as the dominant sources in Dehradun. Plantation drive strategy have major role in ambient particulate matter mitigation measures and carbon sequestration from climate change and global problem worldwide. This study will be help to mitigate or decrease the load of air pollution by the using of various trees for sustainable human development on the marvellous earth planet.

Application of Factorial Design for the Optimization of Hexavalent Chromium Removal Using a New Low-cost Adsorbent: Adsorption Isotherms, Thermodynamic and Kinetic Studies

This research work involved using factorial experimental design techniques to investigate the adsorption of hexavalent chromium from an aqueous solution on medlar activated carbon. A 24 full factorial experimental design was employed to determine the optimum values and degree of importance of parameters: pH, initial Cr (VI) concentration, adsorbent dose, and contact time at two levels. The optimized conditions for hexavalent chromium Cr (VI) removal were at initial pH 1.5, 5 mg.L−1Cr (VI), adsorbent dose 6 mg, and 60 min adsorption time. The results predicted a good agreement between the predicted values (R2= 0.9909), as obtained by the model, and the experimental value (R2= 0.9977). The main effects and interaction effects were analyzed using analysis of variance (ANOVA), F-test and P-values to define the most important process variables affecting Cr (VI) adsorption. The most significant variables were therefore the pH of the solution and the adsorbent dose. Therefore, the present results demonstrate that medlar activated carbon should be regarded as a low-cost alternative for removing Cr (VI) from an aqueous solution. The adsorption data were evaluated by Langmuir, Freundlich, and Dubinin-Radushkevich isotherms. The results showed that the Langmuir isotherm model best describes the equilibrium adsorption with a high correlation coefficient.

Decoration of serpentine with iron ore as an efficient low-cost magnetic adsorbent for Cr (VI) removal from tannery wastewater

In this paper, a dry particle-particle coating technique was implemented to develop magnetic adsorbent from natural mineral constituents. Iron ore, specifically banded iron formation (BIF), was used as guest magnetic particles while serpentine (Serp) was used as host adsorptive material. Surface characterizations for the synthesized composite were investigated. The results confirmed the formation of a composite that combines both magnetic and adsorptive properties. The capability of the composite for hexavalent chromium Cr(VI) removal was investigated under different conditions. A maximum adsorption capacity of 138 mg/g was achieved. The adsorption of Cr(VI) onto the magnetic composite (BIF@Serp) was further thermodynamically and kinetically investigated. The results indicated that the adsorption follows 1.2-order kinetics and occurs spontaneously with an exothermic nature. Application of BIF@Serp for the treatment of real tannery effluent was conducted, the composite showed an excellent removal performance not only with Cr(VI) but also with other heavy metals and organic contaminants.

Biosorption of hexavalent chromium and Congo red dye onto Pleurotus mutilus biomass in aqueous solutions

With the significantly increasing pharmaceutical and antibiotics industry in Algeria, the elimination of biomass is of utmost importance since the latter represents a large part of waste from the manufacturing process. In this work, the elimination of hexavalent chromium Cr (VI) and Congo red dye is part of the Pleurotus mutilus biomass recovery process. Thus, biosorption has been studied in a discontinuous system. Optimal conditions were estimated by variations in contact time, temperature, initial pollutant concentrations, and simultaneous removal of both pollutants. The greatest uptake capacities achieved were 36.68 mg/g of and 15.08 mg/g of Cr(VI). The initial concentrations of both pollutants being equal to 50 mg/l, for a duration time of 180 min and a temperature of 300 K. Based on the values of the coefficient of determination R2, χ2, and ARE, the isothermal equilibrium data were better represented by Freundlich, Temkin, and Dubinin-Radushkevich models. The kinetic biosorption of the two pollutants was well described using the pseudo-first-order model. The biosorption process is controlled by external mass transfer. The physical process in nature of Cr(VI) and (CR) biosorption has been justified based on the values obtained of ΔG° and ΔH°. Globally, this work demonstrates the considerable potential of Pleurotus mutilus for the elimination of anionic pollutants. Research results indicate that this biomass, a waste material, first destined for incineration, was recovered without any treatment. Due to its low cost, it could serve as an inexpensive source for recovering heavy metals and dyes from dilute contaminated water.

Concentrations and health risks assessment of heavy metals in cigarettes within Baghdad city

The risks associated with smoking can be due to the inhalation of toxic substances like heavy metals and polycyclic aromatic hydrocarbons (PAHs) that can be released during tobacco burns. In the present study we measured lead Pb and three other metals (cadmium Cd; Chrome Cr; and Zinc Zn) by flame atomic absorption spectroscopy (FAAS). In a twenty-five brands of cigarettes, assessing potential related health risks estimated intakes of these metals. The Related Cancer Risk (RCR) and Average Daily Intake (ADI) were calculated. The results revealed that the average values of Pb, Cd, Cr and Zn concentrations were (4.56, 0.39, 3.31 and 1.36) μg/g respectively. The total value of these four metals is greater than the range of cancer risk specified by USEPA. Â

The Effect of Chromium on Photosynthesis and Lipid Accumulation in Two Chlorophyte Microalgae

Heavy metals have adverse effects on microalgae metabolism and growth. Photosynthesis and lipid profile are quite sensitive to heavy metal toxicity. The impact of hexavalent chromium—Cr(VI) on photosynthesis and lipid accumulation in Mucidosphaerium pulchellum and Micractinium pusillum exposed to different concentrations (0–500 μg L−1) was investigated for 11 days. A significant (p < 0.05) increase in lipid content was observed with increasing Cr(VI) concentration. However, growth was suppressed at higher concentrations exceeding 100 μg L−1. Addition of Cr(VI) in the cell culture medium showed a negative effect on quantum yield (Fv/Fm), and a photosynthetic inhibition of >65% was noted in both species at 500 μg L−1. However, the lipid gravimetric analysis presented inner cell lipid content up to 36% and 30% of dry weight biomass for M. pulchellum and M. pusillum, respectively. The fatty acids profiles of both microalgae species showed higher levels of hexadecenoic acid as well as ω3, ω6, and ω7 fatty acids. The effect of Cr(VI) on photosynthesis and lipid accumulation in both microalgae species was concentration and exposure time dependent. This shows that an appropriate concentration of Cr(VI) in culture medium could be beneficial for higher lipid accumulation in freshwater eukaryotic microalgae species.

Benchmarking the Fluxional Processes of Organometallic Piano-Stool Complexes.

The correlation consistent Composite Approach for transition metals (ccCA-TM) and density functional theory (DFT) computations have been applied to investigate the fluxional mechanisms of cyclooctatetraene tricarbonyl chromium ((COT)Cr(CO)3) and 1,3,5,7-tetramethylcyclooctatetraene tricarbonyl chromium, molybdenum, and tungsten ((TMCOT)M(CO)3 (M = Cr, Mo, and W)) complexes. The geometries of (COT)Cr(CO)3 were fully characterized with the PBEPBE, PBE0, B3LYP, and B97-1 functionals with various basis set/ECP combinations, while all investigated (TMCOT)M(CO)3 complexes were fully characterized with the PBEPBE, PBE0, and B3LYP methods. The energetics of the fluxional dynamics of (COT)Cr(CO)3 were examined using the correlation consistent Composite Approach for transition metals (ccCA-TM) to provide reliable energy benchmarks for corresponding DFT results. The PBE0/BS1 results are in semiquantitative agreement with the ccCA-TM results. Various transition states were identified for the fluxional processes of (COT)Cr(CO)3. The PBEPBE/BS1 energetics indicate that the 1,2-shift is the lowest energy fluxional process, while the B3LYP/BS1 energetics (where BS1 = H, C, O: 6-31G(d′); M: mod-LANL2DZ(f)-ECP) indicate the 1,3-shift having a lower electronic energy of activation than the 1,2-shift by 2.9 kcal mol−1. Notably, PBE0/BS1 describes the (CO)3 rotation to be the lowest energy process, followed by the 1,3-shift. Six transition states have been identified in the fluxional processes of each of the (TMCOT)M(CO)3 complexes (except for (TMCOT)W(CO)3), two of which are 1,2-shift transition states. The lowest-energy fluxional process of each (TMCOT)M(CO)3 complex (computed with the PBE0 functional) has a ΔG‡ of 12.6, 12.8, and 13.2 kcal mol−1 for Cr, Mo, and W complexes, respectively. Good agreement was observed between the experimental and computed 1H-NMR and 13C-NMR chemical shifts for (TMCOT)Cr(CO)3 and (TMCOT)Mo(CO)3 at three different temperature regimes, with coalescence of chemically equivalent groups at higher temperatures.

Proteomic responses of maize roots to the combined stress of sulphur deficiency and chromium toxicity

Sulphur (S) metabolism plays a crucial role in response to heavy metal stress. It has been well demonstrated that the deficiency of S is a limiting factor to plant capability to cope with chromium (Cr) stress. However, little is known about the plant response to S-deficiency and Cr stress at the proteome level. In the present study, a hydroponic experiment was conducted to examine the role of S supply on Cr-induced proteomic alterations in the roots of maize seedlings. Maize seedlings were exposed to Cr (0 and 100 μM) and different S concentrations (0 and 1 mM) for seven days. Biomass accumulation (fresh and dry weights) was significantly decreased by Cr stress (100 μM), and this decrease was more pronounced under S-deficiency condition. Analysis of proteins on gels detected 54 proteins that exhibited differential expression patterns, out of which 38 were identified by matrix-assisted laser desorption ionization time-of-flight/ time-of-flight (MALDI-TOF/TOF) mass spectrometry. Of these, 21 proteins were up-regulated and 17 proteins were down-regulated by >1.5-fold S-deficiency and/or under Cr stress. The majority of the proteins functioned in stress defence, protein metabolism, and energy metabolism. Our results show that S supplementation enhanced the tolerance to Cr stress by increasing the abundance of stress defence-related proteins including pathogenesis-related protein 10, glutathione peroxidase, superoxide dismutase [Mn], glutathione S-transferase 3, proteasome subunit alpha type 6, IN2–1 protein, and ABA-responsive protein. This study may provide new insights into the proteomic response mechanisms of maize seedlings under Cr stress and/or S-deficiency.

Factors Affecting the Hardness Characteristics of Microstructures in Gas Carburized Chromium Alloy Steels

We analyzed the factors affecting the gas carburizing microstructure of parts for constant velocity joints. Gas carburizing 0.15-0.20C1.13-1.14Cr chromium alloy steel used in automobile drive units is characterized by changing the properties of the carburizing layer in the depth direction.
 The experimental conditions were set to enable field application. The components of the specimen to be used for gas carburization were analyzed by X-ray fluorescence. Changes in the mechanical properties of the carburized layer were analyzed by micro-hardness, microstructure, and carburizing content. The gas carburization cycle was selected based on the simulation results. The characteristics change before and after carburization of two samples with different carbon and chromium content were analyzed.
 The carburization temperature that can be used for manufacturing automobile parts was 930°C, the carbon potential required for carburization was 0.90wt%, and the carbon potential required for diffusion was 0.75wt%. The inner and outer hardness values of the carburized layer satisfying the effective hardening depth of 550Hv were 400Hv-740Hv. In the case of 0.20C alloy steel, the effective hardening depth with a carburizing amount of 0.36wt% and a hardness of 550Hv was 1.467 mm. also in the case of 0.15C steel, its effective hardening depth was 0.746 mm. The simulation results for selecting the carburizing heat treatment conditions and the carbon change in the carburizing layer showed a similar trend. The carburizing structure related to hardness change was martensite. As a result of EPMA, SEM, and XRD analysis, the amount of carburized and the amount of martensite structure correlated, and the martensite increased as the amount of carburized increasing. As a result of EPMA analysis, the smaller the carburizing content the greater the depth of carburization.
 We intend to proceed with optimization conditions for mass production in connection with wear resistance and fatigue. It is expected that these results will contribute to the improvement of durability of automobile driving parts.

The Spectrophotometric Determination of Chromium (vi) Using N, N-diethyl-p-phenylenediamine in Synthetically Prepared Wastewater, And Tap Water

The DPD (N, N-diethyl-p-phenylenediamine) is introduced in the present study as an analytical reagent for the direct, rapid, easy, and sensitive spectrophotometric detection of hexavalent chromium Cr (VI) species which is health hazard. The oxidization of the colorless DPD (N, N-diethyl-p-phenylenediamine) reagent with Cr (VI) results in a red color DPD radical (DPD•+) at pH 4.39. The color intensity is directly proportional to the Cr (VI) concentration. By utilizing a UV-Vis spectrophotometer, the measurement of the produced DPD•+ can be identified in term of quantity at 551 nm. The linear calibration graphs for 0.2 – 2 mg. L−1 of Cr (VI) are obtained with a correlation coefficient value of 0.9997. The molar absorption coefficient and Sandell's sensitivity are 2.5449x104 L.mol−1cm−1and 0.028 mg. Cr (VI), cm−2, respectively. The present work develops, optimizes, and validates a new spectrophotometric method for determining Cr (VI) in the samples of the synthetically prepared wastewater and tap water. The method is effectively applied and the findings are statistically evaluated with those of the reference method.

Identification of metal binding motifs in protein frameworks to develop novel remediation strategies for Hg2+ and Cr(VI).

Amino acid sequences in metal-binding proteins with chelating properties offer exciting applications in biotechnology and medical research. To enhance their application in bioremediation studies, we explicitly aimed to identify specific metal-binding chelating motifs in protein structures for two significant pollutants, such as mercury (Hg2+) and chromium Cr(V1). For this purpose, we have performed an extensive coordination chemistry approach by retrieving Hg2+ and Cr(V1) binding protein structures from the protein database and validated using the B-factor, a term defining uncertainty of the atoms and with occupancy to obtain the best binding motifs. Our analysis revealed that acidic amino acids like aspartic acid, glutamic acid, and basic amino acids such as cysteine and histidine are predominant in coordinating with these metals. The order of preference in Hg2+-bound structures is predicted to be Cys > His > Asp > Glu, and for Cr(V1) is His > Asp > Glu. Examination of the atomic coordinates and their distance from each metal revealed that the sulfur atoms of cysteine showing more preference towards Hg2+coordination with an atomic distance ranging from 1.5 to 2.9Å. Likewise, oxygen atoms of aspartic acid, glutamic acid and nitrogen atoms of histidine are within 2Å of Cr(V1) coordination. Based on these observations, we obtained C-C-C, C-X(2)-C-C-(X)2-C, H-C-H motifs for Hg2+, and D-X(1)-D, H-X(3)-E motif for Cr(V1) to be shared within the coordination space of 3Å. As a future scope, we propose that the identified metal-binding chelating motifs are oligopeptides and can display on the surface of microorganisms such as Escherichia coli and Saccharomyces cerevisiae for effective removal of natural Hg2+ and Cr(V1) through biosorption. Hence, our results will provide the basis for futuristic bioremediation.

Heavy metal contamination of topsoil in Denizli Organized Industrial Zone, Western Anatolia, Turkey

This paper deals with determination of the environmental pollution in Denizli Organized Industrial Zone and its surroundings. Denizli is one of the biggest industrial cities of Turkey hosting several factories with immense production, regularly shipped by a vast haulage system. The study area is traversed by one of the most crowded highways in the country, ensuring the transportation between Western and Central Anatolia. It is also traversed by a railroad connecting Denizli city to Izmir city located on the Aegean Sea coast. Therefore, covering an area of about 30 km2, 154 samples were collected to be subject of the magnetic susceptibility measurements end up at highlighting contaminated zones in the study area. The spatial distribution maps plotted for both magnetic susceptibility measurements acquired at high (χHF) and low (χLF) frequencies showed coherent anomalies following the direction of the roads (east-west). According to the magnetic susceptibility measurements, 40 initial samples were chosen to be chemically analysed by X-ray fluorescence (XRF) analysis. The soil nature was determined by examining 10 supplementary samples collected from the study area. Concentrations of copper (Cu), lead (Pb), nickel (Ni), chromium (Cr), zinc (Zn), and iron (Fe) and magnetic parameters were statistically analysed for the best understanding of the correlation of the heavy metal pollution and magnetic susceptibility values. The environmental status of the study area was evaluated by the aid of elaboration and interpretation of the contamination factor (CF), geoaccumulation index (Igeo), enrichment factor (EF), and the pollution load index (PLI) which allowed the comparison between the different polluted parts of the study area. The results obtained as maximum values from the calculation of the contamination factor were found as follows: Cr (31.12), Ni (12.88), Fe (11.42), Cu (11.20), Zn (4.71), and Pb (2.87). The maximum values obtained for the implemented geoaccumulation index were found for each element as follow: Cr (4.37), Ni (3.1), Fe (2.93), Cu (2.9), Zn (1.65), and Pb (0.9), while the enrichment factor’s results were found as follow: Fe (2.93), Cr (4.37), Ni (3.10), Zn (1.65), Cu (2.90), and Pb (0.93). Results showed that the Tomlinson pollution load index (PLI) calculated for the six elements is reflecting a heavy pollution of the study area by reaching the value of 6.41 as a mean of the total analysis results and 11 as a maximum value. The magnetic susceptibility and heavy metals distribution showed similar anomaly locations especially out of the area of Denizli organized industrial zone which seems to be less contaminated giving a sign of the liberation of industrial wastes into the surrounding areas. The farming lands were also found to be acting in the enrichment of the heavy metal content in the study area soils. The main anomalies introduce the contamination of the lower zones of the study area which is the result of the transportation of anthropogenic pollutants by wind and stream. Considering the study results, it is recommended to regularly evaluate the environmental status of the study area in order to prevent irremediable diseases.

Spectrophotometric determination of cadmium, chromium, lead and nickel in five selected body creams sold in Benin City, Nigeria

The concentrations of cadmium (Cd), chromium (Cr) lead (Pb), and nickel (Ni) were evaluated in five body creams sold in different shopping malls and markets in Benin City metropolis. The samples were classified into bleaching creams, toning creams and moisturizers. The moisture content of each cream sample was determined using standard methods while the heavy content was obtained using atomic absorption spectrometry (AAS). Pb was found to have the highest concentration in bleaching cream 2 (9.70 ppm) and the lowest in moisturizer 1 (1.50 ppm). The concentration range for Cd was from 9.20 ppm in moisturizer 2 to 2.90 ppm in the toning cream. The highest concentration of Ni was found in moisturizer 1 (7.00 ppm) and the lowest was in bleaching cream 2 (1.20 ppm). Cr was not detected in the bleaching and toning creams but it was found to be 26.00ppm in moisturizer 1. The results were compared with international standards and were found to be within the limits set by the cosmetic standards of USA, Canada and WHO. The results from this study has shown that the use of these body creams exposes users to some level of concentration of these toxic metals which could constitute potential health hazard due to their ability to bio-accumulate. Therefore, there should be regular monitoring of heavy metals and other chemicals used in the manufacture of body creams.

Monitoring of heavy metal pollution in urban and rural environments across Pakistan using House crows (Corvus splendens) as bioindicator.

A widely distributed urban bird, the house crow (Corvus splendens), was used to assess bioavailable heavy metals in urban and rural environments across Pakistan. Bioaccumulation of arsenic (As), zinc (Zn), lead (Pb), cadmium (Cd), nickel (Ni), iron (Fe), manganese (Mn), chromium (Cr), and copper (Cu) was investigated in wing feathers of 96 crows collected from eight locations and categorized into four groups pertaining to their geographical and environmental similarities. Results revealed that the concentrations of Pb, Ni, Mn, Cu, and Cr were positively correlated and varied significantly among the four groups. Zn, Fe, Cr, and Cu regarded as industrial outputs, were observed in birds both in industrialized cities and in adjoining rural agricultural areas irrigated through the Indus Basin Irrigation System. Birds in both urban regions accrued Pb more than the metal toxicity thresholds for birds. The house crow was ranked in the middle on the metal accumulation levels in feathers between highly accumulating raptor and piscivore and less contaminated insectivore and granivore species in the studied areas,. This study suggests that the house crow is an efficient bioindicator and supports the feasibility of using feathers to discriminate the local pollution differences among terrestrial environments having different levels and kinds of anthropogenic activities.