Mg Of Cr Research Articles

Determination of chromium picolinate and trace hexavalent chromium in multivitamins and supplements by HPLC-ICP-QQQ-MS

Chromium picolinate (CrPic) and trace hexavalent chromium (Cr(VI)) content were characterized in VITA-1 and VITB-1, two new multivitamin and mineral supplement candidate reference materials from National Research Council Canada, by two methods of high performance liquid chromatography inductively-coupled plasma triple quadrupole mass spectrometry. The conditions for the separation of Cr(VI) from EDTA-complexed Cr(III) were optimized such that species interconversions were not observed during analysis. Following extraction with dilute NH4OH in water at pH 10 (for Cr(VI)) or 3:2 acetonitrile:water (for CrPic) and quantification by standard addition, it was concluded that CrPic accounted for 95–96 % of the Cr in VITA-1 and VITB-1, while Cr(VI) was not present above the detection limit of 0.13 μg Cr g−1. Using the two developed methodologies, commercially-available nutritional supplements, in the form of vitamin tablets and dried food supplements, were assessed, and it was determined that CrPic accounted for the majority (92 %–98 %) of the chromium present in the tablets, and that Cr(VI) concentrations were below the detection limit for all samples except for the powdered beets where it accounted for nearly half of the total Cr present.

Hexavalent chromium reduction ability and bioremediation potential of Aspergillus flavus CR500 isolated from electroplating wastewater

Hexavalent chromium reduction by microbes can mitigate the chromium toxicity to the environment. In the present study Cr[VI] tolerant fungal isolate (CR500) was isolated from electroplating wastewater, was able to tolerate 800 mg/L of Cr[VI. Based on the ITS region sequencing, the isolate was identified as Aspergillus flavus CR500, showed multifarious biochemical (reactive oxygen species, antioxidants response and non-protein thiol) and morphological (protrusion less, constriction and swelling/outwards growth in mycelia) response under Cr[VI] stress. Batch experiment was conducted at different Cr[VI] concentration (0–200 mg/L) to optimize the Cr[VI] reduction and removal ability of isolate CR500; results showed 89.1% reduction of Cr[VI] to Cr[III] within 24 h and 4.9 ± 0.12 mg of Cr per gram of dried biomass accumulation within 144 h at the concentration of 50 mg/L of Cr[VI]. However, a maximum of 79.4% removal of Cr was recorded at 5 mg/L within 144 h. Fourier-transform infrared spectroscopy, energy dispersive x-ray spectroscopy and X-ray diffraction analysis revealed that chromium removal also happened via adsorption/precipitation on the mycelia surface. Fungus treated and without treated 100 mg/L of Cr[VI] solution was subjected to phytotoxicity test using Vigna radiata seeds and result revealed that A. flavus CR500 successfully detoxified the Cr[VI] via reduction and removal mechanisms. Isolate CR500 also exhibited efficient bioreduction potential at different temperature (20–40 °C), pH (5.0–9.0), heavy metals (As, Cd, Cu, Mn, Ni and Pb), metabolic inhibitors (phenol and EDTA) and in sterilized tannery effluent that make it a potential candidate for Cr[VI] bioremediation.

Ecuadorian yeast species as microbial particles for Cr(VI) biosorption.

Pollution caused by heavy metals is a prime concern due to its impact on human health, animals, and ecosystems. Cr(VI), generated in a range of different industries as a liquid effluent, is one of the most frequent contaminants. In the work presented herein, the adsorption efficiency of three species of native yeasts from Ecuador (Kazachstania yasuniensis, Kodamaea transpacifica, and Saturnispora quitensis) for Cr(VI) removal from simulated wastewater was assessed, taking Saccharomyces cerevisiae as a reference. After disruption of the flocs of yeast with a cationic surfactant, adsorption capacity, kinetics, and biosorption isotherms were studied. K. transpacifica isolate was found to feature the highest efficiency among the four yeasts tested, as a result of its advantageous combination of surface charge, individual cell size (4.04 μm), and surface area (1588.27 m2/L). The performance of S. quitensis was only slightly lower. The remarkable biosorption capacities of these two isolates (476.19 and 416.67 mg of Cr(VI)/g of yeast, respectively) evidence the potential of non-conventional yeast species as sorption microbial particles for polluted water remediation.

Electrolyte-based Carbohydrate Drink: Effect On Steady State Exercise Done Against Progressively Higher Workloads

Aerobic exercise with progressively higher workload stages done in succession challenges a person’s cardiorespiratory system as their VO2max is estimated. Higher heart rates (HR) at the end of stages lowers a person’s estimated VO2max. Adding electrolytes to a carbohydrate-based drink may raise VO2max values if ingested before exercise. PURPOSE: Compare the merits of added electrolytes, in two otherwise similar beverages, when consumed before VO2max tests that entail progressively higher workload stages stages. METHODS:In a randomized double-blind study subjects (13 men, 21 women) first gave written informed consent, followed by two stationary cycle ergometer workouts to estimate their VO2max. Workouts were preceded by intake of a 2% sucrose solution, one of which was an electrolyte-rich (500 mg of vitamin C, 1 mg of B-12, 100 mg of Mg+2, 400 mg of K+, 200 mg of Na+, 1 μg of Cr) beverage, while the other was devoid of added electrolytes and served as a placebo. HR were recorded before, four times during, and after workouts. Ratings of perceived exertion (RPE) were provided at the end of workouts. HR were compared with a three-way (gender, treatment, time) ANOVA, with repeated measures for treatment and time. Estimated VO2max and RPE were assessed with two-way (gender, treatment) ANCOVAs, with repeated measures for treatment. Body mass and body fat percentage were examined as covariates. Scheffe’s served as our post-hoc and a α= 0.05 denoted significance. RESULTS:There were significant inter-time differences for HR. RPE and VO2max each had inter-gender differences. Yet there were no inter-treatment differences. CONCLUSIONS:Little research exists on the ergogenic effects on electrolyte formulations added to carbohydrate beverages, yet our results concur with studies that also saw a lack of inter-treatment differences.

Cr(VI) and Cr(III) in milk, dairy and cereal products and dietary exposure assessment

ABSTRACTMilk, dairy and cereal products are the main contributors to total chromium (Cr) dietary exposure in France (up to 42% for children), but there have been no assessments regarding dietary exposure to Cr(VI) or Cr(III) to date. To assess dietary exposure, total chromium and Cr(VI) were determined in 68 different brands and origins of milk, dairy and cereal products. Cr(VI) was not detected in these samples despite the very high sensitivity of the method used. It was therefore assumed that total chromium is only present in the Cr(III) form. Total chromium levels were quantified in 58% of milk and dairy products and 76% of cereal products. The highest mean levels were found in breakfast cereals and cheese (269 and 25 µg Cr /kg fresh weight, respectively). The findings pointed out that the dietary exposure levels of Cr(III) and Cr(VI) were well below the health-based guidance values.

Determination of hexavalent Cr in river sediments by speciated isotope dilution inductively coupled plasma mass spectrometry

During a sampling campaign in September 2015, elevated chromium (Cr) concentrations were observed in sediments of industrially exposed sites of the Sava River (stainless steel production and impact of metallurgic industry). To verify if sediments also contained hazardous hexavalent Cr (Cr(VI)), there was a need to develop a sensitive and reliable analytical procedure for its determination. In the determination of Cr(VI) in environmental samples, it is necessary to evaluate the suitability of the applied analytical methodology for each individual sample matrix. In these studies, the use of isotopically enriched Cr tracers importantly contribute to the validity of the obtained results. In the present work, an analytical procedure was optimised for the extraction of total Cr(VI) from sediments and the content of Cr(VI) determined by high performance liquid chromatography coupled to inductively coupled plasma mass spectrometry (HPLC-ICP-MS). To leach the total amount of Cr(VI) from sediments, an ultrasound-assisted extraction procedure was applied at 80 °C, using 2% NaOH + 3% Na2CO3 as the extraction solution. The addition of 0.4 mol L−1 MgCl2 prevented oxidation of Cr(III) during the extraction step. To control for species interconversion and for an accurate calculation of Cr(VI) concentration by speciated isotope dilution (ID)-ICP-MS, the alkaline extract was doubly spiked with enriched 50Cr(VI) and 53Cr(III). The accuracy of the determination of Cr(VI) was verified by analysing the certified reference material CRM 041 (Cr(VI) in soil), and by spike recovery test. Low limits of detection (LOD) and quantification (LOQ) (1.25 and 4.0 μg Cr(VI) kg−1, respectively) and good repeatability of measurement (relative standard deviation better than ±4.8%) were obtained. The analytical data revealed that Cr(VI) concentrations in sediments of the Sava River did not represent any known environmental hazard.

A Robust Method for the Determination of Cr(VI) and Cr(III) in Industrial Wastewaters by Liquid Chromatography-Inductively Coupled Plasma Mass Spectrometry Combined with a Chelating Pretreatment with 2,6-Pyridinedicarboxylic Acid.

We have developed a method for the determination of Cr(VI) and Cr(III) in industrial wastewater by liquid chromatography-inductively coupled plasma mass spectrometry (LC-ICP-MS) combined with a chelating pretreatment with 2,6-pyridinedicarboxylic acid (PDCA). The PDCA unified the chemical forms of the Cr(III) species in water samples by the formation of a stable Cr(III)-PDCA complex, which was then separated by a LC column. The chromatographic mobile phase at neutral pH and the column of a mixed-bed of anion and cation exchangers successfully separated not only the chromium species without any redox conversion, but also chloride, which interfered with ICP-MS detection. The method detection limits measured at m/z 53 were 0.66 μg of Cr L-1 for Cr(III) and 0.74 μg L-1 for Cr(VI) with a sample injection volume of 20 μL under a no gas mode. The recoveries of spiked Cr(VI) at 50 and 500 g L-1 into the fifteen kinds of industrial wastewater samples were satisfactory (>90%). The proposed method for the determination of Cr(VI) was also validated by comparing with a colorimetric method using 1,5-diphenylcarbazide prescribed by the ISO 11083 and the JIS K0102.

Analysis of Biosorption Parameters, Equilibrium Isotherms and Thermodynamic Studies of Chromium (VI) Uptake by a Nostoc sp. Isolated from a Coal Mining Site in Meghalaya, India

A cyanobacterium isolated from a water sample collected from a coal mine in the West Khasi Hills of Meghalaya, India, and identified as Nostoc sp. (accession no. KX814344) using 16S rRNA analysis showed a high tolerance to chromium. It was shown to be able to grow in the presence of 15 ppm Cr, which is 30 times the highest Cr concentration recorded in the area. Cr biosorption by the cyanobacterium was optimum at pH 6.0 with 3 µg mL−1 biomass. The sorption showed a linear correlation with increasing metal concentration, gradually reaching saturation. An energy dispersive X-ray study verified Cr binding on the cyanobacterial biomass, and FTIR analysis revealed many negatively charged functional groups on the cell surface, which aided in metal binding. Thermodynamic studies showed the biosorption process to be energetically favorable: − 0.479, − 0.665, and − 0.852 kJ mol−1 at temperatures of 293, 303, and 313K, respectively. Sorption isotherm data fit the Langmuir isotherm best, indicating the monolayer nature of the Cr sorption. The organism’s maximum sorption capacity was as high as 20 mg of Cr per g of biomass. The separation factor calculated from the Langmuir isotherm was < 1, signifying favorable interaction between the cyanobacterial biomass and the Cr ions.

Hexavalent chromium removal from municipal wastewater using ferrous salts

Abstract Hexavalent chromium is difficult to remove during conventional biological wastewater treatment. This is because the hexavalent form is dissolved and is only sparingly removed by adsorption onto biomass in conventional processes. Hexavalent chromium is of particular concern because of its aquatic toxicity, and an increasing number of wastewater works have effluent discharge limits to protect receiving water courses, some as low as 8 μg Cr L−1. A relatively simple improvement to the removal of chromium could be made by switching the aluminium or ferric solution dosed at most treatment works for the removal of solids, organic load and phosphorus, to a ferrous salt. Ferrous reduces hexavalent chromium to insoluble trivalent chromium, which can be readily settled out of waste streams as a particulate. In the present study, laboratory experiments using real wastewater and ferrous doses of 10 mg Fe L−1 achieve the chromium discharge consent of 8 μg L−1 from initial solution concentrations of up to 40 μg L−1. A ferrous chloride dosing system was subsequently installed at an operational sewage treatment works that has produced an average final effluent chromium concentration of 2.4 μg L−1 (with a maximum of 4.2 μg L−1), despite influent spikes &amp;gt;300 μg L−1.

Two combined mechanisms responsible to hexavalent chromium removal on active anaerobic granular consortium

Hexavalent chromium (Cr VI) from industrial wastewaters represents a highly toxic source at low concentrations. Biological treatments with anaerobic granular biomass are a promising alternative for the Cr VI bioremediation. This study evaluated the Cr VI removal in a range of 5–500 mg/L, using an active anaerobic granular consortium. Two removal mechanisms were differentiated from the assays: 1) biological reduction of 70 mg/L to Cr III at a concentration of 250 mg Cr VI/L and 2) physical bioadsorption of 297 mg of Cr VI/L or 31.39 mg of Cr VI/gbiomass at concentration of 500 mg Cr VI /L. The half-maximal inhibitory concentration (IC50) values for the rate and production of methane were 1.4 and 253 mg/L, respectively. In addition, Cr VI is a biostimulant that increase the methane production, in a range from 5 to 100 mg/L, of the anaerobic consortium. This work demonstrates the potential application of the anaerobic granular consortium in metal bioremediation.

Characterization of Penicillium oxalicum SL2 isolated from indoor air and its application to the removal of hexavalent chromium.

Removal of toxic Cr(VI) by microbial reduction is a promising approach to reducing its ecotoxicological impact. To develop bioremediation technologies, many studies have evaluated the application of microorganisms isolated from Cr(VI)-contaminated sites. Nonetheless, little attention has been given to microbes from the environments without a history of Cr(VI) contamination. In this study, we aimed to characterize the Cr(VI) tolerance and removal abilities of a filamentous fungus strain, SL2, isolated from indoor air. Based on phenotypic characterization and rDNA sequence analysis, SL2 was identified as Penicillium oxalicum, a species that has not been extensively studied regarding Cr(VI) tolerance and reduction abilities. SL2 showed high tolerance to Cr(VI) on solid and in liquid media, facilitating its application to Cr(VI)-contaminated environments. Growth curves of SL2 in the presence of 0, 100, 400, or 1000 mg/L Cr(VI) were well simulated by the modified Gompertz model. The relative maximal colony diameter and maximal growth rate decreased as Cr(VI) concentration increased, while the lag time increased. SL2 manifested remarkable efficacy of removing Cr(VI). Mass balance analysis indicated that SL2 removed Cr(VI) by reduction, and incorporated 0.79 mg of Cr per gram of dry biomass. In electroplating wastewater, the initial rate of Cr(VI) removal was affected by the initial contaminant concentration. In conclusion, P. oxalicum SL2 represents a promising new candidate for Cr(VI) removal. Our results significantly expand the knowledge on potential application of this microorganism.

Interactive Effects of EDTA and Oxalic Acid on Chromium Uptake, Translocation and Photosynthetic Attributes in Indian Mustard (&lt;i&gt;Brassica juncea&lt;/i&gt; L. var. Varuna)

The accumulation and toxicity of chromium (Cr) in Indian mustard ( Brassica juncea L.) under ethylene diamine tetraacetic acid (EDTA) and oxalic acid (OA) as chelating agents was studied. Plants were exposed to Cr(VI) and chelating agents in four experimental set-ups as Cr(VI), Cr(VI) + EDTA (1 : 1), Cr(VI) + OA (1 : 1) and Cr(VI) + EDTA + OA (1 : 1 : 1), where each set-up comprised of 0, 6.25, 12.5 and 25.0 mg of Cr(VI) and/or chelating agents in 250 g of soil. Results conferred that EDTA augmented bio-concentration factor in all the three doses of Cr(VI), OA considerably increased translocation factor in all the treatments, including control, and the combined application of the two chelates escalated both the aforesaid factors. Moreover, these chelating agents help in ameliorating Cr(VI) toxicity asserted by low degree of lipid peroxidation, insubstantial damage in root and shoot length, fresh and dry biomass, chlorophyll and leaf gas exchange parameters. Besides, plants showed a robust detoxification mechanism primarily by significant (P < 0.05) production of reduced glutathione and phytochelatins among other enzymatic and nonenzymatic antioxidants under these chelating agents. The present findings suggest that Indian mustard could be used as a potential phytoremediator of Cr(VI) under the combined application of EDTA and OA.

EFFECT OF SUPPLEMENTING DIET WITH SODIUM BENTONITE AND/OR ORGANIC CHROMIUM ON PRODUCTIVE, PHYSIOLOGICAL PERFORMANCE AND IMMUNE RESPONSE OF MATROUH CHICKENS STRAIN. 1- DURING GROWTH PERIOD.

The main objective of this study was to investigate the effect of sodium bentonite (Na-B) (0, 5 and 10 g/kg diet) and chromium picolinate (CrPic) (0, 800 and 1200 µg Cr /kg diet) in the diet on growth performance, the mortality rate; some blood serum constituents, as well as the immune response and economic efficiency of male chicks of local strain Matrouh during the growing period. 540 one-day old male chicks were randomly chosen from a flock reared on the floor and distributed into 9 treatment groups (60 males / each treatment) in a factorial arrange. Feed with Na-B supplementation (5 and 10 g /kg diet) had a significant positive effect (P≤0.05) on body weight (BW), body weight gain (BWG), and feed intake (FI), as well as, serum globulin, triodothyronine hormone (T3), glutathione peroxidase (GPX) and decrease in mortality rate and malonidialdehyde (MDA) values. However, feed conversion ratio (FCR), total antibody responses against SRBCs, total protein, albumin, growth hormone (GH), cholesterol and calcium were insignificantly affected by these treatments, but they gave the highest net return and best economic efficiency (P≤0. 01) compared to their controls at 12 wks of age. Supplementation of 800 or 1200 μg CrPic /kg diet significantly increased BW, BWG and improved FCR, as well as, a titer of SRBCs, serum total protein, albumin, globulin, and GH concentrations. While, the mortality rate and serum cholesterol were significant (P≤0. 05) decreased. However, there were no significant differences among treatments in calcium, T3, MDA and GPX. Supplemented diets with CrPic gave the highest net return and best economic efficiency (P≤0. 01) compared to their controls. Moreover, BW, BWG, FI and FCR, mortality rate, serum globulin and calcium influenced by the interaction between dietary Na-B and CrPic. Whereas, SRBCs, total protein, albumin, GH, cholesterol, T3, MDA and GPX were not significantly influenced by their interaction. It is clear that, supplementing the chick’s diet with both 10 g Na-B and 1200 µg CrPic /kg diet alone or together is recommended for improving most of the growth performance, serum biochemical traits as well as improved immune responses and gave the highest net return and best economic efficiency during the growing period of Matrouh male chicks

The effect of dietary supplementation with chromium-enriched soya meal on lymphatic cells in caecal tonsil of laying hens

The study aimed to determine the effects of dietary supplementation with high dose of inorganic chromium from a new additive (soya meal enriched with Cr (III) by biosorption) on lymphatic cells in caecal tonsil of laying hens. The feeding experiment was conducted over 4 weeks on 60 laying hens from Hy-Line Brown line, aged 18 weeks. All birds were kept in a furnished Battery Cage System, in a room with a controlled climate conditions and light regimen of 13–15L:11–9D and were fed either a basal diet – control group (n=30) or the basal diet supplemented with chromium – Cr-treated group (n=30). The dietary treatments for Cr-treated group consisted of the basal diet supplemented with 87.7mgkg−1 chromium from a enriched soya meal (20.588±0.212mg of Cr(III) g−1). The samples of caecal tonsils were stained against chicken Bu-1, CD4, and CD8α antigens and the positive area fractions were counted. It was revealed that the population of CD4+ cells was significantly higher (p<0.001) by unchanged number of the Bu-1+ and CD8α+ cells in caecal tonsils of chromium-supplemented hens. The obtained results showed that the supplementation with high dose of chromium from a enriched soya meal stimulates the adaptive immune system in the caecal tonsil what may enhance the response against potentially dangerous antigens.

HEXAVALENT CHROMIUM REDUCTION POTENTIAL OF CHROMIUM RESISTANT TANNERY EFFLUENT BACTERIA AND THEIR CONSORTIA

Seventeen bacterial isolates from tannery effluent was tested for their ability to resist chromium (Cr) and reduce hexavalent chromium (Cr (VI)). Reduction study was carried out by individual isolates and also by their consortia. All the isolates could resist 25 mg L-1 chromium. Some isolate was found to resist &gt;90 mg L-1 chromium. It was evident that isolates those were more resistant to chromium were not necessarily reduce more chromium. Some of these isolates were identified by their 16S rRNA gene sequencing. In general tested isolates showed more reduction potential when Cr added at the starting point of culture propagation than Cr addition after passing exponential phase. Micrococcus sp. showed maximum Cr (VI) reduction ability in both condition. For construction of consortia bacteria were chosen according to their antagonistic and synergistic property. Those isolates exhibiting antagonistic activity to other isolates were excluded from consortia preparation. Two types of consortia were prepared by mixing well grown isolates in equal proportion. Type 1 consortia that was prepared by mixing six most chromium reducing bacteria showed lesser chromium reduction ability than type 2 consortia which was prepared by mixing isolates able to reduce &gt;1500 μg Cr(VI) g-1 dry cell biomass. It has been observed that, although isolate Micrococcus sp. individually reduce more chromium, consortia including this isolate did not performed well. Other combination of isolates including Micrococcus sp. might be able to reduce more chromium and could be studied further.

Thermal Decoating of Aerospace Aluminum Alloys for Aircraft Recycling

Recycling of aircraft aluminum alloys can be complex due to the presence of their corrosion protection coating that includes inorganic compounds containing Cr(VI). In this study, the characterization and thermal degradation behavior of the coating on aluminum substrates coming from an aircraft destined for recycling are presented. Elements such as Sr, Cr, Si, Ba, Ti, S, C, and O were found in three different layers by EDS elemental mapping corresponding to SrCrO4, Rutile-TiO2, SiO2, and BaSO4 with an overall particle size D 50 = 1.96 µm. The thermal degradation profile analyzed by TGA showed four different stages. The temperature of complete degradation at the fourth stage occurred at 753.15 K (480 °C) at lower heating rates. At higher heating rates and holding an isotherm at the same temperature, the residence time to fully decompose the aircraft coating has been estimated as 4.0 ± 0.2 minutes. The activation energy calculated by the Flynn–Wall–Ozawa and the modified Coats-Redfern methods for multiple fraction of decomposition showed a non-constant behavior indicating the complexity of the reaction. Finally, the concentration of Cr(VI) released to the environment during thermal decoating was obtained by UV–Vis spectroscopy. It was found that 2.6 ± 0.1 µg of Cr(VI)/mm2 of aluminum substrate could be released unless adequate particle controls are used.

Chromium (VI)-induced phytotoxicity in river catchment agriculture: evidence from physiological, biochemical and anatomical alterations in Cucumis sativus (L.) used as model species

ABSTRACT The present study investigates the impact of different Cr(VI) (50–200 µM) treatments on Cucumis sativus L. seedlings which is worldwide grown in river catchments. Chromium (VI) treatments showed significant (P < .05) reduction in growth, photosynthetic pigments, total protein content and PSII performance, which was in concurrence with a significant (P < .05) increase in the accumulation of Cr(VI) (up to 587 ± 18.19 µg Cr g−1 in roots), lipid peroxidation (MDA: up to 483%), H2O2 (up to 453%) and (up to 551%) compared to the control seedlings. Chlorophyll fluorescence parameters, such as F m, F v, F v/F m, F m/F 0 and F v/F 0, were declined while F 0 showed enhancements (P < .05). Energy flux parameters, such as Phi_E0, Psi_0, PIABS, declined; however, ABC/RC, ET0/RC, DI0/RC and TR0/RC increased significantly (P < .05) under Cr(VI) treatments as compared to control. In addition, the levels of qP were reduced while NPQ was appreciably enhanced under different Cr(VI) treatments. The histochemical observations of H2O2 and were in accordance with their total estimation. Furthermore, Cr(VI) also severely injured the anatomical structure of roots. This study suggests that a higher accumulation of Cr(VI) in cucumber seedlings warrants serious attention in the studied catchments of the Ganges river to avoid any food contamination and biomagnifications to higher trophic levels.

Chemical Modifications of Cassava Peel as Adsorbent Material for Metals Ions from Wastewater

Residues from the processing of cassava roots (Manihot esculentaCrantz), or cassava peels, are evaluated as chemically modified adsorbents with H2O2, H2SO4, and NaOH, in the removal of metal ions Cd(II), Pb(II), and Cr(III) from contaminated water. Modified adsorbents were chemically characterized for their chemical composition andpHPZC(point of zero charge), while adsorption tests determined the best conditions of pH, adsorbent mass, and contact time between adsorbent and adsorbate in the process of removal of the metal ions. Isotherms obtained from the preliminary results were linearized by Langmuir’s and Freudlich’s models. The thermodynamic parameters, such asΔH,ΔG, andΔS, were also evaluated. The modifying solutions proposed were effective in the modification of adsorbents and resulted in high capacity sorption materials. Equilibrium time between adsorbent and adsorbate for the solutions contaminated with metals is about 40 minutes. The Langmuir model adjusted to most results, indicating monolayers adsorption of Cd(II), Pb(II), and Cr(III). The values obtained for LangmuirQmshow a higher adsorption capacity caused by chemical modifications, with values such as 19.54 mg Cd(II) per g of M. NaOH, 42.46 mg of Pb(II) per g of M. NaOH, and 43.97 mg of Cr(III) per g of M H2O2. Results showed that modified cassava peels are excellent adsorbent, renewable, high availability, and low-cost materials and a feasible alternative in the removal of metals in industries.

EFFECT OF DIETARY CHROMIUM, SELENIUM AND VITAMIN C SUPPLEMENTATION TO THE DIET ON REPRODUCTIVE PERFORMANCE AND EGG QUALITY OF LAYING HENS DOKKI-4 UNDER EGYPTIAN SUMMER CONDITION

The study was performed to evaluate the effect of organic chromium (Cr), organic selenium (Se) or vitamin C (vit. C) alone or in combination on reproductive performance, and egg quality of Dokki-4 laying hens under hot summer conditions of Egypt. A total number of 240 hens plus 48 cocks from Dokki-4 strain at 30 weeks of age were randomly selected and distributed into eight groups with 3 replicates ( 10 hens + 1 cock) each. The remaining 24 cocks were also divided into 8 groups of 3 cocks each and housed separately for semen evaluation experiment. Treatments groups were fed a basal diet (control group) or the basal diet supplemented with either 400 μg Cr/kg diet (Cr group), 250 mg of L-ascorpic acid /kg diet (vit. C. group), 0.2 mg Se/kg diet (Se group), 400 μg Cr plus 250 mg of L-ascorpic acid/ kg diet (Cr + vit. C group), 400 μg Cr plus 0.2 mg Se/kg diet ( Cr + Se group), 2 mg Se plus 250 mg L-ascorbic acid/kg diet ( Se + vit. C. group) and 400 μ Cr plus 0.2 mg Se plus 250 mg ascorbic acid /Kg diet (Cr + Se + vit.C group). All groups were put under observation for 12 weeks. Results obtained can be summarized as follows: Supplementation of Cr, Se or vitamin C alone or in combinations significantly increased (P < 0.05) shell thickness, haugh units, albumin and shell to egg weight, sperm motility, ejaculate volume, sperm concentration, total sperm output, total motile sperm, live spermatozoa, semen quality factor and significantly decreased (P < 0.05) dead spermatozoa and seminal malondialdehyde (MDA) as compared with control group. The best result was obtained for layers fed diet containing the combinations of the three supplements (Cr, Se or vitamin C) as compared to other groups.In conclusion, combinations of Cr, Se and vitamin C improved the most reproductive traits and egg quality of Dokki-4 strain under Egyptian hot summer.

Heavy metal concentration in feathers of Little Egret (Egretta garzetta) nestlings in three coastal breeding colonies in Spain.

The colonial ardeid Little Egret (Egretta garzetta), which is is protected under the European Birds Directive (2009/147/EC), can be a reliable bioindicator of aquatic environmental pollution. Concentrations of the heavy metals Cd, Cr, Cu, Hg, Ni, Pb and Zn in nestling feathers were assessed for three different breeding colonies of Little Egret on the Spanish coast during 2013 (5 individuals in Urdaibai, 10 in Santoña and 26 in Odiel). There were no significant differences in mean tissue residues of Cd, Ni, Pb and Zn between the colonies; however, mean concentration of Hg in Odiel nestlings was approximately three times lower than that of the other colonies, while Cr and Cu were significantly higher. In general, Little Egret nestlings from the three study sites had low levels of most of the measured metals, and thus the breeding populations did not appear to be at risk from heavy metal pollution. Baseline metal concentration in feathers derived from this study and calculated as the 90th percentile values were: 0.02 μg Cd g(−1) dw, 0.42 μg Cr g(−1) dw, 1.63 μg Hg g(−1) dw, 0.40 μg Pb g(−1) dw and 122 μg Zn g(−1) dw. However, mean Cu residues attained relatively high levels (17.6–26.9 μg Cu g(−1) dw) compared with data reported elsewhere, which raises concern and indicates a need for further research.