Low Levels Of Cr Research Articles

Relationships between microvascular complications of diabetes mellitus and levels of macro and trace elements.

The aim of this study was to determine relationships between microvascular complications of type 2 diabetes mellitus (T2DM) and trace element levels measured by ICP-MS. One hundred eighteen patients with T2DM (age: 30-65 years) and 40 control subjects were included in the study. The T2DM patients were divided into three groups according to their types of microvascular complications. Patients in group 1 (N.=40) had no microvascular complications. Group 2 included 38 patients with only diabetic retinopathy. Group 3 included 40 patients with diabetic retinopathy and nephropathy. Trace elements, including chromium (Cr), copper (Cu), and zinc (Zn), were measured by inductively coupled plasma mass spectrophotometry (ICP-MS). Mg levels analyzed by ICP-MS were lower in patients with T2DM than in healthy subjects. Additionally, Mg level of 2.1 mg/dL or less was found to be predictive for risk of occurrence of T2DM with no microvascular complications. Cr levels were significantly lower in T2DM patients with diabetic retinopathy and diabetic nephropathy than in T2DM patients with no microvascular complications. Additionally, levels of Cr were much lower significantly in group 3 than in group 2. The predictive value of Cr levels (area under the curve [AUC]=0.734, P=0.007) for occurrence of diabetic retinopathy was 15.2 μg/L (sensitivity = 70%; specificity = 60.5%). This study showed an association between especially low Mg and Cr levels measured via ICP-MS and microvascular complications in patients with T2DM.

Comparing the Adsorption Performance of Multiwalled Carbon Nanotubes Oxidized by Varying Degrees for Removal of Low Levels of Copper, Nickel and Chromium(VI) from Aqueous Solutions

Functionalized multiwalled carbon nanotubes (MWCNTs) have drawn wide attention in recent years as novel materials for the removal of heavy metals from the aquatic media. This paper investigates the effect that the functionalization (oxidation) process duration time (3 h or 6 h) has on the ability of MWCNTs to treat water contaminated with low levels of Cu(II), Ni(II) and Cr(VI) (initial concentrations 0.5–5 mg L−1) and elucidates the adsorption mechanisms involved. Adsorbent characterization showed that the molar ratio of C and O in these materials was slightly lower for the oxMWCNT6h, due to the higher degree of oxidation, but the specific surface areas and mesopore volumes of these materials were very similar, suggesting that prolonging the functionalization duration had an insignificant effect on the physical characteristics of oxidized multiwalled carbon nanotubes (oxMWCNTs). Increasing the Ph of the solutions from Ph 2 to Ph 8 had a large positive impact on the removal of Cu(II) and Ni(II) by oxMWCNT, but reduced the adsorption of Cr(VI). However, the ionic strength of the solutions had far less pronounced effects. Coupled with the results of fitting the kinetics data to the Elowich and Weber–Morris models, we conclude that adsorption of Cu(II) and Ni(II) is largely driven by electrostatic interactions and surface complexation at the interface of the adsorbate/adsorbent system, whereas the slower adsorption of Cr(VI) on the oxMWCNTs investigated is controlled by an additional chemisorption step where Cr(VI) is reduced to Cr(III). Both oxMWCNT3h and oxMWCNT6h have high adsorption affinities for the heavy metals investigated, with adsorption capacities (expressed by the Freundlich coefficient KF) ranging from 1.24 to 13.2 (mg g−1)/(mg l−1)n, highlighting the great potential such adsorbents have in the removal of heavy metals from aqueous solutions.

MOF-Beads Containing Inorganic Nanoparticles for the Simultaneous Removal of Multiple Heavy Metals from Water.

Pollution of water with heavy metals is a global environmental problem whose impact is especially severe in developing countries. Among water-purification methods, adsorption of heavy metals has proven to be simple, versatile, and cost-effective. However, there is still a need to develop adsorbents with a capacity to remove multiple metal pollutants from the same water sample. Herein, we report the complementary adsorption capacities of metal-organic frameworks (here, UiO-66 and UiO-66-(SH)2) and inorganic nanoparticles (iNPs; here, cerium-oxide NPs) into composite materials. These adsorbents, which are spherical microbeads generated in one step by continuous-flow spray-drying, efficiently and simultaneously remove multiple heavy metals from water, including As(III and V), Cd(II), Cr(III and VI), Cu(II), Pb(II), and Hg(II). We further show that these microbeads can be used as a packing material in a prototype of a continuous-flow water treatment system, in which they retain their metal-removal capacities upon regeneration with a gentle acidic treatment. As proof-of-concept, we evaluated these adsorbents for purification of laboratory water samples prepared to independently recapitulate each of two strongly polluted rivers: the Bone (Indonesia) and Buringanga (Bangladesh) rivers. In both cases, our microbeads reduced the levels of all the metal contaminants to below the corresponding permissible limits established by the World Health Organization (WHO). Moreover, we demonstrated the capacity of these microbeads to lower levels of Cr(VI) in a water sample collected from the Sarno River (Italy). Finally, to create adsorbents that could be magnetically recovered following their use in water purification, we extended our spray-drying technique to simultaneously incorporate two types of iNPs (CeO2 and Fe3O4) into UiO-66-(SH)2, obtaining CeO2/Fe3O4@UiO-66-(SH)2 microbeads that adsorb heavy metals and are magnetically responsive.

Oxide scale on stainless steels and its effect on sticking during hot-rolling

The failure of oxide scales on ferritic stainless steels (STSs) has been known to cause an unexpected and severe sticking problem during the hot-rolling process. The oxide scale fragments formed during hot-rolling are stuck on the surfaces of the working roll, deteriorating the surfaces of both the roller and the rolled materials. In this study, we investigate the effects of the compositions and microstructures of thermally grown oxide scales on the degree of sticking during hot-rolling in three different kinds of commercial ferritic STSs and one austenitic STS. The STS samples are oxidized at around 1280 °C for 2 h, and the oxide scales formed on the STSs are identified by X-ray diffraction (XRD). Additionally, the cross-sectional microstructure and chemical compositions of the oxide scales on the STSs are examined by electron probe microanalysis (EPMA) and scanning electron microscopy (SEM), respectively. The oxide scales adjacent to the interfaces with the bulk STS are analyzed by high-resolution transmission electron microscopy (HR-TEM). The Gleeble test, which is a high-temperature (1250 °C) tensile test, is conducted to analyze the effects of the stress induced in the oxide scales during hot-rolling on the fracture of the scales. According to the microstructural analysis and mechanical test results, a brittle Cr2O3 layer, where cracks are easily formed and propagate through the scale thickness under the stress induced by hot-rolling, is formed along the interfaces of STSs with high Cr contents. This effect increases the probability of sticking failure in high-Cr STSs. In contrast, scales with a composite-like structure of Fe- and Cr-oxides are formed on the surface of STSs containing low and medium levels of Cr. According to the Gleeble test results, the composite-like oxide scales show higher mechanical resistance to tensile stress than the Cr2O3 layers in the high-Cr STSs. In addition, our microstructural analysis results reveal that FexNiy intermetallic compounds are observed as a form of a composite-like structure inside the oxide scales in the austenitic STS and that this structure also delays crack propagation through the oxide scales and reduces the degree of sticking.

Prevalence and predisposing factors of depressive symptoms in patients with stable coronary artery disease: a cross-sectional single-center study.

The incidence of depressive symptoms in patients with stable coronary artery disease (SCAD) has significantly increased. However, its pathogenesis and treatment mechanisms are still incompletely understood. In this study, 144 patients with SCAD were recruited. Depressive symptoms of patients with SCAD were evaluated using Zung Self-Rating Depression Scale during hospitalization, and the patients were categorized into two subgroups: the non-depressive and depressive groups (further divided into mild and moderate/severe depressive groups). The rate of moderate/severe depressive symptoms in patients with SCAD was 18.8%. The mean age of patients in the depressive and mild depressive groups was older than that of those in the non-depressive group, and patients in the moderate/severe depressive group had higher high-density lipoprotein (HDL) and lower creatinine (Cr) levels. Binary logistic regression analysis showed that lower low-density lipoprotein (LDL) levels were significantly associated with increased risks of mild depressive symptoms, whereas higher HDL and lower Cr levels were significantly associated with moderate/severe depressive symptoms, suggesting that patients with SCAD were prone to experience depressive symptoms, especially in the elderly. Abnormality in LDL, HDL, and Cr levels might contribute to the depressive symptoms.

Lixisenatide protects doxorubicin-induced renal fibrosis by activating wNF-κB/TNF-α and TGF-β/Smad pathways.

The aim of this study was to investigate whether Lixisenatide, NF-kB/TNF-α, and TGF-β/Smad pathways exert clear regulatory roles in doxorubicin-induced renal fibrosis in rats, and to explore the possible underlying mechanism. 30 rats were randomly assigned into the sham group, the Doxorubicin (DOX) group and the Lixisenatide group, 10 in each group. Eight weeks after the specific animal procedure, serum and kidney samples of rats were collected. The serum levels of Cr and BUN were detected using relative commercial kits. The activities of malondialdehyde (MDA), total antioxidant capacity (T-AOC), catalase (CAT), reduced glutathione (GSH), and superoxide dismutase (SOD) in kidney homogenate were accessed using commercial kits. Meanwhile, pathological lesions in kidney tissues were evaluated by HE staining, immune-histochemical staining and TUNEL assay, respectively. Also, the protein levels of relative genes in NF-kB/TNF-α, and TGF-β/Smad pathways in rat kidneys were determined by immune-histochemical staining and Western blot, respectively. Rats in the Lixisenatide group showed significantly lower levels of Cr and BUN. Activities of T-AOC, CAT, GSH, and SOD in the Lixisenatide group were significantly higher, whereas MDA activity was significantly lower than in the DOX group. Lixisenatide treatment remarkably alleviated DOX-induced pathological lesions and cell apoptosis in kidneys. Furthermore, the protein levels of relative genes in NF-kB/TNF-α and TGF-β/Smad pathways in rat kidneys were significantly downregulated in the Lixisenatide group when compared with the DOX group. Lixisenatide protects doxorubicin-induced renal fibrosis in rats by inhibiting NF-κB/TNF-α and TGF-β/Smad pathways.

Significance of Neutrophil/Lymphocyte Ratio in the Prognosis of Patients with Multiple Myeloma

To study the value of neutrophil/lymphocyte ratio (NLR) in the evaluation of prognosis of patients with multiple myeloma (MM). NLR was calculated on the basis of the blood routine examination results of 65 patients with primary MM (MM group) and 83 persons receiving physical examination as control group, and the difference in 2 group was compared; moreover according to the median as threshold, the patients were divided into low NLR group (NLR＜2.34) and high NLR group (NLR≥2.34); the differences of age, sex, serum calcium β2 (Ca), microglobulin (β2-MG), albumin (Alb), serum creatinine (Cr), hemoglobin (Hb), red blood cell distribution width (RDW) and lactate dehydrogenase (LDH) in 2 group were analyzed, and the survival rate was compared between the high and low-NLR group. the NLR of MM patients was statistically significantly higher than that of the control group (z=-2.415, P＜0.05). Compared with the low NLR group, the β2-MG and Cr levels of patients in the high NLR group seemed higher, but the difference was not statistically significant. The single-factor analysis showed that NLR, β2-MG and Alb levels were risk factors for the prognosis of MM patients, and the multi-factor analysis showed that NLR and Alb level were independent risk factors influencing the prognosis of MM patients. NLR elevation in patients with primary diagnosis of MM indicates a poor prognosis, which is an independent risk factor affecting the prognosis.

Detection of Hexavalent Chromium by Copper Sulfide Nanocomposites.

Chromium (Cr) is a vital environmental contaminant. In environmental matrixes, Cr presents dominantly in hexavalent chromium [Cr(VI)] and trivalent chromium [Cr(III)], which are two different inorganic states. Cr(VI) is a well-known human carcinogen, while Cr(III) is a naturally occurring micronutrient for the human body. Hence, speciation of Cr is crucial for ensuring environmental water and food safety. The distinction between each chromium species is almost impossible with commonly used methods like atomic spectrometric techniques, due to the low level of Cr and the high complexity of the matrix. Typically, a preconcentration step is required prior to determining and improving the selectivity and detection limit of the inspection instrument. For this process, nanocomposites, which are emerging high-quality adsorbents are used. However, preparation of previous nanocomposites suffered from a trivial synthesis process, had high reagent consumption, and was time-consuming. Therefore, we succinctly designed and fabricated the novel triadic silica gel-supported copper sulfide (CuS) nanocomposites for ultrasensitive detection of Cr(VI). CuS nanocomposites in a solid phase system were successfully applied to extract Cr(VI) in reference materials, such as food and water samples. Cr(VI) were detected by use of flame atomic absorption spectrometry (FAAS). By loading 30 mL of sample solution, a linear range of 0.5-300 μg L-1 with R = 0.998, a detection limit of 0.15 μg L-1, and an accuracy of 1.7% (20 μg L-1, n = 11) were obtained by this method. The detection limit and the precision of this procedure are superior to those reported in the literature with the same detection technique, indicating that CuS nanocomposites have a good potential for Cr(VI) detection which is essential for food safety and human health.

Proximate Analysis, Mineral Contents and Amino Acid Composition of Antrocaryon micraster Stem Bark

Proximate Analysis, Mineral Contents and Amino Acid Composition of Antrocaryon micraster Stem Bark Akinsola Abiodun Folasade, Omotayo Felix Olorunfemi Abstract In the present study, the proximate, mineral and amino acid composition of the stem bark of Antrocaryon micraster was determined. Results of the proximate analysis revealed the presence of 12.4 ± 0.0 % moisture; 9.01 ± 0.01 % ash; 13.8 ± 0.1 % crude protein; 1.20 ± 0.04 % fat and 51.9 ± 0.1 % carbohydrate. The mineral composition showed high level of K (889 ± 1.0 mg/100g), Ca (628 ± 3.0 mg/100g), P (104 ± 1.0 mg/100g) and low levels of Mn (6.71 ± 0.03 mg/100g), Zn (5.29 ± 0.10 mg/100g) and Cr (0.1 ± 0.0 mg/100g). The antinutrients studied revealed lower range of values when compared with most vegetables. Two acidic amino acids (glutamic and aspartic acid) were the highest concentrated amino acids (15.2 ± 0.0 and 10.0 ± 0.1 g/100g crude protein). The total amino acid was 81.6 g/100g crude protein, while the total essential and non-essential amino acids were 36.4 and 45.2 g/100g crude protein respectively. The predicted protein efficiency ratio (P-PER) of Antrocaryon micraster stem bark was 1.55 and the calculated isoelectric point (pI) was 4.67. Full Text: PDF DOI: 10.15640/jaes.v8n2a7

Evaluation of Heavy Metals in Fish, Water and Sediment of the New Calabar River

Aim: This study is aimed at determining the levels of some heavy metals in the water, sediment and fishes (Oreochromis niloticus, Periopthalmus koelreuteri, Micropogonias undulatus, Carassius auratus and Liza felcipinis) from new Calabar River located at Rumuolumeni Community in Obio/Akpor, Rivers State, Nigeria.
 Study Design: Fish, water and sediment samples were selected collected and analyzed for Pb, Cd, Fe, Cr, Mn, Cu and Zn.
 Methodology: The heavy metals concentration was determined by AAS. Health risk assessment of the samples was evaluated by Estimated daily intake (EDI), Toxic Hazard Quotient (THQ) and Carcinogenic Risk (CR).
 Results: P. koelreuteri had the highest mean concentration of Pb (3.82±0.11 mg/Kg); C. auratus samples had the highest mean concentration of Cd (3.82±0.06 mg/Kg); P. koelreuteri had the highest mean concentration of Fe and Cr (189.87±0.04 mg/Kg and 4.75±0.02 mg/Kg respectively); M. undulatus had the highest mean concentration of Cu (3.14±0.05 mg/Kg); O. niloticus had the highest mean concentration of Zn and Mn (38.48±0.02 mg/Kg and 17.25±0.02 mg/Kg respectively). Heavy metals concentration was significantly low (P=.05) when compared with the experimental groups. The sediment samples showed the following trends in concentration (mg/Kg): Fe>Mn>Zn>Cr>Cu>Pb>Cd. Water samples had very low levels of Pb, Cd, Cu and Cr (<0.001 mg/Kg) except Fe (8.68±0.01 mg/Kg), Zn (0.10±0.02 mg/Kg) and Mn 0.11±0.00 mg/Kg. Health risk assessment of the metals in the samples analyzed indicates that the EDI of all the metals were within permissible limits, THQ for all the metals analyzed (especially Pb and Cd) indicates a potential deleterious effect on humans who depend of these aquatic organisms for their protein sources while only Cr has CR values above permissible limits.
 Conclusion: Therefore the heavy metal levels of edible aquatic species within this area should be continuously monitored to ensure the safety of consumers of such organisms.

On the Relationship between the Chromium Concentration, the Z‐Phase Formation and the Creep Strength of Ferritic‐Martensitic Steels

In this study, the long term creep strength behavior of commercial heat resistant martensitic/ferritic steels with Cr levels ranging from 1 to 15 wt% is analyzed by linking their computed equilibrium compositions to their creep properties. At lower Cr levels, the calculated strength due to precipitation hardening agrees well with the experimental results. At high chromium levels and longer exposure times, an accelerated strength loss due to the formation of Z‐phase precipitates has been reported. The accelerated strength loss is computationally analyzed and a correlation between accelerated strength loss and Z‐phase formation is confirmed. A study is made to explore the option of adjusting the chemical composition of existing high‐chromium steels to reduce the driving force for Z‐phase formation. However, no proper composition ranges are found which combine a high Cr concentration with a significantly lower driving force for Z‐phase formation.

Application of a surfactant-assisted dispersive liquid-liquid microextraction method along with central composite design for micro-volume based spectrophotometric determination of low level of Cr(VI) ions in aquatic samples

A fast, simple, low cost surfactant-assisted dispersive liquid-liquid microextraction method along with central composite design for the determination of low level of Cr(VI) ions in several aquatic samples has been developed. Initially, Cr(VI) ions present in the aqueous sample were readily reacted with 1,5‑diphenylcarbazide (DPC) in acidic medium through complexation. Sodium dodecyl sulfate (SDS), as an anionic surfactant, was then employed as an ion-pair agent to convert the cationic complex into the neutral one. Following on, the whole aqueous phase underwent a dispersive liquid-liquid microextraction (DLLME) leading to the transfer of the neutral complex into the fine droplet of organic extraction phase. A micro-volume spectrophotometer was used to determine Cr(VI) concentrations. Under the optimized conditions predicted by the statistical design, the limit of quantification (LOQ) obtained was reported to be 5.0 μg/L, and the calibration curve was linear over the concentration range of 5–100 μg/L. Finally, the method was successfully implemented for the determination of low levels of Cr(VI) ions in various real aquatic samples and the accuracies fell within the range of 83–102%, while the precision varied in the span of 1.7–5.2%.

A comprehensive study including monitoring, assessment of health effects and development of a remediation method for chromium pollution

Chromium (Cr) pollution caused by wastewater from tanneries is a worldwide environmental problem. To develop a countermeasure, we performed a comprehensive study using Hazaribagh, the tannery area in Dhaka City, Bangladesh, as a model. Our environmental monitoring indicated that the soluble form of Cr, but not barium or arsenic, in Buriganga River is derived from Hazaribagh. Our chemical analysis next showed that Cr, the primary pollutant in canal water at Hazaribagh, consisted of ≤0.7 μM hexavalent Cr [Cr(VI)] and ≤1705 μM trivalent Cr [Cr(III)]. Our biological study then showed that coexposure to Cr(VI) and Cr(III) at possible ratios in canal water at Hazaribagh synergistically promotes transforming activity of human non-tumorigenic HaCaT keratinocytes with activated MEK/ERK and AKT. Our environmental engineering study finally indicated that a magnesium and iron-based hydrotalcite-like compound (MF-HT), our original depurative, can maximally adsorb 9.0 mg/g Cr(VI) and 1041 mg/g Cr(III). Our results suggested the importance of removal of Cr(III) as well as Cr(VI) by showing that Cr(III), which is generally recognized as a chemical with low toxicity, synergistically promoted carcinogenicity of a low level of Cr(VI). Therefore, we propose the use of our original high-efficient and low-cost depurative as a countermeasure to address the worldwide problem of environmental Cr pollution.

Nanoencapsulation of hexavalent chromium with nanoscale zero-valent iron: High resolution chemical mapping of the passivation layer

Solid phase reactions of Cr(VI) with Fe(0) were investigated with spherical-aberration-corrected scanning transmission electron microscopy (Cs-STEM) integrated with X-ray energy-dispersive spectroscopy (XEDS). Near-atomic resolution elemental mappings of Cr(VI)–Fe(0) reactions were acquired. Experimental results show that rate and extent of Cr(VI) encapsulation are strongly dependent on the initial concentration of Cr(VI) in solution. Low Cr loading in nZVI (<1.0wt%) promotes the electrochemical oxidation and continuous corrosion of nZVI while high Cr loading (>1.0wt%) can quickly shut down the Cr uptake. With the progress of iron oxidation and dissolution, elements of Cr and O counter-diffuse into the nanoparticles and accumulate in the core region at low levels of Cr(VI) (e.g., <10mg/L). Whereas the reacted nZVI is quickly coated with a newly-formed layer of 2–4nm in the presence of concentrated Cr(VI) (e.g., >100mg/L). The passivation structure is stable over a wide range of pH unless pH is low enough to dissolve the passivation layer. X-ray photoelectron spectroscopy (XPS) depth profiling reconfirms that the composition of the newly-formed surface layer consists of Fe(III)–Cr(III) (oxy)hydroxides with Cr(VI) adsorbed on the outside surface. The insoluble and insulating Fe(III)–Cr(III) (oxy)hydroxide layer can completely cover the nZVI surface above the critical Cr loading and shield the electron transfer. Thus, the fast passivation of nZVI in high Cr(VI) solution is detrimental to the performance of nZVI for Cr(VI) treatment and remediation.

Phyto-management of chromium contaminated soils through sunflower under exogenously applied 5-aminolevulinic acid

Soil contamination with heavy metals is threatening the food security around the globe. Chromium (Cr) contamination results in poor quality and reduction in yield of crops. The present research was performed to figure out the Cr toxicity in sunflower and the ameliorative role of 5-aminolevulinic acid (ALA) as a plant growth regulator. The sunflower (FH-614) was grown under increasing concentration of Cr (0, 5, 10 and 20mgkg−1) alone and/or in combination with 5-ALA (0, 10 and 20mgL−1). Results showed that Cr suppressed the overall growth, biomass, gas exchange attributes and chlorophyll content of sunflower plants. Moreover, lower levels of Cr (5 and 10mgkg−1) increased the production of reactive oxygen species (ROS) and electrolyte leakage (EL) along with the activities of antioxidant enzymes i.e., superoxide dismutase (SOD), guaiacole peroxidase (POD), ascorbate (APX), catalase (CAT). But at higher concentration of Cr (20mgkg−1), the activities of these enzymes presented a declining trend. However, the addition of 5-ALA significantly alleviated the Cr-induced toxicity in sunflower plant and enhanced the plant growth and biomass parameters along with increased chlorophyll content, gas exchange attributes, soluble proteins and soil plant analysis development (SPAD) values by scavenging the ROS and lowering down the EL. The 5-ALA also enhanced the activities of antioxidant enzymes at all levels of Cr. The increase in Cr concentration in all plant parts such as leaf, root and stem was directly proportional to the Cr concentration in soil. The application of 5-ALA further enhanced the uptake of Cr and its concentration in the plants. To understand this variation in response of plants to 5-ALA, detailed studies are required on plant biochemistry and genetic modifications.

新疆焉耆盆地辣椒地土壤重金属污染及生态风险预警

PDF HTML阅读 XML下载 导出引用 引用提醒 新疆焉耆盆地辣椒地土壤重金属污染及生态风险预警 DOI: 10.5846/stxb201611302449 作者: 作者单位: 作者简介: 通讯作者: 中图分类号: 基金项目: 国家自然科学基金项目（41561073）；新疆杰出青年科技人才培养项目（qn2015jq003） Soil heavy metal pollution and ecological risk warning assessment of pepper field in Yanqi Basin, Xinjiang Author: Affiliation: Fund Project: 摘要 | 图/表 | 访问统计 | 参考文献 | 相似文献 | 引证文献 | 资源附件 | 文章评论 摘要:从新疆加工辣椒主产地（焉耆盆地）采集105个辣椒地典型土壤样品，测定其中As、Cd、Cr、Cu、Mn、Ni、Pb和Zn等8种重金属元素的含量。采用污染负荷指数（Pollution load index，PLI）、潜在生态风险指数（Potential ecological risk index，RI）和生态风险预警指数（Ecological risk warning index，IER）对辣椒地土壤重金属污染及生态风险进行评价。结果表明：（1）焉耆盆地辣椒地土壤Cd、Cr、Ni、Pb和Zn含量的平均值分别超出新疆灌耕土背景值的1.65、1.40、1.32、3.21、6.42倍。辣椒地土壤Pb和Zn呈现重度污染，Cd、Cr和Ni轻度污染，As、Mn和Cu无污染。（2）土壤PLI平均值为1.40，呈现轻度污染。各重金属元素单项生态风险指数从大到小依次为：Cd、Ni、As、Cu、Pb、Cr、Zn。土壤RI平均值为18.40，属于轻微生态风险态势，IER平均值为-4.78，属于无警态势；博湖县辣椒地污染水平、潜在生态风险程度与生态风险预警等级最高，焉耆县污染水平、潜在生态风险程度与生态风险预警等级最低。（3）辣椒地土壤As、Cd、Pb与Zn主要受到人类活动的影响，Cr、Cu、Mn和Ni主要受到土壤地球化学作用的控制。Cd是焉耆盆地辣椒地生态风险等级最高的重金属元素，研究区农业生产过程中要防范Cd的污染风险。 Abstract:Heavy metals have long been recognized as pollutants that are potentially harmful to human health. In recent decades, research on heavy metals in soil environments has become a hotspot in environmental research. Under normal conditions, heavy metal concentrations in soils are several orders of magnitude higher than that in the background value of soils. Thus, the concentrations and potential ecological risks of heavy metals in farmland soils are important reference indicators for evaluating farmland soil environmental quality. Human activities are known to result in heavy metal pollution of farmland soils. Recent research in this field in China has focused on the sources, distribution, pollution, and ecological risk of heavy metals in farmland soils in the eastern or central parts. However, there has been limited research on soil contamination of farmland, particularly pepper fields, in the arid regions of northwest China. Therefore, we collected a total of 105 soil samples from pepper field in the main pepper production area (Yanqi Basin) in Xinjiang, China, and determined the content of eight heavy metals (As, Cd, Cr, Cu, Mn, Ni, Pb, and Zn) by standard methods. The heavy metal pollution of pepper field soils was analyzed based on pollution load index (PLI), potential ecological risk index (RI), and ecological risk warning index (IER). The results indicated that the average content of Cd, Cr, Ni, Pb, and Zn exceeded 1.65, 1.40, 1.32, 3.21, and 6.42 times, respectively, that of the background values for irrigation soil in Xinjiang. High levels of Pb, and Zn pollution, low levels of Cd, Cr and Ni pollution, and no As, Mn, or Cu pollution were detected in pepper field soils. The average value of PLI was 1.40, which showed a light pollution level; the average RI for each heavy metal in decreasing order was as follows:Cd, Ni, As, Cu, Pb, Cr, and Zn. The average value of RI of soil was 18.40, which indicated light ecological risk. The average value of IER of soil was -4.78, which indicated a no warning situation. The pollution level, potential ecological risk, and ecological risk warming of Bahrash county were the highest, whereas those of Hejing county were the lowest in Yanqi Basin. As, Cd, Pb, and Zn pollution in pepper field soil were mainly affected by the human activities, and Cr, Cu, Mn, and Ni pollution were mainly affected by the geochemical background of soils. Cd was the main pollutant of farmland soil with strong influence on the PLI, RI, and IER. The pollution risk of Cd should be a major concern during the process of agricultural production in Yanqi Basin. 参考文献 相似文献 引证文献

Trace elements profiles of maternal blood, umbilical cord blood, and placenta in Beijing, China

Aim Profiles of heavy metals such as chromium (Cr), manganese (Mn), arsenic (As), lead (Pb), and cadmium (Cd), and micronutrients such as ferrum (Fe), copper (Cu), zinc (Zn), and selenium (Se) in maternal and umbilical cord blood clots were investigated for assessing placenta function in the transport of micronutrients or heavy metal pollutants. Methods Correlations between contents of elements in the two tissues were also analyzed. Results Significantly lower levels of Cr, Pb, and Cd in umbilical cord blood clots than in maternal blood clots, and negative relationship between lead levels in maternal and umbilical cord blood (r = −.334, p = .016). Concentration of Mn in cord blood was significantly higher than that in maternal blood clots and positively related to the maternal level. The data also show that the placenta may work most strongly as a barrier against Cd and protects fetus from its harmful effect, while plays almost no role in preventing the transportation of As, Mn, and Pb. Conclusions In conclusion, pregnant women should avoid exposure to environment polluted with heavy metals, particularly with As, Mn, and Pb.

Structural impact of chromium incorporation in as-grown and flash-lamp-annealed sputter deposited titanium oxide films

We address the impact of chromium (Cr) incorporation (<15 at.%) in the structure of titanium dioxide (TiO2:Cr) films for as-grown and after flash-lamp-annealing (FLA) states. Samples were produced by DC magnetron sputtering on either unheated or heated (400 °C) substrates. Complementary medium- and local-order information was extracted by X-ray diffraction and absorption near-edge structure, respectively. TiO2:Cr grown on unheated substrates are amorphous with the major contribution from Cr3+ and progressive formation of Cr6+ with Cr. On heated substrates, anatase phase is dominant for low Cr levels (≤7 at.%) and the structure evolves with Cr towards a disordered mixed-oxide with rutile structure. By tuning the FLA energy density, customized (single or mixed) phase formation is achieved from (initially amorphous) Cr-free TiO2. For amorphous TiO2:Cr with low Cr (≤7 at.%), FLA induces a short-range rutile structure but structural ordering is not observed at higher Cr levels. Nonetheless, FLA annihilates Cr6+ sites and promotes Cr4+, which is associated to the mixed-oxide rutile. FLA also improves the pristine structure of anatase TiO2:Cr grown on heated substrates. These results provide relevant information about the atomic structure of mixed oxides and the use of FLA for the synthesis of band-gap engineered TiO2-based materials.

Relationship between heavy metal accumulation and morphometric parameters in European hare (Lepus europaeus) inhabiting various types of landscapes in southern Poland

To evaluate the influence of hazardous substances in the environment, studies of pollutant accumulation in wild living animals are needed. Studies dealing with heavy metal contamination in mammals usually focus on a single organ. We investigated accumulation of heavy metals as well as iron in European hare (Lepus europaeus) living in southern Poland, Małopolska Province. Hares were captured during the hunting season. We tested metal accumulation in 14 organs and tissues using 35 individuals with known body weight and sex inhabiting agricultural, industrial and other types of landscapes. To obtain deeper insight into contamination patterns, we used accumulation data from the liver since it is the most frequently investigated organ and prone to pollution accumulation. Based on the data obtained for the liver, we tested the impact of metal pollution on hare morphology, including body length and several skull cranimetric parameters.Metals content differed between organs. Moreover, individuals from industrial areas had higher Cd content in their body. We distinguished two groups of elements: the first group, Cd, Fe and Zn, revealed the highest toxic effect in the liver and kidneys; the second group, Cr, Ni, and Pb, accumulated primarily in the brain. Hares inhabiting industrial areas had higher concentration of Cd and Pb, and lower levels of Cr and Fe in their liver in comparison with those from agricultural and forest habitats. Heavy metals had an effect on body length that was negatively associated with Cr levels. Skull diastema length was associated positively with accumulation of Cd and Pb. We showed that hare organs and tissues could be used as bioindicators of environmental pollution by heavy metals.

LOW SERUM CHROMIUM IS RARE IN PATIENTS THAT UNDERWENT ENDOSCOPIC GASTROSTOMY FOR LONG TERM ENTERAL FEEDING.

Patients that underwent Percutaneous Endoscopic Gastrostomy (PEG) present with protein-energy malnutrition. Trace elements are required in small quantities and Chromium (Cr) displays a major role in the metabolism. This study aims to evaluate Cr levels and its relationship with serum proteins, BMI and underlying diseases during the first 3 months of PEG feeding. Prospective observational study during 3-months, when PEG was performed (T0), after 4 (T1), and 12 weeks (T3). Initial evaluation included: age, gender, underlying disease, NRS-2002, BMI, serum albumin, transferrin and Cr concentration. At T1 and T3 a blood sample was collected for Cr, albumin and transferrin. A Graphite Furnace Atomic Absorption Spectroscopy was used to assess Cr. According with the underlying disease, patients were divided into two groups: head and neck cancer (HNC) and neurological dysphagia (ND). All patients were fed with homemade meals. A one hundred and twenty-nine patients (80 males), 26-95 years old were studied: HNC-52; ND-77. The observed data included low mean values of BMI from 71 patients; low Cr-8, low albumin-70, low transferrin-85 and 57 with both proteins low. Albumin was associated with survival time ( P =0.024) and there was a significant correlation between albumin and Cr (r=0.217, P =0.012). A good evolution of Cr and proteins values was observed, with no low Cr levels at T3. Low serum Cr is rare in PEG-patients, with no relationship to other studied parameters. For the minority of patients displaying low Cr before gastrostomy, homemade PEG meals seem to be effective.