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[Remediation of chromium-polluted soil using municipal solid waste compost].

A study on the feasibiltiy of remediation of Cr-polluted soil using municipal solid waste(MSW) compost was carried out. The result showed that organic matter(O.M.), Eh, pH and < 0.01 mm of clay would influence the bioavailability of chromium in the soil, and O. M. and Eh were the principal influencing factors in the dryfield and inundating soil, up to 73.40% and 55.5% of the contribution rate affecting the bioavailability of chromium, respectively. The osmosis of the soil was improved when compost was applied, but the quantity of movable chromium was reduced because chromium in soil was deoxidized and adsorbed. MSW compost could reduce the absorption of chromium by the tested plant. The yield of the plant grown in the dry soil was increased by 35.9% and the content of Cr in the plant was decreased by 48.9%. The effect was more notable in the inundating soil: 86.3% of the yield increased and 23.8% of the Cr content decreased. However, MSW compost could not increase the risk of other heavy metal pollution.

Chromium↗

Epidemiological correlation between chromium content in gallstones and cholesterol in blood.

The authors measured the chromium in gallstones and bile from patients in three areas (Kawasaki (a city adjacent to Tokyo) in Japan, Chiang Mai and Bangkok in Thailand) by means of neutron activation analysis. The chromium in three types of gallstones (cholesterol, pigment, and rare stones) and bile from patients living in Bangkok were evidently larger than those from patients living in Kawasaki and Chiang Mai. The high chromium intake by Bangkok patients continued from the start of gallstone formation until the time the stones were removed. The total-cholesterol, triglyceride, and hemoglobin A(1C) levels in the blood from Bangkok residents with high chromium intake over a long period were clearly lower than those of Japanese and Chiang Mai residents. The authors showed that the high dietary intake of chromium over a long period may play a role in the lowering of total-cholesterol, triglyceride, and hemoglobin A(1C) in blood.

Adult↗

[Effect of chromium gluconate on body weight, serum leptin and insulin in rats].

In order to observe the effect of chromium on rat body weight, serum leptin and insulin, eight groups of rats were randomly fed diets (basal diet or high-fat diet) with different levels of chromium gluconate [proximally Cr(III) 1,2 and 3 mg/kg BW]. All rats were weighted once a week. By the end of the 8th week, all rats were decapitalized and the levels of serum leptin and insulin were tested by RIA method. The ratio of liver, spleen, kidney and testickle to body weight were calculated. The average body weight and the levels of leptin and insulin of high-fat-diet groups were significantly higher than those of the basal-diet group (P < 0.05), but the insulin and leptin of groups with chromium were significantly lower than their corresponding control groups without chromium(P < 0.05). It was concluded that chromium could cause weight loss slightly and reduce the levels of insulin and leptin.

Animals↗

Preliminary evaluation of salivary pellicle on nickel-chromium alloy in vivo.

OBJECTIVE: The composition of the salivary interface (pellicle) between dental restorations and oral mucosa may be critical to the biocompatibility of the restoration. The purpose of this study was to examine the molecular composition of the salivary pellicle on nickel-chromium alloy in vivo. METHOD AND MATERIALS: The molecular components of nickel-chromium pellicle was examined with sodium dodecyl sulfate-polyacrylamide gel electrophoresis and Western blot analyses. RESULTS: Only limited numbers of salivary proteins were found to participate in the formation of nickel-chromium pellicle in vivo. Salivary amylase and secretory immunoglobulin A were among the proteins identified in the pellicle. CONCLUSION: In vivo, nickel-chromium pellicle consists of selectively adsorbed salivary proteins. Because both salivary amylase and secretory immunoglobulin A are antimicrobial proteins, it is possible that they play a role in modulating the microbial flora on the nickel-chromium prosthesis.

Adsorption↗

Laboratory scale studies on removal of chromium from industrial wastes.

Chromium being one of the major toxic pollutants is discharged from electroplating and chrome tanning processes and is also found in the effluents of dyes, paint pigments, manufacturing units etc. Chromium exists in aqueous systems in both trivalent (Cr(3+)) and hexavalent (Cr(6+)) forms. The hexavalent form is carcinogenic and toxic to aquatic life, whereas Cr(3+) is however comparatively less toxic. This study was undertaken to investigate the total chromium removal from industrial effluents by chemical means in order to achieve the Pakistan NEQS level of 1 mg/L by the methods of reduction and precipitation. The study was conducted in four phases. In phase I, the optimum pH and cost effective reducing agent among the four popular commercial chemicals was selected. As a result, pH of 2 was found to be most suitable and sodium meta bisulfate was found to be the most cost effective reducing agent respectively. Phase II showed that lower dose of sodium meta bisulfate was sufficient to obtain 100% efficiency in reducing Cr(6+) to Cr(3+), and it was noted that reaction time had no significance in the whole process. A design curve for reduction process was established which can act as a tool for treatment of industrial effluents. Phase III studies indicated the best pH was 8.5 for precipitation of Cr(3+) to chromium hydroxide by using lime. An efficiency of 100% was achievable and a settling time of 30 minutes produced clear effluent. Finally in Phase IV actual waste samples from chrome tanning and electroplating industries, when precipitated at pH of 12 gave 100% efficiency at a settling time of 30 minutes and confined that chemical means of reduction and precipitation is a feasible and viable solution for treating chromium wastes from industries.

Carcinogens, Environmental↗

Chromium removal and reduction in COD of tannery effluents.

Tannery effluents are highly polluting and contain chromium and high COD and BOD. Alkalotolerant/alkalophilic actinomycetes NCIM 5080 and NCIM 5109 have been shown earlier to tolerate and accumulate chromium during growth also produce alkaline protease in presence of chromium ions. These properties of the isolates are suitable for treatment of tannery effluents which are alkaline and contain chromium and proteinaceous matter. Both the actinomycetes are able to grow in undiluted tannery effluents and remove chromium almost completely and reduce the COD by 70-80% during growth as well as by pregrown biomass.

Actinobacteria↗

Health implication among occupational exposed workers in a chromium alloy factory, Thailand.

This study was conducted to assess the occupational exposure and its health impact on the chromium alloy workers. Environmental and biological monitoring, noise and audiometry measurements were done to evaluate the exposure levels in the factory. A total of 112 non-smoking workers were monitored from July 2001 to August 2002. The results showed that most of the chromium and lead exposures in the factory were below the ACGIH-TWA of 50 microg/m3 for chromium(VI) and OSHA-PEL of 50 microg/m3 for lead. The highest chromium (7.25 +/- 0.16 microg/m3) and lead (14.50 +/- 0.29 microg/m3) concentrations were measured in the vibro room. The results indicated that elevated concentrations of chromium and lead were found in both blood and urine samples especially in those areas which were characterized by poor ventilation. The metal contents in blood and urine samples were significantly correlated with airborne metal concentrations in the factory. The result demonstrated that blood and urinary levels among workers were associated with increasing age and duration of exposure. The background noise level of the factory ranged from 67.6 to 89.2 dBA and was frequently higher than the threshold limit value for noise (90 dBA). According to the audiometric test, the exposed workers showed signs of noise-induced hearing loss. Noise at work continued to be an important factor to hearing loss among exposed workers. In our statistical analysis, a significant hearing loss was established on age effect and year of exposure among the workforce.

Age Factors↗

[On the suitability of migration inhibition techniques in the in-vitro-diagnostics of chromium allergy (author's transl)].

1. Under the conditions of cell culture potassium dichromate is reduced to trivalent chromium (diphenylcarbacid/fotometry). Trivalent chromium reacts with proteins more strongly than the hexavalent chromium (gelchromatography/atom absorption spectrophotometry) and presumably represents the actual hapten. 2. Because of this in-vitro-conjugation chromium salts are suitable in their unconjugated form for applying in migration inhibition tests (capillary/Clausen technique). 3. In migration inhibition tests potassium dichromate showed a better antigenicity than chromium chloride. The capillary method was more sensitive than the Clausen technique when using the same test concentration. 4. Correlations between the degree of the patch test and the value of the migration inhibition did not exist.

Allergens↗

Growth of Brassica juncea under chromium stress: influence of siderophores and indole 3 acetic acid producing rhizosphere bacteria.

Plant growth promoting rhizobacterial (PGPR) strains A3 and S32 have been shown to promote the growth of Brassica juncea under chromium stress which has been related to the microbial production of siderophores and indole 3 acetic acid (IAA). The aim of the present study is to evaluate the importance of siderophores and IAA producing PGPR on the growth of Brassica juncea under chromium stress. The production of IAA and siderophores were observed in the strains A3 and S32, respectively. Both PGPR strains promote the growth of Brassica juncea under chromium stress. The maximum growth was observed in plants inoculated with siderophores producing strain 32. Both the bacterial inoculum did not influence the uptake of chromium by plants. The present observation showed that PGPR isolates A3 and S32 are capable of protecting the plants against the inhibitory effects of chromium by producing the siderophores and IAA.

Bacillus↗

[Protective effect of zinc in chromium poisoning in rats].

The effect of a toxic trivalent chromium dose on histopathological changes in rat organs was investigated. To evaluate a protective effect of zinc, rats were treated with ZnCl2 two hours before chromium administration. The protective zinc action was best observed in respect to morphological changes in the organs of chromium poisoned rats, particularly in the liver. The lack of areas of focal necrosis on the liver capsule in the protected group of rats was the most evident macroscopic findings. The histopathological changes observed were in accordance with the results of own previous investigation of the changes in lactate dehydrogenase activity in rat organs induced by chromium and zinc. The mechanisms of the zinc protective effect against chromium poisoning are discussed.

Animals↗

Effect of chromium on growth of Pseudomonas aeruginosa.

Tolerance level to trivalent chromium-Cr(salen)(H2O)2+ and hexavalent chromium-K2Cr2O7 was assessed in P. aeruginosa isolated from tannery effluent soil. It could tolerate 80 and 100 ppm in liquid cultures and up to 100 and 200 ppm in plate count agar in the presence of trivalent and hexavalent chromium respectively. Unadapted cells took a longer time to grow than adapted cells in the presence of K2Cr2O7. Chromium influenced the cellular contents, morphology and respiration of P. aeruginosa. The chosen trivalent salt of chromium was more toxic than the hexavalent one.

Chromium↗

Survey of total and bioavailable chromium in grain and cereal products by atomic absorption spectrophotometry.

The chromium content of samples of cereals, legumes, oil seeds, and alimentary pastes (in the latter, bioavailable chromium as well) was determined by atomic absorption spectrophotometry. The chromium content in whole cereals differs substantially and is mostly concentrated in pericarps. Variations occur not only among different types of cereals, but also among cereals of the same type, depending on the areas of origin. Concentration varies substantially even in samples of legumes and oil seeds. The content of bioavailable chromium (ethanol-extractable) is, in most cases, more than 50% of the total chromium amount. This makes these products particularly interesting as dietary supplements.

Amino Acids↗

The effect of prolonged treatment with differing doses of chromium on glucose homeostasis in rabbits.

The effect of prolonged treatment with chromium on glucose homeostasis was assessed in rabbits. Thirty-one male rabbits were divided into 6 groups. All were fed for 30 days with a standard ad libitum diet. Twenty-seven rabbits were injected daily during a further 120 days with different doses of potassium chromate (3-20 micrograms) while 4 rabbits served as controls. No significant rise in serum glucose levels was observed, insulin levels were the same in the different groups, and glycosylated hemoglobin concentration also did not change after the administration of chromium. Serum chromium levels increased proportionally to the dose injected to an almost a 14 fold increase in the 20 micrograms chromium treated group. Although others have shown that chromium may have a hyperglycemic effect with inhibition of insulin secretion, we have not been able to confirm this finding.

Animals↗

Concentrations of chromium, cesium, and tin in cerebrospinal fluid of patients with brain neoplasms, leukemia or other noncerebral malignancies, and neurological diseases.

We measured the concentrations of chromium, cesium, and tin in the cerebrospinal fluid (CSF) of 29 patients with brain tumors [21 benign (BBT) and eight malignant (MBT)], 28 leukemic patients, 14 patients with lymphoma or noncerebral solid tumors (NLCT), and 32 control patients (15 with neurological disorders and 17 with noneurological conditions) by use of flameless atomic absorption spectrophotometry. We detected chromium in 94% of the patients, tin in 79%, and cesium in 50%. The mean (and SEM) concentrations (micrograms/L) of these metals in the control group were 4.7 (1.1) for chromium, 3.8 (1.6) for cesium, and 6.4 (1) for tin. We observed significant differences (P less than 0.05) in the concentration of chromium in CSF between the MBT group and all other tumor groups; the ratios for the mean CSF concentration of chromium in patients with BBT, leukemia, or NLCT to that in patients with MBT were 2.6, 2.1, or 4.4, respectively. We saw no significant differences in the concentrations of cesium or tin among the various groups investigated.

Adolescent↗

Effects of arsenic, selenium, and chromium on the fidelity of DNA synthesis.

The effect of three environmentally important metals, arsenic, selenium, and chromium, on the accuracy of DNA synthesis in vitro has been analyzed. The addition of arsenic to fidelity assays did not significantly alter accuracy. Selenium did not alter fidelity under normal conditions of magnesium activation, nor did it affect the mutagenicity of manganese. Chromium in the form of Cr(III) as well as Cr(VI) diminished the fidelity by which Escherichia coli DNA polymerase I copies polynucleotide templates. Nearest-neighbor analysis of the product synthesized in the presence of chromium indicates that the misincorporated in the presence of chromium indicates that the misincorporated bases are present as single-base substitutions. Chromium was also mutagenic using the recently developed phi chi 174 assay, which measures the fidelity of DNA synthesis with a natural DNA template.

Arsenic↗

[Baker's eczema through chromium compound in flour (author's transl)].

In several former papers on baker's eczema authors happened to hint at hypersensitivity to chromium in bakers suffering from eczema. To our knowledge however the question, if there is any connection between chromium-hypersensitivity and a baker's occupation, has not been investigated later on. In a baker with eczema of the hands relapses occurred obviously as a consequence of exclusive contact to flour, only hypersensitivity to chromium was revealed. Thus 4 sorts of flour used in GDR were analysed. Chromium content ranged between 0.01 and 0.09 mg%. It may be concluded, that even those comparatively low chromium levels are capable of giving rise to eczema.

Chromium↗

[Relation between environmental concentration, urinary elimination and body burden of chromium in occupationally exposed workers].

Biological and environmental monitoring of chromium exposure was carried out on 20 welders working with special electrodes in the manufacture of tank-cars. The workers were divided in groups, according to the different degree of chromium accumulation, which was determined by renal clearance of diffusible chromium. A closed linear relationship between TWA concentration of hydrosoluble chromium in air and urinary excretion of the metal at the end of exposure was observed. The parameters of regression lines in welders with more (clearance 10 ml/min) or less (clearance 5 ml/min) accumulation of chromium suggest that the renal burden influences not only the basal excretion, but also the excretion at the end of exposure. We underline the difficulty in the determination of correct biological limits if we take them from TLV in air. We must at least consider the degree of accumulation in exposed workers too.

Air Pollutants↗

Simulated knee wear with cobalt chromium and oxidized zirconium knee femoral components.

A knee simulator that mimics the plowing/rolling wear mechanisms of the knee was used to compare wear properties of cobalt chromium and oxidized zirconium femoral components. The simulator flexes and extends the knee so that the femoral components travels from 0 degrees to 30 degrees while applying axial loads from 130 to 1300 lb. Three oxidized zirconium and 3 cobalt chromium femoral components were tested with 10-mm tibial polyethylene components. The oxidized zirconium femoral components caused significantly less ultra high molecular weight polyethylene wear than cobalt chromium femoral components. Tibial inserts that were articulated against the cobalt chromium components had evidence of scratching, burnishing, and delamination, but none of the surfaces that were articulated against oxidized zirconium components had evidence of delamination. Cobalt chromium surface roughness significantly increased during the 2,000,000 cycle test, but oxidized zirconium surface roughness was not affected. Polyethylene wear was correlated to a significant degree with the surface roughness of the femoral components. The improved wear characteristics of the ceramic articular surfaces can be explained by the wettability of the ceramic surface, which minimized adhesive wear, and the resistance of the hard, ceramic surface to roughening.

Chromium Alloys↗