Transcriptome analysis reveals the molecular mechanism of hepatic metabolism disorder caused by chromium poisoning in chickens

Chromium (Cr) is one of the most important environmental pollutants which are released into the environment due to their wide usage in numerous industries. The excess of Cr (VI) can induce hepatotoxicity, while the molecular mechanism that is involved in Cr (VI)-induced hepatotoxicity is unclear. We demonstrated the induction of chromium poisoning model in chickens to identify the differentially expressed genes (DEGs), and their functions were analyzed under different physiological and pathological conditions. Histopathological examination and transcriptome data for chromium-poisoned livers and control livers were annotated with Illumina® HiSeq 2000. The histopathological examination in chromium poisoning groups showed diapedesis, hemolysis, degeneration, nucleus pycnosis, and central phlebectasia in the liver. A total of 334 genes were upregulated and 509 genes were downregulated. The most strongly upregulated genes were HKDC1, DDX4, ACACA, FDFT1, CYYR1, PPP1R3C, and SLC16A14, while the most downregulated genes were MYBPC3, CCKAR, PCK1, and CPT1A. A Gene Ontology (GO) term with the highest enrichment of DEGs is small molecule metabolic process. In cell component domain, the term with the highest enrichment is extracellular matrix. Kyoto Encyclopedia of Genes and Genomes (KEGG) pathways showed that glucose metabolism, lipid metabolism, and protein metabolism were the most important metabolic pathways in the liver. The current study first time provides important clues and evidence for identifying the differentially expressed genes in livers due to Cr (VI)-induced liver injury in chickens.

Do Dietary Habits Influence Trace Elements Release from Fixed Orthodontic Appliances?

The objective was to investigate the effect of dietary habits on the release of Cr and Ni ions from orthodontic appliances by hair mineral analysis. Patients (N = 47) underwent electronic questionnaire survey to investigate the effect of dietary habits on Cr and Ni levels in hair. The research was carried out on hair sampled at the beginning and in the 4th, 8th, and 12th months of the treatment. The content of Cr and Ni in the collected samples was determined by ICP-OES. The study showed that consumption of acidic dietary products may have the effect on increasing the release of Cr and Ni ions from orthodontic appliances. The release of Cr from orthodontic appliances in patients who consumed fruit juice, coffee, yoghurt, and vinegar was higher. The coefficients enabling comparison of metal ions release pattern at a given sampling points were defined. The comparison of the coefficients yielded the information on the possible magnification of metal ions released as the result of the additional factor consumption of acidic food or drink that intensifies metal ions release. The following magnification pattern was found for chromium: coffee (7.57 times) > yoghurt (2.53) > juice (1.86) > vinegar (1.08), and for nickel: vinegar (2.2) > coffee (1.22) > juice (1.05). Yoghurt did not intensify the release of nickel. Concluding, orthodontic patients should avoid drinking/eating coffee, yoghurt, fruit juices, and vinegar.

Effects of the Oral Administration of K2Cr2O7 and Na2SeO3 on Ca, Mg, Mn, Fe, Cu, and Zn Contents in the Heart, Liver, Spleen, and Kidney of Chickens

This study aimed to investigate the effects of selenium on the ion profiles in the heart, liver, spleen, and kidney through the oral administration of hexavalent chromium. Approximately 22.14 mg/kg b.w. K₂Cr₂O₇ was added to water to establish a chronic poisoning model. Different selenium levels (0.00, 0.31, 0.63, 1.25, 2.50, and 5.00 mg Na₂SeO₃/kg b.w.) around the safe dose were administered to the experimental group model. Ca, Mg, Mn, Fe, Cu, and Zn were detected in the organs through flame atomic absorption spectrometry after these organs were exposed to K₂Cr₂O₇ and Na₂SeO₃ for 14, 28, and 42 days. Results showed that these elements exhibited various changes. Ca contents declined in the heart, liver, and spleen. Ca contents also decreased on the 28th day and increased on the 42nd day in the kidney. Mn contents declined in the heart and spleen but increased in the kidney. Mn contents also decreased on the 28th day and increased on the 42nd day in the liver. Cu contents declined in the heart and spleen. Cu contents increased on the 28th day and decreased on the 42nd day in the liver and kidney. Zn contents declined in the heart and spleen. Zn contents increased on the 28th day and decreased on the 42nd day in the liver and kidney. Fe contents decreased in the heart and liver. Fe contents increased on the 28th day and decreased on the 42nd day in the spleen and kidney. Mg contents did not significantly change in these organs. Appropriate selenium contents enhanced Mn and Zn contents, which were declined by chromium. Conversely, appropriate selenium contents reduced Ca, Fe, and Cu contents, which were increased by chromium. In conclusion, the exposure of chickens to K₂Cr₂O₇ induced changes in different trace elements, and Na₂SeO₃ supplementation could alleviate this condition.

Severe metallosis and elevated chromium in serum following implantation of the joint unloading implant system

In recent years, the minimally invasive joint-preserving implant system has been developed. The main goal of this device is to unload the medial knee compartment without affecting the lateral compartment. The current authors describe a severe metallosis and elevated chromium in serum following implantation of the joint unloading implant system of a 50-year-old male patient, presented to our hospital 3 years after implantation of a KineSpring System into his left knee due to unicompartmental medial osteoarthritis (OA) in an external hospital. Radiographs showed radiological signs for loosening of the screws in the tibia and a progressive OA on the medial and patellofemoral compartments. Revision surgery with removing of the unloading device was performed at our hospital. The intraoperative situs presented a severe metallosis around the device. Five days after revision surgery, the laboratory parameters revealed an elevated value for chromium in serum, while nickel and cobalt values in serum were normal. Reliable clinical data about the long-term results of the KineSpring System is desperately needed. Further studies are warranted to work out the effects of cobalt and chromium levels and further side effects following the implantation of the extra-articular absorber system.

Metal-on-Metal Hip Joint Prostheses: a Retrospective Case Series Investigating the Association of Systemic Toxicity with Serum Cobalt and Chromium Concentrations

INTRODUCTION

There have been concerns about prosthesis failure and the potential for systemic toxicity due to release of cobalt and chromium from metal-on-metal hip joint prostheses (MoM-HP). There is conflicting evidence on whether there is a correlation between higher cobalt and chromium concentrations and systemic toxicity.

METHODS

We undertook a retrospective review of consecutive patients with MoM-HP referred for outpatient review in toxicology clinics in London, UK, and in the USA recorded in the Toxicology Investigators Consortium (ToxIC) Registry from June 2011 to June 2015.

RESULTS

Thirty-one cases were identified; the median (IQR) serum cobalt concentration was 10.0 (3.8-32.8) mcg/L, and the median (IQR) serum chromium concentration was 6.9 (3.7-18.7) mcg/L. Twenty-three (74.2%) had symptoms, most commonly lethargy, hearing loss, and tinnitus. The odds ratios of symptomatic/asymptomatic patients for metal ion concentrations above/below 7 mcg/L were 1.87 (95% CI 0.37-9.57, p = 0.45) and 0.60 (95% CI 0.10-3.50, p = 0.57) for cobalt and chromium, respectively. Two (6.5%) patients with systemic cobalt toxicity had median (IQR) serum cobalt concentrations significantly higher than those without systemic features (630.4 [397.6-863.2] mcg/L versus 9.8 [2.9-16.4] mcg/L; p = 0.017). However, overall, there were no differences between cobalt (p = 0.38) or chromium (p = 0.92) concentrations between symptomatic and asymptomatic patients and no clinical features or investigation results correlated with cobalt or chromium concentration.

CONCLUSION

Two (6.5%) of 31 individuals referred for assessment of MoM-HP were diagnosed with systemic cobalt toxicity. However, despite a high prevalence of reported symptoms, neither symptoms nor investigation results correlated with serum cobalt or chromium concentrations.

Application of ICP-MS and HPLC-ICP-MS for diagnosis and therapy of a severe intoxication with hexavalent chromium and inorganic arsenic

ICP-MS and HPLC-ICP-MS were applied for diagnosis and therapeutic monitoring in a severe intoxication with a liquid containing hexavalent chromium (Cr(VI)) and inorganic arsenic (iAs). In this rare case a liver transplantation of was considered as the only chance of survival. We developed and applied methods for the determination of Cr(VI) in erythrocytes and total chromium (Cr) and arsenic (As) in blood, plasma, urine and liver tissue by ICP-MS. Exposure to iAs was diagnosed by determination of iAs species and their metabolites in urine by anion exchange HPLC-ICP-MS. Three days after ingestion of the liquid the total Cr concentrations were 2180 and 1070μg/L in whole blood and plasma, respectively, and 4540μg/L Cr(VI) in erythrocytes. The arsenic concentration in blood was 206μg/L. The urinary As species concentrations were <0.5, 109, 115, 154 and 126μg/L for arsenobetaine, As(III), As(V), methylarsonate (V) and dimethylarsinate (V), respectively. Total Cr and As concentrations in the explanted liver were 11.7 and 0.9mg/kg, respectively. Further analytical results of this case study are tabulated and provide valuable data for physicians and toxicologists.

Content of trace elements and chromium speciation in Neem powder and tea infusions

Total concentrations of selected trace elements in Neem powder and in Neem tea were determined by inductively coupled plasma mass spectrometry (ICP-MS). The data revealed that despite high total concentrations of the potentially toxic elements Al and Ni in Neem powder, their amounts dissolved in Neem tea were low. Total concentrations of the other toxic elements Pb, As and Cd were also very low and do not represent a health hazard. In contrast, total concentrations of the essential elements Fe, Cu, Zn, Se Mo and Cr in Neem powder were high and also considerable in Neem tea. Consuming one cup of Neem tea (2g per 200 mL of water) covers the recommended daily intakes for Cr and Se and represents an important source of Mo and Cu. Speciation analysis of Cr by high performance liquid chromatography (HPLC) coupled to ICP-MS with the use of enriched Cr isotopic tracers to follow species interconversions during the analytical procedure demonstrated that toxic Cr(VI) was not present either in Neem powder or in Neem tea. Its concentrations were below the limits of detection of the HPLC-ICP-MS procedure applied. The speciation analysis data confirmed that even Cr(VI) was added, it was rapidly reduced by the presence of antioxidants in Neem leaves. By the use of enriched Cr isotopic spike solutions it was also demonstrated that for obtaining reliable analytical data it is essential to apply the extraction procedures which prevent Cr species interconversions, or to correct for species transformation.

[Heavy metal poisoning and renal injury in children]

Along with global environmental pollution resulting from economic development, heavy metal poisoning in children has become an increasingly serious health problem in the world. It can lead to renal injury, which tends to be misdiagnosed due to the lack of obvious or specific early clinical manifestations in children. Early prevention, diagnosis and intervention are valuable for the recovery of renal function and children's good health and growth. This paper reviews the mechanism of renal injury caused by heavy metal poisoning in children, as well as the clinical manifestations, diagnosis, and prevention and treatment of renal injury caused by lead, mercury, cadmium, and chromium.

Outline of occupational chromium poisoning in China

The present study analyzed the feature of occupational chromium poisoning in China since the 1980s. The collected data were acquired from 18 previous surveys of chromium poisoning in 14 cities of China. The method of risk assessment was applied to calculate the relative risk and 95% CI, p < 0.05 was considered as a significant risk. The results showed that nasal disease was the most common sign of occupational chromium poisoning, and the prevalence rate of nasal disease was 17.83% in total population of 6,998. Further, the risk analysis showed that occupational chromium poisoning led to an increased risk of lung or liver cancer in male workers due to the definite carcinogenicity of hexavalent chromium. Significantly, an increased risk of spontaneous or threatened abortion was also found in female workers. In conclusion, these studies suggest that early detection of impaired reproductive function or impaired lung or liver function in female or male workers is essential for controlling occupational chromium poisoning in China.

Assessment of the mode of action underlying development of rodent small intestinal tumors following oral exposure to hexavalent chromium and relevance to humans

Abstract Chronic exposure to high concentrations of hexavalent chromium (Cr(VI)) in drinking water causes intestinal adenomas and carcinomas in mice, but not in rats. Cr(VI) causes damage to intestinal villi and crypt hyperplasia in mice after only one week of exposure. After two years of exposure, intestinal damage and crypt hyperplasia are evident in mice (but not rats), as are intestinal tumors. Although Cr(VI) has genotoxic properties, these findings suggest that intestinal tumors in mice arise as a result of chronic mucosal injury. To better understand the mode of action (MOA) of Cr(VI) in the intestine, a 90-day drinking water study was conducted to collect histological, biochemical, toxicogenomic and pharmacokinetic data in intestinal tissues. Using MOA analyses and human relevance frameworks proposed by national and international regulatory agencies, the weight of evidence supports a cytotoxic MOA with the following key events: (a) absorption of Cr(VI) from the intestinal lumen, (b) toxicity to intestinal villi, (c) crypt regenerative hyperplasia and (d) clonal expansion of mutations within the crypt stem cells, resulting in late onset tumorigenesis. This article summarizes the data supporting each key event in the MOA, as well as data that argue against a mutagenic MOA for Cr(VI)-induced intestinal tumors.

[Re-evaluation of the fundamentals of trace elements]

The roles of trace elements have been extensively studied for decades. However, recent advances in both molecular and epidemiological studies on trace elements have provided new information and concepts on the actions of trace elements. Some of our fundamental knowledge on the roles of trace elements based on classical data should be replaced by new concept based on new findings. This series of "Re-evaluation of the Fundamentals of Trace Elements" aims to provide new fundamentals on trace elements by reviewing rapidly advancing knowledge in this study area. The first article is a critical review on the role of chromium in human nutrition.

Biomonitoring of genotoxic effects among shielded manual metal arc welders

Hexavalent chromium Cr (VI) used in shielded metal arc welding is widely recognized to act as a carcinogen, mutagen and teratogen. The carcinogenic potential of metals is a major issue in defining human health risk from exposure. Hence in the present investigation, 66 welders and 60 control subjects with similar mean ages, smoking prevalences and alcohol consumption were enrolled for DNA damage analysis of buccal cells by micronucleus (MN) and comet assay. Welders showed a significant increase in micronucleated cells compared to controls and a larger mean comet tail length. The current study thus suggested that chronic occupational exposure to Cr (VI) during welding could lead to increased level of DNA damage. Understanding the complexity of the relationships between exposure, basal DNA damage and MN frequencies requires larger scale studies and application of complementary biomarkers.

Acute severe chromium poisoning after dermal exposure to hexavalent chromium

Severe acute chromium poisoning related to dermal involvement has rarely been reported in the literature. We report a case of acute severe chromium poisoning through skin exposure as a result of a chemical burn of 15% of the body surface area and multiple organ failure after short-term exposure. Medical interventions, including mechanical ventilation, continuous venovenous hemofiltration, and plasmapheresis were performed. In addition, a chelating agent, dimercaptopropane sulfonic acid, was infused intravenously, combined with intravenous N-acetylcysteine and ascorbic acid as adjuvant therapy. The patient was discharged on day 33 without long-term sequelae. The consequence of transdermal exposure of hexavalent chromium should not be overlooked.

Effect of chromium on the level of IL-12 and IFN-gamma in occupationally exposed workers

Chromium may affect humoral and cellular immunity, acting on T lymphocytes as well as on granulocytes and monocytes cells. Cytokines play an important role in the immune balance. In this study, the level of IL-12 and IFN-gamma were evaluated in the sera and PHA/LPS stimulated culture supernatant of human PBMCs of healthy volunteers and occupationally exposed chromium workers. All the workers were highly exposed to chromium having mean of 104.65+/-77.21 microg/dL (range 23.7-316.8 microg/dL). A suspension of exposed and unexposed human PBMC (0.5x10(6) cells/ml) prepared and cultured in RPMI-1640 supplemented with 10% FCS for 18 h in the presence or absence of LPS (10 ng/ml) which used for stimulation of IL-12 and IFN-gamma. The level of IL-12 and IFN-gamma were evaluated in the sera samples as well as LPS stimulated and unstimulated culture supernatant of h-PBMCs of chromium exposed workers. In these chromium exposed workers the level of IL-12 was 433.66+/-197.49 pg/ml and 983.45+/-330.99 pg/ml in LPS stimulated culture supernatant of normal individuals and highly chromium exposed workers, which was significant (P<0.05). Although the level of IL-12 was (78.61+/-61.03 pg/ml to 146.52+/-46.37 pg/ml) elevated in unstimulated culture supernatant of h-PBMCs of chromium exposed individuals as compared to control, but it was not significant. This observation also suggests that a significant increase in IFN-gamma production in LPS stimulated and unstimulated culture supernatant of h-PBMCs of chromium exposed workers as compared to control. However, IFN-gamma level have a significant positive correlation between blood chromium level (r=0.833, t=6.3872, P 0.05) and exposure time (in years) (r=0.8916, t=8.3540, P 0.05) of the occupationally exposed workers.

Cellular responses in the cyprinid Leuciscus cephalus from a contaminated freshwater ecosystem

The response of wild chubs (Leuciscus cephalus) to chemical pollution was assessed in a metal contaminated river (Cecina River, Italy) through a wide battery of biomarkers which included: Comet assay detecting DNA strand breaks; diffusion assay for apoptosis induction; micronucleus test assessing chromosomal alterations; ethoxyresorufin O-deethylase (EROD) activity for the induction of cytochrome P 4501A; acetylcholinesterase (AChE) activity responsive to pesticide exposure; vitellogenin gene expression in males revealing estrogenic effects. Bioaccumulation of mercury, chromium and polycyclic aromatic hydrocarbons (PAHs) was also determined. Levels of mercury and PAHs were higher in tissues of chubs sampled from the most downstream station, reflecting an anthropogenic pollution of industrial origin. Otherwise, accumulation of Cr was quite similar in fish along the entire course of Cecina River confirming a natural origin due to local geochemical features. Biomarker responses revealed a significant increase of apoptotic cells, DNA stand breaks and micronucleus frequency in chubs from the more impacted sites. A slight EROD induction and AChE inhibition were only seen at the most downstream station demonstrating a limited impact due to PAHs and pesticides. On the other hand, the induction of vitellogenin gene in male chubs was measured in all the sites, suggesting a diffuse estrogenic effect. This study confirmed the utility of large batteries of biomarkers in biomonitoring studies and the suitability of wild chub as bioindicator organism for river basins.

Suppression of IL-6 level in human peripheral blood mononuclear cells stimulated with PHA/LPS after occupational exposure to chromium

The toxic metals alter the immune response of animals as well as humans. In addition to the well documented and numerous toxic effect of chromium on various target organs, number of studies shown that acute and chronic exposure to inorganic chromium may result in impairment of immune functions in the experimental systems. Immunosuppression appears to be more subtle effect of exposure to heavy metals. Therefore, we have taken two different groups of chromium exposed individuals. These were leather tanning workers and chromeplaters. These groups of individuals were regularly exposed to chromium. All the leather tanning workers were highly exposed to chromium having a mean of 96.60+/-113.95 mg/dl (range 12.4-417.21 mg/dl). A suspension of exposed and unexposed human PBMC (0.5x10(6) cells/ml) prepared and cultured in RPMI-1640 supplemented with 10% FCS for 18 h in the presence or absence of PHA (5 microg/ml) and LPS (10 ng/ml) which used for stimulation of IL-2, IL-4, TNF-alpha, IL-10 and IL-6, respectively. The levels of Th1/Th2 cytokine: IL-2, IL-4, TNF-alpha, IL-10 and IL-6 were evaluated in the sera and PHA/LPS stimulated culture supernatant of human PBMCs of chromium exposed workers. In these workers the level of IL-6 was 543.95+/-123.75 pg/ml and 388.40+/-61.24 pg/ml in PHA/LPS stimulated culture supernatant of normal individuals and highly chromium exposed workers, which was significant (P<0.05). This observation suggests that IL-6 levels were suppressed in chromium exposed groups as compared to unexposed healthy volunteers. Although the level of IL-2 in PHA stimulated culture supernatant of PBMCs was suppressed in chromium exposed individuals but it was not significant, IL-4 and IL-10 could not be detected. However, there was no difference in TNF-alpha levels in sera samples as well as unstimulated culture supernatant of h-PBMCs of chromium exposed individuals as compared to control.

The risk-benefit balance in the United States: who decides?

A health policy decision often requires a balancing of risks, costs, and benefits. In this paper we illustrate that there is no uniform answer in the United States to the question of who decides the risk-benefit balance. We use a wide range of case examples from medicine and public health to show the different approaches that are used to allocate decision-making responsibility. Our ultimate purpose is to urge the U.S. health policy community to develop a more consistent way of thinking about how risk-benefit decisions could be guided by general principles.

In vivo spermatotoxic effect of chromium as reflected in the epididymal epithelial principal cells, basal cells, and intraepithelial macrophages of a nonhuman primate (Macaca radiata Geoffroy)

OBJECTIVE

To understand, through a simulation experiment in a nonhuman primate model, the potential in vivo spermatotoxic toxic effect of hexavalent chromium (CrVI) in men who are occupationally or environmentally exposed to it.

DESIGN

Controlled laboratory study.

SETTING

Research laboratory in a department of endocrinology in a university in India.

ANIMAL(S)

Male bonnet monkey, Macaca radiata Geoffroy.

INTERVENTION(S)

Monkeys were exposed ad libitum to 100, 200, and 400 ppm CrVI, dissolved in drinking water, for a chronic period of 180 days.

MAIN OUTCOME MEASURE(S)

Examination of epididymis with a transmission electron microscope and assessment of the effect of CrVI in terms of accumulation of sperm-derived lipofuscin (LF) material in the principal cells, basal cells, and intraepithelial macrophages of the epithelium.

RESULT(S)

The abundance of basal cells and intraepithelial macrophages and the content of LF material in these cell types increased. The principal cells phagocytosed from the lumen the dead sperm resulting from CrVI exposure and processed them partially into LF material, which was acquired by the basal cells and intraepithelial macrophages and processed further. The LF material-laden basal cells and intraepithelial macrophages appeared to leave the epithelium, accompanied by recruitment of fresh basal cells and intraepithelial macrophages.

CONCLUSION(S)

Occupational or environmental exposure to CrVI, as would occur in the tannery, soap, and other industries in developing and underdeveloped countries, can be toxic in vivo to spermatozoa.

Prevention of chromate induced oxidative stress by alpha-lipoic acid

The parenteral administration of alpha-lipoic acid (LA) protected against chromate induced oxidative stress in mouse liver. A shift in Cr induced pro-oxidant state to antioxidant-state by LA was noteworthy. The degree of protection was significant and similar in different LA administration regimens (prior-, co- and post- parenteral Cr exposure) explored. An improved status of the tissue antioxidants by LA appeared to be the mechanism of mitigation. The results are of chemopreventive value and suggest a possible alternative to ascorbic acid for abrogation of Cr toxicity.

Lung cancer in relation to occupational and environmental chromium exposure and smoking

The increased occurrence of lung cancer in residents of Dolny Kubin, the North-Slovakia district with ferrochromium industry, compared to the general population of Slovakia, led us to the study assessing influence of the occupational and environmantal exposure to chromium on the lung cancer incidence, respecting also the risk coming from cigarette smoking. Residents of Dolny Kubin district with the diagnosed lung cancer in 1984-1999 were involved in the study. The occurrence of lung cancer was significantly higher in people working in ferrochromium industry. The age at the onset of the disease in people exposed to chromium was by 5.5 years lower than in non-exposed. Smoking was an important risk factor, which has been proved particularly in non-exposed group where 62% were smokers and the onset of the lung cancer in them occured about 3.4 years earlier than in non-smokers. In exposed groups, no significant effect of smoking was found. We can conclude, that occupational exposure to chromium was identified as the main risk factor of lung cancer in Dolny Kubin district even overlaying effect of smoking.

Estimating historical occupational exposure to airborne hexavalent chromium in a chromate production plant: 1940--1972

This article presents a retrospective exposure assessment for 493 workers who were occupationally exposed to airborne hexavalent chromium, Cr(VI), at a Painesville, Ohio, chromate production plant from 1940-1972. Exposure estimates were reconstructed using a job-exposure matrix approach that related job titles with area monitoring data from 21 industrial hygiene surveys conducted from 1943 to 1971. No personal monitoring data were collected. Specifically, airborne Cr(VI) concentration profiles for 22 areas of the plant, termed job-exposure group (JEG) areas, were constructed for three distinct time periods (1940-1949, 1950-1964, and 1965-1972), with cut points based on known major plant and process changes. Average airborne Cr(VI) concentrations were the highest for the bridge crane operators (5.5 mg/m3) prior to 1965, although only four cohort members held this job title. Airborne concentrations for the rest of the production areas of the plant ranged from 1.9 mg/m3 for packers in the 1940s to 0.012 mg/m3 for ore mill operators after 1964. For nearly all JEG areas, exposures decreased over time, particularly after 1964. For example, average airborne concentrations in production areas of the plant decreased from 0.72 mg/m3 in the 1940s to 0.27 mg/m3 from 1950 to 1964, and the average was 0.039 mg/m3 after 1964. Former workers were interviewed to determine activity patterns in the plant by job title. This information was combined with Cr(VI) monitoring data to calculate cumulative occupational exposure for each worker. Cumulative exposures ranged from 0.003 to 23 (mg/m3) x years. The highest monthly 8-hour average exposure concentration for each worker ranged from 0.003 to 4.1 mg/m3. These exposure estimates have been combined with mortality data for this cohort to assess the lung cancer risk associated with inhaled Cr(VI), and a positive dose-response relationship was observed for increases in lung cancer mortality with measures of cumulative exposure and highest monthly exposure.

Individual susceptibility to hexavalent chromium of workers of shoe, hide, and leather industries. Immunological pattern of HLA-B8, DR3-positive subjects

BACKGROUND

This study was designed to examine the effects of hexavalent chromium [Cr(VI)] on the immunological pattern of shoe, hide, and leather industry workers, moving from the hypothesis that some haplotypes (HLA-B8,DR3) can be important hidden risk cofactors.

METHODS

Workplaces of 20 firms were monitored for total and respirable dusts and for total and hexavalent chromium. Cr(VI) on materials was also measured. Assay of chromium levels in blood and urine of 44 serological human leukocytes antigen (HLA)-typed workers (20 exposed, 15 HLA-B8,DR3-negative/5-positive and 24 non-exposed, 18 HLA-B8,DR3-negative/6-positive subjects) was performed by atomic absorption, and lymphocyte subsets (FACS-analysis), mitogen-mediate lympho-proliferation ([3H]thymidine incorporation), cytokine levels (ELISA), natural killer (NK) cytotoxic activity (51Cr-release assay) were determined.

RESULTS

The environmental parameter levels are lower than threshold limit value-time-weighted average (TLV-TWA); in the materials, the Cr(VI) values exceeded the levels allowed. The peripheral blood mononuclear cells (PBMC) proliferation and the T-helper1 (TH1) cytokine pattern of subjects chronically exposed were significantly raised; addition in vitro of Cr(VI) further stimulated these parameters and in general the entire TH1 system and NK activity. The TH2 system was unaltered. In the HLA-B8,DR3-positive workers, immunologically "low responders", the addition of Cr(VI) in vitro caused a further reduction of the considered parameters in the exposed subjects with a dramatic deficit of the TH1 system.

CONCLUSIONS

Results indicate the unsuitability of TLV-TWA as a line of demarcation between safe and dangerous Cr(VI) concentrations and the importance of individual genetic susceptibility for occupational and preventative medicine. In particular, the presence of the HLA-B8,DR3 alleles can represent an important cofactor of immunotoxic susceptibility consequent to chronic low-dose Cr(VI) exposure.

Sampling and analysis considerations for the determination of hexavalent chromium in workplace air

Airborne hexavalent chromium (Cr[VI]) is a known human respiratory carcinogen and allergen. Workers in a variety of industries may be exposed to airborne hexavalent chromium, with exposures frequently occurring via inhalation and/or dermal contact. Analytical methods for the measurement of Cr(VI) compounds in workplace samples, rather than for the determination of total elemental chromium in workplace air, are often desired because exposure limit values for Cr(VI) compounds are much lower than for total Cr. For years, sampling and analytical test methods for airborne Cr(VI) have been investigated so as to provide means for occupational exposure assessment to this highly toxic species. Inter-conversion of trivalent chromium (Cr[III]) and Cr(VI) can sometimes occur during sampling and sample preparation, and efforts to minimize unwanted redox reactions involving these chromium valences have been sought. Because of differences in toxicity, there is also interest in the ability to differentiate between water-soluble and insoluble forms of Cr(VI), and procedures that provide solubility information concerning Cr(VI) compounds have been developed. This paper reviews the state of the art concerning the measurement of airborne Cr(VI) compounds in workplace aerosols and related samples.

Oxidative Stress,hogg1Expression and NF‐κB Activity in Cells Exposed to Low Level Chromium

Chromium compounds are carcinogenic to the human lung, although the detailed biochemical mechanism is still unclear. To understand the carcinogenic mechanism in cells exposed to low level hexavalent chromium, we measured the generation of reactive oxygen species (ROS) and 8-hydroxydeoxyguanosine (8-OH-dG), the transcription of hogg1, which encodes an 8-OH-dG repair protein, and NF-kappaB activation levels in the A549 human lung epithelial cell line after exposure to Cr (VI) at concentrations of 12.5 to 800 microM. In A549 cells, ROS levels and DNA binding by NF-kappaB increased in proportion to the concentration of Cr (VI). These increases were diminished by pretreatment with catalase, superoxide dismutase, or D-mannitol, but the levels of 8-OH-dG and expression of hogg1 did not change significantly with Cr (VI) exposure. These results suggest that the induction of ROS and the activation of NF-kappaB are important in the carcinogenic mechanism of Cr (VI), but it is unlikely that Cr (VI) concentrations below 800 microM increase 8-OH-dG levels or the expression of hogg1.

Risk assessment of chromium and arsenic in date palm leaves used as livestock feed

Appreciable levels of total chromium (Cr) and arsenic (As) were found (by emission spectroscopy) in date palm leaves, which form a significant ingredient in livestock feed. The levels in the fruit were considered safe for human consumption. Our work involved evaluation of the distribution of these elements in the leaves during the developmental stages of the fruiting season. Thirty-six leaf specimens of the Fard cultivar were collected 9, 15 and 20 weeks, respectively, after pollination and subjected to a standard digestion procedure. Sample masses of typically 1 g (dry weight) were prepared in 25 ml dilute acid solution and investigated for trace levels of Cr and As by ICP-AES. Eleven soil samples collected at random during the growth stages were subjected to a similar digestion procedure and analysis. According to the literature, the permissible mean levels of Cr and As in plants are 200 and 80 ng/g (dry weight), respectively. We used these values as our guideline to assess the "risk" levels in our samples of interest. In the case of Cr, about 45% of the specimens possessed levels between 250 and 700 ng/g, while a significant number produced levels between 1000 and 5000 ng/g. With regard to As, about 70% of the samples were above the documented permissible mean value. As a result of the unusually high Cr concentrations in some cases, the feasibility of Cr "accumulation" in the leaves was examined. Insects and other organisms subsist on the leaves and an added concern was the accumulation of these elements in the food chain. The study formed an interesting contribution to environmental research, and the impact of our assessment on the environment is discussed.

MARS procedure as a bridge to combined liver-kidney transplantation in severe chromium-copper acute intoxication: a paediatric case report

We describe a case of multi-organ failure (liver-kidney insufficiency and brain oedema) caused by accidental, acute intoxication with a chromium and copper-containing substance, as an example of the introduction of the new extracorporeal procedure MARS (molecular adsorbents recirculating system) in a girl 3.5 years old.

Kinetics of an intratracheally administered chromium catalyst in rats

Chromium-based catalysts are used for the synthesis of polyethylene, but little is known about the hazard and biomonitoring possibilities of this type of chromium for workers who may be occupationally exposed to such compounds. Therefore, the bioavailability and toxicokinetics of chromium were studied in male Wistar rats after a single intratracheal instillation (2 ml/kg body weight) of various doses (1, 5, or 25 mg/kg body weight) of the catalyst (approximately 1% chromium bound to an amorphous silica matrix), either before (CAT-Cr[III]) or after (CAT-Cr[VI]) heat treatment. The results were compared with those of equivalent amounts of two chromium salts (CrCl(3) and K(2) Cr(2) O (7). Each dose group was composed of three rats. The concentration of chromium was determined by atomic absorption spectrometry in urine (collected daily for 7 d) and in plasma, erythrocytes, lung, and liver tissue obtained 2 d (only highest concentration) and 7 d after dosing. On d 2, a significant increase in lung weight was found in the animals treated with the highest dose of the hexavalent Cr products. On d 7, on the basis of body weights, lung weights, and lung histology, there was no overt toxicity, except after the highest dose of CAT-Cr(VI). The elimination of all forms of chromium was apparently monoexponential, with calculated half-life elimination times in urine of 4-11 h for Cr(III) (CAT-Cr[III] and CrCl3 ) and 8-21 h for Cr(VI) (CAT-Cr[VI] and K(2) Cr(2) O(7). On d 2, the erythro-cytes Cr concentrations were significantly higher for the hexavalent Cr products than for the trivalent Cr products. After 7 d, the erythrocytes Cr concentrations were significantly increased above control values (3 microg/L) only in rats treated with the 2 highest doses of Cr( VI) compounds (12 and 64 microg/L for K(2) Cr(2) O(7), and 14 and 79 microg/L for CAT-Cr[VI]). The present study shows that intratracheally instilled Cr(VI) and Cr(III) have different toxicokinetic profiles and that the Cr(VI) catalyst has the same bioavailability and excretion kinetics as a water-soluble Cr(VI) salt. Exposure to chromium compounds could be monitored by measuring Cr concen-trations in urine (shortly after exposure) and in erythrocytes (also at later time points after high Cr[VI] exposure).

[Poisoning by chromium and its long lasting detoxication]

Long lasting influence of cumulated Cr provide irreversible damages of vascular walls, organs and their systems. During long lasting treatment most of Cr is removed during the first 20 days through bileric tract and at the same time through the renal tract the Cr amounts decreases because chromium-d-penicilamin complex in hepatocytes induces synthesis of specific chromium-d-penicilamin binding labile protein and they are removed with bile. The levels of essential microelements (Cu and Zn) are maintained at the level of the physiological tolerance during treatment. Cr removes very slowly (about a year) from human body, and after treatment patients health do not improve because Cr-inducted damages of vascullars, organs and their systems are not recovered. The treatment must be evaluated continuously by controlling concentrations' of Cr, Cu, Zn and other microelements in the blood, plasma and urine by electrothermal atomic absorbtion spectrophotometry methods.

[Effects of biologically active food additives on digestive function in experimental lead and chromium poisoning]

Biologically active additives in the Multi-Green and Licorice foods were studied for effects on digestive function upon 100-day experimental intoxication with lead and chromium in a dose of 5 mg/kg. The metals were found to produce local irritating and inflammatory effects on the intestinal mucosa and a resorptive toxic effects on pancreatocytic function. Multi-Green and Licorice diminished the manifestations of adverse effects of lead and chromium on the functional status of digestive organs.

Suicide by ingestion of a CCA wood preservative

Chromated-copper-arsenate (CCA) is a compound used worldwide for wood preservation. Occupational hazards from chronic exposure to CCA are well known, but acute ingestion of CCA wood preservative is very rare. We describe a case of suicide by ingestion of a CCA wood preservative. A 33-year-old man attempted suicide by ingesting an unknown liquid, later identified as a CCA wood preservative, 75 min before his arrival in the emergency department. He was in severe respiratory distress, drooling, tachycardic, and hypotensive. There was an orange color on the palms of both hands. Severe, green colored burns of the buccal mucosa were observed. He was intubated shortly after arrival. The larynx was edematous, but a 7-mm endotracheal tube was successfully introduced. Blood tests revealed partially compensated metabolic acidosis. The patient deteriorated rapidly; the systolic blood pressure dropped to 70 mmHg, and he passed bloody diarrhea. He developed multiple premature atrial contractions and supraventricular tachycardia, and later in the intensive care unit, refractory ventricular tachycardia and ventricular fibrillation. The patient was declared dead 212 h after his arrival. Unfortunately, postmortem blood levels of heavy metals and autopsy were not performed because of refusal by the family for religious reasons.

Chromic acid burns: early aggressive excision is the best method to prevent systemic toxicity

Chromium poisoning can occur from the cutaneous absorption of chromium from burns that are as small as 1% of the total body surface area. In this case report, we describe a patient with 10% total body surface area burns caused by hot chromic acid. The amount of chromium removed by peritoneal dialysis and the amount of chromium in the urine were estimated, as well as the chromium content in the excised skin, serum, and red blood cells. The extent of chromium load from this type of injury and subsequent risk of systemic poisoning is not predictable, and we therefore believe that systemic toxicity is best prevented by early excision of the burned skin.

Therapeutic review: is ascorbic acid of value in chromium poisoning and chromium dermatitis?

INTRODUCTION

Repeated topical exposure to chromium(VI) may cause an allergic contact dermatitis or the formation of chrome ulcers. Systemic toxicity may occur following the ingestion of a chromium(VI) salt, from chromium(VI)-induced skin burns, or from inhalation of chromium(VI) occurring occupationally. Soluble chromium(VI) salts are usually absorbed more easily and cross cell membranes more readily than trivalent chromium salts, and, therefore chromium(VI) is more toxic than chromium(III). In experimental studies, endogenous ascorbic acid in rat lung, liver, and kidney and human plasma, effectively reduces chromium(VI) to chromium(III). The administration of exogenous ascorbic acid has been advocated therefore in the treatment of systemic chromium poisoning and chromium dermatitis to enhance the extracellular reduction of chromium(VI) to the less bioavailable chromium(III).

REVIEW

In vitro experiments confirm that the addition of ascorbic acid to plasma containing chromium(VI) leads to a dose-dependent reduction of chromium(VI) to chromium(III). In animal studies, parenteral ascorbic acid 0.5-5 g/kg significantly reduced chromium-induced nephrotoxicity when administered 30 minutes before parenteral sodium dichromate and up to 1 hour after parenteral sodium chromate dosing. Parenteral ascorbic acid 0.5-5 g/kg also reduced mortality when given orally up to 2 hours after oral potassium dichromate dosing. However, the administration of parenteral ascorbic acid more than 2 hours after parenteral chromate in these experimental studies did not protect against renal damage, and parenteral ascorbic acid given 3 hours postparenteral chromate increased toxicity. In addition, there is no confirmed clinical evidence that the administration of ascorbic acid lessens morbidity or mortality in systemic chromium poisoning. A possible reason for the lack of benefit of ascorbic acid when administration is delayed, is that chromium(VI) cellular uptake has occurred prior to ascorbic acid administration. Topical 10% ascorbic acid has been claimed to reduce significantly the healing time of experimentally induced chrome ulcers in guinea pigs. The proposed mechanism is reduction on the skin surface of chromium(VI) to chromium(III). Several case reports suggest that topical ascorbic acid is effective in the management of chromium dermatitis but this has not been confirmed in controlled clinical trials and, moreover, the practical difficulties of frequent application are likely to limit its usefulness.

DISCUSSION

Based on experimental studies, substantial amounts of ascorbic acid would need to be administered, preferably parenterally, soon after exposure to prevent systemic toxicity from chromium(VI) in humans. However, as ascorbic acid is a metabolic precursor of oxalate, the administration of ascorbic acid in high dose could lead to acute oxalate nephropathy, particularly in the presence of renal failure. While smaller doses of ascorbic acid (e.g., 10 g intravenously) are not toxic, such doses probably will not reduce the mortality from systemic chromium poisoning.

CONCLUSION

There is currently insufficient evidence to advocate the use of ascorbic acid in the management of systemic chromium toxicity. Topical ascorbic acid may reduce dermal hexavalent chromium exposure, but this observation must be confirmed in controlled studies.

Chromium induced contact dermatitis and indices for diagnosis

Chromium exposure plays an important role in development of contact dermatitis. The prevalence of contact dermatitis among tannery workers and cement-exposed workers is high. This study was designed to determine the prevalence of contact dermatitis among some Egyptian workers exposed to chromium and to investigate the role of patch test and IgE immunoassay in diagnosis of contact dermatitis. Eighty-three male workers who were exposed to chromium were selected after application of certain exclusion criteria to be the target population of this study. Forty male workers away from exposure to chromium were taken to be the controls. All the exposed and non exposed workers were investigated through an interview questionnaire, clinical examination, patch test and determination of blood and urine chromium levels, absolute eosinophilic count and total IgE level. The results showed that there was no significant difference between exposed workers with clinically diagnosed contact dermatitis and the clinically free exposed workers regarding age and work duration. 7.7% of exposed workers with positive patch test suffered from contact dermatitis while 31.6% of exposed workers with negative patch test suffered from contact dermatitis. There was no statistically significant difference between clinically diagnosed contact dermatitis workers and clinically free workers regarding blood and urine chromium levels. IgE level and absolute eosinophilic count were statistically higher among exposed workers with contact dermatitis than among clinically free exposed workers. According to the results of this study, it is concluded that the diagnosis of skin hypersensitivity to chromium should depend upon the history of chromium exposure, clinical examination and a battery of investigations including IgE level, eosinophilic count and patch test.

Identification of free radical formation and F2-isoprostanes in vivo by acute Cr(VI) poisoning

We previously reported the detection of a carbon-centered radical adduct of alpha-(4-pyridyl 1-oxide)-N-tert-butylnitrone (POBN) in the bile of rats acutely poisoned with Cr(VI) utilizing an electron spin resonance spin-trapping technique. These former studies suggested that the free radical metabolite was derived from a polyunsaturated fatty acid. The present studies were undertaken to further characterize this radical adduct and to determine whether its formation is associated with enhanced lipid peroxidation in vivo. This report demonstrates that electron spin resonance (ESR) spectra with hyperfine coupling constants aN of 15.71 G and of 2.90 G were present in bile from Cr(VI)-poisoned rats. We found out that virtually identical ESR spectra were obtained when authentic POBN-pentyl radical adducts generated from the reaction of POBN with either pentylhydrazine or linoleic or arachidonic acid with lipoxygenase were added to bile. The hyperfine coupling constants for the POBN-pentyl radical adducts added to bile were as follows: aN = 15.85 G and = 2.60 G for the reaction between pentylhydrazine and POBN; aN = 15.72 G and = 2.61 G for the reaction between arachidonic acid, lipoxygenase, and POBN; and aN = 15.85 G and = 2. 85 G for the reaction between linoleic acid, lipoxygenase, and POBN. In addition, the formation of this radical adduct was associated with lipid peroxidation as quantified by increases in F2-isoprostane levels in bile. These studies, therefore, provide additional evidence that acute Cr(VI) poisoning is associated with enhanced generation of F2-isoprostanes in vivo and tentatively identify the radical species that is produced as the POBN-pentyl radical adduct.

Elevated serum levels of pantropic p53 proteins in chromium workers

OBJECTIVES

This study investigated the possibility of applying serum pantropic p53 proteins in molecular epidemiologic studies, as a biomarker of environmental carcinogenesis. The serum levels of pantropic p53 proteins were determined in workers with past exposure to hexavalent chromium compounds.

METHODS

Thirty-one male workers occupationally exposed to hexavalent chromium compounds in the production of chromium compounds for 0 to 23 years served as the exposed group. The referents were 10 volunteers without work-related exposure to chemicals. In the determination of pantropic p53 proteins, commercially available kits for enzyme-linked immunosorbent assay were used which quantitatively detected both mutant and wild-type human p53 proteins.

RESULTS

The serum level of pantropic p53 proteins was in the range of 116.4 to 1122.6 pg/ml for the exposed workers and of 117.4 to 305.8 pg/ml for the referents. Nineteen percent of the exposed workers had a high p53 protein level (6 out of 31) when compared with the referents. All but 1 of the 6 workers had been occupationally exposed to chromium compounds for more than 11 years. Two of the 3 workers with a past history of lung cancer also showed high levels.

CONCLUSIONS

Our findings confirm that the application of p53 proteins as a biomarker of environmental carcinogenesis merits further exploration.

[Is chromium an essential or a toxic element?]

Chromium holds a frequent and important place in toxicological literature. The large number of more or less important toxicological facts (e.g. allergic dermatoses, ulcer, perforations of the nasal septum, bronchitis, cancerogenity etc.) are the reason why chromium is conceived rather as a toxic element. On the other hand in the non-toxicological literature favourable actions of chromium are described (its relationship to carbohydrate utilization, the glucose tolerance factor, diabetes etc.) which may induce us to consider chromium an essential element. Is chromium toxic or essential? It is both. The concept of essential or toxic cannot be conceived statically, these terms are relative and depend on a number of other facts and data (dose, time, chemical form, individuality of the organism, interaction with other substances in the environment etc). This relative view has a more general validity not only for chromium but for trace elements in general and it is very important in particular with regard to prevention of health damage caused by deficiency or excess of a substance.

Elevated incidence of childhood leukemia in Woburn, Massachusetts: NIEHS Superfund Basic Research Program searches for causes

Between 1966 and 1986, the childhood leukemia rate in Woburn, Massachusetts, was 4-fold higher than the national average. A multidisciplinary research team from MIT, which is being supported by the NIEHS Superfund Basic Research Program, has explored the possible importance of a temporal correlation between the period of elevated leukemia and a previously unrecognized mobilization of toxic metals from a waste disposal site in north Woburn. Residents of Woburn may have been exposed to arsenic (70 micrograms/l) and chromium (240 micrograms/l) at levels in excess of federal drinking water standards (50 micrograms/l for each metal) by consuming municipal groundwater contaminated with these metals. Research is currently underway a) to elucidate the mechanisms and the pathways by which these metals were transported from the waste disposal site to the drinking water supply; b) to determine the identity of the principal human cell mutagens in samples of aquifer materials collected from the site of the municipal supply wells; and c) to measure the extent of exposure and genetic change in residents who consumed the contaminated well water.

Plasma mass spectrometry as a detector for chemical speciation studies

Inductively coupled plasma mass spectrometry (ICP-MS), when coupled with the unique separating power of various chromatographic techniques, allows the detection of various elements at ultra-trace levels. The investigation of various toxic elements of environmental concern coupling relatively recent techniques, such as supercritical fluid chromatography (SFC) and capillary zone electrophoresis (CZE), to ICP-MS, is discussed. Comparisons have been made with detection limits obtained by using the flame ionization detector. The conventional technique of liquid chromatography for the speciation of vanadium, chromium and nickel is also discussed.

Nasal septum lesions caused by chromium exposure among chromium electroplating workers

A chromium electroplating worker, suffering from epistaxis during work, was found to have nasal septum perforation. To determine the etiology and prevalence of nasal septum lesions, we conducted a survey of seven chromium electroplating factories and examined 79 workers. Forty workers from three aluminum electroplating factories were also enrolled as the reference group. Subjects were thoroughly examined by an otolaryngologist and each of them provided a blood and urine sample. A questionnaire interview regarding symptoms of the upper respiratory tract, past medical history, life style, and work history was also conducted. Air chromium concentrations were measured by taking area samples for 4-6 hours. Based on field observation and chromium measurements, we divided chromium electroplating into three different exposure zones: workers directly dealing with electroplating tanks (n = 31), other process workers (n = 29), and office workers and drivers (n = 19). Among the 79 chromium electroplating workers, there were 16 cases of nasal septum perforation, and 42 with either scar formation or ulceration; 10 chromium electroplating workers developed skin ulcers after performing chrome plating. No workers from aluminum electroplating factories had any nasal septum or skin abnormalities. There was a consistent trend between the degree of chromium exposure and the signs and symptoms related to the nose, throat, and skin. Immediate improvement of occupational hygiene is warranted.

[Experimental bases of the use of a specialized product Arman in chromium intoxication]

A trial has been performed of anti-intoxication properties of the stuff Arman containing fruit and vegetable fibers in Cr toxicosis. It is demonstrated that 30-day Arman feeding resulted in rats in Cr content fall in the blood and rise in the urine and feces. The protective effect of Arman was confirmed by changes in the body mass, morphological investigations of the liver tissue and by general condition of the animals. The product exhibited antioxidant properties. It is suggested that a marked antitoxic effect of Arman in Cr intoxication may be due to accelerated elimination of Cr compounds from the animal body.

Nickel, cobalt and chromium in consumer products: a role in allergic contact dermatitis?

In spite of the improved awareness of the potential for nickel, cobalt and chromium to cause skin allergy, the incidence of sensitization to them is generally on the increase, especially for nickel. We review data from the literature and industry on transition metal contamination of consumer products and assess the hazard to man. Consumer products are defined as personal care items and detergent/cleaning products used regularly in domestic work. The analytical data demonstrate that consumer products are a relatively minor source of contact with nickel, cobalt or chromium. The traces found in consumer products will not be the primary cause of sensitization to these metals: levels will be too low and exposure too brief. A person sensitized to these metals has many other more significant sources of daily contact such as earrings, jewelry and metal objects. It is therefore necessary to focus on decreasing the high exposure to these transition metals from other sources rather than on possible trace amounts found in consumer products. Current good manufacturing practice ensures that trace nickel, cobalt and chromium concentrations in consumer products are less than 5 ppm of each metal. It is recommended that this be accepted as a standard for maximum concentrations and that the target should be to achieve concentrations as low as 1 ppm.

[Chromium: physiologic role and implications in human pathology]

Reported values for total body stores of chromium vary between 0.4 mg and 6 mg. Chromium stores may be higher in neonates than in adults, relative to body size, whereas tissular chromium may be depleted in the elderly. The recommended daily allowance for chromium is 50 to 200 micrograms/day but actual needs are poorly known. Digestive absorption is better for organic chromium, which is part of the "glucose tolerance factor" (GTF), than for inorganic chromium. Furthermore, chromium (VI) is better absorbed than chromium (III). In the body, chromium (VI) is rapidly reduced to chromium (III) by a number of metabolic pathways. Absorbed chromium binds to proteins, mainly to transferrin which exhibits a high affinity for chromium (III). Most absorbed chromium is eliminated through the kidneys. Renal excretion occurs according to a two or more-compartment model. Current methods used to assay chromium, i.e., atomic absorption spectrometry using a graphite furnace or neutron activation, are sufficiently sensitive and specific to evaluate chromium levels in blood, urine or hair. However, none of these levels accurately reflects chromium body stores. Chromium is part of the GTF molecule. This factor has no effect per se but may facilitate binding of insulin to insulin receptors and amplify the effects of insulin on carbohydrate and lipid metabolism. Chromium deficiency may play a role in a development of some forms of adult diabetes mellitus and of arteriosclerosis. Partial chromium deficiencies seem to be common, especially in individuals with high intakes of refined foods. Acute chromium poisoning is usually due to an excess of chromium (VI) and is sometimes seen in the chromium industry.(ABSTRACT TRUNCATED AT 250 WORDS)