Chromium

52

51.94050

231-157-5

0R0008Q3JB

0029

1759|3089

DTXSID3031022

C370

Steel-gray, lustrous metal; body-centered cubic structure|Blue-white to steel-gray, lustrous, brittle, hard solid|Hard, brittle, semigray metal

8112210000

0

0.00000

Silver-gray powder

7.14 g/cm³

1900 °C

2642 °C

50 °F

Insoluble in water.

Storage temperature: no restrictions.

0 mmHg (approx)

Not reported-Rat LD50: 27.5 mg/kg

Non-combustible; toxic chromium-containing fumes are produced in the fire;

Powder will explode spontaneously in air. ... May ignite or react violently with bromine pentafluoride.

Odorless

Bivalent chromium compounds are basic; trivalent chromium compounds are amphoteric; hexavalent chromium compounds are acidic

Enthalpy of fusion: 403.9 J/g at the melting pt|Under strongly oxidizing conditions, may be converted to hexavalent state & occur as chromate anions|Electronegativity (Pauling Scale): 1.6; orbital electrons: (Ar)3d5-4s1; abundance (% of earth's crust): 2X10-2|Chromium is a mixture of four stable isotopes with mass numbers 50 (4.31%), 52 (83.76%), 53 (9.55%) and 54 (2.38%). Thermal neutron capture cross sections are 17, 0.8, 18 and 0.38 barns, respectively.|For more Other Experimental Properties (Complete) data for CHROMIUM, ELEMENTAL (9 total), please visit the HSDB record page.

May be pyrophoric, as dust. Insoluble in water.

Metals, Elemental and Powder, Active

Pyrophoric

CHROMIUM reacts violently with NH4NO3, N2O2, Li, NO, KClO3, SO2 (NTP, 1992). Metal dusts when suspended in atmospheres of carbon dioxide may ignite and explode.

Noncombustible Solid in bulk form, but finely divided dust burns rapidly if heated in a flame.

Dust explosion possible if in powder or granular form, mixed with air.

The silver soldered stainless steel wire corroded more than the cobalt-chromium type, & released more nickel & chromium than did the cobalt-chromium wires.

81.7 kcal/mol (at the boiling point)

III

4.1

UN 2924 3/PG 2

3

11-20/21/22-34-40-23-67-36

16-26-36/37/39-45-36/37-27

GB4200000

F,C,Xn,Xi

Low temperature, ventilated, and dry in the warehouse; store it separately from food materials; avoid dust

Stable. Incompatible with carbonates, strong bases, mineral acids, lithium, sulfur dioxide, strong acids.

P201, P202, P260, P261, P264, P270, P271, P272, P280, P281, P285, P302+P352, P304+P340, P304+P341, P305+P351+P338, P308+P313, P309+P311, P312, P321, P333+P313, P337+P313, P342+P311, P363, P403+P233, P405, P501

H410

Generators of waste (equal to or greater than 100 kg/mo) containing this contaminant, EPA hazardous waste number D007, must conform with USEPA regulations in storage, transportation, treatment and disposal of waste. /Chromium/|Precipitation is the preferred treatment process for removing toxic heavy metals from electroplating waters. Precipitation processes include hydroxide, lime and/or sulfide treatment. Chemical reduction is used to treat complex metals such as nickel, copper, hexavalent chromium waste, soluble lead, silver, metal containing cyanide, and mercury. Adsorption has shown potential for treating and polishing aqueous metal bearing wastes. Activated carbon, activated alumina, and iron filings are all applicable adsorbents. Alkaline chlorination and incineration are effective cyanide destruction treatments. Evaporation, ion-exchange, reverse osmosis, electrodialysis, and electrolytic recovery are waste reduction and recovery techniques applicable to metal bearing hazardous streams.|Waste disposal method: Chromium metal or insoluble chromium salts may be disposed of in sealed containers in a secured sanitary landfill. /Chromium metal and insoluble chromium salts/|Product: Offer surplus and non-recyclable solutions to a licensed disposal company. Contaminated packaging: Dispose of as unused product.|For more Disposal Methods (Complete) data for CHROMIUM, ELEMENTAL (10 total), please visit the HSDB record page.

Molten lithium at 180 °C attacks vanadium, beryllium, or chromium severely.|Reacts with dilute HCl /hydrochloric acid/, H2SO4 /sulfuric acid/ ... .|Powder will explode spontaneously in air. Ignites & is potentially explosive in atmospheres of carbon dioxide. Violent or explosive reaction when heated with ammonium nitrate. May ignite or react violently with bromine pentafluoride. Incandescent reaction with nitrogen oxide or sulfur dioxide.|Chromium is attacked vigorously by fused potassium chlorate, producing vivid incandescence. Pyrophoric chromium unites with sulfur dioxide with incandescence. Pyrophoric chromium unites with nitric oxide with incandescence.|For more Hazardous Reactivities and Incompatibilities (Complete) data for CHROMIUM, ELEMENTAL (7 total), please visit the HSDB record page.

ATSDR; Toxicological Profile for Chromium (September, 2012)[ATSDR; Toxicological Profile for Chromium (September, 2012); Available from, as of October, 27, 2015: http://www.atsdr.cdc.gov/toxprofiles/tp7.pdf]

Excerpt from ERG Guide 154 [Substances - Toxic and/or Corrosive (Non-Combustible)]: Non-combustible, substance itself does not burn but may decompose upon heating to produce corrosive and/or toxic fumes. Some are oxidizers and may ignite combustibles (wood, paper, oil, clothing, etc.). Contact with metals may evolve flammable hydrogen gas. Containers may explode when heated. For electric vehicles or equipment, ERG Guide 147 (lithium ion batteries) or ERG Guide 138 (sodium batteries) should also be consulted. (ERG, 2016)|Combustible under specific conditions.|Flammable - 3rd degree

|Danger|H317 (39.12%): May cause an allergic skin reaction [Warning Sensitization, Skin]|P261, P264, P272, P273, P280, P285, P302+P352, P304+P341, P305+P351+P338, P321, P333+P313, P337+P313, P342+P311, P363, P391, and P501|Aggregated GHS information provided by 2284 companies from 19 notifications to the ECHA C&L Inventory. Each notification may be associated with multiple companies.|Warning|H400: Very toxic to aquatic life [Warning Hazardous to the aquatic environment, acute hazard]|P273, P391, and P501|H317: May cause an allergic skin reaction [Warning Sensitization, Skin]|P201, P202, P260, P261, P264, P270, P271, P272, P280, P281, P285, P302+P352, P304+P340, P304+P341, P305+P351+P338, P308+P313, P309+P311, P312, P321, P333+P313, P337+P313, P342+P311, P363, P403+P233, P405, and P501|P261, P264, P271, P272, P280, P285, P302+P352, P304+P340, P304+P341, P305+P351+P338, P312, P321, P333+P313, P337+P313, P342+P311, P363, P403+P233, P405, and P501

Excerpt from ERG Guide 154 [Substances - Toxic and/or Corrosive (Non-Combustible)]: As an immediate precautionary measure, isolate spill or leak area in all directions for at least 50 meters (150 feet) for liquids and at least 25 meters (75 feet) for solids. SPILL: Increase, in the downwind direction, as necessary, the isolation distance shown above. FIRE: If tank, rail car or tank truck is involved in a fire, ISOLATE for 800 meters (1/2 mile) in all directions; also, consider initial evacuation for 800 meters (1/2 mile) in all directions. (ERG, 2016)

SMALL SPILLS AND LEAKAGE: If you spill this chemical, dampen the solid spill material with 5% ammonium hydroxide, then transfer the dampened material to a suitable container. Use absorbent paper dampened with 5% ammonium hydroxide to pick up any remaining material. Your contaminated clothing and the absorbent paper should be sealed in a vapor-tight plastic bag for eventual disposal. Wash all contaminated surfaces with 5% ammonium hydroxide followed by washing with a strong soap and water solution. Do not reenter the contaminated area until the Safety Officer (or other responsible person) has verified that the area has been properly cleaned. STORAGE PRECAUTIONS: You should store this material in a refrigerator. (NTP, 1992)

Skin: No recommendation is made specifying the need for personal protective equipment for the body. Eyes: No recommendation is made specifying the need for eye protection. Wash skin: No recommendation is made specifying the need for washing the substance from the skin (either immediately or at the end of the work shift). Remove: No recommendation is made specifying the need for removing clothing that becomes wet or contaminated. Change: No recommendation is made specifying the need for the worker to change clothing after the work shift. (NIOSH, 2016)|Gloves or rubber coats protect against chrome ulceration of the skin.|Respirator Recommendations: Up to 2.5 mg/cu m:[Table#2392]|Respirator Recommendations: Up to 5 mg/cu m:[Table#2393]|Respirator Recommendations: Up to 12.5 mg/cu m:[Table#2394]|For more Personal Protective Equipment (PPE) (Complete) data for CHROMIUM, ELEMENTAL (12 total), please visit the HSDB record page.|(See protection codes)

... When finely divided burns rapidly if heated in flame.

When /dust/ is suspended in carbon dioxide atmospheres ... /it is/ ignitable and explosive ... .|Powder will explode spontaneously in air. ... May ignite or react violently with bromine pentafluoride.

Use water spray, alcohol-resistant foam, dry chemical or carbon dioxide. Wear self-contained breathing apparatus for firefighting if necessary.|Respiratory protection from chromium metal and insoluble chromium salts while fighting fires: self-contained breathing apparatus with a full facepiece operated in pressure-demand or other positive pressure mode. /Chromium metal and insoluble chromium salts/

Chromium oxides

Collect spilled material in the most convenient & safe manner & deposit in sealed containers for reclamation or for disposal in a secured sanitary landfill. Liq containing chromium metal or insoluble chromium salts should be absorbed in vermiculite, dry sand, earth, or similar material.|If chromium metal or insoluble chromium salts are spilled, the following steps should be taken: 1. Remove all ignition sources where metallic chromium has been spilled. 2. Ventilate area of spill. 3. Collect spilled material in the most convenient and safe manner and deposit in sealed containers for reclamation or for disposal in a secured sanitary landfill. Liquid containing chromium metal or insoluble chromium salts should be absorbed in vermiculite, dry sand, earth, or a similar material. /Chromium metal and insoluble chromium salts/|ACCIDENTAL RELEASE MEASURES; Personal precautions, protective equipment and emergency procedures: Avoid dust formation. Avoid breathing vapors, mist or gas. Ensure adequate ventilation. Evacuate personnel to safe areas. Environmental precautions: Prevent further leakage or spillage if safe to do so. Do not let product enter drains. Discharge into the environment must be avoided. Methods and materials for containment and cleaning up: Pick up and arrange disposal without creating dust. Sweep up and shovel. Keep in suitable, closed containers for disposal.|If chromium metal or insoluble chromium salts are spilled, the following steps should be taken: 1. Remove all ignition sources where metallic chromium has been spilled. 2. Ventilate area of spill. 3) Collect spilled material in the most convenient and safe manner and deposit in sealed containers for reclamation or for disposal in a secured sanitary landfill. Liquid containing chromium metal or insoluble chromium salts should be absorbed in vermiculite, dry sand, earth, or a similar material. /Chromium metal and insoluble chromium salts/

Daily washing of the inside of the nose combined with covering the nasal septum with zinc or barium ointment should be sufficient to avoid ulcerations and perforation of the septum.|SRP: Local exhaust ventilation should be applied wherever there is an incidence of point source emissions or dispersion of regulated contaminants in the work area. Ventilation control of the contaminant as close to its point of generation is both the most economical and safest method to minimize personnel exposure to airborne contaminants. Ensure that the local ventilation moves the contaminant away from the worker.|Provide appropriate exhaust ventilation at places where dust is formed.|Gloves must be inspected prior to use. Use proper glove removal technique (without touching glove's outer surface) to avoid skin contact with this product. Dispose of contaminated gloves after use in accordance with applicable laws and good laboratory practices. Wash and dry hands.|For more Preventive Measures (Complete) data for CHROMIUM, ELEMENTAL (9 total), please visit the HSDB record page.

Chromium aerosols ... caused ... irritation to the upper respiratory tract. /SRP: dusts or particulates/|Chromium causes severe nasal irritation ... .

Permissible Exposure Limit: Table Z-1 8-hr Time Weighted Avg: 1 mg/cu m. /Chromium metal and insoluble salts, as Cr/|Permissible Exposure Limit: Table Z-1 8-hr Time Weighted Avg: 0.5 mg/cu m. /Chromium(II) compounds, as Cr/|Permissible Exposure Limit: Table Z-1 8-hr Time Weighted Avg: 0.5 mg/cu m. /Chromium(III) compounds, as Cr/|Permissible Exposure Limit: Table Z-2 Acceptable Ceiling Concentration: 1 mg/10 cu m. /Chromic acid and chromates (as CrO3)/

Recommended Exposure Limit: 8-hour Time-Weighted Average: 0.5 mg Cr/cu m. /Chromium metal, chromium(II) and chromium(III) compounds/|Recommended Exposure Limit: 8-hour Time-Weighted Average: 0.0002 mg Cr(VI)/cu m. NIOSH considers all Cr(VI) compounds (including chromic acid, tert-butyl chromate, zinc chromate, and chromyl chloride) to be potential occupational carcinogens. /All hexavalent chromium (Cr(VI) compounds/|NIOSH usually recommends that occupational exposures to carcinogens be limited to the lowest feasible concentration. /Chromic acid and chromates/

Personal protection: particulate filter respirator adapted to the airborne concentration of the substance. Sweep spilled substance into covered containers. If appropriate, moisten first to prevent dusting.

A harmful concentration of airborne particles can be reached quickly when dispersed.

May cause mechanical irritation to the eyes and respiratory tract.

If powder: NO open flames Closed system, dust explosion-proof electrical equipment and lighting. Prevent deposition of dust.

PREVENT DISPERSION OF DUST!

Use local exhaust or breathing protection.

Protective gloves.

Wear safety goggles.

... Substances for which a Federal Register notice has been published that included consideration of the serious health effects, including cancer, from ambient air exposure to the substance. Chromium is included on this list. /Chromium/|Listed as a hazardous air pollutant (HAP) generally known or suspected to cause serious health problems. The Clean Air Act, as amended in 1990, directs EPA to set standards requiring major sources to sharply reduce routine emissions of toxic pollutants. EPA is required to establish and phase in specific performance based standards for all air emission sources that emit one or more of the listed pollutants. Chromium compounds is included on this list. /Chromium compounds/

Chromium is a naturally occurring element found in rocks, animals, plants, soil, and in volcanic dust and gases. Chromium is present in the environment in several different forms. The most common forms are chromium(0), chromium(III), and chromium(VI). No taste or odor is associated with chromium compounds. Chromium(III) occurs naturally in the environment and is an essential nutrient. Chromium(VI) and chromium(0) are generally produced by industrial processes.The metal chromium, which is the chromium(0) form, is used for making steel. Chromium(VI) and chromium(III) are used for chrome plating, dyes and pigments, leather tanning, and wood preserving.|Chromium occurs in the environment primarily in two valence states, trivalent chromium (Cr III) and hexavalent chromium (Cr VI). Exposure may occur from natural or industrial sources of chromium. Chromium III is much less toxic than chromium (VI). The respiratory tract is also the major target organ for chromium (III) toxicity, similar to chromium (VI). Chromium (III) is an essential element in humans. The body can detoxify some amount of chromium (VI) to chromium (III). The respiratory tract is the major target organ for chromium (VI) toxicity, for acute (short-term) and chronic (long-term) inhalation exposures. Shortness of breath, coughing, and wheezing were reported from a case of acute exposure to chromium (VI), while perforations and ulcerations of the septum, bronchitis, decreased pulmonary function, pneumonia, and other respiratory effects have been noted from chronic exposure. Human studies have clearly established that inhaled chromium (VI) is a human carcinogen, resulting in an increased risk of lung cancer. Animal studies have shown chromium (VI) to cause lung tumors via inhalation exposure.

D007; A waste containing chromium may or may not be characterized as a hazardous waste following testing by the Toxicity Characteristic Leaching Procedure as prescribed by the Resource Conservation and Recovery Act (RCRA) regulations.

Persons in charge of vessels or facilities are required to notify the National Response Center (NRC) immediately, when there is a release of this designated hazardous substance, in an amount equal to or greater than its reportable quantity of 5000 lb or 2270 kg. The toll free number of the NRC is (800) 424-8802. The rule for determining when notification is required is stated in 40 CFR 302.4 (section IV. D.3.b). ... No reporting of releases of this hazardous substance is required if the diameter of the pieces of the solid metal released is larger than 100 micrometers (0.004 inches).

D007; A solid waste containing chromium may or may not become characterized as a hazardous waste when subjected to the Toxicity Characteristic Leaching Procedure listed in 40 CFR 261.24, and if so characterized, must be managed as a hazardous waste. /Chromium/

highly toxic

Oral LD50 for Cr (VI) is 135 - 175 mg/kg in mouse and 46 - 113 mg/kg in rat. Oral LD50 for Cr (III) in rat is >2000 mg/kg. LD50 of chromium (III) oxide in rats is reported to be > 5g/kg. Other LD50 values reported for rats include: 3.5 g/kg (CI 3.19-3.79 g/kg) for chromium sulphate; 11.3 g/kg for chromium (III) acetate; 3.3 g/kg for chromium nitrate; and 1.5 g/kg for chromium nitrate nonahydrate. Acute overdose of chromium is rare and seriously detrimental effects of hexavalent chromium are primarily the result of chronic low-level exposure. In case of overdose with minimal toxicity following acute ingestion, treatment should be symptomatic and supportive. There is no known antidote for chromium toxicity. Hexavalent chromium is a Class A carcinogen by the inhalation route of exposure and Class D by the oral route. The oral lethal dose in humans has been estimated to be 1-3 g of Cr (VI); oral toxicity most likely involves gastrointestinal bleeding rather than systemic toxicity. Chronic exposure may cause damage to the following organs: kidneys, lungs, liver, upper respiratory tract [MSDS]. Soluble chromium VI compounds are human carcinogens. Hexavalent chromium compounds were mutagenic in bacteria assays and caused chromosome aberrations in mammalian cells. There have been associations of increased frequencies of chromosome aberrations in lymphocytes from chromate production workers. In human cells _in vitro_, Cr (VI) caused chromosomal aberrations, sister chromatid exchanges and oxidative DNA damage.|IDENTIFICATION AND USE: Chromium elemental (Cr) is a steel-gray, lustrous metal. It is used in maufacturing of chrome-steel or chrome-nickel-steel alloys (stainless steel), nonferrous alloys, heat resistant bricks for refractory furnaces. This helps greatly increase strength, hardness and resistance of metals to abrasion, corrosion and oxidation. It is also used for chrome plating of other metals; leather tanning; as pigment and mordant and as a wood preservative. In medicine and laboratory research (51)Cr is used as a diagnostic aid. HUMAN EXPOSURE AND TOXICITY: Human exposure to Cr is increasing due to its use in Metal-on-metal (MOM) total hip arthroplasties. Metal-on-metal arthroplasty may lead to elevated blood Cr and cobalt (Co) levels. Cases of hypersensitivity to Cr and Co have been reported in such patients. Also both circulating-free-DNA and 8-hydroxydeoxyguanosine showed a tendency to increase in male patients. However, CoCr hip implants appear to be nongenotoxic. In electric welders exposed to Cr, a significant correlation was found between the frequency of sister chromatid exchanges and individual DNA strand breakage versus the concentration of Cr in the urine. ANIMAL STUDIES: Rats (25 total) were given 6 weekly iv injections of 0.18 mL of a 0.05% suspension of chromium powder; round cell sarcomas were found in 4 rats; 1 rat had hemangioma; 2 rats had papillary adenomas of the lung, and one rat showed extensive squamous cell carcinomatous changes. Metallic Cr was assayed for the ability to induce cell transformation (anchorage-independent growth) in Syrian hamster fibroblasts. Although chromium particles were phagocytized by cells, no significant increase in the number of cell foci growing in soft agar was observed. In male rats exposed to Cr fumes generated from powders of Cr metal by plasma flame sprayer developed significant increases in the frequencies of sister chromatid exchange and of chromosomal aberrations observed in peripheral blood lymphocytes, whereas chromosomal aberration frequencies in bone-marrow cells were unchanged. ECOTOXICITY STUDIES: Cr was toxic to naiad mollusks at 12.4 ppm. The greatest Cr toxicity risk to plants is posed in acidic sandy soil with low organic content.

Humans and other organisms are exposed to multi-chemical mixtures including commonly found carcinogens such as polycyclic aromatic hydrocarbons (PAHs) and heavy metal/loids. The joint effects of these chemicals as beyond the binary mixtures have not been well characterized. In this study, we evaluated the combined genotoxicity of mixtures of PAHs and heavy metal and metalloids containing benzo(a)pyrene (B[a]P), naphthalene (Nap), phenanthrene (Phe), pyrene (Pyr), arsenic (As), cadmium (Cd) and chromium (Cr) using in vitro micronucleus (MN) test in HepG2 cells. The induction of aryl hydrocarbon receptor (AhR) by single and mixed PAHs was also measured. The results indicated that individual and mixed Nap, Phe and Pyr did not induce significant MN frequencies. PAHs mixture containing B[a]P and B[a]P alone caused significant but similar level of MN frequencies. The same pattern was found in their AhR induction. Individual metal and metalloids induced significant cytostasis and MN formation of which Cd was found the most potent inducer. Mixture of metal and metalloids caused higher frequency of MN suggesting a possible additive effect among metal and metalloids. In addition, binary mixture of metal/loids and B[a]P, namely As/B[a]P, Cd/B[a]P and Cr/B[a]P, increased MN formation. Mixture of Cd and B[a]P induced the highest level of MN. Exposure of cells to the mixture containing B[a]P and Cd/Cr/As at lower concentration (0.25 uM) resulted in significant MN frequency, the level of which was equal to that by Cd/B[a]P at 1.0 uM. The results of the study suggested that an additive effect may exist between PAHs and heavy metal/loids in a compound- and concentration-dependent manner. The compounds with highest potencies of genotoxicity in the mixture seem dominant as driving sources in the final combined genotoxicity of PAHs and heavy metal and metalloids.|... Rats ... given 1 intratracheal intubation of 10 mg powder chromium alone or ... with ... methylcholanthrene & killed at ... intervals up to 12 wk. Squamous-cell carcinomas of lung developed ... in 7/12 rats given 5 mg methylcholanthrene+chromium 3/12 given 1 mg methylcholanthrene+chromium ... 3/7 given 5 mg methylcholanthrene ... 1/8 given 1 mg methylcholanthrene & in 0/12 given chromium alone. /No controls reported/

In the blood, 95% of chromium (III) is bound to large molecular mass proteins, such as transferrin, while a small proportion associates with low molecular mass oligopeptides. Serum chromium is bound to transferrin in the beta globulin fraction.

Chromium is found in nature only in the combined state and not as the element. ...

According to the 2012 TSCA Inventory Update Reporting data, 69 reporting facilities estimate the number of persons reasonably likely to be exposed during the manufacturing, processing, or use of chromium (7440-47-3) may be as low as <10 workers up to the range of 1000-9999 workers per plant; the data may be greatly underestimated due to confidential business information (CBI) or unknown values(1).|NIOSH (NOES Survey 1981-1983) has statistically estimated that 386,142 workers (10,433 of these are female) were potentially exposed to chromium, elemental in the US(1).

Indicated for use as a supplement to intravenous solutions given for total parenteral nutrition (TPN), to maintain chromium serum levels and to prevent depletion of endogenous stores and subsequent deficiency symptoms.|FDA Label

Trivalent chromium is part of glucose tolerance factor, an essential activator of insulin-mediated reactions. Chromium helps to maintain normal glucose metabolism and peripheral nerve function. Chromium increases insulin binding to cells, increases insulin receptor density and activates insulin receptor kinase leading to enhanced insulin sensitivity. In chromium deficiency, intravenous administration of chromium resulted in normalization of the glucose tolerance curve from the diabetic-like curve typical of chromium deficiency.

A group of chemical elements that are needed in minute quantities for the proper growth, development, and physiology of an organism. (From McGraw-Hill Dictionary of Scientific and Technical Terms, 4th ed) (See all compounds classified as Trace Elements.)

Chromium compounds are both absorbed by the lung and the gastrointestinal tract. Oral absorption of chromium compounds in humans can range between 0.5% and 10%, with the hexavalent (VI) chromium more easily absorbed than the trivalent (III) form. Absorption of chromium from the intestinal tract is low, ranging from less than 0.4% to 2.5% of the amount consumed. Vitamin C and the vitamin B niacin is reported to enhance chromium absorption. Most hexavalent Cr (VI) undergoes partial intragastric reduction to Cr (III) upon absorption, which is an action mainly mediated by sulfhydryl groups of amino acids. Cr (VI) readily penetrates cell membranes and chromium can be found in both erythrocytes and plasma after gastrointestinal absorption of Cr (IV). In comparison, the presence of chromium is limited to the plasma as Cr (III) displays poor cell membrane penetration. Once transported through the cell membrane, Cr (VI) is rapidly reduced to Cr (III), which subsequently binds to macromolecules or conjugate with proteins. Cr (III) may be bound to transferrin or other plasma proteins, or as complexes, such as glucose tolerance factor (GTF).|Absorbed chromium is excreted mainly in the urine, accounting for 80% of total excretion of chromium; small amounts are lost in hair, perspiration and bile. Chromium is excreted primarily in the urine by glomerular filtration or bound to a low molecular-weight organic transporter.|Absorbed chromium is distributed to all tissues of the body and its distribution in the body depends on the species, age, and chemical form. Circulating Cr (III) following oral or parenteral administration of different compounds can be taken up by tissues and accumulates in the liver, kidney, spleen, soft tissue, and bone.|Excretion of chromium is via the kidneys ranges from 3 to 50 μg/day. The 24-hour urinary excretion rates for normal human subjects are reported to be 0.22 μg/day.|The objective of the Part II analysis was to evaluate animal and in vitro toxicology studies of CoCr particles with respect to their physicochemistry and dose relevance to metal-on-metal (MoM) implant patients as derived from Part I. In the various toxicology studies, physicochemical characteristics were infrequently considered and administered doses were orders of magnitude higher than what occurs in patients. Co was consistently shown to rapidly release from CoCr particles for distribution and elimination from the body. CoCr micron sized particles appear more biopersistent in vivo resulting in inflammatory responses that are not seen with similar mass concentrations of nanoparticles. We conclude, that in an attempt to obtain data for a complete risk assessment, future studies need to focus on physicochemical characteristics of nano and micron sized particles and on doses and dose metrics relevant to those generated in patients or in properly conducted hip simulator studies. /CoCr particles/|The kinetics of metal ions release from orthodontic appliances in in vitro, in in vivo on pigs, and in vivo trials on patients (where hair samples were taken) was discussed. We have evaluated (by means of ICP-OES and ISO 17025) and compared the mass of Cr and Ni ions released. Not all the metal ions released from the appliance were transferred to hair tissue. The transfer factor was expressed as coefficient omega and evaluated as: omegaCr(patients) 33.0%, omegaCr(pigs) 17.2%, omegaNi(patients) 49.8%, omegaNi(pigs) 0.553%. The kinetics was described by a power function. Coefficient omega was used to combine the models: the in vitro and in vivo on animals on the one hand and the in vitro and in vivo on human on the other, which enabled the extrapolation of in vitro and translation of the results into in vivo conditions. The dose of metal ions released during orthodontic treatment was estimated.

The metabolism of Cr (VI) involves reduction by small molecules and enzyme systems to generate Cr (III) and reactive intermediates. During this process, free radicals can be generated, which is thought to induce damage of cellular components and cause toxicity of chromium. The metabolites bind to cellular constituents.

The elimination half-life of hexavalent chromium is 15 to 41 hours.

Chromium is an essential nutrient involved in the metabolism of glucose, insulin and blood lipids. Its role in potentiating insulin signalling cascades has been implicated in several studies. Chromium upregulates insulin-stimulated insulin signal transduction via affecting effector molecules downstream of the insulin receptor (IR). IR-mediated signalling pathway involves phoshorylation of multiple intracellular domains and protein kinases, and downstream effector molecules. Upon activation by ligands, intracellular β-subunit of IR autophosphorylates and activates tyrosine kinase domain of the IR, followed by activation and phosphorylation of regulatory proteins and downstream signalling effectors including phosphatidylinositol 2-kinase (PI3K). PI3K activates further downstream reaction cascades to activate protein kinase B (Akt) to ultimately promote translocation of glucose transporter-4 (Glut4)-vesicles from the cytoplasm to the cell surface and regulate glucose uptake. Chromium enhances the kinase activity of insulin receptor β and increases the activity of downstream effectors, pI3-kinase and Akt. Under insulin-resistant conditions, chromium also promotes GLUT-4 transporter translocation that is independent of activity of IR, IRS-1, PI3-kinase, or Akt; chromium mediates cholesterol efflux from the membranes via increasing fluidity of the membrane by decreasing the membrane cholesterol and upregulation of sterol regulatory element-binding protein. As a result, intracellular GLUT-4 transporters are stimulated to translocate from intracellular to the plasma membrane, leading to enhanced glucose uptake in muscle cells. Chromium attenuates the activity of PTP-1B _in vitro,_ which is a negative regulator of insulin signaling. It also alleviates ER stress that is observed to be elevated the suppression of insulin signaling. ER stress is thought to activate c-Jun N-terminal kinase (JNK), which subsequently induces serine phosphorylation of IRS and aberration of insulin signalling. Transient upregulation of AMPK by chromium also leads to increased glucose uptake.|While the toxicity of metals and metalloids, like arsenic, cadmium, mercury, lead and chromium, is undisputed, the underlying molecular mechanisms are not entirely clear. General consensus holds that proteins are the prime targets; heavy metals interfere with the physiological activity of specific, particularly susceptible proteins, either by forming a complex with functional side chain groups or by displacing essential metal ions in metalloproteins. Recent studies have revealed an additional mode of metal action targeted at proteins in a non-native state; certain heavy metals and metalloids have been found to inhibit the in vitro refolding of chemically denatured proteins, to interfere with protein folding in vivo and to cause aggregation of nascent proteins in living cells. Apparently, unfolded proteins with motile backbone and side chains are considerably more prone to engage in stable, pluridentate metal complexes than native proteins with their well-defined 3D structure. By interfering with the folding process, heavy metal ions and metalloids profoundly affect protein homeostasis and cell viability. This review describes how heavy metals impede protein folding and promote protein aggregation, how cells regulate quality control systems to protect themselves from metal toxicity and how metals might contribute to protein misfolding disorders.

Exposure Routes: inhalation, ingestion, skin and/or eye contact Symptoms: Irritation eyes, skin; lung fibrosis (histologic) Target Organs: Eyes, skin, respiratory system (NIOSH, 2016)

EYES: First check the victim for contact lenses and remove if present. Flush victim's eyes with water or normal saline solution for 20 to 30 minutes while simultaneously calling a hospital or poison control center. Do not put any ointments, oils, or medication in the victim's eyes without specific instructions from a physician. IMMEDIATELY transport the victim after flushing eyes to a hospital even if no symptoms (such as redness or irritation) develop. SKIN: IMMEDIATELY flood affected skin with water while removing and isolating all contaminated clothing. Gently wash all affected skin areas thoroughly with soap and water. If symptoms such as redness or irritation develop, IMMEDIATELY call a physician and be prepared to transport the victim to a hospital for treatment. INHALATION: IMMEDIATELY leave the contaminated area; take deep breaths of fresh air. IMMEDIATELY call a physician and be prepared to transport the victim to a hospital even if no symptoms (such as wheezing, coughing, shortness of breath, or burning in the mouth, throat, or chest) develop. Provide proper respiratory protection to rescuers entering an unknown atmosphere. Whenever possible, Self-Contained Breathing Apparatus (SCBA) should be used; if not available, use a level of protection greater than or equal to that advised under Protective Clothing. INGESTION: Some heavy metals are VERY TOXIC POISONS, especially if their salts are very soluble in water (e.g., lead, chromium, mercury, bismuth, osmium, and arsenic). IMMEDIATELY call a hospital or poison control center and locate activated charcoal, egg whites, or milk in case the medical advisor recommends administering one of them. Also locate Ipecac syrup or a glass of salt water in case the medical advisor recommends inducing vomiting. Usually, this is NOT RECOMMENDED outside of a physician's care. If advice from a physician is not readily available and the victim is conscious and not convulsing, give the victim a glass of activated charcoal slurry in water or, if this is not available, a glass of milk, or beaten egg whites and IMMEDIATELY transport victim to a hospital. If the victim is convulsing or unconscious, do not give anything by mouth, assure that the victim's airway is open and lay the victim on his/her side with the head lower than the body. DO NOT INDUCE VOMITING. IMMEDIATELY transport the victim to a hospital. OTHER: Since this chemical is a known or suspected carcinogen you should contact a physician for advice regarding the possible long term health effects and potential recommendation for medical monitoring. Recommendations from the physician will depend upon the specific compound, its chemical, physical and toxicity properties, the exposure level, length of exposure, and the route of exposure. (NTP, 1992)|(See procedures)

Fresh air, rest.

Remove contaminated clothes. Rinse skin with plenty of water or shower.

First rinse with plenty of water for several minutes (remove contact lenses if easily possible), then refer for medical attention.

Immediate first aid: Ensure that adequate decontamination has been carried out. If patient is not breathing, start artificial respiration, preferably with a demand-valve resuscitator, bag-valve-mask device, or pocket mask, as trained. Perform CPR as necessary. Immediately flush contaminated eyes with gently flowing water. Do not induce vomiting. If vomiting occurs, lean patient forward or place on left side (head-down position, if possible) to maintain an open airway and prevent aspiration. Keep patient quiet and maintain normal body temperature. Obtain medical attention. /Inorganic acids and related compounds/|Basic treatment: Establish a patent airway (oropharyngeal or nasopharyngeal airway, if needed). Suction if necessary. Watch for signs of respiratory insufficiency and assist respirations if needed. Administer oxygen by nonrebreather mask at 10 to 15 L/min. Monitor for pulmonary edema and treat if necessary ... . Monitor for shock and treat if necessary ... . For eye contamination, flush eyes immediately with water. Irrigate each eye continuously with 0.9% saline (NS) during transport ... . Do not use emetics. Activated charcoal is not effective. For ingestion, rinse mouth and administer 5 mL/kg up to 200 mL of water for dilution if the patient can swallow, has a strong gag reflex, and does not drool ... . Do not attempt to neutralize because of exothermic reaction. Cover skin burns with dry, sterile dressings after decontamination ... . /Inorganic acids and related compounds/|Advanced treatment: Consider orotracheal or nasotracheal intubation for airway control in the patient who is unconscious, has severe pulmonary edema, or is in severe respiratory distress. Early intubation, at the first sign of upper airway obstruction, may be necessary. Positive-pressure ventilation techniques with a bag valve mask device may be beneficial. Consider drug therapy for pulmonary edema ... . Consider administering a beta agonist such as albuterol for severe bronchospasm ... . Monitor cardiac rhythm and treat arrhythmias as necessary ... . Start IV administration of D5W /SRP: "To keep open", minimal flow rate/. Use 0.9% saline (NS) or lactated Ringer's(LR) if signs of hypovolemia are present. For hypotension with signs of hypovolemia, administer fluid cautiously. Consider vasopressors if patient is hypotensive with a normal fluid volume. Watch for signs of fluid overload ... . Use proparacaine hydrochloride to assist eye irrigation ... . /Inorganic acids and related compounds/|Emergency and supportive measures. 1. Inhalation. Give supplemental oxygen. Treat wheezing and monitor the victim closely for delayed-onset noncardiogenic pulmonary edema. Delays in the onset of pulmonary edema of up to 72 hours have been reported after inhalation of concentrated solutions of chromic acid. 2. Ingestion. a. Diluted immediately with water. treat hemorrhagic gastroenteritis with aggressive fluid and blood replacement. Consider early endoscopy to assess the extent of esophageal or gastric injury. b. Treat hemoglobinuria resulting from hemolysis with alkaline diuresis as far rhabdomyolysis. Treat methemoglobinemia if it occurs. /Chromium/|For more Antidote and Emergency Treatment (Complete) data for CHROMIUM, ELEMENTAL (7 total), please visit the HSDB record page.

/HUMAN EXPOSURE STUDIES/ Metal-on-metal (MOM) total hip arthroplasties were reintroduced because of the problems with osteolysis and aseptic loosening related to polyethylene wear of early metal-on-polyethylene (MOP) arthroplasties. The volumetric wear rate has been greatly reduced with MOM arthroplasties; however, because of nano-size wear particles, the absolute number has been greatly increased. Thus, a source of metal ion exposure with the potential to sensitize patients is present. We hypothesized that higher amounts of wear particles result in increased release of metal ions and ultimately lead to an increased incidence of metal allergy. 52 hips in 52 patients (median age 60 (51-64) years, 30 women) were randomized to either a MOM hip resurfacing system (ReCap) or a standard MOP total hip arthoplasty (Mallory Head/Exeter). Spot urine samples were collected preoperatively, postoperatively, after 3 months, and after 1, 2, and 5 years and tested with inductively coupled plasma-sector field mass spectrometry. After 5 years, hypersensitivity to metals was evaluated by patch testing and lymphocyte transformation assay. In addition, the patients answered a questionnaire about hypersensitivity. A statistically significant 10- to 20-fold increase in urinary levels of cobalt and chromium was observed throughout the entire follow-up in the MOM group. The prevalence of metal allergy was similar between groups. While we observed significantly increased levels of metal ions in the urine during the entire follow-up period, no difference in prevalence of metal allergy was observed in the MOM group. However, the effect of long-term metal exposure remains uncertain.|/CASE REPORTS/ Metal-on-metal arthroplasty may lead to elevated blood chromium (Cr) and cobalt (Co) levels (>7 ug/L). Since carcinogenic, mutagenic, and teratogenic effects have been suggested, there is concern of pregnancy hazards for women with this condition. The 34-year-old patient has had a unilateral hip replacement for seven years. Before her pregnancy high Cr (47 ug/L) and Co (103 ug/L) blood concentrations were measured, but she did not develop any symptoms. A male infant was delivered after 41 weeks with first degree hypospadias. His levels were increased at 3 weeks of age: 14 ug/L (Cr) and 20 ug/L (Co), but decreased by 9 weeks to 6.7 ug/L (Cr) and 10.0 ug/L (Co). Maternal levels at delivery were 25 ug/L (Cr) and 51 ug/L (Co). The child was fully breast-fed and developed normally. An association between hypospadias and Cr/Co has to be considered speculative. The otherwise favorable outcome of this case may be reassuring for pregnant and breast-feeding patients with metal-on-metal hip replacements.|/CASE REPORTS/ A 75-year-old woman who had undergone hybrid metal-on-metal hip resurfacing 8 years earlier underwent revision arthroplasty because of hip, groin and lateral thigh pain. The main differential was aseptic loosening; however, serum cobalt and chromium levels were normal. Multiple imaging modalities revealed a periprosthetic, cystic soft tissue mass adjacent to the proximal femur. A large 'pseudotumor' with proximal femoral invasion was found at revision arthroplasty. We report the first finding of a 'pseudotumor' invading the proximal femur with normal metal ions following metal on metal hip resurfacing.|/CASE REPORTS/ We report a series of three patients who underwent uncemented total hip arthroplasty with a modular titanium-molybdenum-zirconium-iron stem and a cobalt-chrome-molybdenum head on an ultra-high molecular weight highly cross-linked polyethylene liner bearing. All three cases subsequently developed pain and adverse reaction to metal debris, leading to revision of the implants within thirty-six months. They were subsequently found to have hypersensitivity to cobalt or chromium. However where tested, blood metal ion levels were within ...guideline limits. Corrosion was noted at the taper-trunnion junction. It is possible, that the multi alloy head-neck combination may lead to corrosion.|For more Human Toxicity Excerpts (Complete) data for CHROMIUM, ELEMENTAL (16 total), please visit the HSDB record page.

Chromium

inhalation, ingestion, skin and/or eye contact

irritation eyes, skin; lung fibrosis (histologic)

Cough.

Redness.

Immunological (Immune System), Renal (Urinary System or Kidneys), Respiratory (From the Nose to the Lungs)|Eyes, skin, respiratory system

STAINLESS & HEAT RESISTING STEELS, 71.4%; FULL ALLOY STEEL, 15.2%; HIGH STRENGTH, LOW ALLOY & ELECTRIC STEELS, 3.1%; SUPERALLOYS, 2.8%; CAST IRONS, 2.6%; CARBON STEEL, 2.4%; OTHER, 2.5% (1982, CHROMIUM & CHROMIUM ALLOY USE)|Stainless and heat resisting steel, 76%; full alloy steel, 11%; super alloys, 4% and other alloys, 9% (1986) /Consumption of chromium ferroalloys, metal, and other chromium containing materials by end use/|Ferrous alloys, mainly stainless steels, account for most of the consumption.|Chromium: Consumption: Reported

Chromium metal is available in the USA as electrolytic chromium (99.5% Cr), aluminothermic chromium (98.5% Cr) & ductile chromium (99.99% Cr).|Available forms: (1) chromium metal as lumps, granules, or powder; (2) high or low-carbon ferrochromium; (3) single crystals, high-purity crystals, or powder run 99.97% pure.

Computer and electronic product manufacturing|Chromium: ACTIVE

Chemical Classes -> Inorganic substances|Hazardous Air Pollutants (HAPs)|Fire Hazards -> Flammable - 3rd degree