CHROMATE

CHROMIUM (+)

CHROMIUM (CR+6)

CHROMIUM (CR6+)

CHROMIUM (CR6+) ION

CHROMIUM (Cr(sup6+))

CHROMIUM [HEXAVALENT]

CHROMIUM HEXAVALENT ION

CHROMIUM, ION (CR6+)

CHROMIUM, ION (CR6+)(8CI,9CI)

CHROMIUM, ION (Cr(sup 6+)) (8CI,9CI)

CHROMIUM (VI)

CHROMIUM (VI) COMPOUNDS

NCI-C04273

18540-29-9(Chromium (VI))

GB6262000

Cr

Editor's Note: An ERG guide with information appropriate to this material does not exist.

Hexavalent chromium is the oxidation state of chromium most commonly used in commercial applications. It is capable of forming colorful and insoluble salts. Chromium trioxide, potassium dichromate, and sodium dichromate are examples of compounds that contain Cr(+6) (ILO, 1998).

Chromates of weak bases are used as pigments. Compounds containing Cr(+6) are used in making lead chromes, molybdate oranges, chromium oxide green, and zinc chromate. They are also used for preserving wood, inhibiting corrosion, and in colorful glass and glaze (ILO, 1998).

Hexavalent chromium compounds are used to make pigments, in metal finishing processes, and in wood preservatives (ATSDR, 1993).

Materials containing Cr (VI) are used to make graphic art supplies, paper matches, tanning solutions, and lithography solutions (NIOSH , 1975).

Most chromium compounds are brightly colored. Pigments account for nearly 33 % of their use. Chromium is used as a component of inorganic pigments, especially in coloring for floor covering products, paper, cement, and asphalt roofing. It is used to produce an emerald color in glass. It is also used in the textile industry for dyeing, silk treating, printing, and moth proofing wool (Clayton & Clayton, 1994a; Lewis, 1998; HSDB, 2001; Zenz, 1994).

Cr (VI) is one of three valence states of chromium (Sittig, 1991a).

The following compounds are commonly made with Chromium (VI): ammonium dichromate, chromium (VI) oxide, potassium chromate, potassium dichromate, sodium chromate, and sodium bichromate (NIOSH , 1975).

Chromium (VI) is always hydrated and takes the form of a monochromate, bichromate, or polychromate ion (NIOSH , 1975).

Barium chromate, calcium chromate, lead chromate, strontium chromate, zinc chromate, and sintered chromium trioxide are examples of hexavalent chromium compounds that are insoluble in water. These compounds are generally believed to be carcinogenic based on epidemiologic investigations and animal studies (Hathaway et al, 1996).

Hexavalent chromium compounds, incorrectly called chromates (unless they exist as CrO3(-2) ions), usually have a yellow pigment. Compounds included are chromium trioxide (CrO3; chromium VI oxide), the anhydride of chromic acid, chromates, dichromates, and polychromates. These are generally the most toxic chromium compounds, particularly the water-insoluble forms. Certain compounds are considered human carcinogens (Clayton & Clayton, 1994a; ACGIH, 1991a).

Water-soluble hexavalent chromium compounds include chromic acid, its anhydride, and monochromates and dichromates of sodium, potassium, ammonium, lithium, cesium, and rubidium (ACGIH, 1991a).

Water-insoluble hexavalent chromium compounds include zinc chromate, calcium chromate, lead chromate, barium chromate, strontium chromate, and sintered chromium trioxide (ACGIH, 1991a).

Welders are exposed to hexavalent chromium particles (Clayton & Clayton, 1994a).

Exposure to CCA (chromate-copper-arsenate) treated wood, through construction or burning in a home heating stove has produced dermal, respiratory, gastrointestinal, hematologic, and neurologic signs and symptoms. Elevated tissue arsenic levels were documented, but the role of chromium in these illnesses was not determined (Peters et al, 1986, 1983, 1984).

In Europe, household bleaches may contain chromate for coloring in quantities sufficient to produce contact dermatitis (Burrows, 1983). In the USA, household bleaches contain approximately 0.1 ppm, which probably does not represent a risk factor for sensitization (Hostynek & Maibach, 1988).

In France, match heads may contain potassium dichromate. Forty such match heads contain approximately 5 mg of potassium dichromate (Picaud et al, 1991).

When chromium is roasted with soda ash and lime in air, it is oxidized to form soluble and insoluble chromates (Cr +6) (ACGIH, 1996).

Hexavalent chromium is present in cement. Sources of Cr (VI) in cement may include volcanic rock, abrasion of refractory lining in kilns, and steel balls and other tools used for grinding and crushing raw materials for cement (NIOSH , 1998). Portland cement contains an average of 2.9 mg/kg of soluble hexavalent chromium (ATSDR, 1993).

Fly ash from coal-fired power plants may contain Cr (VI) (ATSDR, 1993).

Hexavalent chromium is believed to make up 100% of the chromium emissions from cooling towers. Total cooling tower emissions of Cr (VI) in 1990 were estimated to be as high as 290.51 metric tons/year by the EPA. Chrome plating emissions are approximately 100% Cr (VI) and were estimated by the EPA to be 700 metric tons/year in 1990 (ATSDR, 1993).

Chromium (VI) can be found in cement, detergents, glue, and chromite ore (NIOSH , 1975).

Chromium (III) in chromite is oxidized by oxygen at high temperatures to yield Chromium (VI). Water-soluble Cr (VI) is made when soda ash is added to molten chromite ore.

Stainless steel welding fumes contain hexavalent chromium (ACGIH, 1991a).

Electroplating operations produce a Cr (VI) mist that is water-soluble (ACGIH, 1991a).

FIRST AID

INHALATION EXPOSURE

DERMAL EXPOSURE

EYE EXPOSURE

ORAL EXPOSURE

A high incidence of lung cancer has been reported for workers with heavy exposure to hexavalent chromium compounds. The lung cancer tends to develop 15 or more years after the initial exposure. Exposure in excess of 50 mg Cr(+6)/m(3) air are most closely associated with respiratory cancers (ILO, 1998).

A 44 year old man died upon ingesting a liquid containing chromium trioxide, which equated to a dose of 4.1 mg Cr (VI)/kg/day. A 14 year old boy died after ingesting 1.5 g of potassium dichromate, which equated to a dose of 7.5 mg Cr (VI)/kg/day. A 17 year old boy ingested a fatal 5 g of potassium dichromate, which equated to a dose of 29 mg Cr (VI)/kg/day (ATSDR, 1993).

Of 24 Norwegian pigment manufacturing workers exposed to 0.19-0.43 mg Cr (VI)/m(3), three developed lung cancer (NIOSH , 1975).

More than 60% of workers at an Ohio chromate factory died of lung cancer in the 1930's. The workers were exposed to 0.01 to 0.15 mg water-soluble Cr (VI)/m(3) and 0.1 to 0.58 mg insoluble Cr (VI)/m(3) (Clayton & Clayton, 1994).

Death due to multi-organ system failure occurred in a 35-year-old female 12 hours after ingesting 50 milliliters of pure chromic acid (25 grams hexavalent chromium) (Loubieres et al, 1999).

Workers in a porcelain enamel curing operation developed skin problems, including skin ulcerations, as a result of defective curing oven coils. Open flames from the defective coils allowed Cr (VI) to get on curing equipment in the oven. At the same time, the open flames made equipment edges sharp. Employees who handled the equipment cut their hands which allowed Cr (VI) to get under their skin. Environmental samples for Cr (VI) in the area showed a range of values between 0.1 and 4.4 mcg/mg (NIOSH, 1990).

Portland cement containing hexavalent chromium causes 5 to 15 percent of workers who come into contact with it to develop allergic contact dermatitis. The number of cases of allergic contact dermatitis declined by 80 percent when chromium levels in cement were reduced to less than 2 ppm (Center to Protect Workers' Rights, 1998).

Inhalation of Cr (VI) concentrations greater than 2 mcg/m(3) can cause nasal irritation, including runny nose, itching, sneezing, nosebleeds, ulcers, and perforation of the nasal septum (ATSDR, 1993).

In a case study of 9 men working at a chrome plating facility for half a month to a year, 7 of the men developed nasal septum ulceration. Symptoms included epistaxis, nasal itching and soreness, and rhinorrhea. Exposure concentrations were measured to be 0.09 to 0.73 mg Cr (VI)/m(3) (ATSDR, 1993).

Workers exposed to >= 0.1 mg Cr (VI)/m(3) for less than one year developed coughing, sneezing, nasal irritation, expectoration, rhinorrhea, nose bleeds, and nasal septum ulceration and perforation (ATSDR, 1993).

An U.S. electroplating facility was evaluated by NIOSH in 1975. Workers exposed to average concentrations of 0.004 mg Cr (VI)/m(3) for an average of 7.5 years developed epistaxis, nasal ulceration, and rhinitis. Of 11 employees, 4 had nasal septum perforation (ATSDR, 1993).

Czechoslovakian electroplating workers exposed to 0.414 mg Cr (VI)/m(3) developed chronic tonsillitis, chronic pharyngitis, atrophy of the left larynx, and papilloma (ATSDR, 1993).

Of 65 surveys of Italian chromate production workers exposed to > = 0.01 mg Cr (VI)/m(3), 10 had developed duodenal ulcers and 6 had colitis (ATSDR, 1993).

Electroplating workers exposed to 0.008 mg Cr (VI)/m(3) had an increased number of chromosomal aberrations and sister chromatid exchanges. These findings were confounded by worker exposure to nickel (ATSDR, 1993).

Chromium (VI) platers exposed to approximately 60 mcg Cr (VI)/m(3) for 6 to 7 hours per day for 1 week to 2 months, developed inflamed mucosa and nosebleeds (NIOSH , 1975).

Authors of a study in the Soviet Union determined that exposure to 10-24 mcg Cr (VI)/m(3) caused reports of sharp nasal irritation by a group of ten volunteers. The same group of volunteers was unable to perceive airborne levels of 1.5 mcg Cr (VI)/m(3) (NIOSH , 1975).

A 1955 study of alkali chromate workers exposed to 55-75 mcg Cr (VI)/m(3) over the course of 3 years identified only one worker with nasal septum ulceration, a few with inflamed conjuctiva and laryngeal mucosa, a few with chronic bronchitis, one with nasal septum cancer, and one with lung cancer (NIOSH , 1975).

Workers at an anodizing plant had estimated exposures of 210-600 mcg Cr (VI)/m(3) when working within 200 feet of the anodizing tanks. The workers developed nasal ulcers. Installation of a ventilation system over the tanks decreased chromium (VI) air concentrations to 45-50 mcg/m(3). However, the physical condition of the workers did not improve (NIOSH , 1975).

Chromium-plating operator exposed to 9.1 mcg Cr (VI)/m(3) suffered from nasal mucosal irritation and nasal septum perforation. These finding were confounded by poor worker hygiene practices, which including hand-nose contact (NIOSH , 1975).

Workers exposed to 0.11 to 0.15 mg Cr (VI)/m(3) developed nasal septum ulcers, irritation of the conjuctiva, larynx, and pharynx, and asthmatic bronchitis (Hathaway, 1996).

Ingestion of 10 milliliters of a hexavalent chromium compound by a child resulted in gastroenteritis, circulatory insufficiency, acute renal and hepatic failure, and coma. The patient survived following n-acetylcysteine treatment, aggressive supportive care, and hemodialysis (Ulmeanu et al, 1997).

Nasal irritation has occurred in facilities where the mean water-soluble airborne hexavalent chromium concentrations were 0.068 mg/m(3). Airborne levels as low as 0.06 mg/m(3) of CHROMIUM TRIOXIDE (CrO3; CHROMIUM VI OXIDE) have also been shown to cause nasal irritation (ACGIH, 1991).

A concentration of 350 to 500 ppm of hexavalent chromium in soil should be sufficiently low to protect exposed persons from chromium-induced allergic contact dermatitis in chromate-sensitive individuals (Paustenbach et al, 1992).

Cancer risk attributed to hexavalent chromium in soil is estimated at no more that 1 in 1,000,000 at a concentration of 100 ppm (Paustenbach et al, 1992).

Females are more sensitive to the lethal effects of chromium (VI) based on acute dermal, inhalation, and oral animal studies (ATSDR, 1993; (Clayton & Clayton, 1994).

CARCINOGENICITY RATINGS

ACGIH (American Conference of Governmental Industrial Hygienists, 2010): Not Listed

EPA (U.S. Environmental Protection Agency, 2011): A ; Listed as: Chromium(VI)

EPA (U.S. Environmental Protection Agency, 2011): D ; Listed as: Chromium(VI)

IARC (International Agency for Research on Cancer (IARC), 2016; International Agency for Research on Cancer, 2015; IARC Working Group on the Evaluation of Carcinogenic Risks to Humans, 2010; IARC Working Group on the Evaluation of Carcinogenic Risks to Humans, 2010a; IARC Working Group on the Evaluation of Carcinogenic Risks to Humans, 2008; IARC Working Group on the Evaluation of Carcinogenic Risks to Humans, 2007; IARC Working Group on the Evaluation of Carcinogenic Risks to Humans, 2006; IARC, 2004): Not Listed

NIOSH (National Institute for Occupational Safety and Health, 2007): Not Listed

MAK (DFG, 2002): Category 2 ; Listed as: Chromium(VI) compounds (as dusts/aerosols), with the exception of those practically insoluble in water such as lead chromate, barium chromate (but zinc chromate Section III Category 1)

NTP (U.S. Department of Health and Human Services, Public Health Service, National Toxicology Project ): Not Listed

Oral:

Inhalation:

Drinking Water:

Oral:

Inhalation:

Drinking Water:

References: (ATSDR, 1993)

References: (ATSDR, 1993)

Not Listed

Not Listed

Not Listed

Listed as: Chromium (VI) compounds; see 1910.1026

Table Z-1 for Chromium (VI) compounds; see 1910.1026:

Not Listed

Not Listed

Not Listed

Not Listed

Editor's Note: The D, F, and K series waste numbers and Appendix VIII to Part 261 -- Hazardous Constituents were not included. Please refer to 40 CFR Part 261.

Not Listed

Not Listed

Not Listed

Not Listed

Not Listed

Store away from strong oxidizers such as bromine, chlorine, and fluorine. Ignition sources should be eliminated from areas where chromium compounds are handled, stored, or used (Sittig, 1991).

Specific recommendations and test data for this chemical were not found in the available manufacturers' product literature. A complete list of consulted manufacturers and references is presented below.

Editor's Note: An ERG guide with information appropriate to this material does not exist.

Not Listed

Chromic acid and chromates attack cloth, coating, leather, metals, plastics, and rubber. This attack can result in spontaneous ignition (NIOSH, 1978).

Not Listed

Chromic acid and chromates do not have any hazardous decomposition products (NIOSH, 1978).

Not Listed

Not Listed

Not Listed

Not Listed

Editor's Note: An ERG guide with information appropriate to this material does not exist.

Editor's Note: An ERG guide with information appropriate to this material does not exist.

When a chromate or chromic acid spill occurs, the spill area should be evacuated except for those workers wearing appropriate personal protective equipment. The area should be ventilated. Place spilled material in sealed containers. Spilled liquids should be absorbed with vermiculite, soil, or dry sand and placed in sealed containers (NIOSH, 1978).

Editor's Note: An ERG guide with information appropriate to this material does not exist.

Wastes from plating operations, tanneries, chemical plants, and cooling water blow-down may be recovered and recycled (Sittig, 1991).

Chromates and chromic acid may be placed in sealed containers and disposed of in a sanitary landfill (NIOSH, 1978).

Waste management activities associated with material disposition are unique to individual situations. Proper waste characterization and decisions regarding waste management should be coordinated with the appropriate local, state, or federal authorities to ensure compliance with all applicable rules and regulations.

Hexavalent chromium wastes may be reduced to Cr (III) and then precipitated to a hydrous oxide using lime or caustic soda (ATSDR, 1993).

pH affects the adsorption of hexavalent chromium onto activated carbon. Hexavalent chromium was adsorbed and reduced to the trivalent form at pH less than 6 by the catalytic action of the carbon, but was not adsorbed at all at pH greater than or equal to 12. The adsorption capacity was increased by raising the temperature from 25 to 40 degrees C (Ramos et al, 1994).

Iron has shown promise in subsurface chromate remediation. The process involves converting hexavalent chromate ions (CrO4)(-2) to the less mobile and less toxic trivalent form using iron as the reducing agent. Impure, partially oxidized iron has been shown to be the most effective form of iron in the reaction. Aluminosilicate aquifer materials appear to help maintain these reactions. A reactive barrier within the aquifer is constructed to enhance the reaction (Powell et al, 1995).

Hematite (iron oxide) was able to remove 97% of chromium (VI) from aqueous solution at 40 degrees C and pH 2.7, when the initial chromium concentration was 19.23 mcmol/L and the hematite was 40 g/L (Singh et al, 1993).

Hexavalent chromium is often treated by first reducing it to the trivalent form using a reducing agent such as sulfur dioxide, sodium bisulfite, sodium metabisulfite, or ferrous sulfate applied at pH between 2 and 3. Sulfur dioxide is widely used because of the smaller amount required to treat chromium wastes than with other reducing agents. Once the waste stream has been pretreated, techniques for precipitating the trivalent form of chromium may be used (Freeman, 1989).

Precipitation of hexavalent chromium may be accomplished directly without the intermediate reduction to the trivalent form by reacting it with a metal sulfide such as ferrous sulfide (FeS). One disadvantage of this method is the potential for liberating toxic hydrogen sulfide gas (Freeman, 1989).

Constructed wetlands containing large amounts of organic matter have been shown to remove hexavalent chromium from acidic waste streams in a laboratory setting. This process holds promise as a cost-effective primary or secondary treatment for chromium-containing waste streams generated by the electroplating and metal finishing industries (Makos & Hrncir, 1995).

The bacterium, Escherichia coli ATCC-33456, quantitatively reduced hexavalent chromium into trivalent chromium. The reduction proceeded under both aerobic and anaerobic conditions and was not inhibited by cyanide or azide (Shen & Wang, 1993).

Washings with hot water or a dilute alkali solution (0.1M NaOH) were found to remove 95 to 99% of hexavalent chromium from a mixture of ore processing residue and soil. This treatment method could be used as a first step to quickly and inexpensively remove the more mobile hexavalent form of chromium from contaminated sites. Remaining trivalent chromium could be left for later cleanup or concurrently removed with a hot concentrated acid solution (Ososkov & Bozzelli, 1994).

Chromium is cleared from the atmosphere in less than 10 days by fallout and precipitation (ATSDR, 1993).

Hexavalent chromium is reduced to Cr (III) in the atmosphere by vanadium (ATSDR, 1993).

SURFACE WATER

TERRESTRIAL

OTHER

Bioaccumulates in freshwater fish (Lewis, 1998).

Hexavalent chromium can bioaccumulate in trout at levels as low as 0.001 ppm (OHM/TADS , 2001).

AQUATIC

Chromium is not biomagnified in the terrestrial food chain (ATSDR, 1993).

Oyster, blue mussel, soft shell clam: 86-192 (ATSDR, 1993)

Salmo gairdneri (rainbow trout): approximately 1 (hexavalent chromium) (ATSDR, 1993)

IL50 - (MULTIPLE) EURASION WATERMILFOIL: 1.9 ppm - root weight affected

IL50 - (MULTIPLE) EURASION WATERMILFOIL: 2.6 ppm - stem weight affected

IL50 - (MULTIPLE) EURASION WATERMILFOIL: 8.0 ppm - length affected

IL50 - (MULTIPLE) EURASION WATERMILFOIL: 9.5 ppm - stem length affected

The following hexavalent chromium compounds are soluble in water: chromic acid, ammonium dichromate, potassium chromate, potassium dichromate, sodium chromate, and sodium dichromate dihydrate (ATSDR, 1993; (Clayton & Clayton, 1994).

Sodium dichromate, ammonium chromate, lithium chromate, lithium dichromate, cesium chromate, cesium dichromate, rubidium chromate, and rubidium dichromate are water-soluble hexavalent chromium compounds (Clayton & Clayton, 1994).

Calcium chromate and strontium chromate are less soluble in water. Lead chromate and zinc chromate are essentially insoluble in cold water (ATSDR, 1993).

Odorless (NIOSH, 1978).