Chromium VI

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Toxicology

Human Health

Unlike Cr(III) which passes through cell walls with a very low efficiency, Cr(VI ) readily crosses cell membranes and can produce a number of potentially mutagenic effects upon reduction to Cr(III). Cr(III) within a cell membrane is not necessarily benign. Chromium VI can cause adverse health affects through three exposure routes: inhalation, ingestion, and dermal contact.

Inhalation of Cr(VI) containing compounds can produce severe health affects that differ according to the solubility of the compound. For example a chromic acid aerosol can severely damage nasal mucosa and cause perforation of the nasal septum, while exposure to an insoluble compound might impact the lower respiratory tract. In industrial workers, inhalation of Cr(VI) has been shown to produce asthma, with intermediate to chronic duration exposure causing an increased risk of death due to noncancer respiratory disease. Acute dermal allergic reactions from inhalation of Cr(VI) also have been observed in chromium sensitive individuals. Finally, occupational exposure to Cr(VI) compounds has been directly linked to an increased risk of developing respiratory system cancers (ATSDR 2000).

Ingested Cr(VI) is readily reduced to Cr(III) in the gastrointestinal tract. Absorption of Cr(VI) occurs much more efficiently than Cr(III), but it is estimated that 5% or less of ingested Cr(VI) is actually absorbed (Grevatt 1998). Minimal epidemiology data are available to evaluate the effects of ingesting Cr(VI) compounds at levels typically found in the environment. Grevatt (1998) states that an increase in body burden from ingestion of chromium has been observed in animal studies. An increase in organ body burden would also be expected in human ingestion of chromium. The effects of this increase in body burden in humans are not well defined. As with inhalation of chromium by sensitive individuals, ingestion may also cause allergic reactions including dermatitis (ATSDR 2000).

With dermal exposures, chromate and dichromate compounds can be very caustic and are capable of causing burns. In concentrations lower than required for burns, Cr(VI) compounds can cause contact dermatitis and skin ulcers.

For Further Information

Chromium (VI) (CASRN 18540-29-9)
U.S. EPA, Integrated Risk Information System (IRIS), Sep 1998.

Chromium Compounds: Hazard Summary
U.S. EPA, Technology Transfer Network, Air Toxics Website.

Interaction Profile for Arsenic, Cadmium, Chromium and Lead
Agency for Toxic Substances and Disease Registry, 2004.

The primary purpose of this Interaction Profile for arsenic, cadmium, chromium and lead is to evaluate data on the toxicology of the mixture as a whole and the joint toxic action of the chemicals in the mixture in order to recommend approaches for assessing the potential health hazard.

NTP Study of the Hexavalent Chromium Compound Sodium Dichromate Dihydrate
U.S. Department of Health and Human Services, National Toxicology Program.

This page contains a collection of toxicity evaluations concerning Cr(VI).

A Probabilistic Exposure Assessment for Children Who Contact CCA-Treated Playsets, Using the Stochastic Human Exposure and Dose Simulation Model for the Wood Preservative Exposure Scenario (SHEDS-Wood)
V.G. Zartarian, J. Xue, H. Ozkaynak, W. Dang, G. Glen, L. Smith, and C. Stallings.
EPA 600-X-05-009, 315 pp, 2005.

Reflections on Hexavalent Chromium: Health Hazards of an Industrial Heavyweight
Cheryl Pellerin, Susan M. Booker.
Environmental Health Perspectives, 108(9):A402-A407, Sep 2000

Report on Carcinogens, Eleventh Edition
U.S. Department of Health and Human Services, Public Health Service, National Toxicology Program, Chromium Hexavalent Compounds 4 pp, 2005.

Toxicological Profile for Chromium
Agency for Toxic Substances and Disease Registry (ATSDR), Sep 2000

This toxicological profile contains a public health statement followed by chapters on health effects; chemical and physical information; production, import, use, and disposal; potential for human exposure; analytical methods; regulations and advisories; and references.

Toxicological Review of Hexavalent Chromium (CAS No. 18540-29-9) in Support of Summary Information on the Integrated Risk Information System (IRIS)
Peter C. Grevatt.
U.S. Environmental Protection Agency, 77 pp, Aug 1998
Contact: Peter C. Grevatt, grevatt.peter@epa.gov

Ecological Impacts

Hexavalent chromium compounds, when present, are more likely to be in solution than in sediments (except for insoluble salts such as lead and zinc). This makes them directly available to aquatic life. In general, invertebrate species are more sensitive to acute exposures to Cr(VI) than fish species (EPA 1988). Chromium may bioaccumulate in algae, other aquatic vegetation, and invertebrates, but it does not biomagnify. Chronic exposure to chromium inhibits growth in duckweed and algae, reduces fecundity and survival of benthic invertebrates, and reduces growth of freshwater fingerlings (EPA Region V).

For Further Information

Chromium Hazards to Fish, Wildlife, and Invertebrates: a Synoptic Review
Eisler, Ronald, U.S. Fish and Wildlife Service, Patuxent Wildlife Research Center, Laurel, MD.
U.S. Fish and Wildlife Service, Biological Report 85(1.6), Contaminant Hazard Reviews #6, Jan 1986
Contact: Ronald Eisler, Ronald_Eisler@usgs.gov

Chromium Toxicity Effects on Microorganisms and Treatment Processes
Prabha Krishan, Texas A&M Univ., College Station, TX.
NTIS: DE00761432, 73 pp, 1997

This paper reviews the toxic effects of chromium on microorganisms and on some of the treatment processes, such as activated sludge, anaerobic digestion, and denitrification.

Chromium VI (Hexavalent Chromium Ion, CAS number 18540-29-9)
In Environmental Contaminants Encyclopedia, R.J. Irwin, M. VanMouwerik, L. Stevens, M.D.
Seese, and W. Basham (compilers).
National Park Service, Water Resources Division, Fort Collins, CO. 43 pp., 1997
Contact: Roy Irwin, roy_irwin@nps.gov

Chromium: Water Quality Standards Criteria Summaries: A Compilation of State/Federal Criteria
USEPA, EPA/440/5-88/026

Ecological Risk Assessment: Information on the Toxic Effects of Various Chemicals and Groups of Chemicals Toxicity Profiles
USEPA Region V.

Methods/Indicators for Determining When Metals Are the Cause of Biological Impairments of Rivers and Streams: Species Sensitivity Distributions and Chronic Exposure-Response Relationships from Laboratory Data
P. Shaw-Allen and G.W. Suter II, U.S. EPA, Cincinnati, OH.
Report No: EPA 600-X-05-027, pp, July 2005

Provides information on the effects of the common aquatic metal contaminants (cadmium, chromium, copper, lead, mercury, nickel, and zinc, plus arsenic and selenium) on laboratory animals for use in the strength-of-evidence step of the stressor identification process to help determine whether metals contribute to biological impairments.

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Last updated on Monday, April 7, 2008