Chrome VI, also known as hexavalent chromium, is the second most stable oxidation state of chromium. Rarely occurring naturally, most chrome VI compounds are manufactured by industrial processes.
Chrome VI compounds can be both, soluble or insoluble, and they are mostly lemon-yellow to orange to dark red. They are typically solid (i.e. crystalline, granular, or powdery) although one compound (chromyl chloride) is a dark red liquid that decomposes into chromate ions and hydrochloric acid in water.
Why is chrome VI a hazardous substance?
Chrome VI compounds are very toxic for human beings.
The most common health problem resulting from its exposure involves the respiratory tract, including symptoms and diseases such as irritation of the lining of the nose, runny nose, and breathing problems such as asthma, cough, shortness of breath, and wheezing.
Exposure to this substance via inhalation and/or ingestion can cause lung cancer and damage to the kidneys, liver, skin and eyes.
Moreover, dermal exposure to chrome VI compounds can cause skin irritation, ulceration, sensitization, and allergic contact dermatitis.
Many workers in a variety of occupations are potentially exposed to chrome VI, especially in jobs involving welding and other types of “hot work” on stainless steel and other metals that contain chrome, use of pigments, spray paints and coatings, and operating chrome plating baths In the European Union (EU), the estimated number of Cr(VI)-exposed workers in 2012 was approximately 786,000, with the largest numbers exposed to welding.
For last, it should be noted that breathing contaminated workplace air is the main source in occupational settings, but for the general population, exposure to Chrome VI occurs primarily by ingestion of contaminated soil, food, and water, but also through inhalation of ambient air.
Where can Chrome VI be found?
Chrome VI is a chemical element that can be found naturally in the environment, in rocks, animals, plants and soil. Although, its presence usually comes from manufacturing processes and manufactured consumer products. After release from the manufacture, use, and disposal of chrome-based products, and during the manufacturing process, chrome can be found in air, soil, and water.
Chrome compounds are used widely in applications that include:
- Pigment for textile dyes
- Paints
- Inks
- Plastics
- Corrosion inhibitors
- Wood preservatives
- Metal finishing and chrome plating
- Leather tanning (ammonium dichromate).
Additionally, chrome VI may be present as an impurity in Portland cement, and it can be generated and given off during casting, welding, and cutting operations (for example, of stainless steel), even if it was not originally present in its hexavalent state.
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This article can be found in the 2021 edition of the document. Find the full publication here:
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