Environmental Medicine Integrating a Missing Element into Medical Education (1995) / Chapter Skim
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Case Study 11: Chromium Toxicity
Case Study 11: Chromium Toxicity
Pages 291-311
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From page 291... ...
is an essential nutrient, which can be toxic in large doses. Ed The toxicity of chromium compounds depends on the oxidation state of the metal.
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From page 292... ...
Physical examination reveals an alert white male with skin lesions on the exposed areas of the forearms and hands; edema of the hands is present. The dermal lesions include dermatitis and small circular areas with shallow ulcerated centers.
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From page 293... ...
Refractory uses of chromium include magnesitechrome firebrick for metallurgical furnace linings and granularchromite for various other heat-resistant applications. Chromium exists in a series of oxidation statesfrom -2 valence to +6; the most important stable states are O {elemental metal)
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From page 294... ...
Less significant environmental sources of chromium include road dust contaminated by emissions of chromium-based catalytic converters or erosion products of asbestos brake linings, cement dust, tobacco smoke, andfoodstuffs. CigarettescontainO.24to 14.6 milligram chromiurnAcilogram, but nether the amount of chromium inhaled nor the chemical form is known.
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From page 295... ...
O Risk assessment Is currently underway for residents living on landfill derived from chromium-containing solid wastes. Workers in industries using chromium, especially stainless steel welding, chromate production, chrome plating, and chrome pigment industries, where exposure is primarily to Or (Vl)
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From page 296... ...
Occupational exposure generally occurs through inhalation and dermal contact, while the general population is exposed most often by the oral route through chromium content in soil, food, and water. Rates of chromium uptake from the gastrointestinal tract are relatively low and depend on a number of factors, including valence state {with Cr EVIL more readily absorbed than Cr [111~)
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From page 297... ...
as a protein complex is by bone marrow, lungs, lymph nodes, spleen, kidney, and liver. Autopsies reveal chromium levels in the lungs are consistently h~herthan levels in other organs.
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From page 298... ...
In one patient receiving total parenteral nutrition, a peripheral neuropathy was corrected after chromium supplementation. Major factors governing the toxicity of chromium compounds are oxidation state and solubility.
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From page 299... ...
permissible exposure level in the workplace for chromates and chromic acid is 100 ~g/m3 over an 8-hour period.) The period of exposure for workers experiencing nasal mucosal ulceration varied from 5 months to 10 years.
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From page 300... ...
Although glomen~lar injury has been noted in chromium workers, the predominant renal injury is tubular, with low doses acting specifically on the proximal convoluted tubules. Low-dose, chronic chromium exposure typically results only in transient renal effects.
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From page 301... ...
All pathologic cell types have occurred in chromium-induced lung cancers; however, small cell and poorly differentiated cancers predominate. Findings of some epidemiologic studies and animal experiments suggest chromium is also associated with nonrespiratory cancers, but the evidence is insufficient to consider the nonrespiratory cancers to be of a causal nature.
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From page 302... ...
In patients with known chronic chromium exposure, the physical examination should include evaluation of the respiratory system (if inhalation is involved) , kidneys, liver, and skin.
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From page 303... ...
O In occupational settings, the most commonly reported effects of chronic chromium exposure are contact dermatitis, and Irritation and ulcoratlon of the nasal mucosa. O Less common are reports of hopatic and renal damage and pulmonary effects.
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From page 304... ...
For example, use of stainless steel utensils to collect tissue samples may raise tissue chromium levels, as will stainless steel grinding and homogenizing equipment. Some plastic containers contain significant amounts of leachable chromium; therefore, specially prepared acid-washed containers should be obtained from the laboratory.
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From page 305... ...
Hair ornail analysis is of little use in evaluating an individual patient since it is impossible to distinguish chromium bound within the hair during protein synthesis from chromium deposKed on the hair from dust, water, or other external sources. Populations with no known chromium exposure reportedly have hair levels ranging from 50 to 1000 ppm chromium.
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From page 306... ...
Weeping dermatitis can be treated with 1% aluminum acetate wet dressings, and chrome ulcers can be treated with topical ascorbic acid. If the exposure has been lengthy (i.e., 2 to 3 years)
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From page 307... ...
mandated an 8-hourworkday, 40-hourworkweek permissible exposure limit (PEL) of 100 119 CrO3tm3 for chromic acid and chromates (ceiling)
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From page 308... ...
1000 Gym 3 PEL for chromium metal and insoluble salts (8-hour TWA: EPA Air-Environment N/A Under review D~nking-Water 50pg/L Regulation; current MCL, for total chromium; proposed MCL is 100 ~g/L ACGIH ~ American Conference of Governmental Industrial Hygienists; EPA = Environmental Protection Agency; NIOSH = National Institute for Occupational SafeW and Health; OS HA Occupational Safety and Health Administration t TWA (Tim+Weighted Average) = time-weighted average concentration for a normal workday and manhour workweek to which nearly all workers may be repeatedly exposed § PEL (Permissible Exposure Limit)
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From page 309... ...
Urinary excretion of proteins in chromeplaters, exchromeplaters and referents. Scand J Work Environ Health 1983;9:505-10.
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From page 310... ...
(1) The most important pathways for possible chromium exposure in this case are dermal contact during the unearthing of the sewage system; inhalation of emissions from the plant or soil particles If the pond dries up; and ingestion, if the drinking water has been contaminated by effluents from the plant.
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From page 311... ...
Persons who have developed lung cancer after chromium exposure were workers who had significant inhalation exposure for 2 years or longer. Because this patient's inhalation exposure is at ambient air levels and probably of 2 years duration at most, any increase in his relative risk would not be great.The patient should be advised to stop smoking cigarettes because smoking may act synergistically to increase risk and is itself a significant risk factor for lung cancer.
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