Agency for Toxic Substances and Disease Registry
Case Studies in Environmental Medicine (CSEM) 

Chromium Toxicity
Answers to Pretest and Challenge Questions

Pretest

1. A problem list for this patient would include upper and lower respiratory irritation, multiple skin lesions and edema of the hands, loss of appetite and weight loss, liver and renal dysfunction, and cigarette smoking.
2. Information suggesting an environmental etiology includes the following: onset of the patient's symptoms coincides with activity outside the usual routine; in addition, the patient mentions that he first noticed the sores on his hands and forearms while digging up the sewage system to make repairs. Another clue to a possible environmental cause is temporary relief of symptoms when the patient leaves his usual habitat, such as when he visited Chicago. Proximity of the patient's home to an industrial facility (i.e., the electroplating plant) is also an important clue.
3. You might identify possible causes for the dermal lesions by consulting with a dermatologist. The cause of the persistent respiratory symptoms (2 to 3 months) that do not respond to OTC decongestants in a person with no history of allergies should be pursued; the patient should be queried about whether the onset of symptoms coincided with the move to his home, whether odors have emanated from the plant, and so forth. More information regarding the patient's observations and activities while digging up the sewage system may also be helpful.
4. See answer to Challenge question 8.

Challenge

1. If effluent from the plant has reached the groundwater, community residents who drink well water might be at risk. Airborne plant emissions might have also reached nearby residents. Plant workers who prepare the plating baths and work near them might be receiving significant exposure.
2. 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.

   Minor inhalation sources of chromium might include road and cement dust, erosion products of brake linings and emissions from automotive catalytic converters, and tobacco smoke. Cigarettes contain 0.24 mg/kg to 14.6 mg/kg chromium, although it is not known how much of this is inhaled. Foodstuffs (ingestion) generally contain extremely low chromium levels.

3. Cr (VI) is a powerful oxidizing agent. In the plasma and cells, it is readily reduced to Cr (III), which is excreted in the urine.
4. Yes. Persistent dermal ulcers, respiratory tract irritation, and pulmonary sensitization are all possible effects of chromium exposure.
5. Although it cannot be ruled out, it is unlikely that the dermal and inhalation chromium exposure of this patient will cause lung cancer. Workers who had significant inhalation exposure to chromium for 2 years or longer have developed lung cancer. 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. The data are insufficient to estimate the risk from ingestion of the contaminated drinking water.
6. If exposure was recent, chromium levels in blood or urine may be used to confirm exposure. Renal function should be tested (urinalysis, blood urea nitrogen, creatinine, and β₂-microglobulin) to determine if renal tubular damage has occurred.
7. No useful interpretations can be drawn from the hair analysis. A result of 1,038 ppm is beyond the range for unexposed persons (50 ppm to 1,000 ppm); however, the sample could have been environmentally contaminated with chromium from the water during bathing, or by chromium in ambient air polluted by the plant emissions. No standard methods exist for obtaining a hair sample or for washing and preparing the sample for analysis, and these techniques can greatly influence results. Finally, no research exists to prove a correlation between chromium content of hair and exposure levels or physiologic effects; therefore, the result has no clinical significance.
8. If the sources of chromium exposure can be eliminated for this patient, no further treatment would be required, except for the skin lesions. Topical ascorbic acid has been useful in the treatment of chrome ulcers, and 1% aluminum acetate wet dressings can be used to treat the dermatitis.

   This patient's case might be a sentinel for community exposure. You should contact the local health department, OSHA, and EPA to report your patient's adverse effects and discuss your suspicions of the chromium source. Chromium levels in and around the plant should be measured. If a hazard exists, workers should be provided proper protective gear, trained, and medically monitored. Because EPA does not have an emission standard, it might be difficult to abate the atmospheric source of chromium. Decontamination of the pond might require regulatory action and litigation. Residents who use well water should be encouraged to use an alternative water source for drinking and cooking.

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