Histological examination of the lung tissue revealed alterations representing mild nonspecific irritation after exposure to 0.9 or 25 mg Cr(III) trichloride for 30 min. The respiratory system in animals is also a primary target for inhalation exposure to chromium. However, due to the tobacco smoking that cannot be excluded as a confounding factor, the increase in subjective respiratory symptoms and decreased pulmonary function parameters cannot be unequivocally be attributed to chromium exposure.
In an industrial hygiene survey of 60 ferrochromium workers exposed to Cr(III) and Cr(VI) (0.02-0.19 mg total chromium/m³) conducted in 1975, appreciably higher incidences of subjective symptoms of coughing, wheezing, and dyspnea were reported compared with controls. One man developed coughing, wheezing, and decreased forced volume after an inhalation exposure to a sample of Cr(III) sulfate. Occupational exposure to Cr(III) has also been associated with respiratory effects. workers found that the median time from date first employed to date of first diagnosis of nasal ulceration was less than a month the median Cr(VI) concentration was similar to concentrations reported in the Swedish study. The period of exposure for workers experiencing nasal mucosal ulceration varied from 5 months to 10 years. permissible exposure level in the workplace for chromates and chromic acid is 5 µg/m³ as a ceiling).
A 1983 study of 43 chrome-plating plants in Sweden, where workers were exposed almost exclusively to Cr(VI) acid, revealed that all workers with nasal mucosa ulceration or perforation were periodically exposed to at least 20 micrograms per cubic meter (µg/m³) when working near the plating baths (The newest U.S. Many cases of nasal mucosa injury (inflamed mucosa, ulcerated septum, and perforated septum) have been reported in workers exposed to Cr(VI) in chrome-plating plants and tanneries. A subsequent inhalation challenge with sodium chromate resulted in a reaction including late-onset urticaria, angioedema, and bronchospasm accompanied by tripling of plasma histamine levels. Consistent associations have been found between employment in the chromium industries and significant risk for respiratory cancer (see Carcinogenic Effects).Ī delayed anaphylactoid reaction was reported in a male worker occupationally exposed to chromium vapors from Cr(VI) trioxide baths and chromium fumes from stainless steel welding. Radiographic analysis from several reports revealed enlargement of the hilar region and lymph nodes. ulceration of the nasal mucosa with possible septal perforation.Pulmonary irritant effects following inhalation of chromium dust can include Dose, exposure duration, and the specific compound involved can determine chromium’s adverse health effects. Human occupational experience clearly indicates that, when inhaled, chromium compounds are respiratory tract irritants, resulting in airway irritation, airway obstruction, and lung, nasal, or sinus cancer. Occupational exposures often include mixed exposure to both Cr(III) and Cr(VI). Any of these species could attack DNA, proteins, and membrane lipids, thereby disrupting cellular integrity and functions. Ĭr(VI) enters many types of cells and under physiological conditions can be reduced by hydrogen peroxide (H2O2), glutathione (GSH) reductase, ascorbic acid, and GSH to produce reactive intermediates, including Cr(V), Cr(IV), thiylradicals, hydroxyl radicals, and ultimately, Cr(III). The balance that exists between extracellular Cr(VI) and intracellular Cr(III) is what ultimately dictates the amounts and rates at which Cr(VI) can enter cells and impart its toxic effects. If Cr(VI) is reduced to Cr(III) extracellularly, this form of the metal is not readily transported into cells and so toxicity is not observed. The reduction of Cr(VI) is considered to serve as a detoxification process when it occurs at a distance from the target site for toxic or genotoxic effect while reduction of Cr(VI) may serve to activate chromium toxicity if it takes place in or near the cell nucleus of target organs. It can be absorbed by the lung and gastrointestinal tract, and even to a certain extent by intact skin. Since Cr(III) is poorly absorbed by any route, the toxicity of chromium is mainly attributable to the Cr(VI) form.
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