| Human Toxicity Excerpts | /OTHER TOXICITY INFORMATION/ Oral ingestion of iron is a potentially fatal occurrence, and ingestions of over 30 mg/kg body weight should be considered for hospital admission for observation depending on clinical symptoms and findings ... ./HUMAN EXPOSURE STUDIES/ Metallic iron foreign bodies in cornea...produce "rust ring" of yellow-brown staining... this is often associated with sensation of irritation, hyperemia of conjunctiva, and inflammatory cells in anterior chamber in patient./EPIDEMIOLOGY STUDIES/ A retrospective cohort mortality study was conducted... among 8,147 men and 627 women employed in a gray iron foundry for at least 6 months between 1950 and 1979. More than 1700 deaths occurred during a 35 yr period of observation. Standardized mortality ratios (SMRs) for all causes were close to expected values, based on the U.S. general population as the standard. The mortality of nonwhite men was significantly increased for lung cancer (SMR=132) and ischemic heart disease (SMR=126). Other moderate, but non-significant, excesses were noted among nonwhite men for cancers of the stomach, pancreas, and prostate, for diabetes melitus, and for pulmonary emphysema, and among white men for cancers of the lung and stomach, gastric and duodenal ulcers, pulmonary cerebrovascular disease. The lack of a trend with time since hire and duration of foundry employment suggests that lung cancer mortality may not be associated with exposure to the foundry environment. Utilizing indirect measures of smoking, it appears that virtually all excess lung cancer deaths among whites, and at least some of the excess among nonwhites, could be explained by smoking habits. Similarly, smoking may have been responsible for the mortality excesses from emphysema, cerebrovascular diseases, and ischemic heart disease./EPIDEMIOLOGY STUDIES/ ...An increase of bronchial obstruction due to exposure in an iron foundry /was shown/. In a 100 subject sample, all working in the iron foundry were affected only by small airway obstruction. Thirty months later, 99 of these subjects were reexamined and the present airway condition determined. In 43 subjects there were abnormal results of the tests, indicating total airway obstruction after 30 months. Even in the subsample of nonsmokers, a deterioration had occurred./OTHER TOXICITY INFORMATION/ The extent and intensity of the spread of siderosis is influenced by the site of the foreign body. Iron particles in the cornea or sclera principally have local effects. Particles in the anterior chamber may slowly rust and slowly be washed away by the flow of aqueous humor, causing siderosis only in the anterior chamber. In the lens, metallic iron causes lenticular siderosis, but may have little effect on the posterior portions of the eye. The most widespread and serious spread of iron comes from particles in the posterior part of the globe, in the vitreous humor, or in the neighborhood of the ciliary body. The larger the particle and the less encapsulated by dense tissue, the more rapid and extensive the siderosis. The rate at which siderosis develops varies greatly, but signs are usually evident within a few weeks or months. In some cases iron foreign bodies are so small or so unreactive that no significant toxic effects develops over many years. In the cornea, iron particles very rapidly produce a "rust ring" staining the immediately surrounding cornea the color of rust. This is often associated with initation and discomfort hyperemia of the conjunctiva, and inflammatory cells in the anterior chambers. ... /Iron particles/ |
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