Metal toxicity and the respiratory tract

Abstract

The type of lung disease caused by metal compounds depends on the nature of the offending agent, its physicochemical form, the dose, exposure conditions and host factors. The fumes or gaseous forms of several metals, e.g. cadmium (Cd), manganese (Mn), mercury (Hg), nickel carbonyl (Nl(CO)4, zinc chloride (ZnCl2), vanadium pentoxide (V2O5), may lead to acute chemical pneumonitis and pulmonary oedema or to acute tracheobronchitis. Metal fume fever, which may follow the inhalation of metal fumes e.g. zinc (Zn), copper (Cu) and many others, is a poorly understood influenza-like reaction, accompanied by an acute self-limiting neutrophil alveolitis. Chronic obstructive lung disease may result from occupational exposure to mineral dusts, including probably some metallic dusts, or from jobs involving the working of metal compounds, such as welding. Exposure to cadmium may lead to emphysema. Bronchial asthma may be caused by complex platinum salts, nickel, chromium or cobalt, presumably on the basis of allergic sensitization. The cause of asthma in aluminium workers is unknown. It is remarkable that asthma induced by nickel (Ni) or chromium (Cr) is apparently infrequent, considering their potency and frequent involvement as dermal sensitizers. Metallic dusts deposited in the lung may give rise to pulmonary fibrosis and functional impairment, depending on the fibrogenic potential of the agent and on poorly understood host factors. Inhalation of iron compounds causes siderosis, a pneumoconiosis with little or no fibrosis. Hard metal lung disease is a fibrosis characterized by desquamative and giant cell interstitial pneumonitis and is probably caused by cobalt, since a similar disease has been observed in workers exposed to cobalt in the absence of tungsten carbide. Chronic beryllium disease is a fibrosis with sarcoid-like epitheloid granulomas and is presumably due to a cell-mediated immune response to beryllium. Such a mechanism may be responsible for the pulmonary fibrosis occasionally found in subjects exposed to other metals e.g. aluminium (Al), titanium (Ti), rare earths. The proportion of lung cancer attributable to occupation is around 15%, with exposure to metals being frequently incriminated. Underground mining of e.g. uranium or iron is associated with a high incidence of lung cancer, as a result of exposure to radon. At least some forms of arsenic, chromium and nickel are well established lung carcinogens in humans. There is also evidence for increased lung cancer mortality in cadmium workers and in iron or steel workers.

Association between exposure to specific PM 2.5 constituents and environment, lifestyle, and clinical parameters in patients with COPD

“…In our current study, several chemical constituents of PM 2.5 correlated with poorer respiratory outcomes and some had associations across multiple outcomes (Br, Ca, Fe, Mn, Pb, Si, and Zn). Although exposure to metal dust or fumes can cause serious cardiopulmonary complications (Bergström, 1977;Merget et al, 2002;Nemery, 1990;Woolf and Shannon, 1999;Zhou et al, 2018), these chemicals as particulate matters may have different mechanisms involved in their hazardous effects. The adverse health effects of PM 2.5 exposure are considered to be mediated by oxidative stress through the generation of reactive oxygen species, in ammation, and mitochondrial damage (Thangavel et al, 2022), with some PM 2.5 constituents sharing similar mechanisms.…”

Metal Exposure-Related Welder’s Pneumoconiosis and Lung Function: A Cross-Sectional Study in a Container Factory of China

“…Mn, a known neurotoxicant, would originate from the welding electrode and base metals and could act as a deoxidizing agent to increase the strength of the resultant weld [ 61 ]. A population-based study showed that Mn in welding fume and aging might make welders more susceptible to Alzheimer’s disease or related disorders [ 62 ]. In comparison, Zn may be derived from anti-rust painting on pipeline surfaces and additives to welding fillers of electrodes or materials.…”

Understanding Pneumoconiosis, A Misdiagnosed Subtype of Diffuse Interstitial Lung Disease

“…In addition, highintensity, brief exposure to iron dust can also result in future symptoms [98]. It is important to realize that exposure to silica or asbestos is not uncommon in many jobs involving iron exposure, thus giving rise to mixed dust fibrosis or to asbestosis, which has associated morbidity and complications [99].…”

“…However, atypical radiologic findings rarely appear, which may be misdiagnosed as other diseases [100]. In addition, with the cessation of exposure, the radiographic opacities may gradually disappear [99]. At the time of welding, the aspirated iron oxide is stored in alveolar macrophages and then transferred to the lung parenchyma.…”