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Copper- and zinc-containing welding fumes are able to induce systemic inflammation.

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Zinc-and copper-containing welding fumes increase systemic C-reactive protein (CRP). The aim of this study was to investigate the performance of the biomarkers serum amyloid A (SAA) and soluble vascular cell adhesion molecule-1 (VCAM-1) in this regard. Fifteen male subjects were exposed under controlled conditions to welding fumes containing either zinc, or copper, or copper and zinc for 6 h. Plasma samples were collected before, 6 and 24 h after start of exposure and biomarkers therein were measured by electrochemiluminescent assay. For each exposure, systemic concentrations of systemic SAA, but not VCAM-1, increased significantly at 24 h after exposure start compared with baseline ("copper only": P = 0.0005, "zinc only": P = 0.027, "copper and zinc": P = 0.001). SAA showed a wider range of concentrations than did CRP and its levels increased up to 19-fold after welding fume exposure. The recognition of copper as a potential harmful component in welding fumes, also independent from zinc, deserves further consideration. SAA might represent a new sensitive biomarker for potential subclinical sterile inflammation after inhalation of copper-and/or zinc-containing welding fumes. As elevations of CRP and SAA protein have both been linked to a higher risk for cardiovascular disease, these findings might particularly be important for long-term welders. Journal of Exposure Science and Environmental Epidemiology INTRODUCTIONA large number of workers are exposed to welding fumes containing various types of gases and metal particles in occupational settings. Depending on the constitution of the welding fumes and the respective exposure conditions, epidemiological studies have shown that welding fume exposure is associated with the risk of health impairment through respiratory illness, inflammation and cardiovascular disease. [1][2][3][4] Zinc and copper play an increasing role in modern joining technology, especially in the automotive industry, and hence exposures from workers become more frequent. In a recent study, a distinct increase of systemic C-reactive protein (CRP) has been shown after inhalation of welding fume from a metal inert gas brazing process of zinc-coated steel using a copper-containing welding wire at an average fume concentration of 2.5 mg/m 3 . 5 A further study tested the effect of elevated systemic CRP levels after exposure with three different doses of this welding fume and found increases of CRP after exposure with 2.0 and 2.5 mg/m 3 average fume concentration, but not at 1.4 mg/m 3 . Hence, it was concluded that the no-observed-effect level for systemic inflammation after such exposures was 1.4 mg/m 3 and the lowest observed effect level was 2.0 mg/m 3 . 6 This corresponds to zinc concentrations of 0.84 mg/m 3 and 1.2 mg/m 3 , respectively, and copper concentrations of 0.24 mg/m 3 and 0.34 mg/m 3 , respectively. 6 A subsequent third study showed that the observed effects were due to the zinc as well as copper present in the welding fume, as the welding fumes which contained either zinc and no cop...