A Health Surveillance Study of Workers Employed at a Copper Smelter—Effects of Long-Term Exposure to Copper on Lung Function Using Spirometric Data

Abstract

Objective: Significantly lower permissible occupational exposure limits for copper dust are being discussed in Europe and other jurisdictions. However, little data are published on exposures in occupational settings and copperspecific effects in humans. Hence, a health surveillance study was performed among workers employed at a copper smelter between 1972 and 2018. Methods: Possible effects of long-term exposures to dust containing copper on lung function were assessed. Specifically, declines in forced expiratory volume in 1 second (FEV 1 ) were compared between a copper-exposed and control group. Cumulative copper exposures were derived from historical airborne monitoring data. Results: FEV 1 declines among exposed and control never smokers were similar to a typical age-dependent decline of 29 mL/y. Conclusion: The study findings indicate that cumulative inhalable copper dust exposure averaging 4.61 mg/m 3 -years over an exposure duration of $22 years is not associated with adverse effects on lung function.

Cross-sectional Study of Workers Employed at a Copper Smelter—Effects of Long-term Exposures to Copper on Lung Function and Chronic Inflammation

“…In light of these observations, the results do not indicate any exposure-dependent impairment of the lung function in relation to copper exposure, and this is consistent with previous findings. 8 As expected, the effect of smoking was evident in the study population. In line with literature data, we observed a significant increase in blood leukocytes, neutrophils, 35 and immunoglobulin E 36 and a decrease in the percentage of blood monocytes in the current smokers.…”

“…Process conditions in both facilities and copper dust exposure levels in the smelter between 1982 and 2018 were described previously. 8 The inhalable copper dust exposure level during the study period was approximately 0.120 mg/m 3 (based on n = 12 measurements in 2018) and similar to earlier years. 8 Participants employed at the copper smelter (ie, copper-exposed study subjects) were categorized into constant RPE users, occasional RPE users, and never RPE users.…”

“…8 The inhalable copper dust exposure level during the study period was approximately 0.120 mg/m 3 (based on n = 12 measurements in 2018) and similar to earlier years. 8 Participants employed at the copper smelter (ie, copper-exposed study subjects) were categorized into constant RPE users, occasional RPE users, and never RPE users. Respiratory protective equipment use (full-face mask with air supply) became mandatory in the copper facility on February 1, 2019, to provide greater protection from exposure to arsenic and cadmium.…”

“…Our observations of a lack of copper exposure–related effects on lung function are consistent with a historical health surveillance study performed at the same copper plant that focused on the decline in FEV 1 over a mean exposure duration of approximately 22 years. Declines in FEV 1 among copper-exposed and referent never smokers were similar to the typical age-dependent decline in a healthy nonsmoking reference population 8,52 . The current study included a more sensitive assessment of lung function measures as well as inflammatory biomarkers to elucidate possible subtle effects, which might have been missed in the historical health surveillance study.…”

“…This reflects the increased particle load in the lungs and is designed to rid the airspaces of particles as part of a homeostatic response rather than part of a process that leads to pathological change. Coexposures to other inorganic dust particles including metals occurring in the refinement process of copper, lead, and precious metals were discussed in detail in the health surveillance study 8 . Respiratory protective equipment use became mandatory in the lead area in 2003, and therefore, an impact of mixed metal/GBS exposure on current workers in the lead area examined in 2019 was unlikely.…”