Particle Size Characterizations of Copper and Zinc Oxide Exposures of Employees Working in a Nonferrous Foundry Using Cascade Impactors

Abstract

This study characterized exposures to copper and zinc oxide as respirable or nonrespirable using personal impactors and compared the results with previous findings obtained using cyclones. Twenty-five sets of air samples were taken over a 10-month period using single jet cascade impactors. Five to six stages were used to capture and classify aerosols according to their aerodynamic diameter (d(ae)). These ranged from < 0.5 microm to > 10 microm d(ae). Twenty-two air samples were taken on employees casting brass alloys, and three samples were taken in areas in the vicinity where employees routinely worked. Twenty-one air samples were taken during the casting of a single brass alloy (containing 70% copper and 30% zinc), and the remaining samples were obtained from employees casting two different brass alloys: a nearly pure copper alloy and a nickel-copper alloy. The results indicated that 55-96% (by mass) of all copper aerosols collected had a d(ae) > or = 10 microm. More than 85% (by mass) of all copper exposures were estimated as nonrespirable using the current ACGIH-CEN-ISO definition. Zinc oxide aerosols were collected at all stages of the impactors, with significant amounts found to have a d(ae) > or = 10 microm. More than 60% (by mass) of all zinc oxide exposures were estimated to be nonrespirable. A comparison of data collected using impactors and cyclones demonstrated that cyclones could be used to differentiate larger aerosol particles from fumes, rather than requiring the use of impactors. It is recommended that appropriate particle size selective sampling methods be used to classify exposures of metals to dusts and fumes.

Zinc exposure for female workers in a galvanizing plant in Northern Italy

“…Our results are therefore consistent with the hypothesis that the respiratory tract is able to absorb zinc following inhalation [1,14,16,17,20,21,24,29,40]. In this regard, both experimental and field studies suggest that zinc and zinc oxide are efficiently adsorbed by airborne dusts [45,46]: impacting upper airways, 35% to 80% of zinc-enriched particles would be retained, swallowed and eventually absorbed through the gastrointestinal tract, the absorption rate of which would depend on the nutritional status, ranging between 8% and 80% [1,14,16,17,20,21,31,45]. As environmental sampling identified an airborne concentration of 1.58±0.34 mg/m 3 for dusts having aerodynamic diameter < 10 μm, a significant role for this exposure route may therefore be supposed.…”

“…As environmental sampling identified an airborne concentration of 1.58±0.34 mg/m 3 for dusts having aerodynamic diameter < 10 μm, a significant role for this exposure route may therefore be supposed. Despite animal studies on ZnO fumes that collectively suggest that a rapid and transient increase of serum zinc may follow the exposure [45,46], we have been unable to identify either such post-exposure peak or any correlation with the external exposures, as it was the case with some previous occupational studies [14,29,31]. These results may found several speculative explanations.…”

Quantification of Low Pressure Impactor Wall Deposits during Zinc Nanoparticle Sampling

“…They are widely used in various fields for characterizing aerosols, such as environmental dust and haze (e.g., Kang et al, 2013), coals (e.g., Wang et al, 2007;Kazanc et al, 2013), urban aerosols (e.g., Maenhaut et al, 2002;Salma et al, 2002;Wagner et al, 2008;Xie et al, 2009), drugs (e.g., Klemmer et al, 2013;McBride et al, 2013;Sultana et al, 2013;Zhu et al, 2014), and bacterial aerosols (e.g., Simon et al, 2013;Li 2013). In addition, impactors are commonly used for characterizing workplace environments (e.g., Cohen and Powers 2000;Chen et al, 2007;Wu and Vincent, 2007;Dahlin et al, 2008a;Dahlin et al, 2008b;Dall'Osto et al, 2008;Linnainmaa et al, 2008;Birch et al, 2011;Yang 2011;Coggins et al, 2012;Ehrlich et al, 2013). Most of them (MOUDI, ELPI, DLPI, BLPI, QCM impactor, etc.)…”

Evaluation of a prototype inhalable sampler

“…Specifically, in the analysis of particles emitted from foundry pouring operations, Cohen and Powers (2000) reported that only 2% of the measured aerosol had an aerodynamic diameters smaller than 1 µm and that 70% of the aerosols were larger than 5 µm. Cohen and Powers (2000) also suggested that due to the variety and variability of particle sizes emitted in foundries, air sampling methods that do not discriminate by particle size, (i.e., a 37-mm cassette) should be used as an appropriate screening tool.…”

“…In general, three samplers have been used to collect particles and assess respective concentrations produced from metals processes: the 37-mm cassette, which can be operated both open-or closed-face, as well as the Institute of Medicine (IOM) or Button (Brisson & Archuleta, 2009;Hobson et al, 2011;Zugasti et al, 2012). Cohen and Powers (2000) advised the use of the 37-mm cassette "total" dust sampler to assess particles emitted in foundries and stated that it does not discriminate by particle size. Additionally, both the National Institute for Occupational Safety and Health (NIOSH) and OSHA particle sampling methods specify the use of the 37-mm cassette for sampling Particulates Not Otherwise Regulated (PNOR) as well as metal and metalloid particles (OSHA, 2004) Repeated studies of the 37-mm cassette both open-and close-faced have revealed the sampler under samples particles larger than 30 to 45 µm and accordingly, it does not match the IPM curve (Aizenberg et al, 2000;Kenny et al, 1999;Kenny et al, 1997;Liden et al, 2000;Mark & Vincent, 1986).…”