Occupational exposure to beryllium in primary aluminium production

Abstract

Alumina used in the production of primary aluminium contains Be which partly vaporises from the cryolite bath into the workroom atmosphere. Since Be may be toxic at lower exposure levels than previously thought, the personal exposure to Be among workers in 7 Norwegian primary smelters has been assessed. In total, 480 personal Respicon® virtual impactor full shift air samples have been collected during 2 sampling campaigns and analysed for water soluble Be, Al and Na using inductively coupled plasma optical emission spectrometry. In addition, water soluble F(-) has been measured by ion chromatography. The Be air concentrations in the inhalable, thoracic and respirable aerosol fractions have been calculated. The Be concentrations in the inhalable aerosol fraction vary between the different smelters. The highest GM concentration of Be in the inhalable fraction (122 ng m(-3), n = 30) was measured in the prebake pot room of a smelter using predominantly Jamaican alumina where also the highest individual air concentration of 270 ng m(-3) of Be was identified. The relative distribution of Be in the different aerosol fractions was fairly constant with the mean Be amount for the two sampling campaigns between 44-49% in the thoracic fraction expressed as % of the inhalable amount. Linear regression analysis shows a high correlation between water soluble Be, Al, F and Na describing an average measured chemical bulk composition of the water soluble thoracic fraction as Na(5.7)Al(3.1)F(18). Be is likely to be present as traces in this particulate matter by replacing Al atoms in the condensed fluorides and/or as a major element in a nanoparticle sized fluoride. Thus, the major amount of Be present in the work room atmosphere of Al smelter pot rooms will predominantly be present in combination with substantial amounts of water soluble Al, F and Na.

Speciation of fluoride in workroom air during primary production of aluminium

“…Analysis of a typical exposed air lter, aer leaching with KOH, showed no signs of uorine in the undissolved particles, the applied leaching procedure was considered to dissolve airborne particles containing uorine. 25 The determination of F À by IC from this type of work room environment has previously been shown to be in good agreement with the use of ionselective electrode. 26 Gas lters Impregnated gas lters (10% (w/v) KOH solution on Millipore AP1002500 support pads) were transferred to 15 mL polypropylene tubes (Art.…”

“…33 Previous studies have shown the presence of ultrane particles in both Søderberg and Prebake pot rooms, and suggested that such particles to a high degree are formed by condensation of vaporized uorides under supersaturation conditions. 5,25,34 This study shows that the relative amount of F WS À is dependent on particle size and that the solubility decreases with increasing particle size.…”

“…Details have been published. 25 The DLs for F WS À in the respirable, thoracic and inhalable aerosol sub-fractions were 5.0, 7.1 and 8.7 mg per lter, respectively. Alkaline-soluble uoride (F AS À ) was dened as the amount of F À in the collected aerosol mass that remained aer leaching the F ws À and that dissolved in 5 mL 0.5 M potassium hydroxide (KOH) solution at 75 C within 90 min.…”

Cancer Risks in Aluminum Reduction Plant Workers

“…Brass and iron/titanium oxides were also found in small amounts 23. Beryllium levels (around a hundredth to a tenth of the threshold limit value of 2 μg/m 3 ) were also measured in aluminum smelters in Norway24 and in the United States 25. The highest concentrations were in a prebake potroom where Jamaican alumina was used 24…”

Beryllium Concentrations at European Workplaces: Comparison of ‘Total’ and Inhalable Particulate Measurements

“…Due to lack of size resolution of the Marple impactor in the size range >10 µm, the upper value of 14 µm of the mass median aerodynamic diameter (MMAD) is probably underestimated. Measurements of Be concentrations in the aluminium industry were reported by Skaugset et al (2012) . From the analysis of Respicon samples, it was found that on average, ~50% of the Be was associated with particles in the extra-thoracic size regime.…”