Speciation of airborne dust from a nickel refinery roasting operation†

Abstract

Earlier work-related lung and nasal cancer studies included estimates of exposures to different nickel species in the refinery. Based on the metallurgy, only insoluble nickel was believed to be present around the roasters but mixed exposure was assumed in most areas, including the tankhouse. Occasional leaching tests of samples from the roaster area have indicated the presence of soluble nickel. This study reports on five parallel sets of dust samples collected from different floors with standard equipment and treated as follows. Two sets were leached with an ammonium citrate buffer at pH 4.4. Undissolved material was treated with HClO 4 /HNO 3 , evaporated to dryness and dissolved in HCl. Ni, Cu, Co, Fe, Se, and As were determined in both fractions. Water soluble Ni was found in all samples, ranging from 5-35%. Sulfate in the solutions correlated nearly stoichiometrically to the total metal content. The three remaining sets were investigated by, respectively, differential leaching, X-ray diffraction and scanning electron microscopy. The percentage of soluble nickel found by differential leaching corresponded well with those obtained by the simplified procedure. X-Ray diffraction analysis showed the presence of NiSO 4 •6H 2 O as well as oxides of Ni and Cu. This study indicates mixed exposures also in the roaster area. It also clearly indicates that basing exposure on the metallurgy alone can lead to serious misjudgements. The impact of this new information on the interpretation of cancer incidence at this refinery must await the analysis in an ongoing case-reference study.

Inorganic dust pneumonias: the metal-related parenchymal disorders.

“…Nickel refinery workers are exposed to both insoluble and water-soluble nickel species at work, including NiSO4.6H20 and nickel and copper oxides (177). These workers also have a significantly higher lung burden of nickel as measured in biopsy specimens by electrothermal atomic absorption spectroscopy.…”

Fractionation of nickel species from airborne aerosols: practical improvements and industrial applications

“…The method described here provides an improved fractionation of Ni species, based mainly on the procedure of Zatka et al (1992). In particular, a¯ow-injection analytical system for the sequential ®lter elutions renders it much less time-consuming and laborious than presently existing systems (Zatka et al 1992, Butler et al 1995Andersen et al 1998). The individual steps and solvents used to elute the Ni fractions have been optimised and adapted to the¯ow-injection procedure and the subsequent GF-AAS endpoint determination.…”

“…On the basis of an analytical fractionation of airborne nickel compounds into``water soluble'',`s ulphidic'',``metallic'' and``oxidic'' categories, (Zatka et al 1992) proposals have been made for the setting of dierential Occupational Exposure Levels (Anonymous 1996). A simpli®ed procedure, taking together the sulphidic, metallic and oxide nickel, has been described by Andersen et al (1998).…”

New views on the hypothesis of respiratory cancer risk from soluble nickel exposure; and reconsideration of this risk's historical sources in nickel refineries

“…pp5–6); and led to a 1998 speciation study at the refinery [26]. Its purposes were: to investigate if workers in the RSC department were exposed to soluble nickel, to demonstrate a speedier method for speciation than the Zatka et al .…”