Beryllium solubility in occupational airborne particles: sequential extraction procedure and workplace application

An existing sequential extraction procedure for inorganic beryllium species in the particulate matter of emission and working areas was adapted for closed-face cassette. The speciation protocol was optimised for being adapted for a direct extraction in cassettes to take into account wall deposits. This four step sequential extraction procedure aims to separate beryllium salts, metal, oxides and residuals which will be individually quantified. The characterisation of the beryllium species according to their solubility in air sample will provide information concerning toxicity as it has been shown that it is related to beryllium chemical form. Beryllium salts (BeF2, BeSO4), metal (Bemet), and oxide (BeO) were tested individually then in mixture. Cassettes were spiked with this species and recoveries were calculated. Matrix matching quantitative analyses were realised by inductively coupled plasma mass spectrometry (ICP-MS). Limits of detection (LODs) have been calculated for the four matrices used in the different steps of extraction. For all matrices, LODs were below 4.4 ng/sample, adapted to beryllium occupational exposure assessment regarding lowest recommended threshold limit value of 0.01 µg.m-3 and 0.05 µg.m-3 in France (ANSES, 2010) and USA (ACGIH, 2009). The protocol has been then tested on samples from French factories for which an occupational beryllium exposure was suspected. Beryllium solubility is variable between factories and among the same workplace between different tasks.