Collection, validation and generation of bitumen fumes for inhalation studies in rats. Pt.3: Regeneration of bitumen fumes, inhalation setup, validation

Undertaking a chronic inhalation study on bitumen fume presents a challenge in terms of generating sufficient amounts of representative fume. The objective of the study described in this and in previous publications was to collect sufficient fume and use this to develop a laboratory-generated exposure atmosphere, for use in chronic inhalation toxicity studies in rats that resembles, as closely as possible, personal exposures seen in workers during road paving operation. To achieve this goal, atmospheric workplace samples were collected at road paving work sites and compared with bitumen fume condensate samples collected from the headspace of hot bitumen storage tanks. In Parts 1 and 2, we described the collection and analysis of workplace samples, the strategy for in-line extraction of a suitable fraction of bitumen fume collected from the headspace of a bitumen storage tank and the comparison of the collected condensate to the workplace samples. This paper (part 3) describes the regeneration of bitumen fume for inhalation and the exposure setup used for inhalation studies.