This study was aimed at characterizing the exposure profiles for carbon black manufacturing workers. Personal sampling was conducted on 8 wet pelletizing workers and 22 packaging workers. A sampling train consisted of an IOM personal inhalable aerosol sampler (to collect airborne dusts and their inherent particle-bound polycyclic aromatic hydrocarbons (PAHs)), and an XAD-2 sorbent tube (to collect gaseous PAHs) was used. For PAHs analyses, 21 PAH species were analyzed by using the gas chromatograph/mass technique. In addition, size segregating sampling was conducted at both workplaces, by using both the Micro-orifice Uniform Deposited Impactors (MOUDI) and the Noll Rotary Impactor (NRI) simultaneously to characterize the particle size distributions exposure to both exposure groups. Results show that the packaging workers had a higher dust exposure level (arithmetic mean=1.17 mg/m3) than the pelletizing workers (arithmetic mean=0.82 mg/m3). Although both levels were lower than the time-weighted-average threshold limit value (TLV-TWA) of 3.5 mg/m3 of ACGIH, about 7.48% of the packaging workers were estimated to be above the limit value. A significant amount of gaseous PAHs was also found in personal exposure, especially BaP and PER in the gaseous phase were similar to those found in the particle-bound phase. Exposure to particle-bound PAHs was considered due to the releasing of carbon black dusts during the pelletizing and packaging processes, but for gaseous PAHs, it might be due to the emission of gaseous PAHs from the feedstock oil unloading process rather than the stack flue gas. The above findings suggest that both gaseous and particle-bound PAHs are equally important in assessing exposure of carbon black industry workers. Size distributions, including both airborne dusts and particle-bound PAHs, collected from both areas were found in the form of bimodality. No statistical difference could be found between the airborne dust size distribution and the corresponding particle-bound PAH size distribution in the two areas, which suggests that workers in both areas might be exposed to similar types of airborne dust that contain similar PAH compositions.
All Science Journal Classification (ASJC) codes
- Public Health, Environmental and Occupational Health