Thesis (M.Sc.) - Asian Institute of Technology - Chulabhorn Research Institute - Mahidol University, 2007

Aircraft emission consists of a variety of carcinogenic air pollutants such as PAHs (class 2A probably carcinogenic to human, IARC) Effect of exposure to PAHs in airport workers has not been previously reported in Thailand. Therefore, the principal objective of this study was to assess occupational exposure through the use of biomarker and evaluate health risk in apron workers. The study was conducted at Suvarnabhumi International Airport. Determination of PAHs and naphthalene was carried out in ambient level and individual level. Levels of urinary 1-OHP and 2-NAP, as biomarker of exposure, were determined. Moreover, the level of cotinine was measured in order to assess the influence of tobacco smoke on the study biomarker. The study was carried out in 30 apron workers (20 ground equipment operators and 10 aircraft technicians) and matched controls (30 office workers). Ambient air monitoring revealed a higher level of particle bound PAHs in apron. Total PAHs measured in apron ambient was significantly higher than controls (4.30 vs. 1.40 ng/m³, P<0.001) which the level of fluoranthene (0.85 ng/m³), B[g,h,i]P (0.65ng/m³) and pyrene (0.54 ng/m³) were predominant. The level of B[a]P and B[a]P eq was 0.39 and 1.32 ng/m³, respectively, which was 2 times higher than control. Exposure level of PAHs and naphthalene in apron workers were significantly higher than those of control (3.90 vs. 1.31 ng/m³ for PAHs, and 2.01 vs. 4.37 ug/m³ for naphthalene, P<0.001). Increased levels of B[a]P and B[a]Peq were observed in apron workers which was 2 times greater than control. The major PAHs measured in apron workers was predominated in pyrene (0.86 ng/m³), B[g,h,i]perylene (0.54 ng/m³) and fluoranthene (0.53 ng/m³). A similar pattern of PAHs in apron ambient, and individual exposure suggested that apron workers exposed to PAHs in working environment. The level of urinary 1-OHP and 2-NAP in apron workers were significantly higher than those of control (P<0.005). Moreover, increased 1-OHP and 2-NAP level during work shift was also observed in apron workers (P<0.001 for 1-OHP and P<0.005 for 2-NAP). The level of urinary cotinine measured in both controls and exposed workers was not exceeded than cut-off values (40 ug/m mol Cr), hence, there was no major contribution from tobacco smoke. However, correlation between PAHs exposure level and biomarker of exposure in this study were not statistically significant. Excess life time cancer risk (ELCR) derived from corresponding concentration of B[a]P in all apron workers, ground equipment operators and aircraft technicians were 1.61 x 10⁻⁴, 1.58 x 10⁻⁴ and 1.64 x 10⁻⁴, respectively. This was approximately 3 times greater than office workers. Although exposure level of PAHs and naphthalene in apron workers was lower than the occupational standard setting recommended by NIOSH and OSHA, which are 0.2 mg/m³ and 50 mg/m³ TWA8 for PAHs and naphthalene, respectively. However, an increase in ELCR in apron workers would increased health risk of occupationally exposed to PAHs.

A thesis submitted in partial fulfillment of the requirements for the degree of Master of Science in Environmental Engineering and Management Inter-University Program on Environmental Toxicology, Technology and Management.