Health Risk Assessment of Occupational Exposure to Chemical Materials in a Combined-Cycle Power Plants

Background: This study was an attempt to assess occupational exposure of the workers in a combined-cycle power plant in the southwest of Iran, based on the route of inhalation exposure of emissions in the workplace. Methods: For this purpose, the main potential sites for pollutant emissions were considered adjacent to the sites of "use and injection of chemicals into the process". Sulfuric acid, sodium hydroxide, ammonia, oil mist, toluene, hydrogen sulfide, hydrazine, and tetrachloromethane were measured and analyzed using the NIOSH standard. Dose-response assessment was estimated using Unit Risk Inhalation (IUR) for cancer risks and Reference Concentration (RFC) and Reference Exposure Levels (REL) for non-cancer risks. Risk characterization performed, using Office of Environmental Health Hazard Assessment guideline. Results: The results showed that ammonia and toluene had the highest and lowest concentration of pollutants emitted in workplace, respectively. The inhalation of ammonia and sulfuric acid and their daily absorption were at high risk (HQ>۱). Other noncancerous compounds had HQ<۱. While the HI (Hazard Index) for total non-cancer risks was ۵.۳۴E+۰۱ (HI>۱), it was likely to have non-cancerous risks. For carcinogenic risks, they were calculated to be ۹.۵۸E-۰۳ and ۵.۴۷E-۰۴ for hydrazine and tetrachloromethane, respectively. The total carcinogenic risk of the emissions was calculated at ۱.۰۱E-۰۲, which was in the significant range (more than ۱۰-۴), i.e. in the range of hazardous cancer effects.Conclusion: In this study, it confirmed the possibility of non-carcinogenic risks. Also, the quantity of cancer risks was within the range of "Significant", indicating the probability of carcinogenic risks.

Keywords:

Health risk assessment , emissions , cancer and non-cancer risk , Combined-cycle Power Plants , Inhalation route