The current study was conducted to study air pollutants emitted in WWTP, as well as to assess the exposure levels of pollutants and their health risks to workers and nearby residents using a modelling method for United States Environmental Protection Agency (US EPA). Outdoor concentrations of CO, H2S, NH3, SO2, NO2, TVOCs, PM1, PM2.5, PM10, and TSP were detected in 30 sites inside Abu-Rawash wastewater treatment plant, Egypt. Concentration distributions of air pollutants were plotted on contour maps using Software Surfer 13.
The results showed that concentration levels of all pollutants were below the permissible thresholds limits set by the Egyptian Environmental Law No. 4 of 1994. Concentration distributions of gaseous pollutants and particulate matter show two hotspots in Abu-Rawash WWTP identified at the northwest of the plant.
Non-carcinogenic risks were evaluated and the results showed that the hazard quotient (HQ) was less than 1 for all air pollutants, except H2S and TVOCs. This indicates that there is adverse chronic health effects occurred due to H2S, and TVOCs exposure. In addition, Hazard index (HI) of pollutants was (57.3) greater than 1; indicating that there is adverse chronic health effects could be induced by exposure to pollutants in Abu-Rawash WWTP. Furthermore, carcinogenic risk of TVOCs was evaluated as lifetime cancer risk (LCR) which was (0.0513) greater than 10-4; indicating a high risk of developing cancer for exposed person.