Semi-quantitative risk assessment of occupational exposure area industrial wastewater Treatment unit in an oil refinery and chemical contaminants

Background and aims: The chemical pollution in industries has make an unacceptable risk for the human health. For the risk assessment of the human exposure, it is necessary to be considered the material dangers based on the consumption rate, dose, toxic properties, and evaluation of potential effects on the human health. Therefore, the aim of this study was to assess the semi-quantitative risk of the occupational exposure to chemical contaminants among workers of the industrial wastewater unit in an oil refinery as a model to predict the exposure.  Methods: This descriptive-analytic study was performed in the industrial wastewater unit of Abadan oil refinery in 2016. After the similar exposure groups (SEGs) were determined and information were collected, fourteen materials were measured by the short-time personal sampling and real-time monitoring methods using the ION- First Check. The exposure rate of workers to chemical contaminants was determined using the Industrial Hygiene Statistics software (IHS) based on the results of the sampling and analysis. At the first, the Exposure Rate (ER) and then the Hazard Rate (HR) were calculated to determine the exposure risk level. Results: Based on the results of this study, pools were cleaned four times per day and fourteen hours per week by workers. The results showed that weekly exposure of workers to ethylene oxide (16.7 ppm), nitrobenzene (16 ppm), and nitrogen dioxide (15 ppm) had the highest values, respectively. Lowest values of the exposure were related to the carbon monoxide (2.8 ppm) and carbon disulfide (1.5 ppm), respectively. Benzene (12.5), ethylene oxide (10), acrolein (10), nitro benzene (7.5), hydrogen sulfide (7.5), hydrogen peroxide (7.5) and aniline (6) had the highest risk level, respectively. Conclusion: The results of the present study showed that workers of the industrial wastewater unit have a very high risk level of the exposure to chemical contaminants. Therefore, the prioritization of control measures such as new wastewater treatment methods using the semi-quantitative health risk assessment is one of the most important ways to prevent and decrease the exposure of workers to contaminants.