Health risk assessment of exposure to chemical pollutants in the industries of Shahid Salimi Industrial zone using the Monte Carlo simulation method

Abstract

Objective: Nowadays, the use of chemicals in human life is unavoidable. Workers in various industries are widely exposed to various chemical pollutants. Considering the serious effects of chemicals on health, the need for a comprehensive risk assessment program is necessary to determine the level of risk of hazardous chemicals and to determine high-risk industrial groups. Therefore, the present study has investigated the health risk assessment of exposure to chemical pollutants in the industries of Shahid Salimi Industrial Town using the Monte Carlo simulation method. Methods: This descriptive study was conducted in Salimi Industrial Town in 5 stages. First, the common pollutants and indicators of each industrial group (benzene, toluene, ethylbenzene, xylene, acetic acid, vinyl chloride, ethanol, sulfuric acid, phosphoric acid, Cu, Fe, Mg, Mn, Pb, Sn, Zn, etc.) Harmful factors were extracted from the measurement results of companies with birth certificates. In the second and third stages, carcinogenic and non-carcinogenic risk assessments were performed using the United States Environmental Protection Agency (USEPA) risk assessment guide. In these steps, Monte Carlo simulation method was used to minimize the uncertainty and reach the confidence limit. In the fourth stage, the classification of the health risk level was carried out using a semi-quantitative method according to the method provided by the Singapore Occupational Health Department.

Results: Among the 37 index pollutants identified in all industrial groups, BTEX and Co and Co2 gases were common in all industrial groups. The highest average values that exceeded the occupational exposure limit (OEL) were related to benzene in the group of chemical, acid, petroleum and polymer industries with a value of (1.39 ppm). Among the index pollutants, benzene and ethylbenzene were common in terms of carcinogenic risk in all industrial groups, with the highest carcinogenic risk of benzene in chemical, acid, petroleum and polymer industries with a value of 5.1 x 10-2 and The lowest risk was assigned to the food, pharmaceutical and agricultural industries group with 2.05 x 10-4, and for ethylbenzene, the highest carcinogenic risk was assigned to the metal industry and auto parts group with 1.11 x 10-2. Also, the pollutants benzene, toluene, ethylbenzene and xylene in terms of non-carcinogenic risk were common among all industrial groups, among which, benzene with values of 1.42x10+2 and ethylbenzene with values of 3.90x10+1 in Chemical, acid, petroleum and polymer industries and xylene with 1.64 x 10+2 in metal industries and auto parts group had the highest non-carcinogenic risk values. In the semi-quantitative risk assessment, benzene was rated very high in the chemical, acid, petroleum, and polymer industries and high in the steel, metal, and auto parts, electrical, household, utility, and construction, textile, wood, paper, and cardboard industrial groups. and the cardboard was assigned to itself and also a very high rank was given to the chrome pollutant in the industrial group of steel, metal and Auto parts. Conclusion: The results of the present study from the evaluations carried out in different industrial groups showed that the risk of carcinogenic and non-carcinogenic substances exists in all industrial groups and is not limited to certain industrial groups, and this is due to the use of chemical substances, especially BTEXs, which are directly involved in the process. It is used or produced as a result of a series of activities and processes. Among all chemicals available in industrial groups, benzene and ethylbenzene in the group of chemical, acid, oil and polymer industries have the highest carcinogenic risk, and benzene and xylene in the same group have the highest non-carcinogenic risk. Regarding the semi-quantitative risk assessment, benzene among all identified index pollutants with a very high rating in the group of chemical, acid, petroleum and polymer industries has the highest risk rating and in the group of food, pharmaceutical and agricultural industries with the lowest rating assigned the risk and the rest of the chemicals assigned a medium to low risk rating. In addition, the comparison of risk coefficients and risk ratings obtained in both methods, that is, with the presence of pollutant concentration values with monitoring and the absence of concentration values and without monitoring with each other, confirmed the closeness between the two methods.