Investigation of seasonal variation and probabilistic risk assessment of BTEX emission in municipal solid waste transfer station

ABSTRACT

The municipal solid waste transfer stations (MSWTSs) affects both the environment and human health. The present study aimed to investigatethe Concentrations of BTEX (benzene, toluene, ethylbenzene and xylene) the important group of VOCs, in the ambient air of municipal solid waste transfer station (MSWT_S) of Hamadan city and to estimate stochastic cancer and non-cancer risk for inhalation exposure to BTEX compounds by Crystal Ball software. The average produced amount of solid waste in Hamadan in 2109 has been estimated to be over 150,000 tons. The solid waste mostly consisted of a complex mixture containing kitchen/food waste (56.85%), consumed plastics (11.33%), paper (2.88%), glass (1.20%) and other materials (27.74%), which collected from households and commercial areas. The findings revealed that BETX concentration in the ambient air of MSWTS in summer is higher as compared to the spring season. The 95% percentile lifetime cancer risk (LCR) value for benzene was estimated to be 8 × 10⁻⁴, which is higher than the recommended standards (10⁻⁶). The obtained 95% percentile hazard quotient (HQ) value for xylene was found to be higher than the suggested value of 1. Also, the total cumulative value of the 95^th percentile HQs for (toluene, ethylbenzene and xylene) TEX was obtained to be about 3.39, which is higher than the acceptable value of HQ. The results of sensitivity analysis for LCR of benzene and HQs of TEX disclosed that the parameter of pollutants concentration has the highest effect on risk’s variance. According to the values of cancer and non-cancer risk assessment, that were higher than safe levels and the major contribution of pollutant concentration in sensitivity analysis, it is concluded that the implementation and development of technical and engineering control measures must be regarded as an essential target to reduce workers exposure to the pollutants and to decrease the concentration of the pollutant in the ambient air of MSWTS.

KEYWORDS:

• Municipal solid wastes
• transfer station
• BTEX
• probabilistic risk assessment
• Monte-Carlo simulation

Acknowledgments

This study was a Ph.D. thesis in Environmental health engineering and was conducted with the approval of Hamadan University of Medical Sciences and Health Services, Medical Ethics Committee, Code: IR.UMSHA.REC.1398.512, Grant No. 9807235430. As a joint research study, the authors would like to thanks the Institute for Environmental Research, Tehran University of Medical Sciences for financial support of this research study as Grant number 48964.Thanks are owed to the Department of Environmental Health Engineering, Hamadan University of Medical Sciences, for their help in conducting this study.

Disclosure statement

No potential conflict of interest was reported by the author(s).

Additional information

Funding

This work was supported by the Hamadan University of Medical Sciences [9807235430]; Tehran University of Medical Sciences and Health Services [48964].