Abstract

Ambient air pollution is a major cause of various diseases which accounts for an estimated 4.2 million deaths per year globally. During the recent decade’s volatile organic compounds such as benzene, toluene, and xylene gained interest in the field of indoor and outdoor air quality. These are responsible for a numerous adverse health effects like asthma, dizziness, fatigue, eye, nose, and throat irritation. Thus, an investigation of ambient benzene, toluene, and xylene (BTX) was conducted at metropolitan (municipal) and bucolic sites of Gorakhpur for a span of one year to determine the contagion levels. Sampling and analysis of BTX were performed using a methodology based on NIOSH method 1501. BTX were sampled by drawing air through activated coconut shell charcoal tubes, using a low-flow SKC Model 220 sampling pump at the flow rate of 250ml/min for 20-24hrs. The air suction rate was verified every week using calibrated rotameters with an accuracy of ±1%. The samples were extracted with carbon disulphide by occasional agitation and the aromatic fraction was subjected to GC-FID.

Total mean concentration of BTX was 32.19µg/m³ from all the samples and the total range was from 4.3µg/m³ to 54.7µg/m³ with the median of 26.3µg/m³. The maximum levels of total BTX were found to be 40.5µg/m³ in winters, followed by 29.6µg/m³ in summer and 26.3µg/m³ in monsoon season. The average BTX concentration was highest at bucolic site (19.1µg/m³) followed by municipal site (8.7µg/m³). At both the sites, maximum B/T ratio was found in winter season whereas the X/B ratio was found to be lowest. Toluene against benzene plot shows R² value of 0.92 and 0.94 at municipal and bucolic sites, respectively. At both the sites, the estimated integrated lifetime cancer risk (ILTCR) for benzene exceeded the threshold value of 1E-06 whereas the individual hazard quotients (HQ) for BTX did not exceed unity at any of the sites.

Keywords: BTX; Carcinogenic/Non-carcinogenic risk; Municipal and bucolic locations; Terai Belt

Abbreviations: HQ: Hazard Quotients; ILTCR: Integrated Life-Time Cancer Risk; VOC: Volatile Organic Compounds; RAIS: Risk Assessment Information System; HQ: Hazard Quotient; HI: Hazard Index