Occupational Exposure of Diesel Station Workers to BTEX Compounds at a Bus Depot

Abstract

Diesel fuel is known to emit pollutants that have a negative impact on environmental and human health. In developing countries like South Africa, attendants are employed to pump fuel for customers at service stations. Attendants refuel vehicles with various octane unleaded fuel, lead-replacement petrol and diesel fuel, on a daily basis. Attendants are at risk to adverse health effects associated with the inhalation of volatile organic compounds released from these fuels. The pollutants released include benzene, toluene, ethylbenzene and xylenes (BTEX), which are significant due to their high level of toxicity. In this study, a risk assessment of BTEX was conducted at a diesel service station for public buses. Using Radiello passive samplers, it was found that benzene concentrations were above recommended international standards. Due to poor ventilation and high exposure duration, the average benzene concentration over the sampling campaign exceeded the US Environmental Protection Agency’s chronic inhalation exposure reference concentration. Lifetime cancer risk estimation showed that on average there is a 3.78 × 10−4 cancer risk, corresponding to an average chronic daily intake of 1.38 × 10−3 mg/kg/day of benzene exposure. Additionally, there were incidences where individuals were at potential hazard risk of benzene and toluene that may pose non-carcinogenic effects to employees.

Characteristics and health effects of BTEX in a hot spot for urban pollution

“…The maximum and minimum concentrations for mornings and evenings were 55.28±5.35μg/m 3 for B and 4.16±0.30μg/m 3 for T in the morning and 56.58±5.76μg/m 3 for benzene and 3.99±0.28μg/m 3 for ethylben-zene in the evening, respectively. These findings are opposite of previous studies since benzene was the most abundant as compared to other components of BTEX in ambient air (Cerón-Bretón et al, 2015; Mohamed et al, 2002; Moolla et al, 2015; Mosaddegh Mehrjerdi et al, 2014; Srivastava et al, 2006). The mean values of benzene observed by Moolla et al (2015) (South Africa), Hazrati et al (2016a, 2016b) (Ardabil, Iran), Mosaddegh Mehrjerdi et al (2014) (Yazd, Iran), Mohamed et al (2002) (United States), Srivastava et al (2006) (Mumbai, India), and Cerón-Bretón et al (2015) (Monterrey, Mexico) were, 313.16, 1690, 1932, 18.94, 539.95, and 55.24μg/m 3 , respectively (Cerón-Bretón et al, 2015; Hazrati et al, 2016b; Mohamed et al, 2002; Moolla et al, 2015; Mosaddegh Mehrjerdi et al, 2014; Srivastava et al, 2006).…”

“…HQ >1 indicates that the potential risk may be important, while HQ values less than and equal to one indicate is a more acceptable levek as the dose level is lower than the RfC (Demirel et al, 2014; Miri et al, 2016; Moolla et al, 2015; Tunsaringkarn et al, 2012; Zhang et al, 2012). For computing the chronic daily intake, the mean concentrations of BTEX were used.…”

“…For computing the chronic daily intake, the mean concentrations of BTEX were used. The cancer slope factor for benzene is 0.029mg/kg-day (EPA, 1999; Moolla et al, 2015) and RfD for benzene, toluene, xylenes, and ethylbenzene were 0.03, 5, 0.01, and 1mg/kg-day, respectively (EPA, 1999; Moolla et al, 2015). It should be noted that the LTCR for other BTEX species such as xylenes, toluene and ethylbenzene (TEX) cannot be calculated since there are no cancer slope factors for these pollutants (Miri et al, 2016; Moolla et al, 2015).…”

“…In terms of health effects, benzene is categorized as carcinogen, ethylbenzene is recognized as a potential carcinogen, while toluene and xylene are classified as Group D carcinogens or non-carcinogenic (Cancer, 2002; Demirel et al, 2014; Li et al, 2009; Tunsaringkarn et al, 2012; Von Burg, 1993). Furthermore, benzene impacts blood production, the lymphatic system, and the central nervous system (Correa et al, 2012; Duarte-Davidson et al, 2001; Moolla et al, 2015), while toluene impacts the reproductive and central nervous systems (Chen et al, 2011; Correa et al, 2012; Duarte-Davidson et al, 2001; Kalenge et al, 2013; Moolla et al, 2015; Tunsaringkarn et al, 2012). With regard to atmospheric chemistry, photochemical reactions of BTEX pollutants can generate secondary pollutants, such as ozone and secondary aerosol via gas-to-particle conversion processes (Alghamdi et al, 2014; Bell, 2006; Crosbie et al, 2014; Demirel et al, 2014; Han et al, 2005; Kourtidis et al, 2002; Marć et al, 2014; Ng et al, 2007; Saxena and Ghosh, 2012; Sorooshian et al, 2007; Srivastava et al, 2006; Zhao et al, 2004).…”

The Influence of Btex Landfill Gas Emissions: A Case Study of Residents in Roodepoort, Gauteng, South Africa

“…The level of toxic effect associated with BTEX is globally well known, yet, data for South Africa is limited to a few studies (for example: Lourens et al [8], Moolla et al [9], Moolla et al [17], Moolla et al [18]). Moreover, there is little legislation regulating BTEX emissions into the atmosphere in South Africa (DEA [19]).…”