Occupational health risk assessment of benzene and toluene at a landfill site in Johannesburg, South Africa

Abstract

In developing countries land-filling is the most common form of waste management that is practiced. Landfills are known to be anthropogenic sources of air pollutants that have a negative impact on both environmental and human health. People who work on landfill sites are particularly at risk of adverse health effects associated with the inhalation of hazardous air pollutants (HAPs), such as volatile organic compounds (VOCs). Although VOCs only make up between 0.5% and 1% of total landfill gas, they are important due to the high level of toxicity associated with them. Regular air quality monitoring and hazard risk assessments provide important information that can be used in an effort to protect the health and safety of people working in a landfill environment. This is especially important within a developing context as relevant information is limited. In this study an occupational health risk assessment of benzene and toluene was conducted at a landfill in Johannesburg, South Africa. Applying an approach of modelling (using LandGEM) results indicated a significant increase in emission rates over a 90 year period. In addition, ambient air concentrations of BTEX, 100 meters from the landfill, were found to be unacceptable by US EPA air quality recommended standards. Additionally, cancer risk and hazard index calculations of benzene and toluene, of employees on-site, indicated that occupational exposures were above US EPA recommended standards. Thus, it was shown that employees were significantly at risk to adverse health effects associated with inhalation exposure to these HAPs.

Risk Assessment of BTEX Concentration from Combustion of Coal in a Controlled Laboratory Environment

“…The ethylbenzene concentration measured in our study was 2 folds higher than the concentration reported by (80). Toluene, ethyl benzene and xylenes also present several health effects even at lower concentrations (85)(86)(87). determined 1.2 E -4 and 1.1 E -4 respectively.…”

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

“…The winter period was chosen as a stable atmosphere and lower temperatures promote BTEX accumulation within the boundary layer (Kim and Kim [27]). In addition, given that this is the dry season, it reduced the risk of sampling disturbance by precipitation (Moolla et al [9], Moolla et al [17]). Each sampler was placed at a height of 1.5 m above the ground surface.…”

“…The local terrain also has more of an effect in winter, as the mixing height for pollutants is reduced from the high pressure cell over South Africa's interior (Moolla et al [9], Tyson and Preston-Whyte [32]). This causes pollutants to accumulate as opposed to summer when pollutants are less restricted by vertical dispersion (Tyson and Preston-Whyte [32]).…”

“…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]).…”

“…benzene, toluene, ethylbenzene and xylenes), specifically, account for 20-40% of urban VOCs (Zalel and Broday [4]). The dominant sources of urban BTEX emissions range from vehicular traffic emissions (Gallego et al [5]), building renovations (Huang et al [6]), vaporization of fuel (Edokpolo et al [7]), coal-fired power stations (Lourens et al [8]) and municipal solid waste (MSW) landfill sites (Moolla et al [9]). Of these, vehicle emissions from road traffic are reported as the most common urban air BTEX emissions (Terrés et al [10]).…”