Abstract
Enclosed underground excavation worksite has an environment with poor ventilation and exposure to hazardous substances from diesel engine exhaust and construction materials. The objective of this study was to evaluate the exposure level of elemental carbon (EC), organic carbon (OC), total carbon (TC), polycyclic aromatic hydrocarbons (PAHs), dust and crystalline silica (CS) during underground excavation work for top down construction buildings. Active local air sampling for EC, OC, and TC (n = 105), PAHs (n = 50), dust (n = 34) and CS (n = 34) was conducted from inside and outside the excavator at underground excavation workshop in four different construction sites. EC, OC, TC and CS were sampled with each respirable and total particulates. EC, OC, and TC were collected on quartz-filter and analyzed using the thermal optical transmittance method. PAHs was collected on polytetrafluorethylene filter with XAD-2 and analyzed using liquid chromatography with fluorescence detector. CS and particulates were collected on poly vinyl chloride filter and analyzed using fourier-transform infrared spectroscopy. The geometric mean of respirable EC, OC, TC, total PAHs, respirable dust and respirable CS were 8.69 μg/m3, 34.32 μg/m3, 44.96 μg/m3, 6.818 μg/m3 0.13 mg/m3 and 0.02 mg/m3 from inside the excavator and 33.20 μg/m3, 46.53 μg/m3, 78.21 μg/m3, 3.934 μg/m3, 0.9 mg/m3 and 0.08 mg/m3 from outside the excavator (underground excavation workshop), respectively. The EC and RCS concentration from outside the excavator is significantly higher than that of inside the excavator (p<0.01). The worksite with rock ground, higher vehicle density, blasting and enclosed environments had higher exposure to EC than other sites (p<0.05). There was no significant difference of EC concentration between total and respirable particulates. In top down construction sites, EC concentrations during underground excavation work exceeded recommended exposure limits as 20 μg/m3, accounted for about 50% of the total sample, and the level of concentration of RCS exceeded 1.5 times of occupational exposure limit, 0.05 mg/m3. Efforts are needed to minimize exposure to diesel engine exhaust and silica in underground excavation sites. Management of diesel engine vehicle, supply of fresh air and ventilation and introducing water facilities to create wet environment in underground worksites are strongly suggested.
Highlights
Crowded urban areas in Asia have experienced a recent increase in the number of construction sites that employ top-down excavation methods [1]
The workers engaged in excavation are exposed to diesel engine exhaust (DEE) from excavators and trucks, dust emitted from rock excavation, respirable crystalline silica (RCS), and other fumes and particulate matter
In 2001, the American Conference of Governmental Industrial Hygienists (ACGIH1) introduced the ‘Notice of Intended Changes (NIC)’ of 20 μg/m3 for the concentration of elemental carbon (EC) and canceled it later in 2003 [35], because it exceeded the level of chronic exposure to DEE of 5 μg/m3 set by the Office of Environmental Health Hazard Assessment (OEHHA), California, USA [36] by 4 times
Summary
Crowded urban areas in Asia have experienced a recent increase in the number of construction sites that employ top-down excavation methods [1]. Previous studies have reported the concentration of RCS in construction sites based on typical occupations of tunnel construction worker [4,5,6], cement mason and concrete finisher [5,6,7,8], and building demolition [5, 9,10,11]. The concentration of DEE in construction sites were reported for tunnel [4, 12, 13] and highway [14]. The concentration levels and workers’ exposure to contaminants in tunnel and highway construction have been reported by many researchers, its evaluation for excavation works in top-down constructions is still missing
Sign-in/Register to view highlights & summary 
Published Version (
Free)
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
