TITLE:
Assessment of BTEX Concentrations in Air Ambient of Gas Stations Using Passive Sampling and the Health Risks for Workers
AUTHORS:
Lícia P. S. Cruz, Lidmary P. Alve, Akácia V. S. Santos, Mabel B. Esteves, Ícaro V. S. Gomes, Luís S. S. Nunes
KEYWORDS:
BTEX, Gas Stations, Passive Sampling, Health Risk
JOURNAL NAME:
Journal of Environmental Protection,
Vol.8 No.1,
January
10,
2017
ABSTRACT: Gas stations are important
emissions source of benzene (C6H6), toluene (C7H8),
ethylbenzene (C8H10), and ortho, meta and para-xylene (C8H10)—better
known by the acronym BTEX. The objective of this study was to determine the
concentrations of BTEX compounds in the ambient air of ten gas stations in the
cities of Salvador and Feira de Santana, Bahia, Brazil and evaluate the health
risks to workers. Passive samplers diffusive of the Radiello?, containing activated
carbon as adsorbent, were used. The samplers were exposed for 8 h and then the
analytes were recovered by chemical desorption with CS2 and determined
by GC-FID. The BTEX concentrations found in the ambient air of gas stations
ranged from 46.72 - 435.43 μg·m?3 for benzene; 25.54 - 342.46 μg·m?3 for toluene, 7.10 - 30.07 μg·m?3 for ethylbenzene, 9.36 - 89.73 μg·m?3 for m, p-xylene and 9.79 -
52.29 μg·m?3 for o-xylene. The
concentrations of toluene, ethylbenzene and xylenes found in gas stations were
lower than the limits recommended by the US NIOSH and NR-15 of the Ministry of
Labour of Brazil; however, it should be considered the risks due to chronic exposure of workers. Benzene
concentrations in three gas stations were above the exposure limit recommended
by NIOSH (3.20 × 102 μg·m?3). Samplings were also held outdoors at 250 m of two gas
stations. The total concentrations of the BTEX compounds were equal to 24.97
and 35.51 μg·m?3,
and benzene concentrations were about 3 - 4 times
higher than the annual pattern of 5.0 μg·m?3 established by Union European, as tolerance limit for
outside areas. These data confirm that the next areas of gas stations are subject to the
effects of volatilization of these compounds. Additionally, the values found in
the 10 gas stations for the cancer risk ranged from 4.06 × 10?5 - 3.78 × 10?4 (mean of 1.82 × 10?4) for workers exposed to benzene for
30 years (acceptable limit equal 1.00 × 10?6). The cancer risk is very high,
because the values found are about 40 - 378
times above the acceptable limit and reinforce the need to adopt urgent measures
to reduce or eliminate exposure of workers to the BTEX compounds. The average
non-cancer
risk to benzene, toluene, ethylbenzene and xylenes was 1.84, 5.76 × 10?3, 4.59 × 10?3 and 1.37 × 10?1, respectively (acceptable limit 1). Only to benzene the
average value of this risk is above 1, showing that workers are likely the adverse effects
health due to exposure to benzene.