H. Kivisto et al., BIOLOGICAL MONITORING OF EXPOSURE TO BENZENE IN THE PRODUCTION OF BENZENE AND IN A COKERY, Science of the total environment, 199(1-2), 1997, pp. 49-63
The purpose of this study was to compare different biological methods
in current use to assess benzene exposure. The methods involved in the
study were: benzene in blood, urine and exhaled air, and the urinary
metabolites t,t-muconic acid (MA) and S-phenylmercapturic acid (S-PMA)
. Blood, urine and exhaled air samples were collected from workers in
a benzene plant (pure benzene exposure) and cokery (mixed exposure, e.
g. polycyclic aromatic hydrocarbons - PAHs) in an Estonian shale oil p
etrochemical plant. The benzene in these samples was analysed with a h
ead-space gas chromatograph, and the metabolites MA and S-PMA with a l
iquid chromatograph using methods developed from published procedures.
Some of the values measured in the Estonian shale oil area were high
in comparison with those published during the last few years, whereas
the values measured in the control group did not show any exposure to
benzene except in the smokers group. The highest median exposure was i
n the benzene factory, 0.9 cm(3)/m(3) TWA (2.9 mg/m(3)) and the highes
t individual value was 15 cm(3)/m(3) TWA (49 mg/m(3)). All biological
measurements in this study gave the same assessment about exposure to
benzene and correlated highly significantly with each other and with t
he air measurements (r = 0.8 or more). In the benzene factory the corr
elation was good even when calculated from samples with air concentrat
ion < 1 cm(3)/m(3) (3.2 mg/m(3)) in the case of blood benzene and urin
ary MA. However, for S-PMA it was weak (r = 0.4) and for benzene in ur
ine and exhaled air it did not exist any more. In the cokery, with mix
ed exposure, the correlation at low levels was weaker even for blood b
enzene and urinary MA (r = 0.6). According to the results in the benze
ne factory the exposure to pure benzene at the level 1 cm(3)/m(3) (3.2
5 mg/m(3)) TWA gave: the blood benzene value about 110 nmol/l (8.6 mu
g/l), MA 23 mu mol/l (3.3 mu g/l) or 2.0 mg/g creatinine, S-PMA 58 mu
g/g creatinine or 0.4 mu mol/l (95.7 mu g/l), benzene in urine 499 nmo
l/l (39 mu g/l), and benzene in the exhaled air 2.8 nmol/l (0.2 mu g/l
). In general, the measurement of benzene in blood and in exhaled air,
as well as benzene and its metabolites MA and S-PMA in urine, all gav
e similar results. However, at low exposure level (<1 cm(3)/m(3)) the
most reliable analyses were MA in urine and benzene in blood. (C) 1997
Elsevier Science B.V.