Appendix D - Dossier (PDF) - Tera

date: 20–JUL–2005
5. Toxicity Substance ID: 71–43–2
______________________________________________________________________________
07–JUL–2005 (886)
Remark: Assessment of complete blood count variations among workers
exposed to low levels of benzene.
The effect of benzene on white blood cell and red blood
cell
counts, hemoglobin level, mean corpuscular volume (MCV),
and
platelet count was investigated among workers in a small
petroleum company. The investigated cohort consisted of 105
workers exposed to low levels of benzene between 1967 and
1994. The average level of benzene exposure per year ranged
between 0.14 parts per million and 2.08 parts per million
(8–hour time–weighted average). The mean complete blood
count (CBC) demonstrated values within normal ranges. With
the exception of white blood cells, all other CBC values
were significantly reduced during the follow–up period.
Length of employment was significantly related to the
changes in MCV and platelet counts. The reductions in MCV
were significant only among workers who had been employed
for more than 10 years at this particular company. The
findings of this study suggest that low levels of benzene
may affect CBC values. CBC values may serve as a useful
tool
for biological monitoring for workers with low–level
benzene
exposure.
Additional Comments: The investigators indicated that
there
was no consistent CBC by individual for each year of the
study and that confounding factors such as smoking and
other
non–work related sources were not taken into account since
no control group was used.
Source: EXXON Biomedical Sciences East Millstone, NJ
Reliability: (2) valid with restrictions
07–JUL–2005 (616)
Remark: Effect of benzene, toluene, xylene on the semen quality of
exposed workers.
The effect on semen and sperm quality of workers following
short– and long–term exposure to benzene, toluene, and
xylene was examined. Semen and blood of 24 married workers
exposed to benzene, toluene, and xylene from shoe–making,
spray painting, or paint manufacturing facilities were
collected. Benzene, toluene, and xylene concentrations in
blood and semen were determined a using headspace
chromatographic method. Routine sperm tests were conducted
and acrosin activity detected. Results showed that benzene,
toluene, and xylene were in blood and semen of some
ex–workers in an environment where air concentrations of
benzene, toluene, and xylene exceeded the max. allowable
concentration (MAC). This result was not observed in
control
Appendix D: Benzene SIDS Dossier
– 736/957 –