Appendix D - Dossier (PDF) - Tera

date: 20–JUL–2005
5. Toxicity Substance ID: 71–43–2
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Remark: Although ambient exposure to benzene and other VOCs is the
focus of this investigation, no contemporaneous exposure
data were collected over the period of the study. It is also
apparent that while differences in haematological parameters
were present in children from the two regions, there was
little consistency in the magnitude or direction of any of
the reported changes. Temporal instability in data collected
from the control population appeared to be quite marked.
Result: COMMENT: there appeared to be little consistency in
haematological results obtained from exposed and unexposed
children on the three timepoints included in this study.
In samples collected in April 2000, total WBC counts and
absolute lymphocyte counts were significantly lower than
control in 11 yr old children living near the petrochemical
facility, while exposed 8 yr olds showed a significant
decrease in RBC and HgB. Platelet counts were significantly
lower in both exposed age groups at this time.
In July, total WBC, absolute neutraphil– and lymphocyte
counts for 8 yr olds were significantly higher in the
exposed group in comparison to the suburban group. There
were no significant differences between exposed– and
unexposed 11 yr olds at this sampling time.
In October, RBC counts and HgB values were significantly
lower in 8 yr olds from the vicinity of the petrochemical
plant, whereas platelet counts from the exposed group were
higher than those of the controls. There were no significant
differences between exposed– and unexposed 11 yr olds at
this sampling time.
Analysis of CBC data using a generalised linear model
analysis of variance showed that ’region’, ’survey month’,
’model’ were significant independent variables influencing
RBC and platelet counts, while sex and age influencing one
or other of these measures. There was a significant
association between ’region’ or ’age’ and WBC count, while
age was also an independent variable influencing lymphocyte
counts.
There was a strong, statistically significant interaction
between [survey month x region and haematological parameters
assessed in the study.
Source: A.K. Mallett Surrey
Conclusion: The authors conclude that environmental exposure to VOCs
containing low levels of benzene is associated with a higher
prevalence of haematological abnormalities that could serve
as biological markers for medical surveillance. The causal
nature of this association is difficult to substantiate,
however, since no concurrent measures of benzene exposure
were included in the investigation.
27–MAR–2003 (677)
Appendix D: Benzene SIDS Dossier
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