Environmental Engineering Reference
In-Depth Information
PM
2.5
concentration or the concentration of any transition metal and changes in
brachial artery diameter, whereas there were signifi cant negative associations for
both the organic and elemental carbon concentrations of the PM
2.5
.
Effects of PM Metals on Indicators of Infl ammation
Two of the six studies reviewed in this section attempted to correlate concentrations
of metals in ambient PM with infl ammatory markers in nasal lavage fl uid (Schins
et al.
2004b
) or to indicators of oxidative DNA damage in blood and urine (Sorensen
et al.
2005
). In the other four studies (Ghio and Devlin
2001
; Ghio
2004
; Lay et al.
1999
; and Schaumann et al.
2004
), particulate extracts and/or metal particles were
instilled into the lungs of volunteers and infl ammatory markers were measured in
bronchiolar lavage fl uid.
In a cross-sectional survey of 67 children living in four areas of Germany that
have different traffi c densities, Schins et al. (
2004a
) tested the utility of measuring
platinum (Pt) in nasal lavage fl uid as a potential biomarker for traffi c related PM
exposure. The authors stated that the four locations had signifi cantly different con-
centrations of PM, NO, NO
2
, CO and Cr, but not Pt or V, although the actual con-
centrations could not be gleaned from the study. Levels of IL-8 and differential cell
counts of neutrophils, eosinophils, monocytes, lymphocytes and epithelial cells
were measured in nasal lavage fl uid from the subjects. Pt was signifi cantly corre-
lated with an increased number of neutrophils and epithelial cells. There was only a
weak association between V and epithelial cell concentration. No other statistically
signifi cant correlations were reported, and no other potential explanations were
offered for differences in cell counts.
Sorensen et al. (
2005
) attempted to correlate ambient PM
2.5
and transition metals
with concentrations of 7-hydro-8-oxy-2
-deoxyguanosine (8-oxodG) as an indica-
tor of oxidative damage in the blood and urine of 49 young, healthy, non-smoking
adults, aged 20-33 years living in central Copenhagen. Summer and winter concen-
trations of transition metals in ambient PM
2.5
are presented in Table
5
. Mixed-model
repeated measures analysis did not reveal statistically signifi cant associations
between the concentrations of 8-oxodG in urine, and water soluble transition metal
concentrations or 8-oxodG levels in lymphocytes. Since it appears that blood and
24-h urine samples were only collected on two occasions for each subject, it is not
possible to determine individual variability in 8-oxodG over time. Other exposures
were not well-accounted for, and there were a relatively small number of subjects
enrolled in the study.
′
Controlled Exposures to Human Volunteers
The four human dosing studies that will be discussed in this section share features
with the rodent intratracheal instillation studies found in the next part of this review.
In the following group of studies, volunteers were exposed to known amounts of the
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