Environmental Engineering Reference
In-Depth Information
age concentrations of the same metals in ambient PM using the STN concentrations
in Table 1 . This common dose metric is based on assumptions regarding body
weight, breathing rate, and particle size; the derivation of this metric is more fully
described in the introduction section of this paper. These estimated “animal to
human” ratios were based on the concentration of the specifi c metals in the PM
source in
g metal/g PM mass and using conservative assumptions for the weight
and volume of air breathed per day for an average human, dog, rat, and mouse. In the
majority of the studies reviewed, the results were analyzed using ANOVA with
appropriate after tests (e.g., Bonferroni or Tukey's) for multiple comparisons.
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In Vivo Exposures to Metals in Ambient PM
The seven studies discussed in this section addressed the effects of ambient PM
extracts on cellular and soluble markers of infl ammatory response in BALF. The
studies share common design features in that doses of PM extracts in saline were
directly instilled into the lungs of rats or mice, the animals sacrifi ced at one or more
time intervals post-instillation (e.g., 24 and 96 h), and infl ammatory markers in
BALF examined. The sources of ambient PM, experimental animals, and signifi cant
responses from this group of studies are summarized below. The concentrations of
specifi c metals in the source material (Table 6 ) was readily available for fi ve (Dye
et al. 2001 ; Molinelli et al. 2002 ; Costa and Dreher 1997 ; Gavett et al. 2003 ; Schins
et al. 2004b ) of the studies. In the remaining two studies (Gerlofs-Nijland et al.
2009 ; and Happo et al. 2008 ), the investigators used extracts of ambient PM from
airsheds in Europe that differed with regard to industrial vs. non-industrial sources.
Concentrations of metals in the source material used in many of the studies are pre-
sented in Table 6 and the fi ndings are summarized in Table 7 .
Ambient PM from the Utah Valley
Dye et al. ( 2001 ) conducted a series of three experiments to evaluate the toxicity of
aqueous extracts of TSP from the Utah Valley in 1986, 1987, and 1988 correspond-
ing to the time period of the epidemiology studies published by Pope ( 1989 , 1991 )
to test the hypothesis that the decrease in respiratory illnesses reported in 1987
while an open-hearth steel mill was closed for repairs, as compared to the two adja-
cent years, could have been associated with decreased exposure to the water/acid
soluble fraction of airborne metals. The concentrations (
g metal/g TSP) of transi-
tion metals of interest in the Utah Valley PM samples are presented in Table 6 , along
with concentrations of metals in National Institute of Standards and Technology
(NIST) No. 1648 (St. Louis). On a mass basis, the concentrations of Cu, Zn, Fe, Ni,
and V were much greater in the NIST reference sample than concentrations for
these metals in any of the three Utah Valley TSP samples. Three experiments, using
varying doses of PM extracts in saline, were performed with healthy Sprague
Dawley rats to assess non-specifi c airway responsiveness, BALF indicators of cel-
lular response, and general lung pathology at 24 and 96 h post-instillation. Data
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