Environmental Engineering Reference
In-Depth Information
Results
The highest values of Pt, Pd and Rh are found in samples taken from the main
A6187 road (sites F and I) with maximum values of 97 ppb Pt, 305 ppb Pd and 33
ppb Rh. The lowest values are located in low traffic flow residential areas on minor
roads up slope of the main road in the northwest of Hathersage (sample sites A-E).
Intermediate values of Pt, Pd and Rh are located in residential areas, with higher
traffic flow, both down slope of the main road near community buildings including
a swimming pool and railway station (sites G, H and K) and north east of the main
road in front of the school (site J).
The distributions of Au, Ru and Ir are different from that of Pt, Pd and Rh (Fig.
2
).
Highest Au values occur outside the school with a maximum value of 144 ppb,
in residential areas at sites D, G and J, and not on the main road at sites F or I
(Table
1
). Medium Au values occur in residential areas at sites A and H. Highest
Ru values occur outside the school entrance, on one of the main road site I and in
a residential area at site H. Ir concentrations are low, being detected only in the
winter of 2005 at the same localities as the highest Ru values, on the main road at
site I and outside the school at site J. The maximum Ru value is 22 ppb. Os was
only detected at 2 ppb at one site.
Average values for the three sets of road dust data collected in the winter of
2005, summer of 2006 and winter of 2006 for Pt, Pd, Rh and Au are plotted versus
traffic flow and show that Pd and Rh, and to a lesser extent Pt concentrations,
increase with traffic flow but that this is not the case for Au (Fig.
3a
-
d
).
Gully samples consistently contain lower PGE and Au values than the surface
road dust at each site and gully samples with higher PGE and Au concentrations are
a
b
600
600
500
500
400
400
300
300
200
200
100
100
0
0
0 0 0 040 0 0 0 0
Pt
0
50
100
150
200
250
Pd
c
d
600
600
500
500
400
400
300
300
200
200
100
100
0
0
0
5
10
15
20
25
30
0
10
20
30
40
50
60
Rh
Au
Fig. 3
(
a
)-(
d
) are graphs of Pt, Pd, Rh and Au, respectively, versus traffic flow
