Environmental Engineering Reference
In-Depth Information
Isles of Scilly
2.4/24
2.4/24
0.6/6
Big Pool
2.4/24
Porth Hellick
3.0/30
Rural Midlands
12.9/90
12.9/90
7.1/74
Mervale Lake
12.9/90
Seeswood Pool
20/164
Urban Midlands
208/1233
42/133
Pb kg ha
-1
Zn kg ha
-1
183/692
Swanswell Pool
208/1233
Wyken Slough
225/825
0.6/6
Fig. 5.3
Estimated anthropogenic excess loading from atmospheric and catchment sources for six lowland England lakes and
reservoirs: (1) Pb; (2) Zn.
From Foster & Charlesworth (1996).
sites to urban peripheral lakes, then rural and fi nally
to more isolated sites (Fig. 5.3). Urban lakes can
therefore provide a signifi cant sink for contaminated
sediments, and although there are few studies of such
features, Table 5.1b shows the concentrations that
can be found in their bed sediment.
The sediments that do accumulate in urban lake
basins refl ect processes occurring in their catchments
(Schueler & Simpson 2001) and as such can provide
information on the pollution history of their catch-
ments (Charlesworth & Foster 1993; Christopher
et al
. 1993; Graney & Eriksen 2004). In a study of
two urban lakes in Coventry, UK, Charlesworth &
Foster (1993) were able to show the decline in metals
from approximately 1970 to the early 1990s. Such
studies can be applied to health concerns (see, for
example, Christopher
et al
. 1993; Graney & Eriksen
2004;) and management strategies (Charlesworth &
Foster 1991; Rao
et al
. 2004). Although it has been
established that urban sediments are signifi cantly
contaminated, if the trace element concentrations in
the bed sediments of lakes receiving urban runoff are
compared with those impacted by non-ferrous metal
extraction processes (Foster & Charlesworth 1996),
then it is found that urban lake concentrations are a
magnitude lower. There have been very few studies
of natural wetlands that have been subsequently
impacted by urbanization (see Bentivegna
et al
.
2004), although there are many of constructed wet-
lands designed for runoff contaminant mitigation
(see, for example, Lai and Lam 2009). Table 5.1d
includes the concentrations in wetland substrate
