Environmental Engineering Reference
In-Depth Information
Table 2.7 Lead and zinc concentrations in survey locations in United Kingdom (geometric means,
mg kg 1 )
All study locations
in U.K.
Mining villages
Location
Depth (cm)
London districts
Lead
Garden soils
0
5
654
5,610
266
Vegetable plot soil 0-15
571
8,730
270
Public garden soil
0-5
294
3,030
185
Zinc
Garden soils
0-5
424
9,340
278
Vegetable plot soil 0-15
522
8,750
321
Public garden soil
0-5
183
none collected
180
Derbyshire (Pb), Shipham (Zn)
Bullock and Gregory ( 1991 )
Accordingly, in different locations it has been found that the contaminants show
a differentiation between urban and suburban areas. In particular towns in the USA,
the top soils of urban agglomerations reveal higher contaminant concentrations than
in the periphery of these locations (Fig. 2.11 ) (Craul 1992 ). Where the land surface
is sealed, the contaminant concentrations are able to be lower than in fallow or veg-
etated areas, because dust was swept away or blown away by wind in dry conditions
(Prokofieva and Gubankov 2000 ).
It should be taken into account that the material used for sealing purposes, in
particular the load-bearing sub-base, is able to consist of problematical material
causing subsoil contamination, if weathering processes are going to continue. In the
two French cities La Teste and Le Mans, however, no soil contamination under-
neath the road was found in spite of their construction using municipal solid waste
incinerator bottom ash, as the alkaline pH value had strongly reduced heavy metal
solubility (Francois 2000 ).
400
350
300
Des Moines
Fitchburg
Lake Charles
Pittsburgh
Reading
250
200
150
100
50
0
urban
suburban
Fig. 2.11 Pb concentrations (mg kg 1 ) in lawn topsoils of five U.S. towns depending on urban
and suburban locations (Craul 1992 )
 
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