Environmental Engineering Reference
In-Depth Information
450
400
350
300
250
200
150
100
50
0
0
1
2
3
4
5
6
7
8
9 11 12 13 14 15 16 17 18 19 20 21
site no.
Fig. 2.12
Pb river sediment concentrations (mg kg
−
1
) in the heavily industrialized area of Pernik,
south of Sofia, Bulgaria (Meuser et al
2008
)
Except for atmospheric reasons, some soil contamination is able to be explained
by geogenic causes in the line of background values. The size of the geologically
caused soil contamination depends on the geological formation and ranges conse-
quently from small to large areas.
In contrast, soil
contamination in alluvial floodplains
generally shows a linear
distribution with distinct lengths and widths. As an example, the Strouma River
in Bulgaria reveals a different contamination status, due to the possible sources of
contamination (Fig.
2.12
) (Meuser et al.
2008
). Discharges located at a steel works
(site No. 3 and 4 of Fig.
2.12
) enhance lead values of the sediments abruptly, a
second peak is visible entering the city centre (sites No. 11, 12, 13 of Fig.
2.12
).
Finally, the agricultural land and wetlands (behind No. 16 of Fig.
2.12
) may reduce
the lead values significantly.
Typical contamination patterns show a systematic relationship with the depth
gradients of contamination. Contamination associated with dust sedimentation
indicates a decreasing tendency with depth. Soils contaminated by parent mate-
rial behave in the opposite direction. Soils influenced by flood and historically
determined contamination generally show several contaminated layers in different
depths.
2.5 Chemical Characteristics with Reference to Contaminated
Sites
The presence of technogenic materials in soils may influence the chemical soil
conditions considerably. Most of the calcium-enriched material is strongly alkaline,
raising the
pH value
of the soil matrix. Construction rubble ranges between pH 6 and
Search WWH ::
Custom Search