Environmental Engineering Reference
In-Depth Information
Contaminated land
Soil contamination
Deposits
Industrial plots in use
Heaps
Damaged wastewater tubes
Fills
Flooded areas
Accident sites
Locations influenced by dust sedimentation
Agriculturally used areas (pesticides, manure)
Fig. 2.10
Sources of contaminated sites
•
accident sites with losses of problematical contaminants like mineral oils (leaking
tanks and pipes of garages and petrol stations, accidental oil spills close to roads);
•
agriculturally or horticulturally used sites, with possible application of pesticides
as well as potentially contaminated manures like sewage sludge or composted
municipal solid waste.
Most of the causes may lead to a depth gradient indicating decreasing con-
tamination with increasing soil depth. Soil contamination often does not have
visible features except for e.g. oil phases (accident sites) or artifacts (floodplains).
Apart from the last example, the contamination source is located in the upper
usually humic part of the profile connected with a high contaminant adsorption
potential.
The
atmospherically determined soil contamination
involves both solid particles
(particulate matter) and liquid droplets. In particular, atmospheric dust deposition
plays an important role in districts with heavy traffic. On the one hand, with increas-
ing distance to the road the decrease of deposition is rapid. On the other hand, in
areas with intensive traffic, particularly the city center, an accumulation of dust on
a large scale should be taken into account.
Dust deposition can be responsible for very high heavy metal concentration as
examples in United Kingdom demonstrate (Table
2.7
). The values in agglomerations
like London are higher than in all studied locations of the United Kingdom. Very
large concentrations, however, were found in mining villages, where dust devel-
opment and enhanced geologically based background values have to be combined
(Bullock and Gregory
1991
).
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