SUITMA 2005 Cairo - Contribution of dust to soil formation in urban and industrial areas
SUITMA 2005 Cairo
| This abstract is about one of the papers of the Properties of unconventional soils theme of the SUITMA 2005 symposium. |
| Wolfgang Burghardt,i | Silke Hoeke.i |
- i - Department of Soil Technology, University Duisburg – Essen, Essen, Germany.
Dust formation in urban areas can be very high and will play in arid and semi arid regions an important role. An example of the city of Hannover, Germany, shows that dust already is of importance for soil formation in humid climate. An accumulation of 5 to 8 cm within 50 years was observed.
As examples in Germany show formation of a new top soil layer by dust deposition. It enables vegetation growth on disadvantageous substrates such as mining spoil with high content of skeleton, substrates of strong acidity or high pollution. The thin colluvial layer meets not the taxonomic criteria for designation as Colluvium. But it changes already fundamental the soil properties as living body.
In urban and industrial areas occur dune and soil cover formation over sealed sites, e.g., middle strips of double lanes or streets of abandoned sites. The soils are designated for the present as Aeroliths. They are in a starting stage of soil formation. Therefore they are lithic soils. They play an important role in the return of nature into cities.
Dust will intrude easily in voids between stones and gravel and fill them up. These soils are Particle Intrusols. They are most common on railway lines and sidings and again enable characteristic vegetation growth.
Dust accumulates in substrates of roof top plantings. Soil development from these substrates will be strongly influenced by dust. Dust will be also incorporated in soils of urban and industrial areas dominated by fine earth material. Mixing calculations by use of grain size distribution and element contents of surface soils indicate dust inputs up to 30% (???) of total soil material. Therefore we must assume the wide spread occurrence of semi – colluvial top soil horizons.
Dust plays also an important role in formation of soils in the slots between pavement stones and cobbles. Dust is laterally transported on the pavement stones and concentrated in the voids of the loose sand filling of the slots. The soils are designated as interval soils or Dialeimmasols. The contribution of dust to the formation of this kind of soils can be more than 40%.
The relationship of dust and soils in urban areas has diverse importance. Dust contributes to the improvement of soils of several sites but can also occur as hazardous fine dust (PM10). Soil can dilute dusts containing hazardous compounds and can be sources of dust.
