Environmental Engineering Reference
In-Depth Information
Space
heating
Building construction/renovation,
and metal corrosion
Natural
soil
and dust
Traffic
Suspended
particul.
matter
Resuspension
Resuspension
Industrial
emissions
Street
dust
Surface creep and saltation
and runoff water
Urban
soil
Runoff
water
Domestic
and comercial
wastewater
Sewage
sludge
Compost application
Urban
sediment
Fig. 4.2
Simplifi ed representation of the urban geochemical cycle.
further concentrated in the compost (up to 50-
70
(or “frustrating” (Charlesworth
et al
. 2000, p. 356)),
with a wide variety of processes impacting on the
physico-chemical characteristics of the particles as
they move around the cascade. Very few relations
were found between the geochemical and geophysi-
cal parameters making up the fi ngerprint of sediment
taken from the individual compartments of the
cascade.
Urban geochemistry has established that the urban
environment is complex, subject to a variety of char-
acteristic processes and impacts that lead to poten-
tially polluted material being deposited onto soils,
roads, and streets and subsequently transported in
the aquatic and atmospheric spheres.
g g
−1
), most likely due to the loss of mass during
fermentation in the piles of maturing sewage sludge.
The application of this compost on urban soil re-
introduces silver, resulting in median concentrations
of this element nearly fi ve times higher in compost
amended soils than in non-amended urban soils.
Data published by De Miguel
et al
. (2005) strongly
suggest that not all the silver that enters the urban
water system is confi ned in sewage sludge to re-enter
the urban cycle. Concentrations of up to 16
μ
−
1
and a strong association with typically anthropo-
genic elements like Cu, Pb, and Zn in the sediments
of the River Manzanares that runs through Madrid
implies that a fraction of this silver is stored in the
river sediments.
Charlesworth
et al.
(2000) envisaged the urban
particulate environment as a “cascade” whereby
sources included point sources, fl uvial bed sediments
and polluted dusts (see also section 4.2). These were
then transported in water (see Poleto
et al
., this
volume) by suspended sediment in storm sewers,
rivers, and streams, or in the atmosphere and were
then eventually deposited in gully pots or urban
lakes. However, the urban environment is complex
μ
g g
4.5 Future trends and concluding
remarks
Urban geochemistry has rapidly grown in depth and
complexity over the past three decades. The improve-
ment of already existing analytical techniques and
the advent of new ones have greatly widened the
scope of urban geochemical research. The current
routine use of ICP-AES, ICP-MS, and GC-MS has
facilitated previously laborious multi-elemental
