Geoscience Reference
In-Depth Information
industry remained unquestioned until the 1990s following the Bovine Spongiform
Encephalopathy crisis.
39
Issues surrounding fertilizers also evolved.
40
Beginning in the 1850s, based on
the well established role of phosphorus in plant growth (recognized as early as the
1840s), there was a frantic world-wide search for fossil phosphates to supply a need
not
lled by bones. Animal bones were no longer needed for phosphorus fertil-
ization following the discovery of large deposits in North Africa and the expansion
of mines in the United States at the beginning of the 20th century.
41
Furthermore,
during the last 3 decades of the 19th century, sulfate of ammonia became essential
for nitrogen fertilization; it was increasingly extracted from ammoniated water
during the manufacture of town gas and later from large industrial coking plants.
42
At the same time, imports of sodium nitrate from South America into Europe and
the United States soared. The growing concern that this latter supply would soon
be depleted
43
turned the search towards the largest known reservoir of nitrogen: air
(it contains 80 % nitrogen). The Haber
Bosch process,
44
developed on the eve of
the First World War, appeared to provide an in
-
nite amount of nitrogen for agri-
culture and the war (it was also used in the manufacture of explosives). With a
growing trend to trust mineral fertilizers over organic ones, these new nitrogen
sources competed with urban fertilizers and more generally with those from recy-
cled materials. In fact, this competition became
ercer as urban growth loosened the
link between city and agriculture.
7.4.2 New Methods of Recovery
In cities that had based their waste management on recycling, these changes put into
question the entire economy and management of urban excreta that had been, until
then, a source of tax revenue or, at the very least, of municipal savings. The crisis
was particularly severe as the issues of recycling and of salubrity, which had for a
long time seemed convergent, con
icted with increasing frequency. Hygienists
severely criticized the act of dumping refuse on streets and, in a few cities from the
1860s, it became necessary to use boxes or refuse bags (Lyons in 1855, Paris in
1883, Saint-Petersburg).
45
This made scavenging more dif
cult and less lucrative as
mixed materials took on an altered quality.
46
The gradual disappearance of animals
39
See for instance: van Zwanenburg and Millstone (
2005
).
40
Wines, op. cit.
41
Matignon (
1931
).
42
Ibid.
43
See for instance: Crookes (
1917
).
44
Smil (
2001
).
45
Jugie (
1993
).
46
Fontaine (
1903
).
