permaculture

[George Anna Clark <esac@laneta.apc.org>]

from page 15 of Guidelines on the Use of Urine and Faeces in Crop 
Production by ECOSANRES
Håkan Jönsson, Swedish University of Agricultural Sciences – SLU
Anna Richert Stintzing, VERNA Ecology, Inc
Björn Vinnerås, Swedish University of Agricultural Sciences – SLU
Eva Salomon, The Swedish Institute of Agricultural and Environmental 
Engineering (JTI)

full document at 
http://www.ecosanres.org/pdf_files/ESR_Publications_2004/ESR2web.pdf

A large proportion of the hormones produced by our bodies and the 
pharmaceuticals that we
consume are excreted with the urine, but it is reasonable to believe 
that the risk for negative
effects on the quantity or quality of crops is negligible. All mammals 
produce hormones and,
during the course of evolution, these have long been excreted in 
terrestrial environments.
Thus, the vegetation and soil microbes are adapted to, and can degrade, 
these hormones.
Furthermore, the amount of hormones in manure from domestic animals is 
far larger than the
amount found in human urine. Thus, even though theoretical estimations 
based on tests with
fish have indicated a risk of ecotoxicity from oestradiol 
(Ambjerg-Nielsen et al., 2004) when
applying urine, both fertilizer experiments and evolutionary history 
strongly indicate that there
is no real risk.

By far the majority of all pharmaceutical substances are derived from 
nature, even if many
are synthetically produced, and they are thus found and degraded in 
natural environments with
a diverse microbial activity. This has been verified in ordinary 
wastewater treatment plants,
where the degradation of pharmaceutical substances improved when the 
retention time was
prolonged from a number of hours to a number of days. Urine and faecal 
fertilizers are mixed
into the active topsoil, which has a microbial community just as diverse 
and active as that in
wastewater treatment plants, and the substances are retained for months 
in the topsoil. This
means that there is plenty of time for the microbes to degrade any 
pharmaceutical substances
and that risks associated with them are small.

Concerning both hormones and pharmaceutical substances, it thus seems 
far better to recycle
urine and faeces to arable land than to flush them into recipient 
waters. Since the aquatic
systems have never before been exposed to mammal hormones in large 
quantities, it is not
surprising that the sex development of fish and reptiles is disturbed 
when they are exposed to
wastewater effluent. Furthermore, the retention time of the wastewater 
in the treatment plants
is far too short for many pharmaceutical substances to degrade and 
recipient waters are also
usually connected to water sources. Thus, it is not surprising that 
pharmaceutical substances
have been detected for decades, not only in e.g. the recipient waters of 
Berlin but also in the
groundwater, which is Berlin’s source of drinking water (Herberer et 
al., 1998).
Guidelines on the Use of Urine and Faeces in Crop Production
9
There are many indications that the possible risk from pharmaceutical 
substances in the
agricultural system is small and far smaller than the risks associated 
with the present system.
One such indication is that in many countries the human consumption of 
pharmaceuticals
is small compared to that by domestic animals, as in most countries most 
commercial feeds
contain antibiotic substances, added as growth promoters. Furthermore, 
the human use
of pharmaceutical substances is small compared to the amount of 
pesticides (insecticides,
fungicides, bactericides and herbicides) used in agriculture, which are 
just as biologically
active as pharmaceutical substances.