LCA Food 2012 in Saint Malo, France! - Manifestations et colloques ...

PARALLEL SESSION 3C: SHEEP AND DAIRY PRODUCTION SYSTEMS 8 th Int. Conference on LCA in the
Agri-Food Sector, 1-4 Oct 2012
of consumed water (removed from watershed through evapo(transpi)ration or incorporation in product), the
this footprint ranged from 12-336 L/kg FPCM. With only 20% of milk produced in irrigated areas, the overall
weighted average amounts to 61 L/kg FPCM.
The potential impacts on human health, ecosystem quality and resource depletion were assessed following
different methodologies (including Maendly et al., 2010, Pfister et al., 2009,van Zelm et al.,
2010,Verones et al., 2010) yet were shown to be negligible overall (< 1%). With regards to water scarcity, it
is only critical in a specific location in the prairies that is not well represented in provincial averages yet still
targets an important concern.
3.3. Ecosystem quality
In this category, potential impacts were highest for aquatic ecotoxicity, eutrophication and land use. In the
first case, it was mainly the result of possible heavy-metal discharges to water associated with energy production
for different life cycle stages. Zinc in mineral feed supplements also contributed. The two other
sources of impact were linked to phosphorus fertilisation and arable land use.
Interestingly, all contributions displayed “ecosensitivity” based on farm location, as a function of geographic
variation in characterisation factors (CFs), for example those for land use (Erreur ! Source du renvoi
introuvable.). The effect is obvious when provincial values calculated using regional-level CFs are
compared to those calculated using national-level CFs (Fig. 4). The regionalised provincial results range
from 3-33 PDF*m 2 *yr (median = 8), while the weighted mean equals 15 PDF*m 2 *yr, illustrating that while
half the provinces are below the median of 8 PDF*m 2 *yr, most milk is produced in areas that are more
ecosensitive, thereby driving up the weighted mean.
Figure 3. Map of regionalised land use characterisation
factors (CFs)
3.4. Human health
330
Figure 4. Provincial distribution of impact on ecosystem
quality using regional-level (“regionalised”)
and national-level (“not regionalised”) characterisation
factors.
Potential effects on human health were modelled with six different impact categories, but only toxicity
was regionalised. While toxicity plays a role in the overall impact (around 7%), ammonia emissions have the
greatest influence (63% of potential impact). Ammonia emissions, from fertilisers, in housing and from manure
storage, are linked to respiratory difficulties. The remainder of impacting substances also falls in the
category of respiratory inorganics, related to fossil-fuel combustion (emissions of NOx, SO2, and hydrocarbons),
electricity production and direct use. Potential toxicity impacts are also due to the heavy metal content
of manure spread on crops not used in feed. Zinc, most notably, bio-accumulates, and excess zinc consumption
(through crops) can interfere with the absorption of other essential minerals (ODS, 2011).