The great heterogeneity in distribution and composition of soil
pollution in the landfill described in this work underlie the complex
problem that has to be faced when characterizing and studying
remediation strategies. There are a number of areas throughout this
landfill with a high concentration of heavy metals and organic
compounds belonging to all analyzed families.
Yellow lupin (Lupinus luteus L.) was not affected by increasing
concentrations of BaP (dangerous organic compound and
frequently detected in soils of this landfill). However, its growth decreased when exposed to landfill soils, even in those with the
lowest degree of metal and organic pollution. This is the first time
that a phytoremediation study in landfills of Mediterranean environments
has taken endophytic bacteria into account. The preliminary
study of this technique produced good results, as we
isolated endophytes from lupin roots and shoots grown in BaP
polluted substrate. However, it was not possible to find them in the
shoots of lupin grown in landfill soils due to the poor toxicityinduced
condition of leaf tissue. They were, however, isolated
from roots and soils, even from those most polluted by heavy
metals and organic compounds. The initial results with these isolated
strains indicated that one of them has a high capacity for
improving plant growth. Furthermore, nine strains grew in media
with organic pollutants as the sole source of carbon.
The strains with plant-growth promoting potential and those
with organic compound degrading potential will be tested in detail
to discover their real phytoremediation capacity and the possibility
of using them in field experiments. Future research must consider
real landfill conditions: very high degree of heterogeneity in
contaminant concentration, even at sites very close to one another;
great variety of edaphic factors and different environments within
the site (slopes, flat areas and discharge areas), native plant and
microorganism communities that vary greatly based on the latter
factors and on which the establishment of other interesting species
for phytoremediation (herbs and bacteria) will depend. This great
variety in abiotic and biotic factors at a given site must be taken into
account if phytoremediation studies are to be successful