THE WORLD CONFERENCE ON ECOLOGICAL RESTORATION

2005 The World Conference on Ecological Restoration 21
Towards a more safe environment: (4) Disposability of uranium by some clay
sediments in Egypt
Abd-Allah 1 S.M., O.M. El Hussaini 2 , R.M. Mahdy 2
1 Soils Dept., Fac. Agric., Ain Shams Univ. Cairo, Egypt. P.o.Box 68 hadayek shoubra 1124, Cairo, Egypt.
2 Nuclear Materials Authority, Cairo, Egypt
Due to the increase concerns about the environmental pollution problems, it is so important in waste
disposal management to perform an accurate exploration of geological barriers, which must be suitable
for waste materials disposal. Clay sediments play an important role as natural adsorbents to immobilize
heavy and nuclear metals contaminants.For the present study, the clay samples were collected from either
clay exploitation localities or from nearby radioactive mineralization in Egypt. Obtained results indicated
that uranium adsorption and desorption differ importantly in accordance with the source of clay
sediment used. In addition, its adsorption increases by increasing uranium initial concentration. The obtained
data were found to fit of Langmuir equation isotherms. Adsorption maxima (B) for uranium were
high for Abu Tartur bentonite followed by El Hafafit vermiculite and was the least for Kalabsha kaolinite.
However, the binding energy (b) that affects the adsorption process can be arranged in the opposite direction.
Desorption of uranium by HCl, NaOH and tap water show clear ability of the different sediments to
release uranium. This was a function of leaching solution and binding energy. Finally, the changes in the
clay sediments through adsorption and desorption processes were investigated in detailed by I.R spectroscopy.
Keywords: adsorption-desorption, clay sediments, I.R, nuclear, pollution, uranium.
Mycorrhiza: a tool for forest restoration in calcareous soils
Adjoud-Sadadou D., R. Halli-Hargas
Université Mouloud Mammeri de Tizi-Ouzou. Faculté des Sciences biologiques et des Sciences agronomiques. Département de
Biologie. Laboratoire Mycorhizes.BP 17 RP Tizi-Ouzou 15000. Algérie
Toxicity of calcareous soils is well established. This lead to the existence of large stripped and damaged
areas. In this study we suggest to use mycorrhizal seedlings inoculated with suitable calcicole strains of
mycorrhizal fungi in reforestation programs for calcareous soils. The mycorrhizal symbioses are mutualistic
associations between plants and fungi. It has been unequivocally demonstrated that these associations
confer many benefits to the plant and allow their establishment under many unfavourable ecological
conditions. Eucalyptus camaldulensis, a calcifuge species, growing in a patch of calcareous soil in the
north of Algeria was examined for mycorrhizal status. Results revealed that all the trees were mycorrhizal.
Samples of this soil, containing the mycorrhizal fungus symbionts, were taken down to a depth of
25 cm. around the trees and pooled together. Then, it was divided into 2 parts and one of them was sterilized
to eliminate all the soil inoculum. Seedlings belonging to 3 calcifuge Eucalyptus species were germinated
in sterilized peat-perlite mixture (60-40 v/v). After two months of growth, they were transferred
into pots filled with soil sterilized or not. All the seedlings transferred into sterilized soil grew very poorly,
showed leaf clorosis or died. Seedlings transferred into non sterilized soil grew well. Observation of their
root systems revealed typical mycorrhiza, arbuscular mycorrhiza and ectomycorrhiza. It is obvious that
the fungi which formed these mycorrhiza are calcicole strains, allowing seedlings of calcifuge Eucalyptus
species to establish in such a calcareous soil.The information generated by this study should enable the
nursery man to target which mycorrhizal fungi to select as suitable inoculant for calcifuge species in
such calcareous soils.
Keywords: Mycorrhiza. Reforestation. Calcareous soils. Calcifuge plant species.
Restoring Atlantic wet dune slack habitats in an artificial recharge area
Aggenbach 1 C.J.S., P.J. Stuyfzand 1,2 , M. Annema 3 , M.W.A. de Haan 1
1 Water System Management Department, Kiwa Water Research, Nieuwegein, Netherlands
2 Faculty of Earth and Life Sciences, Vrije Universiteit Amsterdam, Netherlands
3 Evides, Ouddorp, Netherlands
In an Atlantic coastal dune area the effects of changes in artificial recharge using river water (AR),
groundwater discharge and management, on wet dune slacks, were studied at 12 locations differing in
AR (stopped, unchanged, increased). Most of these locations were sod cut and grazed, some were also
mown. Plant species composition, groundwater levels, nutrients in standing crop, chemistry of topsoil
and groundwater were monitored for several years. At locations where AR stopped, Cl - , Na + , SO 4 2- levels
in the groundwater dropped and visa versa. At locations with increased AR locally thin rainwater bodies
developed in the topsoil rising dissolution of calcium carbonates. At locations with increased and un-