Environmental Engineering Reference
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applied with the plant. Altenaria sp. singly result in a decrease up to 14 % but when
applied with plant, decrease was 50 % and also Rhizoctonia reduced soil pollution
up to 14 % solely, when applied with plant decrease was raised up to 52 %.
Petroleum pollution of soils is a major environmental pollution in many coun-
tries (Klokk 1984 ), Serious risks can occur to the public health and environment
when the soil is polluted by crude oil (Nicolotti and Egli 1998 ). Results of this work
shows that crude oil, in the concentrations presented here (up to 10 %) did not kill
the studied plant species. This is in accordance with the results of an earlier study
by Nicolotti and Egli ( 1998 ), who showed several legumes and graminoids can
flourish on petroleum polluted soils with about 5 % pollution. The crude oil indirect
effects the soil and results in more or less marked reduction in plant growth and bio-
mass (Merkel et al. 2004). Similar findings have been reported for other plant spe-
cies: Festuca rubra and Puccinellia maritime (Baker 1999 ), Trifolium rubra (Klokk
1984 ) and different legumes and grasses (Merkel et al. 2005 ).
Study on fungal species showed that Alternaria, Penicillium and Rhizoctonia
were the common fungi that have been observed in the roots of all studied plants
both in polluted and non-polluted soils. Based on our data, fungal variation in pe-
troleum polluted area was more than non-polluted one (Table 9.1 ). This means that
roots of the plants had more fungi yielded in polluted areas than non-polluted ones,
which is in accordance with the findings of some prior workers (Anderson et al.
1993 ; Hashem 2007 ). It seems that the fungal species use oil compounds as nu-
trients, because petroleum pollution increases fungal growth. Similar results have
been reported by some other researchers (Eggen and Majcherczykb 1998 ; Yateem
et al. 1997 ; Nicolotti and Egli 1998 ; Obuekwe et al. 2005 ; Dritsa et al. 2007 ).
In vitro growth test of fungi showed a species-specific response. Most of studied
fungal strains were capable of growth in 1 % w/w oil pollution and therefore could
be useful for the remediation of light soil pollution. Some fungal species were in-
hibited by high oil concentrations (10 % w/w). These species were Alternaria sp.,
Penicillium sp., and Rhizoctonia sp. , while others actually grew well in oil-contam-
inated media, even at very high concentrations. These are Fusarium acuminatum,
F. equiseti, and F. reticulatum . It seems that crude oil could supply some nutrients
for these fungi and they could prove more effective for oil degradation. Our find-
ings are in accordance with those of other researchers about other fungal species
(Eggen et al. 1998; Yateem et al. 1997 ; Nicolotti and Egli 1998 ; Obuekwe et al. 2005 ;
Dritsa et al. 2007 ).
Bioremediation of a petroleum-contaminated soil is mainly based on biodegra-
dation in the rhizosphere (Frick et al. 1999 ), root-associated fungi are one of the
most important factors. The results of this study propose that above mentioned fun-
gi can be evaluated for the future remediation tests and this is the first report about
their remediation capacity. The data of this study indicates that isolated strains of
Fusarium acuminatum, F. equseti and F. reticulatum may have the potential for
bioremediation of crude oil in highly polluted soils especially in semi-dry regions.
A. retroflexuus abundantly found in the polluted areas when chosen for biore-
mediation test together with its root associated fungi show that the concentrations
of crude oil decreased in the pots containing plant with all fungal strains added.
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