Environmental Engineering Reference
In-Depth Information
the soil, while in control and lower concentrations of crude oil, the soil might have
lost its moisture due to fast evaporation of water. Soil moisture is one of the most
important elements for growth and reproduction of microorganisms (Nicolotti and
Egli
1998
; Al-Mailem et al.
2010
; Ayu et al.
2011
). In all vegetated samples the
microbial population was higher than that in non-vegetated samples suggesting that
in rhizosphere area, the microbial population of the soil was increased. Previous
reports also indicated the increase of microbial number in the vegetated contami-
nated soil (Anderson et al.
1993
; Barrutia et al.
2011
; Kathi and Khan
2011
; Maq-
bool et al.
2013
). The reduction of crude oil in vegetated and non-vegetated soils
showed that in all vegetated samples the crude oil reduction was higher than that in
the non-vegetated samples suggesting that plant and its root in the soil can enhance
biodegradation of oil contamination in soil (Brandt et al.
2002
; White Jr et al.
2006
;
Shahriari et al.
2007
).
5 Conclusion
In conclusion, light crude oil either in low or high concentration (1-10 %) contains
toxic compounds that can prevent normal growth and germination of alfalfa in
soil. It can reduce the plant biomass, early chlorosis and decrease the length of
root and shoot. These damages were very significant in treated samples in com-
parison to control. Our results showed that
Medicago sativa
did not biodegrade
crude oil from the soil and had not enough potential for phytoremediation of oil-
contaminated soil.
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