Environmental Engineering Reference
In-Depth Information
uniform concentration of oil in all plates, the solution was thoroughly mixed with
a magnetic stirrer, right before it was added to the plates. Three concentrations of
Oil/PDA mixture (1, 4, and 10 % w/w) were prepared. Pure PDA was used in con-
trol plates. All dishes were inoculated with 2 mm diameter plugs of fungal mycelia
taken from agar inoculum plates. The dishes were incubated at 25 ± 2 °C in an in-
cubator. Fungal mycelia extension on the plates (colony diameter) was measured
using a measuring tape after 4 days and compared with the control plates.
1.4
Evaluation of Petroleum Removal
A. retroflexua is a petroleum resistant plant, common and native in the studied
petroleum polluted area. It is a dominating species in the area, especially in the
central region of the petroleum polluted sites. Seventy pots were prepared in April
2010 and filled with 2 kg of sterilized soil collected from the Amaranthus growing
area. These were divided in to 16 groups; each group with 5 pots. The groups were
divided as follows; (1) Sterile soil, (2) Sterile soil + Plant, (3) Sterile soil + Alte-
naria , (4) Sterile soil + Altenaria + Plant, (5) Sterile soil + Fusarium acuminatum,
(6) Sterile soil + plant + F. acuminatum , (7) Sterile soil + F. equiseti ., (8) Sterile soil
+ plant + F. equiseti , (9) Sterile soil + F. reticulatum , (10) Sterile soil + Plant + F.
reticulatum , (11) Sterile soil + Penicillium, (12) Sterile soil + Plant + Penicillium ,
(13) Sterile soil + Rhizoctonia , (14) Sterile soil + Plant + Rhizoctonia , (15) Sterile
soil + all the fungi, (16) Sterile soil + Plant + all the fungi.
In the groups which contained the plant, each pot had two seedlings of A. retro-
flexus . All pots were polluted with crude oil at a pollution level 5 % w/w. They were
left under the same conditions in greenhouse at Bu-Ali Sina University. A. retro-
flexus plants were removed and deposited at the end of the growing period. The soil
of experimental and control pots was homogenized separately and kept at 4 °C in a
refrigerator until further evaluation. Concentrations of crude oil were determined in
the soil of experimental and control pots.
1.5
Determination of Total Oil and Grease (TOG)
Soil samples from the experimental and control pots were collected separately. Each
soil sample, without root segments, was homogenized and stored at 4 °C until fur-
ther processing. TOG was analyzed according to the EPA method 9071 A and EPA
Method 3540 B (U.S. EPA 1994 ). Fifteen gram of the soil in two replicates were
acidified with hydrochloric acid to pH = 2 and dehydrated with magnesium sulphate
monohydrate. After 15 min, samples were transferred into paper extraction thimbles
and placed in a soxhlet apparatus. TOG was extracted with dichloromethane for
8 h. The extract was filtered through filter paper (Whatman No. 4) with 1 g sodium
sulphate. The solvent was evaporated with a rotary evaporator and the weight of dry
extract was determined. Percentage of TOG was calculated based on soil dry weight
and compared in the vegetated and non-vegetated areas.
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