International Journal of Marine Science, 2017, Vol.7, No.6, 51-58
52
1 Materials and Methods
West Qurna oil field is located in Basrah city southern Iraq, around 65 km NW of the city of Basrah. Soil samples
were collected seasonally during the period from September 2015 to March 2016 at ten stations in West Qurna-2 oil
field at Basrah city (Figure 1). Samples were warped with aluminum foil then transferred to the laboratory for
analysis.
Figure 1 The study area and sampling stations
Before analysis, soil samples were freeze-dried, ground finely in an agate mortar and sieved through a 62 um
metal (stainless- steel) sieve.
The extraction and cleanup procedure for the determination of petroleum hydrocarbons in the soil was based on
that of Al-Saad (1995). Soil was placed in a pre-extracted cellulose thimble and soxhlet extracted with 150ml
methanol: benzene (1: 1) mixture for 24 hours. At the end of this period, the extract was transferred to a storage
flask and the samples were further extracted with a fresh solvent. The combined extracts were reduced in volume
to 10ml in a rotary evaporator. It was then saponified for 2 hours with a solution of 4N KOH in 1: 1 methanol:
benzene. After extracting the unsaponified matter with hexane, the extract was dried over anhydrous sodium
sulfate, concentrated by a stream of N2 for UVF analysis.
2 Results and Discussion
The concentrations of TPHs in soil samples at ten stations were range as following: Station 1 (14.75-20.19 µg/g),
station 2 (16.91-20.59 µg/g), station 3 (17.75-22.46 µg/g), station 4 (22.39-26.82 µg/g), station 5 (24.85-32.29 µg/g),
station 6 (22.75-28.45 µg/g), station 7 (27.05-35.69 µg/g), station 8 (29.56-38.5 µg/g), station 9 (29.57-39.17 µg/g)
and station 10 (33.37-41.94 µg/g) dry weight (Table 1).
The mean concentration during different season range in station 1 from 14.82 µg/g during spring to 20.1 µg/g during
winter, while station 2 ranged from 16.99 µg/g during spring to 20.53 µg/g during winter, whereas station3 ranged
from17.77 µg/g during summer to 22.42 µg/g during winter, station4 ranged from 22.43 µg/g during spring to 26.76
µg/g during winter, station5 ranged from 24.87 µg/g during summer to 32.23 µg/g during winter, station 6 ranged
