Abstracts
Krupp, F., Abuzinada, A.H. & Nader, I.A. (eds.), A Marine Wildlife Sanctuary for the Arabian Gulf. Environmental research and conservation following the 1991 Gulf War Oil Spill. NCWCD, Riyadh and Senckenberg Research Institute, Frankfurt a.M.
 

Hydrocarbon concentrations in two intertidal areas of Saudi Arabia following remediation with mechanical clean-up techniques after the Gulf War oil spill

A b s t r a c t: A variety of different post-spill clean-up operations were performed on intertidal sediments of the Gulf coast of Saudi Arabia following the oil spill in 1991. Two such remediation techniques were a dry rotivating (ploughing) process, and a high-pressure sea water jet flushing system, both designed for use on soft sediments. The remediated sediments were compared to the adjacent untreated sediments with regard to the degree of hydrocarbon contamination and the degradation of aliphatic crude oil components. Hydrocarbon analyses made more than one year after treatment suggested that ploughing facilitated the degradation of hydrocarbons, particularly towards the spring high water mark where the thickness of the tar layer was greatest. Approximately six months after the clean-up with the high-pressure sea water jet flushing system, between 13 and 19 % less oil was present in the treated sediments compared to adjacent untreated sediments. Previous evaluations of similar techniques have, however, given higher removal efficiencies. The sea water jet flushing system was also observed to cause increased penetration of the oil into deeper non-oiled sediments but some minor technical alterations could easily overcome this problem. The most appropriate time to carry out this sea water jet flushing remediation process would be as soon after an oil spill as possible.

 

additional information:

Table 1: Hydrocarbon concentrations, proportions and degradation indices in sediments at a low-energy (LE) site (not covered by tar) taken in 1992 and 1994. HWM = Mean high water mark; MWM = Mid water water mark 50 m below the bank; LWM = Low water mark 100 m below the bank. These are arbitrary names for the MWM and the LWM as the true positions were much greater.

Intertidal station

Sediment

Oil

Resolved aliphatics

Unresolved aliphatics (UCM)

Degradation indices

and replicate

depth

extracred

Total

Total

Relative

n-C," /

n-C'R /

number

(em)

(g/kg)

(g/kg)

(g/kg)

(%)

pristane

phytane

1992


HWM (1)

0-10

6.48

169

3.01

46

0.5

0.7

HWM(2)

 

4.80

180

1.99

41

0.5

0.1

HWM (I)

10-20

0.04

35

< 0.05

-

-

-

HWM(2)

 

0.05

42

< 0.05

-

-

-

HWM (I)

20-30

0.06

33

< 0.05

-

-

-

HWM(2)

 

0.07

39

< 0.05

-

0.7

-

MWM (1)

0-]0

0.37

51

0.18

49

0.6

1.4

MWM(2)

 

0.46

45

0.30

65

1.6

0.6

MWM (1)

10-20

< 0.05

39

< 0.05

-

-

-

MWM(2)

 

0.06

39

< 0.05

-

0.8

-

LWM (1)

0-10

0.14

48

0.08

57

0.2

1.0

LWM(2)

 

0.69

40

0.31

45

0.9

1.0

LWM (1)

10-20

0.40

44

0.18

38

4.0

0.7

LWM(2)

 

< 0.05

39

< 0.05

-

0.8

-

1994


HWM (1)

0-10

3.89

128

0.91

23

3.9

0.4

HWM(2)

 

4.04

115

1.05

26

2.8

0.1

HWM (1)

10-20

< 0.05

40

< 0.05

-

-

-

HWM(2)

 

0.11

49

0.07

64

1.4

9.0

HWM (1)

20-30

< 0.05

35

< 0.05

 

3.2

9.8

HWM(2)

 

0.12

57

< 0.05

-

-

-

MWM(I)

0-] 0

0.42

82

0.16

38

3.8

6.1

MWM(2)

 

0.25

43

0.08

32

-

-

MWM(I)

10-20

0.11

38

< 0.05

-

-

-

MWM(2)

 

0.07

41

< 0.05

-

-

-

LWM (1)

0-10

0.25

48

< 0.05

-

-

7.8

LWM(2)

 

0.]0

41

< 0.05

-

-

-

LWM (1)

10-20

< 0.05

37

< 0.05

-

-

-

LWM(2)

 

< 0.05

31

< 0.05

-

-

-

 

Table 2: Hydrocarbon concentrations, proportions and degradation indices for sediments at a low-energy (LE) site beneath an extensive tar pavement (LET) taken in 1993 and 1994. MHWS = Mean high water spring mark, MHWN = Mean high water neap mark.

Intertidal station

Sediment

Oil

Resolved aliphatics

Unresolved aliphatics (UCM)

Degradation indices

and replicate

depth

extracted

Total

Relative

Total

Relative

n-C17 /

n-CIR /

number

(cm)

(g/kg)

(g/kg)

(%)

(g/kg)

(%)

pnstane

phytane

1993


MHWS(1)

0-5

91.5

3420

3.7

39.0

42.6

0.52

0.20

MHWS (2)

 

45.8

1357

3.0

17.4

38.0

1.02

0.37

MHWS (1)

5-15

25.6

618

2.4

12.5

48.8

0.17

0.12

MHWS (2)

 

13.5

439

3.3

6.2

45.9

0.14

0.11

MHWN (1)

0-5

31.9

1119

3.5

14.4

45.1

0.25

0.04

MHWN (2)

 

39.1

1311

3.4

16.5

42.2

0.23

0.03

MHWN (1)

5-15

1.9

85

4.5

0.4

21.0

0.42

0.09

MHWN (2)

 

7.5

252

3.4

2.3

30.7

0.21

0.02

1994


MHWS (1)

0-5

53.6

1224

2.3

14.0

26.1

0.29

0.04

MHWS (2)

 

19.8

521

2.6

11.2

56.6

0.18

0.02

MHWS (1)

5-15

11.7

332

2.8

4.2

35.9

0.34

0.02

MHWS (2)

 

15.4

452

2.9

9.2

59.7

0.26

0.04

MHWN(1)

0-5

54.7

646

1.2

14.0

25.6

0.21

0.02

MHWN(2)

 

41.2

480

1.2

14.0

33.9

0.22

0.02

MHWN(l)

5-15

4.9

313

6.4

2.1

42.9

0.32

0.03

MHWN(2)

 

6.3

350

5.6

1.6

25.4

0.24

0.02

 

Table 3: Hydrocarbon concentrations, proportions and degradation indices for sediments at a high-energy (HE) site taken in 1992 and 1994. (1) = The sediment appeared to have been eroded since the 1992 sampling data.

 

Sediment

Oil

Resolved aliphatics

Unresolved aliphatics (UCM)

Degradation indices

Intertidal station

depth

extracted

Total

Total

Relative

n-C17 /

n-C18 /

 

(cm)

(g/kg)

(g/kg)

(g/kg)

(%)

pristane

phytane

1992


150 m

0-10

4.77

195

2.16

45

0.8

0.2

200 m

0-10

0.48

49

0.23

48

1.1

2.8

300 m

0-10

2.89

143

1.66

57

0.6

0.1

400 m

0-10

1.27

65

0.68

54

0.6

0.4

1994


150 m

(1)

(1)

(1)

(1)

(1)

(1)

(1)

200 m

0-10

0.38

31

0.05

13

> 2.2

> 2.3

300 m

0-10

0.97

39

0.05

5

> 2.0

> 4.2

400 m

0-10

20.47

270

4.53

22

2.3

0.4

 

 
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