Journal of Environmental Protection, 2011, 2, 700-709
doi:10.4236/jep.2011.26081 Published Online August 2011 (http://www.SciRP.org/journal/jep)
Copyright © 2011 SciRes. JEP
PAHs in Sediments along the Semi-closed Areas of
Alexandria, Egypt
Mohamed A. Shreadah1, Tarek O. Said1*, Mohamed I. Abd El Monem1, Eiman M. I. Fathallah2,
Mohamed E. Mahmoud1
1National Institute of Oceanography and Fisheries, Alexandria, Egypt; 2Chemistry Department, Faculty of Science, Alexandria Uni-
versity, Alexandria, Egypt.
Email: tareksaideg@yahoo.co.uk
Received May 9th, 2011; revised June 12th, 2011; accepted July 25th, 2011.
ABSTRACT
Sediment samples were collected from 49 sampling stations along the semi-closed areas of Alexandria coasts, Egypt.
Total concentrations of 15 out of 16 EPA-PAHs in sediments were varied from 4.2 to 886 ng·g1 with an average value
of 176 ng·g1 (dry wt). The average total organic carbon (TOC) percent was varied from 0.04 to 7.65%. Higher con-
centration of total pyrolytic hydrocarbons (COMB) than total fossil hydrocarbons (COMB), declared that atmos-
pheric fall-out is the significant source of PAHs to marine sediments of the semi-closed area of Alexandria. The selected
marked compounds and special PAHs compound ratios (phenanthrene/anthracene; fluoranthene/pyrene; COMB/
EPA-PAHs) suggest the pyrogenic origins, especially traffic exhausts, are the dominant sources of PAHs in most lo-
cations. Interferences of rather petrogenic and pyrolytic PAH contaminations were noticed in the harbours, especially
marine area due to petroleum products deliveries and fuel combustion emissions from the ships staying alongside the
quays.
Keywords: Surface Sediment, PAHs, Alexandria, Egypt, GC-MS
1. Introduction
Polycyclic aromatic hydrocarbons (PAHs) have been
described as mutagenic, carcinogenic and teratogenic
included in the US EPA and the EU priority pollutants
list [1]. PAHs solubility decrease with increasing mo-
lecular weight [2]. Consequently, the uptake of a con-
taminant is governed by its bioavailability, and organ-
isms are often enriched in the lower molecular weight
PAHs relative to the sediment [3]. Once deposited in
sediments, PAHs are less subjected to photochemical or
biological oxidation, especially if the sediment is anoxic.
Thus, sedimentary PAHs tend to be persistent and may
accumulate to high concentrations [4]. Numerous re-
search studies assessed the PAHs inputs in the North-
western and Central Mediterranean [5]. Conversely, in
the Eastern Mediterranean few data have been published
on the presence of PAHs in coastal sediments close to
point sources (municipal and river discharges, etc.) [6].
In addition, hydrocarbon budgets are available for the
Western part of Mediterranean Sea [7], but there is a
tremendous lack of information regarding the Southern
Mediterranean [8].
This is the first systematic study to be undertaken
along the semi-closed areas of Alexandria (Egyptian Me-
diterranean Sea coast) as a comparative study between
four sectors of different identity. Two relevant criteria
are used fairly to discriminate between the various natu-
ral and anthropogenic hydrocarbon inputs and to evaluate
the extent of hydrocarbon pollution in the area and its
link to combustion processes and/or releasing of un-
burned fossil fuels.
2. Materials and Methods
A total of 49 surface sediment samples were collected
during January 2010 at sites shown in Figure 1. Sedi-
ments were collected utilizing a stainless-steel grab. Six
grabs were taken from each location from which the top
3 cm were scooped into pre-cleaned wide-mouth glass
bottles, frozen and transported to the laboratory and
stored at 20˚C until analysis. The samples were ana-
lyzed for PAHs following well established techniques
[9].
To control the analytical reliability and assure recov-
ery efficiency and accuracy of the results, 6 analyses
PAHs in Sediments along the Semi-Closed Areas of Alexandria, Egypt701
29.829.9 30 30.130.2
31.1
31.15
31.2
31.25
31.3
31.35
A
B
C
D
Figure 1. Sampling locations collected from the area of in-
vestigation: (A) Abu Qir Bay, (B) Eastern Harbour, (C)
Western Harbour and (D) El Max Bay during 2010.
were conducted on PAH compound reference materials,
HS-5 (sediments) provided by NRC-IMB of Canada and
SRM-2974 (Freeze-dried mussels tissue) (Mytilus edulis)
provided by NIST of USA as well as sediment samples
of known PAH levels spiked with a mixture consisting of
2 μg each of PAHs were analyzed as above to validate
the analytical method used in this study. The lowest DL
was 0.01 μg/ml for lower molecular mass compounds
while indeno[1,2,3-cd]pyrene has the highest at 0.1 μg/ml.
The recovery efficiency ranged from 92% to 111% for
HS-5, 88% to 96% for SRM-2974 and 93% to 105% for
the spiked samples. Samples were analyzed by Gas
Chromatograph-Mass Spectrometer; GC-MS (Trace DSQ
II MS) with fully scanned 50 - 650 Daltons per second
mode and 70 eV electron energy for confirmation. GC/
MS is equipped with split/split less injector and a fused
silica capillary column; Thermo TR-35 MS (30 m, 0.25
mm, 0.25 μm) with 35% phenyl polysilphenylene-siloxane.
Helium was used as carrier gas at 1.5 mL·min1. The
temperature was programmed from 60˚C - 100˚C with
rate of 8˚C·min1, then maintained at 100˚C for 1min,
and from 100 - 300˚C with rate of 5˚C·min1 and was
maintained at 300˚C for 20 min. The injector and detec-
tor temperatures were set at 280˚C and 300˚C, respec-
tively. Three μL volume of each sample was injected in
the split less mode and the purge time was 1 min. The
response factor of individual PAH compounds to the
internal standard was measured and calculated at least
three times at the beginning, in the middle, and at the end
for each batch of GC injections (15 samples).
3. Results and Discussion
Individual and total concentrations, as well as character-
istic ratios for the identification of PAH origins are given
in Tables 1 and 2. Total PAHs (PAHs) ranged from 4.2
to 886.08 with an average of 169.37 ng·g1 dry weight.
The highest concentration of total PAHs was recorded in
sediments collected from station 28 (Eastern Harbour),
followed by that in stations 1, 26 and 34. Lower concen-
trations were detected in samples of stations 11 - 15. In
this study, sediment samples collected near the sewage
outlet, cities and harbor appeared to have extremely high
concentrations of total PAHs. These suggest that PAHs
accumulated in Mediterranean Sea sediments came from
different sources such as sewage discharge from nearby
human activities and fuel combustion emissions. Al-
though the number of PAHs analyzed in any given study
may differ, the 15 compounds analyzed herein comprise
the vast majority of PAHs found in most estuarine or
marine sediments. It has been demonstrated that the na-
ture of the sediment influences the distribution and con-
centration of PAHs. Sediments with high organic carbon
content were characterized with high values of PAHs
[10]. However, a moderate correlation of r = 0.646 was
found between PAHs and total organic carbon (TOC)
concentrations in the present sediments (Table 1, Figure
2). This may be suggesting that both of direct input and
type of sediment found locally would determine the dis-
tribution and concentrations of PAHs in sediments.
Moreover, the relationship between total PAHs and or-
ganic carbon was only significant for highly contami-
nated sites where total PAH concentration was greater
than 2000 ng·g1 dry wt. In this study, none of the sedi-
ment samples had total PAH concentrations more than
2000 ng·g1 where the samples contain lower TOC.
Chiou et al. [10] found that the high partitioning of
PAHs to sedimentary organic matter was mainly due to
the significant aromatic fraction of the organic matter.
All locations had concentrations lower than the Effects
Range-Low (ERL) value (4022 ng·g1) suggested by
Long et al. [11]. They reported that the concentrations
below the ERL value represent a minimal-effect range,
i.e. adverse biological effect would rarely be observed
below the ERL. On the other hand, if the concentration
was higher than the Effects Range-Median (ERM) value
(44792 ng·g1), adverse effects on biological systems will
frequently occur. The concentrations of individual PAH
recorded in the present study ranged from 4 to 886 ng·g1,
and were much lower than both of the ERL and ERM
limit (Table 3 and Figure 3). In addition, similar obser-
vations were found relative to the Threshold Effect Level
(TEL) and Probable Effect Level (PEL) [11], where Di-
benzo(a,h)anthracene, Acenapthylene and acenaphthene
have average concentrations > TEL and < PEL (Figure
4). The individual PAH concentrations in this study were
also lower than the national sediment quality criteria
proposed by USEPA [12] for fluoranthene (3000 ng·g1),
acenaphthylene (2400 ng·g1) and phenanthrene (2400
ng·g1). Benzo(a)pyrene (BaP), the most potent carcino-
genic PAHs, and the sum of six carcinogenic PAHs
Copyright © 2011 SciRes. JEP
PAHs in Sediments along the Semi-Closed Areas of Alexandria, Egypt
Copyright © 2011 SciRes. JEP
702
Table 1. Concentrations (ng/g; dry wt) of PAHs in sediment samples collected from the studied area during 2010.
Parameter
Site
PAHs Ph/An Flu/Py BaA/Chr ΣCARC %CARCΣTFPAH %ΣTFPAH ΣCOMP %ΣCOMP ΣTFPAH/
ΣCOMP BkF/BaP BbF/BaP%TOC
1 460.96 3.05 0.33 0.71 59.42 6.41 3.27 1.67 457.695.65 0.01 5.18 0.55 7.65
2 44.57 0.05 1.00 0.29 6.62 0.71 0.99 0.51 43.580.54 0.02 5.47 2.29 0.62
3 31.88 0.11 1.00 4.00 10.79 1.16 3.86 1.97 28.020.35 0.14 2.52 2.19 1.13
4 80.22 1.62 3.00 1.00 4.70 0.51 1.60 0.82 78.620.97 0.02 1.09 0.14 1.11
5 62.16 1.62 1.00 1.00 2.45 0.26 0.59 0.30 61.570.76 0.01 1.08 0.85 0.23
6 23.96 0.08 0.00 1.00 4.46 0.48 1.16 0.59 22.790.28 0.05 2.29 2.00 0.31
7 29.13 0.06 1.00 2.00 1.15 0.12 0.67 0.34 28.460.35 0.02 8.83 0.17 0.49
8 35.83 0.06 0.33 0.50 7.28 0.78 0.29 0.15 35.530.44 0.01 2.17 1.83 0.12
9 102.18 1.62 1.00 0.50 2.77 0.30 1.49 0.76 100.691.24 0.01 2.89 1.56 0.43
10 17.08 0.06 0.00 1.00 4.30 0.46 0.70 0.36 16.38 0.20 0.04 1.60 2.80
0.04
11 9.30 1.67 0.00 0.00 1.70 0.18 0.30 0.15 9.00 0.11 0.03 12.40 2.00 0.35
12 12.60 1.00 NR NR 6.60 0.71 0.50 0.26 12.100.15 0.04 1.96 1.56 0.31
13 4.20 2.00 NR 0.00 2.20 0.24 0.20 0.10 4.00 0.05 0.05 1.00 0.57 0.12
14 10.60 3.50 NR 0.20 3.90 0.42 0.20 0.10 10.40 0.13 0.02 2.00 0.32 0.23
15 7.40 2.33 NR 1.00 4.60 0.50 0.50 0.26 6.90 0.09 0.07 0.33 0.50 0.23
AV 62.14 1.26 0.79 0.94 8.20 0.88 1.09 0.56 61.050.75 0.04 3.39 1.29 0.89
Max 460.96 3.50 3.00 4.00 59.42 6.41 3.86 1.97 457.695.65 0.14 12.40 2.80 7.65
Min 4.20 0.05 0.00 0.00 1.15 0.12 0.20 0.10 4.00 0.05 0.01 0.33 0.14 0.04
16 56.9 0.71 14.00 0.04 11.37 1.23 0.58 0.30 56.370.70 0.01 3.70 0.29 1.56
17 268.9 1.62 0.37 0.02 4.52 0.49 1.32 0.67 267.583.30 0.00 6.57 1.43 2.24
18 183.7 3.44 24.50 0.09 8.30 0.89 5.40 2.76 178.302.20 0.03 3.00 0.86 2.13
19 130.20 1.62 23.00 0.33 18.33 1.98 1.86 0.95 128.331.58 0.01 1.74 0.32 0.59
20 78.00 0.03 1.31 0.33 8.94 0.96 0.98 0.50 77.01 0.95 0.01 3.68 0.27 0.45
21 36.40 0.03 0.95 2.00 3.91 0.42 2.94 1.50 33.46 0.41 0.09 0.87 0.61 0.21
22 192.79 1.62 1.36 0.63 7.02 0.76 2.08 1.06 190.71 2.35 0.01 17.44 1.19 0.44
23 215.11 0.02 1.42 0.04 40.46 4.36 0.70 0.36 214.412.65 0.00 1.72 0.02 0.69
24 182.12 4.87 28.00 0.50 3.93 0.42 1.28 0.65 180.842.23 0.01 3.61 0.48 0.50
25 170.94 1.61 0.00 0.50 1.36 0.15 2.82 1.44 168.12 2.07 0.02 9.00 2.33 0.49
26 339.13 4.86 1.31 1.33 27.17 2.93 1.19 0.61 337.944.17 0.00 1.84 0.19 1.02
27 196.88 0.04 0.01 0.02 50.15 5.41 1.75 0.90 195.132.41 0.01 2.06 0.08 1.22
PAHs in Sediments along the Semi-Closed Areas of Alexandria, Egypt703
28 886.1 6.04 1.24 0.85 143.47 15.460.57 0.29 885.5110.93 0.00 1.95 0.03 3.18
AV 225.9 2.0 7.5 0.5 25.3 2.7 1.8 0.9 224.12.8 0.0 4.4 0.6 1.1
Max 886.1 6.0 28.0 2.0 143.5 15.5 5.4 2.8 885.510.9 0.1 17.4 2.3 3.2
Min 36.4 0.0 0.0 0.0 1.4 0.1 0.6 0.3 33.5 0.4 0.0 0.9 0.0 0.2
29 266.4 1.62 4.20 0.04 23.68 2.55 2.70 1.38 263.743.25 0.01 2.22 0.25 2.67
30 292.8 2.79 1.40 0.23 46.50 5.01 14.807.56 278.003.43 0.05 2.75 0.43 6.00
31 47.8 0.06 1.00 1.50 4.92 0.53 1.98 1.01 45.790.57 0.04 3.50 1.35 0.36
32 356.9 0.62 1.26 11.94 78.00 8.41 0.90 0.46 356.004.39 0.00 2.59 1.55 2.71
33 184.8 0.03 1.20 4.17 45.80 4.94 3.40 1.74 181.402.24 0.02 2.12 0.51 3.96
34 542.3 0.53 4.88 0.08 11.20 1.21 2.90 1.48 539.406.66 0.01 3.60 1.03 2.89
35 205.3 0.01 1.08 0.12 7.29 0.79 1.40 0.71 203.892.52 0.01 8.62 2.15 1.82
36 56.7 0.02 4.25 0.83 13.00 1.40 2.20 1.12 54.500.67 0.04 1.63 0.41 0.63
37 719.0 0.68 9.71 0.80 153.80 16.582.40 1.23 716.608.84 0.00 2.33 0.07 3.58
38 157.6 42.11 3.63 7.85 36.60 3.94 1.90 0.97 155.701.92 0.01 14.05 2.74 2.81
39 181.2 0.06 3.26 0.07 21.19 2.28 2.39 1.22 178.812.21 0.01 2.07 0.08 3.09
AV 273.7 4.4 3.3 2.5 40.2 4.3 3.4 1.7 270.33.3 0.0 4.1 1.0 2.8
Max 719.0 42.1 9.7 11.9 153.8 16.6 14.8 7.6 716.68.8 0.1 14.1 2.7 6.0
Min 47.8 0.0 1.0 0.0 4.9 0.5 0.9 0.5 45.8 0.6 0.0 1.6 0.1 0.4
40 73.3 0.38 0.10 NR 2.98 0.32 24.3812.46 48.900.60 0.50 3.33 1.44 0.49
41 281.9 1.62 1.00 NR 6.57 0.71 1.03 0.52 280.903.47 0.00 1.17 3.67 2.17
42 200.9 1.47 1.50 1.00 2.52 0.27 0.80 0.41 200.132.47 0.00 1.00 0.70 0.93
43 201.1 1.74 1.24 1.00 1.62 0.17 1.89 0.97 199.192.46 0.01 27.50 3.50 1.26
44 119.5 2.12 0.80 1.00 3.40 0.37 0.85 0.43 118.691.46 0.01 1.78 1.67 0.30
45 100.2 0.11 1.00 2.00 3.02 0.33 44.92 22.96 55.240.68 0.81 2.29 1.43 1.54
46 226.6 1.65 0.77 1.00 3.13 0.34 32.62 16.67 193.952.39 0.17 1.73 0.80 0.61
47 70.8 0.19 3.80 1.00 3.20 0.35 6.40 3.27 64.400.79 0.10 1.42 0.75 0.73
48 22.9 2.77 1.50 NR 3.54 0.38 1.27 0.65 21.650.27 0.06 1.00 0.33 0.30
49 121.8 3.42 2.00 1.00 3.93 0.42 4.77 2.44 117.061.44 0.04 1.63 4.75 0.42
AV 141.9 1.5 1.4 1.1 3.4 0.4 11.9 6.1 130.01.6 0.2 4.3 1.9 0.9
Max 281.9 3.4 3.8 2.0 6.6 0.7 44.9 23.0 280.93.5 0.8 27.5 4.8 2.2
Min 22.91 0.11 0.10 1.00 1.62 0.17 0.80 0.41 21.650.27 0.00 1.00 0.33 0.30
Abu Qir Sector from 1 - 15; Eastern Harbour sector: 16 - 28, Western Harbour sector: 29 - 39, El Max sector: 40 - 49, Av: average, Max: maximum, Min:
minimum, PAHs: Sum of aromatic hydrocarbons, Phe: phenanthrene, An: anthracene, Flu: Fluoranthene, Py: pyrene, BaA: Benzo(a)anthracene, Chr: Chrysene,
BkF: benzo(k)flouranthene, BaP: benzo(a)pyrene, BbF: benzo(b)fluoranthene, ΣCARC: Sum of BaA + BbF + BkF + BaP + DBA + InP, ΣTFPAH: Sum Ace-
naphthylene + Acenaphthene, ΣCOMP: Sum of all PAHs except those calculated for ΣTFPAH.
Copyright © 2011 SciRes. JEP
PAHs in Sediments along the Semi-Closed Areas of Alexandria, Egypt
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Table 2. Concentrations (ng/g; dry wt) of individual PAHs in sediment samples during 2010.
Compound Concentration, ng/g
Site Naph Acthy AcePhe Ant Flu Pyr BaAChr BbFBkFBaP InP DBAB(ghi)P
1 0.00 1.92 1.35196.7 64.42 3.6510.96 33.46 46.927.8873.65 14.23 0.58 3.271.92
2 0.00 0.49 0.491.28 25.00 0.100.100.200.693.859.191.68 0.40 0.490.59
3 0.50 3.17 0.20 0.89 7.92 0.10 0.10 0.40 0.10 6.73 7.723.07 0.30 0.300.40
4 0.10 1.30 0.2042.66 26.37 0.300.100.100.100.503.803.50 0.20 0.400.60
5 0.00 0.29 0.2935.29 21.76 0.100.100.100.101.081.371.27 0.00 0.000.39
6 0.10 0.58 0.481.07 13.87 0.000.100.190.192.723.101.36 0.00 0.190.00
7 0.10 0.19 0.381.25 20.67 0.100.100.190.100.105.100.58 0.10 0.190.00
8 0.00 0.19 0.101.36 21.07 0.100.290.100.194.275.052.33 0.10 0.490.19
9 0.10 1.29 0.1058.51 36.14 0.100.100.100.201.392.570.89 0.20 0.200.30
10 0.10 0.20 0.400.60 9.69 0.00 0.100.10 0.10 2.80 1.601.00 0.20 0.200.00
11 0.00 0.10 0.200.50 0.30 0.00 0.100.00 0.10 1.00 6.200.50 0.10 0.100.10
12 0.00 0.00 0.500.20 0.20 0.00 0.000.20 0.00 3.90 4.902.50 0.00 0.000.20
13 0.00 0.20 0.000.20 0.10 0.00 0.000.00 0.10 0.80 1.401.40 0.00 0.000.00
14 0.10 0.00 0.100.70 0.20 0.10 0.000.10 0.50 0.80 5.002.50 0.30 0.200.00
Abu Qir Bay
15 0.00 0.40 0.100.70 0.30 0.00 0.000.10 0.10 1.50 1.003.00 0.00 0.000.20
16 0.10 0.29 0.190.97 1.36 2.72 0.190.3910.882.1427.317.39 0.39 1.071.55
17 0.09 0.94 0.28143.5 88.69 2.927.820.199.901.898.671.32 0.28 0.851.51
18 0.20 0.40 4.80117.1 34.00 4.900.200.202.203.0010.503.50 0.40 1.201.10
19 0.10 0.59 1.1852.55 32.45 2.250.100.200.593.9221.47 12.35 0.59 1.270.59
20 0.10 0.59 0.291.18 39.88 1.671.280.290.881.67 22.40 6.09 0.59 0.290.79
21 0.10 1.47 1.370.59 22.80 1.761.860.200.101.371.962.25 0.10 0.000.49
22 0.10 0.89 1.0988.93 54.94 5.934.350.490.791.8827.571.58 0.79 2.271.19
23 0.00 0.40 0.300.70 38.27 30.0221.171.2934.790.70 48.0127.93 0.80 9.740.99
24 0.10 0.79 0.39136.9 28.09 2.750.100.200.391.088.152.26 0.20 0.200.49
25 0.87 0.39 1.55100.8 62.59 0.10ND 0.100.190.682.620.29 0.10 0.190.49
26 ND 0.69 0.49193.9 39.92 20.65 15.810.400.304.1539.62 21.54 0.49 0.590.59
27 0.19 1.27 0.293.41 84.71 0.107.400.29 12.95 1.36 36.0317.53 22.69 8.280.39
Eastern Habour
28 0.09 0.28 0.19379.9 62.88 61.84 49.91 69.89 82.481.61104.553.50 1.42 17.050.47
29 0.10 2.20 0.40102.1 63.14 6.291.501.3033.573.7032.8714.79 1.90 2.000.60
30 0.30 0.50 14.00 70.90 25.40 14.30 10.20 12.40 53.608.6055.0020.00 1.10 4.402.10
Western har-
bour
31 0.08 0.79 1.111.90 32.62 0.080.080.240.162.145.561.59 0.32 0.630.48
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32 0.10 0.40 0.4077.20 125.5 10.208.1021.501.8031.8053.1020.50 2.70 1.502.10
33 0.40 2.80 0.202.80 80.20 1.201.005.001.20 11.6047.8022.60 1.00 5.601.40
34 0.10 1.90 0.90174.0 329.1 3.900.800.506.403.1010.803.00 1.90 2.703.20
35 ND 1.10 0.301.70 158.7 5.294.891.70 14.27 2.7911.181.30 1.00 0.500.60
36 ND 0.40 1.800.60 25.50 1.700.400.500.602.90 11.607.10 0.80 1.701.10
37 0.10 2.10 0.20113.0 165.5 34.003.5089.30 111.64.00133.3 57.30 2.20 1.001.90
38 0.10 1.60 0.20 75.80 1.80 6.901.90 25.90 3.305.20 26.70 1.90 2.50 1.102.70
39 0.10 1.99 0.302.59 46.37 12.643.884.18 61.891.0928.8613.93 1.29 0.701.39
40 ND 13.75 10.64 10.64 28.27 0.262.59ND ND 1.693.891.17 ND 0.130.26
41 0.21 0.62 0.21168.0 103.7 0.210.21ND 0.214.521.441.23 0.41 0.410.62
42 0.13 0.53 0.13116.2 79.02 0.400.270.130.130.931.331.33 0.13 ND 0.27
43 0.13 0.81 0.94115.2 66.40 4.183.370.130.130.947.420.27 0.27 ND 0.81
44 0.12 0.49 0.2468.45 32.28 5.226.550.120.121.821.941.09 ND 0.360.73
45 0.16 44.44 0.324.76 44.13 0.160.160.320.161.592.541.11 ND ND 0.32
46 ND 24.71 7.91109.7 66.60 4.886.350.200.201.172.541.46 0.20 0.100.59
47 ND 6.02 0.388.83 46.73 2.430.640.130.131.152.181.54 0.13 0.260.26
48 0.13 1.14 ND 10.51 3.80 0.380.25ND 0.130.892.662.66 ND ND 0.38
El Max
49 ND 4.68 0.0886.12 25.17 0.330.170.080.083.181.090.67 ND ND 0.17
Table 3. ERL and ERM for PAHs recorded in sediment
according to Long et al. [11].
ERM ERL Component, ng/g
500 16 Acenaphthene
640 44 Acenaphthylene
1100 85.3 Anthracene
540 19 Fluorene
2100 160 Naphthalene
1500 240 Phenanthrene
1600 261 BaA
1600 430 BaP
2800 384 Chrysene
260 63.4 Dibenzo(a,h)Anthracene
5100 600 Fluoranthene
2600 665 Pyrene
20340 2967 Total PAHs
ERL = concentration at lower tength percentage at which adverse observed,
ERM = concentration at which adverse effects were observed at 50% of test
organisms.
(PAHCARC) [13] were highest at stations number 37
and 28 with 153.8 and 143.47 ng/g, respectively (Table
1). BaP was ranged from 0.27 at station 43 to 57.30 ng·g1
at station 37 with a mean of 7.63 ng·g1, falling in the
concentration range between rural and urban areas [14].
One difficulty in identifying PAH origins is the possi-
ble coexistence of many contamination sources, and the
transformation processes that PAHs can undergo before
deposition in the analyzed sediments. Nevertheless, some
compounds could exhibit comparable evolution kinetics
that could be used to identify the origin of organic matter
in the environment [15]. The compounds of pyrene, phe-
nanthrene and benzo(b)fluoranthene are components of
fossil fuels and a portion of them is associated with their
combustion. Benzo(a)pyrene is usually emitted from
catalyst and no catalyst automobiles. Benzo(a)anthracene
and chrysene are often resulted from combustion of both
diesel and natural gas [16]. The ratio of sum of major
combustion specific compounds (COMB, Flu, Pyr,
BaA, Chr, BbF, BkF, BaP, InP and BghiP) to the sum of
16 EPA-PAHs (COMB/PAHs) were ranged from
0.55 to 1.0 and the COMB concentrations displayed
values from 4 to 885.5 ng·g1 (Table 1), representing
average of 96% of total anthrpogenic PAHs. This ratio o
PAHs in Sediments along the Semi-Closed Areas of Alexandria, Egypt
706
0
100
200
300
400
500
600
700
800
900
1000
012345678
TOC%
Conc., P AHs, ng/g; dry wt.
9
Figure 2. A plot of total PAHs concentration (ng/g; dry wt) vs. %TOC of the sediments collected from the studied sediments
(r = 0.646).
0.1
1
10
100
1000
10000
100000
Naph
Acthy
Ace
Ph e
An t
Flu
Pyr
Ba A
Ch r
Ba P
DBA
PAHs
Component
Conc., ng/g
Average ERLERM
Figure 3. Diagram showed the average concentration (ng·g1; dry wt) of PAH in Mediterranean Sea sediments relative to
ERL and ERM.
was 1 at stations 17, 23, 26 and 28 (Eastern Harbour);
stations 32, 37 (Western Harbour); stations 41 and 42 (El
Max Bay), which indicated that the PAHs at these sites
manly come from combustion origin. The higher
COMB/PAHs ratio values further indicated that ex-
tensive combustion activities affected the PAHs in sedi-
ment samples. The sources of PAHs, where from fuel-
combustion (pyrolytic) or from crude oil (petrogenic)
contamination, may be identified by ratios of individual
PAH compounds based on peculiarities in PAH compo-
sition and distribution pattern as a function of the emis-
sion source [17]. Ratio values such as phenanthrene/an-
thracene (Phe/Ant) and fluoranthrene/pyrene (Flu/Pyr)
had been used by previous workers [18]. Petroleum often
contains more phenanthrene relative to anthracene as
phenanthrene that is more a thermodynamically stable
Copyright © 2011 SciRes. JEP
PAHs in Sediments along the Semi-Closed Areas of Alexandria, Egypt707
0. 00
200. 00
400. 00
600. 00
800. 00
1000.00
1200.00
1400.00
1600.00
Naph
Acthy
Ace
Phe
Ant
Flu
Pyr
BaA
Ch r
BaP
DBA
PAH compound
Concentration, ng/ g; dry wt.
Average TELPEL
Figure 4. Diagram showed the average concentration (ng·g1) of average PAH components in sediment samples Threshold
Effect Level (TEL) and Probable Effect Level (PEL).
tricyclic aromatic isomer than anthracene, so a Phe/Ant
ratio is observed to be very high in PAH petrogenic pol-
lution, but low ratio in pyrolytic contamination cases.
Crude oil had a Phe/Ant ratio of around 50, and motor
vehicle exhaust had a ratio of around four [19]. Low
Phe/Ant ratio values (<10) indicated the major PAH in-
put was from combustion of fossil fuel. Sediments with
Phe/Ant>10 were mainly contaminated by petrogenic
inputs and Phe/Ant <10 was typical of pyrolytic sources.
In the present study, the ratio of Phe/Ant compounds was
< 10, reflecting pyrolytic derived PAHs except for station
38 (repairing ship station) which recorded Phe/Ant ratio
> 10 (ratio = 42.11), indicating petrogenic derived PAHs
in such station. In other sediments the Phe/Ant ratio val-
ues were around 0.01 - 6.04 (Table 1), suggesting that
they were pyrolytic-derived PAHs. On the other hand
fluoranthene/pyrene (Flu/Pyr) ratio also indicated the
origin of PAHs. Sicre et al. [20] suggested that a Flu/Pyr
ratio of less than 1 was attributed to petrogenic sources
and values greater than 1 were obviously related to a
pyrolytic origin. Combustion of coal and wood gave
Flu/Pyr ratios of 1.4 and 1, respectively, while crude oil
and fuel oil had values of 0.6 - 0.9 [20]. In the present
study, most sites had Flu/Pyr ratio values more than 1
(Table 1).
The PAHs whose concentrations are susceptible of
co-varying in the environment were identified in this
study on the basis of the correlation factor values (Table
4). This statistical approach is based on the fact that each
pollution source produces a characteristic PAH pattern;
so, the correlations of all the individual PAHs can give
an idea whether they all originate from the same source
or not. A lack of correlation was noticed between an-
thracene and other PAHs (r = 0.116 to 0.304). Significant
correlations were noted between Flu-Phe (r = 0.602),
Flu-Pyr (r = 0.882), Flu-BaA (r = 0.759), Pyr–Phe (r =
0.645), %TOC-Phe (r = 0.458), %TOC-BaA (r = 534),
%TOC-Chr (r = 0.629), %TOC-BKF (r = 0.669), %TOC-
BghiP (r = 0.697). These indicated that Flu, Phe, Pyr,
BaA and Chr might originate from the same sources.
Chrysene and benzo(a)anthracene are derived from pro-
cesses of organic matter combustion at high temperature,
with values of Chr/BaA ratio lower than 1. In contrast,
low maturation of organic matter during burial in the
sedimentary matrix could lead to an inversion of this
tendency: Chr/BaA = 1 [18]. It has been shown that
chrysene derivatives are more stable than benzanthrace-
nic ones because of the possibility of the latter ones to
convert to chrysene compounds.
4. Conclusions
The present work represents the detailed study of the
distribution and origin of petroleum hydrocarbons in 49
sediment samples collected from the semi-closed areas
along the semi-closed areas of Alexandria, Egypt. The
studied samples were less contaminated by petroleum
hydrocarbons. Concentrations of PAHs in Mediterranean
Sea sediments are shown to be substantially lower than
those from other coastal areas and are generally compa-
rable to levels encountered in the other Mediterranean
Sea coast. The most contaminated site (886 ng·g1) was
the Eastern Harbor (station 8). A mixture of pyrolytic 2
Copyright © 2011 SciRes. JEP
PAHs in Sediments along the Semi-Closed Areas of Alexandria, Egypt
708
Table 4. Correlation coefficient matrix for sediment individual PAHs (n = 49).
Compound Naph Acthy Ace Phe Ant Flu Pyr BaAChr BbFBkF BaP InP DBA B(ghi)P%TOC
Naph 1
Acthy 0.028 1.000
Ace 0.084 0.245 1.000
Phe 0.065 0.065 0.046 1.000
Ant 0.072 0.027 0.042 0.406* 1.000
Flu 0.073 0.084 0.032 0.602*** 0.208 1.000
Pyr 0.087 0.055 0.072 0.645*** 0.116 0.882*** 1.000
BaA 0.022 0.060 0.023 0.517** 0.274 0.759*** 0.547***1.000
Chr 0.016 0.082 0.115 0.409* 0.275 0.775*** 0.561*** 0.828*** 1.000
BbF 0.106 0.079 0.067 0.080 0.229 0.0730.0790.2230.0461.000
BkF 0.015 0.126 0.048 0.472** 0.304 0.794*** 0.625*** 0.880***0.865***0.3381.000
BaP 0.016 0.113 0.010 0.442** 0.269 0.869*** 0.688*** 0.827***0.843***0.2610.945*** 1.000
InP 0.085 0.059 0.050 0.035 0.204 0.0360.1280.0770.1290.0610.2270.238 1.000
DBA 0.055 0.114 0.033 0.455** 0.174 0.747*** 0.852***0.470** 0.530** 0.075 0.629*** 0.699*** 0.394* 1.000
B(ghi)P 0.084 0.100 0.172 0.320 0.566*** 0.2480.1320.374*0.372*0.440**0.485** 0.321 0.086 0.193 1.000
%TOC 0.145 0.009 0.270 0.458** 0.385* 0.358*0.338 0.534**0.629*** 0.419*0.669***0.503** 0.106 0.378* 0.697***1.000
Correlations are significant at *p < 0.05 (low significant), **p < 0.01 (moderate significant) and ***p < 0.001 (high significant).
and petrogenic PAHs were observed with a major pyro-
lytic predominance.
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