Sediment characterization
The grain size data reveal that the sediments in Sidi Krir Harbor (A) composed of different types of sand fractions (coarse, medium, fine). The mean size ranges between 0.45 Ф and 2.59 Ф with average value 1.54 Ф (Table 3). The mean size in Dekhila Harbor (B) fluctuates from 3.33 Ф (very fine sand) to 6.19Ф (fine silt) with an average value 4.68 Ф. The occurrence of fine sediments here may be due to the dominance of terrigenous fine grain size sediments. The inclusive graphic mean size (MZФ) of the Western Harbor (C) ranges between 2.08 Ф (fine sand) and 6.22Ф (fine silt) with the average value 4.34 Ф. It was found that, the majority of sediments consist mainly of silt fractions covering the bottom. In Damietta Harbor (D), the mean size ranges from 5.75 to 6.17 Ф. In this harbor the majority of sediments covering the bottom are silt (fine, and medium). The mean size in Port Said Harbor (E) varies between 3.00 (very fine sand) and 7.04 (very fine silt). However, the differences in grain size distribution can be attributed to the bottom configuration and dominant current regime.
Table 3
Sediment charactrization of sediments of studied harbors
Sediment
|
SidiKrir Harbor
|
|
|
Dekhila Harbor (B)
|
|
Western Harbor ( C)
|
|
Damietta Harbor (D)
|
|
Port Said Harbor (E )
|
|
characterization
|
Min.
|
Max.
|
Av.
|
SD
|
Min.
|
Max.
|
Av.
|
SD
|
Min.
|
Max.
|
Av.
|
SD
|
Min.
|
Max.
|
Av.
|
SD
|
Min.
|
Max.
|
Av.
|
S.D
|
Sand (%)
|
99.8
|
100.0
|
99.9
|
0.1
|
5.9
|
57.9
|
32.5
|
24.8
|
24.1
|
78.6
|
39.3
|
22.2
|
4.0
|
39.4
|
17.6
|
14.4
|
8.2
|
94.9
|
35.1
|
34.8
|
Silt (%)
|
0.0
|
0.4
|
0.1
|
0.2
|
31.3
|
72.6
|
52.5
|
19.1
|
15.6
|
67.1
|
45.3
|
17.6
|
29.2
|
87.7
|
53.0
|
26.6
|
5.1
|
66.0
|
39.7
|
21.9
|
Clay (%)
|
0.0
|
0.0
|
0.0
|
0.0
|
8.6
|
25.4
|
15.0
|
6.7
|
5.8
|
18.6
|
15.4
|
5.4
|
8.4
|
46.8
|
29.5
|
16.3
|
0.0
|
48.0
|
25.2
|
18.0
|
Mean (Ф)
|
0.45
|
2.59
|
1.54
|
0.8
|
3.33
|
6.16
|
4.68
|
1.2
|
2.08
|
6.22
|
4.34
|
1.5
|
5.75
|
6.17
|
6.0
|
0.2
|
3.0
|
7.04
|
5.3
|
1.5
|
Sorting (Ø)
|
0.8
|
1.2
|
1.0
|
0.2
|
0.8
|
3.0
|
2.1
|
0.9
|
2.05
|
3.31
|
2. 58
|
0.4
|
1.15
|
2.57
|
2.0
|
0.7
|
0.71
|
2.52
|
1.9
|
0.7
|
Skweness
|
-0.3
|
0.2
|
0.0
|
0.2
|
-0.4
|
0.4
|
0.1
|
0.3
|
-0.2
|
0.3
|
0.1
|
0.2
|
-0.5
|
0.3
|
-0.1
|
0.3
|
-0.1
|
0.4
|
0.1
|
0.2
|
Kurtosis
|
0.8
|
1.6
|
1.0
|
0.3
|
1.0
|
2.2
|
1.3
|
0.5
|
0.9
|
2.0
|
1.3
|
0.4
|
0.7
|
2.2
|
1.3
|
0.6
|
0.9
|
1.4
|
1.1
|
0.3
|
A (%)
|
14.7
|
22.2
|
17.94
|
2.7
|
49.4
|
67.9
|
57.9
|
8.3
|
56.8
|
65.9
|
61.21
|
3.9
|
40.3
|
54.6
|
48.33
|
6.8
|
30.4
|
56.7
|
46.08
|
11.3
|
TOC (%)
|
0.1
|
0.2
|
0.1
|
0.1
|
2.4
|
4.0
|
3.1
|
0.7
|
1.7
|
5.6
|
4.5
|
1.5
|
1.0
|
1.7
|
1.4
|
0.3
|
0.4
|
1.9
|
1.1
|
0.7
|
TCO3 (%)
|
84.0
|
99.6
|
92.5
|
7.3
|
79.4
|
88.6
|
82.9
|
4.1
|
20.1
|
90.5
|
66.1
|
24.0
|
11.1
|
20.2
|
16.0
|
3.9
|
13.9
|
21.4
|
17.9
|
3.0
|
TSiO3 (%)
|
0.0
|
16.0
|
8.0
|
7.0
|
11.4
|
20.6
|
17.2
|
4.1
|
9.5
|
79.9
|
33.9
|
24.0
|
79.8
|
89.0
|
84.0
|
3.9
|
78.6
|
86.1
|
82.2
|
3.0
|
TP (µg/g)
|
30.0
|
121.0
|
62.0
|
40.0
|
250.0
|
933.0
|
640.0
|
312.0
|
649.0
|
913.0
|
771.0
|
87.0
|
671.0
|
914.0
|
769.0
|
91.0
|
436.0
|
867.0
|
620.0
|
169.0
|
IP (µg/g)
|
16.0
|
92.0
|
38.0
|
32.0
|
205.0
|
743.0
|
484.0
|
247.0
|
482.0
|
882.0
|
634.0
|
149.0
|
648.0
|
710.0
|
680.0
|
27.0
|
370.0
|
708.0
|
555.0
|
133.0
|
OP (µg/g)
|
11.0
|
42.0
|
24.0
|
12.0
|
45.0
|
215.0
|
155.0
|
71.0
|
31.0
|
244.0
|
138.0
|
87.0
|
16.0
|
204.0
|
89.0
|
70.0
|
23.0
|
159.0
|
65.0
|
55.0
|
Ca (mg/g)
|
169.1
|
373.7
|
298.6
|
83.9
|
367.4
|
709.7
|
580.1
|
129.6
|
292.0
|
595.3
|
501.9
|
111.8
|
109.2
|
346.7
|
213.0
|
98.8
|
178.3
|
426.5
|
307.6
|
98.5
|
Mg (mg/g)
|
240.5
|
482.6
|
385.4
|
98.7
|
402.0
|
736.8
|
625.1
|
128.9
|
370.6
|
745.2
|
606.8
|
155.8
|
93.5
|
435.8
|
234.4
|
142.4
|
58.1
|
384.9
|
255.2
|
134.0
|
Na (mg/g)
|
7.7
|
21.3
|
14.3
|
5.1
|
25.3
|
30.2
|
28.2
|
1.8
|
15.3
|
19.1
|
17.2
|
1.5
|
18.6
|
37.7
|
26.1
|
7.0
|
10.3
|
33.5
|
21.7
|
8.3
|
K (mg/g)
|
0.0
|
0.2
|
0.1
|
0.1
|
0.8
|
1.2
|
1.1
|
0.2
|
0.8
|
1.8
|
1.6
|
0.4
|
2.3
|
3.3
|
3.0
|
0.4
|
2.9
|
4.9
|
4.1
|
0.7
|
Li (µg/g)
|
0.8
|
15.3
|
3.7
|
6.5
|
115.9
|
165.9
|
137.7
|
20.3
|
18.6
|
173.6
|
94.2
|
59.1
|
33.8
|
49.9
|
40.7
|
6.4
|
38.3
|
59.7
|
50.2
|
8.0
|
B (mg/g)
|
2.3
|
5.7
|
3.4
|
1.5
|
4.7
|
14.1
|
8.0
|
4.4
|
3.5
|
6.9
|
5.0
|
1.4
|
3.0
|
4.1
|
3.5
|
0.5
|
2.8
|
4.4
|
3.5
|
0.8
|
SO4 (mg/g)
|
1.9
|
7.4
|
4.1
|
2.0
|
17.7
|
29.6
|
23.2
|
4.3
|
19.1
|
79.6
|
33.3
|
23.3
|
4.4
|
17.5
|
10.2
|
5.2
|
1.7
|
8.9
|
4.5
|
3.5
|
Cl (mg/g)
|
0.4
|
0.5
|
0.5
|
0.1
|
2.0
|
2.5
|
2.3
|
0.2
|
2.6
|
5.2
|
3.8
|
1.2
|
1.7
|
4.5
|
2.8
|
1.0
|
0.9
|
2.8
|
1.8
|
0.8
|
F (mg/g)
|
0.31
|
0.56
|
0.42
|
0.10
|
0.18
|
0.57
|
0.51
|
0.16
|
0.37
|
0.62
|
0.51
|
0.09
|
0.13
|
0.55
|
0.27
|
0.16
|
0.16
|
0.27
|
0.22
|
0.04
|
In Sidi Krir Harbor (A), the classification of sediments varies from moderately to poorly sorted Ф (Table 3). Whereas, in Dekhila Harbor (B), the sediments characteristics range between poorly sorted (0.80 Ф) and very poorly sorted (3 Ф). Poor sediments or ting mainly caused by the crushing the calcareous shells into fragments. At Western Harbor (C), the entire sediments are very poorly sorted. It varies between 2.05 Ф and 3.31 Ф with average value 2.58. The sediments in Damietta (D) and Port Said (E) harbors vary from poorly sorted (1.15 and 0.71 Ф, respectively) to very poorly sorted (2.57 and 2. 52 Ф, respectively). It was suggested that poorly sorted sediments indicate a variable or disturbance during sedimentation (Wigley 1961). The main factors controlling sorting are the range of the particle size of materials the supplied to environments, the types of deposition and the current characteristics (Yang and Sh 2019).
The percentage of water content (A %) well reflects the sediment texture of the examined sediment samples, and the variation in all different samples is relatively slight, while there is significant variation between the five studied harbors studied (Table 3). The harbor of Sidi Krir scores the lowest average A (17.94%), while the highest average is determined for the harbors of Dekhila and Western (57.90 and 61.21%, respectively). Harbors of Damietta and Port Said show relatively similar percentages of 48.33 and 46.08, respectively. For Dekhila Harbor, the displays results show good correlation between A % and each of TP % (r= 0.9647, p≤ 0.008), IP (r= 0.9830, p≤ 0.003), Fe (r= 0.9580, p≤ 0.010), Mn (r= 0.8957, p≤ 0.040), and Zn (r= 0.9560, p≤ 0.011). A% Damietta Harbor gives a weak correlation with TOC% (r= 0.8800, p≤ 0.049), while, Port Said Harbor explores good correlations between A % and each of TOC% (r= 0.9326, p≤0.021), TCO3 (r= 0.9865, p≤0.002), and Cl (r= 0.9412, p≤0.017). In contrast, A % does not specify any relationship to the sediment components of Sidi Krir and Western harbors. These correlations could be related to the uptake of the previously mentioned parameters at the inner surfaces as well as their condensation in the capillaries of the small pores.
Sorting(Ø) of the sediment indicates the fluctuation in the degree of kinetic energy and the effect of sedimentation system on the grain size characteristics (El-Said et al. 2014). It ranges from poorly sorted to very poorly indicating troubled conditions. Most of the sediments are observed from poorly sorted in Sidi Krir to very poorly locate in Western Harbor, Damietta and Port Said Harbor (Table 3).
Skewness values give information about the symmetry or asymmetry of the frequency distribution of the sediment, and the sign of skewness correlates with environmental energy (Bhattacharya et al. 2016).
Kurtosis plays a vital role in sediment characterization in different environments as explained by Duane (1964) It is also working as on internal sorting or distribution. Friedman (1962) suggested that very high or low values of kurtosis mean that a portion the sediment has achieved sorting elsewhere in a high-energy environment. Almost all studied samples are leptokurtic. It has been suggested that carbonate sands tend to be exclusively leptokurtic or peaked (Pikey et al. 1967). This is related to the dominance of the carbonate sands (El-Said et al. 2014).
Among the examined harbors sediments, the organic carbon content (TOC%) show high values in both the Dekhila and Western harbors (Table 3). TOC% at Dekhila Harbor ranges between 2.4 and 4.0%, while, the higher value is limited to station 3, which includes agricultural drainage, sewage, and industrial wastewater from Lake Mariout through El Umoum drain, heavy ship traffic, export, and import activities. And the high values of TOC% (1.74 - 5.63%) are recorded in most of the Western Harbor stations, which are severely affected by agricultural runoff from the El-Mahmoudiya and Noubaria canals and are also affected by household waste. Generally, the low organic carbon content in most harbor sediments is due to reduced bioactivity and good aeration of bottom sediments, as most of the sediment organic matter is oxidized and washed out. The distribution of total organic carbon in the studied harbor sediments is strongly influenced by the amount of CaCO3.
The total silicate content ranges between the maximum (84.0%) value in Damietta and the minimum in Sidi Krir Harbor (8.0%; Table 3). Total silicate contents show the opposite trend to the carbonate contents along the area of investigation.
The data presented reflect those sediments of Sidi Krir Harbor show the lowest average TP, IP and OP contents (62.0, 38.0 and 24.0 µg/g) among the other studied harbors (Table 3). OP content ranges from 11 to 42 µg/g with an average value (24 µg/g), representing 39% of the TP content. The correlation matrix yields high modulus values for TP&TOC% and IP&TOC% (r= 0.9881, p≤0.002 and r= 0.9901, p≤0.001, respectively), indicating the autolysis of dead cells of benthic organisms and their activities using phosphorus content (Pakzad et al. 2014).
The TP in the sediment harbors of Western Harbor and Damietta have higher average values (771.0 and 769.0 µg/g, respectively) than the other examined harbors. TP, IP and OP content of Dekhila Harbor varies from 250 to 933, 205.0 to 743.0 and 45 to 215 µg/g, respectively, where, IP and OP that count by 76 and 24%, respectively of TP. The positive correlations between TP&Silt% (r = 0.9875, p≤0.002) and IP&Silt (r = 0.995, p≤0.000) indicate that sediments with smaller grain size (clay and silt) have a greater ability to adsorb P (Jin et al. 2006; Kapanen 2008). Additionally, the presented data reflects the possible adsorption of phosphate with Fe, Mn, and Zn compounds (TP & Fe; r=0.9526, p≤ 0.012, TP & Mn; r=0.9157, p≤ 0.029 and TP & Zn; r=0.9332, p≤ 0.021, respectively). Also, these relations are agreement with the correlations of Fe & Mean% (r= 0.9355, p≤0.019), Mn &Mean% (r= 0.8860, p≤0.045), Zn&Mean% (r= 0.9673, p≤0.007, Fe&A% (r= 0.9580, p≤0.010), Mn&A% (r= 0.8957, p≤0.040), and Zn&A% (r= 0.9560, p≤0.011).
In Western Harbor sediments, the values of TP show high values ranging from 649.0 to 913 µg/g. IP contents are between 482 and 882 µg/g and represented 82% of the TP, while OP varies between 31 and 244 µg/g. Data reveal a significant positive association between TP& Zn (r= 0.8994, p≤0.015), IP&Ni (r= 0.9401, p≤0.005) and OP&Pb (r= 0.8521, p≤0.031) which reflects the potential adsorption of phosphate forms with their compounds. Also, the relationship of TP and F (r= 0.893, p≤0.017) indicates the formation of fluorapatite (Ca5(PO4)3F) (El-Said et al. 2015).
The average concentrations of TP, IP and OP in Damietta Harbor are 769.0, 680.0, and 89.0 µg/g, respectively. The relationships TP&Sit% (r= 0.8863, p≤0.045) and IP&Sit% (r= 0.9534, p≤0.012) show a significant positive association. Mn in the present work reflects high correlations between TP and OP (r = 0.9553, p≤0.011 and r= 0.9856, p≤0.002, respectively). While, IP shows negative significant relationships with B and SO4 (r= -0.9816, p≤0.003 and r= -0.8837, p≤0.047, respectively). Average concentrations of TP, IP and OP for Port Said Harbor are 620, 550 and 65 µg/g respectively and IP content represents about 90% of the TP. It is observed that TP and IP show a positive correlation with F (r = 0.9249, p≤0.024 and r= 0.9283, p≤0.023, respectively). In general, TP contents in surface sediments of all studied harbors are much significantly higher than those of the Sidi Krir Harbor. This could be because this harbor is relatively remote from the mainland with fewer human impacts such as agricultural activities, so fewer land-based sources of phosphorus would be expected.
Ca (580.1±129.6 mg/g), Mg (625.1±128.9 mg/g), Na (28.2±1.8 mg/g), B (8.0±4.4 mg/g), F (0.5±0.2 mg/g) and Li (137.7±20.3 µg/g) show the highest average contents at Dekhila Harbor (B) (Table 3). The Ca values determined in this study are relatively similar to those recorded along the Egyptian coast of Mediterranean Sea, but the Mg values detected are higher than those obtained at the Egyptian Mediterranean Sea coast (El-Said et al. 2010). The relationship between Ca and Mg in Dekhila Harbor and Sidi Krir Harbor (A) (r= 0.9757, p≤0.005 and r= 0.9806, p≤0.003, respectively) may attributed to the formation of aragonite and high Mg calcite (El-Said et al. 2021). The lowest Ca (213.0.1±98.8 mg/g), and Mg (234.4±142.4 mg/g), average contents are recorded at Damietta Harbor (D). The values recorded for Na (7.7-37.7 mg/g) and K (0.0-4.9 mg/g) in the current study are lower those recorded for the contaminated Egyptian Lake Mariout (18.33-39.25 mg/g and 0.91-5.99 mg/g, respectively) (El-Said et al. 2020). Minimum Cl (0.5±0.1 mg/g), K (0.1±0.1 mg/g), B (3.4±1.5 mg/g), SO4 (4.1±2.0 mg/g) and Li (3.7±6.5 µg/g) contents reflect the minimum amounts of pollutants at Sidi Krir Harbor (A). Relationship between Cl-TOC% (r= 0.9999, p≤0.000) Cl-IP (r= 0.9901, p≤0.001) and Cl-TP (r= 0.9881, p≤0.002) at Sidi Krir Harbor and chloride relationships of Cl-TOC% (r= 0.9329, p≤0.021), TCO3% (r= 0.8973, p≤0.039) and Cl-K (r= 0.9274, p≤0.023) are likely related to the water-soluble chloride compounds released and leached during the process of mineralization and weathering in Port Said (Harlove and Aranovich 2018). The highest average fluoride concentration (0.51±0.16 mg/g) is recorded at Dekhila Harbor (B), while the lowest (0.22±0.04 mg/g) is determined at Port Said Harbor (E). The highest recorded average fluoride content is within the amount of fluoride reported in ocean sediments (0.45-1.1 mg/g) (El-Said et al. 2010; 2016). The average amount of fluoride detected in Damietta Harbor (D) is relatively similar to that previously determined in it (0.25±0.31) (El-Said et al. 2016), whereas, the average value of fluoride recorded in Port Said is lower than that reported previously in this region (0.49±0.10) (El-Said et al. 2016).
Heavy metals distribution
The average concentration of heavy metals along the harbors examined indicates that their regions are predominantly Fe and Mn, with the exception of the Sidi Kriri Harbor which is predominantly Fe and Cu (Table 4). Among the heavy metals identified in the harbors, the harbor of Sidi Kriri shows the lowest heavy metal values, with the exception of Cu, which ranks second after the Western Harbor. Along the harbors, cadmium shows the lowest values ranging between 1.06 and 29.99 µg/g in harbors of Damietta and Western, respectively. Generally, the sediment quality guidelines (SQGs) indicate that most of the heavy metals identified (Cu, Ni, Cr, Pb and Cd) in the studied harbors rang between TEL and PEL values, with the exception of average Ni in harbors of Dekhila and Port Said, which is more than ERM values and Cd contents which are relatively similar to the ERM.
Table 4
Heavy metals concentration (µg/g) of sediments of studied harbors
Harbor
|
Station number
|
Fe
|
Mn
|
Zn
|
Cu
|
Ni
|
Cr
|
Pb
|
Cd
|
Sidi Krir
|
1
|
212.9
|
27.6
|
57.17
|
43.29
|
3.29
|
3.96
|
11.44
|
2.97
|
|
2
|
185.6
|
7.7
|
6.11
|
20.02
|
4.25
|
3.79
|
9.08
|
1.45
|
|
3
|
115.1
|
9.8
|
15.42
|
51.73
|
3.10
|
3.52
|
9.19
|
1.79
|
|
4
|
257.2
|
33.1
|
21.31
|
79.22
|
4.25
|
4.22
|
3.35
|
1.83
|
|
5
|
153.4
|
3.1
|
3.54
|
61.03
|
3.17
|
3.52
|
4.53
|
1.81
|
Minimum
|
|
115.1
|
3.10
|
3.54
|
20.02
|
3.10
|
3.52
|
3.35
|
1.45
|
Maximum
|
|
257.2
|
33.14
|
57.17
|
79.22
|
4.25
|
4.22
|
11.44
|
2.97
|
Average
|
|
184.9
|
16.27
|
20.71
|
51.06
|
3.61
|
3.80
|
7.52
|
1.97
|
S.D
|
|
54.5
|
13.26
|
21.60
|
21.89
|
0.59
|
0.30
|
3.43
|
0.58
|
Dekhila
|
6
|
5507.7
|
147.5
|
61.84
|
0.00
|
3.33
|
26.92
|
7.83
|
1.98
|
|
7
|
6867.2
|
188.4
|
57.59
|
8.77
|
206.14
|
4.29
|
12.31
|
4.07
|
|
8
|
10569.7
|
275.5
|
176.86
|
3.59
|
24.40
|
10.49
|
19.99
|
3.74
|
|
9
|
8237.7
|
236.0
|
82.37
|
43.80
|
21.35
|
8.93
|
4.08
|
5.00
|
|
10
|
10493.5
|
254.2
|
183.46
|
26.18
|
19.06
|
46.43
|
25.70
|
3.91
|
Minimum
|
|
5507.7
|
147.48
|
57.59
|
0.00
|
3.33
|
4.29
|
4.08
|
1.98
|
Maximum
|
|
10569.7
|
275.50
|
183.46
|
43.80
|
206.14
|
46.43
|
25.70
|
5.00
|
Average
|
|
8335.2
|
220.32
|
112.43
|
16.47
|
54.86
|
19.41
|
13.98
|
3.74
|
S.D
|
|
2225.5
|
51.86
|
62.58
|
18.28
|
84.96
|
17.35
|
8.84
|
1.10
|
Western
|
11
|
6633.4
|
209.5
|
208.47
|
886.98
|
54.29
|
14.96
|
17.48
|
4.05
|
|
12
|
9555.9
|
285.8
|
267.43
|
72.49
|
10.81
|
45.88
|
104.67
|
3.17
|
|
13
|
8606.4
|
313.4
|
290.48
|
114.64
|
70.83
|
99.32
|
14.65
|
5.38
|
|
14
|
6929.1
|
282.6
|
278.83
|
159.20
|
8.04
|
4.33
|
124.80
|
3.37
|
|
15
|
11312.1
|
273.3
|
133.57
|
101.05
|
6.51
|
73.72
|
12.82
|
5.50
|
|
16
|
11103.4
|
349.4
|
215.05
|
66.35
|
3.87
|
544.78
|
129.92
|
29.99
|
Minimum
|
|
6929.1
|
273.26
|
133.57
|
66.35
|
3.87
|
4.33
|
12.82
|
3.17
|
Maximum
|
|
11312.1
|
349.43
|
290.48
|
159.20
|
70.83
|
544.78
|
129.92
|
29.99
|
Average
|
|
9501.4
|
300.90
|
237.07
|
102.75
|
20.01
|
153.60
|
77.37
|
9.48
|
S.D
|
|
1821.1
|
30.98
|
64.64
|
37.32
|
28.52
|
221.49
|
58.86
|
11.51
|
Damietta
|
17
|
18212.6
|
840.9
|
104.44
|
28.96
|
127.34
|
97.94
|
9.30
|
1.23
|
|
18
|
17305.8
|
917.7
|
134.40
|
50.64
|
151.53
|
79.23
|
111.55
|
8.96
|
|
19
|
17513.6
|
553.9
|
87.48
|
32.34
|
134.99
|
84.27
|
8.50
|
1.06
|
|
20
|
17829.3
|
1280.0
|
93.73
|
29.51
|
158.29
|
84.34
|
8.70
|
1.87
|
|
21
|
17995.5
|
796.9
|
96.72
|
37.44
|
175.44
|
83.73
|
9.01
|
2.04
|
Minimum
|
|
17305.8
|
553.85
|
87.48
|
28.96
|
127.34
|
79.23
|
8.50
|
1.06
|
Maximum
|
|
18212.6
|
1280.03
|
134.40
|
50.64
|
175.44
|
97.94
|
111.55
|
8.96
|
Average
|
|
17771.4
|
877.88
|
103.36
|
35.78
|
149.52
|
85.90
|
29.41
|
3.03
|
S.D
|
|
364.5
|
262.79
|
18.39
|
8.96
|
19.08
|
7.06
|
45.92
|
3.34
|
Port Said
|
22
|
17015.4
|
1205.3
|
127.82
|
47.02
|
138.49
|
149.76
|
30.31
|
3.35
|
|
23
|
16795.2
|
1001.9
|
138.35
|
54.16
|
114.42
|
107.54
|
40.16
|
2.16
|
|
24
|
16967.8
|
1338.1
|
108.12
|
34.74
|
135.15
|
73.55
|
4.19
|
2.15
|
|
25
|
15551.9
|
615.3
|
63.85
|
6.57
|
76.75
|
126.25
|
3.37
|
1.50
|
|
26
|
18048.9
|
1176.8
|
105.38
|
27.20
|
150.77
|
174.57
|
11.72
|
1.94
|
Minimum
|
|
15551.9
|
615.35
|
63.85
|
6.57
|
76.75
|
73.55
|
3.37
|
1.50
|
Maximum
|
|
18048.9
|
1338.10
|
138.35
|
54.16
|
150.77
|
174.57
|
40.16
|
3.35
|
Average
|
|
16875.8
|
1067.49
|
108.70
|
33.94
|
123.11
|
126.33
|
17.95
|
2.22
|
S.D
|
|
889.3
|
279.69
|
28.58
|
18.54
|
29.03
|
38.78
|
16.48
|
0.69
|
Sediment quality guidelines (SQGs)
|
|
|
|
|
|
|
|
TEL
|
|
|
|
124
|
18.7
|
15.9
|
52.3
|
30.2
|
0.68
|
PEL
|
|
|
|
271
|
108
|
42.8
|
160
|
112
|
4.2
|
ERL
|
|
|
|
150
|
34
|
30
|
81
|
46.7
|
1.2
|
ERM
|
|
|
|
410
|
270
|
50
|
370
|
218
|
9.6
|
The correlation matrix for the studied parameters for each harbor shows that the heavy metals examined contribute to the sediment contamination and the geochemical properties of the sediments. In Sidi Krir Harbor this contribution is shown in the correlations of Cr-Fe (r=0.9685, p≤0.007), Cr-Mg (r=0.9033, p≤0.036), Cd-Zn (r=0.9505, p≤0.013), Cd- Li (r=0.9451, p≤0.015), and Cu-Na (r=-0.9433, p≤0.016). In Dekhila Harbor Fe-K(r=0.9146, p≤0.030), Mn-K (r=0.9301, p≤0.022), Ni-B (r=0.9456, p≤0.015), Ni-Cl (r=-0.9675, p≤0.007), Cd-Ca (r=0.9798, p≥0.003), and Cd-Mg (r=0.9748, p≥0.005) are obtained. In Western Harbor, heavy metals accumulation in sediments due to pollution sources is demonstrate by the following correlations of Zn-Li (r=0.8430, p≥0.035), Zn-F (r=0.8519, p≥0.031), Cd-Cr (r=0.9934, p≥0.000), and Pb-B (r=-0.9553, p≥0.003). In Damietta Harbor, the relationships of Zn-Pb (r=0.9456 p≥0.015), Zn-Cd (r=0.9406, p≥0.017), Cd-Pb (r=0.9924, p≥0.001), Zn-Ca (r=0.9024, p≥0.036), Zn-Mg (r=0.9241, p≥0.024), Zn-K (r=0.9487, p≥0.014), Pb-K (r=0.9218, p≥0.026), and Cd-K (r=0.9497, p≥0.013) are obtained. In Port Said, there are many correlations between Ni-Fe (r=0.9468, p≥0.015), Ni-Mn (r=0.9217, p≥0.026), Zn- Cu (r=0.9902, p≥0.001), Zn-Li (r=0.9349, p≥0.020), Cr-Na (r=0.9211, p≥0.026), Cd-Li (r=0.8879 p≥0.044), Cd-F (r=0.9355, p≥0.019), Cd-K (r=0.9673 p≥0.007), and Cd-Cl (r=0.8916 p≥0.042). The large amount of heavy metals may be related to the wastewater evacuation of phosphate fertilizers and untreated industrial pollutants, along with shipping activities. These correlations coincide with the high significant multiple regression equations (Table 5).
Table 5
Multiple regression analyses of heavy metals and different geochemical properties in the examined harbors
Harbor
|
Multiple regression equation
|
R
|
Sidi Krir
|
Fe = -191.7 + 0.40 Cr + 0.56 Mg - 0.15 Na
|
0.9998523
|
|
Mn = - 233.6 + 1.90 Cr - 0.48 Ni - 0.69
|
0.9996286
|
|
Zn = -38.22 + 1.07 Cd - 0.31 F + 0.14 B
|
0.9999672
|
|
Cu = 28.41 - 0.92 Na + 0.38 A% + 0.08 Ni
|
1.0000000
|
|
Ni = 3.96 - 0.94 Clay % + 0.11 Ca + 0.02 TP
|
1.0000000
|
|
Cr = 43.11 + 0.98 Fe - 0.18 F - 0.16 Sand %
|
0.9999997
|
|
Pb = 1.59 + 0.79 Na + 0.57 Zn - 0.14 Mg
|
0.9999990
|
|
Cd = 2.00 + 1.69 Li - 0.77 IP - 0.03 Fe
|
0.9999995
|
Dekhila
|
Fe = 12302.6 - 1.08 Sand % + 0.34 Ni - 0.11 SO4
|
0.9999345
|
|
Mn = - 30.65 + 1.28 Fe - 0.34 Pb + 0.11 SO4
|
0.9999979
|
|
Zn = - 95.73 + 0.56 Mean + 0.43 Pb + 0.13 TSiO3%
|
0.9999788
|
|
Cu = 42.63 - 0.93 F + 0.54 Cr + 0.19 Cd
|
0.9989686
|
|
Ni = 583.4 - 1.19 Cl + 1.02 A% + 0.73 Sand %
|
0.9999819
|
|
Cr
|
not significant
|
|
Pb = 5.38 + 1.27 Zn - 0.66 OP + 0.13 Cr
|
0.9999796
|
|
Cd = - 1.0 + 0.91 Ca + 0.19 Cu + 0.08 Cr
|
0.9999981
|
Western
|
Fe = 24718.2 - 1.01 K + 1.11 F - 0.73 Zn - 0.14 Silt %
|
0.9999497
|
|
Mn = 117.56 - 0.68 Cu + 0.57 Mean + 0.41 Fe + 0.14 IP
|
0.9999757
|
|
Zn = - 148.1 + 0.14 Na + 0.84 Tp - 0.39 B - 0.07 Cr
|
0.99999963
|
|
Cu = 702.0 - 0.97 Mn + 0.71 Mean + 0.43 Li + 0.29 Sorting
|
0.99998544
|
|
Ni = - 245.1 + 0.97 IP + 0.50 Mg + 0.26 Sorting + 0.11 A %
|
0.99999963
|
|
Cr = - 226.1 + 0.92 Cd + 0.20 Mn - 0.10 Cl + 0.05 Cu
|
0.99999998
|
|
Pb = 263.2 - 0.54 B + 0.48 Cr - 0.54 Li - 0.16 Zn
|
0.99999976
|
|
Cd = 12.5 + 1.08 Cr - 0.22 Mn + 0.11 C - 0.05 Cu
|
0.99999998
|
Dameitta
|
Fe = 9773.0 + 0.75 Cr + 0.59 TSiO3%
|
0.99511927
|
|
Mn = 518.2 + 0.87 OP + 0.20 Ca - 0.10 Clay %
|
0.99999726
|
|
Zn = 320.1 + 0.76 K - 0.77 IP + 0.62 A%
|
0.99997148
|
|
Cu = 22.3 + 0.96 Cd + 0.41 Cl - 0.25 Silt %
|
0.99996917
|
|
Ni
|
not significant
|
|
Cr = 368.5 - 1.23 Mean + 0.62 Mn + 0.10 F
|
0.99999789
|
|
Pb = 31.4 + 1.08 Cd - 0.14 A % - 0.02 F
|
1
|
|
Cd = - 2.12 + 0.93 Pb + 0.13 A % + 0.02 F
|
1
|
Port Said
|
Fe = 15733.2 + 1.08 Slt % - 0.0.09 Ca -0.06 Li
|
0.99999579
|
|
Mn = 1521.3 - 1.10 Sand % - 0.19 SO4 - 0.10 Sorting
|
0.99999988
|
|
Zn = - 25.0 + 0.96 Cu + 0.16 Fe - 0.06 Clay %
|
0.99999972
|
|
Cu = 16.9 + 1.04 Zn - 0.16 Fe + 0.07 Clay %
|
0.9999997
|
|
Ni = 73.4 + 1.13 Silt % - 0.31 SO4 + 0.06 OP
|
0.99999999
|
|
Cr = - 109.3 + 0.77 Na + 0.49 B - 0.17 Mean
|
0.99992905
|
|
Pb = 5.27 + 1.27 Cu - 0.60 Mean + 0.11 Na
|
0.99999901
|
|
Cd = 0.29 + 0.93 K + 0.22 OP + 0.13 Sand %
|
0.99999847
|
The cluster of heavy metals grouping and the geochemical parameters analyses also demonstrate the great coordination of these among themselves and with other parameters in each harbor (Fig. 2). The main processes affecting the distribution of heavy metals in sediments are dispersion, precipitation and sedimentation and chemical reactions (Amankwaa et al. 2021).
Principle component analysis (PCA) is applied to heavy metals and geochemical results to identify potential factors and sources of pollutants in sediments from the studied harbors (Amankwaa et al. 2021). Fig. 3 demonstrates loading factors for the various studied parameters including heavy metals to sediments in the harbors examined after Varimax rotation. The obtained PCs explain the different percentages of each harbor, reflecting the difference in sediment properties and the contributions of different heavy metals. In most harbors, the results identified two PCs of eigenvalues greater than 1, with the exception of Western Harbor displaying three PCs. About 73.45, 80.52, 86.07, 76.58 and 78.25% of the total variance in the sediments data sets represent the Sidi Krir, Dekhila, Western, Damietta and Port Said harbors respectively.
Box Whisker plots for the various detected heavy metals (Fe, Mn, Zn, Cu, Ni, Cr, Pb and Cd) in the sediments of the investigated harbors are represented (Fig. 4). However, the box represents the minimum (Q0 or 0%, lowest data point excluding any outliers), maximum (Q4 or 100%, highest data point excluding any outliers), Median (Q2 or 50%, the middle value of the dataset of each heavy metal. First quartile (Q1 or 25%, the lower quartile) is the median of the lower half of the dataset. Third quartile (Q3 or 75%, the upper quartile) is the median of the upper half of the dataset. Box Whisker plot for Sdi Krir Harbor shows great variability in Fe, Mn, Zn, and Cu contents. Amongst the studied heavy metals, Fe concentration varies greatly along the sediments of Sidi Krir, Dekhila, and Western harbors.
Pollution and ecological indices
Enrichment factor ( EF )
The enrichment factor using the median background of the studied heavy metals in each harbor values gives minimal enrichment for all the determined elements. (EF < 2; Khalil et al. 2016).
Geo-accumulation index ( Igeo )
Almost all harbors examined show that 100% of their stations are uncontaminated by all examined heavy metals (Igeo≤0), except for Cd (Table 6). Cd appears to contribute significantly to the sediment pollution in all stations in the studied harbors and IgeoCd ranges from moderately to severe to severely polluted. High IgeoCdvalues are observed in the sediments at Dekhila, Western, Damietta and Port Said harbors.
Table 6
Overall pollution status using different risk indices in each of the studied harbors
Risk indices
|
Sidi Krir
|
Dekhila
|
Western
|
Dameitta
|
Port Said
|
Most polluted station
|
Overall pollution status
|
EFFe
|
0.35-1.00
|
0.40-1.00
|
0.47-0.95
|
0.92-1.00
|
0.79-1.00
|
|
No enrichment
|
EFMn
|
0.13-1.00
|
0.36-1.00
|
0.48-0.99
|
0.39-1.00
|
0.27-1.00
|
|
No enrichment
|
EFZn
|
0.09-1.00
|
0.44-1.00
|
0.29-0.91
|
0.76-1.00
|
0.32-1.00
|
|
No enrichment
|
EFCu
|
0.17-1.00
|
0.00-1.00
|
0.41-0.94
|
0.73-1.00
|
0.07-1.00
|
|
No enrichment
|
EFNi
|
0.81-1.00
|
0.06-1.00
|
0.43-0.89
|
0.64-1.00
|
0.30-1.00
|
|
No enrichment
|
EFCr
|
0.82-1.00
|
0.09-1.00
|
0.03-0.84
|
0.84-1.00
|
0.32-1.00
|
|
No enrichment
|
EFPb
|
0.16-1.00
|
0.14-1.00
|
0.08-0.71
|
0.52-1.00
|
0.12-1.00
|
|
No enrichment
|
EFCd
|
0.57-1.00
|
0.26-1.00
|
0.41-0.89
|
0.30-1.00
|
0.43-1.00
|
|
No enrichment
|
Igeo Fe
|
-ve
|
-ve
|
-ve
|
-ve
|
-ve
|
|
Unpolluted
|
Igeo Mn
|
-ve
|
-ve
|
-ve
|
-ve-0.25
|
-ve-0.31
|
Stations 20, 22, 24, and 26
|
Unpolluted to moderately polluted
|
Igeo Zn
|
-ve
|
-ve
|
-ve-0.61
|
-ve
|
-ve
|
Station 11-14, and 16
|
Unpolluted to moderately polluted
|
Igeo Cu
|
-ve
|
-ve
|
-ve-3.08
|
-ve
|
-ve
|
Station 11, 13 and 14
|
Unpolluted to strongly polluted
|
Igeo Ni
|
-ve
|
-ve-1.46
|
-ve
|
0.76-1.23
|
0.03-1.01
|
Stations 7, and 17- 26
|
Unpolluted to moderately polluted
|
Igeo Cr
|
-ve
|
-ve
|
-ve-1.86
|
-ve
|
-ve-0.22
|
Station 16 and 26
|
Unpolluted to moderately polluted
|
Igeo Pb
|
-ve
|
-ve-0.10
|
-ve-2.44
|
-ve-2.22
|
-ve-0.74
|
Stations 10, 12, 14, 16, 18, 22 and 23
|
Unpolluted to moderately polluted
|
Igeo Cd
|
2.69-3.72
|
3.14-4.47
|
3.82-7.06
|
2.23-5.32
|
2.74-3.90
|
All stations
|
Moderately to strongly polluted to Extremely polluted
|
CFFe
|
0.00-0.01
|
0.15-0.29
|
0.18-0.32
|
0.48-0.51
|
0.43-0.50
|
All stations
|
No contamination
|
CFMn
|
0.00-0.05
|
0.20-0.38
|
0.29-0.49
|
0.77-1.78
|
0.85-1.86
|
Stations 17-18, 20-24, and 26
|
No to moderate contamination
|
CFZn
|
0.03-0.45
|
0.45-1.44
|
1.05-2.29
|
0.69-1.06
|
0.50-1.09
|
Stations 8, 10-16, 18, and 23
|
No to moderate contamination
|
CFCu
|
0.29-1.13
|
0.04-0.63
|
0.95-12.67
|
0.41-0.72
|
0.09-0.77
|
Stations 11
|
No to very high contamination
|
CFNi
|
0.04-0.06
|
0.04-2.75
|
0.05-0.94
|
1.70-2.34
|
1.02-2.01
|
Stations 7,18,20, 21 and 26
|
Moderate contamination
|
CFCr
|
0.035-0.04
|
0.04-0.46
|
0.04-5.45
|
0.79-0.98
|
0.74-1..75
|
Station 16, 22-23, and 25-26
|
No to very high contamination
|
CFPb
|
0.27-0.92
|
0.33-2.06
|
1.03-10.39
|
0.68-8.92
|
0.27-3.21
|
Station 8, 10-16, 18, and 22-23
|
No to very high contamination
|
CFCd
|
9.65-19.79
|
13.21-33.34
|
13.21-199.90
|
7.06-59.75
|
10.00-22.33
|
All stations
|
very high contamination
|
Cd
|
10.82-21.90
|
15.04-35.88
|
33.92-219.23
|
12.79-75.03
|
14.44-31.92
|
All stations
|
moderate dgree to very high degree of contamination
|
mCd
|
1.35-2.74
|
1.88-4.48
|
4.24-27.40
|
1.60-9.38
|
1.80-3.99
|
Stations 7-16, 17-18, 19-24, and 26
|
low degree of contamination to extremely high degree of contamination
|
PLI
|
0.09-0.19
|
0.30-0.88
|
0.89-1.86
|
0.98-2.12
|
0.70-1.59
|
Station 18
|
Unpolluted to Heavily polluted
|
PLIs
|
0.13
|
0.54
|
1.19
|
1.27
|
1.24
|
Western, Damietta, and Port Said
|
No to progressive deterioration
|
RI
|
297.8-963.9
|
234.6-1852.9
|
411.9-6054.1
|
234.6-1852.9
|
269.4-466.8
|
Station 15
|
High to very high risk
|
TRIZn
|
0.02-0.36
|
0.36-1.15
|
0.84-1.82
|
0.55-0.84
|
0.40-0.87
|
Station 13
|
No toxic risk
|
TRICu
|
0.77-3.04
|
0.12-1.68
|
2.55-34.04
|
1.11-1.94
|
0.25-2.08
|
Station 11
|
Very high toxic risk
|
TRINi
|
0.15-0.20
|
0.16-9.78
|
0.18-3.36
|
6.04-8.32
|
3.64-7.15
|
Station 7
|
Low toxic risk
|
TRICr
|
0.05-0.06
|
0.06-0.66
|
0.06-7.75
|
1.13-1.39
|
1.05-2.48
|
Station 16
|
Low toxic risk
|
TRIPb
|
0.08-0.28
|
0.10-0.62
|
0.31-3.15
|
0.21-2.70
|
0.08-0.97
|
Station 16
|
No toxic risk
|
TRICd
|
1.73-3.55
|
2.37-5.98
|
3.79-35.84
|
1.27-10.71
|
1.79-4.00
|
Station 16
|
Very high toxic risk
|
∑TRI
|
2.93-6.06
|
3.53-15.59
|
10.98-49.60
|
10.78-23.48
|
7.93-15.76
|
All stations, except stations 2-3, and 5-6
|
No toxic risk to very high toxic
|
TUs
|
0.76-1.52
|
1.02-6.22
|
3.47-13.20
|
4.62-8.13
|
3.27-6.15
|
Stations 7, 11, 13, 14, 16-24 and 26
|
No toxic risk to more than moderate toxic ecosystem
|
m-ERM-Q
|
0.07-0.13
|
0.09-0.92
|
0.29-1.04
|
0.63-0.96
|
0.42-0.77
|
Station 16
|
Most stations are of 21% being biotoxic
|
m-PEL-Q
|
0.12-0.25
|
0.17-0.92
|
0.57-2.20
|
0.70-1.27
|
0.50-0.95
|
Station 16
|
Rang from 9–21% being bio toxic
|
HQsedZn
|
0.03-0.46
|
0.46-1.48
|
1.08-2.34
|
0.71-1.08
|
0.51-1.12
|
Station 13
|
No to moderately hazards
|
HQsedCu
|
1.07-4.24
|
0.17-.2.34
|
3.55-47.43
|
1.55-2.71
|
0.35-2.90
|
Station 11
|
Potentail to very high hazards
|
HQsedNi
|
0.20-0.27
|
0.21-12.96
|
0.24-4.45
|
8.01-11.03
|
4.83-9.48
|
Station7
|
Potentail to very high hazards
|
HQsedCr
|
0.07-0.08
|
0.08-0.89
|
0.1-10.42
|
1.51-1.87
|
1.41-3.34
|
Station 16
|
Potentail to high hazards
|
HQsedPb
|
0.11-0.38
|
0.14-0.85
|
0.42-4.30
|
0.28-3.69
|
0.11-.33
|
Station 16
|
Potentail to moderate hazards
|
HQsedCd
|
2.13-4.37
|
2.91-7.36
|
4.66-44.10
|
1.56-13.18
|
2.21-4.92
|
Station 16
|
Moderate to high hazards
|
mHQsedZn
|
0.21-0.86
|
0.86-1.54
|
1.32-1.94
|
1.07-1.32
|
0.91-1.34
|
station 13
|
No low to moderate severity of contamination
|
mHQsedCu
|
1.20-2.39
|
0.47-1.77
|
2.18-7.98
|
1.44-1.91
|
0.69-1.97
|
station 11
|
No to extreme severity of contamination
|
mHQsedNi
|
0.56-0.65
|
0.58-4.53
|
0.62-2.66
|
3.56-4.18
|
2.76-3.87
|
station 7
|
Very low to extreme severity of contamination
|
mHQsedCr
|
0.35-0.38
|
0.38-1.26
|
0.39-4.33
|
1.65-1.84
|
1.59-2.45
|
Station 16
|
No to extreme severity of contamination
|
mHQsedPb
|
0.39-0.73
|
0.43-1.09
|
0.77-2.45
|
0.63-2.27
|
0.39-1.36
|
Station 16
|
No to considerable severity of contamination
|
mHQsedCd
|
1.62-2.32
|
1.89-3.01
|
2.39-7.36
|
1.38-4.03
|
1.65-2.46
|
Station 16
|
Low to extreme severity of contamination
|
Contamination factor ( CF ), contamination degree ( Cd ) and modified degree of contamination ( mCd )
The CF of all the heavy metals studied in the harbors examined reflects that Fe is the only heavy metal showing a low level of contamination (CFFe < 1), while Cd shows the very high contamination (CFCd > 6) (Table 6). Most of the Damietta (sties: 17-18 and 20-21; 80% of sites) and Port Said (sites: 22-24 and 26; 80% of sites) harbors stations suffer moderately from Mn pollution (1<CFMn<3), while three other harbors examined have low Mn contamination (CFMn< 1). Most the stations studied in the examined harbors give CFZn values of low contamination level (CFZn< 1), except for Western Harbor sites showing moderate zinc contamination (1<CFZn<3). Half of Western Harbor sites have moderate Cu contamination (sites 13-15; 1<CFCu<3), while site 11 shows the highest percentage of Cu contamination (CFCu> 6) among the sites examined. Almost of the stations in inspected harbors have low Ni contamination (CFNi < 1) with the exception of site 7 in Dekhila and sites 17-21 in Damietta (100% of sites) and sites 22-24 and 26 in Port Said harbor (80% of sites) which show medium Ni pollution (1< CFNi <3). Almost all harbor stations give a low degree of Cr contamination (CFCr <1), except for station 16 (Western Harbor), and stations 22, 23, 25 and 26 (Port Said) are affected by moderate Cr pollution (1<CFCr<3). Western Harbor is the most Pb contaminated site, however, half of the sites (sites: 23, 14 and 16) show CFCu> 6, along with station 18 (Damietta Harbor), while the other sites range from low to Pb contamination. The Cd and mCd values reflect that the harbors range from low to very high pollution areas. The Cd values are taken in descending order for Western Harbor (33.9-219.0)> Damietta Harbor (12.8-75.0)> Dekhila (15.0-35.9)> Port Said (14.4-31.9.2)> Sidi Krir (10.8-21.9). The mCd values are taken in descending order: Western Harbor (4.2-27.4)> Damietta Harbor (1.6-9.4)> Dekhila (1.9-4.5)> Port Said (1.8-4.0)> Sidi Krir (1.4-2.7).
Pollution load index ( PLI )
The PLI values are calculated for stations at each harbor and for each harbor zone (Ganugapenta et al. 2018). The PLI values range from unpolluted (<0.7) especially along Sidi Krir and Dekhila to heavily polluted (<3) at Damietta Harbor (St 18); Fig. 5) The PLI for the zone gives the decreasing order: Damietta (1.27)> Port Said (1.24)> Western (1.19) > Dekhila harbors (0.54)> Sidi Krir (0.13) (Table 6 and Fig. 5 ), pointing out that the Western, Damietta and Port Said harbors are the most affected by heavy metal areas along the other harbors that were examined (exceed the baseline of pollutants>1) (Goher et al. 2014).
Toxic risk index ( TRI ) and integrated TRI (∑TRI)
The high TRICu, TRINi and TRICd values distinguished in the investigated harbors refer to the industrial and other anthropogenic sources, especially in Western and Damietta harbors (Table 6 and Fig. 5). It was reported that Cu, Ni and Cd are obtained from anthropogenic activities (Al Naggar et al. 2018). Almost all the stations along the studied harbors range from low (∑TRI<5) to very high toxic (∑TRI> 20) (Table 6 and Fig. 5). The high ∑TRI values recorded in Western, Damietta and Port Said harbors reflect that these harbors are of considerable and very high toxic risk.
Toxic units ( TUs ) and sum of toxic units (∑TUs)
The TUs and ∑TUs of each heavy metal and studied harbor are illustrated (Fig. 5). Most of the studied sites (sites 7, 11, 13, 14, 16-24 and 26) show that ∑TUs exceed 4 amount for the moderate toxicity, i.e. significant mortality can be observed (Zhang et al. 2016). Higher values of TUNi (sites 7, and 17-26) and TUCu (site 11) along the investigated region may be associated with the significant environmental toxicity contribution due to the liquid hydrocarbons' sources and cargo activity (Yee 2010). The higher TUCd values shown for Damietta and Port Said harbors probably reflect the oil pollution from the shipping activities and oil refining and gas liquefaction and other petrochemical industrial projects (El-Asmar et al. 2014; Al Naggar et al. 2018).
Mean ERM ( m-ERM-Q ) and mean PEL ( m-PEL-Q ) quotients
Amongst the harbors studied, Sidi Krir shows the lowest quotient values of m-ERM-Q (0.07-0.13) and m-PEL-Q (0.12-0.25), representing 9–21% being bio toxic with least potential adverse effects marine on the environment (Table 6). Given the m-ERM-Q values, most of the stations in the harbors examined have 21% of adverse biotoxic effects on the marine ecosystem, whereas, the high m-PEL-Q quotients reflect that about 49% of the potential biotoxicity may occur in Damietta and Port Said harbors. The variability of biotoxicity from one harbor to another may be related to the sediment texture; i.e., the high sediment contamination with heavy metals especially in silty clay sediments as previously reported (Long et al. 2000). However, the highest m-ERM-Q and m-PEl-Q quotients are recorded in the harbors of lower carbonate and higher sand, silt and clay % (Table 3).
Sediment modified hazard quotient ( mHQsed )
According to the mHQsed, Western Harbor is shown to be highly hazardous for contamination (2.5> mHQsed> 3) with values of Cu, Ni, and Cd (Table 6). The harbors of Damietta and Port Said show severe Ni contamination (mHQsed> 3.5) and for other metals it ranges from low (mHQsed< 0.5) to moderate contamination (1.5> mHQsed> 2).
Sediment hazard quotients ( HQsed )
In Table 6, along the harbors studied, most stations in Western Harbor range from medium to high risk with Cu (3.5-47.4), Pb (0.4-4.3) and Cd (4.7-44.1), except Cr which gives HQsed values (0.1-10.4) that ranges from potential to high risk. Stations in the harbors of Damietta (HQsedNi; 8.0-11.0) and Port Said (HQsedNi; 4.8-9.5) exhibit moderate Ni risks, while only station 7 at Dekhila Harbor gives high risk with Ni (HQsedNi= 13.0) .
Human health risk assessment
The CDI values presented for specific heavy metals for children are higher than those for adults along the studied area due to the same consumption of heavy metals for child, lower exposure time and lower body weight resulting in higher CDI values. For Fe, the chronic daily intake (CDIFe) of the child (5.3E-03- 5.1E-01, av. 2.9E-01 mg/Kg-day) and adult (2.3E-04- 2.2E-02, av. 1.2E-02 mg/Kg-day) in the harbors studied. The CDIFe takes a child and adult in the order of harbors: Damietta (5.1E-01 and 2.2E-02, respectively)> Port Said (4.8E-01 and 2.1E-02, respectively)> Western (2.6E-01 and 1.1E-02, respectively)> Dekhila (2.4E-01 and 1.0E-02, respectively)> Sidi Krir (5.3E-03 and 2.3E-04, respectively) considering that the chronic toxicity of oral sediment ingestion to adults in all harbors causes no hemosiderosis and cirrhosis symptoms (0.7-1.4 mg/Kg-day) (USEPA 2006). All other harbors (CDIFe) for adults appear lower than those reported in dietary intake and biochemical indices for adult (0.15-0.27 mg/Kg-day) (USEPA 2006). For Mn, the chronic daily intake (CDIMn) of the child (4.6E-04-3.0E-02, av. 1.4E-02 mg/Kg-day) and adult (2.0E-05-1.3E-03, av. 6.2E-04 mg/Kg-day) in the harbors studied is less than tolerable upper intake level for adult age ≥ 19 years (11 mg/Kg-day) (ATSDR 2012a). (CDIZn) of children and adults is lower than those recorded for gastrointestinal symptoms (0.16 and 0.05 mg/Kg-day) (ATSDR 2005a). For Cu, CDICu shows lower than reported for no-observed-adverse-effect level (NOAEL, 0.0272 mg/Kg-day) and lowest-observed-adverse effect level (LOAEL, 0.0731 mg/Kg-day) causing increased nausea vomiting, and/or abdominal pain. Based on the appropriate daily nickel dose recorded for food using a 70 Kg body weight reference (0.0024 mg/Kg-day) (ATSDR 2005b), the CDINi harbors values have leaser values for Ni toxicity. CDICr for child and adult along the harbors also sets lower values than those reported for oral chromium (VI) compounds intermediate duration (MRL, 0.005 mg/Kg-day) (ATSDR 2008). The CDIPb for children and adults along the harbors studied are of higher values than those reported for the Pb reference dose (RFD of tetraethyl lead, 1X10−7 mg/Kg-day) (ATSDR 2020) that may pose health risks. All CDIPb values for children (2.1E-04 - 1.9E-03 mg/Kg-day) and adults (9.2E-06 - 8.2E-05 mg/Kg-day) belonging to the harbors examined have values lower than those specified for lead toxicity (ATSDR 2020). CDICd values for children (av. 1.2E-04 mg/Kg-day) and adults (av. 5.2E-06 mg/Kg-day) show lower amounts than those recorded for renal system toxicity symptoms (2.1E-03 mg/Kg-day) (ATSDR 2012c).
HQ values of children are higher than those for adults and show amounts of less than 0.2, reflecting no risk of ingestion and dermal contact with sediment (Fig. 6). THQ values appear approximately below unity except for the harbors of Western (2.6), Port Said (2.5), and Damietta (2.3). Non-carcinogenic hazard risk index (HI) for children and adults shows amounts more than unity and the harbors are said to be not polluted with heavy metals, except for children in the Western (3.2), Port Said (2.9), Damietta (2.6) harbors (Fig. 7). Non-carcinogenic hazard risk index (HI) values along the harbor take the order: Western> Port Said> Damietta> Dekhila> Sidi Krir.
CTR Ing and CTRDerm values for children and adults show values beyond 1.0E-04 (Figure 7). Also, TLCR values for children and adults indicate the non-uniformly high abundance of heavy metals in the harbors sediments that possibly cause adverse public health effects. This explores that it is necessary to monitor heavy metals involving many industries, agriculture, and wastewaters for exposure risks.