International Journal of Marine Science, 2017, Vol.7, No.13, 114-124
120
Continued Table 4
Location
Cu
Zn
Pb
Cd
Fe
Mn
Ni
Co
References
Red Sea coastal
area
22.1-106.8 24.9-174.2 30.9-76.1 1.9- 5.1
3324 -
19296
129.8-536.7 18.3-58.9 13.6-20.4 present study
Red
Sea
background
17.6
24
3
0.4
3000
116
16
3
Hanna, 1992
Average Shale
45
95
20
0.3
850
68
19
Forstner and
Wittmann,
1979
2.2 Correlations between metals and PCA
The correlation matrix (Table 5) showed that a strong significant positive correlation (0.76 < r < 0.84) was
obtained between metal pairs Zn, Cu and Pb, as well as between Fe and Mn. The levels of Ni also correlated
significantly with Zn (r=0.59), Fe (r=0.55) and Mn (r=0.63). The correlation between metals in surface sediments
usually related to discharging of contaminants and their effect on partitioning of metals in aquatic system and may
be influenced by differences in physical, chemical and biological processes in aquatic environment (Usman et al.,
2013).
Table 5 The correlation coefficient among heavy metals in sediments
Cu
Zn
Pb
Cd
Fe
Mn
Ni
Co
Cu
1.00
Zn
0.84**
1.00
Pb
0.77**
0.78**
1.00
Cd
0.32
0.45
0.34
1.00
Fe
0.26
0.33
0.04
0.20
1.00
Mn
0.18
0.32
0.18
0.11
0.76**
1.00
Ni
0.37
0.59**
0.44
0.42
0.55**
0.63**
1.00
Co
-0.10
0.03
-0.09
0.12
0.48
0.29
0.26
1.00
Note: ** Two-tailed correlation significant at p˂0.01
Principal component analysis (PCA) was performed to elucidate potential sources of metals in the present study.
The results showed two principal components with eigenvalues ˃ 1; they accounted for 67.27% of the total
variance. Factor one (accounting for 42.05%) grouped Cu, Zn, Pb and Ni. As shown in PCA bi -plot (Figure 3), the
sites associated with this factor were mainly those which experienced sever maritime activities (H2, S2) which
suggest the anthropogenic sources of these metals. The second factor (accounting for 25.22% of total variance)
grouped Fe, Mn and partially Co. The spatial distribution of these metals was related to locations of Qusier and
Safaga Cities. On the other hand, the reference location and Ras Gharib locations were in the fourth quarter of the
bi-plot which indicates relatively low contribution of heavy metals (Figure 3).
Figure 3 Principal component bi-plot showing variables and sampling locations
