International Journal of Marine Science 2016, Vol.6, No.26, 1-13
8
Table (3): Concentration of heavy metals and values of contamination factor (CF) in bivalve
B. variabilis
collected from northern
part of theGulf of Suez during 2014-2015.
Metals
Stations
Summer
Winter
Mean±SD
CF
Cd
St. 1
St. 2
St. 3
St. 4
St. 5
St. 6
St. 7
0.29±0.06
NF
0.26±0.03
0.56±0.00
0.34±0.09
0.18±0.02
0.19±0.02
0.33±0.07
NF
0.17±0.02
0.29±0.07
0.20±0.03
0.19±0.21
0.21±0.02
0.31±0.06
NF
0.22±0.05
0.40±0.15
0.27±0.10
0.19±0.14
0.20±0.02
1.63
NF
1.16
2.11
1.42
1.00
1.05
Pb
St. 1
St. 2
St. 3
St. 4
St. 5
St. 6
St. 7
0.53±0.35
NF
0.82±0.40
2.02±0.83
2.54±0.47
1.74±0.13
1.59±0.62
1.43±0.17
NF
0.97±0.14
0.81±0.20
0.85±0.28
1.05±0.18
1.47±0.20
1.02±0.53
NF
0.89±0.30
1.33±0.82
1.70±0.97
1.39±0.39
1.54±0.46
1.15
NF
1.00
1.49
1.91
1.56
1.73
Cu
St. 1
St. 2
St. 3
St. 4
St. 5
St. 6
St. 7
3.69±0.34
NF
2.18±0.55
2.72±0.88
2.22±0.38
2.56±0.47
3.29±0.25
4.38±0.54
NF
2.73±0.25
3.72±0.78
2.59±0.41
2.82±0.83
2.11±0.05
4.06±0.56
NF
2.45±0.49
3.29±0.92
2.40±0.42
2.69±0.65
2.77±0.65
1.69
NF
1.02
1.37
1.00
1.12
1.15
Zn
St. 1
St. 2
St. 3
St. 4
St. 5
St. 6
St. 7
12.36±1.61
NF
9.35±1.14
17.04±2.08
13.74±1.96
9.29±1.34
9.98±1.33
15.93±1.03
NF
9.97±0.71
16.02±2.21
10.23±0.72
8.12±1.60
10.35±0.58
14.30±2.24
NF
9.66±0.95
16.46±2.04
11.99±2.31
8.70±1.52
10.14±1.03
1.64
NF
1.11
1.89
1.38
1.00
1.17
NF: Not found
4.3 Assessment of heavy metals contamination
In the interpretation of the present obtained data, choice of background values plays a significant contribution.
Several researchers have used the average shale values or the average crustal abundance data as reference
baselines for sediment samples, these values are 0.1, 14.8, 25 and 52 µg/g for Cd, Pb, Cu and Zn, respectively
(Wedepohl, 1995; Loska and Danuta, 2003 and Islam
et al
., 2015). While for bivalve
B. variabilis
, the lowest
mean values in the present study were used as baseline concentrations. The degree of contamination from heavy
metals could be evaluated by determining the contamination factor (CF), pollution load index (PLI) and metal
pollution index (MPI) from the following formulae 1, 2 and 3 [Tomlinson
et al
., 1980 and Usero
et al
., 2005].
The ratio of the measured concentration to natural abundance of a given metal had been proposed as the
contamination factor (CF); thus, the CF values can monitor the enrichment of one given metal in sediments over a
period of time. The obtained data for CF in sediments and bivalve species showed the range of 0.14 - 24.60 and
1.00 – 2.11, respectively, with high value for Cd (15.90 - 24.60) in sediments samples. Harikumar and Jisha
(2010) stated that CF < 1 refers to low contamination, 1 ≥ CF ≥ 3 means moderate contamination, 3 ≥ CF ≥ 6
