Biological Evidence 2018, Vol.8, No.3, 21-31
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Table 4 Contamination factor, degree of contamination and pollution load index of the heavy metal concentration in sediment of Nun
River at Gbarantoru and Tombia towns in Bayelsa state, Nigeria
Parameters
Median mean
Geometric mean
Contamination factor
Location A
Location B
Location C
Location A Location B
Location C
Cd
1.091
1.000
0.455
1.500
1.375
0.625
Cr
1.500
1.000
0.500
1.500
1.000
0.500
Co
2.000
1.000
1.000
2.000
1.000
1.000
Ni
2.667
1.000
0.083
4.000
1.500
0.125
Pb
1.308
1.000
0.538
1.417
1.083
0.583
Zn
1.145
1.000
0.745
1.212
1.053
0.788
Fe
1.271
1.000
0.559
1.427
1.122
0.627
Comparison criteria
Note: CF < 1 (low contamination); 1 ≤ CF <3 (moderate contamination); 3 ≤ CF < 6 (considerable
contamination); CF ≥ 6 (very high contamination)
Degree of contamination 10.982
7
3.88
13.056
8.133
4.248
Comparison criteria
Note: CD<8 (Low risk); 8 ≤ CD<16 (Moderate risk); 16 ≤ CF<32 (Considerable); CD>32 (Very high)
Pollution load index
1.494
1.000
0.458
1.718
1.149
0.527
Comparison criteria
Note: PLI < 1 (no pollution); 1< PLI< 2 (moderate pollution); 2< PLI< 3 (heavy pollution); 3 <PLI
(extremely heavy pollution)
The degree of contamination of heavy metals in the sediment ranged from low risk (CD<8) to moderate risk (8 ≤
CD<16). The results showed that location A had higher risk compared to locations B and C. This is an indication
of varying effects of anthropogenic activities in the different locations. The pollution load index of heavy metals
in the sediment was within no pollution (for location C) to moderate pollution (for location A and B). This give
overall information that location A and B is more polluted compared to location C under both background
considerations. The trend reported in both scenarios had some similarity with the work of Bhutiani et al. (2017),
Izah et al. (2017d).
The Index of geo-accumulation of heavy metals in sediment of Nun River at Gbarantoru and Tombia towns in
Bayelsa state is presented in Table 5. Under both considerations (median and geometric mean), the index of
geo-accumulation were un-contamination (Igeo≤0) except for nickel for location A under geometric mean scenario
that were moderately contaminated. The trend reported for both scenarios has some similarity with the work of
Bhutiani et al. (2017), Izah et al. (2017c). From the result of contamination factor and negative geo-accumulation
index it suggests that instances of the heavy metals contamination in the sediment of the river is from
anthropogenic sources (Izah et al., 2017c).
Table 5 Geo-accumulation index of the heavy metals concentration in sediment of Nun River at Gbarantoru and Tombia towns in
Bayelsa state, Nigeria
Parameters
Median mean
Geometric mean
Igeo
Location A
Location B
Location C
Location A
Location B
Location C
Cd
-0.502
-0.628
-1.766
0.000
-0.125
-1.262
Cr
0.000
-0.584
-1.586
0.000
-0.584
-1.586
Co
0.000
-1.000
-1.000
0.000
-1.000
-1.000
Ni
-0.234
-0.584
-4.158
1.415
0.000
-3.591
Pb
-0.234
-0.621
-1.515
-0.083
-0.470
-1.362
Zn
-0.388
-0.584
-1.009
-0.308
-0.504
-0.927
Fe
-0.241
-0.584
-1.427
-0.071
-0.419
-1.258
Comparison criteria
Igeo ≤ 0 (uncontaminated), 0<Igeo ≤ 1 (uncontaminated to moderately contaminated), 1< Igeo ≤ 2
(moderately contaminated), 2 < Igeo < 3 (moderately to heavily contaminated), 3< Igeo < 4 (heavily
contaminated), 4 < Igeo < 5 (heavily to extremely contaminated), Igeo ≥ 5 (extremely contaminated)
Table 6 presents the quantification of contamination (QoC) of heavy metals in sediment of Nun River in Bayelsa
state, Nigeria. In location A, all the heavy metals under study showed positive quantification values in both
