Bioscience Methods 2017, Vol.8, No.1, 1-18
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Figure 2 presents the pollution load index of heavy metals concentration in cassava mill effluents contaminated
soil. Pollution load index showed that LC in both seasons is moderately polluted, while wet season in LB and CE
and dry season in LD showed moderate pollution under BMM consideration. While in BGM scenario, wet season
in LB and LE and dry season of LC and LD also showed moderate pollution as well. The trend in both
background level of this study is similar to findings of Bhutiani et al. (2017). This is also an indication that the
level of pollution is affected by seasons as well as spatial distribution within the cassava mill effluents
contaminated soil.
Figure 2 Pollution load index of heavy metals concentration in cassava mill effluent contaminated soil
Note: PLI < 1 (no pollution); 1< PLI< 2 (moderate pollution); 2< PLI< 3 (heavy pollution); 3 <PLI (extremely heavy pollution)
BMM- Background Median Mean; BGM- Background Geometric Mean
The statistical analysis of Pollution index of heavy metals concentration in cassava mill effluents contaminated
soil is presented in Table 5 The mean value of all the heavy metals in both seasons under both background
scenarios ranged from no pollution (P1≤1) to low pollution (1<PI≤2). Under BMM scenario, copper, iron, lead,
cadmium and chromium in both seasons, and nickel and cobalt in wet season showed low pollution, while the
other heavy metals indicate no pollution. While in BGM consideration scenario, there was low pollution in all the
metals under study across both seasons of study. This is an indication that pollution resulting from cassava mill
effluent in small scale processing in rural community in the Niger Delta is low.
Table 5 Statistical analysis of pollution index of heavy metals concentration in cassava mill effluent contaminated soil
Parameters
Season
BMM
BGM
Min
Max
Mean
Min
Max
Mean
Cu
Dry
0.51
1.72
1.08
0.52
1.75
1.10
Wet
0.86
1.25
1.06
0.82
1.19
1.01
Zn
Dry
0.22
1.14
0.86
0.30
1.53
1.15
Wet
0.47
1.23
0.92
0.54
1.40
1.05
Mn
Dry
0.47
1.41
0.90
0.57
1.70
1.09
Wet
0.47
1.36
0.96
0.52
1.50
1.06
Fe
Dry
0.40
1.62
1.01
0.46
1.85
1.16
Wet
0.80
1.26
1.04
0.78
1.23
1.02
Pb
Dry
0.31
2.02
1.15
0.34
2.20
1.26
Wet
0.42
4.34
1.60
0.36
3.70
1.36
Cd
Dry
1.00
1.00
1.00
1.00
1.00
1.00
Wet
1.00
2.09
1.41
0.77
1.60
1.08
Cr
Dry
0.18
1.83
0.97
0.23
1.43
1.26
Wet
0.74
2.82
1.33
0.64
2.44
1.23
Ni
Dry
0.71
1.58
1.13
0.75
1.48
1.06
Wet
0.64
3.53
1.60
0.50
2.76
1.25
Co
Dry
0.32
1.09
0.85
0.41
1.39
1.09
Wet
1.00
2.13
1.39
0.76
1.63
1.06
Note: PI≤1 (No pollution); 1<PI≤2 (Low pollution); 2<PI≤3 (Moderate pollution); 3<PI≤5(High/strong pollution); PI≥5 (Very
high/strong pollution); BMM- Background Median Mean; BGM- Background Geometric Mean
0
0.5
1
1.5
Dry Wet Dry Wet Dry Wet Dry Wet Dry Wet
LA
LB
LC
LD
LE
Locations
BMM
BGM
