EIA REVALIDATION FOR FORCADOS-YOKRI INTEGRATED PROJECT (NAG WELLS)
Microbiology
Total Heterotrophic Bacteria (THB) counts ranged from 1.0 to 3.0 x 102 cfu/ml, Total Fungi (TF) ranged from 0 to 1.05 x 102 cfu/ml. THB and TF did not show any significant difference between project area and control. According to Omiema and Ideriah (2012) viable bacteria in overlying water are typically about 106 and 107 cells per ml. For sea water, bacteria numbers generally range from 103 to 106 per ml (Azam et al., 1983). Bacterial abundance is also related to the organic matter concentration and to hydrological phenomena (Azam et al., 1983). The counts of bacteria and fungi were generally low which may be attributed to low levels of organic carbon and nutrients in the water. Hydrocarbon Utilizing Bacteria (HUB) and Hydrocarbon Utilizing Fungi (HUF) were not observed in the project area and control. The distribution of hydrocarbon-utilizing microorganisms is known to reflect the historical exposure of the environment to hydrocarbons (Atlas and Barth a, 1972). Absence of HUB and HUF are indicators of unpolluted environment with respect the petroleum hydrocarbons.
EIA REVALIDATION FOR FORCADOS-YOKRI INTEGRATED PROJECT (NAG WELLS)
Parameters
Baseline
2001 2012 Dry 2012 Wet 2018 Wet
2018 Contr ol
P Valu es Demand
(BOD), mg/l Chemical Oxygen Demand (COD), mg/l
104.69a±6
4.79 9.14a±2.58 7.91a±2.09 14.35a±3.57
12.92 a
0.00 0
Total Dissolved Solids (TDS), mg/l
7891c±409 0
7189.76b±17 12.78
5813.8b±238 0.22
14156a±7357.6 6
9311.
5b
0.00 0
Total Suspended solids (TSS), mg/l
24.88a±23.
06 8.19b±1.51 8.97b±0.75 27.9a±6.7 25.1a
0.00 0
Colour,
Pt.Co. 36.25±11.09 40
0.62 3
Odour 0
Alkalinity,
mg/l 429.96±25.82
319.9
7 0.24
Appearance 0
Nitrate, mg/l 0.74b±0.3 10.83a±4.94 2.72b±1.94 0.56b±0.05 0.55b 0.00 0 Phosphorus,
mg/l 0.50b±0.24 1.24a±0.77 0.05b±0.04 0.05b±0.051 0.02b 0.00 0 Carbonate,
mg/l <0.001±0 <0.001±0 <0.02±0 0
0.00 0
Salinity, oo/o 20.03±11.06 12.4
0.35 5 Redox
potential
(±mV) 172.3±24.53
185.4 5
0.06 4
EIA REVALIDATION FOR FORCADOS-YOKRI INTEGRATED PROJECT (NAG WELLS)
Parameters
Baseline
2001 2012 Dry 2012 Wet 2018 Wet
2018 Contr ol
P Valu es
Phenol, mg/l <0.001±0 <0.001±0 <0.01±0 0
0.00 0 Chloride,
mg/l
7331.57±362 4.4
5879.2±2958.
49
3478.58±4112.
06 28.72 0.05
Sulphate, mg/l
372.87±102.2
3 284.9±132.93 34.94±11.46 20.3
0.00 6
Nitrite, mg/l 0.02±0.01 0.02
0.31 7 Bicarbonate
mg/l 524.6±31.5 390.4 0.24
Sodium, mg/l 5929±2702.4 3143
0.35 5 Potassium,
mg/l 321.57±134.16
171.3 6
0.35 5 Calcium,
mg/l 90.95±20.74
76.10 5
0.35 5 Magnesium(
mg/l) 822.49±497.79
321.3 65
0.06 4 Cadmium,
(mg/l) <0.01a±0 0.003c±0 <0.001c±0 <0.005b±0 0b
0.00 0
Zinc, (mg/l) <0.01d±0 0.23b±0.07 0.06c±0.025 0.60a±0.03 0.56a 0.00 0
Iron (mg/l) 0.02±0 0.009±0.004 1.43±1.52 0.571
0.00 0 Copper
(mg/l) <0.01b±0 0.0075c±0 0.005c±0 0.029a±0.01 0.03a 0.00 0 Chromium
(mg/l) <0.01a±0 0.006b±0 <0.001b±0 <0.001b±0 0b
0.00 0 Nickel,
(mg/l) <0.01a±0 <0.001c±0 <0.001c±0 <0.002b±0
0.002 0b
0.00 0
EIA REVALIDATION FOR FORCADOS-YOKRI INTEGRATED PROJECT (NAG WELLS)
Parameters
Baseline
2001 2012 Dry 2012 Wet 2018 Wet
2018 Contr ol
P Valu es
Lead (mg/l) <0.01a±0 <0.001c±0 0.002±0 <0.002b±0 0b
0.00 0 Vanadium
(mg/l) <0.01a±0 <0.001b±0 <0.001b±0 <0.001b±0 0b
0.00 0 Arsenic
(mg/l) <0.001±0 <0.001±0 <0.001±0 0 1
Mercury,
(mg/l) <0.001±0 0 1
Barium
(mg/l) <0.01a±0 <0.001b±0 <0.001b±0 <0.001b±0 0b
0.00 0 Manganese
(mg/l) 0.01±0.01 0.002±0.001 <0.001±0 0 0.35
Silver, (mg/l) <0.002±0 0 1
Cobalt (mg/l) 0.129±0.147 0.246 0.81
Total Petroleum Hydrocarbon
(TPH) <0.01b <0.001c±0 <0.001c±0 0.11b±0.15
0.361 a
0.00 0 Total
Hydrocarbon
Content, mg/l 0.19±0.07 0.45
0.06 4
Oil and
grease, mg/l <0.001±0 <0.001±0 0.19±0.07 0.266 0.00 0
BTEX, mg/l <0.001±0 0 1
PAH, mg/l <0.001±0 <0.001±0 <0.001±0 0 1
Aliphatic Hydrocarbon
, mg/l 0.124±0.16 0.31
0.32 5 Microbiology
: 0
EIA REVALIDATION FOR FORCADOS-YOKRI INTEGRATED PROJECT (NAG WELLS)
Parameters
Baseline
2001 2012 Dry 2012 Wet 2018 Wet
2018 Contr ol
P Valu es
HUB, x
102cfu/ml 3.51±0.49 3.05±0.32 0
0.00 2
THB, x
102cfu/ml 0.6±0.11 0.52±0.11 1.34±0.45 1
0.00 2
HUF, x
102cfu/ml 0.07±0.04 0.13±0.08 0
0.00 2 Total Fungi x
102cfu/ml 2.41±0.57 1.77±0.24 1.02±0.02 0
0.00 0 Total
Coliform,
MPN/100ml 36.4±6.85 16.6±4.99 22.5±6.86 28.5
0.00 1 Faecal
Coliform Count,
MPN/100ml 14
0.15 7 A,b,c = significant
differences.
Same letters = no significant difference
Increasing Trend
Decreasing Trend
Hydrogen ion concentration: The pH trend (Figure 4.8) showed an initial decrease till 2012 followed by an increasing trend to 2018. The increase in pH in 2018 may be associated with tidal conditions during sampling regime. Flood tidal conditions usually show higher pH than ebb tidal conditions due to the influence of sea water.
EIA REVALIDATION FOR FORCADOS-YOKRI INTEGRATED PROJECT (NAG WELLS)
Figure 4.8: Trending of surface w ater pH in t he FYIP N AG field
Electrical conductivity: Electrical conductivity showed a consistent increasing trend from baseline in 2001 to present EIA in 2018. The increase in 2018 may be attributed to tide-related sea water influence particularly noting that the conductivity at the project area was significantly higher than that of the control (Figure 4.9). One of the controls is very close the shore where riverine dilution is high compared to the proposed project area. Local saline intrusion from effluents associated with various maritime activities in the area may also contribute to the observed trend.
Figure 4.9: Trending of surface w ater conduct ivity in t he FYIP N AG field Dissolved Oxygen: Figure 4.10 shows the trending of surface water DO levels in the FYIP NAG field. Dissolved oxygen showed a significant decreasing trend with highest values during the baseline in 2001 and lowest values during the present EIA in 2018. The decrease in DO concentration in 2018 at the proposed project location was similar to the situation at the control so
7 7.1 7.2 7.3 7.4 7.5 7.6 7.7 7.8 7.9 8
Baseline 2001
2012 Dry 2012 Wet 2018 Wet 2018 Control
pH
Surface water sampling year/season
y = 2423.9x + 9069.9 R² = 0.3722
0 5000 10000 15000 20000 25000 30000
Baseline 2001 2012 Dry 2012 Wet 2018 Wet 2018 Control
Electrical conductivity (uS/cm)
Surface water sampling year/season
EIA REVALIDATION FOR FORCADOS-YOKRI INTEGRATED PROJECT (NAG WELLS)
it cannot be attributed to activities around the project location. It reflects a general deterioration in water quality possibly associated with chronic organic inputs from riverine discharges and surface run-off.
Figure 4.10: Trending of surface w ater DO in t he FYIP N AG field
BOD: BOD showed an increasing trend (Figure 4.11) beginning from 2012 with highest levels during the present EIA. The increase in BOD during the present EIA at the proposed project location was also similar to that of the control indicating a general deterioration in organic pollution in the study area which may be attributed to chronic discharges of organic effluents and waste from rivers and surface run-off.
y = -0.919x + 10.089 R² = 0.6069
4 5 6 7 8 9 10
Baseline 2001 2012 Dry 2012 Wet 2018 Wet 2018 Control
DO (mg/l)
Surface water sampling year/season
EIA REVALIDATION FOR FORCADOS-YOKRI INTEGRATED PROJECT (NAG WELLS)
Figure 4.11: Trending of surface w ater BOD in t he FYIP N AG field
Nutrients: Phosphate showed a consistent decreasing trend from highest values in 2012 to lowest values in 2018 (Figure 4.12). However, when considering only the rainy season, there is no difference between 2012 and present EIA indicating that the lower value in 2018 is associated with the rainy season dilution of concentrations. The situation may also arise in connection with its assimilation during microbial degradation of organic matter since the trend was similar to that of dissolved oxygen. Lowest levels were observed at the control during the present EIA indicating that the activities at the proposed project locations are not responsible for the trend.
y = 0.8078x + 1.4548 R² = 0.287
0 1 2 3 4 5 6 7
Baseline 2001 2012 Dry 2012 Wet 2018 Wet 2018 Control
BOD(mg/l)
Surface water sampling year/season
y = -0.215x + 1.017 R² = 0.4198
-0.2 0 0.2 0.4 0.6 0.8 1 1.2 1.4
Baseline 2001 2012 Dry 2012 Wet 2018 Wet 2018 Control
Phosphate (mg/l)
Surface water sampling year/season
EIA REVALIDATION FOR FORCADOS-YOKRI INTEGRATED PROJECT (NAG WELLS)
Figure 4.12: Trending of surface w ater phosphat e in t he FYIP N AG field
Heavy metals: Figure 4.13 shows the trending for surface water Zinc, iron, and copper concentrations. Although copper was at trace levels, all three metals displayed an increasing trend with highest levels obtained during the present EIA. For zinc and iron, the levels in the proposed project area were higher than those of the control indicating a possible dilution effect from riverine discharge at the control or local contamination around the proposed project area.
Figure 4.13: Trending of surface w ater zinc and iron in t he FYIP N AG f ield
Organics: Petroleum hydrocarbons were not detected in surface water during the previous studies.
Their presence during the present EIA studies points to a deterioration in water quality with respect to hydrocarbons which may be attributed to increase land-and marine based pollution. Oil pollution in the Niger Delta has increased markedly due to illegal bunkering and refining of crude.
Microbiology: Figure 4.14 shows the trending for surface water total heterotrophic bacteria counts.
The bacterial counts showed consistent increasing trend with highest counts in 2018 during the present EIA. The relatively lower counts at the control compared to the proposed project area during the EIA is an indication of greater microbial activity around the proposed project area possible associated with elevated organic matter levels.
Total coliforms (Figure 4.15) did not show any apparent trend. Values decreased form 2001 to lowest in 2012 followed by an increase to a second peak in 2018 during the present EIA. The
y = 0.149x - 0.157 R² = 0.7171 y = 0.3074x - 0.5684
R² = 0.3523
-0.5 0 0.5 1 1.5 2
Baseline 2001 2012 Dry 2012 Wet 2018 Wet 2018 Control
Concentration (mg/l)
Surface water sampling year/season
Zinc, (mg/l) Iron (mg/l) Copper (mg/l)
Linear (Zinc, (mg/l)) Linear (Iron (mg/l))
EIA REVALIDATION FOR FORCADOS-YOKRI INTEGRATED PROJECT (NAG WELLS)
relatively higher values obtained at the control compared to the project location may be attributed to the proximity of one of one of the controls to the shore with potentially higher influence of land-based pollution including coliform bacteria.
Figure 4.14: Trending of surface w ater THB in t he FYIP N AG field
Figure 4.15: Trending of surface w at er total coliform in t he FYIP N AG field y = 0.202x + 0.36
R² = 0.4711
0 0.2 0.4 0.6 0.8 1 1.2 1.4 1.6
2012 Dry 2012 Wet 2018 Wet 2018 Control
THB (x102cfu/ml)
Surface water sampling year/season
0 5 10 15 20 25 30 35 40
2012 Dry 2012 Wet 2018 Wet 2018 Control
Total coliform (MPN/100 ml)
Surface water sampling year/season
EIA REVALIDATION FOR FORCADOS-YOKRI INTEGRATED PROJECT (NAG WELLS)