Azura-Edo Independent Power Plant Environmental Impact ... - IFC

Transmission Line Corridor
Please note sampling in the transmission line corridor was undertaken during
the wet season only.
Heavy Metal Composition. Iron had the highest concentration from the soil
sampled along the transmission line corridor (14, 500 – 33, 000 mg/kg in the
top and subsoil respectively). The second highest heavy metal concentration
was chromium which illustrated the same levels as those observed in the
Orior-Osemwende community.
Anion and Cation Analysis. Nitrate had the highest anionic concentration
levels (3,350.0 – 7,750.0 mg/kg in the sub and topsoil respectively) followed by
phosphate (50.000 - 91.500 mg/kg in the sub and topsoil respectively).
Sulphate was not detected within the soil. Among the cations sampled,
potassium recorded the highest concentration (350.00 – 1,650.0 mg/kg in the
sub and topsoil respectively), with sodium again showing the lowest
concentration in the soil (46.000 – 62.000 mg/kg in the top and subsoil
respectively).
Hydrocarbon Content. Oil and grease was not detected in the soil. The THC
concentration ranged between 0.4430 and 0.6020 mg/kg along the
transmission line corridor. The THC concentration was higher in the topsoil,
as illustrated in the concentration levels listed above.
Physico-chemical properties. The soil composition was predominantly sand
with the soil having on average the following percentage composition: sand
(96.500), silt (2.0900) and clay (1.4200). Sand and silt were found to be at
higher concentrations in the topsoil (96.880 and 2.6800 percent). The clay
composition was higher in the subsoil (0.44000).
Microbial Analysis. The total heterotrophic bacteria count ranged between
80.00 x 10 3 and 375.0 x 10 3 cfu/g. The total heterotrophic fungi ranged
between 2.000 x 10 3 and 106.0 x 10 3 cfu/g. The total heterotrophic bacteria and
fungi count were found to be higher in the topsoil (375.0 and 106.0 x 10 3 cfu/g)
compared to the levels observed in the subsoil (80.00 and 2.000 x 10 3 cfu/g).
Hydrocarbon utilising bacteria and fungi were not detected during the wet
season.
Overview
The soil sampling was conducted across the Project site and included
southern, northern and western portions as well as sampling at the
communities of Ihovbor-Evboeka and Orior-Osemwende and within the
proposed transmission line corridor. The physico-chemical properties across
the different portions of the Project site were similar, with soils on average
demonstrating a pH range between 5.00 and 6.00, with the soil mainly being
composed of sandy loam. The microbial content of the soil also illustrated
similar patterns across the different portions of the Project site, with slightly
AZURA EDO IPP
4-15
DRAFT EIA REPORT