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

subsoil (15.00 - 35.00 x 10 3 cfu/g), as would be expected from the higher levels
of contact with air and organic material in the topsoil. Hydrocarbon utilising
bacteria and fungi were not detected during either season.
Orior-Osemwende Community
Please note sampling in the Orior-Osemwende community was undertaken
during the wet season only.
Heavy Metal Composition. Iron had the highest heavy metal concentration
from the soil sampled in the Orior-Osemwende community (5,500.0 – 9,000.0
mg/kg), followed by chromium which demonstrated a narrow range of
concentration (13.500 – 14.000 mg/kg). Iron concentrations were higher in the
topsoil (9,000.0 mg/kg) than the subsoil (5,500.0 mg/kg) while chromium
concentrations were slightly elevated in the subsoil (14.000 mg/kg) compared
with the topsoil (13.500 mg/kg).
Anion and Cation Analysis. Nitrate had the highest anionic concentration
levels (4,500.0 – 5,300.0 mg/kg) followed by phosphate (72.000 – 101.00
mg/kg). As found to be the case at the other sampling locations, the nitrate
concentrations were found to be higher in the topsoil (5,300.0 mg/kg) than the
subsoil (4,500.0 mg/kg). Sulphate was not detected within the soil. Among the
cations sampled, potassium recorded the highest (1,950.0 – 2,405.0 mg/kg),
and sodium the lowest concentrations (14.000 – 35.500 mg/kg). The potassium
concentrations were higher in the subsoil compared with the topsoil (2,405.0
and 1,950.0 mg/kg respectively), while sodium concentrations were higher in
the topsoil than the subsoil (35.500 and 14.000 mg/kg respectively).
Hydrocarbon Content. Oil and grease were not detected in the soil. THC was
detected between 0.268 – 0.339 mg/kg in the top and subsoil respectively
indicating low levels of hydrocarbon pollution.
Physico-chemical properties. The soil composition was predominantly sand
with the soil on average having the following composition: sand (96.980), silt
(1.5200) and clay (1.5100). The percent composition of the respective
components in the topsoil were recorded at 97.000, 2.1500 and 0.85000. In the
subsoil the percentage compositions were recorded at 96.950, 0.88000 and
2.1700.
Microbial Analysis. The total heterotrophic bacteria count ranged between
50.00 x 10 3 and 290.0 x 10 3 cfu/g. The total heterotrophic fungi ranged between
11.00 x 10 3 and 58.00 x 10 3 cfu/g. In both instances the total heterotrophic
bacteria and heterotrophic count were found to be higher in the topsoil (290.0
and 58.00 x 10 3 cfu/g) compared to those observed in the subsoil (50.00 and
11.00 x 10 3 cfu/g). Hydrocarbon utilising bacteria and fungi were not detected
during either season.
AZURA EDO IPP
4-14
DRAFT EIA REPORT