CHAPTER ONE
1.1 INTRODUCTION
GENERAL
This report involves soil and surface water contamination appraisal of five potentially impacted areas located in Khana Local Government Area, Rivers State, Nigeria.
The area form part of the sites covered by United Nations Environment Programme (UNEP) in 2011 and includes Duburu. Detailed descriptions and locations of these sites are given in chapter 2.
1.2 OBJECTIVE
The present assessment is required to achieve the following objectives;
- To delineate the lateral and vertical extent of oil spill on soil and surface water systems.
- To confirm the concentration of total petroleum hydrocarbon (TPH), polyaromatic hydrocarbon (PAH) and volatile Compounds (BTEX)
- Evaluate results obtained in line with DPR regulatory standards (target and intervention values) for contaminated surface water and soil.
- Use data obtained to determine if remedial measures are required for any identified affected surface soil.
1.3 SCOPE OF WORK
The work scope for the study includes the following:
- Ø Contamination appraisal which generally involves surface and near-surface assessment of soil.
- Ø The soil survey involves an intrusive aspect using auger drilling in which subsurface soil materials were assessed.
- Ø Laboratory testing and an appraisal of the results all in accordance with international Standards and the Department of Petroleum Resources (DPR) Environmental Guidelines and Standards for the Petroleum Industry in Nigeria (EGASPIN).
1.4 ENVIRONMENTAL SETTING
SITE LOCATION, DESCRIPTION AND BACKGROUND INFORMATION
Detailed descriptions of each site together with the location, specific characteristics and main features are summarized in Table 1 below. A plan indicating the location of Khana L.G.A. the host local council of all the area is included as Figure 1. The oil spill in the objective areas occurred in January 1994 during which time the cause of the spill was unknown. As at the time of spill, environmental media affected by free phase oil were soils in farm lands and stagnant and running surface water. Visual observation indicated oil sheen and oil patches on surfaces of running and stagnant water pools and when bottom sediment is disturbed, stain on vegetation. Areal extent of the spill as at 1994, ranged from 2 – 5km long and 20 – 140m wide, and an area of between 50,000 – 140,000m2. Average depth of penetration of free phase oil was 0.03m, while the nearest habitation was <100m.
