As, Hg in the Niger-Delta
As- und Hg-groundwater contamination by wastewater from oil and gas production in the Niger Delta region
Focus
Nigeria’s oil and gas industry has played a vital role in sustaining the country’s economy over the years. Despite its significant contribution to the economy, crude oil exploration and exploitation have left adverse environmental consequences resulting from large-scale and small-scale oil spills, and other industry-related activities (e.g., discharge of refinery production wastewater) in the eastern Niger Delta. As a result, toxic pollutants are released into the groundwater. Similarly, other ongoing anthropogenic activities (e.g., indiscriminate discharge of municipal/domestic sewage, and the presence of pit latrine toilets) have left the shallow groundwater vulnerable to pollution. For the affected communities, the groundwater serves as their only source of drinking, cooking, bathing, and washing water. Hence, groundwater protection remains vital for the entire population in the area. Of particular interest for my research are: (1) concentration, source, speciation, and transport and fate of mercury (Hg) in the wastewater-influenced groundwaters and sediments around the wastewater discharge outlet of the Port Harcourt Refining Company, (2) groundwater nitrate and nitrite contamination, source, transport, fate, and export potential to the nearby surface waters, and (3) concentration and distribution of benzene, source, and natural attenuation potentials under aerobic conditions in the groundwater resources of the eastern Niger Delta region of Nigeria. This research is the first attempt at the study location.
Fieldwork
My research samples were collected in the Eleme Local Government Area (Alesa, Ogale, Ebubu, and Alode), and the Okrika Local Government (Okochiri) of Rivers State in the eastern Niger Delta region of Nigeria. The sample site was characterized by the presence of:
- Wastewater discharge outlet stretching for over 1 km from the Port Harcourt Refining Company (a subsidiary of the Nigerian National Petroleum Corporation Limited) to Okrika Creek.
- The Nigerian National Petroleum Corporation Limited (NNPCL) underground petroleum pipelines, which run from the refinery to Umu Nwa (through Alode and Ogale), and Indorama Eleme Petrochemicals Plant (through Alode and Aleto).
- The Shell Petroleum Development Corporation owned-underground pipeline.
- Pipelines and Products Marketing Company12-joint surface pipeline that runs from the refinery to the Nigerian Port Authority (Rivers Port Complex).
- Indiscriminately disposed municipal and domestic sewage.
The research samples (i.e., groundwater and sediment) were collected in April 2021, April 2022, and May 2023. The groundwater samples were collected either (1) manually, using a laboratory-constructed water bail made of polyvinyl chloride material, or (2) with an electric submersible pump, already installed in the wells. The sediment samples were collected using a hand auger.
Funding of the project:
My research has been funded in part since January 2021 by grants from the German Research Foundation (DFG) to my supervisor, Prof. Dr. Thomas Pichler, University of Bremen, FB5, and the Petroleum Technology Development Fund (PTDF) grant, Nigeria.