Socio-economic baseline for oil-impacted communities in Ogoniland: towards a restoration framework in Niger Delta, Nigeria.

This study documents the socio-economic baselines in selected oil-impacted communities prior to the commencement of the Ogoni clean-up and restoration project. Adopting mixed approach consisting of semi-structured interviews, focus group discussions (FGDs), key informant interviews (KIIs), and household surveys, we surveyed the pre-remediation socio-economic conditions in the Ogoniland communities between July 2018 and March 2019. Results indicated that almost all respondents (99.6%) agreed that the smell of petroleum products or crude oil was evident in the air they breathed even as there were visible black particles (soot) in the respondents' nostrils, on their clothes, and in water. The respondents described the ambient air as smoky and choked with an offensive smell. The household waters were smelly, brownish, or oily, and most respondents (76%) cannot afford to treat their water. Forty-two percent of the respondents who relied on fishing and farming for a living sought for alternative means of subsistence and acknowledged that oil pollution caused stunted growth and low crop yield. The majority of respondents (91%) reported falling fish catches, while the fish caught smell and taste of oil, lowering their market value and posing a potential health risk to consumers. It is evident that oil pollution has impacted the socio-ecological values and sustainable livelihood in Ogoniland. This study provides baseline data for monitoring post-remediation socio-economic improvements in Ogoniland. It also highlights areas of urgent intervention to improve livelihood, and access to basic amenities (e.g., potable drinking water), waste management infrastructure, and statutory policy changes for sustainable development in Ogoniland.

Prospects of emerging PAH sources and remediation technologies: insights from Africa.

Remediation of polluted environmental media is critical to realization of the goals of the United Nations Decade on Ecosystem Restoration (UNDER) project. Many natural-resource dependent economies in Africa are characterized by numerous contaminated sites resulting from conventional and artisanal natural-resource mining. Alongside these extractive activities, there are refining, processing, and power plant operations, agriculture, urban, and infrastructure developments that contribute to increased discharges of toxins into the environment, particularly polycyclic aromatic hydrocarbons (PAHs), which are carcinogenic in nature. As a result, human and environmental receptors (i.e., air, water, soil, and biota) face increasing risk of exposure to higher concentrations of PAH. Evidence exists of widespread PAH contamination and in some instances where corrective action has been taken, residual contaminant levels exceeding regulatory thresholds remain in the environment due to the use of inappropriate and unsustainable remedial methods. Considering the long-term harmful effects of PAH on human and ecosystem health, land use, and the complexity of Africa's environmental deterioration, it is essential to explore remediation strategies that benefit both the environment and the economy. This review examined the status, opportunities, and challenges related to the application of emerging green technologies to remediate PAH-contaminated sites in five African countries (South Africa, Nigeria, Angola, Egypt, and Kenya). This paper concludes that bioremediation presents a sustainable option, considering its low net emissions and environmental footprints, and its low economic cost to Africa's poor communities and overburdened economy. However, an integration of biological and physico-chemical approaches could address various compounds and concentrations of PAH contamination.

Analysis of polycyclic aromatic hydrocarbons (PAHs) in surface sediments and edible aquatic species in an oil-contaminated mangrove ecosystem in Bodo, Niger Delta, Nigeria: Bioaccumulation and human health risk assessment.

This work investigated the occurrence and risks associated with polycyclic aromatic hydrocarbons (PAHs) in tissues from five commonly consumed aquatic species (swimming crabs, estuarine shrimp, tiger prawns, periwinkles, and tilapia) and sediment across six sites in the area around Bodo town, in the Niger Delta region of Nigeria. We aimed to establish a relationship between PAH concentrations in sediment and biota, and to derive biota-sediment accumulation factors (BSAFs). Risks to human health associated with consumption of impacted food sources were assessed based on measured biotic concentrations of PAHs. The average concentration of PAHs and the number of PAHs measured above the limit of quantification varied greatly between different biota, with the lowest average concentrations observed in tilapia, followed by tiger prawns, crabs, estuarine shrimp, and the highest concentrations were observed in periwinkles. Similar to biotic concentrations, BSAFs were found to vary greatly across species, sites, and PAHs, though BSAFs for all organisms except periwinkles were below a value of 1. In periwinkles, BSAFs exceeded a value of 1 for phenanthrene (BSAF = 1.7), pyrene (1.5) and benzo[k]fluoranthene (1.7). Risks to human health associated with consumption of these species were assessed using the BaP toxic-equivalent approach for cancer risks and the toxic unit approach which jointly considered carcinogenic but also non-cancer hazards. The BaP toxic-equivalent approach showed that the excess lifetime cancer risk resulting from daily consumption of 0.2 kg of seafood ranged between 1.3 × 10-6 for tiger prawn and tilapia to 4.1 × 10-6 for periwinkles, which is below the excess lifetime cancer risk of 10-4 used by Dutch and Nigerian authorities for sediment intervention values. This finding is supported by the results obtained from the toxic unit approach which indicates that the ratios of the estimated dose and the maximal permissible risk level for summed PAHs never exceeded 1.

Recovery of infauna macrobenthic invertebrates in oil-polluted tropical soft-bottom tidal flats: 7 years post spill.

Coastal oil spills constitute significant threat to biotic energy distribution, and biodiversity integrity amongst others. This study monitored the recovery of low-intertidal, soft-bottom infauna macrobenthic invertebrates in Bodo Creek intermittently over a 7-year period post oil spill. Samples were taken twice a month (spring and neap low tides) for 6 months (September 2015-February 2016) at sites previously studied (pre-spill baseline studies, 3-year and 5-year post-spill studies) for the effects of oil pollution using the same sampling methods used during initial studies of the same area. Comparatively, the initial studies reported Polychaeta as the dominant class against the dominant Crustacea reported in this 7-year post-spill study, indicating a change in the community structure of the study area. Infauna macro-invertebrate communities recorded showed an improvement (that is, increased species richness and number of individuals) over the initial 3-year and 5-year post-spill studies. However, relating the results to the initial baseline pre-spill studies, an annual average of 9.7% recovery rate was observed. Analysis of results showed that the total hydrocarbon content (THC) of the sediment remained high (90.08-12,184 mg/kg) but was markedly lower than levels observed during the initial post-spill study (6422-7186 mg/kg). Tidal flushing and biodegradation processes were deemed responsible for the reduction in THC. This study provides a rare dataset that describes the effects of oil pollution on a previously near-pristine estuarine environment in the tropics.

Status, progress and challenges of phytoremediation - An African scenario.

Environmental pollution occasioned by artisanal activities and technical failures at exploration sites has affected mostly oil producing and other mineral resources mining regions in developed and developing nations. As conventional techniques of remediation seem to be progressively unreliable and inefficient, contaminated land management experts have adopted a plant-based technology described as 'phytoremediation' for effective detoxification and removal of contaminants in substrate environmental media (soil and sediment). This technique, has gained public acceptance because of its aesthetic, eco-friendly, solar energy driven and low cost attributes. With complexity of environmental pollution in Africa, identification of appropriate remediation approach that deliver net environmental benefit and economic profit to the society is vital, while also focusing on the exploitation of plants genetic tools for more clarity on phyto tolerance, uptake and translocation of pollutants. In this article, we reviewed the status, progress and challenges of phytoremediation in selected African countries (South Africa, Nigeria, Tanzania, Zambia, Egypt and Ghana), the ecological impact of the pollutants, phytoremediation strategies and the possible plants of choice. Besides highlighting the support roles played by soil fauna and flora, the fate of harvested biomass/dieback and its future prospects are also discussed. We further explored the factors challenging phytoremediation progress in Africa, amidst its promising potentials and applicability for sustainable ecosystem management paradigm.

Remediation of contaminated lands in the Niger Delta, Nigeria: Prospects and challenges.

Contamination of the total environment (air, soil, water and biota) by crude oil has become a paramount interest in the Niger Delta region of Nigeria. Studies have revealed variable impacts of oil toxicity on the environment and exposed populations. The revelation gained much international attention in 2011 with the release of Environmental Assessment of Ogoniland report by the United Nations Environment Programme (UNEP). This has up scaled local and international pressures for urgent clean-up and restoration of degraded bio-resource rich environments of the Niger Delta, starting from Ogoniland. Previous remediation attempts in the area had failed due to erroneous operational conclusions (such as conclusions by oil industry operators that the Niger Delta soil is covered by a layer of clay and as such oil percolation remains within the top soil and makes remediation by enhanced natural attenuation (RENA) suitable for the region) and the adoption of incompatible and ineffective approaches (i.e. RENA) for the complex and dynamic environments. Perennial conflicts, poor regulatory oversights and incoherent standards are also challenges. Following UNEP recommendations, the Federal Government of Nigeria recently commissioned the clean-up and remediation of Ogoniland project; it would be novel and trend setting. While UNEP outlined some measures of contaminated land remediation, no specific approach was identified to be most effective for the Niger Delta region. Resolving the technical dilemma and identified social impediments is the key success driver of the above project. In this paper, we reviewed the socio-economic and ecological impacts of contaminated land in the Niger Delta region and the global state-of-the-art remediation approaches. We use coastal environment clean-up case studies to demonstrate the effectiveness of bioremediation (sometimes in combination with other technologies) for remediating most of the polluted sites in the Niger Delta. Bioremediation should primarily be the preferred option considering its low greenhouse gas and environmental footprints, and low-cost burden on the weak and overstretched economy of Nigeria.

Conflicts - Oil Exploration and Water.

Water resources and water quality are closely related to oil exploration, refining and distribution. Since oil products provide over 90% of transport energy in almost all countries it is apparent that any oil operation is an inherent risk for water resources. Since water supplies will be increasingly stressed as a consequence of climate change and population increase the environmental risks associated with oil exploration may intensify. Thus, there are more reasons than CO2 emissions and climate change to cut down on oil production and consumption. In this paper water related risks are discussed from two aspects: (1) water use and water pollution as a result of normal exploration, refining and distribution, (2) water and marine life contamination caused by accidents. It will be exemplified by some major oil accidents, too often caused by human errors or negligence. Ecological effects of oil contamination for seawaters and freshwaters are discussed. Some aspects of social and economic consequences are examined. Some possibilities for mitigating oil leakage risks are highlighted.

Community responses of intertidal soft-bottom macrozoobenthos to oil pollution in a tropical mangrove ecosystem, Niger Delta, Nigeria.

Preliminary impact assessment of two large oil spill incidents at Bodo Creek, in the Niger Delta, was undertaken, focusing on intertidal macrozoobenthos. Post-spill number of species and abundance were measured against recent pre-spill baseline data from the same study area. Results show that surface and infauna communities suffered severe reduction in abundance and number of species reduced by 81% after the spills, with two of the resampled sites having no taxa at all. Capitella capitata populations increased several-fold over pre-spill numbers. The impact of the oil spills is discussed in relation to local livelihoods and ecosystem integrity. The Niger Delta endemic lucinid, Keletistes rhizoecus, is proposed as a potential bioindicator for monitoring hydrocarbon contamination in Niger Delta estuaries.