Hydro-geochemical characterization and groundwater modelling of the subsurface around Ughelli West Engineered Dumpsite in the Western Niger Delta, Nigeria

Aweto, K. E.; Ohwohere-Asuma, O.; Ovwamuedo, G.; Atiti, P. C.

doi:10.4314/njtd.v20i2.1393

Cited by 4 publications

(1 citation statement)

References 13 publications

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“…In this study, changes in Eh and pH have been identi ed as an important controlling factor for the dominance of a particular aqueous species of nitrogen predicted to be present at 25°C with an activity value of 1 x 10 -3 M dissolved nitrogen in the groundwater. The 1 x 10 -3 M used is the NO 3 − activity value commonly found in NO 3 − polluted groundwaters (Appelo &Postma 2005). It is, however, essential to note that changes in pressure do not necessarily introduce substantial errors in the Eh-pH boundaries calculated for 1 bar.…”

Section: Biogeochemical Processes Of Redox Reaction On Nitrogen (N) B...mentioning

confidence: 99%

Source, transport and fate of nitrate in shallow groundwater in the eastern Niger Delta

Aleku,

Dähnke,

Pichler

2024

Preprint

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The eastern Niger Delta region in Nigeria is a hotspot for reactive nitrogen pollution due to extensive animal husbandry, pit latrine usage and agricultural practices. Despite the high level of human activity, the sources and processes affecting nitrogen in groundwater remain understudied. Groundwater nitrate (NO3−) concentrations are highly variable, with some areas recording values well above the safe drinking water threshold of 50 mg/L. This is particularly true near municipal sewage systems. Elevated nitrite (NO2−) and ammonium (NH4+) concentrations were also detected in the study area. Sewage analysis revealed NO3− concentrations ranging from 1 to 145 mg/L, NO2− from 0.2 to 2 mg/L, and notably high NH4+ concentrations. A comparison of major ions indicated that 71%, 90%, 87%, and 92% of groundwater samples surpassed reference site levels for calcium (Ca2+), sodium (Na+), potassium (K+), and chloride (Cl−), respectively, pointing to sewage as a likely source of contamination. The NO3−/Cl− ratios at several sites suggested that most groundwater NO3− originates from human waste. Stable isotope analysis of NO3− showed a general enrichment in 15N and, in some cases, a depletion in 18O, indicating that the NO3− originates from sewage-derived NH4+ nitrification. Although denitrification, a process that reduces NO3−, is present, the high dissolved oxygen (DO) and NO3− levels in the groundwater suggest that denitrification is insufficient to fully mitigate NO3− pollution. Consequently, there is a risk of NO3− leaching from shallow aquifers into the Niger Delta’s surface waters and ultimately into the coastal ocean.

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Section: Biogeochemical Processes Of Redox Reaction On Nitrogen (N) B...mentioning

confidence: 99%

Source, transport and fate of nitrate in shallow groundwater in the eastern Niger Delta

Aleku,

Dähnke,

Pichler

2024

Preprint

View full text Add to dashboard Cite

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Source, transport, and fate of nitrate in shallow groundwater in the eastern Niger Delta

Aleku,

Dähnke,

Pichler

2024

Environ Sci Pollut Res

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The eastern Niger Delta region in Nigeria is a hotspot for reactive nitrogen pollution due to extensive animal husbandry, pit latrine usage, and agricultural practices. Despite the high level of human activity, the sources and processes affecting nitrogen in groundwater remain understudied. Groundwater nitrate (NO3−) concentrations are highly variable, with some areas recording values well above the safe drinking water threshold of 50 mg/L. This is particularly true near municipal sewage systems. Elevated nitrite (NO2−) and ammonium (NH4+) concentrations were also detected in the study area. Sewage analysis revealed NO3− concentrations ranging from 1 to 145 mg/L, NO2− from 0.2 to 2 mg/L, and notably high NH4+ concentrations. A comparison of major ions indicated that 71%, 90%, 87%, and 92% of groundwater samples surpassed reference site levels for calcium (Ca2+), sodium (Na+), potassium (K+), and chloride (Cl−), respectively, pointing to sewage as a likely source of contamination. The NO3−/Cl− ratios at several sites suggested that most groundwater NO3− originates from human waste. Stable isotope analysis of NO3− showed a general enrichment in 15N and, in some cases, a depletion in 18O, indicating that the NO3− originates from sewage-derived NH4+ nitrification. Although denitrification, a process that reduces NO3−, is present, the high dissolved oxygen (DO) and NO3− levels in the groundwater suggest that denitrification is insufficient to fully mitigate NO3− pollution. Consequently, there is a risk of NO3− leaching from shallow aquifers into the Niger Delta’s surface waters and ultimately into the coastal ocean.

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Pipeline-Related Residential Benzene Exposure and Groundwater Natural Attenuation Capacity in the Eastern Niger Delta, Nigeria

Aleku,

Biester,

Pichler

2024

Environments

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This study was conducted to investigate the presence of benzene in the ground and drinking water in the eastern Niger Delta, where multiple oil and gas production facilities are present. Samples from drinking water wells were collected for measurements of benzene, toluene, ethylbenzene, and xylenes (BTEX). Additionally, the dissolved organic carbon (DOC) concentration was determined for the first time to establish the groundwater’s total hydrocarbon and non-hydrocarbon load. The groundwater BTEX and benzene levels were up to 3904 µg/L and 3500 µg/L, respectively. DOC concentrations were up to 49 mg/L. The highest benzene concentrations were detected in wells near an underground petroleum pipeline. However, the concentrations decreased with distance from the pipeline to levels less than 0.1 µg/L. Despite benzene contamination, the aquifer has shown promising aerobic attenuation potential, having up to a 7.5 (95%) mg/L DO level and 2.11 mg/L BTEX biodegradation capacity for DO. However, the high groundwater temperature of up to 32.5 °C may weaken attenuation. The benzene and BTEX point attenuation rates ranged from 0.128 to 0.693 day−1 and 0.086 to 0.556 day−1, respectively. Hence, by natural attenuation alone, up to 66.5 and 85 years would be required to reach Nigeria’s groundwater benzene and BTEX remediation goals, respectively.

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Hydro-geochemical characterization and groundwater modelling of the subsurface around Ughelli West Engineered Dumpsite in the Western Niger Delta, Nigeria

Cited by 4 publications

References 13 publications

Source, transport and fate of nitrate in shallow groundwater in the eastern Niger Delta

Source, transport and fate of nitrate in shallow groundwater in the eastern Niger Delta

Source, transport, and fate of nitrate in shallow groundwater in the eastern Niger Delta

Pipeline-Related Residential Benzene Exposure and Groundwater Natural Attenuation Capacity in the Eastern Niger Delta, Nigeria

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