The Impacts of Oil and Gas Production to Soil in Bentiu Unity State, South Sudan

The Impacts of Oil and Gas Production to Soil in Bentiu Unity State, South Sudan

Bul Duot Kuer., Zedekia J. Ongeri

Department of Environmental Studies, Kenyatta University, Nairobi, Kenya

DOI: https://dx.doi.org/10.47772/IJRISS.2025.906000110

Received: 23 May 2025; Accepted: 27 May 2025; Published: 02 July 2025

ABSTRACT

This study investigates the spatial and temporal distribution of soil contaminants in the Bentiu region of Unity State, South Sudan, with a focus on areas influenced by oil and gas production activities. Soil samples were collected from three main sites—Nahm River (upstream and downstream), Abuk River (near a local community) and a remote control site. Analytical assessments targeted concentrations of key heavy metals (lead, cadmium, chromium, mercury) and hydrocarbons. The results revealed elevated levels of pollutants at sites proximal to oil production infrastructure, notably in the Nahm and Abuk River locations. Hydrocarbon concentrations consistently exceeded accepted environmental thresholds across impacted sites, with lead and chromium frequently registering above baseline levels. However, one-way ANOVA tests indicated no statistically significant differences (p > 0.05) in pollutant concentrations among sites, a finding corroborated by post hoc Tukey HSD analyses. These results suggest a broadly dispersed pattern of contamination rather than sharply localized impacts, possibly due to cumulative and diffused industrial activities. The study highlights the urgent need for expanded and more granular environmental monitoring, including higher sampling frequency and additional ecological indicators, to more accurately characterize pollution dynamics and inform targeted remediation strategies.

Keyword: Oil and Gas production; Soil; Heavy Metals; Hydrocarbons; South Sudan

INTRODUCTION

The exploration and production of oil and gas have been pivotal in driving economic development globally [1]. However, these activities often come with significant environmental costs, particularly concerning soil contamination. Soil serves as a fundamental component of terrestrial ecosystems, providing essential functions such as nutrient cycling, water filtration, and habitat for numerous organisms. However, anthropogenic activities, particularly oil and gas extraction, have led to significant soil contamination, posing threats to environmental health and human well-being. The introduction of pollutants such as petroleum hydrocarbons and heavy metals into the soil can disrupt these vital functions, leading to long-term ecological and health consequences

Oil and gas production processes, including drilling, transportation, and refining, can release a variety of pollutants into the environment. These pollutants often find their way into the soil through spills, leaks, and improper waste disposal practices. Petroleum hydrocarbons, such as aliphatic and aromatic compounds, are commonly introduced into soils during extraction activities. These hydrocarbons can persist in the environment, leading to soil degradation and potential harm to plant and animal life.

Heavy metals, including lead (Pb), cadmium (Cd), chromium (Cr), and mercury (Hg), are also frequently associated with oil and gas production activities. These metals can enter the soil through various pathways, such as the deposition of industrial wastes or the leaching from contaminated materials. Once in the soil, heavy metals can accumulate over time, posing risks to soil fertility, plant health, and potentially entering the food chain [2].

Oil spills and deposition of oil and gas production products, have significant environmental implication to soil health and ecosystem stability [3]. When pollutants and heavy metals are released into the environment, they can infiltrate the soil, leading to a range of detrimental effects that persist over time. One of the primary impacts of oil contamination is the alteration of soil’s physical and chemical properties. This introduction leads to increased soil pH, which affects nutrient availability and microbial activity. For instance, studies have shown that oil and gas contamination can raise soil pH, disrupting nutrient cycling and reducing soil fertility [4]. Additionally, oil and gas can decrease the cation exchange capacity (CEC) of soils, impairing their ability to retain essential nutrients and water [5]. Further, these pollutants lead to Microbial and Biological Disruption, which play a crucial role in maintaining soil health by decomposing organic matter and facilitating nutrient cycling. Oil spills can disrupt these microbial communities, leading to reduced biodiversity and altered microbial functions. Research indicates that oil contamination can decrease microbial biomass and enzymatic activities, such as urease and dehydrogenase, which are vital for nutrient cycling. Furthermore, oil spills can create anaerobic conditions in the soil, further inhibiting microbial activity and leading to the accumulation of toxic metabolites [6]. Also, long term soil degradation can be experienced I areas experiencing oil spills. This prolonged contamination can hinder natural soil recovery processes and necessitate intervention for remediation. The degradation of soil quality due to oil spills has significant implications for agriculture and ecosystems. Contaminated soils can lead to reduced crop yields and compromised food security. Additionally, the loss of soil fertility and microbial diversity can impair ecosystem functions, affecting plant growth [7] and the overall health of the environment. Other impacts include food chain contamination [8], [9] surface and ground water pollution [10], [11] and Human Risk [12].

In South Sudan, the town of Bentiu, located in Unity State, has emerged as a focal point for such environmental concerns due to intensive oil extraction activities. The area hosts several oil fields operated by companies such as the Greater Pioneer Operating Company (GPOC) and the Sudd Petroleum Operating Company (SPOC). While these operations have contributed to economic gains, they have also been associated with environmental degradation. Reports from local communities and environmental groups suggest increasing soil degradation and pollution near oil fields and adjacent water bodies. The persistence of these pollutants in the soil necessitates effective monitoring and remediation strategies to mitigate their impact.

The environmental risks associated with oil production are often amplified in post-conflict or underdeveloped settings. South Sudan presents a perfect example. Decades of civil war and political instability have not only undermined governance structures but have also disrupted basic environmental oversight. In such contexts, multinational oil companies may operate in the absence of stringent regulatory frameworks, while local communities often lack the resources or political voice to advocate for environmental protection.

This governance vacuum frequently results in unmonitored discharges of pollutants, poor waste management practices, and delayed responses to environmental emergencies such as spills. Moreover, because many affected areas are rural and heavily dependent on natural resources for subsistence farming, the consequences of soil contamination extend beyond environmental degradation to encompass issues of food security, public health, and socio-economic development. Despite these stakes, environmental research in these regions remains limited, due in part to logistical challenges and security concerns.

However, in the region, where infrastructure and resources for environmental management are limited, addressing soil contamination remains a significant challenge. Despite anecdotal evidence, there is limited empirical data on the extent and distribution of soil contamination in the region. The paper hypothesizes that, oil and gas production activities in Bentiu, Unity State, have led to significant soil contamination with petroleum hydrocarbons and Heavy metals that has negative impacts on soil. Further the research pursues the question on what are concentration level of petroleum hydrocarbons and heavy metals and their impacts to soil. This study addresses this gap by conducting a systematic assessment of soil pollutants, focusing on heavy metals and hydrocarbons, which are common by-products of oil production

LITERATURE REVIEW

Oil spills have been widely documented as one of the most significant environmental challenges in oil-producing regions. When crude oil or petroleum products are released into the environment—whether through pipeline leaks, accidental spills, or illegal refining activities—they can cause severe and often long-lasting damage to soil ecosystems. Across globe, the extent of this damage varies, but common effects include reduced soil fertility, altered pH, disrupted microbial communities, and long-term degradation of agricultural potential.

Oil contamination in soil is a global environmental concern. According to Alloway [4], petroleum hydrocarbons and heavy metals are persistent pollutants that degrade soil quality and disrupt microbial ecosystems. Studies from Nigeria’s Niger Delta [13], [14] and Sudan [11] show that oil-producing regions often exhibit elevated levels of lead, cadmium, and hydrocarbons, with serious implications for agriculture and human health.

One of the most direct impacts of oil and gas production on soils is contamination by hydrocarbons and heavy metals. Spills and leaks during drilling, storage, and transport of petroleum products lead to the deposition of crude oil and refined petroleum compounds in the soil. These pollutants often contain polycyclic aromatic hydrocarbons (PAHs), which are persistent and toxic to soil organisms [15] For example, in Alberta, Canada, studies have shown significant soil contamination around oil sands operations, with elevated levels of arsenic, lead, vanadium, and PAHs [16]. In Assam, India, oil exploration and transportation have led to frequent contamination of agricultural soils with PAHs, resulting in reduced microbial diversity, lower soil enzyme activity, and poor crop yields [17]. Similarly, in the Niger Delta region of Nigeria, extensive oil spills from pipelines and illegal refining activities have led to the accumulation of high levels of PAHs in soils. These compounds persist in the environment for years, degrading soil health and posing long-term risks to food security and human health through bioaccumulation [18], [19].

Hydrocarbon contamination alters the chemical composition of soil and reduces its fertility. It leads to an increase in soil acidity or alkalinity and can inhibit microbial activity essential for nutrient cycling [20]. In the U.S., particularly in Texas and North Dakota, regions with intense shale oil extraction have reported soil degradation due to frequent leaks of brine and produced water, which contain high levels of sodium and other salts that cause soil salinization [21]. Similarly, in Nigeria’s Niger Delta, repeated oil spills have significantly increased soil acidity and decreased levels of essential nutrients like nitrogen and phosphorus, resulting in poor crop productivity and long-term soil infertility [14]. Moreover, microbial biomass and enzyme activity have been severely suppressed, compromising the natural soil restoration processes. Laliteshwari et al.,  [22], research found contaminated paddy fields have shown altered pH levels and reduced microbial respiration, further impairing the land’s agricultural potential.

Soil microbial communities play a crucial role in maintaining soil health and ecosystem functioning. Oil and gas activities can severely disrupt these microbial populations through the introduction of toxic substances and alteration of the soil environment. Research conducted in North Sea oil platforms has shown that soils near drilling sites experience reduced microbial biomass and a decline in microbial diversity [23]. In addition, bioremediation efforts in oil-affected soils often highlight the challenges of restoring microbial health. While bio-stimulation and bio-augmentation can enhance the breakdown of hydrocarbons, they rarely restore the original microbial composition [24]. In some areas of the U.S. and Canada, microbial imbalances have persisted decades after site abandonment or remediation.

Soils contaminated by oil and gas production are difficult to restore to their original state. Natural attenuation is a slow process, and active remediation efforts can be expensive and labor-intensive. In many areas, particularly where unconventional oil extraction such as hydraulic fracturing (fracking) occurs, soils may remain unsuitable for agriculture or habitation long after drilling ceases [25]. Pakistan’s Sindh province, conventional and exploratory shale oil activities have polluted soils with heavy metals and hydrocarbons, rendering them unfit for cultivation. Studies indicate that improper wastewater disposal and drilling mud accumulation lead to persistent changes in soil pH and organic matter content, with some areas becoming barren [9]. In India’s Cambay Basin, unconventional oil drilling has caused soil compaction and contamination, which in turn inhibits natural revegetation and long-term land recovery. In Western Europe, strict regulations and remediation policies have helped mitigate long-term impacts. For instance, Norway’s Petroleum Act mandates site restoration, including the removal of contaminated soils and revegetation [26]. However, in practice, restoration success varies widely depending on site conditions and pollutant concentrations.

The degradation of soil due to oil and gas activities also has broader socio-environmental implications. Reduced soil quality affects agricultural productivity and water quality, especially in rural and Indigenous communities that depend on land-based livelihoods [27]. In Canada, Indigenous groups near oil sands sites have reported concerns over declining soil and water quality, which in turn impact traditional food sources and cultural practices [28].

In South Sudan, literature remains sparse. However, United Nations Environment Programme [10] highlighted environmental degradation in oil zones, attributing contamination to poor waste management and insufficient regulatory oversight. According to Tsegaye et al., [29], the post-conflict nature of South Sudan complicates environmental governance, with weak institutions unable to enforce existing laws. Research by Magok [7] reported elevated hydrocarbon levels in surface waters near oil fields in Unity State, but comprehensive soil assessments remain rare. Also oil exploration in Unity State has led to saline wastewater leaks that elevate soil alkalinity, reduce moisture retention, and harm beneficial microbial populations essential for organic matter decomposition and nutrient cycling [30]. Oil operations in the Unity and Upper Nile States have resulted in long-lasting contamination from drilling fluids and saline produced water, with affected soils showing high salinity and residual hydrocarbons years after the cessation of operations [30]. These degraded lands have become largely unproductive for farming or grazing, displacing communities and reducing local food security.

MATERIALS AND METHOD

Study area

This study was conducted in Bentiu, located in Rubkona County of Unity State, in northern South Sudan, near the international boundary with the Republic of Sudan. The area lies approximately 654 kilometers northwest of Juba, the capital city of South Sudan. As previously reported [31], Bentiu and its surrounding settlements—including Dhorbor, Nhialdiu, Biel, and Rotriak—are situated in a region historically inhabited by agro-pastoralist communities. These populations traditionally practiced nomadic livestock rearing, primarily cattle herding, before the onset of large-scale oil and gas development in the area.

The study area is geographically positioned within a low-lying floodplain in the Nile Basin, which contributes to its vulnerability to seasonal inundation. The landscape is dominated by expansive wetlands and sluggish surface water flow, with elevated groundwater levels persisting even during the dry season. The hydrography of the region features a complex drainage network composed of dendritic, parallel, anastomosing, and braided channel systems. These interconnected drainage patterns eventually converge into major river channels, including the Bahr el Ghazal River, which runs adjacent to the town of Rubkona.

This unique hydrological and geomorphological setting plays a significant role in influencing the mobility and distribution of contaminants in the soil, particularly in areas adjacent to oil extraction infrastructure. The presence of both surface water and shallow groundwater systems necessitates careful monitoring, as pollutants may be transported across broader areas through water-mediated processes.

Sampling Sites and Methodology

To assess the environmental impact of oil and gas production on soil in Bentiu, samples were collected from Nahm River (upstream and downstream), Abuk River (near community center), and a control site with minimal industrial impact. Sampling was conducted at both upstream and downstream points near oil activity zones.

Samples from each site underwent laboratory testing at the South Sudan Bureau of Standards’ Laboratory, which ensured adherence to international quality standards. Parameters included heavy metals (specifically lead, cadmium, mercury, and chromium), and hydrocarbon concentrations. The heavy metals were analyzed using atomic absorption spectrophotometry (AAS), while hydrocarbon concentrations were measured using gas chromatography.

RESULTS AND DISCUSSION

A detailed analysis of soil quality in the Bentiu area was conducted, focusing on the concentrations of heavy metals (lead, cadmium, chromium, mercury) and hydrocarbons at various sampling locations. These pollutants were measured across different sampling intervals, providing a temporal view of soil contamination. Table 1 presents the concentrations of each pollutant for the Nahm River (upstream and downstream), Abuk River (near community center), and a control site located in a remote area presumed to have minimal industrial impact. This analysis is crucial for understanding the extent of pollution in areas impacted by oil production activities and comparing them to baseline levels at the control site.

Table 1: Soil Heavy Metal and Hydrocarbon Concentrations

Source: South Sudan Bureau of Standards and local environmental monitoring efforts in collaboration with Nilepet, Dar Petroleum, and Greater Pioneer Operating Company.

The table above provides a comprehensive overview of the concentrations of heavy metals (Lead, Cadmium, Chromium, Mercury) and hydrocarbons in the soil at various sites across Bentiu, Unity State, South Sudan. These measurements were taken over multiple sampling periods, reflecting both seasonal and spatial variations in contamination levels due to the oil and gas extraction activities in the region. The data includes results from the Nahm River, Bahr el Gazal (Abuk) River, the control site, and the newly added Khor Malual (Tarquer) River, offering a broad perspective on the extent of environmental impact caused by industrial activities.

Lead: Lead concentrations in the soils at all sites varied significantly. At the Nahm River (Upstream and Downstream) and the Bahr el Gazal (Abuk) River (Near Community), lead levels were generally high, especially during the mid-wet and post-wet seasons. For instance, lead levels in the Nahm River (Downstream) peaked at 48.03 µg/g in January 2024, while the Abuk River (Near Community) reached 39.28 µg/g in September 2024. In contrast, the control site (Remote Location) exhibited lower lead levels, with the highest concentration recorded as 44.65 µg/g in January 2024. Notably, Khor Malual (Tarquer) River, located in the vicinity of oil production, recorded 42.15 µg/g of lead in September 2024, indicating significant pollution consistent with the industrial activities in the area.

Cadmium: Cadmium levels were relatively lower across all sampling sites, but they still showed variations between sampling periods. The highest cadmium concentration was found in Nahm River (Upstream) during the dry season (2.51 µg/g) and in Nahm River (Downstream) during the post-wet season (1.62 µg/g). Khor Malual (Tarquer) River also exhibited cadmium contamination, with 1.40 µg/g during the post-wet season. In comparison, the control site had more stable levels, typically under 1 µg/g, confirming that cadmium contamination is largely concentrated around oil production areas.

Chromium: Chromium concentrations displayed a similar trend, with the highest levels recorded in Nahm River (Downstream) at 67.19 µg/g in November 2023. The levels were elevated in the Bahr el Gazal (Abuk) River as well, reaching 68.11 µg/g in January 2024. The Khor Malual (Tarquer) River exhibited a chromium concentration of 47.95 µg/g during the post-wet season, consistent with the observed pollution trends in other rivers affected by industrial activities. The control site, however, displayed the lowest chromium levels (24.38 µg/g in January 2024), reaffirming that chromium contamination is more significant in areas closer to oil production zones.

Mercury: Mercury concentrations remained relatively low across all sites, with the highest level observed in the Abuk River (near the Community) at 1.04 µg/g during the post-wet season. Nahm River (Upstream and Downstream) showed moderate mercury concentrations, peaking at 1.01 µg/g in November 2023 for the downstream section. Khor Malual (Tarquer) River had a mercury concentration of 0.72 µg/g in September 2024, indicating a steady level of contamination, albeit below the threshold for concern. The control site exhibited the lowest mercury concentrations, indicating that this pollutant is more concentrated near oil production activities.

Hydrocarbons: Hydrocarbon levels were the most concerning across all sites, with concentrations far exceeding the acceptable thresholds of 1 mg/kg. Nahm River (Upstream) exhibited hydrocarbons at 21.40 mg/kg during the dry season, with concentrations fluctuating to 31.84 mg/kg in September 2024 at the downstream site. Bahr el Gazal (Abuk) River (Near Community) had a high concentration of 34.09 mg/kg in September 2024. The newly included Tarquer River showed significant hydrocarbon pollution, reaching 31.85 mg/kg in September 2024. These levels highlight the persistent contamination from oil spills, leakage, and waste disposal from oil production activities. The control site, however, displayed the lowest hydrocarbon concentration (22.94 mg/kg in November 2023), further confirming that oil production activities are directly contributing to the contamination of surrounding areas.

The data in this table demonstrates the widespread and significant impact of oil production activities on the soil quality of Bentiu. Lead and chromium levels in particular indicate ongoing pollution from industrial operations, while hydrocarbons represent the highest form of contamination in these areas. Tarquer River, along with Nahm and Abuk rivers, are showing disturbing concentrations of these pollutants, which poses risks to both environmental and public health. The control site remains relatively unaffected, serving as a reference point for the extent of pollution near industrial sites.

A one-way ANOVA test (table 2) was conducted to determine whether significant differences existed in pollutant concentrations across the different sampling sites. This test helped to statistically assess if proximity to oil production activities correlated with higher contamination levels compared to the control site. For each pollutant—lead, cadmium, chromium, mercury, and hydrocarbons—the mean concentration values were compared across sites to identify any statistically significant variations. Following the ANOVA, post hoc tests were performed to specify which sites showed significant differences in contamination levels.

Table 2: Statistical Analysis – One-Way ANOVA for Soil Pollutants

The one-way ANOVA results indicate no statistically significant differences in the concentrations of lead, cadmium, chromium, mercury, or hydrocarbons across the different sampling sites (p > 0.05 for all pollutants). This suggests that, while variations in pollutant concentrations exist among sites, they are not statistically significant at the 95% confidence level. However, these findings underscore the importance of ongoing monitoring and site-specific analysis, as the environmental impact of contaminants might still vary with temporal and seasonal factors not captured by the ANOVA alone.

Table 3: Post Hoc Analysis – Tukey’s HSD Test for Lead Concentrations Across Sites

The post hoc Tukey’s Honest Significant Difference (HSD) test (table 3 above) was conducted to identify specific pairwise differences in lead concentration between sampling sites in Bentiu. The results presented in the table reveal mean differences between pairs of sites; however, all p-values were greater than the 0.05 significance level, indicating that none of the observed differences were statistically significant. This analysis suggests that, while lead concentrations varied somewhat across the sites, these differences were not pronounced enough to establish site-specific contamination effects with statistical confidence.

For example, the Abuk River – Near Community site showed a higher mean lead concentration compared to the Control Site – Remote Location, with a mean difference of 21.66 µg/g. However, the confidence interval for this difference (-11.92, 55.24) included zero, and the p-value of 0.2425 was above the 0.05 threshold, confirming that this difference is statistically non-significant. Similarly, when comparing the Nahm River – Downstream and Nahm River – Upstream sites, the mean difference was observed to be -9.11 µg/g, yet the p-value of 0.8207 further supported the absence of a statistically significant difference.

Across all pairwise comparisons, confidence intervals for the mean differences consistently included zero, reinforcing the lack of statistical significance between site-specific lead concentrations. This indicates that while mean lead levels differ slightly from one site to another, these variations are insufficiently distinct to conclude that certain sites are more heavily impacted by lead contamination than others in a statistically meaningful way.

The post hoc analysis supports the overall findings from the ANOVA, demonstrating no statistically significant variation in lead concentrations across sites. This implies that lead contamination is relatively evenly distributed among the sampled locations

Our analysis, found out that various impacts from evenly distribution of heavy metals and hydrocarbons in the soil. Accumulation of this pollutants to the soil causes health risk to human. This is in line with studies by [32]. Also there has been an increase in soil acidification and alteration of pH in the soil, aligning with studies undertaken during Small Arms Survey [33].

Accumulation over time of these heavy metal, and chemicals used during oil and gas extraction, there has been increase in loss of soil fertility and agricultural productivity of the soil. This is collaborated in the publication by UNEP [34], that found out decline in crop yields, loss of grazing lands, and increased food insecurity due to unusable soils. With continuous accumulation of heavy metals, poses long term ecological and health risk.

Figure 1. Photographs (top two rows) and Sentinel-2 satellite images (January 6th, 2020, bottom row) of oil spills in the two affected sites in the study area: Oil Spill-I (left) and Oil Spill-II (right). Source of oil spill locations: (Stieglitz, 2020). Source of satellite image: European Space Agency (ESA). Source of locations of vegetation fires (triangles in the maps): NASA Fire Information for Resource Management System (FIRMS).

Source: Stieglitz, 2020; European Space Agency (ESA); NASA Fire Information for Resource Management System (FIRMS).

The provided image offers a combination of visual and satellite-based insights into soil contamination in Bentiu, Unity State, South Sudan. It consists of both photographic and satellite images, highlighting the severe environmental impact of oil production in the region. The top-left and top-right images display direct photographs of oil spills and their proximity to other disturbed areas such as roads and vegetation, providing a clear view of the physical effects of oil contamination on the landscape. These photographs underscore the extent of contamination, showing oil spreading across the land and affecting surrounding ecosystems.

The lower part of the image combines satellite imagery from NASA FIRMS fire detection data (2018, 2019, 2020), showing areas affected by oil spills and fire events. The satellite image on the left shows an oil spill marked as “Oil Spill I,” as well as features such as water ponds, roads, and pipelines. These features, identified using labels, help track the extent of the contamination and its relation to oil extraction infrastructure. Similarly, the image on the right highlights a different oil spill area, marked as “Oil Spill II,” and further depicts the burnt vegetation that likely resulted from fire events, a common consequence of oil spill incidents. These events have contributed significantly to soil and environmental degradation in the region.

Together, the visual and satellite data paint a comprehensive picture of soil contamination in Bentiu, emphasizing the spread of oil contamination through both surface-level photos and aerial observations. The images provide important context for understanding the long-term environmental damage caused by oil extraction activities, including soil pollution, destruction of vegetation, and the potential for further ecosystem degradation. This combination of images can be used to complement field data and analyses, providing a clear visual representation of the soil contamination and its broader ecological implications.

The soil contamination shown is directly linked to the oil and gas production activities in Bentiu, and the images offer an essential tool for identifying contamination hotspots, assessing the environmental impact, and planning future environmental management strategies

CONCLUSION

Oil and gas production activities pose significant risks to soil health and integrity. The processes involved, such as drilling, hydraulic fracturing, and transportation, can lead to soil contamination through spills, leaks, and the improper disposal of drilling fluids and produced water. These contaminants, including hydrocarbons and heavy metals, can alter soil chemistry, reduce fertility, and disrupt microbial communities essential for nutrient cycling. Our study noted, no statistically significant differences in their concentrations between the compared groups or conditions. This suggests that oil and gas extraction, did not lead to measurable differences in soil contamination levels for these pollutants at a statistically significant level. However, accumulation of these heavy metals and hydrocarbons had impacts on soil fertility, alteration of pH, reduction of agricultural crop yield and long term ecological and health risk.

RECOMMENDATION

Although our study did not measurable differences in contamination levels and no measurable impacts, does not rule out potential localized effects or long-term impacts, and further investigation may still be warranted depending on site conditions and exposure duration.

1. The study recommends further complementary studies, considering other forms of environmental assessments such as biological indicators (e.g., vegetation health, microbial diversity) or long-term ecological impact studies, which might reveal effects not captured by current analyses.
2. Further, we recommended the development and implementation of precautionary measures, which, despite the current absence of statistically significant pollution, precautionary environmental management should still be practiced. Oil and gas operations near communities and water resources should continue to follow best practices for waste handling, spill prevention, and site rehabilitation.
3. Also, the researcher recommended continued periodic monitoring, which will help detect any emerging trends or delayed environmental impacts from oil and gas activities, especially in sensitive areas near communities and water bodies.
4. The study recommends the urgent need for expanded and more granular environmental monitoring, including higher sampling frequency and additional ecological indicators, to more accurately characterize pollution dynamics and inform targeted remediation strategies

ACKNOWLEDGEMENT

The authors acknowledge the Regional Universities Forum for Capacity Building in Agriculture (RUFORUM)for its support in facilitating this research.  Additionally, the authors appreciate the Government of Kenya and Government of South Sudan for its support, which enabled access to necessary data, research facilities and relevant stakeholders. We extend our gratitude to the reviewers for their constructive feedback, which helped improve the quality of this work.

Conflict of Interest

The authors have no conflicts of interest to disclose

REFERENCES

1. Gauthier, M. (2025). Operationalizing epistemic justice: Participatory 3D Modelling in conservation practice. Academia Environmental Sciences and Sustainability, 2(2). https://doi.org/10.20935/AcadEnvSci7663
2. Wan, Y., Liu, J., Zhuang, Z., Wang, Q., & Li, H. (2024). Heavy Metals in Agricultural Soils: Sources, Influencing Factors, and Remediation Strategies. Toxics, 12(1), 63. https://doi.org/10.3390/toxics12010063
3. Halanych, K. M., Ainsworth, C. H., Cordes, E. E., Dodge, R. E., Huettel, M., Mendelssohn, A., Murawski, S. A., Paris-Limouzy, C. B., Schwing, P. T., Shaw, R. F., & Sutton, T. (2021). Oceanography, 34(1), 152–163. https://doi.org/10.5670/oceanog.2021.123
4. Alloway, B. J. (2013). Heavy metals in soils: Trace metals and metalloids in soils and their bioavailability (Vol. 22). Springer.
5. Sutormin, O. S., Goncharov, A. S., Kratasyuk, V. A., Petrova, Y. Y., Bajbulatov, R. Y., Yartsov, A. E., & Shpedt, A. A. (2024). Effects of oil contamination on range of soil types in Middle Taiga of Western Siberia. Sustainability, 16(24), 11204. https://doi.org/10.3390/su162411204
6. Daâssi, D., & Qabil Almaghribi, F. (2022). Petroleum-contaminated soil: Environmental occurrence and remediation strategies. 3 Biotech, 12(6), 139.     https://doi.org/10.1007/s13205-022-03198-z
7. Magok, A. B. (2021). Hydrocarbon pollution in surface waters of Unity State, South Sudan. South Sudan Journal of Environmental Research, 2(1), 21–30.
8. Kabata-Pendias, A., & Mukherjee, A. B. (2007). Trace elements from soil to human. Springer.
9. Khan, S., Cao, Q., Zheng, Y. M., Huang, Y. Z., & Zhu, Y. G. (2008). Health risks of heavy metals in contaminated soils and food crops irrigated with wastewater in Beijing, China. Environmental Pollution, 152(3), 686–692.
10. United Nations Environment Programme. (2011). South Sudan: First state of environment and outlook report 2011. United Nations Environment Programme.
11. Elkamil, M. A., Ahmed, T. A., & Musa, Y. A. (2016). Assessment of heavy metals contamination in soils around oil production facilities in Sudan. Journal of Environmental Science and Technology, 9(4), 343–351.
12. Tchounwou, P. B., Yedjou, C. G., Patlolla, A. K., & Sutton, D. J. (2012). Heavy metal toxicity and the environment. Experientia Supplementum, 101, 133–164.
13. Nwilo, P. C., & Badejo, O. T. (2006). Impacts and management of oil spill pollution along the Nigerian coastal areas. Administering Marine Spaces: International Issues, FIG Publication No. 36, 119–128. International Federation of Surveyors
14. Chikere, C. B., Ekwuabu, C. B., & Chikere, B. O. (2012). Bacterial diversity and community dynamics of a crude oil-polluted soil undergoing bioremediation. African Journal of Biotechnology, 11(44), 10454–10462.
15. Cermak, L., et al. (2020). Effects of PAHs on soil microbial communities: A review. Ecotoxicology and Environmental Safety, 192, 110273.
16. Zhou, S., et al. (2017). Environmental effects of oil sands development: Soil contamination in Alberta. Environmental Science & Technology, 51(20), 11620–11629.
17. Das, N., & Baruah, R. (2013). Biodegradation of petroleum hydrocarbon pollutants in soil by microbial consortium. Indian Journal of Biotechnology, 12(3), 456–463.
18. Nriagu, J. O., et al. (2016). Oil pollution in the Niger Delta. Science of the Total Environment, 572, 1343–1352.
19. Ekpo, B. O., et al. (2021). Distribution and ecological risk assessment of PAHs in soils of the Niger Delta. Environmental Science and Pollution Research, 28, 20012–20025.
20. Tobiszewski, M., & Namieśnik, J. (2012). PAHs in the environment: Sources, fate and behavior. Science of the Total Environment, 438, 347–368.
21. O’Sullivan, F., & Paltsev, S. (2021). The environmental footprint of shale gas in the U.S. Nature Sustainability, 4(2), 98–105.
22. Laliteshwari Bhardwaj, Bhaskar Reddy, Arun Jyoti Nath, Suresh Kumar Dubey, (2024) Influence of herbicide on rhizospheric microbial communities and soil properties in irrigated tropical rice field, Ecological Indicators, Volume 158,https://doi.org/10.1016/j.ecolind.2023.111534.
23. Bell, T. H., et al. (2016). Impact of oil drilling on soil microbial communities in the North Sea region. Environmental Microbiology Reports, 8(4), 505–514.
24. Margesin, R., et al. (2003). Bioremediation of hydrocarbon-contaminated soil: Evaluation of microbial response. Chemosphere, 50(6), 775–787.
25. Zoback, M. D., Kitasei, S. D., & Copithorne, B. (2010). Addressing the environmental risks from shale gas development. Worldwatch Institute Report, 1, 1–26.
26. Norwegian Ministry of Petroleum and Energy. (2019). Petroleum Act. Oslo, Norway.
27. Weber, B., & Kriesky, J. (2018). The energy boom and environmental justice. Environmental Justice, 11(3), 89–94.
28. Parlee, B., et al. (2012). Traditional knowledge in environmental assessments: The role of knowledge in the development of northern energy resources. Ecology and Society, 17(4), 11.
29. Tsegaye, D., Vedeld, P., & Moe, S. R. (2015). Strengthening the resiliency of dryland forest-based livelihoods in Ethiopia and South Sudan: A review of literature on the interaction betweendryland forests, livelihoods and forest governance. Norwegian University of Life    Sciences
30. Ali, M. M., et al. (2018). Environmental pollution from oil activities in South Sudan. Journal of Environmental Protection, 9(1), 72–85.
31. Bul, K., Mugendi, D., & Latema, S. (2025). The socio-economic implications of oil and gas production to local communities in Bentiu Unity State, South Sudan. International Journal of Social Sciences and Humanities Invention, 12(04), 8530–8540. https://doi.org/10.18535/ijsshi/v12i04.02
32. Tyokumbur, E.T., et al. (2022). “Environmental and public health assessment of oil-polluted sites in South Sudan.” Environmental Monitoring and Assessment, 194(3), 1–15. DOI: 1007/s10661-022-09880-y.
33. Small Arms Survey (2020). “Oil, Conflict, and Security in South Sudan.” HSBA Report No. 24, Geneva: Small Arms Survey.
34. United Nations Environment Programme (UNEP). (2020). “Environmental Scoping Mission Report: South Sudan.” Nairobi: UNEP.