Spill Site Research Articles

Soil gas gradient method for estimating natural source zone depletion rates of LNAPL and specific chemicals of concern

This paper presents a simplified approach for the soil gas gradient method for estimating natural source zone depletion (NSZD) rates of specific contaminants of concern (COCs) at sites contaminated by light non-aqueous phase liquids (LNAPL). Traditional approaches to quantify COC-specific NSZD rates often rely on numerical or analytical reaction-transport models that require detailed site-specific data. In contrast, the proposed method employs simple analytical solutions, making it more accessible to practitioners. Specifically, it requires only the maximum soil gas concentration, the effective diffusion coefficient, and the diffusive reaction length calculated from vertical soil gas concentration profiles. The simplified approach was validated against a reactive transport numerical model reported in the literature, showing consistent results within the same order of magnitude for BTEX NSZD rates at a gasoline spill site in South Carolina. Further validation using a larger dataset involved comparing NSZD rate estimates for benzene and total petroleum hydrocarbons (TPH) against those obtained using BioVapor, utilizing empirical soil gas data from the USEPA Petroleum Vapor Intrusion Database. Results demonstrated a strong correlation between NSZD rates and maximum soil gas concentrations, allowing the development of a rapid screening approach based only on the measured soil gas concentrations and literature values for diffusion coefficients and diffusive reaction lengths. This approach aligned well with previous modeling studies and was consistent with literature values for TPH NSZD rates. Overall, both the simplified and screening approaches offer practical, easy-to-use tools for evaluating temporal variability in natural attenuation rates, supporting baseline assessments and ongoing performance evaluations of remediation at LNAPL sites.

Sorbents based on foamed phosphate glass for collecting petroleum oil products from contaminated soils and water surfaces

Relevance. The need to clean from pollution soils and water areas contaminated with oil and chemical industry wastes. Physico-chemical methods are one of the effective ways of cleaning, provided that sorbents are applied in time to collect contaminants from the surface of water areas and landscapes. Sorption is the most efficient and cost-effective method for relatively small scale pollution. Despite the variety of existing sorbents, in most cases when cleaning up accidental spills, first of all, economic benefits and oil capacity value of the sorbent are guided. However, such essential criteria as: 1) main purpose (type of polluted surface and nature of pollution); 2) physical and chemical properties, including structural characteristics and acid-base adsorption centers; 3) peculiarities of oil or other pollutants adsorption. Taking into account these factors, it is possible to develop and improve the formulation of sorbents based on phosphate foams. Introduction of various modifying additives into material composition is likely to expand their field of application. Aim. Development of formulation and technological features of obtaining new phosphate sorbents in relation to their intended purpose: for collecting oil and petroleum product spills from soil or water surfaces. Methods. Gravimetric, microscopic spectroscopic, statistical and comparative methods. Results and conclusions. The authors have compared sorbents no. 1 and 2 in terms of physical and chemical properties, morphology and cleaning efficiency. Based on our laboratory studies, we concluded that sorbent no. 1 is better suited for sorption from aqueous surfaces and sorbent no. 2 is better suited for soil cleaning. Both sorbents have the potential to improve their technological properties. This allows refining the formulation of these materials with further testing in laboratory and field conditions, for example, at oil spill sites. For this purpose, it is possible to change the material composition using a different foaming agent, applying modifying additives and varying the temperature mode of firing. Development of new compositions and methods of sorbent foaming will make it possible to select optimal characteristics for each type of contamination. The author proposed as well to create phosphate biosorbent obtained by immobilization of fungi and bacteria on the surface of highly porous carrier. In this case, after sorption of pollution, adsorbed substances will undergo biodegradation with the formation of safe products, and the sorbent will perform the role of fertilizer.

Regional Assessment of Groundwater Contamination Risk from Crude Oil Spillages in the Niger Delta: A Novel Application of the Source-Pathway-Receptor Model

AbstractOnshore oil spills are known for their disastrous environmental impacts and potential to cause lasting damage to underlying groundwater. The Niger Delta is particularly vulnerable to widespread spillages linked to extensive oil exploration, transportation, and theft-related incidents. This research employed a geospatial approach in formulating risk equations, based on the source-pathway-receptor (S-P-R) model using multiple openly available data sets, to assess groundwater contamination risk in the Niger Delta Region (NDR), Nigeria. To develop the overall risk equation, the study combined fourteen thematic data layers including the volume of oil spilled, type of spill, slope, elevation, proximity to spill site, pipeline, oil wells and streams, drainage density, mean annual precipitation and population density. These layers were integrated into source potency, pathway transmissivity, and receptor susceptibility. The NDR was systematically categorized into low, moderate, and high groundwater risk zones. The delineation revealed that high-risk zones predominantly span the central areas, extending from southeast to northwest, effectively encircled by regions of low to medium risk located in both the northern and southern extents of the delta. The efficacy of the risk model was corroborated by existing knowledge. Moderate to high-risk zones were found to be in about 16% of the NDR, revealing previously unknown areas of risk. This spatial configuration underscores a significant gradient in contamination risk across the NDR, with the central corridor emerging as a critical focus for groundwater protection and remediation efforts. In line with UN Sustainable Development Goal (SDG) #6, this study recommends targeted strategies to ensure clean water provision in these identified high-risk areas. By leveraging the S-P-R model within this complex and sensitive ecological area, this research both advances environmental risk assessment and sets a precedent for future large-scale environmental risk assessments utilizing open-source data.

Integrated geophysical and geochemical characterization of hydrocarbon contaminated site in Erhoike-Kokori, Southern Nigeria

The effectiveness of geophysical and geochemical methods in delineating hydrocarbon contamination in a spill site is carried out around theErhoike flow station in Kokori, Ethiope East LGA, Delta State. Wenner array was used for the transverse in acquiring the data which spanned a transverse of 200m and 3D model resistivity images were obtained from the inversion and presented in horizontal depth slices. Well water samples were also taken for Total Petroleum Hydrocarbon (TPH) content while soil samples from the location were also taken for Porosity and coefficient of permeability. The result of the 3D horizontal depth slices in the location reveals that Erhoike is impacted with hydrocarbon plume to a depth of 31.7m. The concentration of TPHCs from the water analysis shows that the wells around the suspected zones are affected by hydrocarbon. The laboratory tests for porosity (Փ ) and coefficient of permeability (k) for the soil samples are indicative of sand/silty sand which thus allows the flow of PHCs plume to the soil and groundwater in the study area. The results of the study have shown that the soil is permeable and porous which would allow the passage of the leaked and spilled PHCs through the soil to groundwater where the PHCs could mix, float and sink into groundwater. The 3D analysis revealed the presence of PHCs up to a depth of 33.7m but prominent at a depth of 10m which indicates the presence of PHCs in the wells. The hydrochemical analysis also proved the same results as that of the 3D which authenticated the reliability of the method used in the study.

Accelerated technology for cleaning oil-contaminated soils

Relevance. The uniqueness of the practical application of accelerated and environmentally safe technology for the reclamation of oil–polluted lands, which uses local mineral raw materials, a consortium of autochthonous hydrocarbon-oxidizing bacteria with multifunctional positive properties, effective phytomeliorants, is theoretically substantiated. Hydrocarbon pollution is eliminated directly at the spill site, and the rate ofreturn of disturbed soils to agricultural circulation is 3–4 times faster than traditional methods.Methods. Objects of research: mechanically activated bentopowder and nanobentonite, a consortium of hydrocarbon-oxidizing bacteria composed of three autochthonous strains, soil leached chernozem, spring wheat, Devonian oil. The concentration of oil pollution at the site was 6.4%. Bentopowder and nanobentonite were introduced in doses of 6.0 t/ha and 0.3 t/ha, respectively. Sampling was carried out with a sampler on the 0th, 15th, 30th, and 90th days.Results. The optimal doses of application of bento powder and nano bentonite to disturbed soil above the average pollution level (6.0 t/ha and 0.3 t/ha respectively) are recommended. After 15 days, the level of contamination is halved (to 51.1 g/kg and 40.8 g/kg with benton powder and nanobentonite respectively). Removal of the introduced mineral sorbent is not required, since it later becomes a source of mineral nutrition for autochthonous microorganisms-destructors and a soil improver. At the second innovative stage, a consortium formed from effective strains and adapted to specific conditions is used. The strains of the consortium fit into an ecological niche, adapt and begin to actively develop, utilizing oil and petroleum products. After a month, the level of contamination decreases to 19.2 g/kg and 9.2 g/kg with the addition of benton powder and nanobentonite respectively.

A multi-criteria simulation-optimization coupling approach for effective emergency response in marine oil spill accidents

Effective marine oil spill responses are vital to reduce environmental, societal, and economic damage. This study developed a Multi-Criteria Emergency Response System (MC-ERS) to comprehensively evaluate response efficiency, operational costs, and environmental losses. The proposed system integrates dynamic multiphase simulation of oil weathering and oil cleanup processes and further provides effective planning for multi-stage resource allocation through system optimization. The developed weight-sum model improved the performance of response operations by reducing the complexity of multi-criteria decision-making. Particle Swarm Optimization (PSO) was chosen as the foundational optimization algorithm due to its efficiency in rapid convergence and suitability for complex problems. From extensive comparisons of PSO variants across benchmark functions and inertia strategies, the C-PSO algorithm was developed, demonstrating enhanced optimization performance for MC-ERS. The developed modelling system performance was demonstrated and evaluated through a representative case study. The optimization plan coordinated resource allocation from onshore warehouses to harbors and spill sites, balancing oil recovery efficiency, costs, and ecological losses. Optimized results indicate an oil recovery of up to 76.50% in five days. Additionally, the system cuts costs by 3.45% and environmental losses by 15.75%. The findings enhance the efficiency of marine oil spill emergency response and provide support for such incidents.

A DiffeRential Evolution Adaptive Metropolis (DREAM)-based inverse model for continuous release source identification in river pollution incidents: Quantitative evaluation and sensitivity analysis

The identification of continuous pollution sources for rivers is of great concern for emergency response. Most studies focused on instantaneous river pollution sources and associated incidents. There is a dire need to address continuous pollution sources, as pollutant discharge may impose a major impact on the water ecosystem. Therefore, in this study, a novel inverse model is proposed to identify the continuous point sources in river pollution incidents that would estimate the source strength, location, release time, and spill time. The proposed inverse model combines the advanced DiffeRential Evolution Adaptive Metropolis (DREAM) algorithm and the forward transport advection-dispersion equation to infer the posterior probability distribution of source parameters for quantifying uncertainties. In addition, the performance of the DREAM-based model is compared with those of the Metropolis-Hastings (MH)-based and genetic algorithm (GA)-based models. The results show that the DREAM-based model performs accurately for both the hypothetical and the field tracer cases. The comparative analysis shows that the DREAM-based model performs better in saving computation time, improving the accuracy of results, and reconstructing pollutant concentrations. Observation errors significantly influence the accuracy of the identification results from the DREAM-based model. In addition, a comprehensive sensitivity analysis of the DREAM-based model is conducted. The identification results from the DREAM-based model are sensitive to the dispersion coefficient and river velocity. The accuracy of the inverse model could be improved by increasing the monitoring number and by monitoring locations closer to the spill site. The findings of this study can improve decision-making during emergency responses to sudden river pollution incidents.

Oil spill soil remediation using thermal desorption: Project synthesis and outcomes

AbstractFarmland within the Williston Basin of North Dakota was the site of the largest terrestrial oil spill to date in the United States in 2013. Over 3200 m3 of oil was released into the topsoil and subsoil, creating a risk to soil, water, and air resources. The purpose of this document is to provide a summary of results from a 7‐year project investigating the impacts of how thermal desorption (TD), the method used to remediate topsoil and subsoil, impacted contaminant reduction, soil function, and plant productivity simultaneously with site remediation. Soil disturbance and TD decreased soil organic matter and microbial communities, resulting in decreased soil function and plant production. However, TD did not reduce soil microbial recovery 4 years after treatment. Blending TD‐treated soil with uncontaminated topsoil appeared to minimize these negative effects and promote recovery of soil function. These findings provided critical information to stakeholders in the understanding of soil remediation and reclamation in this region.

Total and Bioaccesible Metal Concentrations in Surficial Sediment Affected by a Mining Spill: Case of Sonora River, Northwest of Mexico

ABSTRACT Metals and metalloids are persistent contaminants that are associated with many anthropogenic activities and mining in particular. On August 6, 2014, approximately 40,000 m3 of toxic acid mining waste was spilled from the Buena Vista del Cobre Copper Mine. The spill affected 220 km of the Sonora River Basin (SRB) over a surface area of ~ 30,000 km2. This study evaluated the total and bioaccessible concentrations of six metals and their enrichment in surficial sediments in spill and no-spill sites in the SRB. All metal concentrations showed significant seasonal and spatial variation (p < .05) in surficial sediments, with a general distribution of Al > Fe > Mn > Zn > Cu > Pb. The total and bioaccessible concentrations of the elements in this study were similar between spill and no-spill sites. Variations in element levels were associated with re-suspension and advection related with rain run-off, and the element concentrations were associated with the high natural concentrations in surficial sediments found throughout the SRB (considering the predominant soil types). The enrichment factor (EF) indicated minor to moderate-severe enrichment of Fe and Mn, minor to severe enrichment of Pb and Zn, and moderate-severe to very severe enrichment of Cu. The bioaccessible percentages of metals with respect to the total concentrations varied from 0.23 to 69.9%. The Sediment Quality Guidelines criteria indicated that adverse effects on biota that are mainly due to Cu levels are potentially present. Chronic exposure to metals may produce intermediate and long-term effects on the metabolic responses of biota.

Application of novel nanobubble-contained electrolyzed catalytic water to cleanup petroleum-hydrocarbon contaminated soils and groundwater: A pilot-scale and performance evaluation study

Soil and groundwater contamination caused by petroleum hydrocarbons is a severe environmental problem. In this study, a novel electrolyzed catalytic system (ECS) was developed to produce nanobubble-contained electrolyzed catalytic (NEC) water for the remediation of petroleum-hydrocarbon-contaminated soils and groundwater. The developed ECS applied high voltage (220 V) with direct current, and titanium electrodes coated with iridium dioxide were used in the system. The developed ECS prototype contained 21 electrode pairs (with a current density of 20 mA/cm2), which were connected in series to significantly enhance the hydroxyl radical production rate. Iron-copper hybrid oxide catalysts were laid between each electrode pair to improve the radical generation efficiency. The electron paramagnetic resonance (EPR) and Rhodamine B (RhB) methods were applied for the generated radical species and concentration determination. During the operation of the ECS, high concentrations of nanobubbles (nanobubble density = 3.7 × 109 particles/mL) were produced due to the occurrence of the cavitation mechanism. Because of the negative zeta potential and nano-scale characteristics of nanobubbles (mean diameter = 28 nm), the repelling force would prevent the occurrence of bubble aggregations and extend their lifetime in NEC water. The radicals produced after the bursting of the nanobubbles would be beneficial for the increase of the radical concentration and subsequent petroleum hydrocarbon oxidation. The highly oxidized NEC water (oxidation-reduction potential = 887 mV) could be produced with a radical concentration of 9.5 × 10−9 M. In the pilot-scale study, the prototype system was applied to clean up petroleum-hydrocarbon polluted soils at a diesel-oil spill site via an on-site slurry-phase soil washing process. The total petroleum hydrocarbon (TPH)-contaminated soils were excavated and treated with the NEC water in a slurry-phase reactor. Results show that up to 74.4% of TPH (initial concentration = 2846 mg/kg) could be removed from soils after four rounds of NEC water treatment (soil and NEC water ratio for each batch = 10 kg: 40 L and reaction time = 10 min). Within the petroleum-hydrocarbon plume, one remediation well (RW) and two monitor wells (located 1 m and 3 m downgradient of the RW) were installed along the groundwater flow direction. The produced NEC water was injected into the RW and the TPH concentrations in groundwater (initial concentrations = 12.3–15.2 mg/L) were assessed in these three wells. Compared to the control well, TPH concentrations in RW and MW1 dropped to below 0.4 and 2.1 mg/L after 6 m3 of NEC water injection in RW, respectively. Results from the pilot-scale study indicate that the NEC water could effectively remediate TPH-contaminated soils and groundwater without secondary pollution production. The main treatment mechanisms included (1) in situ chemical oxidation via produced radicals, (2) desorption of petroleum hydrocarbons from soil particles due to the dispersion of nanobubbles into soil pores, and (3) enhanced TPH oxidation due to produced radicals and energy after nanobubble bursting.

Photochemical mobilization of dissolved hydrocarbon oxidation products from petroleum contaminated soil into a shallow aquifer activate human nuclear receptors

Elevated non-volatile dissolved organic carbon (NVDOC) concentrations in groundwater (GW) monitoring wells under oil-contaminated hydrophobic soils originating from a pipeline rupture at the National Crude Oil Spill & Natural Attenuation Research Site near Bemidji, MN are documented. We hypothesized the elevated NVDOC is comprised of water-soluble photooxidation products transported from the surface to the aquifer. We use field and laboratory samples in combination with complementary analytical methods to test this hypothesis and determine the biological response to these products. Observations from optical spectroscopy and ultrahigh-resolution mass spectrometry reveal a significant correlation between the chemical composition of NVDOC leached from photochemically weathered soils and GW monitoring wells with high NVDOC concentrations measured in the aquifer beneath the contaminated soil. Conversely, the chemical composition from the uncontaminated soil photoleachate matches the NVDOC observed in the uncontaminated wells. Contaminated GW and photodissolution leachates from contaminated soil activated biological targets indicative of xenobiotic metabolism and exhibited potential for adverse effects. Newly formed hydrocarbon oxidation products (HOPs) from fresh oil could be distinguished from those downgradient. This study illustrates another pathway for dissolved HOPs to infiltrate GW and potentially affect human health and the environment.

Biogeochemical modelling to assess benzene removal by biostimulation in aquifers containing natural reductants.

Biostimulation of aquifers contaminated with gasoline spills is vigorously affected by the biogeochemical environment existing there. In this study, biostimulation of benzene is simulated using a 2D coupled multispecies biogeochemical reactive transport (MBRT) model. The model is implemented at an oil spill site near a hypothetical aquifer containing natural reductants. Multiple electron acceptors are introduced to promote faster biodegradation rate. However, after reaction with natural reductants, it reduces the number of available electron acceptors, acidifies the subsurface environment, and inhibits bacterial growth. These mechanisms are assessed using seven coupled MBRT models sequentially. The finding of the present analysis reveals that biostimulation has caused a substantial drop in concentration of benzene and is efficient in reducing its penetration depth. The results also shows that the intervention of natural reductants in the biostimulation process is slightly diminished by pH adjustment of aquifers. When the pH level in aquifer changes from acidic pH 4 to neutral pH 7, it is observed that the biostimulation rate of benzene as wellas microbial activity increases. Electron acceptors consumption is more at neutral pH. Overall, it can be inferred from zeroth-order spatial moment and sensitivity analyses that retardation factor, inhibition constant, pH, and dispersivity in vertical direction significantly affect benzene biostimulation in aquifers.

Effect of Grain Size on Radionuclide Content in Sediment Samples from Kolo Creek, Bayelsa State, Nigeria

The effect of grain sizes on radionuclide concentration in soil and sediment samples from Kolo creek, Bayelsa State was investigated using gamma spectroscopy. Eight (8) samples of sediment were collected around the oil spill site of the creek. All the samples were separated into four different grain sizes, A (0.5mm), B (1mm), C (1.5mm) and D (2mm), making a total of 32 sediment. The activity concentration in sediment samples of grain sizes 0.5 mm, 1.0mm, 1.5mm and 2mm were determined. In sediment samples of grain sizes 0.5mm(A), the activity concentration of 226Ra , 232Th and 40K ranges from 2.24 to 20.032.43Bq/kg, 3.21 to 5.591.32 Bq/kg and 24.46 4.06 to 795.99 6.20 Bq/kg respectively. For grain size of 1.0mm (B) the activity concentration of 226Ra, 232Th and 40K varies from 2.661.30 to 26.64Bq/kg, 2.19 0.95 to 33.47 Bq/kg and 43.38 to 739.21Bq/kg respectively. For grain size of 1.5mm (C) the activity concentration of 226Ra, 232Th and 40K varies from 4.401.09 to 33.93± 3.65 Bq/kg, 2.14±1.72 to 26.15±5.3 Bq/kg and 39.90±3.54 to 471.36±6.12 Bq/kg respectively. For grain size of 2.0 mm (D) the activity concentration of 226Ra, 232Th and 40K varies from 4.81±1.84 to 40.29±2.50 Bq/kg, 2.19±1.40 to 83.20±3.90 Bq/kg and 39.01 ±4.00 to 497.56±5.87Bq/kg respectively. The result obtained shows there was no clear trend in variation of activity concentration with grain sizes. The mean values obtained are below the world average of 35, 30 and 400 Bq/kg for 226 Ra, 232Th and 40K for grain sizes of 0.5, 1.0, 1.5 and 2.0 mm respectively in all the communities except samples from Kolo that recorded 471.36±6.12 to 795.99±6.44 Bq/kg in all the grain sizes. Radiological risk parameters such as Absorbed Dose Rate, Annual Effective Dose Equivalent, Annual Gonadal Dose Equivalent, Annual Utility Index, Radioactivity Level Index, Hazard Indices and Excess Life Cancer Risk were estimated and values were found to be within the word average. From this study, the sediment of the given grain sizes will pose no radiological health risk if used in farming and in building construction.

Disaster Response and Recovery Practices among Oil Spill Impacted Communities in Selected States in Niger Delta Region, Nigeria

The study examined the disaster response and recovery practices among oil spill impacted communities in selected states in Niger Delta region of Nigeria. The study cut-across six (6) LGAs from three (3) states, that is, Akwa Ibom, Bayelsa and Delta while questionnaire was administered among 400 respondents with return rate of 94% amounting to 375 valid questionnaires. The returned questionnaires were analysed using descriptive statistics and ANOVA for the study hypotheses. The outcome of the study indicated that abandonment of spilled site (21.3%) is the most adopted response practice while in-situ burning of oil (22.4%) and scooping of the spilled oil (22.1%) as the major recovery practices. Statistically, there was no significant difference in post-disaster practices such as disaster response (where p &gt; 0.05, p= 0.116) and recovery (where p &gt; 0.05, p= 0.775) across the states. In conclusion, there is need for synergy among all the multi-agency and involvement of the community in deriving long lasting post-disaster practices. Harmonizing several overlapping legislations and governance institutions was recommended.

Study of the evolution of oil spill sites based on high-resolution satellite images: the case of the Samotlor field

A methodology for visual interpretation of accidental oil spills using satellite images from the WorldView-3 satellite equipped with short-wave infrared (SWIR) channels is proposed, with verification using multi-temporal very-high-resolution images in the Google Earth system. The analysis of the images of four large oil spills in the southeastern part of the Samotlor field made it possible to study the degradation changes in different types of vegetation and the processes of its self-recovery for 2017–2022. The comparison of the results of image analysis with the data from field studies reveals their good agreement and the need for further development of methods for remote monitoring of oil spills using the SWIR range.

Environmental and health risks assessment of n-alkanes and BTEX in Eze Iyi River at oil spill site in Isuikwuato, Abia State, Nigeria.

The environmental and health risks of n-alkanes and benzene, toluene, ethylbenzene, and xylene (BTEX) in Eze-Iyi River at Isuikwuato oil spill site were evaluated. The water samples (60) were collected from upstream and downstream during the dry and rainy seasons. Concentrations of n-alkanes and BTEX were determined using a gas chromatograph coupled with a flame ionization detector. The percentage recovery of 87.3% and 92.0% was obtained for n-alkanes and BTEX in the water sample. The environmental risk analysis for n-alkanes and BTEX showed 80% of the water samples had a ratio greater than 1 indicating environmental risk in the area. Hydrocarbon source identification using biomarkers indicates that the n-alkane (nC16) dominant during the dry and rainy seasons was from anthropogenic/biogenic source, while nC14 and nC17 were from microbial and marine algae biogenic sources, respectively. The benzene levels in 100% (downstream) and 80% (upstream) of samples in the dry season and 40% (upstream) and 100% (downstream) of samples in the rainy season were above the WHO permissible limit of 0.01mg/L for drinking water. The health risk index of n-alkanes during the dry season for children (upstream) was greater than 1 signifying adverse health risk. Therefore, consumption of water from the river should be discouraged and routine monitoring by regulatory authorities maintained to checkmate the build-up of BTEX and n-alkanes.

Levels of Arsenic, Cadmium, and Mercury in Urine of Indigenous People Living Close to Oil Extraction Areas in the Peruvian Amazon.

Levels of Arsenic, Cadmium, and Mercury in Urine of Indigenous People Living Close to Oil Extraction Areas in the Peruvian Amazon.

Application of Vegetation Indices for Detection and Monitoring Oil Spills in Ahoada West Local Government Area of Rivers State, Nigeria

The study evaluated the environmental effects of an oil spill in Joinkrama 4 and Akimima Ahoada West LGA, Rivers State, Nigeria, using various vegetation indices. Location data for the spill were obtained from the Nigeria Oil Spill Detection and Response Agency, and Landsat imagery was acquired from the United States Geological Survey. Three soil samples were collected from the affected area, and their analysis included measuring total petroleum hydrocarbons (TPH), total hydrocarbons (THC), and polycyclic aromatic hydrocarbons (PAH). The obtained data were processed with ArcGIS software, utilizing different vegetation indices such as the Normalized Difference Vegetation Index (NDVI), Atmospheric Resistant Vegetation Index (ARVI), Soil Adjusted Vegetation Index (SAVI), Green Short Wave Infrared (GSWIR), and Green Near Infrared (GNIR). Statistical analysis was performed using SPSS and Microsoft Excel. The results consistently indicated a negative impact on the environment resulting from the oil spill. A comparison of spectral reflectance values between the oil spill site and the non-oil spill site showed lower values at the oil spill site across all vegetation indices (NDVI 0.0665-0.2622, ARVI –0.0495-0.1268, SAVI 0.0333-0.1311, GSWIR –0.183-0.0517, GNIR –0.0104-–0.1980), indicating damage to vegetation. Additionally, the study examined the correlation between vegetation indices and environmental parameters associated with the oil spill, revealing significant relationships with TPH, THC, and PAH. A t-test with a significance level of p &lt; 0.05 indicated significantly higher vegetation index values at the non-oil spill site compared to the oil spill site, suggesting a potential disparity in vegetation health between the two areas. Hence, this study emphasizes the harmful effect of oil spills on vegetation and highlights the importance of utilizing vegetation indices and spectral reflectance analysis to detect and monitor the impact of oil spills on vegetation.

River sediment microbial community composition and function impacted by thallium spill

Thallium (Tl) is widely used in various industries, which increases the risk of leakage into the environment. Since Tl is highly toxic, it can do a great harm to human health and ecosystem. In order to explore the response of freshwater sediment microorganisms to sudden Tl spill, metagenomic technique was used to elucidate the changes of microbial community composition and functional genes in river sediments. Tl pollution could have profound impacts on microbial community composition and function. Proteobacteria remained the dominance in contaminated szediments, indicating that it had a strong resistance to Tl contamination, and Cyanobacteria also showed a certain resistance. Tl pollution also had a certain screening effect on resistance genes and affected the abundance of resistance genes. Metal resistance genes (MRGs) and antibiotic resistance genes (ARGs) were enriched at the site near the spill site, where Tl concentration was relatively low among polluted sites. When Tl concentration was higher, the screening effect was not obvious and the resistance genes even became lower. Moreover, there was a significant correlation between MRGs and ARGs. In addition, co-occurrence network analysis showed that Sphingopyxis had the most links with resistance genes, indicating that it was the biggest potential host of resistance genes. This study provided new insight towards the shifts in the composition and function of microbial communities after sudden serious Tl contamination.

Anthropogenic petroleum signatures and biodegradation in subantarctic Macquarie Island soils

Special Antarctic Blend (SAB) diesel is the main fuel used on Macquarie Island and has been identified as the primary contaminant in several past spill events. This study evaluates the environmental impact of petroleum spills at high latitudes, in the soils of subantarctic Macquarie Island. Soil samples were collected from seven locations, including the “fuel farm” and main powerhouse that have been contaminated by petroleum in the past, and five reference locations, away from station infrastructure and from any obvious signs of contamination. Soils were solvent extracted and analysed using gas chromatography-mass spectrometry. The results show that both contaminated and uncontaminated sites contained a suite of different chain-length hydrocarbons. The more contaminated samples from the fuel farm and main powerhouse contained higher concentrations and a greater range of hydrocarbons that typically indicate numerous spills of varying ages. The hydrocarbon signature of samples collected near the fuel farm and at some of the main powerhouse sites was typical of SAB diesel. However, the hydrocarbon signature at other main powerhouse sites suggest contamination with a heavier fuel with different characteristics, including lower pristane/phytane ratios. Traces of C21–C35 cyclic biomarkers in the spill sites may be derived from additional heavier fuels, and include a signature characteristic of crude oil derived from marine carbonate source rocks. Reference samples had lower concentrations of hydrocarbons, and these were dominated by high molecular weight n-alkanes with an odd-carbon-number predominance, typical of higher-plant derived lipids. Some reference samples also contained geochemical signatures that suggest that they too were contaminated by fuel oil. Variable levels of biodegradation of fuels in soils are consistent with a heterogenous site and a relatively slow rate of biodegradation. The occurrence of fresh spilled fuel overprinting biodegraded fuel from earlier spills is compelling evidence of multiple spills and complex mixing in the environment.