Petroleum Hydrocarbon Contamination Research Articles

Risk assessment and biodegradation potential of PAHs originating from Map Ta Phut Industrial Estate, Rayong, Thailand

ABSTRACT Petroleum hydrocarbon contamination is a serious concern across the globe. Here, the capability of native bacterial consortium enriched from sediment samples of Map Ta Phut Industrial Estate (MTPIE), Rayong, Thailand was described. The distribution of PAHs was assessed from the sediment samples collected from MTPIE by GC-FID and the toxic unit (TU) was calculated to assess the potential ecological risk to the surrounding biota. This study investigated the degradation potential and determined the PAH-degrading bacterial cultures by enriching collected sediments in PAHs mixtures (naphthalene, phenanthrene, and pyrene). The TPH degradation capacity of each bacterial consortium was validated in a soil microcosm using aged crude oil-contaminated soil. The MTPIE sediments were highly contaminated with PAHs (843.99-3904.39 ng g-1) and posed extremely high ecological risks to benthic biota (TU > 1). The consortium S5-P most significantly removed naphthalene (90.03%) and phenanthrene (88.14%) while the highest removal of pyrene was achieved by the S3-P consortium. Other consortia only partially degraded the PAHs. The dominant microbes in the consortia were determined using PCR-DGGE, it was found that the PAH degrading consortia were known PAH degraders such as Annwoodia, Bacillus, Brevibacillus, Lysinibacillus, Paracoccus, Rhodococcus, Sphingopyxis, Sulfurovum, and Sulfurimonas species and unknown PAH degraders such as Lithuaxuella species. The consortium S5-P showed the highest degradation capacity, removing 74.99% of TPHs in the soil microcosm. Furthermore, the inoculation of PAH-biodegrading bacterial consortia significantly promoted the catechol-2,3-dioxygenase (C23O) and dehydrogenase (DHA) activities which directly correlated with the degradation efficiency of petroleum hydrocarbons (p < 0.05).

Evaluation of Simulated Petroleum Hydrocarbon on the Physicochemical Properties of Soil

Petroleum hydrocarbon contamination of soils has become a global concern, which is often caused by anthropogenic activities, posing serious threat to all living beings. The study for evaluation of the variability of crude oil on the physicochemical characteristics of sandy loam soil was conducted at demonstration farm, Rivers state university, Port-Harcourt, Nigeria. The Bonny light crude oil was obtained from an oil and gas production company. Uncontaminated soil was mixed with crude oil. Standard procedures were adopted for the laboratory analysis, the parameters analyzed include bulk density, total porosity, pH, available phosphorus (P), Total hydrocarbon content (THC), organic carbon, organic matter, exchangeable cation (Mg, K, Na, Ca), effective cation exchange capacity (ECEC), total exchangeable acidity (TEA), and base saturation were monitored for a period of 21 days. 10 kg of sandy loam soils were mixed with 100, 300, 500, and 700ml of crude oil while no crude oil serves as the control using plastic reactors. The reactor with 700ml of crude oil recorded the highest THC of 1734.33 mg/kg, followed by 500ml with a THC of 1601mg/kg while the control with no contamination recorded the least THC of 534.33mg/kg. However, the values of all concentrations did not meet 5000 mg/kg of Department of Petroleum Resources (2018) intervention value but exceeded the target value of 50 mg/kg. Other parameters followed same trend except porosity which decreased with increase in crude oil volume. There were significant differences at P&lt; 0.05 except for pH, available P, and base saturation. Therefore, this study calls for the utilization of its findings for adoption of remediation on crude oil contaminated soils.

Bioremediation Treatment of Polyaromatic Hydrocarbons for Environmental Sustainability

Polycyclic aromatic hydrocarbons (PAHs) distributed in air and soil are harmful because of their carcinogenicity, mutagenicity, and teratogenicity. Biodegradation is an environmentally friendly and economical approach to control these types of contaminants and has become an essential method for remediating environments contaminated with petroleum hydrocarbons. The bacteria are isolated and identified using a mineral nutrient medium containing PAHs as the sole source of carbon and energy and biochemical differential tests. Thus, this study focuses on some bacteria and fungi that degrade oil and hydrocarbons. This study provides a comprehensive, up-to-date, and efficient overview of petroleum hydrocarbon contaminant bioremediation considering hydrocarbon modification by microorganisms, emphasizing the new knowledge gained in recent years. The study shows that petroleum hydrocarbon contaminants are acceptably biodegradable by some microorganisms, and their removal by this method is cost-effective. Moreover, microbial biodegradation of petroleum hydrocarbon contaminants utilizes the enzymatic catalytic activities of microorganisms and increases the degradation of pollutants several times compared to conventional methods. Biological treatment is carried out in two ways: microbial stimulation and microbial propagation. In the first method, the growth of indigenous microorganisms in the area increases, and the pollution is eliminated. In the second method, on the other hand, there are no effective microorganisms in the area, so these microorganisms are added to the environment.

Microbial Bioremediation and Biodegradation of Petroleum Products—A Mini Review

The demand for technological and industrial change has become heavily dependent on the availability and use of petroleum products as a source of energy for socio-economic development. Notwithstanding, petroleum and petrochemical products are strongly related to global economic activities, and their extensive distribution, refining processes, and final routes into the environment pose a threat to human health and the ecosystem. Additional global environmental challenges related to the toxicological impact of air, soil, and water pollutants from hydrocarbons are carcinogenic to animals and humans. Therefore, it is practical to introduce biodegradation as a biological catalyst to address the remediation of petroleum-contaminated ecosystems, adverse impacts, the complexity of hydrocarbons, and resistance to biodegradation. This review presents the bioremediation of petroleum hydrocarbon contaminants in water and soil, focusing on petroleum biodegradable microorganisms essential for the biodegradation of petroleum contaminants. Moreover, explore the mineralization and transformation of complex organic and inorganic contaminants into other simpler compounds by biological agents. In addition, physicochemical and biological factors affecting biodegradation mechanisms and enzymatic systems are expanded. Finally, recent studies on bioremediation techniques with economic prospects for petroleum spill remediation are highlighted.

Bioelectrochemical Remediation for the Removal of Petroleum Hydrocarbon Contaminants in Soil

Consistent accumulation of petroleum hydrocarbon (PH) in soil and sediments is a big concern and, thus, warrants a static technology to continuously remediate PH-contaminated soil. Bioelectrochemical systems (BESs) can offer the desired solution using the inimitable metabolic response of electroactive microbes without involving a physiochemical process. To date, a wide range of BES-based applications for PH bioremediations under different environmental conditions is readily available in the literature. Here, the latest development trend in BESs for PH bioremediation is critically analyzed and discussed. The reactor design and operational factors that affect the performance of BESs and their strategic manipulations such as designing novel reactors to improve anodic reactions, enhancing soil physiology (electrical conductivity, mass diffusion, hydraulic conductivity), electrode modifications, operational conditions, microbial communities, etc., are elaborated to fortify the understanding of this technology for future research. Most of the literature noticed that a low mass diffusion condition in soil restricts the microbes from interacting with the contaminant farther to the electrodes. Therefore, more research efforts are warranted, mainly to optimize soil parameters by specific amendments, electrode modifications, optimizing experimental parameters, integrating different technologies, and conducting life cycle and life cycle cost analysis to make this technology viable for field-scale applications.

Patterns of groundwater bacterial communities along the petroleum hydrocarbon gradient

Groundwater contamination by petroleum hydrocarbons has become a worldwide environmental problem. Despite that microorganisms played an important role in biogeochemical processes such as hydrocarbon degradation, comprehensive understanding of the structure, function, and interactions of groundwater bacterial communities in petroleum hydrocarbon-contaminated sites is still lacking. Here we investigated the groundwater bacterial communities along a total petroleum hydrocarbon gradient (TPH: 0.01–2.09 mg/L) at an abandoned chemical factory site by sequencing microbial 16 S rRNA gene amplicons. Results showed that hydrocarbon contamination in groundwater reduced the bacterial diversity, and favored the growth of some species, such as members of the β-, γ-Proteobacteria and Planctomycetes. TPH exerted profound selection pressure on the bacterial community, as the variation of community structure along the TPH gradient were significantly correlated with the petroleum hydrocarbon tolerance of the community (r = 0.362; p < 0.001). Other geochemical variables of the groundwater, including pH, sampling depth, oxidation-reduction potential, temperature, and dissolved oxygen, also influenced the community structure. Variations in bacterial community structure thus altered the functional potential, with significantly higher alkane (alkB and alkH) and PAH (nahF and phdK) degradation gene abundances in the relatively high contaminated sampling wells. By conducting the ecological network analysis, we identified a potentially important ecological module relating to petroleum hydrocarbon degradation, which is mainly composed of members of Proteobacteria. This suggested the potential metabolic cross-feeding relationship of Proteobacteria in utilizing petroleum hydrocarbon. These findings illustrate an overall picture of bacterial communities involved in a petroleum hydrocarbon contamination site and provided useful information for groundwater restoration and environmental management.

Hydrocarbon Degradation Potentials of Fungi: A Review

One of the serious problems affecting the environment nowadays is petroleum hydrocarbon contaminations resulting from the activities in the oil and gas sector, these include: oil-spill, tank leakage, lubrication, petroleum exploitation, transportation, and services. Various techniques including mechanical and chemical methods have been employed for the bioremediation and degradation of hydrocarbons pollutants from the environments, however, some of these methods are generally expensive and may have detrimental effects on the environment, hence bioremediation is the alternative solution to hydrocarbon pollutants. Among microorganisms used in bioremediation technology nowadays, fungi are efficient, reliable, cost-effective, and environmentally friendly that can be used to cleanup and detoxify hydrocarbons contaminants from the environment viz; soil, water, and sediments. Bioremediation using fungi ensures the complete degradation and mineralization of petroleum hydrocarbon contaminants into carbon dioxide, water, inorganic compounds, and cell biomass. This review focuses on the potentials of fungi in the bioremediation of total petroleum hydrocarbons including the polycyclic aromatic hydrocarbons (PAHs). We reviewed and discussed current approaches in the bioremediation of hydrocarbon including the mechanisms of fungal bioremediation of hydrocarbon, which involves biosurfactants production and the use of fungal enzymes in the degradation of hydrocarbon pollutants. In general, fungi are more efficient and effective in the removal of hydrocarbon contaminants from the environments viz., water, soil, and sediments. However, the potentiality of fungi has not been exploited fully, hence further studies are recommended especially in the current genomic and proteomic era.

Converging alfalfa (Medicago sativa L.) and petroleum hydrocarbon acclimated ACC-deaminase containing bacteria for phytoremediation of petroleum hydrocarbon contaminated soil

Plant assisted bioremediation of petroleum hydrocarbon contaminated soil is considered an effective green technology whereby accelerated degradation occurs due to converged effect of microorganisms and plants. However, survival and growth of microbes and plants under stress conditions is challenging task for success of the technology. In this study, plant growth promoting bacteria containing 1-aminocyclopropane-1-carboxylate (ACC)-deaminase activity and tolerance to petroleum hydrocarbon contamination were used in association with alfalfa for bioremediation of petroleum hydrocarbon contaminated soil. Eight pre-isolated bacterial isolates from soil having previous history of petroleum contamination were used in convergence with alfalfa on sand soil which was artificially contaminated (10 g crude oil per kg−1 of coarse textured soil). Combined effect of bacteria and plants on the degradation of petroleum hydrocarbons under controlled conditions of light and temperature was observed for a period of 60 days. The results of the study revealed that four bacterial isolates Bacillus subtilis strain PM32Y, Bacillus cereus strain WZ3S1, Bacillus sp. strain SM73 and Bacillus sp. strain WZ3S3 in association with alfalfa significantly degraded petroleum hydrocarbons. The most significant biodegradation (47%) of petroleum hydrocarbons was recorded in the experimental unit receiving PM32Y inoculation in association with alfalfa. Biodegradation of petroleum hydrocarbons was 33% with alone inoculation (without alfalfa) of PM32Y. The study revealed that combined use of bacteria and alfalfa plant is more efficient than alone application of either bacteria or plants for degradation of petroleum hydrocarbons.

Response of soil microbial communities to petroleum hydrocarbons at a multi-contaminated industrial site in Lanzhou, China

Total petroleum hydrocarbon (TPH) contamination poses threats to ecological systems and human health. Many studies have reported its negative impacts on soil microbes, but limited information is known about microbial change and response to multiple TPH contamination events. In this study, we investigated TPH contamination level, microbial community structure and functional genes at a multi-contaminated industrial site in Lanzhou, where a benzene spill accident caused the drinking water crisis in 2014. TPHs distribution in soils and groundwater indicated multiple TPH contamination events in history, and identified the spill location where high TPH level (6549 mg kg−1) and high ratio of low-molecular-weight TPHs (>80%) were observed. In contrast, TPH level was moderate (349 mg kg−1) and the proportion of low-molecular-weight TPHs was 44% in soils with a long TPH contamination history. After the spill accident, soil bacterial communities became significant diverse (p = 0.047), but the dominant microbes remained the same as Pseudomonadaceae and Comamonadaceae. The abundance of hydrocarbon-degradation related genes increased by 10–1000 folds at the site where the spill accident occurred in multi-contaminated areas and was significantly related to 2-ring PAHs. Such changes of microbial community and hydrocarbon-degradation related genes together indicated the resilience of soil indigenous microbes toward multiple contamination events. Our results proved the significant change of bacterial community and huge shift of hydrocarbon-degradation related genes after the spill accident (multiple contamination events), and provided a deep insight into microbial response at industrial sites with a long period of contamination history.

Assessment of Total Petroleum Hydrocarbon Contamination of the Red Sea with Endemic Fish from Jeddah (Saudi Arabia) as Bioindicator of Aquatic Environmental Pollution

The aim of this study was to determine whether endemic coral fish commonly consumed by Jeddah residents could serve as bioindicators of oil contamination. In addition, we planned to investigate the relationship between amino acid changes and hydrocarbon concentrations in fish tissue. The composition of amino acids was analyzed using high-pressure liquid chromatography with precolumn derivatization. An analytical study of the polycyclic aromatic hydrocarbons and total petroleum hydrocarbons was conducted by combining gas chromatography with gas chromatography/mass spectrometry. Multivariate statistical analysis was applied using Statgraphics software to determine the impact of the polycyclic aromatic hydrocarbons and total petroleum hydrocarbons on the amino acid profile of three species of fish. In addition, the bioconcentration factor was estimated in the studied species and was used to validate the results obtained from the multivariate analysis. Based on the results of the study, the sum of polycyclic aromatic hydrocarbons with two cycles, and with five to six cycles, is in reverse order in Plectropomus pessuliferus with respect to Epinephelus tauvina and Cephalopholis argus. The factor analysis showed high factor scores for aspartic acid, glutamic acid, tyrosine, chrysene, and total petroleum hydrocarbons, and for lipids and benzo(g,h,i)perylene, which could be explained by bioaccumulation. It was concluded that the high proportions of glutamic acid (8.32–11.10%) and aspartic acid (6.06–8.27%) in the muscles of the studied species are a sign of contamination with petroleum hydrocarbons. The incremental lifetime cancer risk values for the three endemic fish exceeded the limit value (&gt;10−5), indicating a high potential cancer risk for the Saudi population.

Interaction and spatio-taxonomic patterns of the soil microbiome around oil production wells impacted by petroleum hydrocarbons

Numerous onshore oil production wells currently exist, and the petroleum hydrocarbon contamination of the surrounding soil caused by oil production wells is not well understood. Moreover, the impact of the distribution of the total petroleum hydrocarbons (TPH) in the soil on the microbiota requires further investigation. Accordingly, in this study, the distribution of petroleum hydrocarbons in the soils around oil production wells was investigated, and their alteration of the microbiota was revealed. The results revealed that in the horizontal direction, the heavily TPH-contaminated soils were mainly distributed within a circle with a radius of 200 cm centered on the oil production well; and in the vertical direction, the heavily TPH-contaminated soils were distributed within the 0–50 cm soil layer. A significant positive correlation was found between the microbial abundance and the TPH concentration in the soil with relatively low total carbon contents. Heavy TPH contamination (TPH concentration of >3000 mg/kg) significantly reduced the microbial diversity and altered the microbiota compared with the light TPH contamination (TPH concentration of around 1000 mg/kg). In the heavily TPH-contaminated soils, the relative abundances of the Proteobacteria and Bacteroides increased significantly; the network complexity among the soil microorganisms decreased; and the co-occurrence patterns were altered. In summary, the results of this study have reference value in the remediation of soils around oil production wells and provide guidance for the construction of microbial remediation systems for petroleum contamination.

Enhanced oil removal from oily sand by injecting micro-macrobubbles in swirl elution

Environmental contamination by petroleum hydrocarbons was exacerbated by oil pipeline breaks, marine oil spills and discharges from industrial production. To further improve the removal performance of petroleum hydrocarbons in solid particles, the deoiling experiments of swirl elution with micro-macrobubbles on oily sands were carried out in this paper. Experiment results indicated that when particles fell from the center of the bubble, the collision efficiency was 99.3%. The instantaneous contact angle (ICA) between the macrobubbles and the oil layer was improved in the presence of microbubbles. Furthermore, the maximum ICA of bubbles attaching to the oil layer was found to occur at pH 9 in the system of oily sand mixtures ranging from pH 5 to pH 14. This finding indicated that the slightly alkaline solution was more advantageous for bubbles to attach to the oil layer than the highly alkaline solution. The optimum condition for the elution of oily sand in the mixture of pH 7–14 was pH 12, and the oil removal efficiency was 85.4% for 10 min. The oil removal efficiency of swirl elution (SE) with bubbles on oily sand at pH 12 for 10 min was superior to either SE without bubbles or air flotation (AF). The results show that the swirl elution with bubbles can effectively enhance the oil removal efficiency of oily sands and provide guidance for controlling the environmental petroleum hydrocarbon contamination and reducing the usage of surfactants.

Bioremediation of Petroleum Contamination: A Short Review

The pros and cons of using the bioremediation method for the removal of petroleum pollutants are discussed in this review article. Other methods along with bioremediation have been used to remediate petroleum hydrocarbon contaminants in the past. Bioremediation is cheap and efficient method than any other because major constituents of the crude oils are biodegradable. Despite the fact that, as compared to physicochemical strategies, longer periods are normally required, complete pollutant degradation can be achieved, and no further containment of the contaminated matrix is required. According to hydrocarbon present in the contaminants different strategies and organism are used for the bioremediation.&#x0D; Common strategies include controlling environmental factors such as oxygen availability, hydrocarbon solubility, nutrient balance and managing hydrocarbon degrading bacteria by eliminating the rate limiting factors that may slow down the bioremediation rate. Microorganism dynamics during bioremediation is most important for understanding how they respond, adapt and remediate pollution. However, bioremediation can be considered one of the best technologies to deal with petroleum product contaminants.

Prospects in the bioremediation of petroleum hydrocarbon contaminants from hypersaline environments: A review.

Hypersaline environments are underappreciated and are frequently exposed to pollution from petroleum hydrocarbons. Unlike other environs, the high salinity conditions present are a deterrent to various remediation techniques. There is also production of hypersaline waters from oil-polluted ecosystems which contain toxic hydrophobic pollutants that are threat to public health, environmental protection, and sustainability. Currently, innovative advances are being proposed for the remediation of oil-contaminated hypersaline regions. Such advancements include the exploration and stimulation of native microbial communities capable of utilizing and degrading petroleum hydrocarbons. However, prevailing salinity in these environments is unfavourable for the growth of non-halophylic microorganisms, thus limiting effective bioremediation options. An in-depth understanding of the potentials of various remediation technologies of hydrocarbon-polluted hypersaline environments is lacking. Thus, we present an overview of petroleum hydrocarbon pollution in hypersaline ecosystems and discuss the challenges and prospects associated with several technologies that may be employed in remediation of hydrocarbon pollution in the presence of delimiting high salinities. The application of biological remediation technologies including the utilization of halophilic and halotolerant microorganisms is also discussed.

Kinetic modelling of in situ treatment of petroleum hydrocarbon contaminated soil using bone char and NPK fertilizers

This study investigates the effectiveness of bone char (organic) and inorganic nitrogen, phosphorous, and potassium (NPK) fertilizers as stimulants in the degradability of petroleum hydrocarbon contaminants on soil. The physicochemical properties of the hydrocarbon sludge were used to assess the effectiveness of this process over an 8-week period using 0.5–3.5 kg mass of each fertilizer at different experiments. A first order kinetic model was used to estimate the rate of degradation of the total hydrocarbon content (THC) and total organic carbon (TOC) contaminants and the half-life of the remediation process. The microbial population within the period was also determined. The p-value (p < 0.05) indicated that these fertilizers were effective in degrading these contaminants on the soil, because of the significant difference between the treated and the control soil samples. A direct relationship was observed between with the mass and performance of the fertilizers. With 3.5 kg mass of the fertilizers, rate constants of 0.018 and 0.019 d− 1 were obtained for the removal of the THC and TOC contaminants, respectively, using the bone char fertilizer, whereas NPK fertilizer gave rates of 0.03 and 0.023 d− 1 respectively. The performance of the NPK fertilizer is attributable to its nitrogen and phosphorous content. The model adequately described the process and showed the effectiveness of both fertilizers in the remediation process.

Characteristics of the Archaeal Communities in Petroleum Hydrocarbon-Contaminated Groundwater

Characteristics of the Archaeal Communities in Petroleum Hydrocarbon-Contaminated Groundwater

The role of predicted chemotactic and hydrocarbon degrading taxa in natural source zone depletion at a legacy petroleum hydrocarbon site

Petroleum hydrocarbon contamination is a global problem which can cause long-term environmental damage and impacts water security. Natural source zone depletion (NSZD) is the natural degradation of such contaminants. Chemotaxis is an aspect of NSZD which is not fully understood, but one that grants microorganisms the ability to alter their motion in response to a chemical concentration gradient potentially enhancing petroleum NSZD mass removal rates. This study investigates the distribution of potentially chemotactic and hydrocarbon degrading microbes (CD) across the water table of a legacy petroleum hydrocarbon site near Perth, Western Australia in areas impacted by crude oil, diesel and jet fuel. Core samples were recovered and analysed for hydrocarbon contamination using gas chromatography. Predictive metagenomic profiling was undertaken to infer functionality using a combination of 16 S rRNA sequencing and PICRUSt2 analysis. Naphthalene contamination was found to significantly increase the occurrence of potential CD microbes, including members of the Comamonadaceae and Geobacteraceae families, which may enhance NSZD. Further work to explore and define this link is important for reliable estimation of biodegradation of petroleum hydrocarbon fuels. Furthermore, the outcomes suggest that the chemotactic parameter within existing NSZD models should be reviewed to accommodate CD accumulation in areas of naphthalene contamination, thereby providing a more accurate quantification of risk from petroleum impacts in subsurface environments, and the scale of risk mitigation due to NSZD.

Mature petroleum hydrocarbons contamination in surface and subsurface waters of Kızılırmak Graben (Central Anatolia, Turkey): Geochemical evidence for a working petroleum system associated with a possible salt diapir

Salt formations exist in Kızılırmak Graben (Central Anatolia, Turkey), which consists of volcano-sedimentary units, and it was stated in previous studies that these formations have a diapiric structure. The adjacent basin, Ayhan Basin, contains bituminous shale and operated coal deposits. For this reason, in this study, it is aimed to investigate the oil and gas potential of the Kızılırmak Graben by conducting TPH (Total Petroleum Hydrocarbons) analysis on the samples taken from natural cold-water resources by making use of the thought that hydrocarbon generation may come into existence from those units in the Ayhan basin. As a consequence of the analyses performed, hydrocarbons have been brought into the open in all the water samples. The organic geochemical methods have been used to find out the source of hydrocarbons determined in the water resources. The disclosed n-alkane hydrocarbons are the mature petroleum hydrocarbons derived from peat/coal type organic matter (Type III kerogen, gas-prone). These mature hydrocarbon-rich waters can be regarded as evidence for the availability of a working hydrocarbon system associated with possible salt diapir identified by using gravity and magnetic data obtained from the investigation area.

A Review of the Petroleum Hydrocarbons Contamination of Soil, Water and Air and the Available Remediation Techniques, Taking into Consideration the Sustainable Development Goals

The emergence of several industrial activities has arguably led to hydrocarbon contamination of all aspects of the environment. The resultant effect of the increased dependence on crude oil is the hydrocarbon pollution via the exploration, transport and waste disposal. Crude oil is a complex mixture of aliphatic, aromatic and heterocyclic compounds. The impact of the crude oil spills, pesticides, fossil fuels and other organic pollutants, which majorly contains these hydrocarbons is that the natural heavy metal content of the soil is drastically rising, resulting in high concentration of heavy metals, thereby limiting the microbe’s activity, rendering it unsuitable for degradation and reduced effectiveness. This menace has hereby brought the dire need for adequate environmental remediation technique, putting into consideration the achievement of the Sustainable Development Goals (SDGs’). Variety of techniques exist for remediation depending on the media (e.g. air, water, or soil) and contaminant (e.g. heavy metals, PCB etc.). Some of the techniques adopted in the last several decades are physical/mechanical, chemical or biochemical remediation methods.

ОЦЕНКА ФЕРМЕНТАТИВНОЙ АКТИВНОСТИ НЕФТЕЗАГРЯЗНЕННОГО ЧЕРНОЗЕМА ПОСЛЕ БИОРЕМЕДИАЦИИ

Introduction. The evaluation of the ecological state of soils in terms of enzymatic activity during the remediation of petroleum hydrocarbons contamination is very informative. The activity of enzymes of the oxidoreductases and hydrolases classes in chernozem is most sensitive to contamination by heavy metals, pesticides, and other types of anthropogenic impact. The informativeness and sensitivity of enzymes during the remediation of petroleum hydrocarbons-contaminated soils have not been adequately studied. Materials and methods. The activity of seven enzymes of oxidoreductases and hydrolases classes of petroleum hydrocarbons-contaminated soils after the application of biochar, sodium humate, nitroammophos and Baikal EM-1 was studied. In 90 days from the moment the ameliorants were introduced into the soil, the enzymatic activity of soils was evaluated by changes in the activity of catalase, dehydrogenases, peroxidases, ferrireductases, invertase, urease, and phosphatases. The integral indicator of soil biological activity (IIBA) and the geometric mean enzymatic activity of soils were evaluated for the classes of oxidoreductases (GMea (ОХ)) and hydrolases (GMea (HD)). Results. During the remediation of petroleum hydrocarbons-contaminated chernozem, the concentration of D0.5 of biochar and Baikal EM-1 has a stimulating effect on the activity of oxidoreductases and hydrolases of the soil, and D2 of nitroammophos and sodium humate – D2. At a dose of D0.5 of nitroammophos and biochar, the maximum stimulation of IIBA was established relative to control and petroleum hydrocarbons contamination. The introduction of nitroammophos stimulated the activity of three out of seven enzymes, and biochar stimulated the activity of five out of seven enzymes regarding petroleum hydrocarbons contamination. The highest efficiency of nitroammophos is largely due to excessive stimulation of the urease activity of ordinary chernozem. The values of the geometric mean enzymatic activity (GMea) of oxidoreductases and hydrolases were stimulated relative to the control at a dose of D0.5 of each ameliorant. The sensitivity series of petroleum hydrocarbons-contaminated chernozem enzymes after the introduction of ameliorants from the most sensitive to the least sensitive is the following: ferrireductases &gt; peroxidases &gt; urease &gt; phosphatase &gt; dehydrogenases &gt; invertase &gt; catalase. According to the degree of restoration of the enzymatic activity of soils, the ameliorants can be arranged in the following order (in % of petroleum hydrocarbons contamination): nitroammophos &gt; biochar &gt; sodium humate &gt; Baikal EM-1. Conclusion. During the remediation of petroleum hydrocarbons-contaminated chernozem, the most stimulating effect on the activity of oxidoreductases and soil hydrolases is exerted by the ameliorant at a concentration of D0.5. For biodiagnostics of the ecological state of petroleum hydrocarbons-contaminated black soils, we recommend using the activity of ferrireductases, peroxidases, urease, and phosphatase.