Coalescence of multiple droplets induced by a constant DC electric field.

In this work, the electro-coalescence process of three nanodroplets under a constant DC electric field is investigated via molecular dynamics simulations (MD), aiming to explore the electric manipulation of multiple droplets coalescence on the molecular level. The symmetrical and asymmetrical dynamic evolutions of electrocoalescence process can be observed. Our MD simulations show that there are two types of critical electric fields to induce the special dynamics. The chain configuration can be formed, when one of the critical electric field is exceeded, referred to as Ecc. On the other hand, there is another critical electric field to change the coalescence pattern from complete coalescence to partial coalescence, the so-called Ecn. Finally, we find that the use of the pulsed DC electric field can overcome the drawbacks of the constant DC electric field in the crude oil industry, and the mechanisms behind the suppressed effect of the water chain or non-coalescence are further revealed.

[Aftershocks; about the psychological consequences of gas extraction in Groningen]. / Naschokken; over de psychische gevolgen van de gaswinning in Groningen.

BACKGROUND: In recent decades, gas extraction in Groningen has led to a lot of material and immaterial damage, including much psychological suffering, which was ignored by policymakers for years. With the publication of the report of the Parliamentary Inquiry into Natural Gas Extraction in Groningen, this is recognized and suggestions are made to repair the damage caused in the broadest sense. AIM: Description of current and expected psychological consequences, and research and treatment to be conducted focused on this specific regional phenomenon. METHOD: Describing the Groningen situation based on various sources, and identifying current and expected mental consequences based on currently available data and scientific literature. RESULTS: Psychological consequences are largely known and identified, but not yet quantified. It is most important for the well-being of inhabitants that the government takes its care task seriously and supports victims in a practical sense. Subsequently, a targeted treatment offer must be developed. CONCLUSION: The knowledge available within psychiatry and psychology about the development and treatment of psychological complaints should play a role in researching and improving the well-being and the mental health of those affected by the gas extraction problem, now and in the future.

Simultaneous removal of crude oil and heavy metals by highly adapted bacterial strain Cutibacterium sp. NL2 isolated from Algerian oilfield

Investigating the ability of bacteria to simultaneously enhance hydrocarbon removal and reduce heavy metals’ toxicity is necessary to design more effective bioremediation strategies. A bacterium (NL2 strain) isolated from an Algerian oilfield was cultivated on crude oil as sole carbon and energy sources. Molecular analyses of the 16S rRNA gene sequence placed the strain within the Cutibacterium genera. This isolate was able to tolerate up to 60% of crude oil as sole carbon source. Chemical analyses (GC-MS) evidenced that strain NL2 was able to degrade 92.22% of crude oil (at optimal growing conditions: pH 10, 44 °C, 50 g L−1 NaCl, and 20% of crude oil (v/v) as sole carbon source) in only 7 days. NL2 isolate was also able to produce biosurfactants with reduction of surface tension of growing media (29.4 mN m−1). On the other hand, NL2 strain was able to tolerate high lead (Pb) and copper (Cu) concentrations (up to 60 mM). In fact, NL2 cultivated in the presence of 20% of crude oil, and 0.48 mM of Pb was able to reduce Pb concentration by a 41.36%. In turn, when cultivated on high Pb concentration (15 mM), the strain was able to remove 35.19% of it and 86.25% of crude oil, both in a time frame of 7 days. Our findings suggest that Cutibacterium strain NL2 is able to efficiently use and remove a wide range of crude oil substrates in presence of high Pb concentration. Accordingly, NL2 strain is of extreme interest from a biotechnological standpoint. (AU)

Multivariate analysis of carcinogenic equivalence (CEQ) to characterize carcinogenic VOC emissions in a typical petrochemical industrial park in Taiwan.

Large industrial emissions of volatile organic compounds (VOCs) from the petrochemical industry are a critical concern due to their potential carcinogenicity. VOC emissions vary in composition depending on the source and occur in mixtures containing compounds with varying degrees of toxicity. We proposed the use of carcinogenic equivalence (CEQ) and multivariate analysis to identify the major contributors to the carcinogenicity of VOC emissions. This method weights the carcinogenicity of each VOC by using a ratio of its cancer slope factor to that of benzene, providing a carcinogenic equivalence factor (CEF) for each VOC. We strategically selected a petrochemical industrial park in southern Taiwan that embodies the industry's comprehensive nature and serves as a representative example. The CEQs of different emission sources in three years were analyzed and assessed using principal component analysis (PCA) to characterize the major contributing sectors, vendors, sources, and species for the carcinogenicity of VOC emissions. Results showed that while the study site exhibited a 20.7 % (259.8 t) decrease in total VOC emissions in three years, the total CEQ emission only decreased by 4.5 % (15.9 t), highlighting a potential shift in the emitted VOC composition towards more carcinogenic compounds. By calculating CEQ followed by PCA, the important carcinogenic VOC emission sources and key compounds were identified. More importantly, the study compared three approaches: CEQ followed by PCA, PCA followed by CEQ, and PCA only. While the latter two methods prioritized sources based on emission quantities, potentially overlooking less abundant but highly carcinogenic compounds, the CEQ-first approach effectively identified vendors and sources with the most concerning cancer risks. This distinction underscores the importance of selecting the appropriate analysis method based on the desired focus. Our study highlighted how prioritizing CEQ within the analysis framework empowered the development of precise control measures that address the most carcinogenic VOC sources.

Levels and control of welding fume exposure to total particulate, hexavalent chromium, and manganese in contracted activities in an oil refinery setting (2008-2018).

In response to increasing focus on occupational exposures to welding fume, a 10-year series of personal exposure measurements was analyzed for the two main welding processes (Shielded Metal Arc Welding or Stick and Tungsten Inert Gas welding or TIG) used in an oil refinery setting. Exposures from ancillary gouging and grinding were also analyzed. The operations were conducted under a permit-to-work system, which stipulated control measures in the form of ventilation and respiratory protective equipment (RPE) depending on the work environment, base metal, and welding process. The analysis focused on three health hazards of interest: total particulate (TP); hexavalent chromium (Cr (VI)); and manganese (Mn). The study's aims were the analysis of exposure levels related to operational conditions to verify the adequacy of required control measures and the generation of quantitative information for the development of predictive exposure models. Arithmetic mean exposures were 2.01 mg/m3 for TP (n = 94), 13.86 µg/m3 for Cr (VI) (n = 160), and 0.024 mg/m3 for Mn (n = 95). Requirements and practices for ventilation and use of RPE appeared adequate for maintaining exposure levels below maximum use concentrations. Predictive models for mean exposure levels were developed using multiple linear regression. Different patterns emerged for TP, Cr (VI), and Mn exposure determinants. Enclosed or confined work environments were associated with elevated exposure levels, regardless of the provision of local exhaust or general dilution ventilation. Carbon arc, used with gouging and grinding, contributed significantly to TP exposure (p = 0.006). The relative TP source strengths of the two main welding processes were comparable to the literature data. For Cr (VI), stick welding was associated with approximately 50-fold (p < 0.001) higher exposure potential than TIG welding. For Mn, this difference was approximately 2.5-fold. Differences were observed across the three analytes in exposure reduction efficiency of local exhaust ventilation (LEV) compared to natural ventilation, possibly due to ineffective use in confined spaces. These findings contribute to the overall understanding of TP, Cr (VI), and Mn exposures from welding and required controls in an oil refinery setting.

Framework for the assessment of the safety culture in the oil and gas industry.

Approaches to safety culture assessment may have many limits if supported exclusively by quantitative methods. Based on this, a research team developed a quantitative-qualitative approach to assess the maturity of the safety culture on an oil platform. To that end, the team sought to develop and test a method consisting of an initial ethnographic phase followed by four other distinct phases: definition of homogeneous groups; production of customized questionnaires; quantitative evaluation; and qualitative assessment. The results show the emergence of trends, from pre-defined themes in safety culture to specific levels of maturity for each of the homogeneous groups. At the same time, it was perceived that the maturity level of the groups is defined from the daily work practices developed by each one of them. This experience allowed us to propose a framework for assessing the maturity levels of safety culture for the oil and gas industry.

Is residential exposure to oil refineries a novel contextual risk factor for coronary heart disease?

Despite a multi-decade decrease in cardiovascular disease, geographic disparities have widened, with excess mortality concentrated within the United States (U.S.) South. Petroleum production and refining, a major contributor to climate change, is concentrated within the U.S. South and emits multiple classes of atherogenic pollutants. We investigated whether residential exposure to oil refineries could explain variation in self-reported coronary heart disease (CHD) prevalence among adults in southern states for the year 2018, where the majority of oil refinery activity occurs (Alabama, Mississippi, Louisiana, Arkansas, Texas, New Mexico, and Oklahoma). We examined census tract-level association between oil refineries and CHD prevalence. We used a double matching method to adjust for measured and unmeasured spatial confounders: one-to-n distance matching and one-to-one generalized propensity score matching. Exposure metrics were constructed based on proximity to refineries, activities of refineries, and wind speed/direction. For all census tracts within 10 km of refineries, self-reported CHD prevalence ranged from 1.2% to 17.6%. Compared to census tracts located at ≥5 km and <10 km, one standard deviation increase in the exposure within 5 km of refineries was associated with a 0.33 (95% confidence interval: 0.04, 0.63) percentage point increase in the prevalence. A total of 1119.0 (123.5, 2114.2) prevalent cases or 1.6% (0.2, 3.1) of CHD prevalence in areas within 5 km from refineries were potentially explained by exposure to oil refineries. At the census tract-level, the prevalence of CHD explained by exposure to oil refineries ranged from 0.02% (0.00, 0.05) to 47.4% (5.2, 89.5). Thus, although we cannot rule out potential confounding by other personal risk factors, CHD prevalence was found to be higher in populations living nearer to oil refineries, which may suggest that exposure to oil refineries can increase CHD risk, warranting further investigation.

Characterization and treatment of oily sludge: A systematic review.

Oily sludge is a prevalent hazardous waste generated in the petroleum industry, and effectively treating it remains a key challenge for the petroleum and petrochemical sectors. This paper provides an introduction to the origin, properties, and hazards of oil sludge while summarizing various treatment methods focused on reduction, recycling, and harmlessness. These methods include combustion, stabilization/solidification, oxidation and biodegradation techniques, solvent extraction, centrifugation, surfactant-enhanced oil recovery processes as well as freezing-thawing procedures. Additionally discussed are pyrolysis, microwave radiation applications along with electrokinetic method utilization for oily sludge treatment. Furthermore explored are ultrasonic radiation techniques and froth flotation approaches. These technologies have been thoroughly examined through discussions that analyze their process principles while considering influencing factors as well as advantages and disadvantages associated with each method. Based on the characteristics of oily sludge properties and treatment requirements, a selection methodology for choosing appropriate oily sludge treatment technology is proposed in this study. The development direction of processing technology has also been explored to provide guidance aimed at improving efficiency by optimizing existing processing technologies. The paper presents a comprehensive treatment method for oily sludge, ensuring that all the parameters meet the standard requirements.

An examination of the Petroleum Industry Act 2021: prospects, challenges, and the way forward.

Background: The study examines the gaps in the provisions of the Petroleum Industry Act (PIA) that could hinder the effective application of the Act in attaining its objectives. The repealed Petroleum Act of 1969 became obsolete and largely incapable of meeting the emerging global best practices in the industry due to inadequate sanctions, failure to address the aspirations of the people of the oil-bearing states, among others. Hence, the need for the PIA of 2021 to overhaul the industry to meet global standards though some controversial provisions that pose challenges to its proper implementation. Methods: The study examines the PIA to identify its prospects, challenges, and the way forward. The methodology the study utilises is doctrinal research with reports from existing literature and tertiary data sources such as newspapers, the Internet, and websites. Pertinent data collected from these sources were theoretically analysed and argued with current literature on the subject. Results: The finding is that the PIA does not make adequate provisions for the energy transition in line with Nigeria's Nationally Determined Contributions (NDC) under the Paris agreement; the PIA was provided for weak institutions, which translates to weak implementation and enforcement of the law which further widening the gap between the law and reality. Conclusions: The study concluded that, although the Act delivered the much-needed stability in the petroleum industry in Nigeria, there is a need for an overhaul of the Act to further protect the interest of host communities and allow for co-ownership of petroleum resources by the state government.

Removal of pollutants and accumulation of high-value cell inclusions in a batch reactor containing Rhodopseudomonas for treating real heavy oil refinery wastewater.

Treating wastewater using purple non-sulfur bacteria (PNSB) is an environmentally friendly technique that can simultaneously remove pollutants and lead to the accumulation of high-value cell inclusions. However, no PNSB system for treating heavy oil refinery wastewater (HORW) and recovering high-value cell inclusions has yet been developed. In this study, five batch PNSB systems dominated by Rhodopseudomonas were used to treat real HORW for 186 d. The effects of using different hydraulic retention times (HRT), sludge retention times (SRT), trace element solutions, phosphate loads, and influent loads were investigated, and the bacteriochlorophyll, carotenoid, and coenzyme Q10 concentrations were determined. The community structure and quantity of Rhodopseudomonas in the systems were determined using a high-sequencing technique and quantitative polymerase chain reaction technique. The long-term results indicated that phosphate was the limiting factor for treating HORW in the PNSB reactor. The soluble chemical oxygen demand (SCOD) removal rates were 67.03% and 85.26% without and with phosphate added, respectively, and the NH4+-N removal rates were 32.18% and 89.22%, respectively. The NO3--N concentration in the effluent was stable at 0-3 mg/L with or without phosphate added. Adding phosphate increased the Rhodopseudomonas relative abundance and number by 13.21% and 41.61%, respectively, to 57.35% and 8.52 × 106 gene copies/µL, respectively. The SRT was the limiting factor for SCOD removal, and the bacteria concentration was the limiting factor for nitrogen removal. Once the inflow load had been increased, the total nitrogen (TN) removal rate increased as the HRT increased. Maximum TN removal rates of 64.46%, 68.06%, 73.89%, 82.15%, and 89.73% were found at HRT of 7, 10, 13, 16, and 19 d, respectively. The highest bacteriochlorophyll, carotenoid, and coenzyme Q10 concentrations were 2.92, 4.99, and 4.53 mg/L, respectively. This study provided a simple and efficient method for treating HORW and reutilizing resources, providing theoretical support and parameter guidance for the application of Rhodopseudomonas in treating HORW.

Fatalities in Oil and Gas Extraction Database, an Industry-Specific Worker Fatality Surveillance System - United States, 2014-2019.

Problem/Condition: The U.S. oil and gas extraction (OGE) industry faces unique safety and health hazards and historically elevated fatality rates. The lack of existing surveillance data and occupational safety and health research called for increased efforts to better understand factors contributing to worker fatalities in the OGE industry. This report describes the creation of the Fatalities in Oil and Gas Extraction (FOG) database, presents initial findings from the first 6 years of data collection (2014-2019), highlights ways that FOG data have been used, and describes the benefits and challenges of maintaining the surveillance system. Period Covered: 2014-2019. Description of System: In 2013, the National Institute for Occupational Safety and Health (NIOSH) created the FOG database, a surveillance system comprising an industry-specific worker fatality database. NIOSH researchers worked with OGE partners to establish inclusion criteria for the database and develop unique database variables to elucidate industry-specific factors related to each fatality (e.g., phase of operation, worker activity, and working alone). FOG cases are identified through various sources, such as Occupational Safety and Health Administration (OSHA) reports, media reports, and notifications from professional contacts. NIOSH researchers compile source documents; OGE-specific database variables are coded by multiple researchers to ensure accuracy. Data collection ceased in 2019 because grant funding ended. Results: During 2014-2019, a total of 470 OGE worker fatalities were identified in the FOG database. A majority of these fatalities (69.4%) were identified from OSHA reports and Google Alerts (44.7% and 24.7%, respectively). Unique database variables created to characterize fatalities in the OGE industry (i.e., phase of operation, worker activity, working alone, and working unobserved) were identified in approximately 85% of OGE worker fatality cases. The most frequent fatal events were vehicle incidents (26.8%), contact injuries (21.7%), and explosions (14.5%). The event type was unknown among 5.7% of worker fatalities. Approximately three fourths of fatalities identified through the FOG database were among contractors. Approximately 20% of cases included workers who were working alone. Interpretation: The FOG database is a resource for identifying safety and health trends and emerging issues among OGE workers (e.g., exposure to hydrocarbon gases and vapors and fatalities resulting from cardiac events) that might not be available in other surveillance systems. The FOG database also helps researchers better identify groups of workers that are at increased risk for injury in an already high-risk industry. Challenges exist when maintaining an industry-specific surveillance system, including labor-intensive data collection, the need for researchers with substantial knowledge of the industry, delays in access to timely data, and missing source file data. Public Health Actions: Continued surveillance of worker fatalities in the OGE industry is recommended to help identify new safety and health hazards and guide research and prevention activities. Industry, academic institutions, and government can use findings from the FOG database to identify factors contributing to fatal injuries in OGE and develop interventions to improve worker safety and health. The findings in this report also can be used by other industries with high fatality rates to support the development of worker fatality surveillance systems.

Financial stability nexus with oil prices shocks and business cycle uncertainty during COVID-19: empirical trends of ASEAN economies.

This study aims to analyze the correlation between financial stability, oil price shocks, and business cycle uncertainty in the economies of the Association of Southeast Asian Nations (ASEAN) amidst the COVID-19 pandemic. This study examines the interplay and effects of various factors on the economic resilience of the ASEAN region, utilizing data from ten-member countries spanning the years 2002 to 2022. The results underscore the notable impact of oil price shocks on financial systems' stability, suggesting that oil price variations have the potential to disrupt financial markets, particularly in the context of the ongoing pandemic. Moreover, the research illustrates that the presence of business cycle uncertainty amplifies the negative consequences of oil price shocks, thereby heightening their influence on the financial system's stability. The study also uncovers a robust correlation between the COVID-19 pandemic and heightened levels of business cycle uncertainty within the ASEAN economies. The ongoing global pandemic has increased market volatility, a deceleration in economic growth, and disruptions in supply chains, generating a heightened sense of uncertainty within the business landscape. As a result, the heightened level of uncertainty has impeded the efficacy of monetary and fiscal policies in preserving financial stability.

Implementation of modified protocols under the principle of sustainability for seismic acquisition in lentic systems.

In order to use sustainable methodologies in the exploration of oil and gas in lentic aquatic systems, a modified methodology (MTR) was implemented in each phase. Simultaneously, water quality, sediment, and organisms were evaluated to detect possible effects. Results included non-compaction of the sediment and less resuspension of dissolved solids and nutrients. Effects such as the increase in blue-green algae and the decrease in benthic macroinvertebrates showed rapid recovery (<15 days) as well as the resuspension of sulfates. Finally, MTR Methodology was feasible, of low magnitude, punctual effect, and rapid recovery for the intervened aquatic systems.

Summer and winter variations of BTEX concentrations in an oil refinery complex and health risk assessment based on Monte-Carlo simulations.

The summer and winter concentrations of BTEX pollutants were investigated in various workplaces of an oil Refinery, Iran. In total 252 air samples from the breathing zones of the following employees were collected: supervisors, safetymen, repairmen, site men, and all workers. Carcinogenic and non-carcinogenic risk values were calculated based on the USEPA methodology using Monte Carlo simulations. BTEX concentrations were higher in the summer than in the winter season for all workstations, especially for toluene and ethylbenzene. The mean values of exposure to benzene for repairmen and site men were higher than threshold limit value of 1.60 mg/m3 for both seasons. Non-carcinogenic risk (HQ) values calculated for summer season for benzene, ethylbenzene, and xylene in all workstations, as well as for toluene for repairmen and site men exceeded acceptable level of 1. In winter season the mean HQ values for benzene and xylene in all workstations, for toluene for repairmen and site men, and for ethylbenzene for supervisors, repairmen, and site men were also > 1. For all workstations definite carcinogenic risk was indicated as calculated LCR values for benzene and ethylbenzene exposure were higher than 1 × 10-4 in both summer and winter seasons.

Sustainability of the anaerobic digestion of oil refinery secondary sludge.

Among the waste generated at oil refineries, secondary sludge from biological wastewater treatment processes (activated sludge systems) stands out. This paper aimed to assess the use of anaerobic digestion (AD) to treat sludge by SWOT (Strength, Weakness, Opportunity, and Threat) analysis, ranking the different factors based on sustainability criteria. Additionally, the SWOT factors were matched (TOWS matrix) to help interpret the results. AD was found to be compatible with sustainability. The results demonstrated that the strength of AD (reduced organic load) compensates for its weaknesses (need for operational control and initial implementation costs), thereby avoiding the threat (sludge composition) and making the most of the opportunity (lower disposal cost). AD and co-digestion (added with food waste) used to treat oil refinery sludge showed that around 60% of the factors analyzed were confirmed experimentally. It was concluded that AD should be considered in the sustainable treatment of oil refinery waste activated sludge, especially when mixed with other readily biodegradable wastes.

Anaerobic digestion (AD) is a potential treatment for secondary sludge from refineries.AD is compatible with sustainability.Anaerobic co-digestion of refinery sludge contributed positively to sustainable treatment.The strength (reduced organic load) of AD counteract its weaknesses (operational control and implementation costs).The threat of AD (sludge composition) should be avoided and the opportunity (low disposal cost) leveraged.

The effect of petroleum levels on some soil biological properties under phytoremediation and bioaugmentation.

With the development of industries and excessive use of petroleum compounds, petroleum pollution has become a serious threat to the environment. The aim of this study was to the effect of petroleum levels on the biological activities of soil affected by phytoremediation and bioaugmentation. A surface soil sample was collected from the polluted areas around Bandar Abbas Oil Refinery Company, and the petroleum-degrading bacteria were isolated. M. yunnanensis (native) was selected among the isolated colonies for further experiment. The used soil in this study was a surface soil collected from Baghu region of Bandar Abbas, Sothern Iran, and treatments were added to soil samples. To evaluate removal of petroleum levels (0, 4, and 8%) from the soil by phytoremediation (control, sorghum, barley, and bermudagrass) and bioaugmentation (control, A. brasilense (non-native) and M. yunnanensis) and bioaugmented phytoremediation, a factorial pot experiment with completely randomized design and three replications was performed. The results demonstrated that sorghum and bermudagrass were more resistant than barley to the toxic effects of petroleum. Positive effect of bacteria on dry weight in polluted soil was greater than in the non-polluted soil. The degradation of petroleum reaches 77% in sorghum + M. yunanesis + 4% petroleum. Plants had stronger ability to degrade total petroleum hydrocarbon (TPH), while bacteria could better degrade polyaromatic hydrocarbons (PAHs). Application of bacteria and plants stimulated soil biological characteristics (dehydrogenase, arylsulfatase, lipase, bacterial population, and respiration) in polluted soil. Among measured enzymes, dehydrogenase exhibited a stronger response to petroleum levels. Four-percent level had greater irritating effect on soil biological properties. Plants and bacteria rely on differences in biological properties to attain synergy in petroleum degradation. Results indicated that M. yunnanensis has a high ability to remove petroleum from soil, and plants enhance the efficiency of this bacterium.

Impact assessment of high-risk analytes in produced water from oil and gas industry.

This study characterizes and evaluates the constituents of produced water at production wells and dumping sites. The study examined the impact of offshore petroleum mining activities on aquatic systems for regulatory compliance and the selection of management and disposal options. The physicochemical analyses of produced water from the three study locations were within the permissible range for pH, temperature, and conductivity. Of the four heavy metals detected, mercury had the lowest concentration at 0.002 mg/L, while arsenic the metalloid, and iron had the highest concentrations at 0.038 mg/L and 36.1 mg/L, respectively. The total alkalinity values for the produced water in this study are about six-fold compared to the other three locations (Cape Three Point, Dixcove, University of Cape Coast). Compared to the other locations, produced water had higher toxicity to Daphnia, with an EC50 value of 80.3 %. The levels of polycyclic aromatic hydrocarbons (PAHs), volatile hydrocarbons, and polychlorinated biphenyls (PCBs) analyzed in this study were all insignificant in terms of toxicity. The total hydrocarbon concentrations indicated a high level of environmental impact. However, considering the possible breakdown of total hydrocarbons over time, and the marine ecosystem's high pH and salinity conditions, further recordings and observations should be conducted to ascertain the overall cumulative effects of oil drilling activities at the Jubilee oil fields along the shores of Ghana.

Ecological and human health risk assessment of polycyclic aromatic hydrocarbons (PAH) in Tigris river near the oil refineries in Iraq.

Recent Iraqi battles against ISIS in 2014 and 2015 resulted in the destruction or severe damage to several refineries' infrastructure. This, along with other factors, has led to the release and accumulation of a wide range of hazardous chemicals into the environment, for instance, polycyclic aromatic hydrocarbons (PAH). Thus, for the first time, a comprehensive 16 PAHs measurements campaign over the course of six months near the oil refineries along the Tigris River and its estuaries was investigated. The 16 PAHs concentrations in surface water and the sediments for the following oil refineries: Baiji, Kirkuk, Al-Siniyah, Qayyarah, Al-Kasak, Daura, South Refineries Company, and Maysan were examined. The overall findings indicated that the 16 PAHs concentrations ranged from 567.8 to 3750.7 ng/L for water and 5619.2-12795.0 ng/g for sediment. Water samples in South Refineries Company recorded the highest PAH concentrations while Baiji oil refinery registered the highest PAH concentrations in the sediment samples. The percentages of high molecular weight PAH (5-6 rings) in water and sediment samples were the highest, ranging from 49.41% to 81.67% and from 39.06% to 89.39% of total PAH for water and sediment, respectively. The majority of 16 PAHs measured in water and sediment samples of the Tigris River were derived from pyrogenic sources. Based on sediment quality guidelines (SQGs), most sites showed a possible effect range with occasional biological effects of most of the PAH concentrations in all sediments' samples. The calculated incremental lifetime cancer risk (ILCR) value was high risk with adverse health effects, including cancer.