Outdoor cultivation and metabolomics exploration of Chlamydomonas engineered for bisabolene production.

Demonstrating outdoor cultivation of engineered microalgae at considerable scales is essential for their prospective large-scale deployment. Hence, this study focuses on the outdoor cultivation of an engineered Chlamydomonas reinhardtii strain, 3XAgBs-SQs, for bisabolene production under natural dynamic conditions of light and temperature. Our preliminary outdoor experiments showed improved growth, but frequent culture collapses in conventional Tris-acetate-phosphate medium. In contrast, modified high-salt medium (HSM) supported prolonged cell survival, outdoor. However, their subsequent outdoor scale-up from 250 mL to 5 L in HSM was effective with 10 g/L bicarbonate supplementation. Pulse amplitude modulation fluorometry and metabolomic analysis further validated their improved photosynthesis and uncompromised metabolic fluxes towards the biomass and the products (natural carotenoids and engineered bisabolene). These strains could produce 906 mg/L bisabolene and 54 mg/L carotenoids, demonstrating the first successful outdoor photoautotrophic cultivation of engineeredC. reinhardtii,establishing it as a one-cell two-wells biorefinery.

Techno-economic feasibility of a recycling plant for the extraction of metals and boehmite from hazardous petroleum spent catalysts.

Petroleum spent hydroprocessing catalysts are hazardous solid waste, the efficient recycling of which is a serious challenge to refineries. However, information on the economic feasibility of spent catalysts recycling plants is scarce, which is critical for environmental authorities and decision-makers. In this work, an innovative recycling scheme targeting hydrometallurgical recovery of base metals (Ni, Mo, and V) and transforming low-value Al residue into a high-value boehmite (γ-AlOOH) as the key product was considered an efficient way to beneficiate the hazardous spent hydroprocessing catalysts. A preliminary techno-economic evaluation of such a recycling scheme was performed to assess the feasibility of the proposed recycling scheme. The recovery cost (valuable metals and boehmite) and potential revenue were estimated to study the economics of the process. The preliminary results have suggested that the recycling scheme is economically feasible with a high internal rate of return (IRR) of 12.3%, a net present value of 38.6 million USD, and a short payback period of 8.7 years. Furthermore, a sensitivity analysis (± 10%) conducted on key parameters showed that the selling prices of the finished products and the cost of chemicals were the most important factors affecting plant economics. Overall, the recycling scheme was sustainable and avoided landfilling of spent catalysts as the residue can be beneficiated into a high-value product. The results from the economic feasibility study are likely to assist the stakeholders and decision-makers in making investment and policy decisions for the valorization of spent hydroprocessing catalysts.

Performance of electro-Fenton process for the treatment of synthetic sulphidic spent caustic waste stream generated from petroleum refineries.

Sulphidic spent caustic (SSC) is an alkaline waste stream which is generated during caustic scrubbing of liquefied petroleum gas and ethylene products. Due to presence of high concentrations of sulphides and phenols, the waste stream requires proper treatment before mixing with the low strength wastewater streams produced from other refinery operations. Electrochemical process is an emerging treatment method that can work efficiently at ambient conditions. The present study reports performance of electro-Fenton (EF) process for the treatment of synthetic SSC wastewater (sulphides = 10 g L-1, phenol = 2 g L-1 and pH = 12.9). The EF runs were carried out for 2 h duration in a reactor equipped with iron electrodes. The effects of H2O2 dose (0.26-1.3 M), current density (1-20 mA cm-2), pH (4.5-12.9) and stirring speed (100-1000 rpm) were investigated on removal of pollutants. The H2O2 was rapidly consumed in initial 30 min during which the significant fraction of the pollutants was degraded or removed. The optimum conditions for EF process were found to be as follows: pH = 4.5, H2O2 dose = 1.05 M, current density = 5 mA cm-2 and stirring speed = 500 rpm. At these conditions, the maximum sulphide and phenol removals from the wastewater were 98% and 91%, respectively. The results will be helpful to the wastewater treatment plant operators worldwide dealing with high concentrations of such pollutants.

A novel physical-biochemical treatment of refinery wastewater.

As of 2022, China has achieved a crude oil processing capacity of 918 million tons, leading to a notable escalation in the production of refinery wastewater. The composition of refinery wastewater is intricate and diverse, posing a substantial challenge to its treatment. In order to facilitate appropriate discharge or reuse, an exhaustive separation process is imperative for refinery wastewater. Conventional pre-treatment processes typically employ inclined plate separators and dissolved air flotation (DAF) for the removal of oil and suspended solids (SS), while sequencing batch reactor (SBR), oxidation ditch, or biological aerated filter (BAF) are employed for the biological treatment process. However, these approaches encounter challenges such as a large spatial footprint, suboptimal treatment efficiency, and high energy consumption. In response to these challenges, this study introduces a novel integrated apparatus consisting of a high-efficiency oil remover (HEOR), coalescence oil remover (COR), and an airlift-enhanced loop bioreactor (AELR). A pilot-scale test was conducted to evaluate the performance of this integrated system in practical field applications. The pilot-scale tests reveal that, without the addition of chemical agents, the petroleum removal efficiency of "HEOR + COR" system was 1.2 times that of DAF. Compared with the SBR system, AELR's volume loading was increased by 1.56 times. The effluent quality achieved in the pilot-scale tests attained parity with that the original process. The "HEOR + COR + AELR" system exhibited energy and carbon emissions reduction of 28% and 30% compared to the "DAF + SBR" system, respectively. Therefore, the operating costs was reduced by approximate 1 Chinese Yuan (CNY) per ton of treated water. This technological advancement serves as a valuable reference for the implementation of low-carbon treatment of refinery wastewater.

Response surface methodology optimization of the effect of pH, contact time, and microbial concentration on chemical oxygen removal potential of vegetable oil industrial effluents.

The vegetable oil refinery industry generates highly polluted effluents during oil production, necessitating proper treatment before discharge to prevent environmental hazards. Treating such wastewater has become a major environmental concern in developing countries. Chemical oxygen demand (COD) is a key parameter in assessing the wastewater's organic pollutant load. High COD levels can lead to reduced dissolved oxygen in water bodies, negatively affecting aquatic life. Various technologies have been employed to treat oily wastewater, but microbial degradation has gained attention due to its potential to remove organic pollutants efficiently. This study aims to optimize the biodegradation treatment process for vegetable oil industrial effluent using response surface methodology (RSM). The wastewater's physicochemical properties were characterized to achieve this, and COD removal was analyzed. Furthermore, RSM was used to investigate the combined effects of pH, contact duration, and microbial concentration on COD removal efficiency. The result showed that the microbial strain used recorded a maximum COD removal of 92%. Furthermore, a quadratic model was developed to predict COD removal based on the experimental variables. From the analysis of variance (ANOVA) analysis, the model was found to be significant at p < 0.0004 and accurately predicted COD removal rates within the experimental region, with an R2 value of 90.99% and adjusted R2 value of 82.89%. Contour plots and statistical analysis revealed the importance of contact duration and microbial concentration on COD removal. PRACTITIONER POINTS: Response surface methodology (RSM) optimization achieved a significant chemical oxygen demand (COD) removal efficiency of 92% in vegetable oil industrial effluents. The study's success in optimizing COD removal using RSM highlights the potential for efficient and environmentally friendly wastewater treatment. Practitioners can benefit from the identified factors (pH, contact time, and microbial concentration) to enhance the operation of treatment systems. The developed predictive model offers a practical tool for plant operators and engineers to tailor wastewater treatment processes. This research underscores the importance of sustainable practices in wastewater treatment, emphasizing the role of microbial degradation in addressing organic pollutant loads.

Petroleum wastewater: Environmental protection, treatment, and safe reuse: An overview.

Oil petroleum production consumes about 1.0-7.2 bbl. The needed water for such production ranges between 0.47 and 7.2 L water to 1.0 L crude. Between 80 and 90% of the consumed water is disposed of as wasted effluents. Consequently, there is an important connection between petroleum production and the contamination of the environment and surface water in addition to their ecotoxicological effects. The objective of the present review is to through light on the hazardous impact of petroleum wastewater on the environment and water ways. The present study presents several wastewater treatment technologies in handling the petroleum produced water (PPW) and reducing the hazardous impact to the environment. Safe reuse is also presented including simple, advanced, and environmentally friendly techniques. The reported treatment technologies are divided into five main categories: membrane technologies, biological treatment processes, electro-chemical coagulation, physical/chemical treatment processes (dissolved air flotation (DAF)/air flotation (IAF), adsorption, and chemical flocculation), and catalytic oxidation including chemicals such as advanced and Fenton oxidation processes (AOPs). The analysis and observation of each treatment process are also presented. Implementing of these processes in sequential and/or in combined to avoid the drawbacks of any poor treatment are discussed. The present review discusses; also, in detail each of these treatment technologies and their efficiency including the observation and conclusions of each one. The study shows; also; how the final treated effluent can be reused for non-potable purposes as an additional water resource according to the degree of decontamination. An additional advantage of treatment is protection of both the environment and the water ways by avoiding any discharge of such hazardous wastewater.

Valorization and co-treatment of hazardous petroleum refinery oily sludge and sewage associated with bioenergy recovery in tubular microbial fuel cell.

Petroleum refineries generate large amounts of oily sludge which is normally loaded with different residual hazardous petroleum derivatives. Also, the residential complexes affiliated to the petroleum refineries generate considerable volumes of sewage. This study was devoted to investigate the potential of energy recovery from co-bioelectrochemical treatment of petroleum refinery oily sludge (PROS) and sewage using a tubular dual-chambers microbial fuel cell (MFC). Initially, the MFC was operated in a fill and draw mode of 4 cycles, each cycle at a different organic load (OL). The results revealed that maximum removal efficiencies of the organic content as COD were 93.67%, 98.57%, 99.64%, and 99.74%, whereby maximum power outputs were 225 ± 10, 324 ± 7, 1230 ± 18, and 1156 ± 14 mW/m3 for cycle1of OL1 (1138 ± 60 mg/L), cycle2 of OL2 (7000 ± 75 mg/L), cycle3 of OL3 (13,890 ± 50 mg/L), and cycle4 of OL4 (17,100 ± 150 mg/L), respectively. Based on those promising results, the MFC was operated continually for 60 days by feeding the MFC with PROS and sewage at organic loading of 13,000 ± 1000 mg/L. Significant results concerning COD and TPH elimination efficiency > 99.85% and 94.12%, respectively were obtained associated with power output of 1225 ± 25 mW/m3.

Investigation of a membrane bioreactor's performances in treating sunflower oil refinery wastewater containing high oleic acid at different SRTs.

This study investigated the MBR performance, sludge morphology, and membrane fouling potential in treating sunflower oil refinery wastewater containing high oleic acid at three different SRTs of 10 days, 40 days, and infinite. The analysis of mixed liquor morphology including sludge volume index, PSD, EPS, and SMP showed that the sludge flocs compressibility and bioflocculation considerably improved at 40-days SRT. Additionally, at this SRT, the mixed liquor O&G, COD, and SMP accumulation were low, and the microbial activity and COD removal were enhanced. The gas chromatography/mass spectrometry analysis results confirmed the formation of three different new compounds related to non-readily biodegradable recalcitrant oily compounds and SMP at all SRTs. The analysis of mixed liquor EPS, PSD, SMP, and effluent COD at three different SRTs suggests that under the industrial conditions of MBR operation treating SORW with high oleic acid, the optimal operating conditions are predicted to be at 40-days SRT.

Assessment of the internal and external exposure risks to methylsiloxanes in communities near a petroleum refinery.

Methylsiloxanes (MSs) are widely used in industrial production and have attracted much attention due to their potential health risks to humans. MSs are present in emissions from petroleum refining, and it is therefore important to assess the health risks to residents living near refineries. In this study, we evaluated the pollution characteristics and human exposure risks of three cyclic MS (CMS) oligomers (D4-D6) in areas upwind and downwind of a petroleum refinery. The concentrations of total CMSs were 4-33 times higher in the downwind than upwind areas. At the same sampling site, the concentrations of CMSs were higher indoors than outdoors. The maximum concentration of CMSs was found in the indoor environment 200 m downwind of the petroleum refinery (75 µg/m3 in air and 2.3 µg/g in dust). The concentrations and detection rates of CMSs in plasma samples were higher in the downwind than upwind residents. Although residents living downwind of the petroleum refinery were a non-occupationally exposed population, they should be considered a highly CMS-exposed population because of their extremely high internal exposure doses. Inhalation exposure was the main source of CMSs in the plasma of these residents. When different exposure pathways were investigated, inhalation exposure was the major contributor to the average daily dose in residents of locations near the petroleum refinery, whereas the dermal absorption of personal care products was the major contributor at other sites. Although the overall risks of exposure to total CMSs were below the chronic reference dose for all exposure pathways, the combined joint toxic effects of various CMSs remain unclear. Further studies are therefore required to determine the exposure risks and subsequent health effects of CMSs for the residents of these areas.

REPSOL oil spill off Central Perú in January 2022: A modeling case study.

This study simulates the spillage of 1460 metric tons of oil that occurred in January 2022 off La Pampilla Refinery, in central Perú. The oil slick was predominantly displaced northward along the coastline, driven by prevailing currents and winds in the region. The weathering analysis revealed that the removal of oil was mainly due to evaporation (28%) and beaching processes (70%) within 96 h after the initial release. The coastal areas spanning from Ventanilla to Punta Chancay experienced significant impacts from the oil spill, representing 96% of the total affected coastal extent. Specifically, Ventanilla and Santa Rosa Beaches and the National Reserve System of Islands were heavily impacted during the first 24 h, while the surroundings of Ancón Bay, Aucallama and Pasamayo beaches were affected after two days. This modeling case study provides valuable insights into the fate and transport of the Repsol oil spill.

Treatment vegetable oil refinery wastewater by sequential electrocoagulation-electrooxidation process.

In the present study a sequential process composed of electrocoagulation (EC) followed by electrooxidation (EO) was utilized at the laboratory scale to remove the chemical oxygen demand (COD) from wastewater generated in Iraqi vegetable oil refinery plant.in the EC, impacts of operating variables such as current density (10-30 mA cm-2) and pH (4-10),and EC time (30-90 min) on the COD removal (RE%) were investigated using response surface methodology (RSM) based on Box- Behnken design(BBD). a mathematical correlation that relates the operating factors with RE% was developed and its regression coefficient was 99.02% confirming the significant of the model. Response surface plots showed that RE% increased with increasing current density and time while it decreased with increasing pH. The optimum removal with a lower cost for EC process were achieved at current density of 30mA/cm2, pH of 4, and electrolysis time of 90 min in which RE% of 69.19% was obtained with requirement of 0.513kWh/kg COD as specific energy consumption (SEC). The effluent exit from EC was treated by EO for a period of 240min at a current density of 30mA/cm2 and an initial pH value of 4 to obtain RE% of 96% at SEC of 1.554 kWh/kg COD. Combining EC with EO resulted in a total RE% of 98.72% and a total SEC of 2.067 kWh/kg COD. Based on the results of present study, the applicability of a sequential electrocoagulation-electrooxidation process for treatment vegetable oil wastewaters is feasible.

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.

Comparative assessment of soil microbial community in crude oil contaminated sites.

Petroleum refineries generate oily sludge that contains hazardous polycyclic aromatic hydrocarbons (PAH), and hence, its proper disposal is of foremost concern. Analysis of the physicochemical properties and functions of indigenous microbes of the contaminated sites are essential in deciding the strategy for bioremediation. This study analyses both parameters at two geographically distant sites, with different crude oil sources, and compares the metabolic capability of soil bacteria with reference to different contamination sources and the age of the contaminated site. The results indicate that organic carbon and total nitrogen derived from petroleum hydrocarbon negatively affect microbial diversity. Contamination levels vary widely on site, with levels of PAHs ranging from 5.04 to 1.66 × 103 µg kg-1 and 6.20 to 5.64 × 103 µg kg-1 in Assam and Gujarat sites respectively, covering a higher proportion of low molecular weight (LMW) PAHs (fluorene, phenanthrene, pyrene, and anthracene). Functional diversity values were observed to be positively correlated (p < 0.05) with acenaphthylene, fluorene, anthracene, and phenanthrene. Microbial diversity was the highest in fresh oily sludge which decreased upon storage, indicating that immediate bioremediation, soon after its generation, would be beneficial. Improvement in the bio-accessibility of hydrocarbon compounds by the treatment of biosurfactant produced by a (soil isolate/isolate) was demonstrated., with respect to substrate utilization.

Comparative chemical analysis, mutagenicity, and genotoxicity of Petroleum refinery wastewater and its contaminated river using prokaryotic and eukaryotic assays.

Concern on the toxicity of final wastewater generated by the petroleum refining industry has increased in recent years due to the potential health threats associated with their release into the waterways. This study determined the mutagenic and genotoxic potential of petroleum refinery wastewater and a receiving river using the Ames fluctuation test on Salmonella typhimurium strains TA100 and TA98, SOS chromotest on Escherichia coli PQ37, and piscine peripheral micronucleus (MN) assay. Analyses of the physicochemical parameters, heavy metal, and organic contents of the samples were also performed. Ames test result showed that the two tested samples were mutagenic with TA100 strain as the more responsive strain for both the refinery wastewater and the river sample in terms of the calculated mutagenic index. A similar result was obtained in the SOS chromotest; however, the E. coli PQ37 system recorded a slightly higher sensitivity for detecting genotoxins than the Salmonella assay in the two samples. MN data showed induction of a concentration-dependent significant (p < 0.05) increase in the frequency of MN by both samples when compared with the negative control. Generally, the refinery wastewater induced the highest mutagenicity and genotoxicity compared to the river sample in the three assays used. Haemoglobin, platelets, red blood cells, mean corpuscular volume, total white blood cells, heterophils, haematocrit, and eosinophils reduced significantly with increased lymphocytes, basophils, mean corpuscular haemoglobin, and mean corpuscular haemoglobin concentration in fishes exposed to both samples. Total petroleum hydrocarbon, benzene, toluene, phenol index, polycyclic aromatic hydrocarbons, cadmium, mercury, nickel, lead, and vanadium contents analysed in the samples were believed to be responsible for the observed genotoxicity and mutagenicity. The findings of this study revealed that petroleum refinery wastewater is a potential mutagenic and genotoxic risk to the environment.

Source and composition analysis of petroleum hydrocarbons in the refinery circulating water.

Oil leakage from water coolers in refinery circulating water occurs from time to time, which affects the long-term and stable operation of refinery units. So far, workers in the refineries still adopt manual check methods, opening water coolers one by one and checking the water's smell and color to find out the spilled water coolers. In this study, a more rapid method of source appointment of oil spill in the circulating water by combining chemical fingerprinting with model recognition was developed. Firstly, chemical fingerprints including benzene/naphthalene series, and light hydrocarbon (C3-C5) in oil samples from all water coolers in the refinery fluid catalytic cracking (FCC) unit were analyzed by gas chromatography-mass spectrometry (GC/MS). Gasoline, diesel, and poor oil could be distinguished in terms of benzene and naphthalene distribution. The three similar types of gasolines could be distinguished by the volatile hydrocarbons especially C3-C4. The classification model for the spill of gasoline, diesel, and poor oil in circulating water was constructed by the partial least squares discriminant analysis algorithm with a 100% correct classification rate at the concentration more than 10 ppm. The gasoline spills in the circulating backwater of the refinery were successfully recognized by the classification model. This method enables the rapid prediction of oil spill type in refinery circulating water, and a similar method by installing online instrument and software potentially can be used for monitoring the circulating water in real time.

Petroleum refinery effluent contribution to chemical mixture toxic pressure in the environment.

Petroleum refinery effluents (PRE) are wastewaters from industries associated with oil refining. Within Europe, PREs are regulated through local discharge permits and receive substantial treatment before emission. After treatment, PREs can still contain low levels of various pollutants potentially toxic to organisms. Earlier work, including whole-effluent toxicity assessments, has shown that the toxicity of permitted PREs is often limited. However, the extent to which PREs contribute to chemical pollution already present in the receiving environment is unknown. Therefore, our study aimed to assess the contribution of PREs to mixture toxic pressure in the environment, using the multi-substance potentially affected fraction of species (msPAF) as an indicator. Based on measured chemical concentrations, compiled species sensitivity distributions (SSD) and a mechanistic solubility model, msPAF levels were estimated for undiluted effluents at discharge points and diluted effluents downstream in receiving waters. Median msPAF-chronic and msPAF-acute levels of PREs at discharge points were 74% (P50) and 40% (P95), respectively. The calculated msPAF levels were reduced substantially to <5% downstream for most effluents (82%), indicating low to negligible toxicity of PREs in receiving environments beyond the initial mixing zone. Regardless of differences in endpoints and locations, hydrocarbons (mainly total petroleum hydrocarbons) and inorganics (mainly ammonia) explained at least 85% of the mixture toxic pressure. The msPAF levels of PREs were on average 2.5-4.5 orders of magnitude lower than msPAF levels derived from background pollution levels, suggesting that PREs were minor contributors to the toxic pressure in the environment. This study presents a generic methodology for quantifying the potential toxic pressure of PREs in the environment, identifying hotspots where more effective wastewater treatment could be needed. We explicitly discuss the uncertainties for further refinement and development of the method.

Health status of petrochemical workers: a narrative review.

SUMMARY: Professional exposure to benzene has been extensively investigated by occupational medicine, leading to strict regulation of exposure threshold values. However, the petrochemical industry utilizes many chemical substances, whose exposure, without effective control and mitigation actions, could influence the health status over time. The aim of this narrative review is to describe health status of petrochemical workers related to occupational exposures, inquiring literature from 1980 to present. We used the PubMed and Web of Science search engines. As regards non-neoplastic diseases, despite heterogeneous prevalence estimates, we could say that standardized mortality rate (SMR) for hypertension, hypercholesterolemia and diabetes does not increase overall, compared to reference populations; a possible explanation may be the "healthy worker effect". Attention should be paid to color disperception and respiratory symptoms, due to toxic or irritating substances exposure. Studies concerning neoplastic pathology have mainly investigated mortality outcomes, finding no increase in cancer, except for melanoma or other skin cancers and leukemia. As regards the former, however, it is not excluded that other risk factors may contribute (e.g. UV rays in offshore workers), while for leukemia, only the most recent studies have analyzed various subtypes of hematopoietic tumors, highlighting a possible risk for the development of myelodysplastic syndrome. The risk of pleural mesothelioma was also increased, likely due to asbestos exposures, while the risk of death from prostate cancer remains controversial.

Health risk assessment of volatile organic compounds (VOCs) in a refinery in the southwest of Iran using SQRA method.

Oil industries, such as oil refineries, are important sources of volatile organic compound production. These compounds have significant health effects on human health. In this study, a health risk assessment is carried out on volatile organic compounds (VOCs) in the recovery oil plant (ROP) unit of a refinery in southwest Iran. It was performed using the SQRA method including respiratory risk for chronic daily intake (CDI) of VOCs and cancer risk and non-cancer risk indices. Five locations in the area of oil effluents and five locations in the refinery area (control samples) were considered for evaluation. The sampling was done according to the standard NIOSH-1501 and SKC pumps. The gas chromatography/flame ionization detector (GC/FID) method was used to extract VOCs. The cancer slope factor (CSF) and respiratory reference dose (RFC) were calculated in addition to the respiratory risk (CDI). The end result shows that a significant difference was observed between the concentrations of volatile organic compounds in the two groups of air (P < 0.05). The SQRA risk assessment showed that the risk levels of benzene for workers in the pit area were very high (4-5). Health hazard levels were also evaluated as high levels for toluene (2-4) and moderate levels for xylene and paraxylene (1-3). The cancer risk assessment of volatile organic compounds recorded the highest level of cancer risk for benzene in the range of petroleum effluents (>1). Also, a non-cancer risk (HQ) assessment revealed that benzene had a significant health risk in the range of oil pits (2-3). Based on the results, petroleum industries, including refineries, should conduct health risk assessment studies of volatile organic compounds. The units that are directly related to the high level of VOCs should be considered sensitive groups, and their employees should be under special management to reduce the level of exposure to these compounds and other hazardous compounds.

Identification of cultivable bacterial strains producing biosurfactants/bioemulsifiers isolated from an Algerian oil refinery.

Algerian petrochemical industrial areas are usually running spills and leakages of hydrocarbons, which constitutes a major source of toxic compounds in soil such as aromatic hydrocarbons. In this paper, samples of crude oil-polluted soil were collected from Skikda's oil refinery and were subjected to mono and polyaromatic hydrocarbons threshold assessment. Soil physicochemical parameters were determined for each sample to examine their response to pollution. Amid 34 isolated bacteria, eleven strains were selected as best Biosurfactants (Bs)/Bioemulsifiers (Be) producers and were assigned to Firmicutes and Proteobacteria phyla based on molecular identification. Phylogenetic analysis of partial 16S rDNA gene sequences allowed the construction of evolutionary trees by means of the maximum likelihood method. Accordingly, strains were similar to Bacillus spp., Priesta spp., Pseudomonas spp., Enterobacter spp. and Kosakonia spp. with more than 95% similarity. These strains could be qualified candidates for an efficient bioremediation process of severally polluted soils.

Distribution, source, and health risk assessment of polycyclic aromatic hydrocarbons in the soils from a typical petroleum refinery area in south China.

The ubiquity of polycyclic aromatic hydrocarbons (PAHs) in soils in petroleum refining areas is an important problem affecting human and ecological safety. In this study, 103 topsoil (0-0.50 m) samples were collected from a retired petroleum refinery area in Guangdong province, south China. The PAHs concentrations were determined by ultrasonic extraction and gas chromatography-mass spectrometry detection methods. Twelve PAHs controlled priority listed by the US Environmental Protection Agency (USEPA) were investigated. The results revealed that the concentration of Æ©12PAHs ranged from 2100 to 5200 µg kg-1, with a mean value of 3741.66 µg kg-1. The site was dominated by high rings PAHs (4-, 5-, and 6-ring), contributing 81.96% to Æ©12PAHs. The concentrations of 9 kinds of PAHs exceeded the Dutch soil quality standard. Besides, the PAHs were primarily distributed in the storage tank area and with high levels of contamination. The results of hierarchical cluster analysis (HCA) and principal component analysis (PCA) indicated that coal combustion was the source of PAHs in topsoil, followed by petroleum dripping and traffic emissions. The incremental lifetime cancer risk (ILCR) modeling illustrated that soil ingestion was the major pathway of PAH exposure for both adults and children. Notably, the total noncarcinogenic human health risk due to PAHs was within the limit of 1, while the carcinogenic risks alone caused by benzo(a)pyrene via soil ingestion to adults and children were obviously beyond the USEPA limit (1.00E -06). Therefore, PAHs in the petroleum refinery areas have potential carcinogenic hazards to human health, the area should be remediated before reuse.