Direct and indirect photodegradation in aquatic systems mitigates photosensitized toxicity in screening-level substance risk assessments of selected petrochemical structures.

Photochemical processes are typically not incorporated in screening-level substance risk assessments due to the complexity of modeling sunlight co-exposures and resulting interactions on environmental fate and effects. However, for many substances, sunlight exerts a profound influence on environmental degradation rates and ecotoxicities. Recent modeling advances provide an improved technical basis for estimating the effect of sunlight in modulating both substance exposure and toxicity in the aquatic environment. Screening model simulations were performed for 25 petrochemical structures with varied uses and environmental fate properties. Model predictions were evaluated by comparing the ratios of predicted exposure concentrations with and without light to the corresponding ratios of toxicity thresholds under the same conditions. The relative ratios of exposure and hazard in light vs. dark were then used to evaluate how inclusion of light modulates substance risk analysis. Results indicated that inclusion of light reduced PECs by factors ranging from 1.1- to 63-fold as a result of photodegradation, while reducing PNECs by factors ranging from 1- to 49-fold due to photoenhanced toxicity caused by photosensitization. Consequently, the presence of light altered risk quotients by factors that ranged from 0.1- to 17-fold, since the predicted increase in substance hazard was mitigated by the reduction in exposure. For many structures, indirect photodegradation decreases environmental exposures independently of the direct photolysis pathway which is associated with enhanced phototoxicity. For most of the scenarios and chemicals in the present work, photosensitization appears to be mitigated by direct and indirect degradation from sunlight exposure.

Disentangling the History of Deep Ocean Disposal for DDT and Other Industrial Waste Off Southern California.

Ocean disposal of industrial waste from technical DDT [mainly 1,1'-(2,2,2-trichloroethane-1,1-diyl)bis(4-chlorobenzene), or 4,4'-DDT] manufacture occurred historically in the Southern California Bight. However, the paucity of historical records highlights uncertainties as to the mode, location, and timing of disposal or ongoing ecological effects of these wastes. This study combines sampling, chemical analysis, and numerical modeling of deep San Pedro Basin sediments revealing substantial DDT contamination that extends at least 25 km from the mainland. These findings narrate bulk DDT waste disposal to the offshore that peaked in the 1950s, prior to the onset of formal regulations; was agnostic to later-designated disposal sites; and has experienced sluggish transformation. Our findings further indicate an attenuating secondary source for the DDT daughter product, 1-chloro-4-[2,2-dichloro-1-(4-chlorophenyl)ethenyl]benzene (4,4'-DDE), which still deposits into deep San Pedro Basin sediments. While demonstrating the severity of DDT contamination to the region, these findings further define the burial potential of DDT wastes and inform the past, present, and future contamination potential that is needed to understand and predict ecological consequences. This work also points firmly to bulk, not containerized, disposal of DDT waste and to potential alternative contents of collocated waste.

Interplay Between Particle Size and Hierarchy of Zeolite ZSM-5 During the CO2 -to-aromatics Process.

The CO2 -to-aromatics process is a chemical reaction that converts carbon dioxide (CO2 ) into valuable petrochemical, i. e., aromatics (especially, benzene, toluene, and xylene) over the metal/zeolite bifunctional catalytic systems. These aromatics are used in producing plastics, fibers, and other industrial products, which are currently exclusively sourced from fossil-derived feedstocks. The significance of this process lies in its potential to mitigate climate change by reducing greenhouse gas emissions and simultaneously producing valuable chemicals. Consequently, these CO2 -derived aromatics can reduce the reliance on fossil fuels as a source of feedstocks, which can help to promote a more sustainable and circular economy. Owing to the existence of a wider straight channel favoring the aromatization process, zeolite ZSM-5 is extensively used to yield aromatics during CO2 hydrogenation over bifunctional (metal/zeolite) catalytic systems. To provide a better understanding of this unique property of zeolite ZSM-5, this work investigates the impact of particle size and hierarchy of the zeolite and how these govern the reaction performance and the overall selectivity. As a result, an improved understanding of the zeolite-catalyzed hydrocarbon conversion process has been obtained.

Isolation of a polyethylene-degrading bacterium, Acinetobacter guillouiae, using a novel screening method based on a redox indicator.

Plastic, a polymer synthesized from petrochemicals, is used worldwide. However, natural degradation of plastic is difficult, causing environmental pollution, with microplastics posing a serious threat to human health. In this study, we aimed to use a new screening method based on the oxidation-reduction indicator, 2,6-dichlorophenolindophenol, to isolate a polyethylene-degrading bacterium, Acinetobacter guillouiae, from insect larvae. Plastic-degrading strains are identified by the color change in the redox indicator from blue to colorless as plastic metabolism occurs. Polyethylene biodegradation by A. guillouiae was verified through weight loss, surface erosion, physiological evidence, and chemical changes on the plastic surface. In addition, we analyzed the characteristics of hydrocarbon metabolism in polyethylene-degrading bacteria. Results suggested that alkane hydroxylation and alcohol dehydrogenation were key steps in polyethylene degradation. This novel screening method will pave the way for high-throughput screening of polyethylene-degrading microorganisms and extending its application to other types of plastics may potentially address plastic pollution.

Tracing of Heavy Metals Embedded in Indoor Dust Particles from the Industrial City of Asaluyeh, South of Iran.

Assessment of indoor air quality is especially important, since people spend substantial amounts of time indoors, either at home or at work. This study analyzes concentrations of selected heavy metals in 40 indoor dust samples obtained from houses in the highly-industrialized Asaluyeh city, south Iran in spring and summer seasons (20 samples each). Furthermore, the health risk due to exposure to indoor air pollution is investigated for both children and adults, in a city with several oil refineries and petrochemical industries. The chemical analysis revealed that in both seasons the concentrations of heavy metals followed the order of Cr > Ni > Pb > As > Co > Cd. A significant difference was observed in the concentrations of potential toxic elements (PTEs) such as Cr, As and Ni, since the mean (±stdev) summer levels were at 60.2 ± 9.1 mg kg−1, 5.6 ± 2.7 mg kg−1 and 16.4 ± 1.9 mg kg−1, respectively, while the concentrations were significantly lower in spring (17.6 ± 9.7 mg kg−1, 3.0 ± 1.7 mg kg−1 and 13.5 ± 2.4 mg kg−1 for Cr, As and Ni, respectively). Although the hazard index (HI) values, which denote the possibility of non-carcinogenic risk due to exposure to household heavy metals, were generally low for both children and adults (HI < 1), the carcinogenic risks of arsenic and chromium were found to be above the safe limit of 1 × 10−4 for children through the ingestion pathway, indicating a high cancer risk due to household dust in Asaluyeh, especially in summer.

Recent advancements in hydrocarbon bioremediation and future challenges: a review.

Petrochemicals are important hydrocarbons, which are one of the major concerns when accidently escaped into the environment. On one hand, these cause soil and fresh water pollution on land due to their seepage and leakage from automobile and petrochemical industries. On the other hand, oil spills occur during the transport of crude oil or refined petroleum products in the oceans around the world. These hydrocarbon and petrochemical spills have not only posed a hazard to the environment and marine life, but also linked to numerous ailments like cancers and neural disorders. Therefore, it is very important to remove or degrade these pollutants before their hazardous effects deteriorate the environment. There are varieties of mechanical and chemical methods for removing hydrocarbons from polluted areas, but they are all ineffective and expensive. Bioremediation techniques provide an economical and eco-friendly mechanism for removing petrochemical and hydrocarbon residues from the affected sites. Bioremediation refers to the complete mineralization or transformation of complex organic pollutants into the simplest compounds by biological agents such as bacteria, fungi, etc. Many indigenous microbes present in nature are capable of detoxification of various hydrocarbons and their contaminants. This review presents an updated overview of recent advancements in various technologies used in the degradation and bioremediation of petroleum hydrocarbons, providing useful insights to manage such problems in an eco-friendly manner.

Emissions from the combustion of high-potential slurry fuels.

Slurry fuels based on wood and coal processing and petroleum refinery waste are an environmentally friendly and economically feasible alternative to the conventional solid fuel-coal. As part of this experimental research, we compared a set of fuels (coal and coal-water slurries with and without petrochemicals) by normalizing and calculating the specific concentrations of pollutants from their combustion. The pollutant concentrations were normalized with respect to the mass of burnt fuel, the thermal energy released by combustion, specific mass emissions per unit time, specific maximum mass emissions, and specific mass emissions per 1 kg of fuel equivalent or 1 MJ of thermal energy. The key objective of this research was to develop a method for comparing composite fuels in terms of their relative environmental friendliness. As part of the research, coal combustion was notable for the peak emissions of gaseous pollutants irrespective of the fuel mass and combustion chamber temperature. When slurries were burnt, CO2, SO2, and NOx concentrations were 12-90% lower as compared to coal. The research findings established that the most promising fuel of all the slurries under study is the one based on coal slime and sawdust due to its high environmental indicators.

Is exposure to hydrocarbons associated with chronic kidney disease in young Nigerians? A case-control study.

Introduction: Although environmental exposure to hydrocarbons has been linked to non-communicable diseases, its association with chronic kidney disease (CKD) is still an emerging area. Epidemiological studies associating CKD with prolonged exposure to hydrocarbons have mostly focused on occupational exposure, with fewer studies on environmental exposure from residing in contaminated areas. The aim of this study was to determine any association between long-term exposure to petrochemical products and the risk of CKD by comparing the residence and occupational history of young patients with CKD and non-CKD controls. Materials and methods: A case-control study of 74 cases and 74 age- and sex-matched non-CKD controls was carried out. Cases were patients with CKD who were aged 18-44 years and diagnosed with suspected chronic glomerulonephritis (CGN). Patients were recruited from an outpatient nephrology clinic and medical wards. Patients with CKD from traditional causes were excluded. Data were collected using a pre-tested structured questionnaire adapted from the WHO STEPwise approach to the non-communicable disease risk factor surveillance (STEPS) instrument. To assess exposure, a detailed work history and all residential addresses where the patients have lived for at least 5 years were recorded. 'Exposed' status was regarded as long-term residence in a known oil-polluted area and jobs involving crude oil exploration, processing, transportation and sales, and cleanup of crude oil hazards. Absence of a history of chronic exposure or any form of exposure was regarded as 'less exposed'. Results: There were 52 (70.3%) cases categorized as exposed, compared with 21 (28.4%) controls (p < 0.001). There were 34 (45.9%) cases born near petrochemical refineries and plants, compared with 11 (14.9%) controls (p ≤ 0.001). There were 34 (45.9%) cases residing near petrochemical refineries and plants, compared with 8 (10.9%) controls (p ≤ 0.001). When asked 'Do you think you have been significantly exposed to crude oil?', 15 (20.3%) cases and 2 (2.7%) controls answered 'yes' (p ≤ 0.001). Conclusion: Our findings suggest an association between exposure to petrochemicals and CKD in young Nigerians diagnosed with suspected CGN. Exposure is significantly associated with a higher mean age, waist circumference, and blood sugar levels; however, other traditional risk factors for CKD were not considerably more prevalent in this unique patient population. These findings should prompt more emphasis on occupational history, residential history, and other relevant environmental exposures in the assessment of patients at risk for CKD.

The role of biomaterials for the energy transition from the lens of a national integrated assessment model.

Integrated assessment models (IAMs) indicate biomass as an essential energy carrier to reduce GHG emissions in the global energy system. However, few IAMs represent the possibility of co-producing final energy carriers and feedstock. This study fills this gap by developing an integrated analysis of energy, land, and materials. This allows us to evaluate if the production of biofuels in a climate-constrained scenario can co-output biomaterials, being also driven by hydrocarbons/carbohydrates liquid streams made available from the transition to electromobility. The analysis was implemented through the incorporation of a materials module in the Brazilian Land Use and Energy System model. The findings show that bio-based petrochemicals account for 33% of the total petrochemical production in a stringent carbon dioxide mitigation scenario, in 2050. Most of this comes as co-products from facilities that produce advanced fuels as the main product. Moreover, from 2040 mobility electrification leads to the repurpose of ethanol for material production, compensating for the fuel market loss. Finally, the emergence of biorefineries to provide bio-based energy and feedstock reduces petroleum refining utilization in 2050, affecting the production of oil derivatives for energy purposes, and, hence, the GHG emissions associated with their production and combustion. SUPPLEMENTARY INFORMATION: The online version contains supplementary material available at 10.1007/s10584-021-03201-1.

Membranes for olefin-paraffin separation: An industrial perspective.

In the next decade, separation science will be an important research topic in addressing complex challenges like reducing carbon footprint, lowering energy cost, and making industrial processes simpler. In industrial chemical processes, particularly in petrochemical operations, separation and product refining steps are responsible for up to 30% of energy use and 30% of the capital cost. Membranes and adsorption technologies are being actively studied as alternative and partial replacement opportunities for the state-of-the-art cryogenic distillation systems. This paper provides an industrial perspective on the application of membranes in industrial petrochemical cracker operations. A gas separation performance figure of merit for propylene/propane separation for different classes of materials ranging from inorganic, carbon, polymeric, and facilitated transport membranes is also reported. An in-house-developed model provided insights into the importance of operational parameters on the overall membrane design.

Composition of a gas and ash mixture formed during the pyrolysis and combustion of coal-water slurries containing petrochemicals.

This paper presents the results of experimental research into the component composition of gases and ash residue from the combustion of a set of high-potential coal-water slurries containing petrochemicals. We have established that the use of slurry fuels provides a decrease in the CO2, CH4, SO2, and NOx concentrations as compared to those from coal combustion. The content of carbon monoxide and hydrogen in the gas environment from the combustion of slurries is higher due to the intense water evaporation. It is shown that adding biomass allows a further 5-33% reduction in the emissions of nitrogen and sulfur oxides as compared to the coal-water slurry and the composition with added waste turbine oil and a 23-68% decrease as compared to coal (per unit mass of the fuel burnt). The mechanisms and stages of CO2, SO2, and NOx formation are explained with a view to controlling gaseous anthropogenic emissions and ash buildup. The values of the relative environmental performance indicator are calculated for slurry fuels. It is shown to exceed the same indicator of bituminous coal by 28-56%.

The effects of exposure to crude oil or PAHs on fish swim bladder development and function.

The failure of the swim bladder to inflate during fish development is a common and sensitive response to exposure to petrochemicals. Here, we review potential mechanisms by which petrochemicals or their toxic components (polycyclic aromatic hydrocarbons; PAHs) may affect swim bladder inflation, particularly during early life stages. Surface films formed by oil can cause a physical barrier to primary inflation by air gulping, and are likely important during oil spills. The act of swimming to the surface for primary inflation can be arduous for some species, and may prevent inflation if this behavior is limited by toxic effects on vision or musculature. Some studies have noted altered gene expression in the swim bladder in response to PAHs, and Cytochrome P450 1A (CYP1A) can be induced in swim bladder or rete mirabile tissue, suggesting that PAHs can have direct effects on swim bladder development. Swim bladder inflation failure can also occur secondarily to the failure of other systems; cardiovascular impairment is the best elucidated of these mechanisms, but other mechanisms might include non-inflation as a sequela of disruption to thyroid signaling or cholesterol metabolism. Failed swim bladder inflation has the potential to lead to chronic sublethal effects that are as yet unstudied.

Industrial Applications of Terahertz Sensing: State of Play.

This paper is a survey of existing and upcoming industrial applications of terahertz technologies, comprising sections on polymers, paint and coatings, pharmaceuticals, electronics, petrochemicals, gas sensing, and paper and wood industries. Finally, an estimate of the market size and growth rates is given, as obtained from a comparison of market reports.

Bioconcentration factors for hydrocarbons and petrochemicals: Understanding processes, uncertainty and predictive model performance.

Fish bioconcentration factors (BCFs) are often used to assess substance-specific bioaccumulation. However, reliable BCF data are limited given the practical challenges of conducting such tests. The objectives of this paper are to describe nine rainbow trout studies performed in our lab using tailored dosing and test designs for obtaining empirical BCFs for 21 test substances; gain insights into the structural features and processes determining the magnitude and uncertainty in observed BCFs; and assess performance of six quantitative structure property relationships (QSPRs) for correctly categorizing bioaccumulation given current regulatory triggers. Resulting mean steady-state BCFs, adjusted to a 5% lipid content, ranged from 12 Lkg-1 for isodecanol to 15,448 Lkg-1 for hexachlorobenzene which served as a positive control. BCFs for hydrocarbons depended on aromatic and saturated ring configurations and position. Uptake clearances appeared to be modulated by gill metabolism and substance bioavailability, while elimination rates were likely influenced by somatic biotransformation. Current approaches for quantifying uncertainty in experimental BCFs, which take into account only variability in measured fish concentrations, were found to underestimate the true uncertainty in this endpoint with important implications for decision-making. The Vega (KNN/Read-Across) QSPR and Arnot-Gobas model yielded the best model performance when compared to measured BCFs generated in this study.

Prospects of thermal power plants switching from traditional fuels to coal-water slurries containing petrochemicals.

The amount of thermal and electric energy produced by coal combustion increases nonlinearly, because the production capacities and consumption of the corresponding energy are on the rise. The prospects of excluding coal from the picture are slim, because it has been traditionally considered one of the most attractive fuels in terms of cost and heat of combustion. What we need is major changes in the energy industry towards environmentally effective use of coals and their processing wastes. In this research, we show the possibility of coal-fired thermal power plants and steam shops switching to coal-water slurries containing petrochemicals (CWSP). Extra calculations are made for fuel oil and natural gas. The scientific novelty of the research consists in the comprehensive consideration of all the possible technological modifications in the fuel feeding, storage, and preparation system. We focus on potential benefits of thermal power plants and steam shops switching from coal, gas, and fuel oil to coal-water slurries containing petrochemicals, while taking into account all the main and most important environmental, economic, and energy performance indicators. Using CWSP instead of coal is much more environmentally friendly. By varying the content of water and additives in CWSP, we can lower the proportion of sulfur and nitrogen and slow down their oxidation. It is also possible to reduce temperature in the combustion zone and improve oxide retention in the ash without its release in the form of anthropogenic emissions. Throughout the world, tens of thousands of fuel oil and coal-fired TPPs with the annual gross electric output of 1.8 TW can switch to CWSP. The integrated performance indicators of CWSP fuels are only inferior to those of natural gas but these slurries are prepared from numerous industrial wastes.

Coal-water slurries containing petrochemicals to solve problems of air pollution by coal thermal power stations and boiler plants: An introductory review.

This introductory study presents the analysis of the environmental, economic and energy performance indicators of burning high-potential coal water slurries containing petrochemicals (CWSP) instead of coal, fuel oil, and natural gas at typical thermal power stations (TPS) and a boiler plant. We focus on the most hazardous anthropogenic emissions of coal power industry: sulfur and nitrogen oxides. The research findings show that these emissions may be several times lower if coal and oil processing wastes are mixed with water as compared to the combustion of traditional pulverized coal, even of high grades. The study focuses on wastes, such as filter cakes, oil sludge, waste industrial oils, heavy coal-tar products, resins, etc., that are produced and stored in abundance. Their deep conversion is very rare due to low economic benefit. Effective ways are necessary to recover such industrial wastes. We present the cost assessment of the changes to the heat and power generation technologies that are required from typical power plants for switching from coal, fuel oil and natural gas to CWSPs based on coal and oil processing wastes. The corresponding technological changes pay off after a short time, ranging from several months to several years. The most promising components for CWSP production have been identified, which provide payback within a year. Among these are filter cakes (coal processing wastes), which are produced as a ready-made coal-water slurry fuel (a mixture of flocculants, water, and fine coal dust). These fuels have the least impact on the environment in terms of the emissions of sulfur and nitrogen oxides as well as fly ash. An important conclusion of the study is that using CWSPs based on filter cakes is worthwhile both as the main fuel for thermal power stations and boiler plants and as starting fuel.

Environmental and biological monitoring of exposures to VOCs in a petrochemical complex in Iran.

Exposure to volatile organic compounds (VOCs) can cause cancers in human. This study aimed to measure the concentration of four VOCs including benzene, styrene, ethylbenzene, and phenol in ambient air of a petrochemical complex in Iran. Also, their urinary metabolites including phenol, mandelic acid (MA), and phenylglyoxylic acid (PGA) in the workers were monitored. Urine samples were collected before and after the 8-h workshift according to the NIOSH methods. They were analyzed by a gas chromatograph coupled with a flame ionization detector (GC-FID). High levels of the ambient VOCs were detected in the units of recovery and olefin. The levels of ethylbenzene and phenol were less than the guidelines suggested by NIOSH and ACGIH. However, in some cases, the amounts of benzene and styrene were higher than the guidelines. Excellent positive correlations were observed between VOCs exposure and their urinary metabolites (r 2 > 0.90), except for benzene (r 2 = 0.26). Our finding verified that urinary biomarkers can be applied as bioindicators for ambient exposure to VOCs. There is a risk of exposure to high levels of the pollutants in some of the sites, and it is necessary to adopt some preventive measures to reduce health risk.

Experimental evaluation of main emissions during coal processing waste combustion.

The total volume of the coal processing wastes (filter cakes) produced by Russia, China, and India is as high as dozens of millions of tons per year. The concentrations of CO and CO2 in the emissions from the combustion of filter cakes have been measured directly for the first time. They are the biggest volume of coal processing wastes. There have been many discussions about using these wastes as primary or secondary components of coal-water slurries (CWS) and coal-water slurries containing petrochemicals (CWSP). Boilers have already been operationally tested in Russia for the combustion of CWSP based on filter cakes. In this work, the concentrations of hazardous emissions have been measured at temperatures ranging from 500 to 1000°Ð¡. The produced CO and CO2 concentrations are shown to be practically constant at high temperatures (over 900°Ð¡) for all the coal processing wastes under study. Experiments have shown the feasibility to lowering the combustion temperatures of coal processing wastes down to 750-850°Ð¡. This provides sustainable combustion and reduces the CO and CO2 emissions 1.2-1.7 times. These relatively low temperatures ensure satisfactory environmental and energy performance of combustion. Using CWS and CWSP instead of conventional solid fuels significantly reduces NOx and SOx emissions but leaves CO and CO2 emissions practically at the same level as coal powder combustion. Therefore, the environmentally friendly future (in terms of all the main atmospheric emissions: CO, CO2, NOx, and SOx) of both CWS and CWSP technologies relies on low-temperature combustion.

Environmental indicators of the combustion of prospective coal water slurry containing petrochemicals.

Negative environmental impact of coal combustion has been known to humankind for a fairly long time. Sulfur and nitrogen oxides are considered the most dangerous anthropogenic emissions. A possible solution to this problem is replacing coal dust combustion with that of coal water slurry containing petrochemicals (CWSP). Coal processing wastes and used combustible liquids (oils, sludge, resins) are promising in terms of their economic and energy yield characteristics. However, no research has yet been conducted on the environmental indicators of fuels based on CWSP. The present work contains the findings of the research of CO, CO2, NOx, SOx emissions from the combustion of coals and CWSPs produced from coal processing waste (filter cakes). It is demonstrated for the first time that the concentrations of dangerous emissions from the combustion of CWSPs (carbon oxide and dioxide), even when combustible heavy liquid fractions are added, are not worse than those of coal. As for the concentration of sulfur and nitrogen oxides, it is significantly lower for CWSPs combustion as compared to coals. The presented research findings illustrate the prospects of the wide use of CWSPs as a fuel that is cheap and beneficial, in terms of both energy output and ecology, as compared to coal.