Aromatic Hydrocarbons
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Synthesis ◽  
2022 ◽  
Author(s):  
Akira Shiozuka ◽  
Kohei Sekine ◽  
Yoichiro Kuninobu

Pyrene is one of the most attractive polycyclic aromatic hydrocarbons (PAHs) in photochemistry. Based on their redox properties, pyrenes have potential as photosensitizers. In this review, we aim to summarize recent developments in pyrene-catalyzed photoinduced organic reactions via the process of energy transfer or single electron transfer based on the excited state of pyrenes. 1. Introduction 2. Photolysis involving N–O bond cleavage or decarboxylation 3. (Cyclo)addition reactions with styrenes 4. Transformations via cleavage of C–F, C–I, C–S, and C–N bonds 5. Reactions based on sensitization-initiated electron transfer (SenI-ET) 6. Miscellaneous transformations 7. Conclusion


2022 ◽  
Vol 9 ◽  
Author(s):  
Beibei Liu ◽  
Lin Wu ◽  
Pan Pan ◽  
Ruilong Li ◽  
Bigui Lin

Root exudates play a pivotal role in the behaviors of polycyclic aromatic hydrocarbons (PAHs) in mangrove sediments, but the knowledge of how mangrove root exudates response to PAHs pollutants is limited. This study examined the root exudates of Bruguiera gymnorrhiza (L.) (B. gymnorrhiza) under exposure in phenanthrene, pyrene, and benzo[a]pyrene solution through a 45 days hydroponic cultivation. The results showed that the root exudates of B. gymnorrhiza were mainly hydrocarbon compounds. Tartaric acid was the dominant low molecular weight organic acids (LMWOAs) in root exudates. Under PAHs stress, the proportion of hydrocarbon compounds in root exudates decreased, while the proportion of amide compounds increased. At the first 15 days exposure, the amounts of dissolved organic carbon, soluble total sugars, total organic acids and LWMOAs all increased and reached the maximum values, subsequently, the amounts of root exudates had dropped. The degradation rates of PAHs followed the sequence of phenanthrene > pyrene > benzo [a] pyrene, and the presence of root exudates can significantly enhance the degradation of PAHs. The results illustrated that PAHs stress can significantly change the concentrations and species of root exudates. This study provides the scientific reference for understanding the ability of B. gymnorrhiza response to PAHs stress.


Author(s):  
Francesca Biandolino ◽  
Isabella Parlapiano ◽  
Lucia Spada ◽  
Antonella Di Leo ◽  
Maria Calò ◽  
...  

Abstract Objectives The paper evaluated the benefit and risk for human health associated with consumption of sea cucumber H. polii from Italian coasts (Central Mediterranean Sea). Materials and Methods body wall-BW, internal tunic-ITu, muscle bands-MB, alimentary canal-AC, gonad-Gd and respiratory tree-RT of H. polii were analyzed for proximate composition. Moreover, aminoacids, fatty acids and polycyclic aromatic hydrocarbons (PAHs) were determined with HPLC UV/Vis, GC-FID and GC-MS, respectively. Results Differences in the contents of Total Aminoacids (TAA) occurred based on tissue and sex, with AC and MB of female and Gd of male showing higher contents (range 47.8 -60.2 g/kg ww). Glycine and glutamic acid were the most abundant. Polyunsaturated (PUFA) was the major class of fatty acids and Arachidonic and Eicosapentaenoic (EPA) acids were the predominant PUFA. n-3 PUFA showed higher content in Gd, AC and RT indicating a higher quality. A favorable n-3/n-6 in the range 1.04-1.67 was observed. PAHs showed values ranged from 23 to 207 µg/kg ww with the highest levels in Gd-AC tissues and the lower in BW. Benzo[a]Pyrene, the most toxic compound, was detected in all tissues, of both sexes, at levels of 1.5-18 µg/Kg ww. Conclusion All tissues of H. polii, although with differences among them, are valuable food and can contribute for a healthy diet. Excess Cancer risk (CR) values for Gd and AC tissues, were above the considerable CR threshold of one in ten thousand established by USEPA, for high ingestion rate of these seafood.


2022 ◽  
Vol 51 (4) ◽  
pp. 883-904
Author(s):  
Elizaveta Faskhutdinova ◽  
Maria Osintseva ◽  
Olga Neverova

Introduction. Coal industry increases soil pollution with heavy metals and polycyclic aromatic hydrocarbons. Therefore, resoiling is an urgent problem that requires an immediate solution. The present research objective was to substantiate the use of microorganisms from mine tips in order to decrease soil pollution with heavy metals and oil compounds. Study objects and methods. The review featured five years of publications in Scopus, Web of Science, and Elibrary, which were subjected to analysis, systematization, and generalization. Results and discussion. Coal industry changes landscapes, flora, fauna, and soil microbiome. Bioremediation uses various microorganisms as means of resoiling. Some microorganisms isolated from coal mining waste are resistant to heavy metals and polycyclic aromatic hydrocarbons and are able to utilize them. For instance, such bacteria as Bacillus and Pseudomonas aeruginosa are capable of degrading oil pollutants. Microorganisms of Enterobacter and Klebsiella species were found to be resistant to copper, iron, lead, and manganese. Bacteria of the genera Bacillus, Arthrobacter, Pseudoarthrobacter, and Sinomonas are now to be resistant to nickel, arsenic, and chromium. Arbuscular mycorrhizal fungi increase the activity of soil enzymes, improve soil fertility, and decompose various organic compounds. Conclusion. Sequencing methods make it possible to determine the species composition of soils in mine tips in order to search for new strains capable of restoring former mining areas.


2022 ◽  
Vol 12 ◽  
Author(s):  
Yang Li ◽  
Wenjing Li ◽  
Lei Ji ◽  
Fanyong Song ◽  
Tianyuan Li ◽  
...  

The biodegradation of organic pollutants is the main pathway for the natural dissipation and anthropogenic remediation of polycyclic aromatic hydrocarbons (PAHs) in the environment. However, in the saline soils, the PAH biodegradation could be influenced by soil salts through altering the structures of microbial communities and physiological metabolism of degradation bacteria. In the worldwide, soils from oilfields are commonly threated by both soil salinity and PAH contamination, while the influence mechanism of soil salinity on PAH biodegradation were still unclear, especially the shifts of degradation genes and soil enzyme activities. In order to explain the responses of soils and bacterial communities, analysis was conducted including soil properties, structures of bacterial community, PAH degradation genes and soil enzyme activities during a biodegradation process of PAHs in oilfield soils. The results showed that, though low soil salinity (1% NaCl, w/w) could slightly increase PAH degradation rate, the biodegradation in high salt condition (3% NaCl, w/w) were restrained significantly. The higher the soil salinity, the lower the bacterial community diversity, copy number of degradation gene and soil enzyme activity, which could be the reason for reductions of degradation rates in saline soils. Analysis of bacterial community structure showed that, the additions of NaCl increase the abundance of salt-tolerant and halophilic genera, especially in high salt treatments where the halophilic genera dominant, such as Acinetobacter and Halomonas. Picrust2 and redundancy analysis (RDA) both revealed suppression of PAH degradation genes by soil salts, which meant the decrease of degradation microbes and should be the primary cause of reduction of PAH removal. The soil enzyme activities could be indicators for microorganisms when they are facing adverse environmental conditions.


Toxics ◽  
2022 ◽  
Vol 10 (1) ◽  
pp. 32
Author(s):  
Qianqian Xue ◽  
Yingze Tian ◽  
Xinyi Liu ◽  
Xiaojun Wang ◽  
Bo Huang ◽  
...  

Ambient PM2.5-bound ions, OC, EC, heavy metals (HMs), 18 polycyclic aromatic hydrocarbons (PAHs), 7 hopanes, and 29 n-alkanes were detected at Tuoji Island (TI), the only marine background atmospheric monitoring station in North China. The annual PM2.5 average concentration was 47 ± 31 μg m−3, and the average concentrations of the compositions in PM2.5 were higher in cold seasons than in warm seasons. The cancer and non-cancer risks of HMs and PAHs in cold seasons were also higher than in warm seasons. BaP, Ni, and As dominated the ∑HQ (hazard quotient) in cold seasons, while the non-carcinogenic risk in warm seasons was mainly dominated by Ni, Mn, and As. The ILCR (incremental lifetime cancer risk) values associated with Cr and As were higher in the cold season, while ILCR-Ni values were higher in the warm season. The backward trajectory was calculated to identify the potential directions of air mass at TI. Through the diagnostic ratios of organic and inorganic tracers, the sources of particulate matter in different directions were judged. It was found that ship emissions and sea salt were the main sources from marine directions, while coal combustion, vehicles emissions, industrial process, and secondary aerosols were the main source categories for inland directions. In addition, potential HM and PAH risks from inland and marine directions were explored. The non-cancerous effects of TI were mainly affected by inland transport, especially from the southeast, northwest, and west-northwest. The cancerous effects of TI were mainly simultaneously affected by the inland direction and marine direction of transport.


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