Littérature scientifique sur le sujet « Polycyclic musk »
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Articles de revues sur le sujet "Polycyclic musk"
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Herren, D., et J. D. Berset. « Nitro musks, nitro musk amino metabolites and polycyclic musks in sewage sludges ». Chemosphere 40, no 5 (mars 2000) : 565–74. http://dx.doi.org/10.1016/s0045-6535(99)00325-2.
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Smyth, Shirley Anne, Lori A. Lishman, Edward A. McBean, Sonya Kleywegt, Jian-Jun Yang, M. Lewina Svoboda, Sandra Ormonde, Vince Pileggi, Hing-Biu Lee et Peter Seto. « Polycyclic and Nitro Musks in Canadian Municipal Wastewater : Occurrence and Removal in Wastewater Treatment ». Water Quality Research Journal 42, no 3 (1 août 2007) : 138–52. http://dx.doi.org/10.2166/wqrj.2007.018.
Texte intégralRésumé :
Abstract The removal and/or partitioning (to sludge) of six polycyclic and five nitro musks through the liquid treatment train of a conventional Canadian secondary activated sludge wastewater treatment plant is characterized. Raw influent, primary effluent, secondary effluent, primary sludge, and waste activated sludge concentrations were correlated to seasonal process temperatures (warm, 22°C; cold, 15°C). Maximum influent concentrations of polycyclic and nitro musks were 7,030 ± 2,120 ng/L for Galaxolide (HHCB) and 158 ± 89 ng/L for musk ketone respectively. Maximum secondary effluent concentrations were 2,000 ± 686 ng/L for HHCB and 51 ± 14 ng/L for musk ketone. Temperature appeared to influence the degree of removal of musks from wastewater during primary clarification (40% median removal at warm temperatures and 9% at cold temperatures) and overall treatment (82% median removal at warm temperatures and 74% at cold temperatures) but not secondary activated sludge treatment (71% median removal at warm temperatures and 70% at cold temperatures). In primary sludge, polycyclic musks were found at concentrations up to 35,000 ng/g for HHCB, and nitro musks were found at concentrations up to 490 ng/g for musk ketone. In waste activated sludge, polycyclic musks were found at concentrations up to 52,000 ng/g (HHCB), and nitro musks were found at concentrations up to 1,100 ng/g (musk ketone). The hydraulic retention time and the suspended solids of the treatment process appeared to influence the degree of partitioning of musks to sludge.
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Rimkus, Gerhard G. « Polycyclic musk fragrances in the aquatic environment ». Toxicology Letters 111, no 1-2 (décembre 1999) : 37–56. http://dx.doi.org/10.1016/s0378-4274(99)00191-5.
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Sapozhnikova, Yelena, Dan Liebert, Edward Wirth et Michael Fulton. « POLYCYCLIC MUSK FRAGRANCES IN SEDIMENTS AND SHRIMP TISSUES ». Polycyclic Aromatic Compounds 30, no 5 (octobre 2010) : 298–308. http://dx.doi.org/10.1080/10406638.2010.525160.
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Schwartz, Stefan, Volker Berding et Michael Matthies. « Aquatic fate assessment of the polycyclic musk fragrance HHCB ». Chemosphere 41, no 5 (septembre 2000) : 671–79. http://dx.doi.org/10.1016/s0045-6535(99)00510-x.
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Fromme, Hermann, Thomas Otto et Konstanze Pilz. « Polycyclic musk fragrances in different environmental compartments in Berlin (Germany) ». Water Research 35, no 1 (janvier 2001) : 121–28. http://dx.doi.org/10.1016/s0043-1354(00)00233-5.
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Mersch-Sundermann, V., S. Kevekordes et C. Jenter. « Lack of Mutagenicity of Polycyclic Musk Fragrances in Salmonella typhimurium ». Toxicology in Vitro 12, no 4 (août 1998) : 389–93. http://dx.doi.org/10.1016/s0887-2333(98)00007-1.
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Rimkus, Gerhard G., et Manfred Wolf. « Polycyclic musk fragrances in human adipose tissue and human milk ». Chemosphere 33, no 10 (novembre 1996) : 2033–43. http://dx.doi.org/10.1016/0045-6535(96)00321-9.
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Fromme, H., T. Otto et K. Pilz. « Polycyclic musk fragrances in fish samples from Berlin waterways, Germany ». Food Additives and Contaminants 18, no 11 (novembre 2001) : 937–44. http://dx.doi.org/10.1080/02652030110063579.
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Lee, Hing-Biu, Thomas E. Peart et Kurtis Sarafin. « Occurrence of Polycyclic and Nitro Musk Compounds in Canadian Sludge and Wastewater Samples ». Water Quality Research Journal 38, no 4 (1 novembre 2003) : 683–702. http://dx.doi.org/10.2166/wqrj.2003.043.
Texte intégralRésumé :
Abstract Fragrances such as synthetic musk compounds are commonly used as additives in a wide range of consumer and personal-care products. At the end of their life cycle, most of these compounds will end up in municipal sewage systems. In this work, we report the occurrence of selected polycyclic and nitro musk compounds in sewage sludge, influent, effluent, as well as some industrial wastewater samples collected in Canada. A newly developed supercritical carbon dioxide extraction technique was used for the extraction of residual musk fragrances in the sludge. Final analysis was performed by gas chromatography/ mass spectrometry (GC/MS) using electron-impact and methane negative ion chemical ionization techniques. The results indicated that Galaxolide® (HHCB), Tonalide® (AHTN), musk xylene (MX), and musk ketone (MK) were the most common musk compounds in the Canadian environment, as they were found in every sample in this study. In the same sludge sample, levels of HHCB and AHTN (ranging from 1.3 to 26.7 μg/g) were often found to be about 1000 times higher than those of MX and MK (ranging from 1.4 to 422 ng/g). Similarly, in the sewage influent and effluent collected in Ontario, the levels of HHCB and AHTN (ranging from 159 to 2411 ng/L) were much higher than those of MX and MK (ranging from 1 to 84 ng/L). The levels of musk compounds varied widely in industrial wastewaters. In one sample collected from a detergent manufacturer, the levels of HHCB, AHTN, MX, and MK were found to be 54,200, 13,300, 5480, and 2.2 ng/L, respectively. It was also noted that the levels of MX and MK observed in the samples collected from the commercial laundries in Toronto were significantly higher than those found in domestic sewage.
Thèses sur le sujet "Polycyclic musk"
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Ward, Collin P. « Direct and Indirect Photochemical Degradation of Two Polycyclic Musk Fragrances and Two Polycyclic Aromatic Hydrocarbons in Natural Waters ». The Ohio State University, 2010. http://rave.ohiolink.edu/etdc/view?acc_num=osu1275577426.
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TASSELLI, STEFANO. « Innovative techniques for the removal of organic micropollutants from wastewaters ». Doctoral thesis, Università degli Studi di Milano-Bicocca, 2021. http://hdl.handle.net/10281/305578.
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I prodotti per la cura personale sono un gruppo eterogeneo di sostanze chimiche che includono le fragranze sintetiche (PMF) come Galaxolide (HHCB), Tonalide (AHTN), Celestolide (ADBI) e Phantolide (AHDI). I PMF sono molto utilizzati nei profumi, detergenti e nei prodotti per la pulizia della casa e ciò porta al loro rilascio nell'ambiente per lo più attraverso gli scarichi degli impianti di depurazione. Anche se l'Italia è il paese europeo con il più alto utilizzo di PMF, pochi dati sono disponibili sulla loro presenza nelle acque italiane e sul loro destino negli impianti convenzionali. In tale contesto, questa ricerca si è concentrata in primo luogo sullo sviluppo di nuovi protocolli per la determinazione dei PMF nelle acque reflue e nei fanghi attivi. I PMF nei campioni di acqua sono stati estratti mediante SPE e analisi in GC-MS con triplo quadrupolo mentre i fanghi attivi sono stati analizzati usando un bagno ad ultrasuoni e una trappola ionica. I limiti di rilevabilità ottenuti sono stati molto inferiori alle concentrazioni dei campioni. Questi metodi consentono l'analisi di molti campioni in tempi brevi impiegando strumentazione semplice e limitando i volumi di solvente utilizzati. Sono stati poi monitorati i PMF all'interno di un depuratore convenzionale italiano. HHCB e il suo principale sottoprodotto, il Galaxolidone (HHCB-lattone), sono stati trovati in concentrazioni di µg/L, un ordine di grandezza maggiore di AHTN, mentre ADBI è stato rilevato in tracce e AHDI era semprePersonal care products are a heterogeneous group of chemicals that include Polycyclic Musk Fragrances (PMFs) as Galaxolide (HHCB), Tonalide (AHTN), Celestolide (ADBI) and Phantolide (AHDI). PMFs are widely spread substances employed in perfumes, detergents and house-cleaning products. The massive use leads to PMF release into the environment mainly through Wastewater Treatment Plants (WWTPs) discharges. Even if Italy is the European country with the highest use of PMFs, only a few data are available about these products’ occurrence in Italian water and about PMF fate in conventional WWTPs. In this, PhD was firstly focused on developing protocols for PMF determination in wastewater and in activated sludge. PMFs in water samples were determined by SPE extraction and analysis in GC-MS with a triple-quadrupole while for the analysis of activated sludge an ultrasonic bath and a GC-Ion trap were employed. Detection limits of selected compounds were considerably lower than sample concentrations. These methods allow the analysis of many samples in short times employing simple instrumentation and limiting the solvent volumes used. After that, PMFs inside an Italian conventional WWTPs was monitored. HHCB and its main by-product, Galaxolidone (HHCB-lactone), were found in concentrations of µg/L, one order of magnitude greater than AHTN, AHDI was always lower than LOD while ADBI was measured only at trace levels. No seasonal variability was recorded in PMF input onto WWTP. In the water phase, HHCB and AHTN evidenced a modest reduction during treatments (20% and 50%, respectively) mainly due to adsorption processes during the biological treatment as suggested by the high stable PMF concentrations in activated sludges. HHCB-lactone registered an increase up to 70% during treatments caused by HHCB biotransformation during biological treatment. This study revealed that current technologies are not enough efficient in removing PMFs from wastewaters which are discharged into the environment. Additional treatments are therefore necessary inside WWTPs. In this, the efficiency of ozonation and adsorption on activated carbon in removing PMFs from wastewaters was assessed. Treatments were tested through two pilot plants installed after the biological treatment in two WWTPs located in Northern Italy. Different conditions were tested to achieve the best compromise between removal efficiencies and management costs. Regarding ozonation, a medium-low dosage of O3 was applied. HHCB was efficiently removed at low O3 dosages and short hydraulic retention times while AHTN and HHCB-lactone were less reactive to oxidation. HHCB-lactone registered insufficient removals even with the highest O3 dosage and hydraulic retention time. Ozonation was effective in removing PMFs from wastewater but high gas dosages may be required to avoid the formation of oxidation by-products. Adsorption on powdered activated carbon (PAC) was tested in a pilot plant consisting on a series of tanks in which PAC is added to the wastewater together with coagulant, microsand and flocculant and can be further recirculated. By operating on water flow, quantity of virgin PAC added to the system and concentration of PAC inside the pilot plant, different setups were studied and satisfactory removals were achieved for all studied compounds even at low concentrations of the two PACs. A dependence between PMF removal efficiency and PAC concentration, quantity of virgin PAC and hydraulic flow rate was highlighted. In our pilot plant, lower dosages of carbon can be further tested in order to obtain high removals together with lower management costs. By comparing two different PACs, the importance of associating the PAC type with the class of compound to remove was highlighted. Overall, both technologies were effective in removing PMFs from wastewaters even if adjustment of operational parameters is needed to obtain great performances with low operating costs.
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Jacobs, Elizabeth Mara. « Identification and Quantification of Polycyclic Musks and Methyl-Triclosan in Unknown Freshwater Fish Tissue Samples ». W&M ScholarWorks, 2009. https://scholarworks.wm.edu/etd/1539626893.
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Giansiracusa, Sara. « Bioaccumulation of legacy and emerging contaminants in tuna species ». Master's thesis, Alma Mater Studiorum - Università di Bologna, 2019. http://amslaurea.unibo.it/18305/.
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Environmental contamination of legacy contaminants has been of great concern worldwide because of their persistence and toxicity to humans and marine species. Only in the last decade, the presence and accumulation of emerging contaminants, and, consequently, their adverse effects in marine biota have been considered. The present research was performed to compare the different distribution of legacy contaminants (Pesticides, PCBs and PAHs) and emerging contaminants (UV filters and Fragrances) in the liver and muscle tissues of three tuna species living in different locations and with different behaviour and feed habits: Sarda sarda, Katsuwonus pelamis from the Atlantic Ocean (Gulf of Càdiz) and Thunnus thynnus from the Strait of Gibraltar. The extraction and quantitative determination of these contaminants from liver and muscle samples have been carried out by Accelerate Solvent Extraction and GC-MS/MS techniques, respectively. From the statistical analysis, significant differences have been found for Fragrances, Pesticides, PCBs and PAHs both among the three tuna species and between the two tissues. Post-hoc analysis showed significant differences between the three tuna species and the tissues, revealing that K. pelamis species differs significantly from the other two species, both in liver and muscle, and that legacy contaminants are responsible for significant differences between and within species. We also explored the similarities between concentrations of PCBs and DDTs in liver and muscle tissue found in samples of T. thynnus and K. pelamis in this study, compared to concentrations of PCBs and DDTs found in specimens of tuna collected in different geographical areas. As a result of the continuous exposure of the marine top predators, such as tuna species, to variable concentrations of emerging and legacy contaminants, their concentration in the marine environment must be constantly monitored.
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Wang, Yu-Chen, et 王妤甄. « Determination of Synthetic Polycyclic Musk in Aqueous Samples by Microwave-Assisted HS-SPME & ; GC/MS ». Thesis, 2009. http://ndltd.ncl.edu.tw/handle/75039727805755011937.
Texte intégralRésumé :
碩士國立中央大學
化學研究所
97
Synthetic musk fragrances are a group of chemicals used widely in detergents, perfumes, shampoos, and many other personal care products. According to their physical and chemical properties, they are in common with many hydrophobic and semivolatile organic pollutants that are known to biomagnify through the food chain. The occurrence of synthetic polycyclic musks, a group of the most concern synthetic musk fragrances currently, has been reported in air, freshwater, seawater and sediment suggesting that they are widespread contaminants in the environment. Because of their highly lipophilic properties, polycyclic musks have been also found in aquatic biota, such as mussels and fish, and even in human adipose tissue and breast milk. These compounds have been shown to demonstrate estrogenic activities, even higher concentrations of synthetic polycyclic musks in women''s bloods have been correlated to higher rate of miscarriage. In this study, the sample pretreatment technique of microwave-assisted headspace solid-phase microextraction (MA-HS-SPME) has been developed and studied for the extraction of six commonly used synthetic polycyclic musks (i.e., Galaxolide (HHCB), Tonalide (AHTN), Celestolide (ADBI), Traseolide (ATII), Cashmeran (DPMI) and Phantolide (AHMI)) in aqueous samples prior to gas chromatography-mass spectrometry (GC-MS) analysis. The effects of various extraction parameters (i.e., extraction time, microwave power and addition of salt) for the quantitative extraction of these polycyclic musks by MA-HS-SPME were systematically investigated and optimized. The analytes can be extracted by 65 ?m PDMS/DVB fiber under 180 W microwave power for 4 min, 20 mL water sample added 4 g NaCl was put in 40 mL vial with headspace 20 mL (the ratio of sample : headspace = 1:1, v/v). The limit of detection (LOD) ranged from 0.05 to 0.1 ng/L and the limit of quantification (LOQ) was less than 0.2 ng/L. Preliminary results show that HHCB and AHTN were two commonly detected polycyclic musks in real environmental samples, ranging from 1.2 to 37.3 ng/L via standard addition method with correlation coefficient (r2) above 0.981. The analytical procedure developed herein demonstrated that the MA-HS-SPME and GC-MS-SIM methods are reliable, sensitive and offer a convenient analytical technique for trace determination of polycyclic musks in various water samples.
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Naspinski, Christine S. « Toxicity Analysis of Polycyclic Aromatic Hydrocarbon Mixtures ». 2009. http://hdl.handle.net/1969.1/ETD-TAMU-2009-05-310.
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Polycyclic aromatic hydrocarbons (PAHs) are widely distributed in the
environment and are generated by many sources. Though the potential of PAH-rich
mixtures to cause health effects has been known for almost a century, there are still
unanswered questions about the levels of PAHs in the environment, the potential for
human exposure to PAHs, the health effects associated with exposure, and how genetic
susceptibility influences the extent of health effects in individuals.
The first objective of this research was to quantify concentrations of PAHs in
samples of settled house dust collected from homes in Azerbaijan, China, and Texas.
The trends of PAH surface loadings and percentage of carcinogenic PAHs were China
> Azerbaijan > Texas, indicating that the risk of health effects from exposure to PAHs in
house dust is highest in the Chinese population and lowest in the Texas population.
PAHs in China and Azerbaijan were derived mainly from combustion sources; Texas
PAHs were derived from unburned fossil fuels such as petroleum.
The second objective of this research was to investigate the effect of pregnane
X receptor (PXR) on the genotoxicity of benzo[a]pyrene (BaP). BaP treatment resulted
in significantly lower DNA adduct levels in PXR-transfected HepG2 cells than in
parental HepG2 cells. Total GST enzymatic activity and mRNA levels of several
metabolizing enyzmes were significantly higher in cells overexpressing PXR. These
results suggest that PXR protects cells against DNA damage by PAHs such as BaP,
possibly through a coordinated regulation of genes involved in xenobiotic metabolism.
The third objective of this research was to investigate biomarkers of exposure in
house mice (Mus musculus) exposed to PAH mixtures in situ. Mice and soil were
collected near homes in Sumgayit and Khizi, Azerbaijan. Mean liver adduct levels were
significantly higher in Khizi than in Sumgayit. Mean lung and kidney adduct levels were similar in the two regions. The DNA lesions detected may be a combination of
environmentally-induced DNA adducts and naturally-occurring I-compounds. PAHs
were present at background levels in soils from both Khizi and Sumgayit. It appears
that health risks posed to rodents by soil-borne PAHs are low in these two areas.
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Wu, Shin-Fang, et 吳欣芳. « Fast Determination of Synthetic Polycyclic Musks in Solid Samples by Solvent Free Techniques ». Thesis, 2010. http://ndltd.ncl.edu.tw/handle/10781221893366054387.
Texte intégralRésumé :
碩士國立中央大學
化學研究所
98
Fragrances have been used increase attractiveness of persons since ancienttimes. Musk is one of the most important and often used fragrances in perfumery. Synthetic polycyclic musks are inexpensive substitutes for natural musks. Synthetic polycyclic musk compounds enter environment principally through effluents of wastewater treatment plants and waste sludge, and the major source of environmental pollution of synthetic musks is from sewage. In this study, one-step in situ microwave-assisted headspace solid-phase microextraction (MA-HS-SPME) followed by gas chromatography-mass spectrometry (GC-MS) analysis is presented as a fast and solvent-free technique to determine synthetic polycyclic musks in sewage sludge, sediment and oyster samples. The dewatered solid sample mixed with 20-mL deionized water was efficiently extracted by a polydimethylsiloxane-divinylbenzene (PDMS-DVB) fiber placed in the headspace when the extraction slurry was microwave irradiated at 80 W for 5 min. The limits of detection (LODs) ranged from 0.04 to 0.1 ng/g, and the limits of quantification (LOQs) ranged from 0.1 to 0.3 ng/g (fresh weight). A preliminary analysis of those samples revealed that HHCB and AHTN were the two most commonly detected synthetic polycyclic musks; using a standard addition method, their total concentrations were determined to rangefrom 0.3 to 10.9 ng/g (fresh weight) with relative standard deviation (RSD)ranging from 4% to 10%. The analytical procedure developed demonstrated that the MA-HS-SPME and GC-MS-SIM methods are reliable, sensitive and offer a convenient analytical technique for trace determination of polycyclic musks in various solid samples in environment.
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Chen, Shiang-Ting, et 陳相廷. « Effects of polycyclic musks and bisphenol A on the settlement and metamorphosis on sponge, Spongia ceylonensis ». Thesis, 2011. http://ndltd.ncl.edu.tw/handle/57825056322457055974.
Texte intégralRésumé :
碩士國立中山大學
海洋生物研究所
100
Sponge population partly depends on larval recruitment. Environmental factors, e.g. light, salinity, pH and temperature, chemical factors and pollution may influence larval settlement and metamorphosis. In this study, the effects of galaxolide（HHCB）、tonalide（AHTN）and bisphenol A（BPA）on the settlement and metamorphosis of an intertidal sponge （Spongia ceylonensis） were examined. The experiments included LC50 test, effects of solvent, HHCB, AHTN and BPA on sponge settlement and metamorphosis. In the LC50 tests, the 96 hr–LC50 value of HHCB and AHTN all greater than 1.00 mg/L, and the 96 hr–LC50 of BPA was 0.58 mg/L. Acetone concentration (1.00 mg/L ) in this study didn’t affect sponge settlement and metamorphosis. Effect of HHCB and AHTN on sponge settlement and metamorphosis concentrations of 0.13, 0.25, 0.50 and 1.00 mg/L was insignificant. In contrast, the settlement rate was decrease by 20 % at treatment of 1.00 mg/L BPA. The metamorphosis rates were also decrease by 20 % and 80 % at concentrations of 0.50 mg/L and 1.00 mg/L BPA. In conclusion, the toxicity of AHTN was greater than that of HHCB to sponge settlement and metamorphosis.
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Yang, Ching-ya, et 楊清雅. « Ultrasound-assisted dispersive liquid-liquid microextraction for the rapid determination of synthetic polycyclic musks in aqueous samples ». Thesis, 2011. http://ndltd.ncl.edu.tw/handle/29755130701131347181.
Texte intégralRésumé :
碩士國立中央大學
化學研究所
99
Currently, a group of widely used synthetic musk fragrances, synthetic polycyclic musks have been detected in air, freshwater, seawater and sediment samples. Because of their highly lipophilic properties, polycyclic musks have been also found in aquatic biota, such as mussels and fish, and even in human adipose tissue and breast milk. These compounds have demonstrated estrogenic activity, even higher concentrations of synthetic polycyclic musks in women''s bloods have been correlated to higher rate of miscarriage. In this study, a simple and solvent-less procedure was developed for the determination of six commonly found synthetic polycyclic musks in aqueous samples using ultrasound-assisted dispersive liquid-liquid microextraction (UA-DLLME) coupled gas chromatography-mass spectrometry (GC-MS). The parameters affecting the extraction efficiency of analytes from water samples were systematically investigated and the conditions optimized. The best extraction conditions involved the rapid injection of a mixture of 1.0 mL of isopropyl alcohol (as a dispersant) and 10 μL of carbon tetrachloride (as an extractant) into 10 mL of water containing 0.5 g of sodium chloride in a conical bottom glass tube. After ultrasonication for 1.0 min and centrifugation at 5000 rpm (10 min), the sedimented phase 1.0 μL was directly injected into the GC-MS system. The limits of quantitation (LOQs) were less than 0.5 ng/L. The precision for these analytes, as indicated by relative standard deviations (RSDs), were less than 13% for both intra- and inter-day analysis. Accuracy, expressed as the mean extraction recovery, was between 62 and 104%. Using a standard addition method, their total concentrations were determined to be in the range from 8.3 to 63.9 ng/L in various environmental samples. The developed technique appears to be a good alternative extraction method for the determination of organic compounds in environmental water samples in that it is a simple, low cost, effective, and eco-friendly analytical method.
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Bandowe, Benjamin Acham Musa [Verfasser]. « Oxygen-containing polycyclic aromatic hydrocarbons (OPAHs) and their parent-PAHs in soil : analysis, sources and fate / Benjamin Acham Musa Bandowe ». 2010. http://d-nb.info/1005345562/34.
Texte intégralChapitres de livres sur le sujet "Polycyclic musk"
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Fromme, Hermann, Thomas Otto et Konstanze Pilz. « Polycyclic Musk Fragrances in the Aquatic Environment ». Dans ACS Symposium Series, 203–22. Washington, DC : American Chemical Society, 2000. http://dx.doi.org/10.1021/bk-2001-0773.ch015.
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Nicolai, Marisa, Paula Pereira et Lídia Palma. « The Influence of Some Contaminants in Food Quality ». Dans Mycotoxins and Food Safety - Recent Advances [Working Title]. IntechOpen, 2022. http://dx.doi.org/10.5772/intechopen.102911.
Texte intégralRésumé :
The concept of food quality has been following scientific and technological evolution. Currently, producers, users, consumers, as well as public authorities, have well defined their expectations regarding the quality requirements in the food sector. These projections are related to several parameters that are no longer seen only from a safety and nutritional point of view. Thus, the characteristics of food products must fulfill criteria that embrace their origin, esthetics, convenience, functionality, ethics, organoleptic and must result in benefit. The needs of consumers increasingly reflect public interests, which are supervised by public authorities that hold technical and scientific information that allows them to advocate normative regulations regarding defects, adulteration, and fraud, increasing awareness in the food quality field. Since food quality and safety are two increasingly interconnected domains, the different EU legislation and regulations impose procedures for the determination of contaminants. In this chapter, we will only cover three main topics, namely heavy metals, polycyclic aromatic hydrocarbons, and mycotoxins.
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Manzo-Sánchez, Gilberto, Marco Tulio Buenrostro-Nava, Carlos L. Leopardi, Mario Orozco-Santos et Mauricio Guzman-Quesada. « Genetic Diversity of Fusarium Wilt Disease of Banana ». Dans Genetic Diversity [Working Title]. IntechOpen, 2020. http://dx.doi.org/10.5772/intechopen.94158.
Texte intégralRésumé :
Bananas and plantains (Musa spp.) represent the fourth most important crop in the world. In 2017, an area of 5,637,508 hectares and a production of 153 million tons were reported. Fusarium wilt caused by the fungus Fusarium oxysporum f. sp. cubense (Foc), is considered one of the most destructive diseases of bananas and plantains worldwide. The pathogen Foc causes a typical wilt syndrome on infected plants, it has a saprophytic and parasitic phase in its life cycle. Fusarium wilt is a “polycyclic” disease. This pathogen shows a relatively diverse population genetic structure for a fungus apparently of asexual reproduction and is composed of different evolutionary lineages, which has 24 groups of vegetative compatibility (VCGs), two clades and nine clonal linage. Foc is a genetically diverse pathogen, although the available evidence so far indicates that it does not use the mechanisms of sexual reproduction, such as recombination, to increase its genetic diversity. Furthermore, the population of this fungus in Southeast Asia shows a high degree of variation, suggesting that Foc lineages evolved together with their hosts in Southeast Asia. Alternatively, it has been suggested that Foc has multiple independent evolutionary origins, both within and outside of the Musaceae origin center.
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Calvert, Jack G., John J. Orlando, William R. Stockwell et Timothy J. Wallington. « Photodecomposition of Light-Absorbing Oxygenates and Its Influence on Ozone Levels in the Atmosphere ». Dans The Mechanisms of Reactions Influencing Atmospheric Ozone. Oxford University Press, 2015. http://dx.doi.org/10.1093/oso/9780190233020.003.0011.
Texte intégralRésumé :
Photochemistry provides the important driving force that initiates chemistry in the atmosphere. We saw in Chapter II how light absorbed by ozone generates the important HO radical, and, in Chapter III, we reviewed how light absorption by NO2 leads to ozone formation. In this chapter, we discuss the photochemistry of the light-absorbing oxygenates: their photochemical lifetimes and the nature of the modes of photodecomposition they undergo. Of course, light of sufficient energy per quantum must be absorbed by a molecule if its photodecomposition is to occur. The hydrocarbons do not absorb tropospheric sunlight, as seen in Figure VIII-A-1. The light gray and dark gray lines, respectively, show the distribution of actinic flux present in the troposphere and upper stratosphere for overhead Sun. It can be seen that the larger alkanes, alkenes, and aromatic hydrocarbons absorb at somewhat longer wavelengths than the first member of the family, but none can be electronically excited by tropospheric radiation. Among the hydrocarbons, only the polycyclic aromatics absorb appreciable tropospheric sunlight, and their π → π* excitation does not result in decomposition but likely generates O2(1Δg) molecules by energy transfer; these molecules are usually quenched by collision to ground state O2(3Σg−) molecules (see Calvert et al., 2000). As atmospheric oxidation of the hydrocarbons occurs, initiated largely by HO radicals, a multitude of oxygenated organic species are generated. The absorption region for the oxygenates is generally shifted to longer wavelengths, although the alcohols, ethers, acids, and esters still show no overlap of the regions of tropospheric actinic flux. For the families of compounds shown, the only significant absorbers of tropospheric sunlight are the aldehydes (e.g., CH2O) and the ketones (e.g., CH3C(O)CH3). Formic acid and methyl formate, as well as the larger members of the acid and ester families, absorb sunlight available only at the higher altitudes of the stratosphere, where they are expected to photodecompose. However, these species are not expected to be present in the stratosphere because they are removed in the troposphere largely via HO reactions. In this chapter, we focus on the rates and pathways for photodecomposition of the aldehydes and ketones with less detailed considerations of the other less prevalent light-absorbing trace compounds.
5
« Hudson River Fishes and their Environment ». Dans Hudson River Fishes and their Environment, sous la direction de Isaac Wirgin et R. Christopher Chambers. American Fisheries Society, 2006. http://dx.doi.org/10.47886/9781888569827.ch19.
Texte intégralRésumé :
<em>Abstract.</em>—Despite recent successes in eliminating or reducing many point sources of chemical contaminants, sediments in the Hudson River Estuary are still highly contaminated with lipophilic and highly persistent polychlorinated biphenyls (PCBs), polychlorinated dibenzo-<em>p</em>-dioxins (PCDDs), polychlorinated dibenzofurans (PCDFs), and polycyclic aromatic hydrocarbons (PAHs). These have been shown to bioaccumulate to high levels in resource species and other key ecological components of the Hudson River food web. Resource managers and stewards must consider the possible toxic effects of these pollutants on the Hudson River biota, including its fish community; however, few studies have directly investigated these effects. A series of toxicological studies on Atlantic tomcod <em>Microgadus tomcod </em>from the Hudson River Estuary have demonstrated profound and broad-based changes in response to local contaminants. Levels of contaminants in the tissues of different life stages of tomcod from the Hudson River Estuary far exceed those in tomcod from other Atlantic Coast estuaries. More importantly, a combination of field and laboratory studies has demonstrated molecular to population level perturbations in tomcod from the Hudson River, all of which are consistent with chemical exposures and many of which appear to be mechanistically linked. These effects include induction of hepatic expression of cytochrome P4501A1 mRNA, high levels of hepatic DNA damage, somatic mutations at an oncogene locus critical to the initiation of chemical carcinogenesis, elevated prevalence of gross and histologically defined hepatic tumors, truncated age structure, and dramatic resistance at the molecular and organismal levels to halogenated aromatic hydrocarbons (HAHs). Resistance, a population level effect, was observed in the toxic responses of tomcod embryos and larvae to 2,3,7,8-tetrachlorodibenzo-<em>p</em>-dioxin (TCDD) and TCDD-like PCBs, but not PAHs. Because young of the year tomcod are a critical node in the Hudson River food chain, their evolved resistance to HAHs and high body burden of these and related contaminants has likely resulted in the trophic transfer of these contaminants to secondary and tertiary consumers of the Hudson River, including important resource species, and an elevated tissue burden of these contaminants in those consumers. In total, these studies are consistent with the hypothesis that exposure to Hudson River-borne contaminants has significantly altered its tomcod population and perhaps evoked broad change in the Hudson River fish community.
6
« Hudson River Fishes and their Environment ». Dans Hudson River Fishes and their Environment, sous la direction de Isaac Wirgin et R. Christopher Chambers. American Fisheries Society, 2006. http://dx.doi.org/10.47886/9781888569827.ch19.
Texte intégralRésumé :
<em>Abstract.</em>—Despite recent successes in eliminating or reducing many point sources of chemical contaminants, sediments in the Hudson River Estuary are still highly contaminated with lipophilic and highly persistent polychlorinated biphenyls (PCBs), polychlorinated dibenzo-<em>p</em>-dioxins (PCDDs), polychlorinated dibenzofurans (PCDFs), and polycyclic aromatic hydrocarbons (PAHs). These have been shown to bioaccumulate to high levels in resource species and other key ecological components of the Hudson River food web. Resource managers and stewards must consider the possible toxic effects of these pollutants on the Hudson River biota, including its fish community; however, few studies have directly investigated these effects. A series of toxicological studies on Atlantic tomcod <em>Microgadus tomcod </em>from the Hudson River Estuary have demonstrated profound and broad-based changes in response to local contaminants. Levels of contaminants in the tissues of different life stages of tomcod from the Hudson River Estuary far exceed those in tomcod from other Atlantic Coast estuaries. More importantly, a combination of field and laboratory studies has demonstrated molecular to population level perturbations in tomcod from the Hudson River, all of which are consistent with chemical exposures and many of which appear to be mechanistically linked. These effects include induction of hepatic expression of cytochrome P4501A1 mRNA, high levels of hepatic DNA damage, somatic mutations at an oncogene locus critical to the initiation of chemical carcinogenesis, elevated prevalence of gross and histologically defined hepatic tumors, truncated age structure, and dramatic resistance at the molecular and organismal levels to halogenated aromatic hydrocarbons (HAHs). Resistance, a population level effect, was observed in the toxic responses of tomcod embryos and larvae to 2,3,7,8-tetrachlorodibenzo-<em>p</em>-dioxin (TCDD) and TCDD-like PCBs, but not PAHs. Because young of the year tomcod are a critical node in the Hudson River food chain, their evolved resistance to HAHs and high body burden of these and related contaminants has likely resulted in the trophic transfer of these contaminants to secondary and tertiary consumers of the Hudson River, including important resource species, and an elevated tissue burden of these contaminants in those consumers. In total, these studies are consistent with the hypothesis that exposure to Hudson River-borne contaminants has significantly altered its tomcod population and perhaps evoked broad change in the Hudson River fish community.
Actes de conférences sur le sujet "Polycyclic musk"
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Zhao, Xiaoguang, Dili Sun, Shijie Song, Linting Guo et Chuanke Shao. « The glutathione content variation in earthworms exposed to polycyclic musks ». Dans International Conference on Civil, Transportation and Environmental Engineering (CTEE 12). Southampton, UK : WIT Press, 2013. http://dx.doi.org/10.2495/ctee120651.
Texte intégral
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Ramirez Hernandez, Astrid, Trupti Kathrotia, Torsten Methling, Marina Braun-Unkhoff et Uwe Riedel. « An Upgraded Chemical Kinetic Mechanism for ISO-Octane Oxidation : Prediction of Polyaromatics Formation in Laminar Counterflow Diffusion Flames ». Dans ASME Turbo Expo 2022 : Turbomachinery Technical Conference and Exposition. American Society of Mechanical Engineers, 2022. http://dx.doi.org/10.1115/gt2022-83053.
Texte intégralRésumé :
Abstract Iso-octane is widely recognized as a prominent candidate to represent the oxidation of iso-alkanes within jet fuel and gasoline surrogates. This work evaluated a chemical kinetic mechanism for iso-octane focusing on the model’s capability to predict the formation of polycyclic aromatic hydrocarbons (PAHs). As the model is intended to be further coupled with soot models, the chemical kinetic mechanism must supply good predictability of the formation and consumption of PAHs considered as major soot precursors. A first validation of the iso-octane sub-model as incorporated within ESTiMatE-Mech, using experimental data from literature, reveals the need to improve the sub-model. Considerable deviations were observed in the prediction of the PAHs, although concentration profiles of major species and fundamental combustion properties such as ignition delay time and laminar flame speed were accurately predicted. Through rate of production and sensitivity analyses of the mechanism, nine reactions were identified to have a strong influence in the (over)prediction of the PAHs. These reactions have been modified based on information gathered from literature resulting in an updated version of the mechanism called ESTiMatE-Mech_mod. Simulation results with this modified mechanism showed that this updated mechanism is now capable of predicting well the targeted PAHs, while retaining the good initial prediction of the major species concentration profiles as well as of laminar flame speeds and ignition delay times.