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Resultados 1-10 de 20
Uptake of ozone and modification of lipids in Betula Pendula pollen
2018
Zhu, Chao | Farah, Jinane | Choël, Marie | Gosselin, Sylvie | Baroudi, Moomen | Petitprez, Denis | Visez, Nicolas
Pollen allergy risk is modified by air pollutants, including ozone, but the chemical modifications induced on pollen grains are poorly understood. Pollen lipidic extract has been shown to act as an adjuvant to the allergenic reaction and therefore, the modification of lipids by air pollutants could have health implications. Birch pollen was exposed in vitro to ozone to explore the reactivity of O₃ on its surface and on its lipidic fraction. Uptake coefficients of ozone were determined for ozone concentration of 117 ppb on the surface of native birch pollen (8.6 ± 0.8 × 10⁻⁶), defatted pollen (9.9 ± 0.9 × 10⁻⁶), and for crushed pollen grains (34±3 × 10⁻⁶). The mass of ozone uptaken was increased by a factor of four for crushed pollen compared to native pollen showing a higher susceptibility to ozone of cytoplasmic granules and broken pollen grains. A total mass of extractible lipids of 27 mg per gram of birch pollen was found and a fraction of these lipids was identified and quantified (fatty acids, alkanes, alkenes and aldehydes). The distribution of lipids was modified by ozone exposure of 115 and 1000 ppb for 16 h with the following reactivity: consumption of alkene, formation of aldehydes and formation of nonanoic acid and octadecanoic acid. The quantity of ozone trapped in the lipidic fraction during 15 min at 115 ppb is enough to contribute to the reactivity of one-third of the alkenes demonstrating that pollen could be susceptible to an atmospheric increase of ozone concentration even for a very short duration complicating the understanding of the link between pollen allergy and pollution.
Mostrar más [+] Menos [-]Release and fate of nanoparticulate TiO2 UV filters from sunscreen: Effects of particle coating and formulation type
2021
Slomberg, Danielle L. | Catalano, Riccardo | Bartolomei, Vincent | Labille, Jérôme
Nanoparticulate mineral UV filters, such as titanium dioxide (TiO₂) nanocomposites, are being increasingly used in sunscreens as an alternative to organic UV filters. However, there is still a lack of understanding regarding their fate and behavior in aquatic environments and potential environmental impacts after being released from a bather’s skin during recreational activities. In this work, we assessed the release, fate, and transformation of two commercial nanocomposite TiO₂ UV filters, one hydrophobic and one hydrophilic, in ultrapure water and simulated fresh- and seawater. The hydrophobic TiO₂ nanocomposite, T-SA, was coated with a primary Al₂O₃ photopassivation layer and a secondary stearic acid layer, while the hydrophilic TiO₂ nanocomposite, T-SiO₂, was coated with a single SiO₂ photopassivation layer. The influence of the sunscreen formulation was examined by dispersing the TiO₂ nanocomposites in their typical continuous phase (i.e., oil for T-SA and water for T-SiO₂) before introduction into the aqueous system. After 48 h of aqueous aging and 48 h of settling, 88–99% of the hydrophobic T-SA remained floating on top of the water column in all aqueous systems. On the other hand, 100% of the hydrophilic T-SiO₂ settled out of the water column in the fresh- and seawaters. With respect to the photopassivation coatings, no loss of the T-SA Al₂O₃ layer was detected after aqueous aging, but 99–100% dissolution of the SiO₂ layer on the T-SiO₂ nanocomposite was observed after 48 h in the fresh- and seawaters. This dissolution left behind T-SiO₂ by-products exhibiting a photocatalytic activity similar to that of bare rutile TiO₂. Overall, the results demonstrated that the TiO₂ surface coating and sunscreen formulation type drive environmental behavior and fate and that loss of the passivation layer can result in potentially harmful, photoactive by-products. These insights will help guide regulations and assist manufacturers in developing more environmentally safe sunscreens.
Mostrar más [+] Menos [-]Urinary concentrations of phthalates in relation to circulating fatty acid profile in National Health and Nutrition Examination Survey, 2003–2004 and 2011–2012
2020
Li, Ming-Chieh | Lin, Jingyu | Guo, Yue Leon
Animal studies have suggested that phthalate exposure alters the fatty acid composition of blood plasma. Therefore, we conducted an epidemiological study to examine whether urinary concentrations of phthalates are correlated with circulating fatty acids in the general US population. The 2003–2004 and 2011–2012 National Health and Nutrition Examination Survey were used in this study. Ten urinary phthalate metabolites and 23 fatty acids were measured. Fatty acid patterns were identified using principal component analysis (PCA) with an eigenvalue greater than 1. A two-step analysis was performed. We first performed multivariable linear regressions to evaluate whether urinary phthalate metabolites were related to the PCA-derived components of blood fatty acid levels. Then we performed multivariable linear regressions to investigate each of the fatty acids that were suggestively correlated with some of the phthalates in PCA. There were 994 participants (51.91% women). As for men, after adjustments for potential confounding factors, MECPP, MEHHP, and ∑DEHP were all positively correlated with gamma-linolenic, myristoleic, and myristic acids; both MEHHP and ∑DEHP were positively correlated with stearic acid; MMP was positively correlated with docosahexaenoic acid. As for women, MMP was negatively correlated with docosanoic, lignoceric, and arachidic acids; MBzP was negatively correlated with docosahexaenoic acid; both MEHP and MCPP were negatively correlated with docosatetraenoic acid; MEHP was negatively correlated with arachidonic acid, and MCPP was negatively correlated with docosapentaenoic-6 acid. Our findings support that phthalates may be correlated with circulating fatty acids.
Mostrar más [+] Menos [-]Stabilizing mixed fatty acid and phthalate ester monolayer on artificial seawater
2018
Li, Siyang | Du, Lin | Zhang, Qingzhu | Wang, Wenxing
Phthalate esters which are widely used as industrial chemicals have become widespread contaminants in the marine environment. However, little information is available on the interfacial behavior of phthalate esters in the seawater, where contaminants generally occur at elevated concentrations and have the potential to transfer into the atmosphere through wave breaking on sea surface. We used artificial seawater coated with fatty acids to simulate sea surface microlayer in a Langmuir trough. The interactions of saturated fatty acids (stearic acid (SA) and palmitic acid (PA)) with one of the most abundant phthalate esters (di-(2-ethylhexyl) phthalate (DEHP)), were investigated under artificial seawater and pure water conditions. Pure DEHP monolayer was not stable, while more stable mixed monolayers were formed by SA and DEHP on the artificial seawater at relatively low surface pressure. Sea salts in the subphase can lower the excess Gibbs free energy to form more stable mixed monolayer. Among the ten components in the sea salts, Ca²⁺ ions played the major role in condensation of mixed monolayer. The condensed characteristic of the mixed SA (or PA)/DEHP monolayers suggested that the hydrocarbon chains were ordered on artificial seawater. By means of infrared reflection-absorption spectroscopy (IRRAS), we found that multiple sea salt mixtures induced deprotonated forms of fatty acids at the air–water interface. Sea salts can improve the stability and lifetime of mixed fatty acid and phthalate ester monolayer on aqueous droplets in the atmosphere. Interfacial properties of mixed fatty acid and phthalate ester monolayers at the air–ocean interface are important to help understand their behavior and fate in the marine environment.
Mostrar más [+] Menos [-]A new record for the presence of microplastics in dominant fish species of the Karasu River Erzurum, Turkey
2022
Atamanalp, Muhammed | Köktürk, Mine | Parlak, Veysel | Ucar, Arzu | Arslan, Gökhan | Alak, Gonca
It is known that microplastics (MPs) are increasingly detected in aquatic environments (sea and fresh water), and the presence of these pollutants have worrying potential effects on the biota. This study is the first research to measure and characterize MPs in freshwater ecosystems (inland waters) in Turkey. Accordingly, the identification and characterization of MPs in the gastrointestinal systems of fish by making samples of three species [chub (Squalius cephalus), common carp (Cyprinus carpio), and mossul bleak (Alburnus mossulensis)] of the carp family living in Karasu River in Erzurum. Hydrogen peroxide application and Fourier transform infrared-attenuated total reflectance (ATR-FTIR) analyses were done for this purpose. In the obtained results, 232 microplastics were found in all three fish gastrointestinal systems. While the highest determined color was black (39–58%), the most common shape was fiber (88%), fragment (6%, and pellet (6%); MPs in the range of maximum 1001–2000 mm were detected in size. Plastics are defined as polyethylene, polyester, poly (vinyl stearate), polyethylene terephthalate, polypropylene, and cellulose. Among the studied species, the most common type of plastic pollutants was found in S. cephalus. The findings indicated the presence of microplastics in dominant species. However, these findings will be basic information for future studies on living things and microplastics in inland waters.
Mostrar más [+] Menos [-]Biodegradation kinetic modeling of pro-oxidant filled polypropylene composites under thermophilic composting conditions after abiotic treatment
2021
Sable, Sunil | Ahuja, Sanjeev | Bhunia, Haripada
This work aims at modeling and characterizing the kinetics of biodegradation of polypropylene loaded with cobalt stearate as pro-oxidant after abiotic treatment. Eight films of these composites were prepared using different pro-oxidant loadings. These films were treated abiotically using accelerated weathering for 40 h, and biotically using aerobic composting as per ASTM D 5338. The experimental data were analyzed using an eight-parameter Komilis model containing a flat lag phase. The model formulations involved hydrolysis of primary solid carbon and its subsequent mineralization. The first step was rate controlling and it included hydrolysis of slowly (Cₛ), moderately (Cₘ), and readily (Cᵣ) hydrolyzable carbon fractions in parallel. The model parameters were evaluated by means of nonlinear regression technique. The surface morphology of the films before and after the biodegradability test supported the biodegradation results. The model parameters and undegraded/hydrolyzable/mineralizable carbon evolutions involved moderately and readily hydrolyzable carbons but with the absence of slowly hydrolyzable carbon. These exhibit degradability in the range of 11.20-36.42% in 45 days. Biodegradability increases with progressive increase in pro-oxidant loading. The rate of degradation reaches maximum (0.322-0.897% per day) at around the 39th-12th day. For all the films, readily hydrolyzable carbon fractions and their hydrolysis rate constants (kᵣ) are appreciably increased with increasing pro-oxidant loading. All the films show the presence of growth phase because of their high initial readily hydrolyzable carbon fractions. The SEM images after the abiotic and subsequently biotic treatments were progressively rougher. The methods presented here can be used for the design and control of other similar systems.
Mostrar más [+] Menos [-]Quantitation of Heterogeneous Formulations of Morpholine-Type Fungicides and Surfactants in Polluted Soils
2014
Ivanova, Bojidarka | Spiteller, M. (Michael)
The paper reports ultraviolet matrix-assisted laser desorption/ionization mass spectroscopy (UVMALDI-MS) protocol for determination of complex heterogeneous emulsion or suspension formulations. The active agents and surfactants are morpholine fungicide fenpropimorph (1), amorolfine (2), tridemorph (mixture of 2,6-dimethyl-4-alkylmorpholins 3–6), 2,6-dimethyl-4-[2-methyl-3-(6-methyl-decahydro-naphthalen-2-yl)-propyl]-morpholine (7), dodemorph (8), main metabolite of 1 fenpropimorph acid (9), sodium dodecyl sulfate (10), and stearate (11). The full method and techniques validation as well as method performance parameters are discussed in terms of their maximal representativeness toward real environmental and foodstuff assay problems. These are additionally complicated by heterogeneous laterally, vertically, and time distribution of pesticide contaminants and their major metabolites in environmental samples. The real environmental heterogeneous distribution is elucidated, studying sterilized soil fractions with particle size 2.0 μm, clay content 11.5 %, silt 23.0 %, sand 8.1 %, and pH ∈ 6.0–8.1. A statistical sampling cluster approach is used. The method performance parameters are concentration LODs of 0.026 mg kg⁻¹(res. LOQs 0.08666 mg kg⁻¹). Concentration linear dynamic ranges are ∈ 0.025–7.3 mg kg⁻¹(r² = 0.99822 and 0.99421) and ∈ 2.3–7.4 mg kg⁻¹(level of confidence of 99.33₁ %) for complex spiked heterogeneous soil samples. The data illustrates the great capability of method and its promising application for environmental contamination monitoring and controlling programs for assessment.
Mostrar más [+] Menos [-]An innovative material for simultaneous removal of phosphorus and ammonia nitrogen in river water: Preparation and application
2022
Wei, Xinyan | Fu, Xiaori | Zhou, Zhikang | Zhang, Wei | Qian, Xuede | Zeng, Guilu | Lyu, Shuguang
In this study, an innovative material (nitrogen, phosphorus, and oxygen controlling agent, NOC) was synthesized by calcium peroxide (CaO₂), magnesium chloride (MgCl₂), bentonite, zeolite, cement, stearic acid (SA), citric acid (CA), and silver sand. The treatment performance of NOC in mimic black-odor river water was investigated in lab-scale, and the results showed that over 73.7% phosphorus and 77% ammonia nitrogen were removed from river water with the addition of 470 g NOC at 30 mL h⁻¹ flow rate, demonstrating that the presence of NOC could remove phosphorus and ammonia nitrogen simultaneously. Moreover, the addition of NOC could release oxygen with tender influence on pH in water. Calcium phosphate (Ca-P), aluminum phosphate (Al-P), and ferric phosphate (Fe–P) in the river sediment increased from 1.6, 0.136, and 0.12 mg g⁻¹ to 2.16, 0.242, and 0.196 mg g⁻¹ for 28 days, respectively. The results manifested that the mobile phosphorus could be adsorbed by NOC and further transformed to inert phosphorus form, thereby restraining the release of endogenous phosphorus from sediment to the overlying water. Besides, the relative abundance of microorganisms could be enhanced with the existence of NOC, further promoting the removal of phosphorus. Hence, NOC could be applied to the efficient remediation of the black-odor river.
Mostrar más [+] Menos [-]Microparticles and microplastics released from daily use of plastic feeding and water bottles and plastic injectors: potential risks to infants and children in China
2021
Song, Ke | Ding, Runrun | Sun, Caiyun | Yao, Lunguang | Zhang, Weicheng
Daily use of plastic feeding and water bottles occur widely in China, and they could be sources for release of microplastics (MPs), which threaten the health of Chinese infants and children during daily usage. In this work, we investigated the use of polycarbonate (PC) and polypropylene (PP) for making water bottles (WBs) and polyphenylene sulfone resins (PPSU) for making feeding bottles (FBs), and we found that feeding bottles and water bottles released microparticles in amounts ranging from 53 to 393 particles/mL during 100 opening/closing cycles. The good linear regressions for plots of microparticles released vs. abrasion distance (r² = 0.811) indicated that thick-necked bottles release more microparticles than thin-necked bottles. The brands and types of bottles (plastic vs. glass) influence microparticle release, and this indicates that high-quality plastic and glass bottles release fewer microparticles and are good for the health of infants and children. In addition to calcium stearate and silicone additives, the identified MPs account for 7.5 to 42.1% of released microparticles with different polymer types, sizes (from 20 to 500 μm) and shapes (cubic, spherical and irregular shapes). Additionally, an average of 1.74 MPs were released from an injection with a single-use plastic injector. Nevertheless, a number of microparticles and nanosized plastics were observed with all samples, suggesting that the health risks of micro- and nanosized particles to humans, especially babies and children, and the environment should be considered seriously.
Mostrar más [+] Menos [-]Adsorption Kinetics and Capacity of Fatty Acid-Modified Banana Trunk Fibers for Oil in Water
2010
Sathasivam, Kathiresan | Mas Haris, Mas Rosemal Hakim
Oil spill leaves detrimental effects to environment, living organisms, and economy. As such, it is of considerable interest to find an effective, simple, and inexpensive method to treat this calamity. This work reports the use of banana trunk fibers (BTF) modified with oleic acid, stearic acid, castor oil, and palm oil for oil spill recovery. The maximum sorption capacity, effect of oil to water ratio, effect of light oil fractions, and effect of dissolved organic compounds in weathered oil-contaminated seawater were studied. It is found that BTF treated with oleic acid exhibited the best sorption capacity for engine oil, dissolved organic compounds in weathered oil, and light oil fractions. The equilibrium process was described well by the Freundlich isotherm model, and the kinetic studies show good correlation coefficients for a pseudo-second-order kinetic model.
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