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Enhanced removal of per- and polyfluoroalkyl substances in complex matrices by polyDADMAC-coated regenerable granular activated carbon النص الكامل
2022
Ramos, Pia | Singh Kalra, Shashank | Johnson, Nicholas W. | Khor, Chia Miang | Borthakur, Annesh | Cranmer, Brian | Dooley, Gregory | Mohanty, Sanjay K. | Jassby, David | Blotevogel, Jens | Mahendra, Shaily
Granular activated carbon (GAC) has been used to remove per- and polyfluoroalkyl substances (PFASs) from industrial or AFFF-impacted waters, but its effectiveness can be low because adsorption of short-chained PFASs is ineffective and its sites are exhausted rapidly by co-contaminants. To increase adsorption of anionic PFASs on GAC by electrostatic attractions, we modified GAC's surface with the cationic polymer poly diallyldimethylammonium chloride (polyDADMAC) and tested its capacity in complex water matrices containing dissolved salts and humic acid. Amending with concentrations of polyDADMAC as low as 0.00025% enhanced GAC's adsorption capacity for PFASs, even in the presence of competing ions. This suggests that electrostatic interactions with polyDADMAC's quaternary ammonium functional groups helped bind organic and inorganic ions as well as the headgroup of short-chain PFASs, allowing more overall PFAS removal by GAC. Evaluating the effect of polymer dose is important because excessive addition can block pores and reduce overall PFAS removal rather than increase it. To decrease the waste associated with this adsorption strategy by making the adsorbent viable for more than one saturation cycle, a regeneration method is proposed which uses low-power ultrasound to enhance the desorption of PFASs from the polyDADMAC-GAC with minimum disruption to the adsorbent's structure. Re-modification with the polymer after sonication resulted in a negligible decrease in the sorbent's capacity over four saturation rounds. These results support consideration of polyDADMAC-modified GAC as an effective regenerable adsorbent for ex-situ concentration step of both short and long-chain PFASs from real waters with high concentrations of competing ions and low PFAS loads.
اظهر المزيد [+] اقل [-]Traffic noise playback reduces the activity and feeding behaviour of free-living bats النص الكامل
2020
Finch, Domhnall | Schofield, Henry | Mathews, Fiona
Increasing levels of road noise are creating new anthropogenic soundscapes that may affect wildlife globally. Bats, which form about a third of all mammal species, are sensitive bioindicators, and may be particularly vulnerable because of their dependency on echolocation. Here we present the first controlled field experiment with free-living bats. Using a Before-After-Control-Impact phantom road experimental design, we examine the impacts of traffic noise on their activity and feeding behaviour. Disentangling the impacts of traffic noise from other co-varying exposures such as habitat quality, the experiment demonstrates a significant negative effect on the activity of each of the five, ecologically different, species (genus for Myotis spp.) examined. This suggests that the results are widely applicable. The negative effects are largely attributable to noise in the sonic spectrum, which elicited aversive responses in all bat species tested,whereas responses to ultrasoundwere restricted to a single species. Our findings demonstrate that traffic noise can affect bat activity at least 20m away from the noise source. For Pipistrellus pipistrellus and Pipistrellus pygmaeus, feeding behaviour, as well as overall activity, was negatively affected. Ecological Impact Assessments are therfore needed wherever there are significant increases in traffic flow, and not just when new roads are built. Further research is required to identify effective mitigation strategies, to delineate the zone of influence of road noise, and to assess whether there is any habituation over time.
اظهر المزيد [+] اقل [-]Molecular identification of polymers and anthropogenic particles extracted from oceanic water and fish stomach – A Raman micro-spectroscopy study النص الكامل
2018
Ghosal, Sutapa | Chen, Michael | Wagner, Jeff | Wang, Zhong-Min | Wall, Stephen
Pacific Ocean trawl samples, stomach contents of laboratory-raised fish as well as fish from the subtropical gyres were analyzed by Raman micro-spectroscopy (RMS) to identify polymer residues and any detectable persistent organic pollutants (POP). The goal was to access specific molecular information at the individual particle level in order to identify polymer debris in the natural environment. The identification process was aided by a laboratory generated automated fluorescence removal algorithm. Pacific Ocean trawl samples of plastic debris associated with fish collection sites were analyzed to determine the types of polymers commonly present. Subsequently, stomach contents of fish from these locations were analyzed for ingested polymer debris. Extraction of polymer debris from fish stomach using KOH versus ultrapure water were evaluated to determine the optimal method of extraction. Pulsed ultrasonic extraction in ultrapure water was determined to be the method of choice for extraction with minimal chemical intrusion. The Pacific Ocean trawl samples yielded primarily polyethylene (PE) and polypropylene (PP) particles >1 mm, PE being the most prevalent type. Additional microplastic residues (1 mm - 10 μm) extracted by filtration, included a polystyrene (PS) particle in addition to PE and PP. Flame retardant, deca-BDE was tentatively identified on some of the PP trawl particles. Polymer residues were also extracted from the stomachs of Atlantic and Pacific Ocean fish. Two types of polymer related debris were identified in the Atlantic Ocean fish: (1) polymer fragments and (2) fragments with combined polymer and fatty acid signatures. In terms of polymer fragments, only PE and PP were detected in the fish stomachs from both locations. A variety of particles were extracted from oceanic fish as potential plastic pieces based on optical examination. However, subsequent RMS examination identified them as various non-plastic fragments, highlighting the importance of chemical analysis in distinguishing between polymer and non-polymer residues.
اظهر المزيد [+] اقل [-]Enhanced organic contaminants accumulation in crops: Mechanisms, interactions with engineered nanomaterials in soil النص الكامل
2018
Wu, Xiang | Wang, Wei | Zhu, Lizhong
The mechanism of enhanced accumulation of organic contaminants in crops with engineered nanomaterials (ENMs) were investigated by co-exposure of crops (Ipomoea aquatica Forsk (Swamp morning-glory), Cucumis sativus L. (cucumber), Zea mays L. (corn), Spinacia oleracea L. (spinach) and Cucurbita moschata (pumpkin))to a range of chemicals (polycyclic aromatic hydrocarbons (PAHs), organochlorine pesticides (OCPs) and polybrominated diphenyl ether (PBDE)) and ENMs (TiO2, Ag, Al2O3, graphene, carbon nanotubes (CNTs)) in soil. Induced by 50 mg kg−1 graphene co-exposure, the increase range of BDE-209, BaP, p,p′-DDE, HCB, PYR, FLU, ANT, and PHEN in the plants were increased in the range of 7.51–36.42, 5.69–32.77, 7.09–59.43, 11.61–66.73, 4.58–57.71, 5.79–109.07, 12.85–109.76, and15.57–127.75 ng g−1, respectively. The contaminants in ENMs-spiked and control soils were separated into bioavailable, bound and residual fractions using a sequential ultrasonic extraction procedure (SUEP) to investigate the mechanism of the enhanced accumulation. The bioavailable fraction in spiked soils showed no significant difference (p > 0.05) from that in the control, while the bound fraction increased in equal proportion (p > 0.05) to the reduction in the residual fraction. These results implied that ENMs can competitively adsorbed the bound of organic contaminants from soil and co-transferred into crops, followed by a portion of the residual fraction transferred to the bound fraction to maintain the balance of different fractions in soils. The mass balance was all higher than 98.5%, indicating the portion of degraded contaminants was less than 1.5%. These findings could expand our knowledge about the organic contaminants accumulation enhancement in crops with ENMs.
اظهر المزيد [+] اقل [-]Assessment of organochlorine pesticide residues in Atlantic Rain Forest fragments, Rio de Janeiro, Brazil النص الكامل
2011
Quinete, Natalia Soares | de Oliveira, Elba dos Santos | Fernandes, Daniella R. | Avelar, Andre de Souza | Santelli, Ricardo Erthal
A superficial water quality survey in a watershed of the Paraíba do Sul River, the main water supply for the most populated cities of southeastern Brazil, was held in order to assess the impact of the expansion of agricultural activity in the near border of the Atlantic Rain Forest. The aim of this study was to investigate the presence of priority organochlorine pollutants in soils and superficial waters of Atlantic rainforest fragments in Teresópolis, Rio de Janeiro State. Soil sample preparations were compared by using ultrasound, microwave assisted extraction and Soxhlet extraction. Recoveries of matrix spiked samples ranged from 70 to 130%. Analysis of a certified soil material showed recoveries ranging from 71 to 234%. Although low concentrations of organochlorine residues were found in water and soil samples, this area is of environmental importance and concern, thus demanding a monitoring program of its compartments.
اظهر المزيد [+] اقل [-]Enzymatic probe sonication for quick extraction of total bisphenols from animal-derived foods: Applicability to occurrence and exposure assessment النص الكامل
2022
Xiao, Zhiming | Wang, Shi | Suo, Decheng | Wang, Ruiguo | Huang, Yuan | Su, Xiaoou
A high demand exists in bisphenols (BPs) screening studies for quick, reliable and straightforward analytical methods that generate data faster and simultaneously. Herein, we describe a combination of enzymatic probe sonication (EPS) and ultra-performance liquid chromatography-tandem mass spectrometry (UPLC-MS/MS) for quick extraction and simultaneous quantification of eight important BPs in animal-derived foods. Results obtained demonstrated that the ultrasonic probe power could not only enhance the enzymatic hydrolysis efficiency, but also accelerate the liquid-liquid extraction procedure. Under optimized EPS parameters, one sample could be exhaustively extracted within 120 s, as compared with 12 h needed for the conventional enzymatic extraction which is more suitable for high-throughput analysis. The method was successfully applied to analyze residual BPs in animal-derived foods collected from Beijing, China. Widespread occurrence of BPA, BPS, BPF, BPAF, BPP, and BPB were found, with detection frequencies of 65.2%, 42.4%, 33.7%, 29.4%, 28.3%, and 27.2%, respectively. The highest total concentration levels of BPs (sum of the eight BPs analyzed, ΣBPs) were found in chicken liver (mean 12.2 μg/kg), followed by swine liver (6.37 μg/kg), bovine muscle (3.24 μg/kg), egg (2.03 μg/kg), sheep muscle (2.03 μg/kg), chicken muscle (1.45 μg/kg), swine muscle (1.42 μg/kg), and milk (1.17 μg/kg). The estimated daily intake (EDI) of BPs, based on the mean and 95th percentile concentrations and daily food consumptions, was estimated to be 5.687 ng/kg bw/d and 22.71 ng/kg bw/d, respectively. The human health risk assessment in this work suggests that currently BPs do not pose significant risks to the consumers because the hazard index (HI) was <1.
اظهر المزيد [+] اقل [-]Relationship between life-time exposure to ambient fine particulate matter and carotid artery intima-media thickness in Australian children aged 11–12 years النص الكامل
2021
Guo, Yue Leon | Ampon, Rosario D. | Hanigan, Ivan C. | Knibbs, Luke D. | Geromboux, Christy | Su, Ta-Chen | Negishi, Kazuaki | Poulos, Leanne | Morgan, Geoffrey G. | Marks, Guy B. | Jalaludin, Bin
Long-term exposure to air pollutants, especially particulates, in adulthood is related to cardiovascular diseases and vascular markers of atherosclerosis. However, whether vascular changes in children is related to exposure to air pollutants remains unknown. This study examined whether childhood exposure to air pollutants was related to a marker of cardiovascular risk, carotid intima–media thickness (CIMT) in children aged 11–12 years old. Longitudinal Study of Australian Children (LSAC) recruited parents and their children born in 2003–4. Among the participants, CheckPoint examination was conducted when the children were 11–12 years old. Ultrasound of the right carotid artery was performed using standardized protocols. Average and maximum far-wall CIMT, carotid artery distensibility, and elasticity were quantified using semiautomated software. Annual and life-time exposure to air pollutants was estimated using satellite-based land-use regression by residential postcodes. A total of 1063 children (50.4% girls) with CIMT data, serum cholesterol, and modeled estimates of NO₂ and PM₂.₅ exposure for the period 2003 to 2015 were included. The average and maximum CIMT, carotid distensibility, and elasticity were 497 μm (standard deviation, SD 58), 580 μm (SD 44), 17.4% (SD 3.2), and 0.48%/mmHg (SD 0.09), respectively. The life-time average concentrations of PM₂.₅ and NO₂ were 6.4 μg/m³ (SD 1.4) and 6.4 ppb (SD 2.4), respectively. Both average and maximum CIMT were significantly associated with average ambient PM₂.₅ concentration (average CIMT: +5.5 μm per μg/m³, 95% confidence interval, CI 2.4 to 8.5, and maximum CIMT: +4.9 μm per μg/m³, CI 2.3 to 7.6), estimated using linear regression, adjusting for potential confounders. CIMT was not significantly related to NO₂ exposure. Carotid artery diameter, distensibility, and elasticity were not significantly associated with air pollutants. We conclude that life-time exposure to low levels of PM₂.₅ in children might have measurable adverse impacts on vascular structure by age 11–12 years.
اظهر المزيد [+] اقل [-]Potential transfer of organic pollutants from littoral plastics debris to the marine environment النص الكامل
2018
León, Víctor M. | García, Inés | González, Emilia | Samper, Raquel | Fernández-González, Verónica | Muniategui-Lorenzo, Soledad
Potential transfer of organic pollutants from littoral plastics debris to the marine environment النص الكامل
2018
León, Víctor M. | García, Inés | González, Emilia | Samper, Raquel | Fernández-González, Verónica | Muniategui-Lorenzo, Soledad
Plastic polymers act as passive samplers in air system and concentrate hydrophobic organic contaminants by sorption or specific interactions, which can be transported to other systems such as the marine environment. In this study plastic debris was sampled in the surrounding area of a Mediterranean lagoon in order to determine the concentration of persistent and emerging organic contaminants. More specifically, desorption of 91 regulated and emerging organic contaminants (polycyclic aromatic hydrocarbons, polychlorinated biphenyls, organochlorinated pesticides, current-use pesticides, personal care products, other pesticides and plastic additives) was characterized for the first 24 h from different polymers to seawater and the remaining content of these contaminants was also extracted by ultrasonic extraction with methanol. All samples were analyzed by Stir Bar Sorptive Extraction coupled to GC/MS. A significant fraction of sorbed contaminants in polymers was desorbed in the first 24 h, particularly for triazines and organophosphorus pesticides due to their lower hydrophobicity than other considered analytes. The remaining contaminants contained in plastics can be also transferred to seawater, sediments or biota. Considering 24 h desorbed fraction plus the remaining methanol extracted fraction, the highest transfer levels corresponded to personal care products, plastic additives, current-use pesticides and PAHs. This is the first study to show the relevance of the transport of organic contaminants on plastic debris from littoral areas to the marine environment.
اظهر المزيد [+] اقل [-]Potential transfer of organic pollutants from littoral plastics debris to the marine environment النص الكامل
2018
León, Víctor Manuel | García-de-la-Banda, Inés | González-García, Emilio | Samper, R. | Fernández-González, V. | Muniategui-Lorenzo, S.
Plastic polymers act as passive samplers in air system and concentrate hydrophobic organic contaminants by sorption or specific interactions, which can be transported to other systems such as the marine environment. In this study plastic debris was sampled in the surrounding area of a Mediterranean lagoon in order to determine the concentration of persistent and emerging organic contaminants. More specifically, desorption of 91 regulated and emerging organic contaminants (polycyclic aromatic hydrocarbons, polychlorinated biphenyls, organochlorinated pesticides, current-use pesticides, personal care products, other pesticides and plastic additives) was characterized for the first 24 h from different polymers to seawater and the remaining content of these contaminants was also extracted by ultrasonic extraction with methanol. All samples were analyzed by Stir Bar Sorptive Extraction coupled to GC/MS. A significant fraction of sorbed contaminants in polymers was desorbed in the first 24 h, particularly for triazines and organophosphorus pesticides due to their lower hydrophobicity than other considered analytes. The remaining contaminants contained in plastics can be also transferred to seawater, sediments or biota. Considering 24 h desorbed fraction plus the remaining methanol extracted fraction, the highest transfer levels corresponded to personal care products, plastic additives, current-use pesticides and PAHs. This is the first study to show the relevance of the transport of organic contaminants on plastic debris from littoral areas to the marine environment. | Sí
اظهر المزيد [+] اقل [-]Fabrication of activated carbon supported modified with bimetallic-platin ruthenium nano sorbent for removal of azo dye from aqueous media using enhanced ultrasonic wave النص الكامل
2022
Herein, activated carbon supported modified with bimetallic-platin ruthenium nano sorbent (PtRu@AC) was synthesized by a thermal decomposition process and used in the removal of methylene blue (MB) from aqueous solutions. The synthesized nano sorbents were characterized by X-ray Diffraction (XRD), Transmission Electron Microscopy (TEM), and X-ray Photoelectron Spectroscopy (XPS) spectroscopic techniques. The data obtained from characterization studies showed that PtRu@AC nano sorbent was highly crystalline and in a form of PtRu alloy with a monodispersed composition. The results indicated that the maximum adsorption capacity (qemax) for the removal of MB with PtRu@AC under optimum conditions was detected to be 1.788 mmol/g (569.4 mg/g). The experimental kinetic results of the study revealed that the adsorption of methylene blue was found to be more compatible with the false second-order model compared to some tested models. Calculations for thermodynamic functions including enthalpy change (ΔHo), entropy change (ΔSo), and Gibbs free energy change (ΔGo) values were performed to get an idea about the adsorption mechanism. As a result, the synthesized PtRu@AC nano adsorbent was detected as a highly effective adsorbent material in the removal of MB from aquatic mediums.
اظهر المزيد [+] اقل [-]Facile nanoplastics formation from macro and microplastics in aqueous media النص الكامل
2022
Peller, Julie R. | Mezyk, Stephen P. | Shidler, Sarah | Castleman, Joe | Kaiser, Scott | Faulkner, Richard F. | Pilgrim, Corey D. | Wilson, Antigone | Martens, Sydney | Horne, Gregory P.
The immense production of plastic polymers combined with their discordancy with nature has led to vast plastic waste contamination across the geosphere, from the oceans to freshwater reservoirs, wetlands, remote snowpacks, sediments, air and multiple other environments. These environmental pollutants include microplastics (MP), typically defined as small and fragmented plastics less than 5 mm in size, and nanoplastics (NP), particles smaller than a micrometer. The formation of micro and nanoplastics in aqueous media to date has been largely attributed to fragmentation of plastics by natural (i.e., abrasion, photolysis, biotic) or industrial processes. We present a novel method to create small microplastics (≲ 5 μm) and nanoplastics in water from a wide variety of plastic materials using a small volume of a solubilizer liquid, such as n-dodecane, in combination with vigorous mixing. When the suspensions or solutions are subjected to ultrasonic mixing, the particle sizes decrease. Small micro- and nanoparticles were made from commercial, real world and waste (aged) polyethylene, polystyrene, polycarbonate and polyethylene terephthalate, in addition to other plastic materials and were analyzed using dark field microscopy, Raman spectroscopy and particle size measurements. The presented method provides a new and simple way to create specific size distributions of micro- and nanoparticles, which will enable expanded research on these plastic particles in water, especially those made from real world and aged plastics. The ease of NP and small MP formation upon initial mixing simulates real world environments, thereby providing further insight into the behavior of plastics in natural settings.
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