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Sublethal effect of agronomical surfactants on the spider Pardosa agrestis
2016
Niedobová, Jana | Hula, Vladimír | Michalko, Radek
In addition to their active ingredients, pesticides contain also additives – surfactants. Use of surfactants has been increasing over the past decade, but their effects on non-target organisms, especially natural enemies of pests, have been studied only very rarely. The effect of three common agrochemical surfactants on the foraging behavior of the wolf spider Pardosa agrestis was studied in the laboratory. Differences in short-term, long-term, and overall cumulative predatory activities were investigated. We found that surfactant treatment significantly affected short-term predatory activity but had no effect on long-term predatory activity. The surfactants also significantly influenced the cumulative number of killed prey. We also found the sex-specific increase in cumulative kills after surfactants treatment. This is the first study showing that pesticide additives have a sublethal effect that can weaken the predatory activity of a potential biological control agent. More studies on the effects of surfactants are needed to understand how they affect beneficial organisms in agroecosystems.
Afficher plus [+] Moins [-]Fin whales and microplastics: The Mediterranean Sea and the Sea of Cortez scenarios
2016
Fossi, Maria Cristina | Marsili, Letizia | Baini, Matteo | Giannetti, Matteo | Coppola, Daniele | Guerranti, Cristiana | Caliani, Ilaria | Minutoli, Roberta | Lauriano, Giancarlo | Finoia, Maria Grazia | Rubegni, Fabrizio | Panigada, Simone | Bérubé, Martine | Urbán Ramírez, Jorge | Panti, Cristina
The impact that microplastics have on baleen whales is a question that remains largely unexplored. This study examined the interaction between free-ranging fin whales (Balaenoptera physalus) and microplastics by comparing populations living in two semi-enclosed basins, the Mediterranean Sea and the Sea of Cortez (Gulf of California, Mexico). The results indicate that a considerable abundance of microplastics and plastic additives exists in the neustonic samples from Pelagos Sanctuary of the Mediterranean Sea, and that pelagic areas containing high densities of microplastics overlap with whale feeding grounds, suggesting that whales are exposed to microplastics during foraging; this was confirmed by the observation of a temporal increase in toxicological stress in whales. Given the abundance of microplastics in the Mediterranean environment, along with the high concentrations of Persistent Bioaccumulative and Toxic (PBT) chemicals, plastic additives and biomarker responses detected in the biopsies of Mediterranean whales as compared to those in whales inhabiting the Sea of Cortez, we believe that exposure to microplastics because of direct ingestion and consumption of contaminated prey poses a major threat to the health of fin whales in the Mediterranean Sea.
Afficher plus [+] Moins [-]Development of an analytical method for determining hindered phenolic antioxidants in exhaust emissions from light-duty vehicles
2016
Wang, Jingxian | Thomson, Meghan | Connolly, Trevor | Tong, Anthony Z.
Six hindered phenolic antioxidants (HPAs) from emissions of light-duty diesel and gasoline vehicles were determined. Vehicles were tested on a dynamometer that conducted a typical city-driving protocol and their exhaust samples were collected on filters. A high-performance liquid chromatography coupled with tandem mass spectrometry (HPLC-MS/MS) method was developed for the determination of HPAs in the exhaust samples. Method detection limits reached low ng/m3 in exhaust after optimization of experimental conditions. Identification and quantification were proven to be reliable for these phenols in lightly-loaded and ambient filter samples. In heavily loaded samples, matrix interferences existed, which decreased recoveries of surrogate in both filter and disk. However, matrix spike samples showed good recoveries of target HPAs. In vehicle emission samples, the highest level of HPAs was 2,6-di-tert-butylphenol at 52.7 ng/m3 (28.9 pg/mm2 on filter) in emission of a 2009 Volkswagen Jetta with a diesel engine. Most HPAs were not detected or near detection limits. Therefore, the additives of phenol antioxidants in fuels were mostly oxidized during the combustion process. Further, the 2009 diesel Jetta produced about 7 times more of HPAs than the 2008 Pontiac G5 with a gasoline engine. In addition, it is discovered that engines operated at a colder ambient temperature (−7 °C) yielded more HPA emissions than at the warmer condition (25 °C), because the combustion efficiency of engines are normally reduced at a lower temperature.
Afficher plus [+] Moins [-]Esterase activity (EA), total oxidant status (TOS) and total antioxidant capacity (TAC) in gills of Mytilus galloprovincialis exposed to pollutants: Analytical validation and effects evaluation by single and mixed heavy metal exposure
2016
Franco Vidal, Lorena | Romero, Diego | García-Navarro, José A. | Teles, Mariana | Tvarijonaviciute, Asta
The aims of the present study were to optimize and validate methods for esterase activity (EA), total oxidant status (TOS) and total antioxidant capacity (TAC) determination in mussel' gills, and to establish the relationships between these biomarkers and Pb, Cd and Cu pollution, in single form and ternary mixture. Two different buffers for sample homogenization, the need of ultracentrifugation, and analytical validation were evaluated. Coefficients of variation, when buffer without additives and ultracentrifugation were used, were <15%, and recovery were 97%–109% in all cases. The EA response tends to decrease with treatments, TOS decreased significantly in Cd and ternary groups, while TAC tended to increase in treatments with Pb, Cd and ternary groups. In conclusion, the methods for EA, TOS and TAC measurements in gills of mussel were precise and accurate and could be interesting resources in biomonitoring programmes.
Afficher plus [+] Moins [-]Qualitative impact of salinity, UV radiation and turbulence on leaching of organic plastic additives from four common plastics — A lab experiment
2016
Suhrhoff, Tim Jesper | Scholz-Böttcher, Barbara M.
Four common consumer plastic samples (polyethylene, polystyrene, polyethylene terephthalate, polyvinylchloride) were studied to investigate the impact of physical parameters such as turbulence, salinity and UV irradiance on leaching behavior of selected plastic components. Polymers were exposed to two different salinities (i.e. 0 and 35g/kg), UV radiation and turbulence. Additives (e.g. bisphenol A, phthalates, citrates, and Irgafos® 168 phosphate) and oligomers were detected in initial plastics and aqueous extracts. Identification and quantification was performed by GC–FID/MS. Bisphenol A and citrate based additives are leached easier compared to phthalates. The print highly contributed to the chemical burden of the analyzed polyethylene bag. The study underlines a positive relationship between turbulence and magnitude of leaching. Salinity had a minor impact that differs for each analyte. Global annual release of additives from assessed plastics into marine environments is estimated to be between 35 and 917tons, of which most are derived from plasticized polyvinylchloride.
Afficher plus [+] Moins [-]Aluminum-Enhanced Coal Pyrite Leaching during SO2 Removal with Coal Slurry
2016
Sun, Wenshou | Liu, Jingchun | Wang, Lichao | Yi, Yanqing
During SO₂ removal from flue gas by coal slurry scrubbing, coal pyrite sulfur can be simultaneously reduced. But satisfactory coal pyrite conversion cannot be achieved under normal scrubbing conditions. In the present work, aluminum oxide and aluminum sulfate were tested as additives to enhance the leaching of coal pyrite during SO₂ removal in a bubbling reactor. It was found that adding aluminum oxide or aluminum sulfate into the coal slurry could increase the coal pyrite conversion and SO₂ removal efficiency. The leaching process could be described by the reaction-controlled shrinking core model. Based on the facts that both aluminum and ferric irons can exist in aqueous solution in the form of sulfate and hydroxide complex ions, it was deduced that the attraction between the oppositely charged ions might promote the coal pyrite leaching reactions, suppress the formation of passive Fe solid products, and increase the concentration of soluble complexed Fe(III) which also acted as coal pyrite oxidant.
Afficher plus [+] Moins [-]Improving the environmental and performance characteristics of vehicles by introducing the surfactant additive into gasoline
2016
Magaril, Elena | Magaril, Romen
The operation of modern vehicles requires the introduction of package of fuel additives to ensure the required level of operating characteristics, some of which cannot be achieved by current oil refining methods. The use of additives allows flexibility of impact on the properties of the fuel at minimal cost, increasing the efficiency and environmental safety of vehicles. Among the wide assortment of additives available on the world market, many are surfactants. It has been shown that the introduction of some surfactants into gasoline concurrently reduces losses from gasoline evaporation, improves the mixture formation during injection of gasoline into the engine and improves detergent and anticorrosive properties. The surfactant gasoline additive that provides significant improvement in the quality of gasoline used and environmental and operating characteristics of vehicles has been developed and thoroughly investigated. The results of studies confirming the efficiency of the gasoline additive application are herein presented.
Afficher plus [+] Moins [-]Experimental Investigation and Numerical Modeling of Enhanced DNAPL Solubilization in Saturated Porous Media
2016
Aydin-Sarikurt, Derya | Dokou, Zoi | Copty, NadimK. | Karatzas, GeorgeP.
The accidental release of organic contaminants in the form of non-aqueous phase liquids (NAPLs) into the subsurface is a widespread and challenging environmental problem. Successful remediation of sites contaminated with NAPLs is essential for the protection of human health and the environment. One technology that has received significant attention is the injection of chemical additives (such as cosolvents) upgradient of the NAPL zone for the enhanced dissolution and mobilization of the NAPL mass. A key process influencing the effectiveness of NAPL mass recovery is the interphase mass transfer which is the transfer of components across the interface separating the different phases. In this work, we examine the impact of cosolvent content, flushing solution velocity, and injection pattern (continuous versus intermittent) on the interphase mass transfer rate. A series of flushing experiments were conducted using an intermediate-scale tank which allows for the impact of density variations on DNAPL mobility. The target DNAPL selected in this study was trichloroethylene while the flushing solutions consisted of ethanol–water mixtures with ethanol contents ranging from 0 to 50% by volume. The experimental results were also modeled using the UTCHEM multiphase flow simulator that was modified to model cosolvent flushing. Results show that the observed interphase mass transfer coefficient, expressed as a modified Sherwood number, was much lower than predicted based on published correlations developed under idealized conditions. Moreover, interphase mass transfer rate decreased with time, indicating that a single interphase mass transfer coefficient cannot accurately model the entire flushing solution. The data also suggest that the interphase mass transfer coefficient is dependent on cosolvent content.
Afficher plus [+] Moins [-]Achromobacter xylosoxidans as a new microorganism strain colonizing high-density polyethylene as a key step to its biodegradation
2016
Kowalczyk, Anna | Chyc, Marek | Ryszka, Przemysław | Latowski, Dariusz
This study presents results of research on isolation new bacteria strain Achromobacter xylosoxidans able to effect on the structure of high-density polyethylene (HDPE), polymer resistant to degradation in environment. New strain of A. xylosoxidans PE-1 was isolated from the soil and identified by analysis of the 16S ribosome subunit coding sequences. The substance to be degraded was HDPE in the form of thin foil films. The foil samples were analyzed with Attenuated Total Reflectance Fourier Transform Infrared Spectroscopy (ATR-FTIR) as well as scanning electron microscope (SEM), and the results revealed degradation of chemical structure of HDPE. About 9 % loss of weight was also detected as a result of A. xylosoxidans PE-1 effect on HDPE foil. On the basis of comparative spectral analysis of the raw material before the bacteria treatment and the spectrum from a spectra database, it was assumed that the HDPE was the only source of carbon and energy for the microorganisms. No fillers or other additives used in the plastic processing were observed in HDPE before experiments. This is the first communication showing that A. xylosoxidans is able to modify chemical structure of HDPE, what was observed both on FTIR, in mass reduction of HDPE and SEM analysis. We also observed quite good growth of the bacteria also when the HDPE was the sole carbon source in the medium. These results prove that A. xylosoxidans is an organism worth applying in future HDPE biodegradation studies.
Afficher plus [+] Moins [-]Effects of the addition of iron and aluminum salt on phosphorus adsorption in wetland sediment
2016
Huang, Shuhui | Huang, Hong | Zhu, Huayue
Adsorption and removal of phosphorus (P) in wetland sediment from aqueous solutions were investigated by using four kinds of iron (Fe) and aluminum (Al) salt (FeCl₃, AlCl₃, poly FeCl₃, and poly AlCl₃). Under optimal temperature of 25 °C, P concentration of 50 mg/L, and mole concentration ratio of 4:1 (Fe³⁺/PO₄ ³⁻ or Al³⁺/PO₄ ³⁻), the P sorption capacities of wetland sediments by FeCl₃, poly FeCl₃, AlCl₃, and poly AlCl₃treatments were 296.03, 371.41, 276.3, and 357.85 μg/g, respectively, and were enhanced by 83.36, 158.74, 63.63, and 145.18 μg/g, respectively. The P sorption capacities based on different additives were in the order of poly FeCl₃ > poly AlCl₃ > FeCl₃ > AlCl₃. The EPC0 values, K values, and maximum adsorption capacities indicated that poly FeCl₃ was good reagent to restore P pollution in aqueous solution by wetland sediment in the consideration of both P treatment efficiency and potential environmental impact. These findings, obviously, are useful basis to develop new effective methods for P removal in waters.
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