scholarly journals Chemical composition of wildfire ash produced in contrasting ecosystems and its toxicity to Daphnia magna

2019 ◽  
Vol 28 (10) ◽  
pp. 726 ◽  
Author(s):  
Ashleigh R. Harper ◽  
Cristina Santin ◽  
Stefan H. Doerr ◽  
Cynthia A. Froyd ◽  
Dania Albini ◽  
...  
Keyword(s):  
Chemical Composition ◽  
Daphnia Magna ◽  
Water Soluble ◽  
Principal Characteristics ◽  
Eucalypt Forest ◽  
Significant Toxicity ◽  
Polycyclic Aromatic ◽  
Elevated Water ◽  
The Uk ◽  
Aquatic Contaminants

It is well established in the world’s fire-prone regions that wildfires can considerably change the hydrological dynamics of freshwater catchments. Limited research, however, has focused on the potential impacts of wildfire ash toxicity on aquatic biota. Here, we assess the chemical composition and toxicity of ash generated from wildfires in six contrasting vegetation types distributed globally (UK grassland, Spanish pine forest, Spanish heathland, USA chaparral, Australian eucalypt forest and Canadian spruce forest). Acute (48h) immobilisation tests were conducted on the extensively studied aquatic macroinvertebrate Daphnia magna, a sensitive indicator of aquatic contaminants. We found significant differences between the chemical composition and toxicity of these ash types. The UK and Spanish ash had no detectable toxicity to Daphnia magna, whereas the Australian eucalypt, USA chaparral and Canadian spruce ash all caused significant toxicity (immobilisation). The principal characteristics of the latter ash types were their high pH, and NO3−, Cl− and conductivity levels. Elevated water-soluble and total concentrations of metals (e.g. Mn, Fe, Zn, Pb, Cu and As) and total polycyclic aromatic hydrocarbons (PAHs) were not linked to toxicity.

scholarly journals Combination of Different Approaches to Infer Local or Regional Contributions to PM2.5 Burdens in Graz, Austria

2020 ◽  
Vol 10 (12) ◽  
pp. 4222
Author(s):  
Bernadette Kirchsteiger ◽  
Magdalena Kistler ◽  
Thomas Steinkogler ◽  
Christopher Herzig ◽  
Andreas Limbeck ◽  
...  
Keyword(s):  
Chemical Composition ◽  
Source Apportionment ◽  
Water Soluble ◽  
The European Union ◽  
Limit Value ◽  
Soluble Ions ◽  
Local Sources ◽  
Polycyclic Aromatic ◽  
Accumulation Of Pollutants ◽  
Short Time

In early 2017 high particulate matter (PM) levels were observed across mid-Europe, including Austria. Here we characterize PM pollution in the city of Graz during January to March 2017, a period with substantial exceedances (34 days) of the European Union (EU) PM10 short time limit value. This study evaluates whether the observed exceedances can be attributed to the accumulation of pollutants emitted by local sources or to a larger scale pollution episode including transport. The analyses are based on the ratios of PM10 concentrations determined at an urban and background site, and the analyses of chemical composition of PM2.5 samples (i.e., water soluble ions, organic and elemental carbon, anhydro-sugars, humic-like substances, aluminum, and polycyclic aromatic hydrocarbons). Source apportionment was realized using a macro-tracer model. Overall, the combination of different approaches (PM10 ratios, chemical composition, and macro-tracer derived source apportionment) enabled a conclusive identification of time periods characterized by the accumulation of emissions from local sources or regional pollution episodes.

scholarly journals Seasonal variations in PM10 inorganic composition in the Andean city

2020 ◽  
Vol 10 (1) ◽  
Author(s):  
Rasa Zalakeviciute ◽  
Katiuska Alexandrino ◽  
Yves Rybarczyk ◽  
Alexis Debut ◽  
Karla Vizuete ◽  
...  
Keyword(s):  
Chemical Composition ◽  
Inductively Coupled Plasma ◽  
Chemical Elements ◽  
Large Fraction ◽  
Urban Pollution ◽  
Optical Emission ◽  
High Elevation ◽  
Water Soluble ◽  
Wet Season ◽  
Soluble Ions

Abstract Particulate matter (PM) is one of the key pollutants causing health risks worldwide. While the preoccupation for increased concentrations of these particles mainly depends on their sources and thus chemical composition, some regions are yet not well investigated. In this work the composition of chemical elements of atmospheric PM10 (particles with aerodynamic diameters ≤ 10 µm), collected at the urban and suburban sites in high elevation tropical city, were chemically analysed during the dry and wet seasons of 2017–2018. A large fraction (~ 68%) of PM10 composition in Quito, Ecuador is accounted for by water-soluble ions and 16 elements analysed using UV/VIS spectrophotometer and Inductively Coupled Plasma—Optical Emission Spectroscopy (ICP-OES). Hierarchical clustering analysis was performed to study a correlation between the chemical composition of urban pollution and meteorological parameters. The suburban area displays an increase in PM10 concentrations and natural elemental markers during the dry (increased wind intensity, resuspension of soil dust) season. Meanwhile, densely urbanized area shows increased total PM10 concentrations and anthropogenic elemental markers during the wet season, which may point to the worsened combustion and traffic conditions. This might indicate the prevalence of cardiovascular and respiratory problems in motorized areas of the cities in the developing world.

Chemical composition and in vitro antioxidant evaluation of a water-soluble Moldavian balm (Dracocephalum moldavica L.) extract

LWT ◽  
2007 ◽  
Vol 40 (2) ◽  
pp. 239-248 ◽  
Author(s):  
Keyvan Dastmalchi ◽  
H.J. Damien Dorman ◽  
Müberra Koşar ◽  
Raimo Hiltunen
Keyword(s):  
Chemical Composition ◽  
Water Soluble ◽  
Antioxidant Evaluation

scholarly journals Mixing state and compositional effects on CCN activity and droplet growth kinetics of size-resolved CCN in an urban environment

2012 ◽  
Vol 12 (21) ◽  
pp. 10239-10255 ◽  
Author(s):  
L. T. Padró ◽  
R. H. Moore ◽  
X. Zhang ◽  
N. Rastogi ◽  
R. J. Weber ◽  
...  
Keyword(s):  
Chemical Composition ◽  
Water Soluble ◽  
Anthropogenic Sources ◽  
Droplet Growth ◽  
Mixing State ◽  
Aerosol Composition ◽  
Activation Kinetics ◽  
Aerosol Mixing State ◽  
Kinetics Of ◽  
Ccn Activity

Abstract. Aerosol composition and mixing state near anthropogenic sources can be highly variable and can challenge predictions of cloud condensation nuclei (CCN). The impacts of chemical composition on CCN activation kinetics is also an important, but largely unknown, aspect of cloud droplet formation. Towards this, we present in-situ size-resolved CCN measurements carried out during the 2008 summertime August Mini Intensive Gas and Aerosol Study (AMIGAS) campaign in Atlanta, GA. Aerosol chemical composition was measured by two particle-into-liquid samplers measuring water-soluble inorganic ions and total water-soluble organic carbon. Size-resolved CCN data were collected using the Scanning Mobility CCN Analysis (SMCA) method and were used to obtain characteristic aerosol hygroscopicity distributions, whose breadth reflects the aerosol compositional variability and mixing state. Knowledge of aerosol mixing state is important for accurate predictions of CCN concentrations and that the influence of an externally-mixed, CCN-active aerosol fraction varies with size from 31% for particle diameters less than 40 nm to 93% for accumulation mode aerosol during the day. Assuming size-dependent aerosol mixing state and size-invariant chemical composition decreases the average CCN concentration overprediction (for all but one mixing state and chemical composition scenario considered) from over 190–240% to less than 20%. CCN activity is parameterized using a single hygroscopicity parameter, κ, which averages to 0.16 ± 0.07 for 80 nm particles and exhibits considerable variability (from 0.03 to 0.48) throughout the study period. Particles in the 60–100 nm range exhibited similar hygroscopicity, with a κ range for 60 nm between 0.06–0.076 (mean of 0.18 ± 0.09). Smaller particles (40 nm) had on average greater κ, with a range of 0.20–0.92 (mean of 0.3 ± 0.12). Analysis of the droplet activation kinetics of the aerosol sampled suggests that most of the CCN activate as rapidly as calibration aerosol, suggesting that aerosol composition exhibits a minor (if any) impact on CCN activation kinetics.

QSARs for photoinduced toxicity: I. Acute lethality of polycyclic aromatic hydrocarbons to Daphnia magna

Chemosphere ◽  
1994 ◽  
Vol 28 (3) ◽  
pp. 567-582 ◽  
Author(s):  
Ovanes G. Mekenyan ◽  
Gerald T. Ankley ◽  
Gilman D. Veith ◽  
Daniel J. Call
Keyword(s):  
Polycyclic Aromatic Hydrocarbons ◽  
Daphnia Magna ◽  
Aromatic Hydrocarbons ◽  
Photoinduced Toxicity ◽  
Polycyclic Aromatic

Transfer of Abrasive Material at Grinding a Titanium Alloy with a Wheel of Cubic Boron Nitride

2021 ◽  
Vol 316 ◽  
pp. 521-526
Author(s):  
Vladimir A. Nosenko ◽  
Alexander V. Fetisov ◽  
Semen P. Kuznetsov
Keyword(s):  
Titanium Alloy ◽  
Chemical Composition ◽  
Boron Nitride ◽  
Chemical Elements ◽  
Cubic Boron Nitride ◽  
Water Soluble ◽  
Alloy Surface ◽  
Ceramic Bond ◽  
Abrasive Tools ◽  
Wear Products

The article summarizes the results of the of the titanium alloy surface morphology and chemical composition study after grinding with a wheel of cubic boron nitride on a ceramic bond. The titanium alloy was treated using the method of cut-in grinding in the finishing mode using a synthetic water-soluble lubricant-cooling liquid that does not contain mineral oil. The research was carried out using the FEI Versa 3D LoVac electron microscope. Digital photos of the titanium alloy surface at different magnifications are given. Individual objects’ morphology allows us to identify them as wear products of abrasive tools. The chemical composition of the selected objects was studied by local x-ray spectral analysis. CBN crystals are partially or completely pressed into the treated surface and covered with a layer of the treated material. On the surface of CBN crystals, there are chemical elements that are part of the abrasive tool bond.

scholarly journals Concentrations and regularities of disperse-phase distribution of organochlorine pesticides, polychlorinated biphenyls and polycyclic aromatic hydrocarbons in natural water

2020 ◽  
Vol 10 (9) ◽  
pp. 867
Author(s):  
Mikhail V. Milyukin ◽  
Maksym V. Gorban ◽  
Maksym V. Gorban
Keyword(s):  
Polycyclic Aromatic Hydrocarbons ◽  
Polychlorinated Biphenyls ◽  
Disperse Phase ◽  
Organochlorine Pesticides ◽  
Aromatic Hydrocarbons ◽  
Phase Distribution ◽  
Water Soluble ◽  
Pollution Levels ◽  
Polycyclic Aromatic ◽  
Average Water

<div><p>This article presents the monitoring results of organochlorine pesticides (OCPs), polychlorinated biphenyls (PCBs), and polycyclic aromatic hydrocarbons (PAHs) in surface water of the Dnieper River for the period 2011–2019. Total levels of OCPs, PCBs and PAHs consist of 1,4–17,1; 2,8–57,2; and 7,5–378,6 ng/L, respectively. A significant increase in pollution levels was not identified. Research results of the disperse-phase distribution of these substances in water were also provided. Less than half of the total contents of pollutants were in the water phase. Average water-soluble parts of OCPs, PCBs, and PAHs accounted for 32, 42, and 44 %, respectively. It was shown that water-soluble parts of individual pollutants decrease with the increase in <span style="text-decoration: line-through;">the</span> coefficients of hydrophobicity of compounds. The clearest reliable, relevant correlation between water-soluble parts of individual congeners and coefficients of hydrophobicity was obtained for PCBs.</p></div><p align="center"><strong><br /></strong></p>

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