scholarly journals Experimental evidence for recovery of mercury-contaminated fish populations

Nature ◽  
2021 ◽  
Author(s):  
Paul J. Blanchfield ◽  
John W. M. Rudd ◽  
Lee E. Hrenchuk ◽  
Marc Amyot ◽  
Christopher L. Babiarz ◽  
...  
Keyword(s):  
Experimental Evidence ◽  
Aquatic Ecosystems ◽  
Wet Deposition ◽  
Fish Populations ◽  
Single Factor ◽  
Deposition Rates ◽  
Microbial Methylation ◽  
High Concentrations ◽  
Single Factor Experiment ◽  
Hg Pollution

AbstractAnthropogenic releases of mercury (Hg)1–3 are a human health issue4 because the potent toxicant methylmercury (MeHg), formed primarily by microbial methylation of inorganic Hg in aquatic ecosystems, bioaccumulates to high concentrations in fish consumed by humans5,6. Predicting the efficacy of Hg pollution controls on fish MeHg concentrations is complex because many factors influence the production and bioaccumulation of MeHg7–9. Here we conducted a 15-year whole-ecosystem, single-factor experiment to determine the magnitude and timing of reductions in fish MeHg concentrations following reductions in Hg additions to a boreal lake and its watershed. During the seven-year addition phase, we applied enriched Hg isotopes to increase local Hg wet deposition rates fivefold. The Hg isotopes became increasingly incorporated into the food web as MeHg, predominantly from additions to the lake because most of those in the watershed remained there. Thereafter, isotopic additions were stopped, resulting in an approximately 100% reduction in Hg loading to the lake. The concentration of labelled MeHg quickly decreased by up to 91% in lower trophic level organisms, initiating rapid decreases of 38–76% of MeHg concentration in large-bodied fish populations in eight years. Although Hg loading from watersheds may not decline in step with lowering deposition rates, this experiment clearly demonstrates that any reduction in Hg loadings to lakes, whether from direct deposition or runoff, will have immediate benefits to fish consumers.

Testing Study on the Influence Factors to the Straw Pellet Fuel Broken Strength

2013 ◽  
Vol 448-453 ◽  
pp. 786-790
Author(s):  
Wei Gao ◽  
Rong Fei Zhao ◽  
Qing Yu Liu ◽  
Xu Wei Bai
Keyword(s):  
Moisture Content ◽  
Optimal Parameter ◽  
Influence Factors ◽  
Raw Material ◽  
Single Factor ◽  
Quadratic Regression ◽  
Corn Straw ◽  
Fermentation Time ◽  
Optimization Parameter ◽  
Single Factor Experiment

This paper take link mold pellet pelletizer to carry on the pellet fuel manufacture experiment with corn straw stalk. The influence of moisture content, material size and fermentation time impact on broken strength is studied by single factor experiment. Through quadratic regression orthogonal rotating combination experiment, establish mathematics equation of the factors and the straw pellet fuel broken strength and analyze the important degree of each experimental factor impact on the granulation rate. Through the optimized computation, definite optimization parameter of the highest broken strength is that raw material moisture content is 20%, fermentation time is 4h and particle size is 2.5mm. The result of verifying experiment indicat that the optimal parameter combination and the predict data measured were consistent.

ADMINISTRATION OF GLUCURONIC ACID TO ICTERIC NEWBORN INFANTS

PEDIATRICS ◽  
1959 ◽  
Vol 23 (1) ◽  
pp. 92-97
Author(s):  
Gloria Jeliu ◽  
Rudi Schmid ◽  
Sydney Gellis
Keyword(s):  
Experimental Evidence ◽  
Exchange Transfusion ◽  
Glucuronic Acid ◽  
Newborn Infants ◽  
Significant Change ◽  
High Concentrations

Fourteen icteric newborn infants were treated with varying amounts of glucuronic acid or sodium glucuronate, administered by oral or intravenous routes. No significant change in concentration of bilirubin in the serum was observed. Experimental evidence and biochemical considerations do not suggest that the administration of glucuronic acid enhances the formation of bilirubin glucuronide. It is the authors' opinion that at present the use of glucuronic acid should not be considered as an alternative for exchange transfusion in the treatment of newborn infants with high concentrations of bilirubin in the serum.

Study on the Antibacterial Performance of the Antibacterial Shutter Blades

2013 ◽  
Vol 815 ◽  
pp. 333-338
Author(s):  
Ming Li Liu ◽  
Chun Feng Li ◽  
Yun Long Wang ◽  
Kai Lu ◽  
Jiu Yin Pang ◽  
...  
Keyword(s):  
Antibacterial Agent ◽  
Antibacterial Agents ◽  
Drug Loading ◽  
Antibacterial Properties ◽  
Water Soluble ◽  
Single Factor ◽  
Antibacterial Performance ◽  
Loading Amount ◽  
Single Factor Experiment ◽  
Impregnation Solution

This study used Ag-embedded nanoTiO2, xylan and water-soluble Chitosan as antibacterial agents, respectively prepared shutter blades through the treating solution of the different concentration and the different drug loading amount of the poplar veneer. Through a single factor experiment, this paper analyzes that the different antibacterial agent, concentration of antibacterial agent and the drug loading amount have an effect on the antibacterial properties of the shutter blades. The results show that the order of antibacterial performance of the shutter blades impregnated antibacterial agents is the Ag-embedded nanoTiO2, Chitosan, Xylan. Comprehensiv-ely thought the antibacterial properties and economic index, the optimal concentration of the Ag-embedded nanoTiO2 impregnation solution is 1%.

The isolation of nucleic acids from woody tissue using dimethyl sulfoxide

1972 ◽  
Vol 50 (5) ◽  
pp. 1085-1090 ◽  
Author(s):  
L. V. Gusta ◽  
V. C. Runeckles
Keyword(s):  
Nucleic Acids ◽  
Experimental Evidence ◽  
Dimethyl Sulfoxide ◽  
Ribonuclease Activity ◽  
Woody Tissue ◽  
Bark Tissue ◽  
High Concentrations ◽  
High Degree

A procedure is described for the isolation of nucleic acids from apple bark tissue using dimethyl sulfoxide. Nucleic acids isolated by this method are high in yield, and exhibit a high degree of purity as evidenced by their spectra. Experimental evidence is given to show that extraction of the tissue with dimethyl sulfoxide before the extraction of nucleic acids removes protein and pigments. Little or no ribonuclease activity could be detected in apple bark tissue after extraction with dimethyl sulfoxide. Ribonuclease activity was shown to be strongly inhibited by high concentrations of dimethyl sulfoxide.

scholarly journals Modeled deposition of nitrogen and sulfur in Europe estimated by 14 air quality model systems: evaluation, effects of changes in emissions and implications for habitat protection

2018 ◽  
Vol 18 (14) ◽  
pp. 10199-10218 ◽  
Author(s):  
Marta G. Vivanco ◽  
Mark R. Theobald ◽  
Héctor García-Gómez ◽  
Juan Luis Garrido ◽  
Marje Prank ◽  
...  
Keyword(s):  
Air Quality ◽  
Wet Deposition ◽  
Task Force ◽  
Ecological Impacts ◽  
Model Systems ◽  
Air Quality Model ◽  
Quality Model ◽  
Deposition Rates ◽  
Large Variability ◽  
Quality Models

Abstract. The evaluation and intercomparison of air quality models is key to reducing model errors and uncertainty. The projects AQMEII3 and EURODELTA-Trends, in the framework of the Task Force on Hemispheric Transport of Air Pollutants and the Task Force on Measurements and Modelling, respectively (both task forces under the UNECE Convention on the Long Range Transport of Air Pollution, LTRAP), have brought together various regional air quality models to analyze their performance in terms of air concentrations and wet deposition, as well as to address other specific objectives.This paper jointly examines the results from both project communities by intercomparing and evaluating the deposition estimates of reduced and oxidized nitrogen (N) and sulfur (S) in Europe simulated by 14 air quality model systems for the year 2010. An accurate estimate of deposition is key to an accurate simulation of atmospheric concentrations. In addition, deposition fluxes are increasingly being used to estimate ecological impacts. It is therefore important to know by how much model results differ and how well they agree with observed values, at least when comparison with observations is possible, such as in the case of wet deposition.This study reveals a large variability between the wet deposition estimates of the models, with some performing acceptably (according to previously defined criteria) and others underestimating wet deposition rates. For dry deposition, there are also considerable differences between the model estimates. An ensemble of the models with the best performance for N wet deposition was made and used to explore the implications of N deposition in the conservation of protected European habitats. Exceedances of empirical critical loads were calculated for the most common habitats at a resolution of 100  ×  100 m2 within the Natura 2000 network, and the habitats with the largest areas showing exceedances are determined.Moreover, simulations with reduced emissions in selected source areas indicated a fairly linear relationship between reductions in emissions and changes in the deposition rates of N and S. An approximate 20 % reduction in N and S deposition in Europe is found when emissions at a global scale are reduced by the same amount. European emissions are by far the main contributor to deposition in Europe, whereas the reduction in deposition due to a decrease in emissions in North America is very small and confined to the western part of the domain. Reductions in European emissions led to substantial decreases in the protected habitat areas with critical load exceedances (halving the exceeded area for certain habitats), whereas no change was found, on average, when reducing North American emissions in terms of average values per habitat.

The Preparation of Loaded Photocatalyst for Advanced Treatment of NH3-N in Coking Water

2013 ◽  
Vol 726-731 ◽  
pp. 2829-2832
Author(s):  
Yong Shu Tian ◽  
Run Xin Hou
Keyword(s):  
Photocatalytic Degradation ◽  
Orthogonal Experiment ◽  
Influence Factors ◽  
Advanced Treatment ◽  
Optimum Process ◽  
Process Conditions ◽  
Single Factor ◽  
Clay Brick ◽  
Degradation Rates ◽  
Single Factor Experiment

Photocatalyst of Fe-Sm-Yb modified TiO2 loaded on clay brick was prepared for degradation of NH3-N in coking water. The influence factors of NH3-N degradation rates were discussed by single factor experiment and orthogonal experiment. The optimum process conditions of photocatalytic degradation NH3-N in coking water were confirmed. The results show that NH3-N degradation rates 82.23% were highest in the conditions of pH 6.5, photocatalyst charge of 1.4 g, illumination for 6h, reaction at 55°C, calcination at 500°C.

scholarly journals Hydrological stability and otter trophic diversity: a scale-insensitive pattern?

2008 ◽  
Vol 86 (10) ◽  
pp. 1152-1158 ◽  
Author(s):  
M. Clavero ◽  
J. Prenda ◽  
F. Blanco-Garrido ◽  
M. Delibes
Keyword(s):  
Iberian Peninsula ◽  
Fish Consumption ◽  
Aquatic Ecosystems ◽  
Fish Populations ◽  
Lutra Lutra ◽  
Mediterranean Streams ◽  
Diet Diversity ◽  
Trophic Diversity ◽  
Eurasian Otter ◽  
The Stability

Two recent works related Eurasian otter ( Lutra lutra (L., 1758)) trophic patterns over large areas with the stability of aquatic ecosystems. Higher levels of instability lead to reduced availability and (or) predictability of fish, and consequently, to a decrease in fish consumption by otters. The aim of the present study is to test these macrogeographical patterns in otter diet at regional and local scales. We analysed otter diet in Mediterranean streams in southwestern Iberian Peninsula where clear hydrological stability gradients (related to drainage area or distance to the sea) could be defined. Hydrological stability was directly related to fish consumption and inversely to otter diet diversity in terms of occurrence and biomass, both at regional and local scales. The level of stability of aquatic ecosystems appears to be a critical indirect factor that modulates otter diet through its effects on fish populations. The resulting trophic patterns are maintained from local to macrogeographical scales.

Seasonal variations in black and organic carbon wet and dry deposition rates at SMEAR III station (60oN), Finland

2021 ◽  
Author(s):  
Outi Meinander ◽  
Enna Heikkinen ◽  
Jonas Svensson ◽  
Minna Aurela ◽  
Aki Virkkula ◽  
...  
Keyword(s):  
Organic Carbon ◽  
Black Carbon ◽  
Dry Deposition ◽  
Wet Deposition ◽  
Total Carbon ◽  
Sampling Location ◽  
Atmospheric Measurements ◽  
Deposition Rates ◽  
Wet And Dry Deposition ◽  
Custom Made

<p>Black carbon (BC) and organic carbon (OC, including brown carbon BrC) aerosols in the atmosphere, and their wet and dry deposition, are important for their climatic and cryospheric effects. Seemingly small amounts of BC in snow, of the order of 10–100 parts per billion by mass (ppb), have been shown to decrease its albedo by 1–5 %. Due to the albedo-feedback mechanism, surface darkening accelerates snow and ice melt. In snow, the temporal variability of light absorbing aerosols, such as BC, depends both on atmospheric and cryospheric processes, mostly on sources and atmospheric transport, and dry and wet deposition processes, as well as post-depositional snow processes.</p><p>We started a new research activity on BC and OC wet and dry deposition at Helsinki Kumpula SMEAR III station (60°12 N, 24°57 E, Station for Measuring Ecosystem-Atmosphere Relations, https://www.atm.helsinki.fi/SMEAR/index.php/smear-iii). The work included winter, spring, summer and autumn deposition samples during January 2019 - June 2020 (sampling is currently on hold). In winter, wet deposition consisted of snowfall and rainwater samples. Dry deposition samples were separately collected in 2020. For sample collection, a custom-made device, including a heating-system, was applied. The samples were analyzed using the OCEC analyzer of the Finnish Meteorological Institute’s aerosol laboratory, Helsinki, Finland. The special features in our deposition data are: </p><ul><li>seasonal BC, OC, and TC (total carbon, the sum of BC and OC) deposition data for an urban background station at 60 <sup>o</sup>N</li> <li>precipitation received as either water or snow  </li> <li>dry deposition samples included (only in 2020)</li> <li>data as wet and dry deposition rates [concentration/time/area]</li> <li>simultaneous atmospheric measurements of the SMEAR III station</li> </ul><p>Since our deposition samples are collected manually, the data are non-continuous, yet they allow us to provide deposition rates. Such data can be utilized in various modeling approaches including, for example, climate and long-range transport and deposition modeling. According to our knowledge, these data are the first BC (determined as elemental carbon, EC), OC and TC wet and dry deposition data to represent Finland. Our sampling location, north of 60 deg. N, can be useful for other high-latitude studies and Arctic assessments, too.</p><p><em>Acknowledgements. We gratefully acknowledge support from the Academy of Finland NABCEA-project of Novel Assessment of Black Carbon in the Eurasian Arctic (no. 296302) and the Academy of Finland Flagship funding (grant no. 337552).</em></p>

Preparation and Characteristics of the Micro/Nano Fibrils from the Wheat-Straw Treated by Enzyme

2013 ◽  
Vol 432 ◽  
pp. 20-24
Author(s):  
Cong Liu ◽  
Yang Zhang ◽  
Yong Su
Keyword(s):  
Fourier Transform ◽  
Wheat Straw ◽  
Treatment Condition ◽  
Enzyme Treatment ◽  
Single Factor ◽  
Ultrasonic Dispersion ◽  
X Ray ◽  
Transmission Electron ◽  
Infrared Spectrometer ◽  
Single Factor Experiment

Single-factor experiment was applied to get the optimum enzyme treatment condition: water bath in the oscillation trough at the frequency of 80 in 50°C with enzyme usage 35 IU/g for 48h. Transmission electron microscope (TEM), laser granularity distributing machine, Fourier transform infrared spectrometer (FTIR) and X-ray diffractor (XRD) were used to analyze the product with enzyme treatment. Observing by TEM, we could see large volume of micro/nanofibrils had gathered together, while fibre was 100-300 nm long and far less than 100nm radial, meeting the requirement of micro/nanofibrils. Being analyzed with laser granularity distributing machine, part of the product had reached the micro/nanolevel. Analyzing by FTIR, we can conclude that after enzyme treatment and ultrasonic dispersion cellulose had no change in functional groups. From the crystallinity atlas, we find the crystallinity of wheat-straw micro/nanofibrils improved from 65.55% to 72.99%, showing that cellulose enzyme destroyed the non-crystallizing field effectively

Sign in / Sign up

Export Citation Format

Share Document