scholarly journals Sex inversion in the Black Sea mussel Mytilus galloprovincialis Lamarck, 1819 under the influence of heavy metals

2019 ◽  
Vol 4 (3) ◽  
pp. 104-106
Author(s):  
N. S. Chelyadina ◽  
M. A. Popov ◽  
N. V. Pospelova ◽  
L. L. Smirnova
Keyword(s):  
Heavy Metals ◽  
Natural Experiment ◽  
Mytilus Galloprovincialis ◽  
Ion Concentration ◽  
The Black Sea ◽  
Female Mortality ◽  
Natural Experiments ◽  
Sexual Structure ◽  
Sex Inversion ◽  
Post Spawning

Heavy metals may be one of the factors causing a change in sexual structure in the settlements of mussel Mytilus galloprovincialis Lam. cultivated on the Sevastopol seaside. The aim of the work was to study the influence of Zn+2, Cd+2, Pb+2, Hg+2, Cu+2 ions on the sex inversion of cultivated mussels during spring post spawning of gonads. Chronic intoxication of female mussel at ion concentration of 2 MPC was carried out for a month in laboratory conditions. After 3 months of a natural experiment, the sex of each mollusc was individually examined by the method of visual study of gonad smears. The sex inversion of the females occurred under the influence of all heavy metals. The maximum shares of males were observed after the influence of Cu+2 and Pb+2 – 65 and 52 %, respectively. Both laboratory and natural experiments showed high toxic effect of Cu+2 and Hg+2 ions, with female mortality reaching 33 and 13 %, respectively.

scholarly journals SEX INVERSION IN CULTIVATED MUSSELS MYTILUS GALLOPROVINCIALIS LAM. (CRIMEA, BLACK SEA) UNDER INFLUENCE OF EXTERNAL ENVIRONMENTAL FACTORS

2018 ◽  
Vol 19 ◽  
pp. 26-31
Author(s):  
Natalya Chelyadina ◽  
Natalya Pospelova ◽  
Mark Popov ◽  
Ludmila Smyrnova ◽  
Irina Kharchuk ◽  
...  
Keyword(s):  
Environmental Factors ◽  
Sex Ratio ◽  
Black Sea ◽  
Diesel Fuel ◽  
Hormonal Regulation ◽  
Anthropogenic Impact ◽  
Mytilus Galloprovincialis ◽  
The Black Sea ◽  
Sex Inversion ◽  
Anionic Detergents

In the last decade, there has been a shift in the sex ratio of the mussel Mytilus galloprovincialis in the Black Sea towards increase of males. In modern literature, focus is mainly on mechanisms of sex inheritance in mussels and hormonal regulation of the reproduction, and there is no information on sex inversion in M. galloprovincialis under the influence of environmental factors. The goal of this work is to establish the fact of sex change in mussels cultivated near the coast of Crimea under the influence of some external environmental factors. We establish that mussels change sex from female to male, but some specimens become hermaphrodites, with their fraction reaching 13%. Under unfavorable environmental conditions, mussel females change sex, and their mortality rises up to 69%. In water areas subject to anthropogenic impact, the proportion of sex inversion in the mollusks may be as high as 58%. The influence of various adverse   environmental factors on sex inversion in mussel females is unequal, and its strength decreases in the following order: diesel fuel > hypoxia > anionic detergents > starvation.

Natural “Natural Experiments” in Economics

2000 ◽  
Vol 38 (4) ◽  
pp. 827-874 ◽  
Author(s):  
Mark R Rosenzweig ◽  
Kenneth I Wolpin
Keyword(s):  
Natural Experiment ◽  
Recent Literature ◽  
Economic Models ◽  
Empirical Knowledge ◽  
Natural Experiments ◽  
Simple Economic

The recent literature exploiting natural events as “natural experiment” instruments is reviewed to assess to what extent it has advanced empirical knowledge. A weakness of the studies that adopt this approach is that the necessary set of behavioral, market, and technological assumptions made by the authors in justifying their interpretations of the estimates is often absent. The methodology and findings from twenty studies are summarized and simple economic models are used to elucidate the implicit assumptions made by the authors and to demonstrate the sensitivity of the interpretations of the findings to the relaxation of some of these assumptions.

Seasonal variations of heavy metals content in mussels (Mytilus galloprovincialis) from Cala Iris offshore (Northern Morocco)

2018 ◽  
Vol 137 ◽  
pp. 688-694 ◽  
Author(s):  
Ghizlane Azizi ◽  
Mostafa Layachi ◽  
Mustapha Akodad ◽  
David R. Yáñez-Ruiz ◽  
Antonio Ignacio Martín-García ◽  
...  
Keyword(s):  
Heavy Metals ◽  
Seasonal Variations ◽  
Mytilus Galloprovincialis

scholarly journals Platelet activating factor raises intracellular calcium ion concentration in macrophages.

1986 ◽  
Vol 103 (2) ◽  
pp. 439-450 ◽  
Author(s):  
G W Conrad ◽  
T J Rink
Keyword(s):  
Heavy Metals ◽  
Intracellular Calcium ◽  
Calcium Ion ◽  
Platelet Activating Factor ◽  
Ion Concentration ◽  
Early Event ◽  
Acetoxymethyl Ester ◽  
Intracellular Calcium Ion ◽  
The Times ◽  
Calcium Ion Concentration

Peritoneal cells from thioglycollate-stimulated mice were allowed to adhere to coverglasses for 2 h to give a dense monolayer of adherent cells greater than 95% of which were macrophages. After incubation with the tetra-acetoxymethyl ester of quin2, coverglasses were rinsed with Ca2+-free saline, oriented at a 45 degree angle in square cuvettes containing a magnetically driven stir bar, and analyzed for changes in quin2 fluorescence in a spectrofluorimeter. Such fluorescence, taken as an indication of intracellular calcium ion concentration ([Ca2+]i), increased as exogenous calcium ion concentration ([Ca2+]o) was raised to 1 mM. At [Ca2+]o approximately equal to 10 microM, [Ca2+]i = 72 +/- 14 nM (n = 26); at [Ca2+]o = 1 mM, [Ca2+]i = 140-220 nM, levels not increased by N, N, N', N'-tetrakis (2-pyridylmethyl) ethylenediamine, a membrane-permeant chelator of heavy metals than can quench quin2. Addition of mouse alpha + beta fibroblast interferon, lipopolysaccharide, thrombin, collagen, vasopressin, ADP, compound 48/80, or U46619 did not change [Ca2+]i. However, addition of platelet activating factor (PAF) (2-20 ng/ml) raised [Ca2+]i by 480 nM within 1 min if [Ca2+]o = 1 mM. In the presence of 5 mM EGTA, PAF raised [Ca2+]i by 25 nM. This suggests that PAF causes influx of exogenous Ca2+, as well as releasing some Ca2+ from intracellular stores. Consistent with these results, when PAF was added to 1 mM Ca2+ in the presence of 100 microM Cd2+ or Mn2+ to block Ca2+ influx, [Ca2+]i increased by only intermediate amounts; at the times of such dampened peak response, [Ca2+]i could be raised within 1 min to normal PAF-stimulated levels by chelation of the exogenous heavy metals with diethylenetriaminepentaacetic acid. Normal PAF responses were observed in the presence of indomethacin. The lowest dose of PAF observed to raise [Ca2+]i was 0.1 ng/ml. Response of [Ca2+]i to 2-20 ng/ml PAF was transient, and second applications had no effect. The PAF response also was seen in cell suspensions. These results suggest that an increase in [Ca2+]i may be an early event in PAF activation of macrophages.

scholarly journals Biosorption of Cadmium by Fucus spiralis

2004 ◽  
Vol 1 (3) ◽  
pp. 180 ◽  
Author(s):  
Manuel Esteban Sastre de Vicente ◽  
Roberto Herrero ◽  
Pablo Lodeiro ◽  
Bruno Cordero
Keyword(s):  
Heavy Metals ◽  
Metal Removal ◽  
Heavy Metal Removal ◽  
Biological Materials ◽  
Ion Concentration ◽  
Adsorption Parameters ◽  
Solution Ph ◽  
Biosorption Process ◽  
Fucus Spiralis ◽  
Biosorption Kinetics

Environmental Context. Conventional processes for the removal of heavy metals from wastewaters generally involves chemical precipitation of metals (changing the pH) followed by a period to allow the metal precipitates to settle and be separated. These processes are inefficient when the metals are at a low concentration and still demand handling and disposal of toxic metal sludges. An alternative method for heavy metal removal is adsorption onto a biological material, biosorption. The biological materials, including agricultural byproducts, bacteria, fungi, yeast, and algae, all which take up heavy metals in substantial quantities, are relatively inexpensive, widely available, and from renewable sources. However, biological materials are complex and the active mechanisms often unclear. Abstract. Cadmium biosorption properties of nonliving, dried brown marine macroalga Fucus spiralis from Galician coast (northwest Spain) have been investigated. The biosorption capacity of the alga strongly depends on solution pH; the uptake is almost negligible at pH ≤ 2 and reaches a plateau at around pH 4.0. Cadmium biosorption kinetics by F. spiralis is relatively fast, with 90% of total adsorption taking place in less than one hour. A pseudo second order mechanism has been proved to be able to predict the kinetic behaviour of the biosorption process. The effect of initial cadmium ion concentration, alga dose, solution pH, and temperature on the biosorption kinetics has been studied. The Langmuir, Freundlich, Langmuir–Freundlich, and Tóth isotherms were used to fit the experimental data and to find out the adsorption parameters. Acid–base properties of the alga have been studied potentiometrically in order to calculate the number of acidic groups and the apparent pK value by using Katchalsky model. The pK obtained is comparable with typical values associated to the ionization of carboxyl groups of alginates, supporting the implication of these groups in the biosorption process.

Mobility of Ra-226 and Heavy Metals (U, Th and Pb) From Pyritic Uranium Mine Tailings Under Sub-Aqueous Disposal Conditions

2011 ◽  
Author(s):  
Nand K. Dave´
Keyword(s):  
Heavy Metals ◽  
Surface Water ◽  
Mine Tailings ◽  
Ion Concentration ◽  
Uranium Mine ◽  
Acid Generation ◽  
Shallow Zone ◽  
Acidic Conditions ◽  
Waste Repositories

Laboratory lysimeter studies were undertaken to evaluate the leaching characteristics and mobility of Ra-226 and other heavy metals (U, Th and Pb) from pyritic uranium mine tailings under sub-aqueous disposal conditions for assessing the long-term radiological stability of such waste repositories. The experiments were conducted using three types of un-oxidized tailings: fine, coarse and gypsum depleted mill total tailings. The results showed that Ra-226 was leached from surface of the submerged tailings and released to both surface water and shallow zone pore water during initial low sulphate ion concentration of the surface water cover in all three cases. The release of Ra-226 was further enhanced with the onset of weak acidic conditions in the surface water covers of both coarse and gypsum depleted mill total tailings. With additional acid generation and increasing sulphate and iron concentrations, the dissolved Ra-226 concentrations in the water covers of these tailings gradually decreased back to low levels. Pb was also leached and mobilized with the development of moderate acidic conditions at the surface of the submerged coarse and gypsum deplete tailings. No leaching of U and Th was observed.

scholarly journals Effective Heavy Metals Removal from Water Using Nanomaterials: A Review

Processes ◽  
2020 ◽  
Vol 8 (6) ◽  
pp. 645 ◽  
Author(s):  
Mohamed A. Tahoon ◽  
Saifeldin M. Siddeeg ◽  
Norah Salem Alsaiari ◽  
Wissem Mnif ◽  
Faouzi Ben Rebah
Keyword(s):  
Heavy Metals ◽  
Cost Effective ◽  
Ion Concentration ◽  
Wastewater Remediation ◽  
Toxic Heavy Metals ◽  
Surrounding Environment ◽  
Metals Removal ◽  
Physicochemical Factors ◽  
Magnetic Metal ◽  
High Threat

The discharge of toxic heavy metals including zinc (Zn), nickel (Ni), lead (Pb), copper (Cu), chromium (Cr), and cadmium (Cd) in water above the permissible limits causes high threat to the surrounding environment. Because of their toxicity, heavy metals greatly affect the human health and the environment. Recently, better remediation techniques were offered using the nanotechnology and nanomaterials. The attentions were directed toward cost-effective and new fabricated nanomaterials for the application in water/wastewater remediation, such as zeolite, carbonaceous, polymer based, chitosan, ferrite, magnetic, metal oxide, bimetallic, metallic, etc. This review focused on the synthesis and capacity of various nanoadsorbent materials for the elimination of different toxic ions, with discussion of the effect of their functionalization on the adsorption capacity and separation process. Additionally, the effect of various experimental physicochemical factors on heavy metals adsorption, such as ionic strength, initial ion concentration, temperature, contact time, adsorbent dose, and pH was discussed.

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