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Genetic Analysis of Black Spruce (Picea mariana) Populations from Dry and Wet Areas of a Metal-Contaminated Region in Ontario (Canada)
2011
Dobrzeniecka, Sylwia | Nkongolo, Kabwe K. | Michael, Paul | Mehes-Smith, Melanie | Beckett, Peter
Genetic variation and genetic structure of black spruce (Picea mariana L.) populations growing in wet land (lowlands) and dry lands (uplands) with different levels of metal contaminations were analyzed using ISSR. Polymorphic loci (P%) ranged from 65% to 90% with a mean of 75%. Nei’s gene diversity (h) varied from 0.264 to 0.359 with a mean of 0.310, and Shannon’s index (I) ranged from 0.381 to 0.524 with a mean of 0.449. The level of genetic variation was higher in populations from wet lands than those from dry lands. Variation within populations accounts for most of total genetic variation. The genetic distance among the black spruce (P. mariana) populations ranged from 0.171 to 0.351. The present study indicates that genetic variation and long-term exposure to metals (more than 30Â years) are not associated. Cytological analysis of black spruce seeds from metal-contaminated and -uncontaminated areas showed normal mitotic behavior during prophase, metaphase, anaphase, and telophase.
Afficher plus [+] Moins [-]Behaviour and Growth of Chironomus riparius Meigen (Diptera: Chironomidae) under Imidacloprid Pulse and Constant Exposure Scenarios
2011
Azevedo-Pereira, Henrique M. V. S. | Lemos, Marco F. L. | Soares, Amadeu M. V. M.
Imidacloprid is a new insecticide that mimics nicotine, combining its insecticidal activity with a reduced persistence in the environment. The toxicity of imidacloprid to Chironomus riparius Meigen using the formulated product Confidor® from Bayer®, in pulse and continuous exposure, was evaluated in this study. The behavioural response of the midge after toxicant exposure using an online biomonitor was also investigated. Early second-instar C. riparius larvae were exposed in either constant (10Â days) or pulse (4Â days, followed by 6Â days post exposure in clean medium) conditions. Imidacloprid constant exposure resulted in a decrease in growth and impairment of the behavioural pattern of the midge larvae. Pulsed exposure followed by a recovery period revealed a recovery of midge physiological conditions, by reaching a stabilisation of normal behavioural activities and growth among treatments. Moreover, ventilation showed to be a more sensitive parameter by revealing a faster recovery than locomotion. Behaviour alterations may weaken the ability to escape from predators, and reduce food acquisition with consequent growth impairment. These effects may have an impact at the population and community level.
Afficher plus [+] Moins [-]Ultrasonic Enhanced Desorption of DDT from Contaminated Soils
2011
Thangavadivel, Kandasamy | Megharaj, Mallavarapu | Smart, Roger St. C. | Lesniewski, Peter J. | Bates, Darren | Naidu, R.
In this study, using high-power low-frequency ultrasound, heated slurries with anionic surfactant sodium dodecyl sulfate (SDS) were treated to enhance desorption of DDT from soils with high clay, silt, and organic matter content and different pH (5.6–8.4). The results were compared with DDT extracted using a strong solvent combination as reference. Slurry ranges from 5 to 20Â wt.% were studied. For a soil slurry (10Â wt.%) at pHÂ 6.9 with 0.1% v/v SDS surfactant heated to 40°C for 30Â min, desorption was above 80% in 30Â s using 20Â kHz, 932 W/L ultrasonic intensity without solvent extraction. Other soils gave lower desorption efficiency in the range 40–60% after 30Â s ultrasonic treatment. The percentage of organic matter, dissolved organic carbon, soil surface area, clay and silt percentage, and soil pH level were the key parameters influencing variations in desorption of DDT in the three soils in similar experimental conditions. DDT dissolution in SDS and soil organic matter removal employing the ultrasonic-enhanced organic matter roll-up mechanism emerged as the two best possible methods of DDT desorption. The method offers a practical, potentially low-cost alternative to high volume, costly, hazardous solvent extraction of DDT.
Afficher plus [+] Moins [-]Phytoavailability of Toxic Heavy Metals and Productivity in Wheat Cultivated Under Residual Effect of Fertilization in Soybean Culture
2011
Gonçalves, Affonso Celso, Jr | Nacke, Herbert | Schwantes, Daniel | Nava, Ivair André | Strey, Leonardo
Achieving high productivity in agriculture is increasingly needed and requested; however, this activity should be performed in a sustainable and rational way. The use of micronutrients in the fertilization of the most diverse cultures is becoming a common practice on farms, but it is important to conduct studies in relation to fertilizers used for this supplement, including raw materials with which they are produced. Therefore, this study aimed to evaluate the phytoavailability of nutrients and toxic heavy metals Cd, Pb, and Cr; productivity; and yield components in wheat sown in soil with residue of N/P2O5/K2Oâ+âZn-based fertilizer applied in previous crop. Treatments consisted of residual fertilization of five forms arranged in two doses (D1â=â300 kg ha−1 and D2â=â600 kg ha−1). The five types of fertilization were composed of formulated N/P2O5/K2O and the variation of different Zn sources. In the assessment of phytoavailability were determined levels of K, Ca, Mg, Cu, Mn, Zn, Fe, Cd, Pb, and Cr in wheat leaves. The results show that the residual effect of fertilization was not enough for there being difference between treatments at both doses used; however, it was found that the fertilizers used to Zn supply provided residual effect, providing significant levels of Pb and Cr for wheat plants.
Afficher plus [+] Moins [-]Geochemical Characterization of Organic Pollutants in Effluents Discharged from Various Industrial Sources to Riverine Systems
2011
Botalova, Oxana | Schwarzbauer, Jan
The detailed characterization of the organic composition of industrial effluents discharged from various industrial branches and the distribution of the emitted pollutants in the surface waters in North Rhine-Westphalia have been done with the use of non-target screening analyses. Based on the characterization of molecular structures of wastewater constituents, their quantification as well as the available information on their origin and industrial applications, the identification of typical organic representatives for petrochemical and food effluents has been performed. Among a wide range of hydrocarbons detected in the petrochemical effluents, several novel organic wastewater constituents have been found for the first time. In the effluents from paper production plant, potential industrial indicators were distinguished, such as resin acids (abietic and dehydroabietic acids) and photoinitiators (Irgacure 184). The monitoring of the behaviour of certain environmentally relevant and newly described pollutants in the contaminated river systems allowed the identification of several industrial site-specific markers. Particularly, 2-(chloromethyl)-1,3-dioxolane, an unknown contaminant, exclusively found in the effluents from a chemical production complex, was present in the river under discharge at high concentrations downstream the contamination source. The comprehensive and detailed evaluation of the anthropogenic markers in the industrial effluents is a promising tool for the environmental assessment of industrial emissions, especially if accompanied with toxicological and ecotoxicological investigations of novel environmental contaminants.
Afficher plus [+] Moins [-]Mercury (Hg) Transport in a High Arctic River in Northeast Greenland
2011
Rigét, Frank | Tamstorf, Mikkel P. | Larsen, Martin M. | Søndergaard, Jens | Asmund, Gert | Falk, Julie Maria | Sigsgaard, Charlotte
In a warming climate, mercury (Hg) pathways in the Arctic can be expected to be affected. The Hg transport from the high arctic Zackenberg River Basin was assessed in 2009 in order to describe and estimate the mercury transported from land to the marine environment. A total of 95 water samples were acquired and filtered (0.4 μm pore size), and Hg concentrations were determined in both the filtered water and in the sediment. A range of other elements were also measured in the water samples. Hg concentrations in the filtered water were in general highest in the beginning of the season when the water came mainly from melted snow. THg concentrations in the sediment were in general relatively constant or slightly decreasing until mid-August, where after the concentrations increased. A principal component analysis separated the samples into spring, summer and autumn samples indicating seasonal characteristics of the patterns of element concentrations. The total amount of Hg in the sediment transported was estimated to 2.6 kg. Approximately 60% of the sediment-transported Hg occurred during a 24-h flood in the beginning of August caused by a glacial lake outburst flood. The total amount of transported dissolved Hg was estimated to 46 g, and 13% of this transport occurred during the 24-h flood. If it is assumed that the Hg transport by Zackenberg River is representative for the general glacial rivers in East Greenland, the total Hg transport into the North Atlantic from Greenland alone is approximately 4.6 tons year−1 with an estimated annual freshwater discharge of â¼440 km3.
Afficher plus [+] Moins [-]Tannin-Based Coagulants in the Depuration of Textile Wastewater Effluents: Elimination of Anthraquinonic Dyes
2011
Beltrán-Heredia, Jesus | Sánchez-Martín, Jesus | Jiménez-Giles, Mercedes
Two tannin-based coagulants have been tested on anthraquinonic dye elimination from aqueous solutions. Acquapol S5T, derived from Acacia mearnsii de Wild, and Silvafloc, derived from Schinopsis balansae, were found to be excellent agents in the destabilization of Alizarin Violet 3R dye and its elimination through coagulation from textile effluents. Both coagulants showed that high affinity to the dye molecule in a wide pH range and q values reaches significant levels (up to 0.5 mg mg − 1) with reasonable low coagulant doses. Dye–coagulant system presented a consistent behavior if studied under the statistical perspective of a design of experiments, where initial dye concentration and coagulant dose were the operating variables. Finally, both coagulants seemed to follow a predictable theoretical model under the Langmuir hypothesis with an accurate adjusted r 2 coefficient above 0.9.
Afficher plus [+] Moins [-]Deposition Rate and Chemical Composition of the Aeolian Dust from a Bare Saline Playa, Ebinur Lake, Xinjiang, China
2011
Liu, Dongwei | Abuduwaili, Jilili | Lei, Jiaqiang | Wu, Guangyang
An ongoing project monitors saline dust transportation and accumulation in the Western Junggar Basin to determine the rate and chemical composition of dust inputs to soils and their impact on snow/ice melt and vegetation degradation of the surrounding areas. The 1-year record from ten dust trap sites in the Ebinur region of northwest China reveals that yearly deposition rates fluctuate strongly between different sampling sites. The mass accumulation rates (fluxes) of the dust, including water-soluble solutes and trace element, range from 79 to 381 g m−2 year−1. With increasing distance from the dry lake bed, dust deposition gradually decreases. The salinity of the dust ranges from about 43 to 185 g kg−1 and the mass-soluble salt fluxes range from 4 to 61 g m−2 year−1. The types of water-soluble salt are different at different sampling sites. In all samples, the major types of water-soluble salts in the dust are sulfates and chlorides. Sulfate and chloride are the major anions while sodium and calcium are the main cations, and nitrate was not found in any dust samples. Potentially toxic trace elements such as Cd, Cr, Pb, Mn, As, Cu, and Ni are present in all samples, with high levels of Cr, Pb, Mn, Cu, and Ni. The dust is a chemical dust in that it consists of dense fine sulfates, chlorides and potentially toxic elements, and causes serious air pollution, resulting in soil salinization and vegetation degradation and accelerating snow/ice melt.
Afficher plus [+] Moins [-]Use of Granular Bentonite in the Removal of Mercury (II), Cadmium (II) and Lead (II) from Aqueous Solutions
2011
Fernández-Nava, Yolanda | Ulmanu, Mihaela | Anger, Ildiko | Marañón, Elena | Castrillón, Leonor
Granular bentonite has been assessed regarding its capacity to remove Hg(II), Cd(II) and Pb(II) from aqueous solutions. Sorption capacities, kinetics and the dependence of the sorption process on pH were determined. Fractional power, pseudo-first-order, pseudo-second-order and intra-particle diffusion equations were used to model the kinetics of metal adsorption. The pseudo-second-order model showed the best fit to experimental data. Different two-parameter sorption isotherm models (Langmuir, Freundlich, Temkin and Dubinin–Radushkevich) were used to fit the equilibrium data. Freundlich's isotherm model gave the best fit to experimental data. The selectivity of granular bentonite towards these metals is Pb(II) > Cd(II) > Hg(II). The adsorption capacities of granular bentonite towards the metals expressed in milligramme metal per gramme granular bentonite are 19.45, 13.05 and 1.7 for Pb(II), Cd(II) and Hg(II), respectively (for an initial concentration of 100 mg metal/L).
Afficher plus [+] Moins [-]Fluctuating Asymmetry of Chironomus spp. (Diptera: Chironomidae) Larvae in Association with Water Quality and Metal Pollution in Permatang Rawa River in the Juru River Basin, Penang, Malaysia
2011
Al-Shami, Salman Abdo | Che Salmah, Mad Rawi | Abu Hassan Ahmad, | Siti Azizah Mohd Nor,
The levels of fluctuating asymmetry [random differences between symmetric organismal traits, fluctuating asymmetry (FA)] in the fourth instar of Chironomus spp. larvae inhabiting an agrochemical polluted river [Permatang Rawa River (PRR)] in the Juru River Basin, northeastern peninsular Malaysia, were measured. The PRR receives waters primarily from adjacent rice fields which are exposed to fertilizer and pesticide residues. Samples of larvae, water, and sediments were collected monthly from November 2007 to June 2008. In situ measurements of water pH and dissolved oxygen were made at three sampling locations along the river. Monthly water and benthic sediment collections were also conducted for the following laboratory water analyses: biological oxygen demand (BOD), chemical oxygen demand (COD), total suspended solids (TSS), and ammonium-N content. Non-residual metals in the sediment samples were also analyzed. The water quality index (WQI) of the PRR was also calculated. This study attempted to relate FA levels based on selected traits of Chironomus spp. larval head capsule (mentum width and first and second antennal segment length) to water quality and sediment heavy metal contamination in the PRR. All monthly measurements of FA levels including transcriptors (FA10a, FA4a, ME3, and ME1) and indices [FA, absolute asymmetry (AbsFA), and composite fluctuating asymmetry (CFA)] were calculated. The ordination model of redundancy analysis showed that the dissolved oxygen and water quality in the river expressed as WQI were negatively correlated with all FA indices (FA, AbsFA, and CFA) of the larval mentum width and length of antennal segments I and II. The water pH, BOD, and COD and sediment Cu positively influenced the FA incidence in the larval mentum. The FA indices of the antennal segment I were positively correlated with the increase in the levels of water pH, ammonium-N, BOD, and COD. The FA indices, especially CFA, were sensitive to the water pH and ammonium-N and sediment contaminated by Mn, Cu, and Zn. The FA levels calculated as FA indices of the larval antennal segment II length were positively correlated with water TSS and sediment Mn, Cu, Zn, and Ni. This study revealed that the river water quality and heavy metal contamination affect developmental stability in Chironomus spp. larvae. The FA indices of different structures in the Chironomus spp. larval head capsule could be used as bioindicators for water and sediment pollution.
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