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Sandhopper solar orientation as a behavioural biomarker of trace metals contamination Texte intégral
2009
Ungherese, Giuseppe | Ugolini, Alberto
Although many studies have focused on trace metals accumulation, investigations of talitrid amphipods as biomarkers are rare. This study explores the possibility of using the solar orientation capacity of Talitrus saltator as a behavioural marker of exposure to two essential (Cu and Zn) and two non-essential (Cd and Hg) metals. LC50 analyses performed before the solar orientation tests showed that the 72 h LC50 for Hg was 0.02 ppm while the 96 h LC50 values for Cu, Cd and Zn were 13.28 ppm, 27.66 ppm, and 62.74 ppm, respectively. The presence of metals in seawater affects the solar orientation capacity of T. saltator in a concentration-dependent manner and according to the toxicity ranking of the metals (Hg > Cu > Cd > Zn). Therefore, the solar orientation capacity of T. saltator seems to be a promising behavioural marker for exposure to trace metals. Solar orientation capacity is a promising behavioural marker for exposure to trace metals in sandhoppers.
Afficher plus [+] Moins [-]Adsorption and transformation of selected human-used macrolide antibacterial agents with iron(III) and manganese(IV) oxides Texte intégral
2009
Feitosa-Felizzola, Juliana | Hanna, Khalil | Chiron, Serge
The adsorption/transformation of two members (clarithromycin and roxithromycin) of the macrolide (ML) antibacterial agents on the surface of three environmental subsurface sorbents (clay, iron(III) and manganese(IV) oxy-hydroxides) was investigated. The adsorption fitted well to the Freundlich model with a high sorption capacity. Adsorption probably occurred through a surface complexation mechanism and was accompanied by slow degradation of the selected MLs. Transformation proceeded through two parallel pathways: a major pathway was the hydrolysis of the cladinose sugar, and to a lesser extent the hydrolysis of the lactone ring. A minor pathway was the N-dealkylation of the amino sugar. This study indicates that Fe(III) and Mn(IV) oxy-hydroxides in aquatic sediments may play an important role in the natural attenuation of MLs. Such an attenuation route yields a range of intermediates that might retain some of their biological activity. Iron(III) and manganese(IV) oxy-hydroxides in aquatic sediments may play an important role in the natural attenuation of macrolide antibacterial agents.
Afficher plus [+] Moins [-]Production and sedimentation of peptide toxins nodularin-R and microcystin-LR in the northern Baltic Sea Texte intégral
2009
Kankaanpää, Harri T. | Sjövall, Olli | Huttunen, Maija | Olin, Miikka | Karlsson, Krister | Hyvärinen, Kirsi | Sneitz, Laura | Härkönen, Janne | Sipiä, Vesa O. | Meriluoto, Jussi A.O.
This seven-year survey was primarily targeted to quantification of production of nodularin-R (NOD-R), a cyclic pentapeptide hepatotoxin, in Baltic Sea cyanobacteria waterblooms. Additionally, NOD-R and microcystin-LR (MC-LR; a cyclic heptapeptide toxin) sedimentation rates and NOD-R sediment storage were estimated. NOD-R production (70-2450 μg m⁻³; 1 kg km⁻² per season) and sedimentation rates (particles; 0.03-5.7 μg m⁻² d⁻¹; 0.3 kg km⁻² per season) were highly variable over space and time. Cell numbers of Nodularia spumigena did not correlate with NOD-R quantities. Dissolved NOD-R comprised 57-100% of total NOD-R in the predominantly senescent, low-intensity phytoplankton blooms and seston. Unprecedentedly intensive MC-LR sedimentation (0.56 μg m⁻² d⁻¹) occurred in 2004. Hepatotoxin sedimentation rates highly exceeded those of anthropogenic xenobiotics. NOD-R storage in surficial sediments was 0.4-20 μg kg⁻¹ (0.1 kg km⁻²). Loss of NOD-R within the chain consisting of phytoplankton, seston and soft sediments seemed very effective. Production of nodularin-R in pelagic Baltic Sea takes place in a scale of up to kilograms per square kilometre.
Afficher plus [+] Moins [-]Molecular characterization of copper in soils using X-ray absorption spectroscopy Texte intégral
2009
Strawn, Daniel G. | Baker, Leslie L.
Bioavailability of Cu in the soil is a function of its speciation. In this paper we investigated Cu speciation in six soils using X-ray absorption near edge structure (XANES), extended X-ray absorption fine structure (EXAFS), and synchrotron-based micro X-ray fluorescence (μ-XRF). The XANES and EXAFS spectra in all of the soils were the same. μ-XRF results indicated that the majority of the Cu particles in the soils were not associated with calcium carbonates, Fe oxides, or Cu sulfates. Principal component analysis and target transform of the XANES and EXAFS spectra suggested that Cu adsorbed on humic acid (HA) was an acceptable match. Thus it appears that Cu in all of the soils is primarily associated with soil organic matter (SOM). Theoretical fitting of the molecular structure in the soil EXAFS spectra revealed that the Cu in the soils existed as Cu atoms bound in a bidentate complex to O or N functional groups.
Afficher plus [+] Moins [-]Characterization of aluminium-based water treatment residual for potential phosphorus removal in engineered wetlands Texte intégral
2009
Babatunde, A.O. | Zhao, Y.Q. | Burke, A.M. | Morris, M.A. | Hanrahan, J.P.
Aluminium-based water treatment residual (Al-WTR) is the most widely generated residual from water treatment facilities worldwide. It is regarded as a by-product of no reuse potential and landfilled. This study assessed Al-WTR as potential phosphate-removing substrate in engineered wetlands. Results indicate specific surface area ranged from 28.0 m² g⁻¹ to 41.4 m² g⁻¹. X-ray Diffraction, Fourier transform infrared and energy-dispersive X-ray spectroscopes all indicate Al-WTR is mainly composed of amorphous aluminium which influences its phosphorus (P) adsorption capacity. The pH and electrical conductivity ranged from 5.9 to 6.0 and 0.104 dS m⁻¹ to 0.140 dS m⁻¹ respectively, showing that it should support plant growth. Batch tests showed adsorption maxima of 31.9 mg P g⁻¹ and significant P removal was achieved in column tests. Overall, results showed that Al-WTR can be used for P removal in engineered wetlands and it carries the benefits of reuse of a by-product that promotes sustainability.
Afficher plus [+] Moins [-]Widespread waterborne pollution in central Swedish lakes and the Baltic Sea from pre-industrial mining and metallurgy Texte intégral
2009
Bindler, Richard | Renberg, Ingemar | Rydberg, Johan | Andrén, Thomas
Metal pollution is viewed as a modern problem that began in the 19th century and accelerated through the 20th century; however, in many parts of the globe this view is wrong. Here, we studied past waterborne metal pollution in lake sediments from the Bergslagen region in central Sweden, one of many historically important mining regions in Europe. With a focus on lead (including isotopes), we trace mining impacts from a local scale, through a 120-km-long river system draining into Mälaren - Sweden's third largest lake, and finally also the Baltic Sea. Comparison of sediment and peat records shows that pollution from Swedish mining was largely waterborne and that atmospheric deposition was dominated by long-range transport from other regions. Swedish ore lead is detectable from the 10th century, but the greatest impact occurred during the 16th-18th centuries with improvements occurring over recent centuries, i.e., historical pollution > modern industrial pollution. Pollution in Sweden during AD 900-1900 was often greater than modern industrial pollution.
Afficher plus [+] Moins [-]Interacting effects of sulphate pollution, sulphide toxicity and eutrophication on vegetation development in fens: A mesocosm experiment Texte intégral
2009
Geurts, Jeroen J.M. | Sarneel, Judith M. | Willers, Bart J.C. | Roelofs, Jan G.M. | Verhoeven, Jos T.A. | Lamers, Leon P.M.
Both eutrophication and SO₄ pollution can lead to higher availability of nutrients and potentially toxic compounds in wetlands. To unravel the interaction between the level of eutrophication and toxicity at species and community level, effects of SO₄ were tested in nutrient-poor and nutrient-rich fen mesocosms. Biomass production of aquatic and semi-aquatic macrophytes and colonization of the water layer increased after fertilization, leading to dominance of highly competitive species. SO₄ addition increased alkalinity and sulphide concentrations, leading to decomposition and additional eutrophication. SO₄ pollution and concomitant sulphide production considerably reduced biomass production and colonization, but macrophytes were less vulnerable in fertilized conditions. The experiment shows that competition between species, vegetation succession and terrestrialization are not only influenced by nutrient availability, but also by toxicity, which strongly interacts with the level of eutrophication. This implies that previously neutralized toxicity effects in eutrophied fens may appear after nutrient reduction measures have been taken. Interspecific competition, vegetation succession and terrestrialization in fens depend on the interacting effects of SO₄ pollution, sulphide toxicity and nutrient availability.
Afficher plus [+] Moins [-]Effects of inorganic lead on Western fence lizards (Sceloporus occidentalis) Texte intégral
2009
Salice, Christopher J. | Suski, Jamie G. | Bazar, Matthew A. | Talent, Larry G.
Although anthropogenic pollutants are thought to threaten reptilian species, there are few toxicity studies on reptiles. We evaluated the toxicity of Pb as lead acetate to the Western fence lizard (Sceloporus occidentalis). The acute lethal dose and sub-acute (14-day) toxicity studies were used to narrow exposure concentrations for a sub-chronic (60-day) study. In the sub-chronic study, adult and juvenile male lizards were dosed via gavage with 0, 1, 10 and 20 mg Pb/kg-bw/day. Mortality was limited and occurred only at the highest dose (20 mg Pb/kg-bw/d). There were statistically significant sub-lethal effects of 10 and 20 mg Pb/kg-bw/d on body weight, cricket consumption, organ weight, hematological parameters and post-dose behaviors. Of these, Pb-induced changes in body weight are most useful for ecological risk assessment because it is linked to fitness in wild lizard populations. The Western fence lizard is a useful model for reptilian toxicity studies. The Western fence lizard, Sceloporus occidentalis, is sensitive to Pb and is a useful laboratory model for ecotoxicological testing of reptiles.
Afficher plus [+] Moins [-]Evaluation of approaches to calculate critical metal loads for forest ecosystems Texte intégral
2009
Vries, W de | Groenenberg, J.E.
This paper evaluates approaches to calculate acceptable loads for metal deposition to forest ecosystems, distinguishing between critical loads, stand-still loads and target loads. We also evaluated the influence of including the biochemical metal cycle on the calculated loads. Differences are illustrated by examples of Cd, Cu, Pb and Zn for a deciduous forest on five major soil types in the Netherlands. Stand-still loads are generally lower than critical loads, which in turn are lower than the target loads indicating that present levels are below critical levels. Uncertainties in the calculated critical loads are mainly determined by the uncertainty in the critical limits and the chemical speciation model. Including the metal cycle has a small effect on the calculated critical loads. Results are discussed in view of the applicability of the critical load concept for metals in future protocols on the reduction in metal emissions. Critical load methods for metals can be used to assess future risks due to metal inputs.
Afficher plus [+] Moins [-]Progestagens for human use, exposure and hazard assessment for the aquatic environment Texte intégral
2009
Besse, Jean-Philippe | Garric, Jeanne
Little information is available on the environmental occurrence and ecotoxicological effects of pharmaceutical gestagens released in the aquatic environment. Since eighteen different gestagens were found to be used in France, preliminary exposure and hazard assessment were done. Predicted environmental concentrations (PECs) suggest that if parent gestagens are expected to be found in the ng l−1 range, some active metabolites could be present at higher concentrations, although limited data on metabolism and environmental fate limit the relevance of PECs. The biological effects are not expected to be restricted to progestagenic activity. Both anti-androgenic activity (mainly for cyproterone acetate, chlormadinone acetate and their metabolites) and estrogenic activity (mainly for reduced metabolites of levonorgestrel and norethisterone) should also occur. All these molecules are likely to have a cumulative effect among themselves or with other xenoestrogens. Studies on occurrence, toxicity and degradation time are therefore needed for several of these compounds. Gestagens exposure and hazard assessment for the aquatic environment.
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