Affiner votre recherche
Résultats 1-10 de 98
Caddisflies as biomonitors identifying thresholds of toxic metal bioavailability that affect the stream benthos Texte intégral
2012
Rainbow, P. S. | Hildrew, A. G. | Smith, Brian D. | Geatches, Tim | Luoma, Samuel N.
It has been proposed that bioaccumulated concentrations of toxic metals in tolerant biomonitors be used as indicators of metal bioavailability that could be calibrated against the ecological response to metals of sensitive biotic assemblages. Our hypothesis was that metal concentrations in caddisfly larvae Hydropsyche siltalai and Plectrocnemia conspersa, as tolerant biomonitors, indicate metal bioavailability in contaminated streams, and can be calibrated against metal-specific ecological responses of mayflies. Bioaccumulated concentrations of Cu, As, Zn and Pb in H. siltalai from SW English streams were related to the mayfly assemblage. Mayflies were always sparse where bioavailabilities were high and were abundant and diverse where bioavailabilities of all metals were low, a pattern particularly evident when the combined abundance of heptageniid and ephemerellid mayflies was the response variable. The results offer promise that bioaccumulated concentrations of metals in tolerant biomonitors can be used to diagnose ecological impacts on stream benthos from metal stressors.
Afficher plus [+] Moins [-]Imaging of metal bioaccumulation in Hay-scented fern (Dennstaedtia punctilobula) rhizomes growing on contaminated soils by laser ablation ICP-MS Texte intégral
2012
Koelmel, Jeremy | Amarasiriwardena, Dulasiri
Understanding Pb removal from the translocation stream is vital to engineering Pb hyperaccumulation in above ground organs, which would enhance the economic feasibility of Pb phytoextraction technologies. We investigated Cu, Pb, Sb and Zn distributions in Hay-scented fern (Dennstaedtia punctilobula) rhizomes on shooting range soils by laser ablation-inductively coupled plasma-mass spectrometry (LA-ICP-MS), analyzing digested rhizomes, stems, and fronds using ICP-MS. Nutrients Cu and Zn concentrated in fronds while toxic elements Pb and Sb did not, showing potential Pb and Sb sequestration in the rhizome. Frond and rhizome concentration of Pb was 0.17 ± 0.10% and 0.32 ± 0.21% of dry biomass, respectively. The ²⁰⁸Pb/¹³C and ¹²¹Sb/¹³C determined by LA-ICP-MS increased from inner sclerotic cortex to the epidermis, while Pb concentrated in the starchy cortex only in contaminated sites. These results suggest that concentration dependent bioaccumulation in the rhizome outer cortex removes Pb from the vascular transport stream.
Afficher plus [+] Moins [-]Quality of roof-harvested rainwater – Comparison of different roofing materials Texte intégral
2012
Lee, Ju Young | Bak, Gippeum | Han, Mooyoung
The objective of the study reported in this paper was to assess the quality of harvested rainwater on the basis of the roofing materials used and the presence of lichens/mosses on the roofing surface. Four pilot structures with different roofing materials (i.e., wooden shingle tiles, concrete tiles, clay tiles [Gi-Wa] and galvanized steel) were installed in a field. The galvanized steel was found to be the most suitable for rainwater harvesting applications, with their resulting physical and chemical water quality parameters meeting the Korean guidelines for drinking water quality (e.g., pH (5.8–8.5), TSS <500 mg/L, NO₃ ⁻ < 10 mg/L, SO₄ ²⁻ < 200 mg/L, Al < 0.2 mg/L, Cu < 1 mg/L, Fe < 0.3 mg/L, Pb < 0.05 mg/L, Zn < 1 mg/L, and E. coli (No detection)). In the galvanized steel case, the relatively high water quality was probably due to ultraviolet light and the high temperature effectively disinfecting the harvested rainwater. It was also found that the presence of lichens and mosses may adversely affect the physical, chemical and microbiological quality of rainwater.
Afficher plus [+] Moins [-]Impact of atmospheric deposition of As, Cd and Pb on their concentration in carrot and celeriac Texte intégral
2012
De Temmerman, Ludwig | Ruttens, Ann | Waegeneers, Nadia
Root crops, carrot and celeriac, were exposed to atmospheric deposition in a polluted versus reference area. An effect was observed on the As, Cd and Pb concentrations of the leaves and the storage organs. The concentrations in the whole storage organs correlated well with atmospheric deposition, which shows that they even could be used for biomonitoring. Nevertheless, leaves remain much more appropriate. The results revealed also a significant increase of the As and Cd concentration in the consumable part of the storage organs as a function of their atmospheric deposition. As such the experiments allowed deriving regression equations, useful for modeling the atmospheric impact of trace elements on the edible parts of root crops. For Pb, however, there was hardly any significant impact on the inner parts of the storage organs and as such the transfer of Pb in the food chain through root crops can be considered to be negligible.
Afficher plus [+] Moins [-]Formation and stability of Pb-, Zn- & Cu-PO₄ phases at low temperatures: Implications for heavy metal fixation in polar environments Texte intégral
2012
White, D. A. (Duanne A.) | Hafsteinsdóttir, Erla G. | Gore, Damian B. | Thorogood, Gordon | Stark, Scott C.
Low temperatures and frequent soil freeze–thaw in polar environments present challenges for the immobilisation of metals. To address these challenges we investigated the chemical forms of Pb, Zn and Cu in an Antarctic landfill, examined in vitro reaction kinetics of these metals and orthophosphate at 2 and 22 °C for up to 185 days, and subjected the products to freeze–thaw. Reaction products at both temperatures were similar, but the rate of production varied, with Cu-PO₄ phases forming faster, and the Zn- and Pb-PO₄ phases slower at 2 °C. All metal-orthophosphate phases produced were stable during a 2.5 h freeze–thaw cycle to −30 °C. Metal immobilisation using orthophosphate can be successful in polar regions, but treatments will need to consider differing mineral stabilities and reaction rates at low temperatures.
Afficher plus [+] Moins [-]Diffuse urban pollution increases metal tolerance of natural heterotrophic biofilms Texte intégral
2012
Fechner, Lise C. | Gourlay-Francé, Catherine | Bourgeault, Adeline | Tusseau-Vuillemin, Marie-Hélène
Diffuse urban pollution increases metal tolerance of natural heterotrophic biofilms Texte intégral
2012
Fechner, Lise C. | Gourlay-Francé, Catherine | Bourgeault, Adeline | Tusseau-Vuillemin, Marie-Hélène
This study is a first attempt to investigate the impact of urban contamination on metal tolerance of heterotrophic river biofilms using a short-term test based on β-glucosidase activity. Tolerance levels to Cu, Cd, Zn, Ni and Pb were evaluated for biofilms collected at three sites along an urban gradient in the Seine river (France). Metallic pollution increased along the river, but concentrations remained low compared to environmental quality standards. Biofilm metal tolerance increased downstream from the urban area. Multivariate analysis confirmed the correlation between tolerance and contamination and between multi-metallic and physico-chemical gradients. Therefore, tolerance levels have to be interpreted in relation to the whole chemical and physical characteristics and not solely metal exposure. We conclude that community tolerance is a sensitive biological response to urban pressure and that mixtures of contaminants at levels lower than quality standards might have a significant impact on periphytic communities.
Afficher plus [+] Moins [-]Diffuse urban pollution increases metal tolerance of natural heterotrophic biofilms Texte intégral
2012
Fechner, Lise | Gourlay-france, Catherine | Bourgeault, Adeline | Tusseau-vuillemin, Marie-helene
This study is a first attempt to investigate the impact of urban contamination on metal tolerance of heterotrophic river biofilms using a short-term test based on beta-glucosidase activity. Tolerance levels to Cu, Cd, Zn, Ni and Pb were evaluated for biofilms collected at three sites along an urban gradient in the Seine river (France). Metallic pollution increased along the river, but concentrations remained low compared to environmental quality standards. Biofilm metal tolerance increased downstream from the urban area. Multivariate analysis confirmed the correlation between tolerance and contamination and between multi-metallic and physico-chemical gradients. Therefore, tolerance levels have to be interpreted in relation to the whole chemical and physical characteristics and not solely metal exposure. We conclude that community tolerance is a sensitive biological response to urban pressure and that mixtures of contaminants at levels lower than quality standards might have a significant impact on periphytic communities. (C) 2011 Elsevier Ltd. All rights reserved.
Afficher plus [+] Moins [-]Diffuse urban pollution increases metal tolerance of natural heterotrophic biofilms Texte intégral
2012
Fechner, Lise, C. | Gourlay-Francé, Catherine | Bourgeault, Adeline | Tusseau-Vuillemin, Marie-Hélène | Hydrosystèmes et Bioprocédés (UR HBAN) ; Institut national de recherche en sciences et technologies pour l'environnement et l'agriculture (IRSTEA) | AgroParisTech | Laboratoire d'Océanographie Spatiale (LOS) ; Institut Français de Recherche pour l'Exploitation de la Mer (IFREMER)
[Departement_IRSTEA]Eaux [TR1_IRSTEA]BELCA | This study is a first attempt to investigate the impact of urban contamination on metal tolerance of heterotrophic river biofilms using a short-term test based on β-glucosidase activity. Tolerance levels to Cu, Cd, Zn, Ni and Pb were evaluated for biofilms collected at three sites along an urban gradient in the Seine river (France). Metallic pollution increased along the river, but concentrations remained low compared to environmental quality standards. Biofilm metal tolerance increased downstream from the urban area. Multivariate analysis confirmed the correlation between tolerance and contamination and between multi-metallic and physico-chemical gradients. Therefore, tolerance levels have to be interpreted in relation to the whole chemical and physical characteristics and not solely metal exposure. We conclude that community tolerance is a sensitive biological response to urban pressure and that mixtures of contaminants at levels lower than quality standards might have a significant impact on periphytic communities.
Afficher plus [+] Moins [-]Diffuse urban pollution increases metal tolerance of natural heterotrophic biofilms Texte intégral
2012
Fechner, L.C. | Gourlay-Francé, C. | Bourgeault, A. | Tusseau-Vuillemin, M.H. | AgroParisTech | Hydrosystèmes et Bioprocédés (UR HBAN) ; Institut national de recherche en sciences et technologies pour l'environnement et l'agriculture (IRSTEA) | Laboratoire d’Oéanographie Spatiale [Plouzané] (LOS) ; Institut Français de Recherche pour l'Exploitation de la Mer (IFREMER)
[Departement_IRSTEA]Eaux [TR1_IRSTEA]BELCA | This study is a first attempt to investigate the impact of urban contamination on metal tolerance of heterotrophic river biofilms using a short-term test based on β-glucosidase activity. Tolerance levels to Cu, Cd, Zn, Ni and Pb were evaluated for biofilms collected at three sites along an urban gradient in the Seine river (France). Metallic pollution increased along the river, but concentrations remained low compared to environmental quality standards. Biofilm metal tolerance increased downstream from the urban area. Multivariate analysis confirmed the correlation between tolerance and contamination and between multi-metallic and physico-chemical gradients. Therefore, tolerance levels have to be interpreted in relation to the whole chemical and physical characteristics and not solely metal exposure. We conclude that community tolerance is a sensitive biological response to urban pressure and that mixtures of contaminants at levels lower than quality standards might have a significant impact on periphytic communities.
Afficher plus [+] Moins [-]Bees, honey and pollen as sentinels for lead environmental contamination Texte intégral
2012
Lambert, Olivier | Piroux, Mélanie | Puyo, Sophie | Thorin, Chantal | Larhantec, Michaëlle | Delbac, Frédéric | Pouliquen, Hervé
Three beehive matrices, sampled in eighteen apiaries from West France, were analysed for the presence of lead (Pb). Samples were collected during four different periods in both 2008 and 2009. Honey was the matrix the least contaminated by Pb (min = 0.004 μg g⁻¹; max = 0.378 μg g⁻¹; mean = 0.047 μg g⁻¹; sd = 0.057). The contamination of bees (min = 0.001 μg g⁻¹; max = 1.869 μg g⁻¹; mean = 0.223 μg g⁻¹; sd = 0.217) and pollen (min = 0.004 μg g⁻¹; max = 0.798 μg g⁻¹; mean = 0.240 μg g⁻¹; sd = 0.200) showed similar levels and temporal variations but bees seemed to be more sensitive bringing out the peaks of Pb contamination. Apiaries in urban and hedgerow landscapes appeared more contaminated than apiaries in cultivated and island landscapes. Sampling period had a significant effect on Pb contamination with higher Pb concentrations determined in dry seasons.
Afficher plus [+] Moins [-]Blood Pb and δ-ALAD inhibition in cattle and sheep from a Pb-polluted mining area Texte intégral
2012
Rodríguez-Estival, Jaime | Barasona, José A. | Mateo, Rafael
The effects of Pb pollution on cattle and sheep raised in an ancient mining area were studied through the use of blood Pb (PbB) levels and δ-aminolevulinic acid dehydratase (δ-ALAD) activity. Lead levels in livestock blood from the mining area (n=110) were significantly elevated when compared to the controls (n=79). In 91.4% of cattle (n=58) and 13.5% of sheep (n=52) sampled in the mining area, PbB levels corresponded to subclinical exposure (6–35μg/dl). Two young cattle (<2 years) from the mining area (n=5) had PbB levels indicative of clinical poisoning (>35μg/dl). Elevated PbB was also accompanied by δ-ALAD activity inhibition in blood, which confirms that measurable effects of Pb poisoning were taking place. Observed PbB levels suggest that a potential risk to human consumers of beef from the Pb polluted areas may also exist, as has been shown previously for game meat from the same mining area.
Afficher plus [+] Moins [-]Lead phytotoxicity in soils and nutrient solutions is related to lead induced phosphorus deficiency Texte intégral
2012
Cheyns, Karlien | Peeters, Sofie | Delcourt, Dorien | Smolders, Erik
This study was set up to relate lead (Pb) bioavailability with its toxicity to plants in soils. Tomato and barley seedlings were grown in six different PbCl₂ spiked soils (pH: 4.7–7.4; eCEC: 4.2–41.7 cmolc/kg). Soils were leached and pH corrected after spiking to exclude confounding factors. Plant growth was halved at 1600–6500 mg Pb/kg soil for tomato and at 1900–8300 mg Pb/kg soil for barley. These soil Pb threshold were unrelated to soil pH, organic carbon, texture or eCEC and neither soil solution Pb nor Pb²⁺ ion activity adequately explained Pb toxicity among soils. Shoot phosphorus (P) concentrations significantly decreased with increasing soil Pb concentrations. Tomato grown in hydroponics at either varying P supply or at increasing Pb (equal initial P) illustrated that shoot P explained growth response in both scenarios. The results suggest that Pb toxicity is partially related to Pb induced P deficiency, likely due to lead phosphate precipitation.
Afficher plus [+] Moins [-]Bioacumulation and ultrastructural effects of Cd, Cu, Pb and Zn in the moss Scorpiurum circinatum (Brid.) Fleisch. & Loeske Texte intégral
2012
Basile, A. | Sorbo, S. | Pisani, T. | Paoli, L. | Munzi, S. | Loppi, S.
This paper tested if culturing the moss Scorpiurum circinatum (Brid.) Fleisch. & Loeske with metal solutions (Cd, Cu, Pb and Zn) for 30 days causes metal bioaccumulation and ultrastructural changes. The results showed that despite the high heavy metal concentrations in treatment solutions, treated samples did not show severe ultrastructural changes and cells were still alive and generally well preserved. Bioaccumulation highlighted that moss cells survived to heavy metal toxicity by immobilizing most toxic ions extracellularly, likely in binding sites of the cell wall, which is the main site of metal detoxification.
Afficher plus [+] Moins [-]