Уточнить поиск
Результаты 281-290 из 753
Sterilization affects soil organic matter chemistry and bioaccumulation of spiked p,p′-DDE and anthracene by earthworms Полный текст
2010
Kelsey, Jason W. | Slizovskiy, Ilya B. | Peters, Richard D. | Melnick, Adam M.
Laboratory experiments were conducted to assess the effects of soil sterilization on the bioavailability of spiked p,p'-DDE and anthracene to the earthworms Eisenia fetida and Lumbricus terrestris. Physical and chemical changes to soil organic matter (SOM) induced by sterilization were also studied. Uptake of both compounds added after soil was autoclaved or gamma irradiated increased for E. fetida. Sterilization had no effect on bioaccumulation of p,p′-DDE by L. terrestris, and anthracene uptake increased only in gamma-irradiated soils. Analyses by FT-IR and DSC indicate sterilization alters SOM chemistry and may reduce pollutant sorption. Chemical changes to SOM were tentatively linked to changes in bioaccumulation, although the effects were compound and species specific. Artifacts produced by sterilization could lead to inaccurate risk assessments of contaminated sites if assumptions derived from studies carried out in sterilized soil are used. Ultimately, knowledge of SOM chemistry could aid predictions of bioaccumulation of organic pollutants.
Показать больше [+] Меньше [-]Pd-nanoparticles cause increased toxicity to kiwifruit pollen compared to soluble Pd(II) Полный текст
2010
Speranza, Anna | Leopold, Kerstin | Maier, Marina | Taddei, Anna Rita | Scoccianti, Valeria
In the present study, endpoints including in vitro pollen performance (i.e., germination and tube growth) and lethality were used as assessments of nanotoxicity. Pollen was treated with 5–10 nm-sized Pd particles, similar to those released into the environment by catalytic car exhaust converters. Results showed Pd-nanoparticles altered kiwifruit pollen morphology and entered the grains more rapidly and to a greater extent than soluble Pd(II). At particulate Pd concentrations well below those of soluble Pd(II), pollen grains experienced rapid losses in endogenous calcium and pollen plasma membrane damage was induced. This resulted in severe inhibition and subsequent cessation of pollen tube emergence and elongation at particulate Pd concentrations as low as 0.4 mg L−1. Particulate Pd emissions related to automobile traffic have been increasing and are accumulating in the environment. This could seriously jeopardize in vivo pollen function, with impacts at an ecosystem level. Nanoparticulate Pd – which resembles emissions from automobile catalysts – affects pollen to a higher extent than soluble Pd.
Показать больше [+] Меньше [-]Seasonal acclimation of the moss Polytrichum juniperinum Hedw. to natural and enhanced ultraviolet radiation Полный текст
2010
Lappalainen, Niina M. | Huttunen, Satu | Suokanerva, Hanne | Lakkala, Kaisa
Short- and long-term changes in the methanol-extractable UV-absorbing compounds and biomass of the pioneer moss Polytrichum juniperinum in response to natural and enhanced UV radiation were studied. Under natural conditions, the compounds were found to fluctuate seasonally. In summer these compounds correlated negatively with irradiation. The concentration was low in July after a period of simultaneous heat, drought and high irradiation. Transient positive correlation between daily concentration and UV was seen in June. The concentration increased towards autumn and was relatively high under snow. Two enhanced UV experiments were performed. Seasonality in the compounds was again observed, with negative correlations with irradiation. During the first weeks, a transient inhibition of compound production was observed after the daily UV-B treatment. After six years of modulated UV-treatment in situ, photosynthesising biomass decreased under UV-B and increased under UV-A. A larger variation in the UV-absorbing compounds was observed under UV-B treatment. Juniper polytrichum moss is affected by drought, overwintering conditions and UV.
Показать больше [+] Меньше [-]Mobility of arsenic, cadmium and zinc in a multi-element contaminated soil profile assessed by in-situ soil pore water sampling, column leaching and sequential extraction Полный текст
2010
Beesley, Luke | Moreno-Jiménez, Eduardo | Clemente, Rafael | Lepp, Nicholas | Dickinson, Nicholas
Three methods for predicting element mobility in soils have been applied to an iron-rich soil, contaminated with arsenic, cadmium and zinc. Soils were collected from 0 to 30 cm, 30 to 70 cm and 70 to 100 cm depths in the field and soil pore water was collected at different depths from an adjacent 100 cm deep trench. Sequential extraction and a column leaching test in the laboratory were compared to element concentrations in pore water sampled directly from the field. Arsenic showed low extractability, low leachability and occurred at low concentrations in pore water samples. Cadmium and zinc were more labile and present in higher concentrations in pore water, increasing with soil depth. Pore water sampling gave the best indication of short term element mobility when field conditions were taken into account, but further extraction and leaching procedures produced a fuller picture of element dynamics, revealing highly labile Cd deep in the soil profile. Mobility of arsenic, cadmium and zinc in a polluted soil can be realistically interpreted by in-situ soil pore water sampling.
Показать больше [+] Меньше [-]Dissipation and metabolism of 14C-spiroxamine in soil under laboratory condition Полный текст
2010
Sukul, Premasis | Zühlke, Sebastian | Lamshöft, Marc | Rosales-Conrado, Noelia | Spiteller, M (Michael)
Spiroxamine [SPX] belongs to a spiroketalamine group of substances. The biodegradation of [1,3-dioxolane-4-14C]-SPX has been examined in 2 soils of different physicochemical properties. The total recovery of radioactivity from soils was 98.6-103.5% of that applied. The total amount of extractable radioactivity declined with a simultaneous increase in non-extractable radioactivity. Volatile organics were detected at lower levels; however, mineralization played a marked effect on the route of SPX dissipation. The half-life ranges between 37 and 44 d. SPX does not undergo any enantioselective degradation. 4 metabolites: despropyl-SPX, desethyl-SPX, SPX N-oxide and SPX acid were identified, applying mass spectrometric technique. Sorption-desorption data fitted well with a Freundlich model in log form (r2, 0.99). KDsorp ranged between 44 and 230, suggesting SPX ought to be considered as a substance with low leaching potential [groundwater ubiquity score (GUS), <1.8]. Furthermore, an overall low desorption of 1–11% indicates firm retention of SPX by the soils.
Показать больше [+] Меньше [-]Hydrological regime and salinity alter the bioavailability of Cu and Zn in wetlands Полный текст
2010
Speelmans, M. | Lock, K. | Vanthuyne, D.R.J. | Hendrickx, F. | Du Laing, G. | Tack, F.M.G. | Janssen, C.R.
In the context of the European Water Framework Directive, controlled flooding of lowlands is considered as a potential water management strategy to minimise the risk of flooding of inhabited areas. However, due to historical pollution and overbank sedimentation, metal levels are elevated in most wetlands, which can cause adverse effects on the ecosystem's dynamics. Additionally, salinity affects the bioavailability of metals present or imported into these systems. The effect of different flooding regimes and salinity exposure scenarios (fresh- and brackish water conditions) on Cu and Zn accumulation in the oligochaete Tubifex tubifex (Müller, 1774) was examined. Metal mobility was closely linked to redox potential, which is directly related to the prevalent hydrological regime. Flooded, and thus more reduced, conditions minimized the availability of metals, while oxidation of the substrates during a drier period was associated with a rapid increase of metal availability and accumulation in the oligochaetes.
Показать больше [+] Меньше [-]Distribution of polybrominated diphenyl ethers (PBDEs) and polybrominated dibenzo-p-dioxins and dibenzofurans (PBDD/Fs) in municipal solid waste incinerators Полный текст
2010
Wang, Lin-Chi | Hsi, Hsing-Cheng | Wang, Yafen | Lin, Sheng-Lun | Chang-Chien, Guo-Ping
The stack flue gases and the ashes in different units of two municipal solid waste incinerators (MSWIs) are sampled to investigate the characteristics of polybrominated diphenyl ethers (PBDEs), polybrominated dibenzo-p-dioxins and dibenzofurans (PBDD/Fs), and polychlorinated dibenzo-p-dioxins and dibenzofurans (PCDD/Fs). Bottom ashes (BA) exhibited much higher PBDD/F (8.11-52.2 pg TEQ/g) and PBDE contents (20.4-186 ng/g) than those of fly ashes (0.0932-2.02 pg TEQ/g and 0.332–25.5 ng/g), revealing that the PBDD/Fs and PBDEs in the feeding waste may not be completely destroyed. The PBDE concentrations/contents in the stack flue gases (26.1-109 ng/Nm3) and in the BA (20.4-186 ng/g) of the MSWIs could reach three orders higher than those in the atmosphere and reference soils. PBDE contributions to the environment from the stack flue gases or the reutilization of BA of MSWIs should not be ignored from the developing PBDE inventory.
Показать больше [+] Меньше [-]How are macroinvertebrates of slow flowing lotic systems directly affected by suspended and deposited sediments Полный текст
2010
Kefford, Ben J. | Zalizniak, Liliana | Dunlop, Jason E. | Nugegoda, Dayanthi | Choy, S. C. (Satish C)
How are macroinvertebrates of slow flowing lotic systems directly affected by suspended and deposited sediments Полный текст
2010
Kefford, Ben J. | Zalizniak, Liliana | Dunlop, Jason E. | Nugegoda, Dayanthi | Choy, S. C. (Satish C)
The effects of suspended and deposited sediments on the macroinvertebrates are well documented in upland streams but not in slower flowing lowland rivers. Using species found in lowland lotic environments, we experimentally evaluate mechanisms for sediments to affect macroinvertebrates, and in one experiment whether salinity alters the effect of suspended sediments. Suspended kaolin clay reduced feeding of Ischnura heterosticta (Odonata: Coenagrionidae) at high turbidity (1000–1500 NTU) but had no effects on feeding of Hemianax papuensis (Odonata: Aeshnidae) and Micronecta australiensis (Hemiptera: Corixidae). In freshwater (0.1 mS/cm), survival of Ischnura aurora was poor in clear water, but improved with suspended kaolin. Growth and feeding of I. aurora were unaffected by suspended sediments and salinity. Burial (1–5 mm) of eggs with kaolin or sand reduced hatching in Physa acuta (Gastropoda: Physidae), Gyraulus tasmanica (Gastropoda: Planorbidae) and Chironomus cloacalis (Diptera: Chironomidae). Settling sediments may pose greater risk to lowland lotic invertebrates than suspended sediments. Sediment deposition may be more directly detrimental to macroinvertebrates of lowland rivers than suspended sediments.
Показать больше [+] Меньше [-]How are macroinvertebrates of slow flowing lotic systems directly affected by suspended and deposited sediments? Полный текст
2009
Kefford, BJ | Zalizniak, L | Dunlop, JE | Nugegoda, D | Choy, SC
Anchoring novel molecular biomarker responses to traditional responses in fish exposed to environmental contamination Полный текст
2010
Nogueira, Patrícia | Pacheco, Mario | Pereira, M Lourdes | Mendo, Sónia | Rotchell, Jeanette M.
Anchoring novel molecular biomarker responses to traditional responses in fish exposed to environmental contamination Полный текст
2010
Nogueira, Patrícia | Pacheco, Mario | Pereira, M Lourdes | Mendo, Sónia | Rotchell, Jeanette M.
The responses of Dicentrarchus labrax and Liza aurata to aquatic pollution were assessed in a contaminated coastal lagoon, using both traditional and novel biomarkers combined. DNA damage, assessed by comet assay, was higher in both fish species from the contaminated sites, whereas levels of cytochrome P450 1A1 gene expression were not significantly altered. The liver histopathological analysis also revealed significant lesions in fish from contaminated sites. Alterations in ras and xpf genes were analysed and additional pollutant-responsive genes were identified. While no alterations were found in ras gene, a downregulation of xpf gene was observed in D. labrax from a contaminated site. Suppression subtractive hybridization applied to D. labrax collected at a contaminated site, revealed altered expression in genes involved in energy metabolism, immune system activity and antioxidant response. The approach and results reported herein demonstrate the utility of anchoring traditional biomarker responses alongside novel biomarker responses.
Показать больше [+] Меньше [-]Anchoring novel molecular biomarker responses to traditional responses in fish exposed to environmental contamination Полный текст
1000
Nogueira, Patrícia | Pacheco, Mário | Pereira, M. Lourdes | Mendo, Sónia | Rotchell, Jeanette M.
The responses of Dicentrarchus labrax and Liza aurata to aquatic pollution were assessed in a contaminated coastal lagoon, using both traditional and novel biomarkers combined. DNA damage, assessed by comet assay, was higher in both fish species from the contaminated sites, whereas levels of cytochrome P450 1A1 gene expression were not significantly altered. The liver histopathological analysis also revealed significant lesions in fish from contaminated sites. Alterations in ras and xpf genes were analysed and additional pollutant-responsive genes were identified. While no alterations were found in ras gene, a downregulation of xpf gene was observed in D. labrax from a contaminated site. Suppression subtractive hybridization applied to D. labrax collected at a contaminated site, revealed altered expression in genes involved in energy metabolism, immune system activity and antioxidant response. The approach and results reported herein demonstrate the utility of anchoring traditional biomarker responses alongside novel biomarker responses.
Показать больше [+] Меньше [-]Blood biomarkers and contaminant levels in feathers and eggs to assess environmental hazards in heron nestlings from impacted sites in Ebro basin (NE Spain) Полный текст
2010
Barata, C. | Fabregat, M.C. | Cotín, J. | Huertas, D. | Solé, M. | Quirós, L. | Sanpera, C. | Jover, L. | Ruiz, X. | Grimalt, J.O. | Piña, B.
Blood biomarkers and contaminant levels in feathers and eggs to assess environmental hazards in heron nestlings from impacted sites in Ebro basin (NE Spain) Полный текст
2010
Barata, C. | Fabregat, M.C. | Cotín, J. | Huertas, D. | Solé, M. | Quirós, L. | Sanpera, C. | Jover, L. | Ruiz, X. | Grimalt, J.O. | Piña, B.
Blood biomarkers and levels of major pollutants in eggs and feathers were used to determine pollution effects in nestlings of the Purple Heron Ardea purpurea and the Little Egret Egretta garzetta, sampled on three Ebro River (NE Spain) areas: a reference site, a site affected by the effluents of a chlor-alkali industry and the river Delta. The two impacted heron populations showed mutually different pollutant and response patterns, suggesting different sources of contamination. In the population nesting near the chlor-alkali plant, elevated levels of hexachlorobenzene (HCB) and polychlorobiphenyls (PCBs) in eggs, and mercury in feathers in A. purpurea chicks were related with reduced blood antioxidant defenses and increased levels of micronuclei. In Ebro Delta, high levels of plasmatic lactate dehydrogenase in A. purpurea chicks and high frequency of micronuclei in blood of both species were tentatively associated with intensive agricultural activities taking place in the area. These results provide the first evidence of a biological response in heron chicks to the release of pollutants at a chlor-alkali plant. High levels of organochlorine and mercury levels in eggs and feathers were related with altered blood biomarkers of heron nesting chicks.
Показать больше [+] Меньше [-]Blood biomarkers and contaminant levels in feathers and eggs to assess environmental hazards in heron nestlings from impacted sites in Ebro basin (NE Spain) Полный текст
2010
Barata Martí, Carlos | Fabregat, M. C. | Cotín, J. | Huertas, David | Solé, Montserrat | Quirós, Laia | Sanpera, Carolina | Jover, Lluís | Ruiz, Xavier | Grimalt, Joan O. | Piña, Benjamín
7 pages, 2 figures, 3 tables | Blood biomarkers and levels of major pollutants in eggs and feathers were used to determine pollution effects in nestlings of the Purple Heron Ardea purpurea and the Little Egret Egretta garzetta, sampled on three Ebro River (NE Spain) areas: a reference site, a site affected by the effluents of a chlor-alkali industry and the river Delta. The two impacted heron populations showed mutually different pollutant and response patterns, suggesting different sources of contamination. In the population nesting near the chlor-alkali plant, elevated levels of hexachlorobenzene (HCB) and polychlorobiphenyls (PCBs) in eggs, and mercury in feathers in A. purpurea chicks were related with reduced blood antioxidant defenses and increased levels of micronuclei. In Ebro Delta, high levels of plasmatic lactate dehydrogenase in A. purpurea chicks and high frequency of micronuclei in blood of both species were tentatively associated with intensive agricultural activities taking place in the area. These results provide the first evidence of a biological response in heron chicks to the release of pollutants at a chlor-alkali plant. High levels of organochlorine and mercury levels in eggs and feathers were related with altered blood biomarkers of heron nesting chicks | This work has been supported by the Spanish Ministry for the Environment, the Catalan Water Agency (ACA) of the Generalitat de Catalunya and GRACCIE and AQUATOXIGEN (CSD2007-00067, CGL2008-01898) from the Spanish Ministry of Science | Peer reviewed
Показать больше [+] Меньше [-]