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Atmospheric nitrogen deposition: Revisiting the question of the importance of the organic component Texto completo
2011
Cornell, Sarah E.
The organic component of atmospheric reactive nitrogen plays a role in biogeochemical cycles, climate and ecosystems. Although its deposition has long been known to be quantitatively significant, it is not routinely assessed in deposition studies and monitoring programmes. Excluding this fraction, typically 25–35%, introduces significant uncertainty in the determination of nitrogen deposition, with implications for the critical loads approach. The last decade of rainwater studies substantially expands the worldwide dataset, giving enough global coverage for specific hypotheses to be considered about the distribution, composition, sources and effects of organic-nitrogen deposition. This data collation and meta-analysis highlights knowledge gaps, suggesting where data-gathering efforts and process studies should be focused. New analytical techniques allow long-standing conjectures about the nature and sources of organic N to be investigated, with tantalising indications of the interplay between natural and anthropogenic sources, and between the nitrogen and carbon cycles.
Mostrar más [+] Menos [-]Uranium bioaccumulation and biological disorders induced in zebrafish (Danio rerio) after a depleted uranium waterborne exposure Texto completo
2011
Barillet, Sabrina | Adam-Guillermin, Christelle | Palluel, Olivier | Porcher, Jean-Marc | Devaux, Alain
Because of its toxicity and its ubiquity within aquatic compartments, uranium (U) represents a significant hazard to aquatic species such as fish. In a previous study, we investigated some biological responses in zebrafish either exposed to depleted or to enriched U (i.e., to different radiological activities). However, results required further experiments to better understand biological responses. Moreover, we failed to clearly demonstrate a significant relationship between biological effects and U radiological activity. We therefore chose to herein examine U bioaccumulation and induced effects in zebrafish according to a chemical dose–response approach. Results showed that U is highly bioconcentrated in fish, according to a time- and concentration-dependent model. Additionally, hepatic antioxidant defenses, red blood cells DNA integrity and brain acetylcholinesterase activity were found to be significantly altered. Generally, the higher the U concentration, the sooner and/or the greater the effect, suggesting a close relationship between accumulation and effect.
Mostrar más [+] Menos [-]Nitrogen deposition and its ecological impact in China: An overview Texto completo
2011
Liu, Xuejun | Duan, Lei | Mo, Jiangming | Du, Enzai | Shen, Jianlin | Lu, Xiankai | Zhang, Ying | Zhou, Xiaobing | He, Chune | Zhang, Fusuo
Nitrogen (N) deposition is an important component in the global N cycle that has induced large impacts on the health and services of terrestrial and aquatic ecosystems worldwide. Anthropogenic reactive N (Nᵣ) emissions to the atmosphere have increased dramatically in China due to rapid agricultural, industrial and urban development. Therefore increasing N deposition in China and its ecological impacts are of great concern since the 1980s. This paper synthesizes the data from various published papers to assess the status of the anthropogenic Nᵣ emissions and N deposition as well as their impacts on different ecosystems, including empirical critical loads for different ecosystems. Research challenges and policy implications on atmospheric N pollution and deposition are also discussed. China urgently needs to establish national networks for N deposition monitoring and cross-site N addition experiments in grasslands, forests and aquatic ecosystems. Critical loads and modeling tools will be further used in Nᵣ regulation.
Mostrar más [+] Menos [-]Atmospheric phenanthrene pollution modulates carbon allocation in red clover (Trifolium pratense L.) Texto completo
2011
Desalme, Dorine | Binet, Philippe | Epron, Daniel | Bernard, Nadine | Gilbert, Daniel | Toussaint, Marie-Laure | Plain, Caroline | Chiapusio, Geneviève
Atmospheric phenanthrene pollution modulates carbon allocation in red clover (Trifolium pratense L.) Texto completo
2011
Desalme, Dorine | Binet, Philippe | Epron, Daniel | Bernard, Nadine | Gilbert, Daniel | Toussaint, Marie-Laure | Plain, Caroline | Chiapusio, Geneviève
The influence of atmospheric phenanthrene (PHE) exposure (160μgm⁻³) during one month on carbon allocation in clover was investigated by integrative (plant growth analysis) and instantaneous ¹³CO₂ pulse-labelling approaches. PHE exposure diminished plant growth parameters (relative growth rate and net assimilation rate) and disturbed photosynthesis (carbon assimilation rate and chlorophyll content), leading to a 25% decrease in clover biomass. The root-shoot ratio was significantly enhanced (from 0.32 to 0.44). Photosynthates were identically allocated to leaves while less allocated to stems and roots. PHE exposure had a significant overall effect on the ¹³C partitioning among clover organs as more carbon was retained in leaves at the expense of roots and stems. The findings indicate that PHE decreases root exudation or transfer to symbionts and in leaves, retains carbon in a non-structural form diverting photosynthates away from growth and respiration (emergence of an additional C loss process).
Mostrar más [+] Menos [-]Atmospheric phenanthrene pollution modulates carbon allocation in red clover (Trifolium pratense L.) Texto completo
2011
Desalme, Dorine | Binet, Philippe | Epron, Daniel, D. | Bernard, Nadine | Gilbert, Daniel | Toussaint, Marie-Laure | Plain, Caroline | Chiapusio, Geneviève | Laboratoire Chrono-environnement (UMR 6249) (LCE) ; Centre National de la Recherche Scientifique (CNRS)-Université de Franche-Comté (UFC) ; Université Bourgogne Franche-Comté [COMUE] (UBFC)-Université Bourgogne Franche-Comté [COMUE] (UBFC) | Ecologie et Ecophysiologie Forestières [devient SILVA en 2018] (EEF) ; Institut National de la Recherche Agronomique (INRA)-Université de Lorraine (UL) | Pays de Montbeliard Agglomeration (PMA)
International audience | The influence of atmospheric phenanthrene (PHE) exposure (160 mgm 3) during one month on carbon allocation in clover was investigated by integrative (plant growth analysis) and instantaneous 13CO2 pulse-labelling approaches. PHE exposure diminished plant growth parameters (relative growth rate and net assimilation rate) and disturbed photosynthesis (carbon assimilation rate and chlorophyll content), leading to a 25% decrease in clover biomass. The root-shoot ratio was significantly enhanced (from 0.32 to 0.44). Photosynthates were identically allocated to leaves while less allocated to stems and roots. PHE exposure had a significant overall effect on the 13C partitioning among clover organs as more carbon was retained in leaves at the expense of roots and stems. The findings indicate that PHE decreases root exudation or transfer to symbionts and in leaves, retains carbon in a non-structural form diverting photosynthates away from growth and respiration (emergence of an additional C loss process).
Mostrar más [+] Menos [-]Heavy metal pollution exerts reduction/adaptation in the diversity and enzyme expression profile of heterotrophic bacteria in Cochin estuary, India Texto completo
2011
Jose, Jiya | Giridhar, Rajesh | Anas, Abdulaziz | Loka Bharathi, P.A. | Nair, Shanta
Heavy metal pollution exerts reduction/adaptation in the diversity and enzyme expression profile of heterotrophic bacteria in Cochin estuary, India Texto completo
2011
Jose, Jiya | Giridhar, Rajesh | Anas, Abdulaziz | Loka Bharathi, P.A. | Nair, Shanta
Over the past three decades heavy metal pollution has increased substantially in Cochin estuary, south west coast of India. Here we studied the distribution, diversity and enzyme expression profile of culturable microbial population along a pollution gradient. The distribution of resistance against 5 mM concentration of Zn, Co, Ni and Cu was observed among 90–100% of bacterial isolates retrieved from highly polluted Eloor, whereas it was less than 40% in Vypin and Munambam. Similarly, there was a difference in the distribution and diversity of bacterial phyla with predominance of Proteobacteria in Eloor and Firmicutes in Munambam and Vypin. We observed that 75–100% of the organisms retrieved from Eloor had low levels of expression for hydrolytic enzyme. In conclusion, the heavy metal pollution in Cochin estuary brought in reduction/adaptation in the distribution, diversity and enzyme expression profile of bacteria, which may impart adverse impacts on ecosystem functioning.
Mostrar más [+] Menos [-]Heavy metal pollution exerts reduction/adaptation in the diversity and enzyme expression profile of heterotrophic bacteria in Cochin estuary, India
2011
Jose, J. | Giridhar, R. | Anas, A. | LokaBharathi, P.A. | Nair, S.
Over the past three decades heavy metal pollution has increased substantially in Cochin estuary, south west coast of India. The distribution, diversity and enzyme expression profile of culturable microbial population along a pollution gradient was studied. The distribution of resistance against 5 mM concentration of Zn, Co, Ni and Cu was observed among 90-100% of bacterial isolates retrieved from highly polluted Eloor, whereas it was less than 40% in Vypin and Munambam. Similarly, there was a difference in the distribution and diversity of bacterial phyla with predominance of Proteobacteria in Eloor and Firmicutes in Munambam and Vypin. We observed that 75-100% of the organisms retrieved from Eloor had low levels of expression for hydrolytic enzyme. In conclusion, the heavy metal pollution in Cochin estuary brought in reduction/adaptation in the distribution, diversity and enzyme expression profile of bacteria, which may impart adverse impacts on ecosystem functioning.
Mostrar más [+] Menos [-]Metal and metalloid contamination in roadside soil and wild rats around a Pb–Zn mine in Kabwe, Zambia Texto completo
2011
Nakayama, Shouta M.M. | Ikenaka, Yoshinori | Hamada, Kyohei | Muzandu, Kaampwe | Choongo, Kennedy | Teraoka, Hiroki | Mizuno, Naoharu | Ishizuka, Mayumi
Metal (Cr, Co, Cu, Zn, Cd, Pb, Ni) and metalloid (As) accumulation was studied in roadside soil and wild rat (Rattus sp.) samples from near a Pb–Zn mine (Kabwe, Zambia) and the capital city of Zambia (Lusaka). The concentrations of the seven metals and As in the soil samples and Pb in the rat tissue samples were quantified using atomic absorption spectroscopy. The concentrations of Pb, Zn, Cu, Cd, and As in Kabwe soil were much higher than benchmark values. Geographic Information System analysis indicated the source of metal pollution was mining and smelting activity. Interestingly, the area south of the mine was more highly contaminated even though the prevailing wind flow was westward. Wild rats from Kabwe had much higher tissue concentrations of Pb than those from Lusaka. Their body weight and renal Pb levels were negatively correlated, which suggests that mining activity might affect terrestrial animals in Kabwe.
Mostrar más [+] Menos [-]Thallium in the hydrosphere of south west England Texto completo
2011
Law, Sin | Turner, Andrew
Thallium is a highly toxic metal whose environmental concentrations, distributions and behaviour are not well understood. In the present study we measure the concentrations of Tl in filtered and unfiltered samples of rain, tap, river, estuarine and waste waters collected from south west England. Dissolved Tl was lowest (<20 ng L⁻¹) in tap water, rain water, treated sewage and landfill effluents, estuarine waters, and rivers draining catchments of sandstones and shales. Concentrations up to about 450 ng L⁻¹ were observed in rivers whose catchments are partly mineralized and where metal mining was historically important, and the highest concentration (∼1400 ng L⁻¹) was measured in water abstracted directly from an abandoned mine. Compared with other trace metals measured (e.g. As, Cd, Co, Cr, Cu, Ni, Pb, Zn), Tl has a low affinity for suspended particles and undergoes little removal by conventional (hydroxide precipitation) treatment of mine water.
Mostrar más [+] Menos [-]Direct and indirect effects of metal contamination on soil biota in a Zn–Pb post-mining and smelting area (S Poland) Texto completo
2011
Kapusta, Paweł | Szarek-Łukaszewska, Grażyna | Stefanowicz, Anna M.
Effects of metal contamination on soil biota activity were investigated at 43 sites in 5 different habitats (defined by substratum and vegetation type) in a post-mining area. Sites were characterised in terms of soil pH and texture, nutrient status, total and exchangeable metal concentrations, as well as plant species richness and cover, abundances of enchytraeids, nematodes and tardigrades, and microbial respiration and biomass. The concentrations of total trace metals were highest in soils developed on mining waste (metal-rich dolomite), but these habitats were more attractive than sandy sites for plants and soil biota because of their higher content of organic matter, clay and nutrients. Soil mesofauna and microbes were strongly dependent on natural habitat properties. Pollution (exchangeable Zn and Cd) negatively affected only enchytraeid density; due to a positive relationship between enchytraeids and microbes it indirectly reduced microbial activity.
Mostrar más [+] Menos [-]Nano-TiO₂ enhances the toxicity of copper in natural water to Daphnia magna Texto completo
2011
Fan, Wenhong | Cui, Minming | Liu, Hong | Wang, Chuan | Shi, Zhiwei | Tan, Cheng | Yang, Xiuping
The acute toxicity of engineered nanoparticles (NPs) in aquatic environments at high concentrations has been well-established. This study demonstrates that, at a concentration generally considered to be safe in the environment, nano-TiO₂ remarkably enhanced the toxicity of copper to Daphnia magna by increasing the copper bioaccumulation. Specifically, at 2mgL⁻¹ nano-TiO₂, the (LC₅₀) of Cu²⁺ concentration observed to kill half the population, decreased from 111μgL⁻¹ to 42μgL⁻¹. Correspondingly, the level of metallothionein decreased from 135μgg⁻¹ wet weight to 99μgg⁻¹ wet weight at a Cu²⁺ level of 100μgL⁻¹. The copper was found to be adsorbed onto the nano-TiO₂, and ingested and accumulated in the animals, thereby causing toxic injury. The nano-TiO₂ may compete for free copper ions with sulfhydryl groups, causing the inhibition of the detoxification by metallothioneins.
Mostrar más [+] Menos [-]Waste water treatment plants as sources of polyfluorinated compounds, polybrominated diphenyl ethers and musk fragrances to ambient air Texto completo
2011
Weinberg, Ingo | Dreyer, Annekatrin | Ebinghaus, Ralf
To investigate waste water treatment plants (WWTPs) as sources of polyfluorinated compounds (PFCs), polybrominated diphenyl ethers (PBDEs) and synthetic musk fragrances to the atmosphere, air samples were simultaneously taken at two WWTPs and two reference sites using high volume samplers. Contaminants were accumulated on glass fiber filters and PUF/XAD-2/PUF cartridges, extracted compound-dependent by MTBE/acetone, methanol, or hexane/acetone and detected by GC-MS or HPLC-MS/MS. Total (gas+particle phase) concentrations ranged from 97 to 1004pgm⁻³ (neutral PFCs), <MQL to 13pgm⁻³ (ionic PFCs), 5781 to 482,163pgm⁻³ (musk fragrances) and <1 to 27pgm⁻³ (PBDEs) and were usually higher at WWTPs than at corresponding reference sites, revealing that WWTPs can be regarded as sources of musk fragrances, PFCs and probably PBDEs to the atmosphere. Different concentrations at the two WWTPs indicated an influence of WWTP size or waste water origin on emitted contaminant amounts.
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