خيارات البحث
النتائج 251 - 260 من 1,546
A contribution towards the risk assessment of soils from the São Domingos Mine (Portugal): Chemical, microbial and ecotoxicological indicators النص الكامل
2012
Alvarenga, Paula | Palma, Patricia | de Varennes, Amarilis | Cunha-Queda, Ana C.
This study is a contribution towards a risk assessment of the São Domingos Mine area (Portugal), integrating information from: soil physicochemical characteristics, pseudo-total and bioavailable trace elements (As, Cd, Cr, Cu, Ni, Pb and Zn), ecotoxicological evaluation, and microbial indicators. The bioassays using soil eluates (seed germination, luminescent inhibition of Vibrio fischeri and Daphnia magna immobilization) confirmed the soil toxicity categorization obtained with the bioassays using soil (plant growth tests, Eisenia fetida mortality and avoidance behaviour). However, the soil identified as the most toxic using bioassays, was different from the expected when considering the results from pseudo-total and effective bioavailable trace elements. Taking in consideration the observations, it is highly recommended to complement the results from environmental chemistry with results from bioassays, in order to provide a more complete and relevant information on the bioavailability of contaminants and to characterize the risk of contaminated soils.
اظهر المزيد [+] اقل [-]Soil invertebrates as bioindicators of urban soil quality النص الكامل
2012
Santorufo, Lucia | Van Gestel, Cornelis A.M. | Rocco, Annamaria | Maisto, Giulia
This study aimed at relating the abundance and diversity of invertebrate communities of urban soils to chemical and physical soil characteristics and to identify the taxa most sensitive or tolerant to soil stressors. The invertebrate community of five urban soils in Naples, Italy, was sampled. To assess soil quality invertebrate community indices (Shannon, Simpson, Menhinick and Pielou indices), Acarina/Collembola ratios, and the soil biological quality index (QBS) were calculated. The chemical and physical characteristics of the soils strongly differed. Abundance rather than taxa richness of invertebrates were more affected by soil characteristics. The community was more abundant and diverse in the soils with high organic matter and water content and low metal (Cu, Pb, Zn) concentrations. The taxa more resistant to the urban environment included Acarina, Enchytraeids, Collembola and Nematoda. Collembolans appeared particularly sensitive to changing soil properties. Among the investigated indices, QBS seems most appropriate for soil quality assessment.
اظهر المزيد [+] اقل [-]Insights into low fish mercury bioaccumulation in a mercury-contaminated reservoir, Guizhou, China النص الكامل
2012
Liu, Bian | Yan, Haiyu | Wang, Cuiping | Li, Qiuhua | Guédron, Stéphane | Spangenberg, Jorge E. | Feng, Xinbin | Dominik, Janusz
We examined Hg biogeochemistry in Baihua Reservoir, a system affected by industrial wastewater containing mercury (Hg). As expected, we found high levels of total Hg (THg, 664–7421 ng g⁻¹) and monomethylmercury (MMHg, 3–21 ng g⁻¹) in the surface sediments (0–10 cm). In the water column, both THg and MMHg showed strong vertical variations with higher concentrations in the anoxic layer (>4m) than in the oxic layer (0–4 m), which was most pronounced for the dissolved MMHg (p < 0.001). However, mercury levels in biota samples (mostly cyprinid fish) were one order of magnitude lower than common regulatory values (i.e. 0.3–0.5 mg kg⁻¹) for human consumption. We identified three main reasons to explain the low fish Hg bioaccumulation: disconnection of the aquatic food web from the high MMHg zone, simple food web structures, and biodilution effect at the base of the food chain in this eutrophic reservoir.
اظهر المزيد [+] اقل [-]Distribution and toxicity of current-use insecticides in sediment of a lake receiving waters from areas in transition to urbanization النص الكامل
2012
Wang, Ji-Zhong | Li, Hui-Zhen | Yau, Ching
Current-use insecticides including organophosphate (OPs) and synthetic pyrethroid (SPs) insecticides were analyzed in 35 sediment samples collected from Chaohu Lake in China, where a transition from a traditional agricultural to a modern urbanized society is ongoing. Total concentrations of five OPs and eight SPs ranged from 0.029 to 0.681 ng/g dry weight and 0.016–301 ng/g dry weight, respectively. Toxic unit analysis showed that 13% of the sediment samples likely produced over 50% of the mortality for benthic invertebrates. Analysis also showed that cypermethrin was the principal contributor to the toxicity. Spatial distribution evaluation implied that OPs were mainly from non-point sources associated with agricultural activities. Conversely, SPs may have been derived from runoff of inflowing rivers through urban regions, as their concentrations were well-correlated with concentrations of other urban-oriented contaminants.
اظهر المزيد [+] اقل [-]Estimating pesticide sampling rates by the polar organic chemical integrative sampler (POCIS) in the presence of natural organic matter and varying hydrodynamic conditions النص الكامل
2012
Charlestra, Lucner | Amirbahman, Aria | Courtemanch, David L. | Alvarez, David A. | Patterson, Howard
The polar organic chemical integrative sampler (POCIS) was calibrated to monitor pesticides in water under controlled laboratory conditions. The effect of natural organic matter (NOM) on the sampling rates (Rₛ) was evaluated in microcosms containing <0.1–5 mg L⁻¹ of total organic carbon (TOC). The effect of hydrodynamics was studied by comparing Rₛ values measured in stirred (SBE) and quiescent (QBE) batch experiments and a flow-through system (FTS). The level of NOM in the water used in these experiments had no effect on the magnitude of the pesticide sampling rates (p > 0.05). However, flow velocity and turbulence significantly increased the sampling rates of the pesticides in the FTS and SBE compared to the QBE (p < 0.001). The calibration data generated can be used to derive pesticide concentrations in water from POCIS deployed in stagnant and turbulent environmental systems without correction for NOM.
اظهر المزيد [+] اقل [-]Associations between standardized school performance tests and mixtures of Pb, Zn, Cd, Ni, Mn, Cu, Cr, Co, and V in community soils of New Orleans النص الكامل
2012
Zahran, Sammy | Mielke, Howard W. | Weiler, Stephan | Hempel, Lynn | Berry, Kenneth J. | Gonzales, Christopher R.
In New Orleans a strong inverse association was previously identified between community soil lead and 4th grade school performance. This study extends the association to zinc, cadmium, nickel, manganese, copper, chromium, cobalt, and vanadium in community soil and their comparative effects on 4th grade school performance. Adjusting for poverty, food security, racial composition, and teacher-student ratios, regression results show that soil metals variously reduce and compress student scores. Soil metals account for 22%–24% while food insecurity accounts for 29%–37% of variation in school performance. The impact on grade point averages were Ni > Co > Mn > Cu ∼Cr ∼ Cd > Zn > Pb, but metals are mixtures in soils. The quantities of soil metal mixtures vary widely across the city with the largest totals in the inner city and smallest totals in the outer city. School grade point averages are lowest where the soil metal mixtures and food insecurity are highest.
اظهر المزيد [+] اقل [-]Contrasting levels of heavy metals in the feathers of urban pigeons from close habitats suggest limited movements at a restricted scale النص الكامل
2012
Frantz, Adrien | Pottier, Marie-Anne | Karimi, Battle | Corbel, Hélène | Aubry, Emmanuel | Haussy, Claudy | Gasparini, Julien | Castrec-Rouelle, Maryse
Contrasting levels of heavy metals in the feathers of urban pigeons from close habitats suggest limited movements at a restricted scale النص الكامل
2012
Frantz, Adrien | Pottier, Marie-Anne | Karimi, Battle | Corbel, Hélène | Aubry, Emmanuel | Haussy, Claudy | Gasparini, Julien | Castrec-Rouelle, Maryse
Despite restrictions in emissions, heavy metals may remain a major environmental issue due to their numerous sources and their persistence. Here, we assessed current levels of 4 metals (Copper, Cadmium, Lead, Zinc) in the feathers of 91 feral pigeons (Columba livia) from 7 sites in the urbanized region of Paris. Elements were detected in all pigeons, indicating that metals persist in urbanized areas. The ratio between metal concentrations in the feathers vs. in the environment calculated using data from other studies was 2–90 times higher for cadmium than for other metals, underlying its ecological importance. Concentrations in the feathers depended on locality, suggesting that pigeons remain in local habitats at this restricted scale, as expected from previous observations. Overall, our study suggests that urban feral pigeons may represent a good model system for metal biomonitoring.
اظهر المزيد [+] اقل [-]Contrasting levels of heavy metals in the feathers of urban pigeons from close habitats suggest limited movements at a restricted scale النص الكامل
2012
Frantz, Adrien | Pottier, Marie-Anne | Karimi, Battle | Corbel, Hélène | Aubry, Emmanuel | Haussy, Claudy | Gasparini, Julien | Castrec-Rouelle, Maryse | Biogéochimie et écologie des milieux continentaux (Bioemco) ; École normale supérieure - Paris (ENS-PSL) ; Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Institut de Recherche pour le Développement (IRD)-Institut National de la Recherche Agronomique (INRA)-Université Pierre et Marie Curie - Paris 6 (UPMC)-AgroParisTech-Centre National de la Recherche Scientifique (CNRS) | Centre National de la Recherche Scientifique | Universite Pierre Marie Curie
International audience | Despite restrictions in emissions, heavy metals may remain a major environmental issue due to their numerous sources and their persistence. Here, we assessed current levels of 4 metals (Copper, Cadmium, Lead, Zinc) in the feathers of 91 feral pigeons (Columba livia) from 7 sites in the urbanized region of Paris. Elements were detected in all pigeons, indicating that metals persist in urbanized areas. The ratio between metal concentrations in the feathers vs. in the environment calculated using data from other studies was 2-90 times higher for cadmium than for other metals, underlying its ecological importance. Concentrations in the feathers depended on locality, suggesting that pigeons remain in local habitats at this restricted scale, as expected from previous observations. Overall, our study suggests that urban feral pigeons may represent a good model system for metal biomonitoring. (c) 2012 Elsevier Ltd. All rights reserved.
اظهر المزيد [+] اقل [-]Contrasting levels of heavy metals in the feathers of urban pigeons from close habitats suggest limited movements at a restricted scale النص الكامل
2012
Frantz, Adrien | Pottier, Marie-Anne | Karimi, Battle | Corbel, Hélène | Aubry, Emmanuel | Haussy, Claudy | Gasparini, Julien | Castrec-Rouelle, Maryse | Biogéochimie et écologie des milieux continentaux (Bioemco) ; École normale supérieure - Paris (ENS-PSL) ; Université Paris Sciences et Lettres (PSL)-Université Paris Sciences et Lettres (PSL)-Institut de Recherche pour le Développement (IRD)-Institut National de la Recherche Agronomique (INRA)-Université Pierre et Marie Curie - Paris 6 (UPMC)-AgroParisTech-Centre National de la Recherche Scientifique (CNRS) | Centre National de la Recherche Scientifique | Universite Pierre Marie Curie
International audience | Despite restrictions in emissions, heavy metals may remain a major environmental issue due to their numerous sources and their persistence. Here, we assessed current levels of 4 metals (Copper, Cadmium, Lead, Zinc) in the feathers of 91 feral pigeons (Columba livia) from 7 sites in the urbanized region of Paris. Elements were detected in all pigeons, indicating that metals persist in urbanized areas. The ratio between metal concentrations in the feathers vs. in the environment calculated using data from other studies was 2-90 times higher for cadmium than for other metals, underlying its ecological importance. Concentrations in the feathers depended on locality, suggesting that pigeons remain in local habitats at this restricted scale, as expected from previous observations. Overall, our study suggests that urban feral pigeons may represent a good model system for metal biomonitoring. (c) 2012 Elsevier Ltd. All rights reserved.
اظهر المزيد [+] اقل [-]Improved reproductive success in otters (Lutra lutra), grey seals (Halichoerus grypus) and sea eagles (Haliaeetus albicilla) from Sweden in relation to concentrations of organochlorine contaminants النص الكامل
2012
Roos, Anna M. | Bäcklin, Britt-Marie V.M. | Helander, Björn O. | Rigét, Frank F. | Eriksson, Ulla C.
We studied indices of reproductive outcome in three aquatic species in relation to organochlorine concentrations during four decades. In female otters, the frequency of signs of reproduction increased after 1990. In grey seals, pregnancy rate increased 1990–2010 and uterine obstructions ceased after 1993. The frequency of uterine tumours was highest 1980–2000. The number of sea eagle nestlings per checked nest increased 1985–2000, while the frequency of desiccated eggs decreased. Organochlorine concentrations decreased at annual rates between 3.5 and 10.2%. The estimated mean concentration (mg/kg lw) for total-PCB decreased from 70 to 8 (otters), from 110 to 15 (seals) and from 955 to 275 (eagles). The corresponding concentrations for ΣDDT decreased from 3.4 to 0.2 (otters), from 192 to 2.8 (seals) and from 865 to 65 (eagles). This study adds evidence to support the hypothesis that PCBs and DDTs have had strong negative effects on the reproduction and population levels of these species.
اظهر المزيد [+] اقل [-]One year intensive PM₂.₅ bound polycyclic aromatic hydrocarbons monitoring in the area of Tuscany, Italy. Concentrations, source understanding and implications النص الكامل
2012
Martellini, Tania | Giannoni, Martina | Lepri, Luciano | Katsoyiannis, Athanasios | Cincinelli, Alessandra
Polycyclic aromatic hydrocarbons (PAHs) associated to PM₂.₅ particles were monitored at three sites in the region of Tuscany, Italy, during the period March 2009–March 2010. PAH concentrations ranged between 0.92 ng m⁻³ and 13 ng m⁻³. The spatial and seasonal differences observed at the three sites are discussed and attributed to specific PAH sources. Benzo[a]Pyrene average annual values were below the EU limit value of 1.0 ng m⁻³. The results of this study suggest that emissions from commuting and work related traffic play an important role for the city of Florence, whereas for the city of Livorno, the harbor activities seem to impact the PAH burden substantially, as well. The PAH cancer risk (expressed as the “BaPE index”) has shown a 6-fold decline compared to early 1990's concentrations and 2- to 3-fold decline compared to the late 1990's.
اظهر المزيد [+] اقل [-]Occurrence and persistence of organic emerging contaminants and priority pollutants in five sewage treatment plants of Spain: Two years pilot survey monitoring النص الكامل
2012
Bueno, M.J Martínez | Gomez, M.J. | Herrera, S. | Hernando, M.D. | Agüera, A. | Fernández-Alba, A.R.
This work summarized all results obtained during almost two-years of a monitoring programme carried out in five municipal sewage treatment plants (STPs) located in the north, centre and south-east of Spain. The study evaluated the occurrence and persistence of a group of 100 organic compounds belonging to several chemical groups (pharmaceuticals, personal care products, pesticides and metabolites). The average removal efficiencies of the STPs studied varied from 20% (erythromycin) to 99% (acetaminophen). In analysed samples, we identified a large number of compounds at mean range concentrations between 7–59,495 ng/L and 5–32,720 ng/L for influent and effluent samples, respectively. This study also identified 20 of the mostly detected and persistent compounds in wastewater effluent, of which hydrochlorothiazide, atenolol, gemfibrozil, galaxolide and three metabolites (fenofibric acid, 4-AAA and 4-FAA), presented the highest average contribution percentages, in relation to the total load of contaminants for the different STPs effluent studied.
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