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New insights into the sorption mechanism of cadmium on red mud Full text
2011
Luo, Lei | Ma, Chenyan | Ma, Yibing | Zhang, Shuzhen | Lv, Jitao | Cui, Mingqi
Effectiveness and mechanism of cadmium (Cd) sorption on original, acidified and ball milling nano-particle red muds were investigated using batch sorption experiments, sequential extraction analysis and X-ray absorption near edge structure (XANES) spectroscopy. The maximum sorption capacity of Cd was 0.16, 0.19, and 0.21mol/kg for the original, acidified, and nano-particle red muds at pH 6.5, respectively. Both acidification and ball-milling treatments significantly enhanced Cd sorption and facilitated transformation of Cd into less extractable fractions. The Cd LIII-edge XANES analysis indicated the formation of inner-sphere complexes of Cd similar to XCdOH (X represents surface groups on red mud) on the red mud surfaces although outer-sphere complexes of Cd were the primary species. This work shed light on the potential application of red mud to remediate Cd-contaminated soils and illustrated the promising tool of XANES spectroscopy for speciation of multicomponent systems of environmental relevance.
Show more [+] Less [-]Potential mechanisms of phthalate ester embryotoxicity in the abalone Haliotis diversicolor supertexta Full text
2011
Zhou, Jin | Cai, Zhong-Hua | Xing, Ke-Zhi
The effects and associated toxicological mechanisms of five phthalate esters (PAEs) on abalone embryonic development were investigated by exposing the embryos to a range of PAEs concentrations (0.05, 0.2, 2 and 10μg/mL). The results showed that PAEs could significantly reduce embryo hatchability, increase developmental malformations, and suppress the metamorphosis of abalone larvae. The possible toxicological mechanisms of PAEs to abalone embryos included, affecting the Na⁺–K⁺-pump and Ca²⁺–Mg²⁺-pump activities, altering the peroxidase (POD) level and the malondialdehyde (MDA) production, damaging the extraembryonic membranes structure, as well as disrupting endocrine-related genes (gpx, cyp3a, and 17β-hsd 12) expression properties. Taken together, this work showed that PAEs adversely affected the embryonic ontogeny of abalone. The abilities of PAEs affecting the osmoregulation, inducing oxidative stress, damaging embryo envelope structure, and causing physiological homeostasis disorder, are likely to be a part of the common mechanisms responsible for their embryonic toxicity.
Show more [+] Less [-]New DDT inputs after 30 years of prohibition in Spain. A case study in agricultural soils from south-western Spain Full text
2011
Muñoz-Arnanz, Juan | Jiménez, Begoña
This study provides information on the current status of contamination by DDT in agricultural soils in south-western Spain. A recent use of technical DDT in at least 17% of the soils was found based on the values (<1) of the ratio [Formula: see text] . According to the ratio [Formula: see text] , a dicofol type contamination was detected in about 27% of the soils. A wide range of concentrations was observed (0.08–11.1 ng/g d.w.) regardless of the type of crop soil. Enantiomeric fractions (EFs), based on the chiral analysis of o,p′-DDT residues differed from the racemic value (0.500) in most soils but they were not correlated with the study variables [DDTs], SOM, [Formula: see text] and [Formula: see text] . Given the health risks posed by DDT, our findings support how the environmental control of legacy pollutants such as DDT cannot be neglected.
Show more [+] Less [-]Contrasting effects of black carbon amendments on PAH bioaccumulation by Chironomus plumosus larvae in two distinct sediments: Role of water absorption and particle ingestion Full text
2011
Wang, Fan | Bu, Qingwei | Xia, Xinghui | Shen, Mohai
Two sediment matrices with different characteristics were amended with chars from different sources for bioaccumulation assay with filter-feeding Chironomus plumosus larvae. Chars greatly decreased porewater concentrations of PAHs (Cᵢw) measured using polyethylene devices in sediments. In organic rich sediment matrix-based systems where suspended char particles were absent, PAH concentrations in larvae (CᵢB) were significantly correlated with Cᵢw, and there was no difference in water-based bioaccumulation factors (BAFs) between different treatments, suggesting that water absorption was the main contaminant uptake route for larvae. In organic poor sediment matrix-based systems where suspended char particles were present, poor Pearson correlation between CᵢB and Cᵢw was found, but there was a significant linear increase of BAF values with char contents, which indicated that ingestion of suspended char particles could also be important for PAH bioaccumulation. Therefore, we need to rethink of the effectiveness and risks for the application of black carbon to sediment/soil remediation.
Show more [+] Less [-]Changes in the chemistry of acidified Adirondack streams from the early 1980s to 2008 Full text
2011
Lawrence, G.B. | Simonin, H.A. | Baldigo, B.P. | Roy, K.M. | Capone, S.B.
Lakes in the Adirondack region of New York have partially recovered in response to declining deposition, but information on stream recovery is limited. Here we report results of Adirondack stream monitoring from the early 1980s to 2008. Despite a 50% reduction in atmospheric deposition of sulfur, overall increases in pH of only 0.28 and ANC of 13 μeq L⁻¹ were observed in 12 streams over 23 years, although greater changes did occur in streams with lower initial ANC, as expected. In the North Tributary of Buck Creek with high dissolved organic carbon (DOC) concentrations, SO₄ ²⁻ concentrations decreased from 1999 to 2008 at a rate of 2.0 μmol L⁻¹ y⁻¹, whereas in the neighboring South Tributary with low DOC concentrations, the decrease was only 0.73 μmol L⁻¹ y⁻¹. Ca²⁺ leaching decreased in the North Tributary due to the SO₄ ²⁻ decrease, but this was partially offset by an increase in Ca²⁺ leaching from increased DOC concentrations.
Show more [+] Less [-]Responses of a soil bacterium, Pseudomonas chlororaphis O6 to commercial metal oxide nanoparticles compared with responses to metal ions Full text
2011
Dimkpa, Christian O. | Calder, Alyssa | Britt, David W. | McLean, Joan E. | Anderson, Anne J.
The toxicity of commercially-available CuO and ZnO nanoparticles (NPs) to pathogenic bacteria was compared for a beneficial rhizosphere isolate, Pseudomonas chlororaphis O6. The NPs aggregated, released ions to different extents under the conditions used for bacterial exposure, and associated with bacterial cell surface. Bacterial surface charge was neutralized by NPs, dependent on pH. The CuO NPs were more toxic than the ZnO NPs. The negative surface charge on colloids of extracellular polymeric substances (EPS) was reduced by Cu ions but not by CuO NPs; the EPS protected cells from CuO NPs-toxicity. CuO NPs-toxicity was eliminated by a Cu ion chelator, suggesting that ion release was involved. Neither NPs released alkaline phosphatase from the cells’ periplasm, indicating minimal outer membrane damage. Accumulation of intracellular reactive oxygen species was correlated with CuO NPs lethality. Environmental deposition of NPs could create niches for ion release, with impacts on susceptible soil microbes.
Show more [+] Less [-]Altitudinal distributions of BDE-209 and other polybromodiphenyl ethers in high mountain lakes Full text
2011
Bartrons, Mireia | Grimalt, Joan O. | Catalan, Jordi
Altitudinal distributions of BDE-209 and other polybromodiphenyl ethers in high mountain lakes Full text
2011
Bartrons, Mireia | Grimalt, Joan O. | Catalan, Jordi
The present study shows the occurrence of 2,2′,3,3′,4,4′,5,5′,6,6′-decabromodiphenyl ether (BDE-209) in microbial biofilms of Pyrenean and Tatra high mountain lakes despite its low vapor pressure and high hydrophobicity. Aerosol air transport is therefore a feasible mechanism for BDE-209 accumulation in sites up to 2688 m above sea level. This compound and other PBDEs exhibit altitudinally-dependent distribution involving higher concentrations with increasing mountain lake elevation. However, the apparently very high enthalpies of the concentration gradients observed, including BDE-209, suggest that bacterial anaerobic debromination also plays a significant role in the resulting altitudinal distributions. This microbial mechanism explains the relative abundances of PBDEs and their within lake differences between rocky and sediment microbial biofilms, thereby showing that the altitudinal pattern observed is not purely due to water temperature control on bacterial activity but also to changes in the availability of anaerobic microenvironments which increase with increasing lake productivity at lower altitudes.
Show more [+] Less [-]Altitudinal distributions of BDE-209 and other polybromodiphenyl ethers in high mountain lakes Full text
2011
Bartrons, Mireia | Grimalt, Joan O. | Catalán, Jordi
24 páginas, 3 tablas, 4 figuras. | The present study shows the occurrence of 2,2′,3,3′,4,4′,5,5′,6,6′-decabromodiphenyl ether (BDE-209) in microbial biofilms of Pyrenean and Tatra high mountain lakes despite its low vapor pressure and high hydrophobicity. Aerosol air transport is therefore a feasible mechanism for BDE-209 accumulation in sites up to 2688 m above sea level. This compound and other PBDEs exhibit altitudinally-dependent distribution involving higher concentrations with increasing mountain lake elevation. However, the apparently very high enthalpies of the concentration gradients observed, including BDE-209, suggest that bacterial anaerobic debromination also plays a significant role in the resulting altitudinal distributions. This microbial mechanism explains the relative abundances of PBDEs and their within lake differences between rocky and sediment microbial biofilms, thereby showing that the altitudinal pattern observed is not purely due to water temperature control on bacterial activity but also to changes in the availability of anaerobic microenvironments which increase with increasing lake productivity at lower altitudes. Capsule: Decabromodiphenyl ether and the other polybromodiphenyl congeners show vertical distributions in high mountains due to temperature effects and microbial degradation. | This work has been supported by the EU Projects Euro-Limpacs (GOCE-CT-2003- 505540) and ArcRisk (FP7-ENV-2008-1-226534), Spanish MEC project Trazas (CGL2004-02989) and Consolider Ingenio “GRACCIE” program (CSD2007-00067). Technical assistance in instrumental analysis by R. Chaler, D. Fanjul, and R. Mas, analytical advice by J. López and P. Fernández, field help by L. Camarero, M. Bacardit, G. Mendoza, E. Gallego, and S. Jarque is acknowledged. One of the authors, M.B., thanks a FPU grant of the Spanish Ministry of Education and Science. | Peer reviewed
Show more [+] Less [-]DNA damage in caged Gammarus fossarum amphipods: A tool for freshwater genotoxicity assessment Full text
2011
Lacaze, Emilie | Devaux, Alain | Mons, Raphaël | Bony, Sylvie | Garric, Jeanne | Geffard, Alain | Geffard, Olivier
DNA damage in caged Gammarus fossarum amphipods: A tool for freshwater genotoxicity assessment Full text
2011
Lacaze, Emilie | Devaux, Alain | Mons, Raphaël | Bony, Sylvie | Garric, Jeanne | Geffard, Alain | Geffard, Olivier
The aim of this study was to propose a tool for freshwater environmental genotoxicity assessment using Gammarus fossarum, a high ecologically relevant species. In a first part, gammarids were caged upstream and downstream wastewater treatment plant effluent output. The sensitivity of genotoxic responses of haemocytes, oocytes and spermatozoa was compared using the Comet assay. Spermatozoa appeared to be the most sensitive, suitable and relevant cell type for genotoxicity risk assessment. In a second part, a watershed-scale study was conducted over 2 years to evaluate the applicability of our caging procedure. The genotoxic impact of a contamination was followed, taking into account seasonal variability. DNA damage in spermatozoa exhibited low basal level and low variability in control upstream sites, providing a reliable discrimination of polluted sites. Finally, DNA damage in caged G. fossarum has been proved to be a sensitive and reproducible tool for freshwater genotoxicity assessment.
Show more [+] Less [-]DNA damage in caged Gammarus fossarum amphipods: A tool for freshwater genotoxicity assessment Full text
2011
Lacaze, Emilie | Devaux, Alain | Mons, Raphaël | Bony, Sylvie | Garric, Jeanne | Geffard, Alain | Geffard, Olivier | Milieux aquatiques, écologie et pollutions (UR MALY) ; Institut national de recherche en sciences et technologies pour l'environnement et l'agriculture (IRSTEA) | Laboratoire d'Ecologie des Hydrosystèmes Naturels et Anthropisés (LEHNA) ; Université Claude Bernard Lyon 1 (UCBL) ; Université de Lyon-Université de Lyon-École Nationale des Travaux Publics de l'État (ENTPE)-Centre National de la Recherche Scientifique (CNRS) | Équipe 5 - Impacts des Polluants sur les Écosystèmes (LEHNA IPE) ; Laboratoire d'Ecologie des Hydrosystèmes Naturels et Anthropisés (LEHNA) ; Université Claude Bernard Lyon 1 (UCBL) ; Université de Lyon-Université de Lyon-École Nationale des Travaux Publics de l'État (ENTPE)-Centre National de la Recherche Scientifique (CNRS)-Université Claude Bernard Lyon 1 (UCBL) ; Université de Lyon-Université de Lyon-École Nationale des Travaux Publics de l'État (ENTPE)-Centre National de la Recherche Scientifique (CNRS) | Laboratoire d'Eco-Toxicologie ; Université de Reims Champagne-Ardenne (URCA)
International audience | The aim of this study was to propose a tool for freshwater environmental genotoxicity assessment using Gammarus fossarum, a high ecologically relevant species. In a first part, gammarids were caged upstream and downstream wastewater treatment plant effluent output. The sensitivity of genotoxic responses of haemocytes, oocytes and spermatozoa was compared using the Comet assay. Spermatozoa appeared to be the most sensitive, suitable and relevant cell type for genotoxicity risk assessment. In a second part, a watershed-scale study was conducted over 2 years to evaluate the applicability of our caging procedure. The genotoxic impact of a contamination was followed, taking into account seasonal variability. DNA damage in spermatozoa exhibited low basal level and low variability in control upstream sites, providing a reliable discrimination of polluted sites. Finally, DNA damage in caged G. fossarum has been proved to be a sensitive and reproducible tool for freshwater genotoxicity assessment. (C) 2011 Elsevier Ltd. All rights reserved.
Show more [+] Less [-]Occurrence of arsenic in brown rice and its relationship to soil properties from Hainan Island, China Full text
2011
Fu, Yangrong | Chen, Mulong | Bi, Xiangyang | He, Yusheng | Ren, Limin | Xiang, Wu | Qiao, Shengying | Yan, Sen | Li, Zhonggen | Ma, Zhendong
The acquaintance of arsenic concentrations in rice grain is vital in risk assessment. In this study, we determined the concentration of arsenic in 282 brown rice grains sampled from Hainan Island, China, and discussed its possible relationships to the considered soil properties. Arsenic concentrations in the rice grain from Hainan Island varied from 5 to 309 μg/kg, with a mean (92 μg/kg) lower than most published data from other countries/regions and the maximum contaminant level (MCL) for Asᵢ in rice. The result of correlation analysis between grain and soil properties showed that grain As concentrations correlated significantly to soil arsenic speciation, organic matter and soil P contents and could be best predicted by humic acid bound and Fe–Mn oxides bound As fractions. Grain arsenic rises steeply at soil As concentrations lower than 3.6 mg/kg and gently at higher concentrations.
Show more [+] Less [-]Occurrence of polycyclic aromatic hydrocarbons in surface sediments of a highly urbanized river system with special reference to energy consumption patterns Full text
2011
Zhang, Kai | Wang, Ji-Zhong | Liang, Bo | Zeng, E. Y. (Eddy Y.)
Sediment samples collected from downstream of the Dongjiang River, a highly urbanized river network within the Pearl River Delta of South China, were analyzed for 28 polycyclic aromatic hydrocarbons (PAHs). Total concentrations of 28 PAHs, 16 priority PAHs designated by the United States Environmental Protection Agency (USEPA) and the seven carcinogenic PAHs classified by the USEPA ranged from 480 to 4600, 100 to 3400 and 10 to 1700 ng/g dry weight, respectively. Principal component analysis-based stepwise multivariate linear regression showed that sediment PAHs were predominantly derived from coal combustion, refined fossil fuel combustion and oil spills, accounting for 37%, 32% and 23%, respectively, of the total loading. The levels of sediment PAHs remained steady from 2002 to 2008, during which fossil fuel consumption had doubled, probably reflecting efforts to control PAH emissions from fossil fuel combustion. Finally, use of natural gas and liquefied petroleum gas in automobiles should be encouraged to improve environmental quality.
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