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Degradation and bound-residue formation of nonylphenol in red soil and the effects of ammonium
2014
Liu, Jie | Shan, Jun | Jiang, Bingqi | Wang, Lianhong | Yu, Bin | Chen, Jianqiu | Guo, Hongyan | Ji, Rong
Fate of nonylphenol (NP) in soils and the effects of nitrogen fertilizers are unclear. Using 14C-tracer, we studied the aerobic and anaerobic degradation of 4-NP111 in a paddy red soil amended without and with ammonium chloride. Under oxic conditions, 4-NP111 had a half-life of 16.1 ± 1.6 days and minor mineralization (3.84 ± 0.02%), forming no extractable metabolite but abundant bound residues (60.9 ± 1.7%, mostly bound to humin) after 49 days of incubation. The ammonium amendment (8 mmol/kg soil) significantly inhibited the degradation (half-life of 68.0 ± 7.7 days), mineralization (2.0 ± 1.1%), and bound-residue formation (23.7 ± 0.2%). Under anoxic conditions, 4-NP111 did not degrade during 49 days of incubation and the ammonium amendment (40 mmol/kg soil) did not affect its persistence. Our results demonstrate that bound-residue formation was a major mechanism for NP dissipation in the red soil under oxic conditions and that chemical nitrogen fertilizer at average field application rate may already considerably increase NP recalcitrance in agricultural soils.
显示更多 [+] 显示较少 [-]Long-term behaviour of 137Cs in spruce bark in coniferous forests in the Czech Republic
2014
Rulík, Petr | Pilátová, Helena | Suchara, Ivan | Sucharová, Julie
Activity concentrations of 137Cs were detected in more than 400 outer spruce bark samples collected at sites variably affected by Chernobyl fallout across the Czech Republic in 1995 and 2010. The temporal changes in the 137Cs activities were found. The mean effective half-life (TEF) for 137Cs in spruce bark was 9.6 years, and the mean environmental half-life (TE) was 14 years. The effective half-lives were significantly higher in areas with higher long-term annual precipitation sums. Coefficient a in linear regression y = ax + b of half-lives on precipitation sums was 0.015 y mm−1 for TEF and 0.036 y mm−1 for TE. The aggregated transfer factor of 137Cs from soil to bark was determined and the pre-Chernobyl bark contamination related to year 2010 was estimated.
显示更多 [+] 显示较少 [-]Silver, zinc oxide and titanium dioxide nanoparticle ecotoxicity to bioluminescent Pseudomonas putida in laboratory medium and artificial wastewater
2014
Mallevre, Florian | Fernandes, Teresa F. | Aspray, Thomas J.
Bacteria based ecotoxicology assessment of manufactured nanoparticles is largely restricted to Escherichia coli bioreporters in laboratory media. Here, toxicity effects of model OECD nanoparticles (Ag NM-300K, ZnO NM-110 and TiO2 NM-104) were assessed using the switch-off luminescent Pseudomonas putida BS566::luxCDABE bioreporter in Luria Bertani (LB) medium and artificial wastewater (AW). IC50 values ∼4 mg L−1, 100 mg L−1 and >200 mg L−1 at 1 h were observed in LB for Ag NM-300K, ZnO NM-110 and TiO2 NM-104, respectively. Similar results were obtained in AW for Ag NM-300K (IC50 ∼5 mg L−1) and TiO2 NM-104 (IC50 >200 mg L−1) whereas ZnO NM-110 was significantly higher (IC50 >200 mg L−1). Lower ZnO NM-110 toxicity in AW compared to LB was associated with differences in agglomeration status and dissolution rate. This work demonstrates the importance of nanoecotoxicological studies in environmentally relevant matrices.
显示更多 [+] 显示较少 [-]Occurrences and fate of DDT principal isomers/metabolites, DDA, and o,p'-DDD enantiomers in fish, sediment and water at a DDT-impacted superfund site
2014
Garrison, A.W. | Cyterski, M. | Roberts, K.D. | Burdette, D. | Williamson, J. | Avants, J.K.
In the 1950s and 60s, discharges from a DDT manufacturing plant contaminated a tributary system of the Tennessee River near Huntsville, Alabama, USA. Regulatory action resulted in declaring the area a Superfund site which required remediation and extensive monitoring. Monitoring data collected from 1988, after remediation, through 2011 showed annual decreases approximating first-order decay in concentrations of total DDT and its six principal congeners (p,p'-DDT, o,p'-DDT, p,p'-DDD, o,p'-DDD, p,p'-DDE and o,p'-DDE) in filets from three species of fish. As of 2013, these concentrations met the regulatory requirements of 5 mg/kg or less total DDT for each fish tested. The enantiomer fractions (EF) of chiral o,p'-DDD in smallmouth buffalo and channel catfish were always below 0.5, indicating preferential decay of the (+)-enantiomer of this congener; this EF did not change significantly over 15 years. The often-neglected DDT metabolite p,p'-DDA was found at a concentration of about 20 μg/l in the ecosystem water.
显示更多 [+] 显示较少 [-]Microbial formation and degradation of oxygen-containing polycyclic aromatic hydrocarbons (OPAHs) in soil during short-term incubation
2014
Wilcke, Wolfgang | Kiesewetter, Mario | Musa Bandowe, Benjamin A.
We tested whether OPAHs were formed during 19-wk incubation of a fertile soil at optimum moisture in the dark. The soil had initial mean (±s.e., n = 3) concentrations of 22 ± 1.7 (Σ28PAHs) and 4.2 ± 0.34 μg g−1 (Σ14OPAHs). After 19 wk, individual PAH and OPAH concentrations had decreased by up to 14 and 37%, respectively. Decreases in % of initial concentrations were positively correlated with their KOW values for PAHs (r = 0.48, p = 0.022) and 9 OPAHs (r = 0.78, p = 0.013) but negatively, albeit not significantly, for 5 OPAHs (r = −0.75, p = 0.145) suggesting net formation of some OPAHs. The latter was supported by significantly increasing 1-indanone/fluorene ratios while the other OPAH to parent-PAH ratios remained constant or tended to increase. We conclude that OPAHs are formed in soils during microbial turnover of PAHs in a short time.
显示更多 [+] 显示较少 [-]Adsorption of polar, nonpolar, and substituted aromatics to colloidal graphene oxide nanoparticles
2014
Wang, Fang | Haftka, Joris J.-H. | Sinnige, Theo L. | Hermens, Joop L.M. | Chen, Wei
We conducted batch adsorption experiments to understand the adsorptive properties of colloidal graphene oxide nanoparticles (GONPs) for a range of environmentally relevant aromatics and substituted aromatics, including model nonpolar compounds (pyrene, phenanthrene, naphthalene, and 1,3-dichlorobenzene) and model polar compounds (1-naphthol, 1-naphthylamine, 2,4-dichlorophenol, and 2,4-dinitrotoluene). GONPs exhibited strong adsorption affinities for all the test compounds, with distribution coefficients on the order of 103–106 L/kg. Adsorption to GONPs is much more linear than to carbon nanotubes (CNTs) and C60, likely because GO nanoflakes are essentially individually dispersed (rendering adsorption sites of similar adsorption energy) whereas CNT/C60 are prone to bundling/aggregation. For a given compound GONPs and CNTs often exhibit different adsorption affinities, which is attributable to the differences in both the morphology and surface chemistry between the two nanomaterials. Particularly, the high surface O-content of GONPs enables strong H-bonding and Lewis acid–base interactions with hydroxyl- and amino-substituted aromatics.
显示更多 [+] 显示较少 [-]Spatio-temporal trends of nitrogen deposition and climate effects on Sphagnum productivity in European peatlands
2014
Granath, Gustaf | Limpens, Juul | Posch, Maximilian | Mücher, Sander | de Vries, Wim
To quantify potential nitrogen (N) deposition impacts on peatland carbon (C) uptake, we explored temporal and spatial trends in N deposition and climate impacts on the production of the key peat forming functional group (Sphagnum mosses) across European peatlands for the period 1900–2050. Using a modelling approach we estimated that between 1900 and 1950 N deposition impacts remained limited irrespective of geographical position. Between 1950 and 2000 N deposition depressed production between 0 and 25% relative to 1900, particularly in temperate regions. Future scenarios indicate this trend will continue and become more pronounced with climate warming. At the European scale, the consequences for Sphagnum net C-uptake remained small relative to 1900 due to the low peatland cover in high-N areas. The predicted impacts of likely changes in N deposition on Sphagnum productivity appeared to be less than those of climate. Nevertheless, current critical loads for peatlands are likely to hold under a future climate.
显示更多 [+] 显示较少 [-]Release of cadmium, copper and lead from urban soils of Copenhagen
2014
Li, Lijun | Holm, Peter E. | Marcussen, Helle | Bruun Hansen, Hans Christian
We studied the bonding and release kinetics of Cd, Cu and Pb from different soils in the older metropolitan area of Copenhagen. Total Cd, Cu and Pb concentrations were elevated 5–27 times in the urban soils compared to an agricultural reference soil, with Cd and Pb in mainly mobilisable pools and Cu in strongly bound pools. The soils were subjected to accelerated leaching studies in Ca(NO3)2 or HNO3 solutions resulting in release up to 78, 18 and 15% of total Cd, Cu and Pb soil concentrations over a period of 15 weeks. The relative initial Cd and Pb release rates increased 10 fold when pH decreased 2 and 3 units, respectively, while increases in Cu release rates were only seen at pH below 4. The total leachable Cu and Pb pools were higher in urban soils compared the agricultural reference soil but not for Cd.
显示更多 [+] 显示较少 [-]The impact of bioaugmentation on dechlorination kinetics and on microbial dechlorinating communities in subsurface clay till
2014
Bælum, Jacob | Scheutz, Charlotte | Chambon, Julie C. | Jensen, Christine Mosegaard | Brochmann, Rikke P. | Dennis, Philip | Laier, Troels | Broholm, Mette M. | Bjerg, Poul L. | Binning, Philip J. | Jacobsen, Carsten S.
A molecular study on how the abundance of the dechlorinating culture KB-1 affects dechlorination rates in clay till is presented. DNA extracts showed changes in abundance of specific dechlorinators as well as their functional genes. Independently of the KB-1 added, the microbial dechlorinator abundance increased to the same level in all treatments. In the non-bioaugmented microcosms the reductive dehalogenase gene bvcA increased in abundance, but when KB-1 was added the related vcrA gene increased while bvcA genes did not increase. Modeling showed higher vinyl-chloride dechlorination rates and shorter time for complete dechlorination to ethene with higher initial concentration of KB-1 culture, while cis-dichloroethene dechlorination rates were not affected by KB-1 concentrations. This study provides high resolution abundance profiles of Dehalococcoides spp. (DHC) and functional genes, highlights the ecological behavior of KB-1 in clay till, and reinforces the importance of using multiple functional genes as biomarkers for reductive dechlorination.
显示更多 [+] 显示较少 [-]Mercury exposure in a large subantarctic avian community
2014
Carravieri, Alice | Cherel, Yves | Blévin, Pierre | Brault-Favrou, Maud | Chastel, Olivier | Bustamante, Paco
Mercury (Hg) contamination poses potential threats to ecosystems worldwide. In order to study Hg bioavailability in the poorly documented southern Indian Ocean, Hg exposure was investigated in the large avian community of Kerguelen Islands. Adults of 27 species (480 individuals) showed a wide range of feather Hg concentrations, from 0.4 ± 0.1 to 16.6 ± 3.8 μg g−1 dry weight in Wilson's storm petrels and wandering albatrosses, respectively. Hg concentrations increased roughly in the order crustacean- < fish- ≤ squid- ≤ carrion-consumers, confirming that diet, rather than taxonomy, is an important driver of avian Hg exposure. Adults presented higher Hg concentrations than chicks, due to a longer duration of exposure, with the only exception being the subantarctic skua, likely because of feeding habits' differences of the two age-classes in this species. High Hg concentrations were reported for three species of the poorly known gadfly petrels, which merit further investigation.
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