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Influence of the nature of soil organic matter on the sorption behaviour of pentadecane as determined by PLS analysis of mid-infrared DRIFT and solid-state 13C NMR spectra
2010
Ehlers, G.A Clark | Forrester, Sean T. | Scherr, Kerstin E. | Loibner, Andreas P. | Janik, L. J. (Les J)
The nature of soil organic matter (SOM) functional groups associated with sorption processes was determined by correlating partitioning coefficients with solid-state 13C nuclear magnetic resonance (NMR) and diffuse reflectance mid-infrared (DRIFT) spectral features using partial least squares (PLS) regression analysis. Partitioning sorption coefficients for n-pentadecane (n-C15) were determined for three alternative models: the Langmuir model, the dual distributed reactive domain model (DRDM) and the Freundlich model, where the latter was found to be the most appropriate. NMR-derived constitutional descriptors did not correlate with Freundlich model parameters. By contrast, PLS analysis revealed the most likely nature of the functional groups in SOM associated with n-C15 sorption coefficients (KF) to be aromatic, possibly porous soil char, rather than aliphatic organic components for the presently investigated soils. High PLS cross-validation correlation suggested that the model was robust for the purpose of characterising the functional group chemistry important for n-C15 sorption. NMR/IR spectroscopy and chemometrics reveal the aromatic fraction of soil organic matter being responsible for alkane sorption.
Show more [+] Less [-]Influence of anthropogenic stress on fitness and behaviour of a key-species of estuarine ecosystems, the ragworm Nereis diversicolor
2010
Mouneyrac, C. | Perrein-Ettajani, H. | Amiard-Triquet, C.
Fitness, (biometric measurements, reproduction) and behaviour that are ecologically relevant biomarkers in assessing the quality of estuarine sediments were studied by comparing the responses of the polychaete worm Nereis diversicolor – a key species in estuaries – along a pollution gradient. Intersite differences were shown for all the measured parameters: size–weight relationships, energy reserves as glycogen and lipids, sexual maturation patterns, total number of oocytes per female, total and relative fecundity, burrowing behaviour. The physiological and behavioural status of N. diversicolor was consistently disturbed in the larger, most contaminated estuaries (Loire and Seine, Fr.) compared to reference sites (Bay of Bourgneuf, Goyen estuary, Fr.). Many classes of potentially toxic chemicals present in these estuaries most likely contribute to these impairments but food availability may act as a confounding factor, interfering with the potential impact of contaminants. Fitness, and behaviour in Nereis diversicolor are affected by anthropogenic pressure.
Show more [+] Less [-]Hormetic effect(s) of tetracyclines as environmental contaminant on Zea mays
2010
Migliore, Luciana | Godeas, Feliciana | De Filippis, Stefania Paola | Mantovi, Paolo | Barchi, Davide | Testa, Cecilia | Rubattu, Nicolino | Brambilla, Gianfranco
Animal wastes from intensive pig farming as fertilizers may expose crops to antimicrobials. Zea mays cultivations were carried out on a virgin field, subjected to dressing with pig slurries contaminated at 15 mg L−1 of Oxy- and 5 mg L−1 of Chlor-tetracycline, and at 8 mg L−1 of Oxy and 3 mg L−1 of Chlor, respectively. Pot cultivation was performed outdoor (Oxy in the range 62.5–1000 ng g−1 dry soil) and plants harvested after 45 days. Tetracyclines analyses on soils and on field plants (roots, stalks, and leaves) did not determine the appreciable presence of tetracyclines. Residues were found in the 45-day pot corn only, in the range of 1–50 ng g−1 for Oxy in roots, accounting for a 5% carry-over rate, on average. Although no detectable residues in plants from on land cultivations, both experimental batches showed the same biphasic growth form corresponding to a dose/response hormetic curve. Oxytetracycline in soils elicits a hormetic response in Zea mays plants.
Show more [+] Less [-]3-Way pattern-recognition of PAHs from Galicia (NW Spain) seawater samples after the Prestige's wreck
2010
Grueiro-Noche, G. | Andrade, J.M. | Muniategui-Lorenzo, S. | López-Mahía, P. | Prada-Rodríguez, D.
In November 2002 the oil tanker ‘Prestige’ released 65 000 tons of a heavy fuel oil throughout the Galician coastline (NW Spain), causing extensive damage to marine life, natural resources and economic activities at Northern Portugal, Spain and SW France. To evaluate the impact of the oil spill on the aquatic system, 30 polycyclic aromatic hydrocarbons (PAHs), including alkylated derivatives, were analyzed in seawater on five different sampling campaigns from 2002 to 2004. Sampling was made along the Galician continental shelf. In each station three samples were collected at three different depths (surface, mid-depth and bottom). Four different approaches for 3-way analyses (Catenated-PCA, Matrix-Augmented Principal Components Analysis, Parallel Factor Analysis and Procrustes rotation) have been used to asses the major sources of PAHs into the seawater. They revealed two main pollution patterns: one related to oil spillages and discharge of petroleum products, and another more associated with a diffuse anthropogenic origin. Oil- and anthropogenic-related sources of PAHs were found in a survey program in Galicia after the Prestige wreck, the latter being more relevant as time went by.
Show more [+] Less [-]Time trends of perfluorinated compounds from the sediment core of Tokyo Bay, Japan (1950s-2004)
2010
Zushi, Yasuyuki | Tamada, Masafumi | Kanai, Yutaka | Masunaga, Shigeki
Perfluorinated compounds (PFCs) were detected in sediment core samples collected in Tokyo Bay to reveal their time trends. The core sample deposited during 1950s–2004 was divided into two- to three-year intervals and the concentrations of 24 types of PFCs were determined. Perfluorooctane sulfonate (PFOS) decreased gradually from the early 1990s and its precursor decreased rapidly in the late 1990s, whereas perfluorooctanoic acid (PFOA) increased rapidly. The observed trends were regarded as a reflection of the shift from perfluorooctyl sulfonyl fluoride (PFOSF)-based products to telomer-based products after the phaseout of PFOSF-based products in 2001. The branched isomers of perfluoroundecanoic acid (PFUnDA) and perfluorotridecanoic acid (PFTrDA) were detected in the sample with its ratio of linear-isomer/branched-isomer concentrations decreasing. In this study, we revealed that the sediment core can serve as a tool for reconstructing the past pollution trend of PFCs and can provide interesting evidence concerning their environmental dynamics and time trend. This study reports the time trends of the concentrations of 24 species of PFCs, including FTCA, FTUCA and FOSAA, in a sediment core of Tokyo Bay, Japan. Keywords: Perfluorinated compounds
Show more [+] Less [-]Differential fate of erythromycin and beta-lactam resistance genes from swine lagoon waste under different aquatic conditions
2010
Knapp, Charles W. | Zhang, Wen | Sturm, Belinda S.M. | Graham, David W.
The attenuation and fate of erythromycin-resistance-methylase (erm) and extended-spectrum beta-lactamse (bla) genes were quantified over time in aquatic systems by adding 20-L swine waste to 11,300-L outdoor mesocosms that simulated receiving water conditions below intensive agricultural operations. The units were prepared with two different light-exposure scenarios and included artificial substrates to assess gene movement into biofilms. Of eleven genes tested, only erm(B), erm(F), blaSHV and blaTEM were found in sufficient quantity for monitoring. The genes disappeared rapidly from the water column and first-order water-column disappearance coefficients were calculated. However, detected gene levels became elevated in the biofilms within 2 days, but then disappeared over time. Differences were observed between sunlight and dark treatments and among individual genes, suggesting that ecological and gene-specific factors play roles in the fate of these genes after release into the environment. Ultimately, this information will aid in generating better predictive models for gene fate.
Show more [+] Less [-]Chemical fluxes in time through forest ecosystems in the UK - Soil response to pollution recovery
2010
Vanguelova, E.I. | Benham, S. | Pitman, R. | Moffat, A.J. | Broadmeadow, M. | Nisbet, T. | Durrant, D. | Barsoum, N. | Wilkinson, M. | Bochereau, F. | Hutchings, T. | Broadmeadow, S. | Crow, P. | Taylor, P. | Houston, T Durrant
Long term trend analysis of bulk precipitation, throughfall and soil solution elemental fluxes from 12 years monitoring at 10 ICP Level II forest sites in the UK reveal coherent national chemical trends indicating recovery from sulphur deposition and acidification. Soil solution pH increased and sulphate and aluminium decreased at most sites. Trends in nitrogen were variable and dependant on its form. Dissolved organic nitrogen increased in bulk precipitation, throughfall and soil solution at most sites. Nitrate in soil solution declined at sites receiving high nitrogen deposition. Increase in soil dissolved organic carbon was detected - a response to pollution recovery, changes in soil temperature and/or increased microbial activity. An increase of sodium and chloride was evident - a possible result of more frequent storm events at exposed sites. The intensive and integrated nature of monitoring enables the relationships between climate/pollutant exposure and chemical/biological response in forestry to be explored.
Show more [+] Less [-]Inferring chemical effects on carbon flows in aquatic food webs: Methodology and case study
2010
Laender, Frederik De | Soetaert, K. | Middelburg, J.J.
The majority of ecotoxicological enclosure experiments monitor species abundances at different chemical concentrations. Here, we present a new modelling approach that estimates changes in food web flows from such data and show that population- and food web level effects are revealed that are not apparent from abundance data alone. For the case of cypermethrin in freshwater enclosures, photosynthesis and excretion (d−1) of phytoplankton at 3.643 μg L-1 cypermethrin were 30% lower and 100% higher than in the control, respectively. The ingestion rate of mesozooplankton (d−1) was 6 times higher in the treated enclosures than in the control as food concentration increased with insecticide exposure. With increasing cypermethrin concentrations, nanoflagellates progressively relied on phytoplankton as their main food source, which rendered the food web less stable. We conclude that this tool has excellent potential to analyse the wealth of enclosure data as it only needs species abundance and general constraints.
Show more [+] Less [-]The effect of soil organic matter on fate of polycyclic aromatic hydrocarbons in soil: A microcosm study
2010
Yang, Y. | Tao, S. | Zhang, N. | Zhang, D.Y. | Li, X.Q.
A microcosm study was conducted to address the influences of air-soil partition and sequestration on the fate of polycyclic aromatic hydrocarbons (PAHs) in soil. Sterilized and unsterilized soils with soil organic carbon (SOC) content ranging from 0.23 to 7.06% were incubated in a chamber with six PAHs supplied through air. After 100 d of incubation when the system approached pseudo-steady state, the PAHs concentrations in the unsterilized soils still correlated with SOC significantly, while the association did not exist for those sterilized. The lower degradation rate in the soil with higher SOC was likely the major reason for the association between SOC and PAHs concentrations, while the decreased surface porosity likely suppressed such correlation for the sterilized samples. The results indicated that the sequestration was likely the major mechanism for the accumulation of PAHs in soils, while both of the soil porosity and PAHs properties had observed influences.
Show more [+] Less [-]Characterisation of soluble nitrogen and muscle proteins in wastewater throughout the salting process of codfish (<em>Gadus morhua</em>)
2010
Ferraro, Vincenza | Cruz, Isabel B. | Jorge, Ruben Ferreira | Xavier Malcata, F. | Castro, Paula M.L. | Pintado, Manuela E.
In Portugal, Atlantic codfish (Gadus morhua) is usually consumed after dry salting; this process is carried out by mixing deboned codfish with food-grade marine salt followed by stacking in a tank for 6 days. Along the salting process, codfish incorporates salt as well as it is partially dried by the release of water - up to 22 % (w/w). Currently, this wastewater is treated as a residue not being further valorized. However, the presence of a significant amount of valuable compounds in this rest, such as amino acids and proteins, may allow for valorization opportunities not yet explored. The present work focuses on the identification of the nitrogen-containing compounds present in such wastewater. Total nitrogen (WSN), trichloroacetic acid-soluble nitrogen (TCASN) and phosphotungstic acid-soluble nitrogen (PTASN) were evaluated by the micro-Kjeldahl method; Biuret method was used for total protein determinations and SDS-Page was performed for protein molecular weight screening. The results revealed an increase of WSN, TCASN and PTASN with time, with corresponding values of 3.17 g/L (WSN), 1.62 g/L (TCASN) and 1.16 g/L (PTASN) by the end of the process; the evolution of WSN versus the released water was approximately constant during the salting process, as well as the ratios of TCASN/WSN and PTASN/WSN with values of 51.25 and 36.55 % (w/w) at equilibrium, respectively.
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