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Geomembranes (GMs) are widely used in hydraulic applications. Unfortunately, some additives contained in GMs are extracted upon prolonged contact with water or soil. Depending on their chemical nature, additives contained within GMs or degradation products thereof may affect natural ecosystems. To better understand this effect, the present study evaluates the potential impact of additives extracted from GMs that are commonly used in hydraulic applications. The approach consists of identifying additives contained in both unaged and aged high-density polyethylene and polypropylene GMs. Next, these GMs are immersed for various time intervals at 80, 55, and 25 °C in aqueous solutions (pH 4 and 7), and the chemical composition of the resulting solution is analyzed by ultraviolet absorbance spectroscopy. In addition, the effect of these solutions containing the GM extracts on the growth of Chlorella vulgaris and on the swimming of Daphnia sp . is studied. The first few days of exposure to the extracted molecules negatively impact C. vulgaris growth and Daphnia sp. swimming behavior. However, after prolonged exposure, the impact is reversed and microalgae growth is stimulated instead. This result may be related to the change of the nature of the molecules detected by UV spectroscopy. [ABSTRACT FROM AUTHOR]

In this study isotopic tracing using 13 C labelled pentachlorophenol (PCP) and 2,4,6-trichlorophenol (2,4,6-TCP) is proposed as a tool to distinguish the loss of PCP and 2,4,6-TCP due to biodegradation from other physical processes. This isotopic approach was applied to accurately assess in situ PCP and 2,4,6-TCP degradation under methanogenic conditions in several microcosms made up of household waste. These microcosms were incubated in anaerobic conditions at 35 °C (mesophilic) and 55 °C (thermophilic) without agitation. The volume of biogas produced (CH 4 and CO 2 ), was followed for a period of 130 days. At this stage of stable methanogenesis, 13 C 6 -PCP and 13 C 6 -2,4,6-TCP were introduced anaerobically in microcosms and its monitoring at mesophilic and thermophilic conditions was performed in parallel by gas chromatography mass spectrometry (GC–MS) and gas chromatography isotope-ratio mass spectrometry (GC–IRMS). This study proved the almost total dechlorination of bioavailable PCP and 2,4,6-TCP into 4-CP at 35 °C. Nevertheless, high rate adsorption in particular materials of the two compounds was observed. Furthermore, Carbon-13 Nuclear Magnetic Resonance ( 13 C-NMR) Spectroscopy analysis of 13 C labelled 2,4,6-TCP mesophilic incubations showed the partial mineralization of 4-CP at 35 °C to acetate and then to HCO 3− . Consequently, NMR results confirm the biogas isotopic results indicating the mineralization of 13 C labelled 2,4,6-TCP into 13 C (CH 4 and CO 2 ). Concerning 13 C labelled PCP mesophilic incubations, the isotopic composition of the biogas still natural until the day 262. In contrast, no dechlorination was observed at 55 °C. Thus PCP and 2,4,6-TCP were persistent in thermophilic conditions. [ABSTRACT FROM AUTHOR]

A headspace solid-phase microextraction (HS-SPME) coupled with gas chromatography-mass spectrometry (GC-MS) automatic method for simultaneous determination of trace amounts of phenol, methylphenols (MPs), chlorophenols (CPs) and bisphenol-A (BPA) in water samples and industrial effluents has been developed. Prior to SPME extraction, a direct derivatisation step using acetic anhydride was performed. Four different SPME fibre coatings (75 µm CAR-PDMS, 65 µm PDMS-DVB, 100 µm PDMS and 85 µm PA) were tested. The parameters affecting the HS-SPME process and derivatisation step studied were: extraction time (5-60 min) and temperature (40-100°C), derivatisation time (5-10 min), sample agitation (0-500 rpm), addition of sodium chloride (0-40%). The GC-MS quantification was performed by internal standard calibration and the limits of detection (LODs) were in the low ng L-1. The proposed analytical procedure provided a good linearity (r2 > 0.9931) for standard solutions and a repeatability ranging from 4.8 to 15.2% (n = 5). The obtained results show that the developed method was rapid, simple and efficient for phenol, MPs, CPs and BPA analysis, and provides a good alternative to SPE and LLE. Finally, the proposed method has been applied successfully to analyse water samples, municipal solid waste landfill and industrial effluents. [ABSTRACT FROM AUTHOR]

Abstract: In this paper, the isotopic tracing using 13C-labeled phenol and bisphenol A was used to study their biodegradation during anaerobic digestion of municipal solid waste. Microcosms were incubated anaerobically at 35°C (mesophilic conditions) and 55°C (thermophilic conditions) without steering. A continuous follow-up of the production of biogas (CH4 and CO2), was carried out during 130d until the establishment of stable methanogenesis. Then 13C12-BPA, and 13C6-phenol were injected in microcosms and the follow-up of their degradation was performed simultaneously by gas chromatography isotope-ratio mass spectrometry (GC–IRMS) and gas chromatography mass spectrometry (GC–MS). Moreover, Carbon-13 Nuclear Magnetic Resonance (13C-NMR) Spectroscopy is used in the identification of metabolites. This study proves that the mineralization of phenol to CO2 and CH4 occurs during anaerobic digestion both in mesophilic and thermophilic conditions with similar kinetics. In mesophilic condition phenol degradation occurs through the benzoic acid pathway. In thermophilic condition it was not possible to identify the complete metabolic pathway as only acetate was identified as metabolite. Our results suggest that mineralization of phenol under thermophilic condition is instantaneous explaining why metabolites are not observed as they do not accumulate. No biodegradation of BPA was observed. [Copyright &y& Elsevier]

Omics longitudinal studies are effective experimental designs to inform on the stability and dynamics of microbial communities in response to perturbations, but time-course analytical frameworks are required to fully exploit the temporal information acquired in this context. In this study we investigate the influence of ammonia on the stability of anaerobic digestion (AD) microbiome with a new statistical framework. Ammonia can severely reduce AD performance. Understanding how it affects microbial communities development and the degradation progress is a key operational issue to propose more stable processes. Thirty batch digesters were set-up with different levels of ammonia. Microbial community structure and metabolomic profiles were monitored with 16 S-metabarcoding and GCMS (gas-chromatography-mass-spectrometry). Digesters were first grouped according to similar degradation performances. Within each group, time profiles of OTUs and metabolites were modelled, then clustered into similar time trajectories, evidencing for example a syntrophic interaction between Syntrophomonas and Methanoculleus that was maintained up to 387 mg FAN/L. Metabolites resulting from organic matter fermentation, such as dehydroabietic or phytanic acid, decreased with increasing ammonia levels. Our analytical framework enabled to fully account for time variability and integrate this parameter in data analysis. [Display omitted] • A novel time-course statistical framework was used for omics longitudinal data. • Similar temporal dynamics between microorganisms and metabolites were identified. • Successive growth of guilds of microorganisms across time was revealed. • Microbial dynamics under different ammonia levels were compared. • The influence of ammonia on degradation rate differs between identified metabolites. [ABSTRACT FROM AUTHOR]

The European Directive 2000/60/CE delineates the objectives of a good ecological and chemical status for rivers to achieve before 2015. The present project focuses on a pond-reservoir system (later referred to as a constructed wetland, CW), which can be used as a buffering system to lower the impact of agricultural practices on hydrosystems and decrease or limit the transfer of contaminants flowing toward surface waters. The CW studied is located at Aulnoy, 70 km northeast of Paris (France). The aim was to assess the efficiency of a CW in terms of nitrate removal and analyze the hydrological balance of the CW and the agricultural catchment. This study showed potential nitrate removal based on a decrease in average nitrate contents measured over a period of 8 years between the inlet and the outlet of the CW. Average values of 12.6 14 and 6.4 mg N–NO 3 /L, respectively, were measured at the main drain, the spring and the reservoir; this led to a 50 ± 18% (mean ± standard deviation) reduction of nitrate fluxes. The semi-potential denitrification experiments confirmed the denitrification capacity of CW sediments. Conclusively, this CW can treat waters from agricultural drainage, producing outflow quality in line with the expectations of a good ecological status as defined by the European Directive 2000/60/CE. [ABSTRACT FROM AUTHOR]

• Single and combined effects of imidacloprid and chlorpyrifos are assessed in gammarids. • The insecticides elicit biological effects at different organizational levels. • Individual performances and cellular functions are altered at field exposure levels. • These sublethal responses are promising early endpoints for risk assessment. • Insecticide mixture-elicited lethality highlights their harmful feature for wildlife. Aquatic media are ultimate recipients of various contaminants including pesticides pervasively applied in agrosystems. Characterizing the ecotoxicity of pesticides and their mixtures to aquatic wildlife at field-realistic levels is thus crucial for environmental risk assessment. This study aims at assessing the effects of two current-use insecticides, imidacloprid and chlorpyrifos, on Gammarus fossarum using multi-level biomarkers. In microcosms, gammarids were exposed for 72 h to insecticides tested individually or in mixture at 0.01, 0.1 and 1 μg/L of each chemical. Multi-metric responses were assessed at the individual level (behavioural traits: locomotion, respiration and amplexus formation) and the cellular level (enzymes involved in growth, moulting, digestion and cell stress). The results showed insecticide-elicited behavioural and biochemical responses from the lowest concentration of 0.01 μg/L. Overall, single exposures stimulated behavioural traits and inhibited enzymatic activities, highlighting subtle impacts at different organizational levels but these were not dose related. For binary mixtures, antagonistic effects (i.e. less-than-additive) on biomarkers were mainly observed when compared with single exposures. Multi-variable analyses indicated the complementarity of behavioural and biochemical biomarkers in identifying sublethal biological alterations and dose-dependent multiple action sites of insecticides. Besides, the mortality observed only for the mixture at 1 μg/L demonstrated a high lethal potential of insecticides in a simple binary combination. To conclude, this study demonstrates disturbances in individual performances and cellular impairments occurring at environmentally realistic exposure levels in a non-target wild species. Since the sublethal effects, such as those identified with this multi-biomarker approach, could lead to long-term alterations in population dynamics of agricultural areas, they constitute promising early endpoints for risk assessment of insecticides. [ABSTRACT FROM AUTHOR]

In this paper, the isotopic tracing using (13)C-labeled phenol and bisphenol A was used to study their biodegradation during anaerobic digestion of municipal solid waste. Microcosms were incubated anaerobically at 35 °C (mesophilic conditions) and 55 °C (thermophilic conditions) without steering. A continuous follow-up of the production of biogas (CH(4) and CO(2)), was carried out during 130 d until the establishment of stable methanogenesis. Then (13)C(12)-BPA, and (13)C(6)-phenol were injected in microcosms and the follow-up of their degradation was performed simultaneously by gas chromatography isotope-ratio mass spectrometry (GC-IRMS) and gas chromatography mass spectrometry (GC-MS). Moreover, Carbon-13 Nuclear Magnetic Resonance ((13)C-NMR) Spectroscopy is used in the identification of metabolites. This study proves that the mineralization of phenol to CO(2) and CH(4) occurs during anaerobic digestion both in mesophilic and thermophilic conditions with similar kinetics. In mesophilic condition phenol degradation occurs through the benzoic acid pathway. In thermophilic condition it was not possible to identify the complete metabolic pathway as only acetate was identified as metabolite. Our results suggest that mineralization of phenol under thermophilic condition is instantaneous explaining why metabolites are not observed as they do not accumulate. No biodegradation of BPA was observed., (Copyright © 2012 Elsevier Ltd. All rights reserved.)