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International audience; A new sensitive and selective analytical methodology to quantify glyphosate (GLY), aminomethylphosphonic acid (AMPA), and glufosinate (GLU) in both soil and earthworms (Allolobophora chlorotica) was developed. The extraction and purification methods were optimized. The samples were extracted with various aqueous solutions (HNO3, H2O, KOH and borate buffer) and derivatized with 9-Fluorenylmethyl chloroformate (FMOCCl). To optimize the extraction step, a method to remove the excess FMOCCl was applied based on liquid-liquid extraction with diethyl ether. The purification of derivatized extracts was carried out using XLB solid phase extraction (SPE) cartridges before internal standard quantification by liquid chromatography coupled to tandem mass spectrometry (LC/MS/MS). The elution step was optimized to obtain the best recoveries possible, which was with acidic methanol (1% formic acid) (67% for GLY, 70% for GLU and 65% for AMPA). The extraction and purification method followed by analysis of the two herbicides and AMPA in soils using LC/MS/MS determined limit of quantification (LOQ) values of 0.030mug g(-)(1) for GLY, 0.025mug g(-)(1) for AMPA and 0.020microg g(-)(1) for GLU . For earthworms, LOQ were 0.23mug g(-)(1) for GLY, 0.20mug g(-)(1) for AMPA and 0.12mug g(-)(1) for GLU. . The developed method was applied to determine these compounds in natural soils and earthworms.

International audience; The pesticide risk assessment for earthworms is currently performed using standardized tests, the model species Eisenia fetida, and the analyses of the data obtained are performed with ad hoc statistical tools. We assessed the impact of two fungicides on the entire growth pattern of the earthworm species Aporrectodea caliginosa, which is highly representative of agricultural fields. Individuals of three different ages (from hatching to 56 days old) were exposed to Cuprafor micro(R) (copper oxychloride) and Swing(R) Gold (dimoxystrobin and epoxiconazole). Data were analyzed with an energy-based toxicodynamic model coupled with a toxicokinetic model. The copper fungicide caused a drastic growth inhibition once the no effect concentration (NEC), estimated at 65 mg kg(-1) of copper, was exceeded. The Swing(R) Gold negatively affected the growth with NEC values estimated at 0.387 mg kg(-1) and 0.128 mg kg(-1) for the dimoxystrobin and the epoxiconazole in this fungicide formulation, respectively. The time-profile of the effects on A. caliginosa individuals was fully accounted for by the model, whatever their age of exposure. Furthermore, toxicity data analyses, supported by measurements of fungicide concentrations in earthworm at the end of the experiment, allowed bettering understanding of the mechanisms of action of the fungicides towards earthworm growth.

Methotrexate is an antineoplastic folate analog of high environmental concern, due to its low biodegradability and toxicological properties. This study focused on its photodegradation under two irradiation conditions, aiming to be representative of environment (300–450 nm) and drinking water treatment (254 nm). The photodegradation experiments were conducted at two pH, to vary the methotrexate ionization state and to produce a large variety of transformation products (TPs). The degradation kinetics determined through LC-UV monitoring were contrasted according to pH and irradiation wavelength. However, the quantum yields were independent of ionization state at 254 nm and the changes in kinetics at higher wavelengths were attributed to a change in the degradation mechanism. The TPs formed during the reactions were identified by UHPLC-MS/MS, using both the positive and negative modes. Among the eleven proposed structures, five were described as methotrexate TPs for the first time. The TPs result from N-demethylation, glutamic acid oxidation and C-N cleavage, all of them leading to further degraded photoproducts presenting modified or lost glutamic acid part. This was made possible thanks to the negative mode, which allowed the exploration of the glutamic acid moiety modifications. Cytotoxicity assessment on A549 cancer cells demonstrated that all photoproducts formed at pH 7 were less toxic than the parent compound.

International audience; Critical knowledge gaps about environmental fate and unintentional effects of currently used pesticides (CUPs) hamper the understanding and mitigation of their global impacts on ecological processes. We investigated the exposure of earthworms to 31 multiclass CUPs in an arable landscape in France. We highlighted the presence of at least one pesticide in all soils (n=180) and 92% of earthworms (n=155) both in treated crops and nontreated habitats (hedgerows, grasslands, and cereals under organic farming). Mixtures of at least one insecticide, one herbicide, and one fungicide (> limit of quantification) contaminated 90% of soils and 54% of earthworms at levels that could endanger these nontarget beneficial soil organisms. A high risk of chronic toxicity to earthworms was found (46% of samples) both in treated winter cereals and nontreated habitats considered as refuges. This may alter biodiversity, hinder recovery, and impair ecosystem functions. These results provide essential insights for sustainable agriculture and CUP regulation, and highlight the potential of pesticides as agents of global change.

Background Antibiotic resistance is a major concern for public and environmental health. The role played by the environment in disseminating resistance is increasingly considered, as well as its capacity for mitigation. We reviewed the literature on strategies to control dissemination of antibiotic-resistant bacteria (ARB), antibiotic resistance genes (ARG) and mobile genetic elements (MGE) in the environment. Methods This systematic review focused on three main strategies: (i) restriction of antibiotic use (S1), (ii) treatments of liquid/solid matrices (S2) and (iii) management of natural environment (S3). Articles were collected from seven scientific databases until July 2017 and from Web of Science until June 2018. Only studies reporting measurements of ARB, ARG or MGE in environmental samples were included. An evidence map was drawn from metadata extracted from all studies eligible for S1, S2 and S3. Subsets of studies were assessed for internal and external validity to perform narrative and quantitative syntheses. A meta-analysis was carried out to assess the effects of organic waste treatments (random-effect models). Review findings Nine hundred and thirty-one articles representing 1316 individual studies (n) were eligible for S1 (n = 59), S2 (n = 781) and S3 (n = 476) strategies, respectively. Effects of interventions to control the dissemination of antibiotic resistance in the environment were primarily studied in strategy S2. A partial efficiency of wastewater treatment plants (WWTPs) to reduce antibiotic resistance in treated effluent was reported in 118 high validity studies. In spite of the heterogeneity in published results, the meta-analysis showed that composting and drying were efficient treatments to reduce the relative abundance of ARG and MGE in organic waste, by 84% [65%; 93%] and 98% [80%; 100%], respectively. The effect of anaerobic digestion was not statistically significant (51% reduction [− 2%; 77%]) when organic waste treatments were compared together in the same model. Studies in strategies S1 and S3 mainly assessed the effects of exposure to sources of contamination. For instance, 28 medium/high validity studies showed an increase of antibiotic resistance in aquatic environments at the WWTP discharge point. Some of these studies also showed a decrease of resistance as the distance from the WWTP increases, related to a natural resilience capacity of aquatic environments. Concerning wildlife, nine medium/high validity studies showed that animals exposed to anthropogenic activities carried more ARB. Conclusions and implications Knowledge gaps were identified for the relationship between restriction of antibiotic use and variation of antibiotic resistance in the environment, as well as on possible interventions in situ in natural environment. Organic waste treatments with thermophilic phase (> 50 °C) should be implemented before the use/release of organic waste in the environment. More investigation should be conducted with the datasets available in this review to determine the treatment efficiency on ARG carried by specific bacterial communities.

International audience; The representativeness of laboratory studies of the fate of pesticides in soil in field conditions is questionable. This study aimed at comparing the dissipation and bioavailability to earthworms of two fungicides, dimoxystrobin (DMX) and epoxiconazole (EPX), over 12 months under laboratory and field conditions. In both approaches, the fungicides were applied to the same loamy soil as a formulated mixture at several concentrations. We determined total DMX and EPX concentrations in the soil using exhaustive extraction, their environmental availability using mild extraction and their bioavailability through internal concentrations in exposed earthworms. The initial fungicide application appeared as much better controlled in terms of dose and homogeneity in the laboratory than in the field. One year after application, a similar dissipation rate was observed between the laboratory and field experiments (ca 80% and 60% for DMX and EPX, respectively). Similarly, the ratio of available/total concentrations in soil displayed the same trend whatever the duration and the conditions (field or lab), EPX being more available than DMX. Finally, the environmental bioavailability of the two fungicides to earthworms was heterogeneous in the field, but, in the laboratory, the bioaccumulation was evidenced to be dose-dependent only for DMX. Our findings suggest that the actual fate of the two considered fungicides in the environment is consistent with the one determined in the laboratory, although the conditions differed (e.g., presence of vegetation, endogeic earthworm species). This study allowed better understanding of the fate of the two considered active substances in the soil and underlined the need for more research dedicated to the link between environmental and toxicological bioavailability.

International audience; Traditional constructed wetland designs typically result in variable efficiencies for trace organic contaminant removal. In this work, we used a Box–Behnken experimental design for optimizing the conditions of pH, nitrate concentration, and dissolved organic carbon (DOC) concentration that would maximize the rate of triclosan phototransformation while minimizing the accumulation of toxic byproducts. Triclosan is a frequently detected and toxic antimicrobial agent present in many consumer and industrial products. The results showed that high pH values (9.9) and low DOC concentration (11 mg/L–) would maximize triclosan phototransformation rate while minimizing the accumulation of toxic byproducts. As long as DOC concentrations were larger than 33 mg/L, nitrate concentration did not show a significant effect on triclosan phototransformation rate. The major transformation products detected were 2,4-dichlorophenol and compounds with chemical formulas C12H8Cl2O2 and C12H9ClO3, resulting from a chlorine loss or replacement by a OH group. In addition, 4-chlorocatechol was mainly detected during direct photolysis and 2,8-dichlorodibenzo-p-dioxin was only found during direct photolysis at pH 8. This study showed that wetland efficiency at removing triclosan can theoretically be increased by limiting DOC-contributing factors, e.g., emergent vegetation, and supporting pH-increase processes, e.g., via algae growth or by incorporating alkaline geomedia.

International audience; Ponds are important for their ecological value and for the ecosystem services they provide to human societies, but they are strongly affected by human activities. Peri-urban development, currently one of the most pervasive processes of land use change in Europe, exposes ponds to both urban and agricultural contaminants, causing a potential combination of adverse effects. This study, focused on 12 ponds located in a peri-urban area, has two main objectives: (1) to link the physico-chemical characteristics of the waters and the nature of their contaminants, either organic or mineral, with the human activities around ponds, and (2) to estimate the environmental risk caused by these contaminants. The ponds were sampled during two consecutive years in both spring and in autumn. Although the ponds were distributed over a limited geographical area, their contamination profiles were different and more correlated with the agricultural than the urban land use. In terms of aptitude for biology, half of the ponds were classified in degraded states due to their physico-chemical parameters, but without correlation with the endocrine disrupting activities and the levels of organic pollutants as indicators. The main quantified organic pollutants, however, were pesticides with sufficiently high levels in certain cases to induce an environmental risk exceeding the classical thresholds of risk quotient.

International audience; Recent EFSA (European Food Safety Authority) reports highlighted that the ecological risk assessment of pesticides needed to go further by taking more into account the impacts of chemicals on biodiversity under field conditions. We assessed the effects of two commercial formulations of fungicides separately and in mixture, i.e., Cuprafor Micro® (containing 500 g kg−1 copper oxychloride) at 4 (C1, corresponding to 3.1 mg kg−1 dry soil of copper) and 40 kg ha−1 (C10), and Swing® Gold (50 g L−1 epoxiconazole EPX and 133 g L−1 dimoxystrobin DMX) at one (D1, 5.81 10−2 and 1.55 10−1 mg kg−1 dry soil of EPX and DMX, respectively) and ten times (D10) the recommended field rate, on earthworms at 1, 6, 12, 18 and 24 months after the application following the international ISO standard no. 11268-3 to determine the effects on earthworms in field situations. The D10 treatment significantly reduced the species diversity (Shannon diversity index, 54% of the control), anecic abundance (29% of the control), and total biomass (49% of the control) over the first 18 months of experiment. The Shannon diversity index also decreased in the mixture treatment (both fungicides at the recommended dose) at 1 and 6 months after the first application (68% of the control at both sampling dates), and in C10 (78% of the control) at 18 months compared with the control. Lumbricus terrestris, Aporrectodea caliginosa, Aporrectodea giardi, Aporrectodea longa, and Allolobophora chlorotica were (in decreasing order) the most sensitive species to the tested fungicides. This study not only addressed field ecotoxicological effects of fungicides at the community level and ecological recovery, but it also pinpointed some methodological weaknesses (e.g., regarding fungicide concentrations in soil and statistics) of the guideline to determine the effects on earthworms in field situations.

Organic pollution has become a critical issue worldwide due to the increasing input and persistence of organic compounds in the environment. Iron minerals are potentially able to degrade efficiently organic pollutants sorbed to their surfaces via oxidative or reductive transformation processes. Here, we explored the oxidative capacity of nano-magnetite (Fe3O4) having ∼ 12 nm particle size, to promote heterogeneous Fenton-like reactions for the removal of nalidixic acid (NAL), a recalcitrant quinolone antibacterial agent. Results show that NAL was adsorbed at the surface of magnetite and was efficiently degraded under oxic conditions. Nearly 60% of this organic contaminant was eliminated after 30 min exposure to air bubbling in solution in the presence of an excess of nano-magnetite. X-ray diffraction (XRD) and Fe K-edge X-ray absorption spectroscopy (XANES and EXAFS) showed a partial oxidation of magnetite to maghemite during the reaction, and four byproducts of NAL were identified by liquid chromatography-mass spectroscopy (UHPLC-MS/MS). We also provide evidence that hydroxyl radicals (HO(•)) were involved in the oxidative degradation of NAL, as indicated by the quenching of the degradation reaction in the presence of ethanol. This study points out the promising potentialities of mixed valence iron oxides for the treatment of soils and wastewater contaminated by organic pollutants.

The recycling of biosolids and livestock manure in agriculture may lead to the introduction of antibiotic residues, i.e., parent molecule and transformation products, into amended soils. Their fate in soils can be approached through the assessment of their environmental availability. In this work, the environmental availability of sulfamethoxazole (SMX) and three transformation products (N4-acetyl-SMX, 3-amino-5-methylisoxazole, aniline) was assessed in soils amended with sludge compost or cow manure throughout a three-month incubation, using soft extractions with CaCl2, EDTA or cyclodextrin solutions. First, the freeze-storage of soil samples was shown to decrease the SMX extractability. The SMX extractability depended on the initial concentration, the amendment type and the extracting solution at day 0. From 1.9% up to 63% of the SMX total content was initially extractable. The lowest fractions were quantified in EDTA extracts in which the dissolved organic matter was the most complex and responsible for high matrix effects in mass spectrometry compared to CaCl2 extracts. The purification of cyclodextrin extracts highly reduced the matrix effects, but CaCl2 was considered as the most suitable extractant. SMX extractability strongly decreased after the first 8days of incubation to finally reach 0.4-0.8% after 84days, whatever the initial conditions. This high decrease could be related to humification observed through the increasing complexity of extracted dissolved organic matter. Very low levels of transformation products were quantified throughout the incubation period. The low environmental availability of SMX was mainly due to its sorption on soil organic matter and resulted in its low biotransformation in these amended soils.

Agricultural practices such as crop rotation affect soil physical, chemical and biological properties. Legumes crop effect has been shown to provide several agro-ecological services as a cereal previous crop. The aim of the present field study was to estimate the middle term effects of introducing faba bean in crop rotation on the structure and function of soil microbial communities. Two experimental rotation systems were tested (i) Wheat-Beet-Faba Bean-Rape-Wheat (Leg+) and (ii) Wheat-Flax-Wheat-Beet-Wheat (Leg−). Soil samples were collected on tilled plots at 0–10 cm depth on July 2013 under wheat. Soil microbial biomass and soil enzymatic activities (β-glucosidase, cellulase, urease and arylamidase activities) were assessed. Soil microbial diversity was evaluated with two complementary approaches: Phospholipid fatty acid profiling (PLFA) and the metabolic capabilities of the microbial community (Biolog Ecoplates). Soil organic carbon and total nitrogen were significantly and respectively 1.5 and 1.3 times higher in faba bean's rotation compared to free faba bean rotation. Soil microbial biomass did not differ significantly between the two rotations. In general, Leg+ rotation resulted in the greatest carbon mineralization and β-glucosidase and arylamidase activities. The analysis of Biolog data and PLFA profiling indicated that the rotation including faba bean has modified microbial populations and induced differences in the catabolic capability of soil microbial communities. Our results suggested that changing rotation crop by introducing faba bean two years before wheat modifies the surrounding habitat of microbial communities by providing available carbon and nitrogen as well as suitable soil pH. This new habitat could impact the structure of microbial communities and their functions. Leg + rotation seems to be a suitable practice promoting microbial activities in agricultural plots.

In soil, the determination of total concentration using an exhaustive extraction method is not relevant to evaluate the exposure of an organism to a chemical, because of sorption processes. However, little attention has been paid to the bioavailability of organic contaminants to earthworms, and to their effect on sensitive earthworm species found in cultivated fields, such as Aporrectodea icterica [1]. As ecosystem engineers, earthworms influence soil structure and chemistry and are thus key-organisms for the health of terrestrial ecosystems. However, they can be threatened by contaminants such as the fungicide epoxiconazole, which is persistent in soil and presents a chronic toxicity even towards a resistant earthworm species (Eisenia fetida) at a concentration close to the recommended dose. This study aimed to propose a mild extraction method to evaluate the bioavailability of the fungicide epoxiconazole to the earthworm Aporrectodea icterica [2]. Experiments were conducted in soils presenting various textures and organic carbon contents, spiked with formulated epoxiconazole 7 to 56 days prior to their extraction at one-fold to ten-fold the recommended dose. In parallel, the epoxiconazole concentration was determined in exposed earthworms. All the analysis were performed by UHPLCMS/ MS. The fungicide’s effects were evaluated by measuring weight gain, enzymatic activities and total protein contents. The proposed method to evaluate bioavailability was based on the pesticide entrapment in the cavity of hydroxypropyl-?-cyclodextrin, thus fulfilling the criteria of the ISO 17402 norm [3]. Furthermore, this mild method was demonstrated to be sensitive to soil sorption capacities and to ageing. The mild extraction method was then applied to explore the relationship between total and bioavailable concentrations in soil and in A. icterica, over 7 or 28 days exposure time. This demonstrated the proportionality between epoxiconazole concentration in earthworm and available in soil (up to 96%, with regression coefficient R2 0.98). Sublethal effects on earthworm remained not significant. References 1. C. Pelosi, S. Joimel, D. Makowski, 2013. Chemosphere 90, 895-900 2. S. Nélieu, G. Delarue, E. Ollivier, P. Awad, F. Fraillon, C. Pelosi, Environ. Sci. Pollut. Res. In Press DOI 10.1007/s11356-015-5270-4 3. ISO 17402, 2008. Soil quality - Guidance for the selection and application of methods for the assessment of bioavailability of contaminants in soil and soil materials

Fluoroquinolone antibiotics such as ciprofloxacin can be found in soils receiving exogenous organic matter (EOM). Their long-term behavior in EOM-amended soils and their level of biodegradability are not well understood partly due to a lack of methods to estimate their environmental availability. We performed different aqueous extractions to quantify the available fraction of 14 C-ciprofloxacin in soils amended with a compost of sewage sludge and green wastes or a farmyard manure contaminated at relevant environmental concentrations. After minimizing 14 C-ciprofloxacin losses by adsorption on laboratory vessel tubes, three out of eleven different aqueous solutions were selected, i.e., Borax, Na 2 EDTA and 2-hydroxypropyl-β-cyclodextrin. During 28 d of incubation, the non-extractable fractions were very high in all samples, i.e., 57–67% of the initial 14 C-activity, and the availability of the antibiotic was very low, explaining its low biodegradation. A maximum of 6.3% of the initial 14 C-activity was extracted from soil/compost mixtures with the Na 2 EDTA solution, and 7.2% from soil/manure mixtures with the Borax solution. The available fraction level was stable over the incubation in soil/compost mixtures but slightly varied in soil/manure mixtures following the organic matter decomposition. The choice of different soft extractants highlighted different sorption mechanisms controlling the environmental availability of ciprofloxacin, where the pH and the quality of the applied EOM appeared to be determinant.

Pharmaceuticals can enter the environment when organic waste products are recycled on agricultural soils. The extraction of pharmaceuticals is a challenging step in their analysis. The very different extraction conditions proposed in the literature make the choice of the right method for multi-residue analysis difficult. This study aimed at evaluating, with experimental design methodology, the influence of the nature, pH and composition of the extraction medium on the extraction recovery of 14 pharmaceuticals, including 8 antibiotics, from soil and sewage sludge. Preliminary experimental designs showed that acetonitrile and citrate-phosphate buffer were the best extractants. Then, a response surface design demonstrated that many cross-product and squared terms had significant effects, explaining the shapes of the response surfaces. It also allowed optimising the pharmaceutical recoveries in soil and sludge. The optimal conditions were interpreted considering the ionisation states of the compounds, their solubility in the extraction medium and their interactions with the solid matrix. To perform the analysis, a compromise was made for each matrix. After a QuEChERS purification, the samples were analysed by online SPE-UHPLC-MS-MS. Both methods were simple and economical. They were validated with the accuracy profile methodology for soil and sludge and characterised for another type of soil, digested sludge and composted sludge. Trueness globally ranged between 80 and 120 % recovery, and inter- and intra-day precisions were globally below 20 % relative standard deviation. Various pharmaceuticals were present in environmental samples, with concentration levels ranging from a few micrograms per kilogramme up to thousands of micrograms per kilogramme. Graphical abstract Influence of the extraction medium on the extraction recovery of 14 pharmaceuticals. Influence of the ionisation state, the solubility and the interactions of pharmaceuticals with solid matrix. Analysis of different soils and organic waste products.

Microcystins are the most common cyanotoxins and may be expected wherever blooms of cyanobacteria occur in surface waters. Their persistence both in the irrigation water and in the soil can lead to their transfer and bioaccumulation into agricultural plants. The aim of this work was to investigate microcystin accumulation in Solanum lycopersicum cultivar MicroTom. The plant was exposed to either Microcystis aeruginosa crude extracts containing up to 100 μg eq.MC-LRL(-1) in a soil-plant system for 90 days or pure radiolabeled (14)C-MC-LR in a hydroponic condition for 48 h. Toxin bioaccumulation in the soil and different plant tissues was assessed both by the PP2A inhibition assay and by liquid chromatography-mass spectrometry (LC/MS/MS). After 90 days of exposure, microcystins persisted in the soil and their free extractable concentrations accumulated were very low varying between 1.6 and 3.9 μg eq.MC-LR kg(-1) DW. Free MC-LR was detected only in roots and leaves with concentrations varying between 4.5 and 8.1 μg kg(-1) DW and between 0.29 and 0.55 μg kg(-1) DW, respectively. By using radioactivity ((14)C-MC-LR), the results have reported a growing accumulation of toxins within the organs roots>leaves>stems and allowed them to confirm the absence of MC-LR in fruits after 48 h of exposure. The bioconcentration factor (BCF) was 13.6 in roots, 4.5 in leaves, and 1.4 in stems. On the other hand, the results highlight the presence of two radioactive fractions in different plant tissues. The non-extractable fraction of radioactivity, corresponding to the covalently bound MC-LR, was higher than that of the extractable fraction only in roots and leaves reaching 56% and 71% of the total accumulated toxin, respectively. Therefore, results raise that monitoring programs must monitor the presence of MCs in the irrigation water to avoid the transfer and accumulation of these toxins in crops.

Microcystins (MCs) are cyanobacterial heptapeptides, produced by several genera and species of cyanobacteria, which have been involved in poisoning of animals throughout the world and have also been implicated in human health problems. They are regarded as the most frequently occurring and widespread of the cyanotoxins, with more than 100 MC variants reported to date including the present study. The lake des Oiseaux is a shallow permanent freshwater lake located in north-eastern Algeria. It is an important natural reserve playing a major role for the migratory birds after the crossing of the Mediterranean Sea and from the Sahara desert. In recent years, possibly related to increased eutrophication of the lake, massive blooms of cyanobacteria identified as Microcystis spp. have been observed. A bloom sample collected in September 2013 was analyzed by the serine/threonine phosphatase PP2A inhibition assay and liquid chromatography-mass spectrometry to determine respectively, the total concentration of MCs and the different variants of these toxins present. The results revealed that the Microcystis spp. bloom sample contained microcystins of which 21 putatively congeners were detected. Among these, 12 known microcystins (MC-RR, MC-LR, MC-FR, MC-WR, MC-YR, MC-LA, MC-(H4)YR, MC-HilR, [Asp(3)]MC-RAba, and [Glu(OCH3)(6)]MC-LR) and two new congeners ([Asp(3)]MC-HarAba and [Glu(OCH3)(6)]MC-FR) were characterized, considering their molecular mass and the fragment ions produced by collision-induced dissociation of the [M+H](+) ions. MC-RR was the major (43.4%) in the bloom sample.

International audience; This study aims in analyzing, at laboratory scale, the mechanisms and performances of 2,4,6-Trinitrotoluene (TNT) removal from contaminated water using electro-Fenton process. This treatment belongs to the group of advanced oxidation processes (AOPs), regarded as the most effective approach to decontaminate wastewater from persistent and toxic organic pollutants. In this study, the TNT degradation was investigated through high resolution LC–ESI–MS/MS to tentatively identify the aromatic by-products. The proposed degradation scheme shows a complex alternation of oxidation and reduction mechanisms, evidencing the importance of the electrochemical reduction in the whole process. Furthermore, oxidative opening of the highly reduced/oxidized TNT aromatic ring occurred rapidly during the treatment, leading to the transient accumulation of short chain carboxylic acids such as malonic, glyoxylic, oxalic and formic acids. Mineralization occurred but was delayed in front of TNT and carboxylic acids, showing the persistence of some recalcitrant by-products

The nitrate-induced photodegradation of phenylureas in water was demonstrated to occur efficiently using natural sunlight irradiation. The kinetics of disappearance was found to be dependent on the inducer and substrate concentrations, the phenylurea structure and the origin and composition of the aqueous matrix including the presence of nitrite. The measured effects under sunlight were of the same order of those measured previously in the lab using our solar light simulated system. However, by-product distribution might differ substantially particularly considering the nitration pathway.

Avec nos remerciements à Jodie Thénard, Virginie Grondin, Jean-Pierre Pétraud, Amélie Trouvé, Christelle Marrauld et Françoise Poiroux; Earthworms play a key role in agroecosystem soil processes. This study aims to assess the effects of different doses of a commercial formulation of epoxiconazole (Opus®), a persistent and widely used fungicide, on the earthworm Aporrectodea icterica. A laboratory study was conducted in a natural soil in order to measure effects of Opus® on earthworm mortality, uptake, weight gain, enzymatic activities (catalase and glutathione-S-transferase), and energy resources (lipids and glycogens). The estimated LC50 was 45.5 mg kg−1, or 268 times the recommended dose. Weight gains were 28, 19, and 13 % of the initial weight after 28 days of exposure in the control and D1 and D10 (1 and 10 times the recommended dose) treatments, respectively. No difference was observed for catalase activity between the three treatments, at 7, 14, or 28 days. The glutathion-S-transferase (GST) activity was two times as high in D1 as in D0 at 14 days. At 28 days, glycogen concentration was lower in D10 than in the D1 treatment. This study highlighted moderate sublethal effects of the commercial formulation Opus® for earthworms. Considering that these effects were observed on a species found in cultivated fields, even at recommended rates, much more attention should be paid to this pesticide.

Microcystins are cyclic heptapeptides hepatotoxins produced by aquatic cyanobacteria such as Microcystis aeruginosa. The wide occurrence of toxic microcystins in freshwater is a threat to water quality and health of living organisms. Here, we irrigated an agricultural soil daily with a cyanobacterial extract diluted at environmental concentrations of microcystin–leucine–arginine, from 0.005 to 0.1 mg equivalent MC-LR L−1, for 90 days. We analyzed the impact on the growth and physiology of tomato, Solanum lycopersicum cultivar MicroTom. Our results show a stimulation of the tomato plant development, in terms of inflorescence and blooming, after exposure to the lowest concentration, of 0.005 mg eq. MC-LR L−1, during the 40 first days post-germination. That effect was not apparently associated with physiological disturbances of the tomato plants.

A new analytical procedure is proposed for monitoring nicosulfuron (sulfonylurea herbicide) in aquatic mesocosms derived from complex ecosystems. The approach is based on alternate use of the anionic and molecular forms of the pesticide during the procedure. It also takes into account the sensitivity of the molecule to hydrolysis. The procedure involves solid-phase extraction on a polystyrene-divinylbenzene support followed by a conventional high-performance liquid chromatographic analysis with UV-diode array detection. Recovery tests on samples from natural waters demonstrated that the performances obtained were convenient for monitoring aquatic mesocosms (recoveries of 91+/-12% at 0.5 microg L(-1)). The method was used to monitor nicosulfuron in mesocosms initially spiked at 2 or 30 microg L(-1) . The evolution curves were compared to those obtained from mesocosms contaminated with atrazine at the same initial doses. The sensitivity of phytoplankton communities to nicosulfuron in aquatic mesocosms was found to be very limited.

The degradation of the pesticide metsulfuron methyl induced by excitation of iron(III) aqua complexes was studied at 365 nm. The process involved the formation of hydroxyl radicals and was shown to depend on Fe(OH)(2+) concentration. The second order rate constant of the reaction of metsulfuron methyl and hydroxyl radical was evaluated by laser flash photolysis experiments to k = 3.5 x 10(9) mol(-1) L s(-1). Various products were formed. Among them 2-amino-4-methoxy-6-methyl-1,3,5-triazine, 2-(carbomethoxy) benzenesulfonamide and hydroxylated derivatives represent the major photoproducts. Compounds arising from the cleavage of the triazine moiety were also found. After prolonged irradiation, a total disappearance of metsulfuron methyl and a complete mineralization of the solution were obtained.

The degradation of mono- and dichlorophenylureas under ozone/hydrogen peroxide conditions was investigated in order to establish the effect of the structural parameters. The N-dimethyl phenylureas (mono- and dichloro) appear to differ strongly from the corresponding N-methyl N-methoxy analogues in terms of disappearance of the parent pesticide and evolution of the by-products identified by MS and MS-MS. The degradation rate of the latter is slower by a factor of 2.5 giving rise to additional pathways (hydroxylation of the phenyl ring and carbinolamine intermediate). Experiments with 14C-labelled compounds allow a complete determination of the mass balances obtained after solid-phase-extraction (SPE). This study demonstrates the interest of SPE for reaction monitoring and compares the performances of different types of phases for this purpose used alone or in combination. Mineralisation is also evaluated regarding 14CO2 production and found to contribute up to 20% in the degradation process.

The direct determination of pesticides adsorbed on solid-phase extraction (SPE) membranes by matrix-assisted laser desorption/ionization (MALDI) combined with quadrupole ion trap mass spectrometry is reported. Ionization was carried out in an external source followed by injection of desorbed ions into the trap using an ion lens. Ion accumulation from multiple desorption events and tandem mass spectrometric procedures were used to enhance the sensitivity and selectivity of the analysis. The potential of the method for quantitative analysis is discussed.

Laser desorption Fourier transform ion cyclotron resonance mass spectrometry was coupled with solid-phase extraction (SPE) on C18 silica membranes for the determination of selected pesticides in water. The desorption process for hydroxyatrazine was demonstrated to take place at the surface of the membrane. The method was further investigated using other model compounds, flumequine, isoproturon and flutriafol. These three pesticides have shown a different behaviour to hydroxyatrazine when extracted on SPE membranes. Among them, only flumequine was detected at 248 nm. The use of a 355 nm laser wavelength allowed the detection of all three compounds but under more vigorous conditions leading to significant fragmentation. The unexpected behaviour at 248 nm is not clearly explained by the respective UV absorptions of the molecules at the laser wavelength but would more likely depend on different interactions with the membrane.

Despite constraining legislation and increasing efficiency of pesticides (with a decrease in the applied amounts), their use still cause a contamination of environment (air, soil and water). To conciliate agricultural and environmental interests, a better understanding of the fate of pesticides is needed, in particular because it will determine the exposure and consequently the impact of pesticides on the target and non-target organisms. This goal requires new efforts of research at different scales (from molecular to field scale). Following application, most of the pesticides reach the soil either after direct application or after foliage wash-off. As a major interface between other environmental compartments, the soil plays a preponderant buffering role in the fate of pesticides. Apart volatilization, the main processes that control the fate of pesticides in soils are retention on soil particles and degradation (biotic and abiotic). These coupled bio-physico-chemical processes can lead to a transitory or permanent accumulation of pesticides in soils or, on the contrary, to their elimination from the environment. They determine the pesticide concentration in the soil solution, and have a large influence on pesticide transfer toward ground or surface waters and on their ecotoxicological impacts on soil organisms as well. The main difficulties in studying and predicting the retention and degradation of pesticides in soils are the diversity of chemical structures and reactivities of pesticides, the high diversity of soils and their heterogeneous composition and structure. In addition, the pedoclimatic conditions, in particular soil temperature and water content, have a strong influence on retention and degradation because of their effect on soil biological, chemical and physical properties. Therefore, the objective of this chapter is to provide an overview of the factors involved in the retention and degradation of pesticides in soils and to discuss and clarify the needs of new integrated approach. In particular, this work will examine (i) the pertinent scales (among elementary constituents, aggregates and mesoscopic scales) for both retention and degradation studies, (ii) the integrative properties that should be considered, such as hydrophobicity of the organo-clay granulometric fraction or soil structure, and (iii) the primordial role of water.

International audience; The removal of TNT from contaminated water can be achieved through advanced oxidation treatment. In the present study, its degradation by Fenton reaction was investigated at laboratory scale. Degradation efficiencies were compared by varying Fenton's reagents concentration and ratios. The parallel monitoring of Fenton's reagents concentrations allowed evidencing hydrogen peroxide or ferrous ion contents as limiting factors for TNT removal. The absolute rate constant of the reaction between TNT and hydroxyl radicals was also determined. TNT by-products corresponding to early stage degradation were identified by LC-ESI-MS and LC-ESI-MS/MS after solid phase pre-concentration. For the first time, formation of 2,4,6-trinitro-cyclohexa-2,4-dienol (uncommon), 2,4,6-trinitrobenzylalcohol, 2,4,6-trinitrobenzaldehyde, and one of the dinitro-hydroxy-benzaldehyde isomers were evidenced. Degradation pathways involving hydroxyl radical attacks resulting in methyl group oxidation, decarboxylation, aromatic ring breakage and hydrolysis, were finally proposed. (C) 2011 Elsevier B.V. All rights reserved.

International audience; The ecotoxicological impact of nitrate-induced photodegradation products of diuron and chlorotoluron was studied through monospecific biotests conducted in conjunction with experiments in outdoor aquatic mesocosms. Organisms representing three trophic levels were used: two heterotrophic microorganisms, the luminescent bacterium Vibrio fischeri and the ciliated protozoa Tetrahymena pyriformis, and one metazoa, the gastropod Lymnaea stagnalis. Among the variety of the phenylurea photoproducts, the N-formylated ones appeared clearly more toxic than the parent compounds towards the microorganisms, whereas the nitroderivatives showed a similar toxicity. Using photodegraded solutions of diuron, toxicity was maintained or even increased during disappearance of the initial herbicide, demonstrating that some of the photoproducts may have an impact additively or in synergy. Enzymatic biomarker assays performed on Lymnaea stagnalis exposed under monospecific conditions showed significant effects, due to the combination of nitrate with the pesticide and its photoproducts. A positive impact on snail fecundity was observed with chlorotoluron both under monospecific laboratory and integrated mesocosm conditions. Oviposition stimulation took place when first- and second-generation photoproducts were predominant.

International audience; The nitrate and nitrite-induced phototransformation of monuron in aqueous solution has been investigated using 300–450 nm light irradiation. The degradation kinetics was estimated under various conditions of concentrations of substrate and inducer, oxygen content and pH. From the numerous photoproducts identified using LC–ESI-MS–MS and their evolution curves a degradation scheme was proposed. Besides oxidation of the N-terminus group (major pathway in the presence of NO3−) and a minor contribution of direct photolysis, the other photoproducts originated from Cl/OH substitution, regiospecific hydroxylation and/or nitration of the phenyl ring. The two last processes occurred competitively under the NO3− conditions even at “environmental” concentrations of the inducer yielding significant levels of nitro-derivatives. Their production was found to be oxygen-dependent in contrast to the NO2− conditions.

International audience; Two alternatives for the rapid simultaneous quantification of six sulfonylurea herbicides and five of their main degradation products in natural water are proposed. For concentration, the compounds were extracted on a polystyrene-divinylbenzene solid phase under pH and elution conditions that suppressed any hydrolysis. The eluates were analysed by liquid chromatography coupled to electrospray tandem mass spectrometry within 20 min. The whole method was validated and shown to give no hydrolysis artefacts. The application of off-line and on-line SPE of sulfonylureas enabled the 0.1 mu g L-1 and 1 ng L-1 LOQ levels to be reached, respectively. The on-line SPE-LC-MS-MS method allowed the accurate quantitation of all sulfonylureas and three degradation products at 0.1 mu g L-1 or below in natural water, with an average repeatability of 8%.

International audience; The photo-induced degradation of diuron (3-(3,4-dichlorophenyl)-1,1-dimethylurea) in aqueous solution under simulated solar irradiation has been investigated in the presence of Nitrite/Nitrate ions. The degradation rates were compared by varying environmental parameters including substrate and inducer concentrations, oxygen content and pH. The photoproducts were identified by extensive LC–ESI–MS and LC–ESI–MS–MS studies after SPE preconcentration on prepacked cartridges. In both Nitrate and Nitrite conditions, oxidation of the N-(CH3)2 terminus group is the main process leading to the N-monodemethylated (NHCH3), N-formyl (N(CH3)CHO) and the uncommon and unstable carbinolamine (N(CH3)CH2OH) by-products. Cl/OH substituted and nitrated phenylureas are formed minorily. Degradation pathways involving OHradical dot and dimer radicals as reactive species are proposed.

The photocatalytic degradation of the antimicrobial triclosan (5-chloro-2-(2,4-dichlorophenoxy)phenol) was studied using different types of TiO2 suspension photocatalysts (Degussa P25, PC50 and PC 500) and excitation wavelength of 365 nm. In all cases, the degradation process mainly involved the formation of hydroxyl radicals. Under our experimental conditions and in aerated solutions, the irradiation in the presence of TiO2 P25 permitted the evaluation of the half-lifetime to about 10 min. The intermediate byproducts were identified by means of HPLC/MS/MS using electrospray (ES) interfacing technique. They were obtained as a result of three main primary processes: (i) homolytic scission of C O bond leading to the formation of 2,4-dichlorophenol and chlorocatechol, (ii) hydroxylation of the phenolic group and (iii) dechlorination process leading to the formation of 5-chloro-2-(4-chlorophenoxyl)phenol. Under prolonged irradiation efficient mineralisation of triclosan solution was observed as evidenced by means of total organic carbon (TOC) evolution as well as chloride anions formation as a function of irradiation time.

Here we evidenced the photo-induced degradation of monolinuron, a phenylurea herbicide, through the 300–450 nm light excitation of nitrite and nitrate species. The degradation pathways were compared to those obtained under direct photolysis at 254 nm. When using NO3 − and NO2 − as photoinducers, hydroxyphenyl-substituted photodegradation products were found to be formed specifically through the involvement of OH° radicals. NO− and NO2-phenyl substituted compounds were also observed as a result of the production of NO° and NO2° radicals. Half-lives of monolinuron in aqueous solutions were measured in various conditions of concentrations of substrate and inducer, oxygen content and pH.

The preconcentration of aqueous solutions containing atrazine degradation products was investigated using solid-phase extraction on octadecyl and cation-exchanger silica phases. The retention and elution steps were studied and evaluated separately in order to define and optimize the critical experimental parameters involved. A strategy which combines sequentially both phases is proposed to fractionate compounds into two groups of increasing polarities: firstly, the native pesticide, hydroxyatrazine and most chlorotriazines on octadecyl support, and secondly monodealkylated hydroxytriazines, ammeline and ammelide on cation-exchanger. This tandem procedure was successfully applied for analysing and quantifying atrazine ozonation products and its efficiency demonstrated using [U-ring 14C]-labelled atrazine experiments.

The aqueous ozone treatment of atrazine [2-chloro-4-(ethylamino)-6-(isopropylamino)-s-triazine] in the presence of hydrogen peroxide was reinvestigated using a new tandem solid-phase extraction procedure which includes a C18 reverse phase support and a strong cation exchanger. In this way, both chlorotriazines and the more polar hydroxytriazines could be analyzed to establish total molar balances of degradation products vs the initial pesticide in the 45−55% range. In all the experimental conditions examined (treatment rates, pH, and eventual presence of carbonates), ammeline (2,4-diamino-6-hydroxy-s-triazine) was found as the major end-product (20% at pH 8). 2-Chloro-4,6-diamino-s-triazine was produced competitively, and the ratio between both products was dependent on the hydroxyl radical content. A number of new intermediates were identified i.e. amino-aldehydes and a carbinolamine. The carbinolamine functionality is of great interest since being involved in the dealkylation process of the triazinic am...

Studies on atrazine ozonation performed in methanol containing solutions showed a strong influence of the methanol content which might favour direct O3 reactions as compared to processes induced by OH radicals. The importance of the slackening effect on the degradation rate of atrazine (which demonstrates a scavenger activity) was evaluated in various solvent compositions and pseudo-kinetic constants k' were found to be in the 10−3-10−2 s−1 range. The appearence rate of deethylatrazine as major oxidation product was thus also modified (k' values between 10−4 and 10−3 s−1). Several by-products were detected which are either related to deethylatrazine (intermediates or oxidation products) or belong to competitive pathways. Among them, a number of formamides (a new class of atrazine ozonation products) were identified using MS and MS-MS techniques. These compounds are produced by oxidation of the N-ethylamino group likely through a non radicalar process. Deschloro-triazines were also characterized a...

Until the present, analysis of aqueous solutions of atrazine has been conducted using a combination of liquid chromatography or gas chromatography with mass spectrometry, after a preconcentration step. We explore herein a new approach for studying support-phase-extracted atrazine and hydroxyatrazine samples. Solid-phase extraction membranes are inserted directly into the cell of a Fourier-transform mass spectrometer for analysis after laser ionization. It appears that atrazine and its metabolite have very different ionization processes. In the case of hydroxyatrazine, the [M + H]+ ion signal can be correlated to the concentration of the extracted solution. These encouraging results might open the route to a quantification method.

The ability of liquid chromatography combined with positive-ion low-collision-energy tandem mass spectrometry for screening and characterization of atrazine metabolites in aqueous solutions is examined. The strategy used was defined after investigations on the structure and origin of the main daughter ions through experiments done by desorption chemical ionization with NH3 or ND3 as reagent gas. Following this, a three-step procedure was proposed which included parent-ion spectra based on [XCNC(NH)NH2]+ (with X Cl or OH) ions apparently formed via ion-dipole complexes and found to be highly diagnostic for chlorotriazines and hydroxytriazines respectively.