Erratum to: Neurobehavioral deficits and brain oxidative stress induced by chronic low exposure of persistent organic pollutants mixture in adult female rat

International audience

[Departement_IRSTEA]Ecotechnologies [TR1_IRSTEA]TED | International audience | Areas similar to free water surface constructed wetlands (FWS CWs) placed between wastewater treatment plants and receiving water bodies, under the perception that they increase water quality. More than 500 systems are in operation with a multitude of configurations and intended outcomes. In order to monitor these areas, research is being carried out to understand the fate of water and conventional pollutants in these systems. To this aim, a FWS CW located in southern France is monitored with traditional grab samples and 24-h flow composite samples. This site has also been instrumented with 6 Ion-Selective Electrodes (ISEs) probes recording continuously ammonium and nitrate concentrations. Because pollutant concentrations are usually low in treated wastewater, sometimes close to quantification limits of laboratory methods, we are developing appropriate methodologies for the management of the probes and the data processing. In this context, we propose a reliable methodology to increase the quality of data from ISE probes. This methodology is based on (i) laboratory experiments for sensor characterization and (ii) field tests. Laboratory experiments allowed characterizing the operating parameters like response time, linearity range, quantification limits, and interferences. Furthermore, for one-year, field tests are led every two weeks to (i) evaluate the required cleaning frequency and (ii) do grab samples analyses that help to validate data from the 6 ISEs. A drift in time appears to be significant for ammonium sensor. An additional experiment is currently monitoring this drift to correct this effect on measurement. This study has confirmed that it is fundamental to understand the technical limitations of the measuring equipment and set appropriate maintenance and calibration methodologies in order to have an accurate interpretation of data. The result is an operating protocol mainly concerning an acceptable cleaning frequency of two weeks, a stronger complementary calibration method using water from the experimental site, an evaluation of the drift and the determination of quantification limits of these ISEs (1 mg/L for ammonium and 0.5 m/L for nitrate). This protocol generates validated data that can be used to study nitrate and ammonium dynamics. In combination with the usual 24-h composite sampling method, it gives a good understanding of the fate of nitrogen within this FWS CW system. An example of data processing will be submitted.

International audience | Medicago sativa was cultivated at a former harbor facility near Bordeaux (France) to phytomanage a soil contaminated by trace elements (TE) and polycyclic aromatic hydrocarbons (PAH). In parallel, a biotest with Phaseolus vulgaris was carried out on potted soils from 18 sub-sites to assess their phytotoxicity. Total soil TE and PAH concentrations, TE concentrations in the soil pore water, the foliar ionome of M. sativa (at the end of the first growth season) and of Populus nigra growing in situ, the root and shoot biomass and the foliar ionome of P. vulgaris were determined. Despite high total soil TE, soluble TE concentrations were generally low, mainly due to alkaline soil pH (7.8–8.6). Shoot dry weight (DW) yield and foliar ionome of P. vulgaris did not reflect the soil contamination, but its root DW yield decreased at highest soil TE and/or PAH concentrations. Foliar ionomes of M. sativa and P. nigra growing in situ were generally similar to the ones at uncontaminated sites. M. sativa contributed to bioavailable TE stripping by shoot removal (in g ha−1 harvest−1): As 0.9, Cd 0.3, Cr 0.4, Cu 16.1, Ni 2.6, Pb 4, and Zn 134. After 1 year, 72 plant species were identified in the plant community across three subsets: (I) plant community developed on bare soil sowed with M. sativa; (II) plant community developed in unharvested plots dominated by grasses; and (III) plant community developed on unsowed bare soil. The shoot DW yield (in mg ha−1 harvest−1) varied from 1.1 (subset I) to 6.9 (subset II). For subset III, the specific richness was the lowest in plots with the highest phytotoxicity for P. vulgaris.

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.

International audience | The insecticide chlordecone applied for decades in banana plantations currently contaminates 20,000 ha of arable land in the French West Indies. Although the impact of various pesticides on soil microorganisms has been studied, chlordecone toxicity to the soil microbial community has never been assessed. We investigated in two different soils (sandy loam and silty loam) exposed to different concentrations of CLD (D0, control; D1 and D10, 1 and 10 times the agronomical dose) over different periods of time (3, 7, and 32 days): (i) the fate of chlordecone by measuring C-14-chlordecone mass balance and (ii) the impact of chlordecone on microbial community structure, abundance, and function, using standardized methods (-A-RISA, taxon-specific quantitative PCR (qPCR), and C-14-compounds mineralizing activity). Mineralization of C-14-chlordecone was inferior below 1 % of initial C-14-activity. Less than 2 % of C-14-activity was retrieved from the water-soluble fraction, while most of it remained in the organic-solvent-extractable fraction (75 % of initial C-14-activity). Only 23 % of the remaining C-14-activity was measured in nonextractable fraction. The fate of chlordecone significantly differed between the two soils. The soluble and nonextractable fractions were significantly higher in sandy loam soil than in silty loam soil. All the measured microbiological parameters allowed discriminating statistically the two soils and showed a variation over time. The genetic structure of the bacterial community remained insensitive to chlordecone exposure in silty loam soil. In response to chlordecone exposure, the abundance of Gram-negative bacterial groups (beta-, gamma-Proteobacteria, Planctomycetes, and Bacteroidetes) was significantly modified only in sandy loam soil. The mineralization of C-14-sodium acetate and C-14-2,4-d was insensitive to chlordecone exposure in silty loam soil. However, mineralization of C-14-sodium acetate was significantly reduced in soil microcosms of sandy loam soil exposed to chlordecone as compared to the control (D0). These data show that chlordecone exposure induced changes in microbial community taxonomic composition and function in one of the two soils, suggesting microbial toxicity of this organochlorine.

[Departement_IRSTEA]Ecotechnologies [TR1_IRSTEA]TED | International audience | This simulation study investigates the treatment performance of a French style single stage vertical flow constructed wetland using a zeolite layer in order to increase ammonia removal. For the modelling exercise, the CW"2D biokinetic model of the HYDRUS Wetland Module is used. The calibrated model is able to determine the effect of different depths of the zeolite layer on ammonia removal in order to optimize the design of the system. For calibration of the model, hydraulic effluent flow rates as well as influent and effluent concentrations of COD and NH4-N have been measured. To model the adsorption capacity of zeolite, Freundlich isotherms are used. The results present the simulated treatment performance within three different depths of the zeolite layer, 10 cm (default), 15 cm and 20 cm respectively. The increase of the zeolite layer depth leads to a decrease of the simulated NH4-N effluent concentration.

[Departement_IRSTEA]Ecotechnologies [TR1_IRSTEA]TED | International audience | The classic design of French constructed wetlands (CW) consists in two successive stages of vertical flow filters (VFFs). While this configuration permits full nitrification, it also needs a large surface area (> 2 m²/pe). Therefore high ammonium removal efficiencies are of interest for compact systems such as single stage CW.The use of zeolite as filtrating medium could fix the problem thanks to itsexchange capacity and its high affinity for ammonium. Indeed, the ammonium is adsorbed during the feeding cycle then nitrified during the rest period.This study aims to assess the feasibility of ammonium removal by zeolite in a first stage VFF fed with raw sewage. Seven columns (40 cm-depth, 107 cm²) filled with zeolite under a gravel layer and one control without zeolitewere studied over four months. All columns, except a zeolite-control, were packed with inoculated media froma treatment plant. The columns have been operated in a sequential mode of feeding and rest periods of 3.5d and 7d, respectively, with synthetic solution of ammonium (100mgNH4-N/L). Two columns were fed with different concentrations of ammonium while two others were also fed sodium in order to assess the impact of the ammonium concentration and the presence of competitive species, respectively. The nitrogen concentrations (ammonium, nitrite and nitrate) were measured at the inlet and the outlet.