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[Departement_IRSTEA]Ecotechnologies [TR1_IRSTEA]TED [Axe_IRSTEA]TED-EPURE | International audience | This paper presents the key elements that emerged from a 3-year study on 4 campsites. Each of them has its own Vertical-Flow Constructed Wetlands (VFCW) for on-site wastewater treatment. Each year, the pollution discharge peaked in the 5 to 6-week summer period but was zero for a 6-month period. The natural-concentrate wastewater is collected into a short sewer network. Hydraulic load and campground occupancy rate were tightly correlated. The effluent has a characteristically high nitrogen concentration due to the lower greywater-producing activity. These quantitative and qualitative elements were used to define the camper equivalent' as a daily pollutant load of about 100 L water, 90 gCOD, 35 gBOD5, 40 gSS, 11 gKN and 1.4 gPt. During the 5-6 weeks of peak visitor traffic, the full first stage receives an organic load of 200 gCOD.m-2.d-1 and 25 gKN.m-2.d-1, which is 2 to 3.5-fold higher than the loads conventionally applied in VFCW systems in France. Despite these heavy loads, COD removal remains constant (at 91%) over the season. During the summer peak, nitrification drops sharply but KN removal rate holds steady near 60%. This study demonstrates that VFCWs can robustly handle massive load increases. The paper concludes that total system size can be downscaled to 0.75 m²/camper. This design allows to reach minimum yields of 75% KN, provided that the system is built and run to state-of-the-art rules. | Cet article présente les éléments clés issus d'une étude de 3 ans sur 4 campings qui traitent leurs eaux usées de manière individuelle par des Filtres Plantés de Roseaux à écoulement vertical (FPRV) aux dimensionnements différents. La charge hydraulique et le taux d'occupation du camping sont étroitement corrélés. L'émission est nulle 6 mois par an et la pointe estivale dure 5 à 6 semaines. Les eaux usées, collectées par un réseau court sont naturellement concentrées. L'effluent présente notamment une très forte concentration en azote du fait d'une activité ménagère réduite. Ces éléments qualitatifs et quantitatifs permettent de définir l' « équivalent campeur » par une charge de pollution journalière d'environ 100 L d'eau, 90 g de DCO, 35 g de DBO5, 40 g de MES, 11 g de NK et 1,4 g de Pt. Au cours des 5-6 semaines de fréquentation maximale, la totalité du 1er étage reçoit une charge organique d'environ 200 gDCO.m-².j-1 et 25 gNK.m-².j-1, soit 2 à 3,5 fois plus que les charges classiques appliquées en FPRV en France. En dépit de ces fortes charges, l'élimination de la DCO reste constante (91 %) au cours de la saison. Lors du pic de fréquentation estival, la nitrification décroît fortement mais le rendement global se maintient à environ 60 %. La robustesse des FPRV face à une augmentation massive des charges appliquées est démontrée. L'article conclut par un dimensionnement réduit de 0.75 m2/campeur au total. Ce dimensionnement permet d'atteindre un rendement minimum de 75 % du NK, correspondant à la nitrification, sous réserve que les règles de l'art de construction et d'exploitation soient strictement respectées.

Accumulation of free microcystins (MCs) in freshwater gastropods has been demonstrated but accumulation of MCs covalently bound to tissues has never been considered so far. Here, we follow the accumulation of total (free and bound) MCs in Lymnaea stagnalis exposed to i) dissolved MC-LR (33 and 100 μg L−1) and ii) Planktothrix agardhii suspensions producing 5 and 33 μg MC-LR equivalents L−1 over a 5-week period, and after a 3-week depuration period. Snails exposed to dissolved MC-LR accumulated up to 0.26 μg total MCs g−1 dry weight (DW), with no detection of bound MCs. Snails exposed to MCs producing P. agardhii accumulated up to 69.9 μg total MCs g−1 DW, of which from 17.7 to 66.7% were bound. After depuration, up to 15.3 μg g−1 DW of bound MCs were detected in snails previously exposed to toxic cyanobacteria, representing a potential source of MCs transfer through the food web. The study concerns accumulation and elimination of both free and bound microcystins (MCs) in tissues of a gastropod exposed to MCs producing cyanobacteria or dissolved MC-LR.

Current European Union regulation regarding polychlorinated dibenzo-p-dioxins, polychlorinated dibenzofurans (PCDD/Fs) and dioxin-like polychlorinated biphenyls (dl-PCBs) in food and feed is based on Toxic Equivalent Quotient (TEQ) concept. For confirmatory purpose, the isotope-dilution method associated to a measurement by gas chromatography coupled with high resolution mass spectrometry is usually the method of choice for precisely measuring the 29 target congeners in three separated fractions. Time and cost related to these analyses are very significant. Various kinds of screening concepts can be considered. In the present study, we elaborated and validated a prediction model for the 2005 World Health Organization TEQ in fish, based on the measurement of 4 PCDD/F and 2 non-ortho dl-PCB congeners, potentially analyzable in a single extracted fraction by gas chromatography coupled with mass spectrometry. Large independent datasets have been used for model elaboration (n = 108) and validation (n = 363, n = 357 and n = 6). This study describes a statistical regression model approach for screening PCDD/Fs and dl-PCBs in fish.

Contaminated sediments in the St. Lawrence River remain a difficult problem despite decreases in emissions. Here, sediment and pore water phases were analyzed for total mercury (THg) and methyl mercury (MeHg) and diffusion from the sediment to the overlying water was 17.5 ± 10.6 SE ng cm−2 yr−1 for THg and 3.8 ± 1.7 SE ng cm−2 yr−1 for MeHg. These fluxes were very small when compared to the particle-bound mercury flux accumulating in the sediment (183 ± 30 SE ng cm−2 yr−1). Studies have reported that fish from the westernmost site have higher Hg concentrations than fish collected from the other two sites of the Cornwall Area of Concern, which could not be explained by differences in the Hg flux or THg concentrations in sediments, but the highest concentrations of sediment MeHg, and the greatest proportions of MeHg to THg in both sediment and pore water were observed where fish had highest MeHg concentrations.

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.

We performed a trace analytical study covering nine hormonally active UV-filters by LC–MS/MS and GC–MS in river water and biota. Water was analysed at 10 sites above and below wastewater treatment plants in the river Glatt using polar organic chemical integrative samplers (POCIS). Four UV-filters occurred in the following order of decreasing concentrations; benzophenone-4 (BP-4) > benzophenone-3 (BP-3) > 3-(4-methyl)benzylidene-camphor (4-MBC) > 2-ethyl-hexyl-4-trimethoxycinnamate (EHMC). BP-4 ranged from 0.27 to 24.0 μg/POCIS, BP-3, 4-MBC and EHMC up to 0.1 μg/POCIS. Wastewater was the most important source. Levels decreased with higher river water flow. No significant in-stream removal occurred. BP-3, 4-MBC and EHMC were between 6 and 68 ng/L in river water. EHMC was accumulated in biota. In all 48 macroinvertebrate and fish samples from six rivers lipid-weighted EHMC occurred up to 337 ng/g, and up to 701 ng/g in 5 cormorants, suggesting food-chain accumulation. UV-filters are found to be ubiquitous in aquatic systems.

The spatial distribution of organochlorine pesticides (OCs) in soils and their potential for soil–air exchange was examined. The most prominent OCs were the DDTs (Geometric Mean, GM = 1.6 ng g−1), endosulfans (0.16 ng g−1), and toxaphenes (0.64 ng g−1). DDTs in soils of southern Mexico showed fresher signatures with higher FDDTe = p,p′-DDT/(p,p′-DDT + p,p′-DDE) and more racemic o,p′-DDT, while the signatures in the central and northern part of Mexico were more indicative of aged residues. Soil–air fugacity fractions showed that some soils are net recipients of DDTs from the atmosphere, while other soils are net sources. Toxaphene profiles in soils and air showed depletion of Parlar 39 and 42 which suggests that soil is the source to the atmosphere. Endosulfan was undergoing net deposition at most sites as it is a currently used pesticide. Other OCs showed wide variability in fugacity, suggesting a mix of net deposition and volatilization. Chemical profiles of residues and soil–air fugacities are used to assess the potential of soil as a source of organochlorine pesticides to the air of Mexico.

To better understand interaction mechanisms of pine needles with persistent organic pollutants, single-solute and bi-solute sorption of phenanthrene and pyrene onto isolated cuticular fractions of pine needle were investigated. The structures of cuticular fractions were characterized by elemental analysis, Fourier transform infrared spectroscopy and solid-state 13C NMR. Polymeric lipids (cutin and cutan) exhibited notably higher sorption capabilities than the soluble lipids (waxes), while cellulose showed little affinity with sorbates. With the coexistence of the amorphous cellulose, the sorption of cutan (aromatic core) was completely inhibited, so the cutin components (nonpolar aliphatic moieties) dominated the sorption of bulk needle cuticle. By the consumption of the amorphous cellulose under acid hydrolysis, sorption capacities of the de-sugared fractions were dramatically enhanced, which controlled by the exposed aromatic cores and the aliphatic moieties. Furthermore, the de-sugared fractions demonstrated nonlinear and competitive sorption due to the specific interaction between aromatic cores and polycyclic aromatic hydrocarbon.