Activated carbon (AC) amendment has been shown to reduce bioavailability of hydrophobic contaminants in the bioactive layer of sediment. Unwanted secondary effects of AC amendment could be particularly undesirable for ecologically important seagrass meadows, but so far, only a few studies have been conducted on effects on submerged plants. The purpose of this study was to investigate effects on growth and cover of submerged macrophytes in situ after AC amendment. Test sites were established within a seagrass meadow in the severely contaminated Norwegian fjord Gunneklevfjorden. Here we show that AC amendment does not influence neither cover nor length of plants. Our study might indicate a positive effect on growth from AC in powdered form. Hence, our findings are in support of AC amendment as a low-impact sediment remediation technique within seagrass meadows. However, we recommend further studies in situ on the effects of AC on submerged vegetation and biota. Factors influencing seasonal and annual variation in plant species composition, growth and cover should be taken into consideration. | An In Situ Experimental Study of Effects on Submerged Vegetation After Activated Carbon Amendment of Legacy Contaminated Sediments | acceptedVersion

peer reviewed | A study on Trace Elements (TE) from sea urchin gonads has been conducted in the western Mediterranean Sea. Contamination data were used to determine a Trace Method Pollution Index (TEPI). TE concentrations varied considerably depending on the location of the sampling stations. The results showed that five trace elements (Zn, Fe, As, Al, Cu) are ubiquitous. The geographical area considered (Corsica) represents an important range of environmental conditions and types of pressure that can be found in the western Mediterranean Sea. TEPI was used to classify the studied sites according to their degree of contamination and allowed reliable comparison of TE contamination between local and international sites. TE contamination of the western Mediterranean Seadisplayed a north-to-south gradient, from the Italian coasts down through the insular Corsican coasts to the north African littoral. Due to the increasing environmental pressure on the Mediterranean Sea, a regular monitoring of TE levels in marine organisms is necessary to prevent any further environmental deterioration.

Embargo until 30 July 2019 | Activated carbon (AC) amendment has been shown to reduce bioavailability of hydrophobic contaminants in the bioactive layer of sediment. Unwanted secondary effects of AC amendment could be particularly undesirable for ecologically important seagrass meadows, but so far, only a few studies have been conducted on effects on submerged plants. The purpose of this study was to investigate effects on growth and cover of submerged macrophytes in situ after AC amendment. Test sites were established within a seagrass meadow in the severely contaminated Norwegian fjord Gunneklevfjorden. Here we show that AC amendment does not influence neither cover nor length of plants. Our study might indicate a positive effect on growth from AC in powdered form. Hence, our findings are in support of AC amendment as a low-impact sediment remediation technique within seagrass meadows. However, we recommend further studies in situ on the effects of AC on submerged vegetation and biota. Factors influencing seasonal and annual variation in plant species composition, growth and cover should be taken into consideration. | acceptedVersion

[Departement_IRSTEA]Ecotechnologies [TR1_IRSTEA]TED [ADD1_IRSTEA]Valoriser les effluents et déchets organiques | International audience | There are 20 full-scale Phosclean® filters for P removal being used together with treatment wetlands (TW) to treat wastewaters of small and medium-size communities, in France. Some of them are in operation for more than five years now, reason why some field experiences are being conducted under the project name of APPROVE (APatite for P Removal and Valorisation: an Evaluation) to assess the current performance and saturation conditions of full-scale filters. This paper will present fieldfeedback results from 4 different wastewater treatment plants (WWTP) with Phosclean® filters. WWTP A (filter A) has been monitored since its commission in 2017 to assess the effluent's pH evolution due to material dissolution in the very first stage of its life span. Three other WWTPs (B, C and D) with hydraulically different Phosclean® filters, in operation since 2012, are also monitored: vertical up-flow (filter B); vertical down-flow (filter C) and horizontal flow (filter D). Assessment of the treatment plants use regulatory surveys since the beginning of plants operations. As treatment plants have not the same capacity, the number of regulatory surveys is heterogeneous and not high enough to have a precise knowledge on saturation levels and retention kinetics. Consequently, additional measurement campaigns have been carried out over two years. Four-day campaigns have been carried out twice per year for each WWTP. In order to evaluate the P retention's performance, 24h-flow proportional samplings at the inlet and outlet of the Phosclean® filter were coupled to spotsamplings at different hydraulic retention times inside the filter to measure retention's kinetic. Online P-PO4 measurements at the outlet of the filter were also conducted to observe possible dynamic within a day. Mayor parameters as pH, conductivity, redox potential, TSS, BOD, COD, N, TP, P-PO4 3- as well as anions and cations were measured for these samples. For filter A, a flowmeter and an online pH probe at the outlet of the filter have been implemented for several months. To determine the nature of phosphate precipitates, SEM and DRX analyses were performed for solid samples taken at different points in the filters. Furthermore, fluorescein-tracer tests were carried out to precisely determine water retention times and possible short-circuiting, as well as dynamic penetrometer measurements to assess potential changes on the material density due to surface precipitation. Results of first campaigns show that P concentration at the outlet of filters C and D respect the maximal regulation limit for total phosphorous disposal after 5 years of operation. This is not the case for filter B, after 4 years of operation, which is over the regulation limit fixed at 2.5mgTP/L. Nevertheless, differences in the regulation limits, inlet P concentrations, hydraulic loads, operation and design, must be taken into consideration to analyze variations of filters performances. The evolution of TP concentrations along time will be presented for all filters according to saturation levels for comparison. Kinetics evolution as a function of saturation conditions will be also presented. Results show that filters B, C and D are at different saturation levels, being filter B the most saturated.

International audience | Both macroplastic and microplastic contamination levels were assessed for the first time in a tropical river estuary system, i.e. the Saigon River, that traverses a developing South East Asian megacity, i.e. Ho Chi Minh City, Vietnam. The analysis of floating debris collected daily on the Nhieu Loc - Thi Nghe canal by the municipal waste management service shows that the plastic mass percentage represents 11-43%, and the land-based plastic debris entering the river was estimated from 0.96 to 19.91 g inhabitant-1d-1, namely 350 to 7270 g inhabitant-1yr-1. Microplastics were assessed in the Saigon River and in four urban canals by sampling bulk water for anthropogenic fiber analysis and 300 μm mesh size plankton net exposition for fragment analysis. Fibers and fragments are highly concentrated in this system, respectively 172,000 to 519,000 items m-3and 10 to 223 items m-3. They were found in various colors and shapes with smallest size and surface classes being predominant. The macroplastics and fragments were mainly made of polyethylene and polypropylene while the anthropogenic fibers were mainly made of polyester. The relation between macroplastic and microplastic concentrations, waste management, population density and water treatment are further discussed.

International audience | Both elevated O3 and fertilization can significantly reduced NH3 stomatal compensation point (χs) of poplar clone '546', and fertilization can mitigate the negative effects of O3 on χs.

A combined approach merging stable isotopes and fatty acids was applied to study anthropogenic pollution in the Río Negro estuary. Fatty acid markers of vegetal detritus indicated considerable allochthonous inputs at freshwater sites. Correlative evidence of diatom fatty acids, δ13C, chlorophyll and particulate organic matter suggested the importance of diatoms for the autochthonous organic matter production at the river mouth. Low δ15N values (~0�) and high fatty acid 18:1(n-7) concentrations in the suspended particulate matter, in combination with the peaks of coliforms and ammonium, indicated a strong impact of untreated sewage discharge. The 15N depletion was related to oxygen-limited ammonification processes and incorporation of 15N depleted ammonium to microorganisms. This work demonstrates that the combined use of lipid and isotopic markers can greatly increase our understanding of biogeochemical factors and pollutants influencing estuaries, and our findings highlight the urgent need for water management actions to reduce eutrophication.

Author's accepted version (postprint). | This is an Accepted Manuscript of an article published by Springer in Water, Air and Soil Pollution on 27/10/2018. | Available online: https://link.springer.com/article/10.1007/s11270-018-4013-9 | acceptedVersion