3D coupled modeling approach is used for the PCB dispersion assessment in the Gulf of Lion and its transfer to zooplankton via biogeochemical processes. PCB budgets and fluxes between the different species of PCB: dissolved, particulate, biosorbed on plankton, assimilated by zooplankton, which are governed by different processes: adsorption/desorption, bacteria and plankton mortality, zooplankton excretion, grazing, mineralization, volatilization have been estimated. Model outputs were compared with the available in situ data. It was found that the Rhone River outflows play an important role in the organism contamination in the coastal zone, whereas the atmospheric depositions are rather more important in the offshore zones. The transfer of the available contaminant to bacteria and phytoplankton species is mainly related to the biomass present in the water column. Absorption fluxes (grazing) to zooplankton are rather higher than the passive sorption fluxes, which are themselves also linked to the sorption coefficient.

Livret Guide | Depuis l'adoption de la Directive Cadre sur l'Eau (DCE) en 2000 les autorités portent une attention accrue envers les contaminations de l'eau par les pesticides. Les autorités en charge de la question ont alors conçu de nombreux instruments d'action publique visant à les réduire. Néanmoins, la situation est toujours très préoccupante aujourd'hui. Selon le service de la donnée et des études statistiques (SDES), les pesticides sont présents en France dans la plupart des cours d'eau et des eaux souterraines. Ainsi, bon nombre de masses d'eau n'ont pas atteint l'objectif de "bon état" en 2015, au regard des indicateurs fixés par la DCE. Pour appuyer l'action publique, de nombreux projets de recherche ont été engagés afin de concevoir de nouveaux outils et méthodes de gestion des pollutions mais aussi produire des références (études de cas, analyse partagée, norme technique, etc.). Il existe un grand nombre d'outils développés dans le cadre de travaux de recherche pouvant apporter un appui aux institutions impliquées dans la protection des ressources en eau vis-à-vis des pesticides. Ils ne sont pas souvent connus ou accessibles que dans un cercle restreint d'initiés. Afin d'offrir une vue d'ensemble, ainsi que d'informer et de guider les utilisateurs potentiels, un référentiel a été établi à partir de l'inventaire des outils, méthodes et dispositifs de production de références existants ou en cours de développement.

The work presented here aims at comparing monitoring of S-metolachlor, the major pesticide in use in the Arcachon Bay (South West of France, transitional coastal area), by chemical analysis (monthly passive sampling) and contaminant dissipation modeling from sources (Mars-2D model). The global strategy consisted in i) identifying the major sources of S-metolachlor to the Bay, ii) monitoring these sources for 12 months, and iii) comparing modeled data in the Bay based on measured inputs, to chemical measurements made inside the Bay along with the 12-month source monitoring. Results first showed that the major S-metolachlor surface inputs to the Arcachon Bay are mainly from one single source. Modeled and measured data were in good agreement at 5 sites in the Bay, both in terms of concentration range and seasonal trends. Modeling thus offers a cost-effective solution for monitoring contaminants in transitional waters, overcoming in addition the technical limitations for measuring pg L−1 or lower levels in coastal waters. However, we highlighted that secondary sources may affect accuracy at local level.

Concentrations of 6 trace metals (Ag, Cd, Cu, Ni, Pb, Zn) in the muscle of 2 sharks (Galeus melastomus and Scyliorhinus canicula), 4 teleosts (Helicolenus dactylopterus, Lepidorhombus boscii, Micromesistius poutassou and Phycis blennoides) and 1 crustacean (Nephrops norvegicus) were compared between the Bay of Biscay (Atlantic Ocean) and the Gulf of Lions (Mediterranean Sea). Although average concentrations and the trace element pollution index were generally higher in the Gulf of Lions, significant differences between the two ecosystems were only found for Zn for Helicolenus dactylopterus, and for Ag and Cu for the crustacean N. norvegicus. Moreover, some relationships between trophic level or size and metal concentrations were found for these two species. The absence of clear pattern may result from the blurring effect of contamination and excretion that may act differentially for all species and all elements.

Entanglement of marine fauna is one of the principal impacts of marine litter, with an incidence that can vary strongly according to regions, the type and the quantity of marine litter. On the seafloor, areas dominated by sessile suspension feeders, such as tropical coral reefs or deep-sea coral and sponge aggregations, have been termed “animal forests” and have a strong potential to monitor the temporal and spatial trends of entanglement by marine litter, especially fishing gears. Several characteristics of these organisms represent advantages while avoiding constraints and bias. Biological constraints and logistical aspects, including tools, are discussed to better define a strategy for supporting long-term evaluation of accumulation and entanglement of marine litter.

Microplastics (<5 mm) exhibit intrinsic features such as density, hydrophobic surface, or high surface/volume ratio, that are known to promote microbial colonization and biofilm formation in marine ecosystems. Yet, a relatively low number of studies have investigated the nature of microplastic associated bacterial communities in coastal ecosystems and the potential factors influencing their composition and structure. Here, we characterized microplastics collected in the Bay of Brest by manual sorting followed by Raman spectroscopy and studied their associated bacterial assemblages using 16S amplicon high-throughput sequencing. Our methodology allowed discriminating polymer type (polyethylene, polypropylene and polystyrene) within small size ranges (0.3–1 vs. 1–2 vs. 2–5 mm) of microplastics collected. Data showed high species richness and diversity on microplastics compared to surrounding seawater samples encompassing both free living and particle attached bacteria. Even though a high proportion of operational taxonomic units (OTU; 94 ± 4%) was shared among all plastic polymers, polystyrene fragments exhibited distinct bacterial assemblages as compared to polyethylene and polypropylene samples. No effect of microplastic size was revealed regardless of polymer type, site and date of collection. The Vibrio genus was commonly detected in the microplastic fraction and specific PCR were performed to determine the presence of potentially pathogenic Vibrio strains (namely V. aestuarianus and the V. splendidus polyphyletic group). V. splendidus related species harboring putative oyster pathogens were detected on most microplastic pools (77%) emphasizing the need of further research to understand the role of microplastics on pathogen population transport and ultimate disease emergence.

In the marine environment, most bivalve species base their reproduction on external fertilization. Hence, gametes and young stages face many threats, including exposure to plastic wastes which represent more than 80% of the debris in the oceans. Recently, evidence has been produced on the presence of nanoplastics in oceans, thus motivating new studies of their impacts on marine life. Because no information is available about their environmental concentrations, we performed dose-response exposure experiments with polystyrene particles to assess the extent of micro/nanoplastic toxicity. Effects of polystyrene with different sizes and functionalization (plain 2-μm, 500-nm and 50-nm; COOH-50 nm and NH2-50 nm) were assessed on three key reproductive steps (fertilization, embryogenesis and metamorphosis) of Pacific oysters (Crassostrea gigas). Nanoplastics induced a significant decrease in fertilization success and in embryo-larval development with numerous malformations up to total developmental arrest. The NH2-50 beads had the strongest toxicity to both gametes (EC50 = 4.9 μg/mL) and embryos (EC50 = 0.15 μg/mL), showing functionalization-dependent toxicity. No effects of plain microplastics were recorded. These results highlight that exposures to nanoplastics may have deleterious effects on planktonic stages of oysters, presumably interacting with biological membranes and causing cyto/genotoxicity with potentially drastic consequences for their reproductive success.

Biogeochemical parameters of pore waters, including dissolved organic matter, nutrients, sulfate, alkalinity, and chloride are explored as convenient and sensitive proxies to monitor the CO2 geological storage sites. Five sites for a CO2 storage project in the Pohang Basin of the East Sea in South Korea were investigated for the pre-injection biogeochemical conditions of these sites. Higher dissolved organic carbon (~36 mg L−1), chromophoric and fluorescent dissolved organic matter, nutrients, and alkalinity were observed in a fluvially affected acoustic blanking site with geological faults. A general increasing downcore trend of measured DOM parameters, nutrients, and alkalinity with depth was found at the acoustic blanking site affected by riverine runoff with significant correlations among the parameters (R2: ~0.4–0.8), highlighting the impact of geological features and external inputs on the downcore biogeochemical properties. The results presented in this study suggest that DOM could be utilized as a robust and complementary biogeochemical parameter.

The surface sediments (0–4cm, n=6) from Chabahar Bay were analyzed to assess the concentrations, composition, and potential eco-hazards of associated PAHs. The range of ∑16 PAHs' concentration was 25.75–312.38ngg−1 dw, with mean and median levels of 126.7 and 55.12ngg−1 dw, respectively. The bay was classified as a region with low to moderate PAH pollution. The sources of PAHs varied, and 2–3-ring compounds were dominant (37–90%). There was no significant correlation between TOC/grain size and levels of PAHs. Total carcinogenic PAHs ranged from 0.21 to 79.68ngg−1 dw, and benzo(a)pyrene was the main constituent of calculated toxic equivalencies. The bay sediments were rarely hazardous and could not address narcotic hazards for the benthic community. Biota-sediment accumulation was not predicted for the examined coral Acropora valida. In equilibrium conditions, release of ∑16PAHs from the bay sediments was estimated to be 0.536μgL−1 at its maximum.

A total of 43 surface sediment collected from rivers and the estuaries in the Pearl River Delta (PRD) region and Mirs Bay from the South China were analyzed for twelve halogenated flame retardants (HFRs) including polybrominated diphenyl ethers (PBDEs) using liquid chromatography-tandem mass spectrometer system. Their levels, spacial distribution, congener profiles and possible sources were investigated. Decabromodiphenyl ethane (DBDPE) was the predominant contaminant (1.520–1714ng/g dw) in the study area exceeding those of PBDEs (8.090–595.8ng/g dw), implying that DBDPE has been the predominant HFR products in this region in recent years in addition to PBDEs. Whereas the ratio of [DBDPE/BDE 209] varied among samples, this is indicative of different usage patterns of HFRs between PRD region and Mirs Bay. The PBDEs congener was dominated by BDE 209, with the average value accounting for 86.8% of the total PBDE in the sediment samples.