Comportement géochimique des herbicides et de leurs produits de dégradation en milieu estuarien et marin côtier

The presence and geochemical behaviour of herbicides were investigated in estuarine and marine waters of the French coasts (Seine, Charente, Gironde estuaries and Rhône delta). These organic contaminants were quantified by capillary Gas Chromatography (GC) using Nitrogen-Phosphorus Detecter and identified by GCIMS (Mass Spectrometry). A liquid-solid extraction method using XAD-2 resins was developed,  allowing the analysis of both chloro-triazines and their degradation products in the nanogram per litre (ng.l-1) detection range. Different types of chemicals were identified in the estuarine and coastal waters: triazine, amide and acetanilide herbicides. These compounds are mainly present in the water phase, with less than 1% associated with particulate matter. Simazine, atrazine and de-ethylatrazine (DEA), one of the degradation products of atrazine, were detected at ali sampling sites and during ali seasons. The concentration levels of herbicides depend on location, season and type of compounds. The concentrations of simazine, atrazine and DEA in the fluvial zone ranged between 21-299 ng.l-1, 35-591 ng.l-1 and 23-110 ng.l-1 respectively, and between 5-63 ng.l-1 , 4-70 ng.l-1 and 5-19 ng.l-1 in high salinity waters (S>30). The dissolved herbicides behave conservatively during estuarine mixing. Gross riverine fluxes of pesticides transported by rivers into the estuaries are similar to net fluxes exported to the sea. Gross fluxes of dissolved atrazine vary between 0.12 kg.d-1 in the Charente estuary and 25.1 kg.d-1 in the Gironde estuary, and between 0.11 and 7.4 kg.d-1 for DEA in the Charente estuary and Rhône delta respectively.La présence et le comportement géochimique de composés herbicides ont été déterminés dans les eaux estuariennes et marines côtières des trois façades maritimes françaises (Seine, Charente, Gironde, Rhône). Les composés ont été quantifiés par Chromatographie en Phase Gazeuse (CPG) couplée à un détecteur sélectif vis-à-vis des atomes d'azote et de phosphore (NPD), et confirmés par CPG/SM (Spectrométrie de Masse). Une méthode d'Extraction Liquide-Solide (ELS) sur résines XAD-2 a été mise au point, permettant l'analyse conjointe des produits de dégradation des chloro-triazines et des composés parents à des concentrations voisines du ng.t-1 . Les composés majoritairement identifiés appartiennent aux familles des triazines, amides et acétanilides. Ils sont présents essentiellement en phase dissoute : la part des composés associée aux particules est inférieure à 1%. La présence ubiquiste et pérenne de deux herbicides appartenant à la famille des chloro-triazines (simazine et atrazine) est mise en évidence, de même que celle d'un des produits de dégradation de l'atrazine, la dé-éthylatrazine (DEA). Les niveaux de concentration en herbicides diffèrent selon les sites, les périodes de l'année et les composés étudiés. En zone fluviale, les concentrations en simazine, atrazine et DEA sont comprises entre 21 et 299 ng.l-1, entre 35 et 591 ng.l-1, et entre 23 et 110 ng.l-1 respectivement. Dans les eaux de salinité supérieure à 30, elles varient entre 5 et 63 ng.l-1 (simazine), 4 et 70 ng.l-1 (atrazine), et 5 et 19 ng.l-1 (DEA). La dilution des composés dans les eaux estuariennes s'effectue de façon conservative : les flux bruts journaliers en herbicides entrant dans l'estuaire sont équivalents aux flux nets exportés vers les eaux marines côtières. Ils sont compris entre 0.12 kg.j-1 (Charente) et 25.1 kg.j-1 (Gironde) pour l'atrazine, et entre 0.11 kg.j-1 (Charente) et 7.4 kg.j-1 (Rhône) pour la  DEA

Perfluoroalkyl substances (PFASs) in the marine environment: Spatial distribution and temporal profile shifts in shellfish from French coasts

Perfluoroalkyl substances (PFASs) were investigated in filter-feeding shellfish collected from 2013 to 2017 along the English Channel, Atlantic and Mediterranean coasts of France. PFOS (perfluorooctane sulfonate), PFTrDA (perfluorotridecanoic acid), PFTeDA (perfluorotetradecanoic acid), PFDoDA (perfluorododecanoic acid) and PFUnDA (perfluoroundecanoic acid) were detected in more than 80% of samples, thus indicating widespread contamination of the French coastal environment by these chemicals. The distribution of PFAS concentrations showed differences according to sampling locations and years. PFOS was the predominant PFAS in most samples collected from English Channel and Atlantic coasts until 2014, but the opposite was observed in 2015, 2016 and 2017, while perfluoroalkyl carboxylic acids (PFCAs) prevailed in Mediterranean samples in all study years. Among PFCAs, PFTrDA showed the highest maximum (1.36 ng g−1 ww) and median (0.077 ng g−1 ww) concentrations in 2016–2017. Other PFAS median concentrations were within the 0.014 (PFNA) - 0.055 (PFTeDA) ng g−1 ww range. The profiles determined each year in most Mediterranean samples suggest distinctive sources. PFOS median concentrations showed a significant decrease over the study years, from 0.118 to 0.126 ng g−1 ww in 2013–2015 to 0.066 ng g−1 ww in 2016 and 2017. ∑PFCAs showed no trends in concentration ranges over the same years. The shift in PFAS profiles from PFOS to long-chain PFCAs over the study period reflects PFOS production phase-out, combined with continuous inputs of PFCAs into the marine environment. These results provide reference data for future studies of the occurrence of contaminants of emerging concern on European coasts

Levels and trends of the emerging contaminants HBCDs (hexabromocyclododecanes) and PFCs (perfluorinated compounds) in marine shellfish along French coasts

The levels and congener patterns of HBCDs (hexabromocyclododecanes) and PFCs (perfluorinated compounds) were determined in filter-feeding molluscs collected in 2008 and 2010 along the coasts of mainland France. alpha-HBCD and PFOS (perfluorooctane sulfonate) were detected in all samples, revealing widespread contamination of the coastal environment by these emerging contaminants. The spatial distribution of Sigma-HBCD concentrations showed higher median levels in samples from the Mediterranean Sea and English Channel respectively, i.e. 0.19 ng g(-1) wet weight (ww) and 0.08 ng g(-1) ww, related to high anthropogenic pressure from urban and industrial activities, while the median concentration was 0.05 ng g(-1) ww in samples from the Atlantic coast. Among PFCs, PFOS was the only compound detected in all samples and PFDA (perfluorodecanoic acid) was the second most frequently-detected compound. PFOS median concentrations were 0.18 ng g(-1) ww, 0.09 ng g(-1) ww and 0.04 ng g(-1) ww in samples from the English Channel, the Atlantic coast and the Mediterranean coast respectively. The highest PFOS concentration was found in the Loire estuary, possibly related to local industrial activities. The Mediterranean samples showed a different pattern, with predominant long-chain PFCAs (perfluorocarboxylic acids), suggesting the presence of alternative sources on the Mediterranean coast. The temporal trends studied in archived samples from the Seine estuary site showed a significant exponential increase in HBCD concentrations between 1981 and 2011, with a doubling time of 7 years, while PFOS levels underwent a significant linear decrease over time. These trends are coherent with current regulations on the use of these compounds. The results presented in this paper provide the first data on the contamination of the French coastal marine environment by the selected emerging compounds, and constitute a reference for the future monitoring of French coastal contamination by emerging contaminants

High levels of halogenated natural products in large pelagic fish from the Western Indian Ocean

Concentrations, profiles and muscle-liver distribution of halogenated natural products (HNPs) and anthropogenic persistent organic pollutants (POPs) were investigated in five large pelagic fish species and one smaller planktivore fish species from the Western Indian Ocean. Analysis of swordfish muscle from the Seychelles revealed the predominance of HNPs, with the highest concentrations found for 2′-methoxy-2,3′,4,5′- tetraBDE (2′-MeO-BDE 68 or BC-2), 6-methoxy-2,2′,4,4′- tetraBDE (6-MeO-BDE 47 or BC-3) and 2,3,3′,4,4′,5,5′-heptachloro-1′-methyl-1,2′-bipyrrole (Q1), along with varied contributions of further HNPs. The mean concentration of ∑HNPs (330 ng/g lw) was one or two orders of magnitude higher than ∑DDTs (60 ng/g lw) and ∑PCBs (6.8 ng/g lw). HNPs (BC-2, BC-3 and Q1) were also predominant in individual samples of three tropical tuna species from the Seychelles and from other regions of the Western Indian Ocean (Mozambique Channel, off Somalia and Chagos Archipelago). Non-targeted gas chromatography coupled with electron capture negative ion mass spectrometry operated in the selected ion monitoring mode (GC/ECNI-MS-SIM) analysis of one swordfish sample indicated low abundance of rarely reported HNPs (three hexachloro-1′-methyl-1,2′-bipyrrole (Cl6-MBP) isomers and pentabromo-1,1′-dimethyl-2,2′-bipyrroles (Br5-DBP)) but no further abundant unscreened polyhalogenated compounds

Levels and trends of synthetic musks in marine bivalves from French coastal areas

The levels and trends of four bioaccumulative synthetic musks (galaxolide - HHCB, tonalide - AHTN, musk xylene - MX and musk ketone - MK) were investigated in filter-feeding bivalves collected yearly since 2010 at sites of contrasted pressure along the French coasts. Quantification rates were high for all 4 compounds (85-99%), indicating their geographical and temporal extensive occurrence in the French coastal environment. The polycyclic musks HHCB and AHTN prevailed, with median concentrations of 2.27 ng g-1 dw and of 0.724 ng g-1 dw, whilst nitromusks were found 1 to 2 orders of magnitude lower. These levels were in the high range of those encountered for various other CEC families at the same sites and comparable to those from other locations on European coasts. Unlike for the other musks, the accumulation of HHCB was evidenced to be species-specific, with significantly lower levels found in oysters in comparison with mussels, possibly suggesting a higher metabolization in oysters. Geographical differences in musk distribution highlighted the sites under strong anthropogenic pressures and these differences were found to be consistent between years. The HHCB/AHTN ratio proved to be discriminant to explain the relative occurrence of polycyclic musks. The 8-year time series showed that only the now-banned compound MX displayed a significant decrease in most sites, whilst stable concentrations of the other musks suggested consistency in their usage over the last decade. These results provide reference data for future studies of the occurrence of personal care products on European coasts

Per- and Polyfluoroalkyl Substances (PFASs)

60 pages, 5 figures, 4 tablesPer- and polyfluoroalkyl substances (PFASs) are anthropogenic contaminants of emerging concern that are ubiquitous in the marine environment. This chapter provides recent insights into the main aspects of research on this class of compounds in the oceans. It describes their main uses and predominant sources in the marine environment and provides an update on the analytical procedures fit for marine matrices. Occurrence and processes affecting these compounds in abiotic compartments are addressed, followed by a focus on bioaccumulation and biomagnification in biota. The biological effects in marine organisms are then reviewed per taxa. In agreement with recent literature, recommendations for future research are proposed, which should guide future efforts toward the key environmental questions on PFASsPeer reviewe

Bahariya. Pratiques funéraires et lieux de culte

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Cracked and shucked: GC-APCI-IMS-HRMS facilitates identification of unknown halogenated organic chemicals in French marine bivalves

High resolution mass spectrometry (HRMS)-based non-target analysis coupled with ion mobility spectrometry (IMS) is gaining momentum due to its ability to provide complementary information which can be useful in the identification of unknown organic chemicals in support of efforts in unraveling the complexity of the chemical exposome. The chemical exposome in the marine environment, though not as well studied as its freshwater counterparts, is not foreign to chemical diversity specially when it comes to potentially bioaccumulative and bioactive polyhalogenated organic contaminants and natural products. In this work we present in detail how we utilized IMS-HRMS coupled with gas chromatographic separation and atmospheric pressure chemical ionization (APCI) to annotate polyhalogenated organic chemicals in French bivalves collected from 25 sites along the French coasts. We describe how we used open cheminformatic tools to exploit isotopologue patterns, isotope ratios, Kendrick mass defect (Cl scale), and collisional cross section (CCS), in order to annotate 157 halogenated features (level 1: 54, level 2: 47, level 3: 50, and level 4: 6). Grouping the features into 11 compound classes was facilitated by a KMD vs CCS plot which showed co-clustering of potentially structurally-related compounds. The features were semi-quantified to gain insight into the distribution of these halogenated features along the French coast, ultimately allowing us to differentiate between sites that are more anthropologically impacted versus sites that are potentially biodiverse