Water monitoring of emerging pesticides in France : Organization of a screening study from prioritization to measurements
The Water Framework Directive (WFD) has set up a European list of 41 Priority Substances (PS) which have to be regularly monitored in European waters. Moreover, it requires Member States to establish national lists of substances to be monitored at river basin level. Despite these provisions, it is widely recognised by the scientific community that several substances of emerging concern are currently overlooked and as a result they are not adequately monitored by national authorities. As part of the implementation of the National Action Plan on Micropollutants in the Aquatic Environment (October 2010), the French Ministry of Ecology decided to implement an innovative and comprehensive approach to improve national monitoring programmes under the WFD. This includes the setting-up of a watch list of substances to be investigated at the national level in order to acquire missing information about the level of exposure of emerging contaminants in the aquatic environment and allow regular updating of the list of River Basin-Specific Pollutants to be regularly monitored. Concurrently, an Action Plan on Drug Residues in Water, co-led by the Ministries of Ecology and Public Health, was published in May 2011. This action plan supports prioritisation of pharmaceuticals for which screening studies are needed in view of the implementation of emission reduction measures.
(02/09/2013)
INERIS, EPOC, EPHE, PSL, UB, INSU - CNRS, CNRS, ISA, UCBL, INC-CNRS, CNRS, LPTC, UB, CNRS
Export of 13C-depleted dissolved inorganic carbon from a tidal forest bordering the Amazon estuary
Tidal wetlands play a significant role in the coastal carbon cycle and exchange material with the atmosphere and coastal ocean. Here, we report on changes in dissolved inorganic carbon speciation and isotopic composition throughout a 24 h cycle (2 tidal cycles) in Feb. 2007 in a channel connecting the Amazon estuary to the basin of a tidal forest. At this site, tropical forest soils are inundated at high tide by estuarine freshwater, and temporal concentration changes in the channel reflect exchanges between the forest and estuary. Our data show an export of dissolved inorganic carbon (DIC) in the form of excess CO2 and, to a much lesser extent, CH4. However, the tidal forest traps suspended sediments. Mixing plots of DIC versus conductivity showed that the DIC originated from the tidal forest soil, with a negligible contribution from the local watershed. Evolution of the isotopic signature of DIC reveals a 13C-depleted source (-56.9 ± 3.3‰), presumably originating from a dominant methanogenic pathway of carbon mineralization followed by almost complete CH4 oxidation in the organic clay-rich freshwater soil.
(Estuarine, Coastal and Shelf Science. vol. 129, n° 0272-7714, pp. 23-27, 01/09/2013)
EPOC, EPHE, PSL, UB, INSU - CNRS, CNRS, GET, IRD, UT3, Comue de Toulouse, INSU - CNRS, CNES, CNRS, LOG, INSU - CNRS, ULCO, CNRS, IRD [Ile-de-France], ULCO, BOREA, MNHN, IRD, UPMC, CNRS
Semi-automatic analysis and interpretation of sediment profile images
Sediment Profile Images (SPIs) are widely used for benthic ecological quality assessment under various environmental stressors. The processing of the information contained in SPIs is slow and its interpretation is largely operator dependent. We report here on a new software: SpiArcBase, which allows for a semi-automatic analysis of SPIs and facilitates the interpretation of observed features. SpiArcBase enhances the objectivity of the information extracted from SPIs, especially for the assessment of the apparent Redox Potential Discontinuity (aRPD). This new software also allows the user to create and manage a database containing original SPIs and corresponding derived pieces of information. Examples of the use of SpiArcBase for SPIs collected during a case study carried out within the Rhône River Prodelta are provided. Correlations between: (1) visually and automatically assessed aRPD and Benthic Habitat Quality Index (BHQ), and (2) automatically assessed aRPD and BHQ and surface sediment organic carbon support the use of this new software.
(Environmental Modelling and Software. vol. 47, n° 1364-8152, pp. 42-54, 01/09/2013)
EPOC, EPHE, PSL, UB, INSU - CNRS, CNRS
Polychlorinated biphenyls (PCBs) and Polybrominated Diphenyl Ethers (PBDEs) in surface sediments from Monastir Bay (Tunisia, Central Mediterranean): Occurrence, distribution and seasonal variations
(Chemosphere. vol. 93, n° 0045-6535, pp. 487-493, 01/09/2013)
ECOSEAS, CNRS, UniCA, INSTM, EPOC, EPHE, PSL, UB, INSU - CNRS, CNRS, USO
Isturitz, Oxocelhaya and Erberua Caves (Pyrénées-Atlantiques, France): geoarchaeological studies
Isturitz, Oxocelhaya and Erberua Caves are located in the foothills of the western Pyrenees. The landscape is hilly and is crossed by a wide valley with a small river, the Arberoue. Downstream, the river disappears into the limestone of Gaztelu Hill: this underground flow created the Erberua Cave. Above this natural tunnel we observe three fossil staged caves: Oxocelhaya, Isturitz and Rocafort. The Gaztelu Caves provide a major European Prehistoric archaeological site. The first recorded data came from the Isturitz Cave (1895), then from the Oxocelhaya Cave (1929) and finally from the Erberua Cave (1973) giving evidence of human occupation during the Mid-Upper Palaeolithic period. These archaeological remains are not uniformly distributed. In Erberua, some of the paintings suggest a Gravettian use of the cave but the works date from the Magdalenian time (Middle and/or Upper). In Oxocelhaya Cave, the settlement may date from Aurignacian time but the art works generally date from the Magdalenian time. In Isturitz Cave, the importance and diversity of the Aurignacian objects are exceptional and prove the permanent nature of this settlement where numerous activities took place. Also during the Gravettian time, an enormous quantity of material is proof of a very important human presence. During the Middle Magdalenian time, the activities are marked in particular by hundreds of portable art, this is why this cave has been described as one of the most important aggregation sites of the Pyrenees. The research team is multidisciplinary and was established in 2011 around twelve main objectives. Our contribution concerns the first two stages and includes speleologists, geologists and karstologists. The first stage was the charting of the numerous listed activities and the second stage will analyze their organization according to the topographic, geological and karstologic specificities of the Gaztelu Hill.
(27/08/2013)
TRACES, EHESS, UT2J, Comue de Toulouse, MCC, Inrap, CNRS, GET, IRD, UT3, Comue de Toulouse, INSU - CNRS, CNES, CNRS, EPOC, EPHE, PSL, UB, INSU - CNRS, CNRS, ADES, UBM, CNRS, Inrap, LEMTA, UL, CNRS
Record of historical mercury trends in sediments from the Laguna del Plata, Córdoba, Argentina
(25/08/2013)
UB, EPOC, EPHE, PSL, UB, INSU - CNRS, CNRS, SPE, CNRS, Bordeaux INP, UBM
Development of a larval bioassay using the calanoid copepod, Eurytemora affinis to assess the toxicity of sediment-bound pollutants
(Ecotoxicology and Environmental Safety. vol. 94, n° 0147-6513, pp. 60 - 66, 01/08/2013)
LEMA, ULH, NU, EPOC, EPHE, PSL, UB, INSU - CNRS, CNRS, M2C, UNICAEN, NU, INSU - CNRS, UNIROUEN, NU, CNRS
Equatorial Pacific peak in biological production regulated by nutrient and upwelling during the late Pliocene/early Pleistocene cooling
The largest increase in export production in the eastern Pacific of the last 5.3 Myr (million years) occurred between 2.2 and 1.6 Myr, a time of major climatic and oceanographic reorganization in the region. Here, we investigate the causes of this event using reconstructions of export production, nutrient supply and oceanic conditions across the Pliocene-Pleistocene in the eastern equatorial Pacific (EEP) for the last 3.2 Myr. Our results indicate that the export production peak corresponds to a cold interval marked by high nutrient supply relative to consumption, as revealed by the low bulk sedimentary 15N/14N (δ15N) and alkenone-derived sea surface temperature (SST) values. This ∼0.6 million year long episode of enhanced delivery of nutrients to the surface of the EEP was predominantly initiated through the upwelling of nutrient-enriched water sourced in high latitudes. In addition, this phenomenon was likely promoted by the regional intensification of upwelling in response to the development of intense Walker and Hadley atmospheric circulations. Increased nutrient consumption in the polar oceans and enhanced denitrification in the equatorial regions restrained nutrient supply and availability and terminated the high export production event.
(Biogeosciences. vol. 10, n° 1726-4170, pp. 5663-5670, 01/08/2013)
LOCEAN, IPSL, ENS-PSL, PSL, UVSQ, UPMC, CEA, INSU - CNRS, X, IP Paris, CNES, CNRS, MNHN, IRD, UPMC, INSU - CNRS, CNRS, URI, EPOC, EPHE, PSL, UB, INSU - CNRS, CNRS, CAU
Iron and sulfur biogeochemical processes involved in mercury mobility and speciation in an artificial aquifer
Although many data are available on the Hg cycle in terrestrial surface aquatic environments, little is known on its behaviour in subsurface and deep aquifers where environmental conditions (anoxia, water saturation) may be favourable to Hg methylation. Bioavailability of Hg, a prerequisite for its methylation by sulphate or iron reducing bacteria, is mainly controlled by physico-chemical conditions and the strong affinity of Hg for organic matter or iron (oxy)hydroxides. This work presents an original experimental setup combining geochemical and microbiological approaches in order to imitate reactions observed in aquifers (i.e., Hg biosorption, solubilisation versus sequestration, speciation, dual effect of iron and sulphate). Two columns were filled in the lower half with sterile sand and in the upper half with a sterile mixture of sand and iron oxides, initially enriched with Hg(II). The water flow was ascendant. Five septa set regularly along the columns enabled water sampling from the different layers of the column without perturbing water flow or in-situ experimental conditions. After an abiotic rinsing period, the system was inoculated with a bacterial consortium and physico-chemical and microbial parameters were monitored in time and space. The inflowing groundwater was supplemented with sulphate (370 g.L-1 MgSO42-) and lactate (830 mg.L-1 sodium lactate) to encourage sulphate-reducing bacteria in the first column (A) and with molybdate (0.40 mmol.L-1) to inhibit sulphate reduction and glucose (10 g.L-1) to favour iron-reducing bacteria in the second column (B). At the end of the experiment (130 days), microbial methylation potentials were evaluated using stable isotope-spiked incubations, diversity using Denaturing Gel Gradient Electrophoresis (DGGE) followed by band sequencing and Fluorescent in situ hybridisation (FISH). Raman spectrometry was carried out to identify neo-mineral formation and selective extractions provided information on Hg distribution between the solid carrier phases. In column A microbial activity assessed by substrate consumption began after 15 days and induced a progressive decrease in the sulphate concentrations at the column outlet and the visual observation of black FeS precipitates (identified as partially oxidized makinawite). When sulphate reduction peaked after 120 days, iron was leached from the column as well as monomethylmercury (MMHg) and Hg. Bacterial diversity did not vary significantly either in time or space, sulphate reducing bacteria were observed with FISH and a sequenced DNA band bore resemblance to Desulfotomaculum reducens. In column B bacterial activity directly induced iron reduction (measured in the outlet as Fe(II)) as well as Hg leaching and MMHg formation. Shewanella sp. was observed with FISH. In both columns methylation potentials averaged 1% and selective extractions showed a shift of Hg from the ferrihydrite towards the organic matrix and newly formed FeS. These results contribute to understanding the interactions between bacteria and geochemical mechanisms controlling Hg fate and behaviour in saturated aquifers.
(28/07/2013)
BRGM, UNIGE, ISTerre, UJF, IFSTTAR, INSU - CNRS, USMB [Université de Savoie] [Université de Chambéry], CNRS, EPOC, EPHE, PSL, UB, INSU - CNRS, CNRS
Mercury concentrations in suspended particulate matter, water and mud-sediment un and downstream from old and recent gold mining sites in french Guiana
Although the use of mercury (Hg) for gold mining has been officially banned in French Guiana since 2006, there are still reasons to be wary of its occurrence in river water and its impact on local populations. In fact, gold-mining generates intense soil erosion and high turbidity in the rivers downstream from mining sites. This contributes to Hg pollution and dissemination both via the remobilization of Hg naturally present in the soils and the release of metallic Hg from the gold recovery process. In the affected rivers, Hg transport and speciation is mainly controlled by the suspended particulate matter (SPM) rather than remaining dissolved. The aim of this study is to understand and quantify the fate of this SPM-associated Hg along the Boulanger river affected by old and new gold mining activities. Furthermore we provide recent data (2012) essential to evaluate the efficiency of legal gold mining companies in restoring and re-planting exploited zones to control erosion, river turbidity and SPM transport. Inorganic Hg(II), monomethylmercury (MMHg) and turbidity measurements were measured in water, SPM and mud-sediment collected along the Boulanger River, from the spring down to its confluence with the Orapu River. The intensity of gold-mining in this area has been up and down through the last century and presents contrasting conditions with old and recently exploited areas. Dissolved Hg (HgD) levels were low (1-2 ng.L-1) and consistent with previous data known for the Amazonian area. Dissolved MMHg concentrations represented up to 8% of HgD which is higher than previous results (around 2%). Some relationships occurred between Hg concentrations in mud-sediment and turbidity values which both decreased downstream from the mining sites, then stabilized at 4-5 km further down. Hg contents in the mud-sediment show the impact of old (1.2 ng Hg.L-1) and new gold mining practices (~3 ng Hg.L-1). These concentrations were respectively 2 and 5 times higher than those near the river spring (0.61 ng.L-1). Moreover, Hg contents in sediment of artificial laguna (max measured 1.023 µg.g-1 Dry Matter) were up to 10 times the geochemical background of French Guiana sediment (0.1±0.05 µg.g-1) and did not show significant differences between old and new laguna. This suggests that Hg contents in mining-related particles released have not significantly changed for the so-called new mining. Accordingly, these results show that even though Hg use was banned from French Guiana 6 years ago, present gold mining practices still release significant amounts of Hg into the rivers. Survey intensification in French Guiana river systems should provide a more complete data set, essential to change gold mining practices and to reduce SPM and Hg contamination of the aquatic environment.
(28/07/2013)
BRGM, EPOC, EPHE, PSL, UB, INSU - CNRS, CNRS