Evaluation de la contamination atmosphérique des écosystèmes en utilisant la composition isotopique du plomb et du mercure dans les lichens

La signature isotopique du plomb (Pb) et du mercure (Hg) a été étudiée dans les lichens épiphytes des Pyrénées-Atlantiques. Un échantillonnage intégré et spatialisé à l aide d un système d information géographique (SIG) a été mis en place afin de prendre en compte la diversité du territoire (occupation des sols, forêts, agriculture, industries et zones urbaines). A méso-échelle (département des Pyrénées-Atlantiques), la composition isotopique permet de différencier les zones impactées par les activités anthropiques mais aussi de discriminer l origine de la contamination qu elle soit de type industrielle ou urbaine. A l échelle locale, la signature isotopique du Hg et Pb dans des lichens et des mousses prélevés dans la forêt d Iraty (zone frontalière Franco-espagnole) a permis d évaluer le type de dépôts accumulés dans ces différents bioaccumulateurs atmosphériques et le potentiel de ce nouvel outil pour le suivi des dépôts atmosphériques dans les écosystèmes éloignés. Enfin, sur la zone mercurifère d Almadén (Castella la Mancha, Espagne) la signature isotopique du Hg dans les lichens et les sédiments apparait comme un outil pertinent pour étudier le transfert du Hg provenant de l extraction minière vers les hydrosystèmes et l atmosphère.The isotopic signature of lead (Pb) and mercury (Hg) was measured in epiphytic lichens from Pyrénées-Atlantiques. An integrated and spatialized sampling was developed using geographical information system (GIS) to take into account the diversity of the territory (land-use, forest, agriculture, industries and urban areas). At meso-scale (county, Pyrenees-Atlantiques) the isotopic composition allows to differenciate areas impacted by anthropegenic activities and discriminate the origin of the contamination that it of industrial or urban type. At local scale, the isotopic signature of Hg and Pb in lichens and mosses sampled in Iraty forest (Franco-Spanish border) allowed to evaluate the kind of atmospheric deposits in these atmospheric bio-monitors and the potential of this new tool for the monitoring of atmospheric depositsin remote ecosystems. Finally, on the mercurifere area of Almadén (Castella la Mancha, Spain) the isotopic fingerprint of Hg in lichens and sediments appears to be a relevant tool to study the transfer of Hg from mining activities to hydrosystems and atmosphere.PAU-BU Sciences (644452103) / SudocSudocFranceF

Biogeochemical and contaminant cycling in sediments from a human-impacted coastal lagoon â Introduction and summary

International audienceFrom 2001 to 2003, the Microbent project (ââBiogeochemical processes at the water sediment interface in eutrophic environmentââ) was carried out within the framework of the Programme National Environnement CoËtier, the French contribution to LandeOcean Interaction in the Coastal Zone (LOICZ). The Microbent programme was focused on the study of sediment biogeochemical cycles of carbon, oxygen, sulphur, iron, nitrogen, and phosphorus in relation to the faunal activity in the sediment and their relation with the mobility of metallic contaminants at the sedimentewater interface (SWI) in a Mediterranean coastal lagoon (Thau lagoon, France; Fig. 1). The aim of Microbent was to set up an interdisciplinary study bringing together geochemists, sedimentologists, and biologists in order to understand and quantify the main reaction pathways, and the fluxes of contaminants at the SWI, including those related to benthic fauna. Work was focused on the processes which generate contaminant fluxes: (1) early diagenetic processes, which generate the chemical conditions of the environment; (2) processes leading to the transfer of contaminants from particles toward biofilms, water column, and organisms; and (3) processes of sediment mixing by organisms and sediment accumulation

Spatial distribution of mercury in seawater, sediment, and seafood from the Hardangerfjord ecosystem, Norway

International audienceHardangerfjord is one of the longest fjords in the world and has historical mercury (Hg) contamination from a zinc plant in its inner sector. In order to investigate the extent of Hg transferred to abiotic and biotic ecosystem compartments, Hg and monomethylmercury (MeHg) concentrations were measured in seawater, sediment, and seafood commonly consumed by humans. Although total mercury in seawater has been described previously, this investigation reports novel MeHg data for seawater from Norwegian fjords. Total Hg and MeHg concentrations in seawater, sediment, and biota increased towards the point source of pollution (PSP) and multiple lines of evidence show a clear PSP effect in seawater and sediment concentrations. In fish, however, similar high concentrations were found in the inner part of another branch adjacent to the PSP. We postulate that, in addition to PSP, atmospheric Hg, terrestrial run-off and hydroelectric power stations are also important sources of Hg in this fjord ecosystem. Hg contamination gradually increased towards the inner part of the fjord for most fish species and crustaceans. Since the PSP and the atmospheric Hg pools were greater towards the inner part of the fjord, it is not entirely possible to discriminate the full extent of the PSP and the atmospheric Hg contribution to the fjord food web. The European Union (EU) Hg maximum level for consumption was exceeded in demersal fish species including tusk (Brosme brosme), blue ling (Molva dypterygia) and common ling (Molva molva) from the inner fjord (1.08 to 1.89 mg kg−1 ww) and from the outer fjord (0.49 to 1.07 mg kg−1 ww). Crustaceans were less contaminated and only European lobster (Homarus gammarus) from inner fjord exceeded the EU limit (0.62 mg kg−1 ww). Selenium (Se) concentrations were also measured in seafood species and Se-Hg co-exposure dynamics are also discussed

Seasonal variation of mercury concentration of ancient olive groves of Lebanon

This study investigates the seasonality of the mercury (Hg) concentration of olive tree foliage, an iconic tree of the Mediterranean basin. Hg concentrations of foliage, stems, soil surface, and litter were analyzed on a monthly basis in ancient olive trees growing in two groves in Lebanon, Bchaaleh and Kawkaba (1300 and 672 m a.s.l. respectively). A significantly lower concentration was registered in stems (∼7–9 ng g−1) in comparison to foliage (∼35–48 ng g−1) in both sites, with the highest foliage Hg concentration in late winter–early spring and the lowest in summer. It is noteworthy that olive fruits also have low Hg concentrations (∼7–11 ng g−1). The soil has the highest Hg content (∼62–129 ng g−1) likely inherited through the cumulated litter biomass (∼63–76 ng g−1). A good covariation observed between our foliage Hg time series analysis and those of atmospheric Hg concentrations available for southern Italy in the western Mediterranean basin confirms that mercury pollution can be studied through olive trees. Spring sampling is recommended if the objective is to assess the trees' susceptibility to Hg uptake. Our study draws an adequate baseline for the eastern Mediterranean and the region with similar climatic inventories on Hg vegetation uptake, in addition to being a baseline to new studies on olive trees in the Mediterranean to reconstruct regional Hg pollution concentrations in the past and present.</p

Mercury human exposure through fish consumption in a reservoir contaminated by a chlor-alkali plant: Babeni reservoir (Romania)

Purpose: Chlor-alkali plants are one of the most important point sources of mercury to aquatic environment. The problem of Hg contamination has been studied in a region, Rm Valcea (Romania), impacted by the wastewater discharge of a chlor-alkali plant. The purpose of the present study is to evaluate the current status of mercury pollution in the Babeni reservoir (Olt River) and the exposure of local population via fish consumption to mercury originating from the chlor-alkali plant. Methods: Sediments were collected from Valcea, Govora and Babeni reservoirs. Grain size distribution, organic content and total mercury (THg) concentrations were analysed in sediments. Fish were purchased from local anglers, and the scalp hair was collected from volunteers. THg in sediment, fish and hair samples was determined using an atomic absorption spectrophotometer for Hg determination. Monomethylmercury (MMHg) was analysed in the muscle and liver tissues by species-specific isotope dilution and capillary gas chromatography hyphenated to inductively coupled plasma mass spectrometer. Results: High mercury concentrations were found in the sediments and in fish from Babeni reservoir, with a median of 2.1mg/kg (IQR = 3.2) in sediments and a mean value of 1.8 ± 0.8mg/kg_ww in fish muscle. MMHg concentrations in fish were well above the WHO guidelines for fish consumption. Local population consuming fish from the Babeni reservoir had THg concentrations in hair significantly higher than those consuming fish from upstream reservoirs and/or from the shops and reached a median value of 2.5mg/kg (IQR = 3.6). Conclusions: The remnant pollution in the fish of this reservoir, and probably many other lakes and reservoirs receiving Hg polluted wastewater, represents a considerable health risk for the local fish consumer

Rapid temporal decline of mercury in Greenland halibut (Reinhardtius hippoglossoides)

Mercury (Hg) pollution in the ocean is an issue of global concern, however bioaccumulation regimes of this ubiquitous pollutant in marine apex predators have important knowledge gaps. Our fish length and stable isotope (δ15N and δ13C) normalized data of Greenland halibut (GH) (Reinhardtius hippoglossoides) showed that Hg bioaccumulation in fillet tissue decreased by ~35–50 %, over a ten-year period from 2006 to 2015 (n = 7 individual sampling years). Hg was predominantly in the methylmercury form (>77 %). Results from a Bayesian information theoretic model showed that GH Hg concentrations decreased with time and its associated declines in Hg air emissions, estimated trophic position, and a potentially lower degree of demersal prey use as indicated by temporal trend shifts in nitrogen (δ15N) and carbon (δ13C) stable isotope values. GH trophic shifts accounted for about one third of the observed temporal reduction in Hg. Our study demonstrates the importance of simultaneously considering Hg emissions, food web dynamics and trophic shifts as important drivers of Hg bioaccumulation in a marine, deep water fish species and highlights the effectiveness of Hg regulations on ocean apex predator Hg concentrations and overall seafood safety.publishedVersio

Функционирование маркетинговых терминов в английском языке и способы их перевода на русский язык

Целью исследования является определение способов перевода английской терминологии на русский язык

Dynamics of mercury stable isotope compounds in Arctic seals: new insights from a controlled feeding trial on hooded seals Cystophora cristata.

peer reviewedAccurate interpretation of mercury (Hg) isotopic data requires the consideration of several biotic factors such as age, diet, geographical range, and tissue metabolic turnover. A priori knowledge of prey-predator isotopic incorporation rates and Hg biomagnification is essential. This study aims to assess Hg stable isotopes incorporation in an Arctic species of Phocidae, the hooded seal Cystophora cristata, kept in human care for 24 months (2012 - 2014) and fed on a constant diet of Norwegian Spring Spawning herring Clupea harengus. We measured THg, MMHg and iHg levels, as well as Hg stable isotope composition with both mass dependent (MDF) and mass independent (MIF) fractionation (e.g. δ202Hg and Δ199,200,201,204Hg) in hooded seal kidney, liver, hair and muscle, in addition to herring muscle. We then calculated Hg MDF and MIF isotopic fractionation between hooded seals and their prey. We found a significant shift in δ202Hg between hooded seal hair (+0.80‰) and kidney (-0.78‰), and herring muscle. In hooded seals tissues δ202Hg correlated positively with MMHg percentage. These findings suggest that tissue-specific Hg speciation is the major driver of changes in Hg isotopic fractionation rates in this Arctic predator. Δ199Hg, Δ200Hg, Δ201Hg and Δ204Hg values did not vary between herring and hooded seal tissues, confirming their utility as tracers of Hg marine and atmospheric sources in top predators. To our knowledge, this represents the first attempt to assess complex Hg isotope dynamics in the internal system of Arctic Phocidae, controlling the effects of age, diet, and distribution. Our results confirm the validity of Hg stable isotopes as tracers of environmental Hg sources even in top predators, but emphasize the importance of animal age and tissue selection for inter-study and inter-species comparisons.14. Life below wate

Shifts in mercury methylation across a peatland chronosequence: From sulfate reduction to methanogenesis and syntrophy

Peatlands are globally important ecosystems where inorganic mercury is converted to bioaccumulating and highly toxic methylmercury, resulting in high risks of methylmercury exposure in adjacent aquatic ecosystems. Although biological mercury methylation has been known for decades, there is still a lack of knowledge about the organisms involved in mercury methylation and the drivers controlling their methylating capacity. In order to investigate the metabolisms responsible for mercury methylation and methylmercury degradation as well as the controls of both processes, we studied a chronosequence of boreal peatlands covering fundamentally different biogeochemical conditions. Potential mercury methylation rates decreased with peatland age, being up to 53 times higher in the youngest peatland compared to the oldest. Methylation in young mires was driven by sulfate reduction, while methanogenic and syntrophic metabolisms became more important in older systems. Demethylation rates were also highest in young wetlands, with a gradual shift from biotic to abiotic methylmercury degradation along the chronosequence. Our findings reveal how metabolic shifts drive mercury methylation and its ratio to demethylation as peatlands age