Current and future levels of mercury atmospheric pollution on global scale

An assessment of current and future emissions, air concentrations and atmospheric deposition of mercury world-wide are presented on the basis of results obtained during the performance of the EU GMOS (Global Mercury Observation System) project. Emission estimates for mercury were prepared with the main goal of applying them in models to assess current (2013) and future (2035) air concentrations and atmospheric deposition of this contaminant. The artisanal and small- scale gold mining, as well as combustion of fossil fuels (mainly coal) for energy and heat production in power plants and in industrial and residential boilers are the major anthropogenic sources of Hg emissions to the atmosphere at present. These sources account for about 37 % and 25 % of the total anthropogenic Hg emissions globally, estimated to be about 2000 tonnes. The emissions in Asian countries, particularly in China and India dominate the total emissions of Hg. The current estimate of mercury emissions from natural processes (primary mercury emissions and re-emissions), including mercury depletion events, were estimated to be 5207 tonnes per year which represent nearly 70 % of the global mercury emission budget. Oceans are the most important sources (36 %) followed by biomass burning (9 %). A comparison of the 2035 anthropogenic emissions estimated for 3 different scenarios with current anthriopogenic emissions indicates a reduction of these emissions in 2035 up to 85 % for the best case scenario. Two global chemical transport models (GLEMOS and ECHMERIT) have been used for the evaluation of future Hg pollution levels considering future emission scenarios. Projections of future changes in Hg deposition on a global scale simulated by these models for three anthropogenic emissions scenarios of 2035 indicate a decrease of up to 50 % deposition in the Northern Hemisphere and up to 35 % in Southern Hemisphere for the best case scenario. The EU GMOS project has proved to be a very important research instrument for supporting, first the scientific justification for the Minamata Convention, and then monitoring of the implementation of targets of this Convention, as well as, the EU Mercury Strategy. This project provided the state-of-the art with regard to the development of the latest emission inventories for mercury, future emission scenarios, dispersion modelling of atmospheric Hg on global and regional scale, and source – receptor techniques for Hg emission apportionment on a global scale.</p

Current and future levels of mercury atmospheric pollution on a global scale

An assessment of current and future emissions, air concentrations, and atmospheric deposition of mercury worldwide is presented on the basis of results obtained during the performance of the EU GMOS (Global Mercury Observation System) project. Emission estimates for mercury were prepared with the main goal of applying them in models to assess current (2013) and future (2035) air concentrations and atmospheric deposition of this contaminant. The combustion of fossil fuels (mainly coal) for energy and heat production in power plants and in industrial and residential boilers, as well as artisanal and small-scale gold mining, is one of the major anthropogenic sources of Hg emissions to the atmosphere at present. These sources account for about 37 and 25 % of the total anthropogenic Hg emissions globally, estimated to be about 2000 t. Emissions in Asian countries, particularly in China and India, dominate the total emissions of Hg. The current estimates of mercury emissions from natural processes (primary mercury emissions and re-emissions), including mercury depletion events, were estimated to be 5207 t year⁻¹, which represents nearly 70 % of the global mercury emission budget. Oceans are the most important sources (36 %), followed by biomass burning (9 %). A comparison of the 2035 anthropogenic emissions estimated for three different scenarios with current anthropogenic emissions indicates a reduction of these emissions in 2035 up to 85 % for the best-case scenario. <br><br> Two global chemical transport models (GLEMOS and ECHMERIT) have been used for the evaluation of future mercury pollution levels considering future emission scenarios. Projections of future changes in mercury deposition on a global scale simulated by these models for three anthropogenic emissions scenarios of 2035 indicate a decrease in up to 50 % deposition in the Northern Hemisphere and up to 35 % in Southern Hemisphere for the best-case scenario. <br><br> The EU GMOS project has proved to be a very important research instrument for supporting the scientific justification for the Minamata Convention and monitoring of the implementation of targets of this convention, as well as the EU Mercury Strategy. This project provided the state of the art with regard to the development of the latest emission inventories for mercury, future emission scenarios, dispersion modelling of atmospheric mercury on a global and regional scale, and source–receptor techniques for mercury emission apportionment on a global scale

European Jurassic floras : statistics and palaeoenvironmental proxies

The Jurassic floras of Europe show considerable diversity. To examine the extent of this diversity and its possible causes we used multivariate statistical methods (cluster analysis, PCA, NMDS) to compare all significant Jurassic floras in Europe. Data were based on 770 taxa from 46 fossiliferous occurrences (25 units) from France, Germany, Greenland, Hungary, Italy, Norway, Poland, Romania, Scotland, Serbia, Sweden, Switzerland, and the United Kingdom. Statistical analyses were applied at species level and genus level, and also performed for the major plant groups. The genus cladograms show affinities between different localities based on environmental factors, while the cladograms based on species affinities indicate only taxonomical correlations. The study shows that locality age does not seem to be of paramount importance for floral composition

Tumor suppression in mice lacking GABARAP, an Atg8/LC3 family member implicated in autophagy, is associated with alterations in cytokine secretion and cell death

GABARAP belongs to an evolutionary highly conserved gene family that has a fundamental role in autophagy. There is ample evidence for a crosstalk between autophagy and apoptosis as well as the immune response. However, the molecular details for these interactions are not fully characterized. Here, we report that the ablation of murine GABARAP, a member of the Atg8/LC3 family that is central to autophagosome formation, suppresses the incidence of tumor formation mediated by the carcinogen DMBA and results in an enhancement of the immune response through increased secretion of IL-1β, IL-6, IL-2 and IFN-γ from stimulated macrophages and lymphocytes. In contrast, TGF-β1 was significantly reduced in the serum of these knockout mice. Further, DMBA treatment of these GABARAP knockout mice reduced the cellularity of the spleen and the growth of mammary glands through the induction of apoptosis. Gene expression profiling of mammary glands revealed significantly elevated levels of Xaf1, an apoptotic inducer and tumor-suppressor gene, in knockout mice. Furthermore, DMBA treatment triggered the upregulation of pro-apoptotic (Bid, Apaf1, Bax), cell death (Tnfrsf10b, Ripk1) and cell cycle inhibitor (Cdkn1a, Cdkn2c) genes in the mammary glands. Finally, tumor growth of B16 melanoma cells after subcutaneous inoculation was inhibited in GABARAP-deficient mice. Together, these data provide strong evidence for the involvement of GABARAP in tumorigenesis in vivo by delaying cell death and its associated immune-related response

Trace metals in aerosol at Terra Nova Bay, Antarctica.

Atmospheric particulate with an aerodynamic diameter o10 mm (PM10) was sampled continuously during the austral summers of 2000–2001 and 2001–2002 at a coastal site near to the Italian base of Terra Nova, Antarctica. Li, Pb, Cd, U, Ba, Bi, Cs, Rb, Tl, Sr, Al, V, Fe, Cu, Mn, Zn, Co, Ag were determined by inductively coupled sector field mass spectroscopy (ICP-SFMS) after sample digestion by a combination of HF, HNO3, and H2O2 in ultraclean conditions. Quality control of the analytical procedure was carried out by blank control, by evaluating the limits of detection, recoveries and repeatability. Concentrations found are extremely low for most metals, confirming the high purity of Antarctic aerosol. Principal Component Analysis (PCA) highlights high correlations among Pb, Cr, Bi, Cu and Zn concentration values and among Li, U, Ba, Cs, Rb, Al, V, Fe, Mn, Co concentration values permitting the identification of two principal source groups, namely crustal dust and human emission activities. Elements of anthropogenic origins (Pb, Cr, Cu, Zn) were highly enriched with respect to their crustal composition

Red Fox Vulpes vulpes (L., 1758) as a Bioindicator of Mercury Contamination in Terrestrial Ecosystems of North-Western Poland

In this study, we determined the concentrations of total mercury (Hg) in samples of liver, kidney and skeletal muscle of 27 red foxes Vulpes vulpes (L., 1758) from north-western Poland, and examined the morphometric characteristics of the collected specimens. The analysis also included the relationship between Hg concentration and the fox size, and the suitability of individual organs as bioindicators in indirect evaluation of environmental mercury contamination. Determination of Hg concentration was performed by atomic absorption spectroscopy. In the analysed samples, the Hg concentration was low and the maximum value did not exceed 0.85 mgHg/kg dry weight (dw). There were no significant differences in Hg concentrations in the analysed material between males and females or between immature and adult groups. The median concentrations of Hg in the liver, kidney and skeletal muscle were 0.22, 0.11 and 0.05 mgHg/kg dw, respectively. The correlation coefficients were significant between the concentrations of mercury in the liver, kidney and skeletal muscle (positive) and between the kidney Hg concentration and kidney mass (negative). Taking into account our results and findings of other authors, it may be argued that the red fox exhibits a measurable response to mercury environmental pollution and meets the requirements of a bioindicator

Tumor to normal single-cell mRNA comparisons reveal a pan-neuroblastoma cancer cell

Neuroblastoma is a childhood cancer that resembles developmental stages of the neural crest. It is not established what developmental processes neuroblastoma cancer cells represent. Here, we sought to reveal the phenotype of neuroblastoma cancer cells by comparing cancer (n = 19,723) with normal fetal adrenal single-cell transcriptomes (n = 57,972). Our principal finding was that the neuroblastoma cancer cell resembled fetal sympathoblasts, but no other fetal adrenal cell type. The sympathoblastic state was a universal feature of neuroblastoma cells, transcending cell cluster diversity, individual patients, and clinical phenotypes. We substantiated our findings in 650 neuroblastoma bulk transcriptomes and by integrating canonical features of the neuroblastoma genome with transcriptional signals. Overall, our observations indicate that a pan-neuroblastoma cancer cell state exists, which may be attractive for novel immunotherapeutic and targeted avenues

Optimization of the Strength-Fracture Toughness Relation in Particulate-Reinforced Aluminum Composites via Control of the Matrix Microstructure

The article of record as published may be found at http://dx.doi.org/10.1007/s11661-998-0119-9The evolution of the microstructure and mechanical properties of a 17.5 vol. pct SiC particulatereinforced aluminum alloy 6092-matrix composite has been studied as a function of postfabrication processing and heat treatment. It is demonstrated that, by the control of particulate distribution, matrix grain, and substructure and of the matrix precipitate state, the strength-toughness combination in the composite can be optimized over a wide range of properties, without resorting to unstable, underaged (UA) matrix microstructures, which are usually deemed necessary to produce a higher fracture toughness than that displayed in the peak-aged condition. Further, it is demonstrated that, following an appropriate combination of thermomechanical processing and unconventional heat treatment, the composite may possess better stiffness, strength, and fracture toughness than a similar unreinforced alloy. In the high- and low-strength matrix microstructural conditions, the matrix grain and substructure were found to play a substantial role in determining fracture properties. However, in the intermediate- strength regime, properties appeared to be optimizable by the utilization of heat treatments only. These observations are rationalized on the basis of current understanding of the grain size dependence of fracture toughness and the detailed microstructural features resulting from thermomechanical treatments.United States Army Research OfficeArmy Research LabratoryUnited States Air Force Office of Scientific ResearchWright Materials LabratoryDWA Composite

Return of naturally sourced Pb to Atlantic surface waters

Anthropogenic emissions completely overwhelmed natural marine lead (Pb) sources during the past century, predominantly due to leaded petrol usage. Here, based on Pb isotope measurements, we reassess the importance of natural and anthropogenic Pb sources to the tropical North Atlantic following the nearly complete global cessation of leaded petrol use. Significant proportions of up to 30-50% of natural Pb, derived from mineral dust, are observed in Atlantic surface waters, reflecting the success of the global effort to reduce anthropogenic Pb emissions. The observation of mineral dust derived Pb in surface waters is governed by the elevated atmospheric mineral dust concentration of the North African dust plume and the dominance of dry deposition for the atmospheric aerosol flux to surface waters. Given these specific regional conditions, emissions from anthropogenic activities will remain the dominant global marine Pb source, even in the absence of leaded petrol combustion

Lead content and isotopic composition in submound and recent soils of the Volga upland

Literature data on the historical reconstructions of the atmospheric lead deposition in Europe and the isotopic composition of the ores that are potential sources of the anthropogenic lead in the atmospheric deposition in the lower Volga steppes during different time periods have been compiled. The effect of the increasing anthropogenic lead deposition recorded since the Bronze Age on the level of soil contamination has been investigated. For the first time paleosol buried under a burial mound of the Bronze Age has been used as a reference point to assess of the current contamination level. The contents and isotopic compositions of the mobile and total lead have been determined in submound paleosols of different ages and their recent remote and roadside analogues. An increase in the content and fraction of the mobile lead and a shift of its isotopic composition toward less radiogenic values (typical for lead from the recent anthropogenic sources) has been revealed when going from a Bronze-Age paleosol to a recent soil. In the Bronze-Age soil, the isotopic composition of the mobile lead is inherited from the parent rock to a greater extent than in the modern soils, where the lead is enriched with the less radiogenic component. The effect of the anthropogenic component is traced in the analysis of the mobile lead, but it is barely visible for the total lead. An exception is provided by the recent roadside soils characterized by increased contents and the significantly less radiogenic isotopic composition of the mobile and total lead