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[en] Mosses, characterised by a slow growth, are able to efficiently accumulate different radionuclides from the environment to a much higher degree than other vegetation. Consequently, mosses are sensitive bioindicators of radioactive contamination in various ecosystems. Radioactivity released into air after the accident in the Fukushima Dai-ichi nuclear power plant has become part of atmospheric processes and the transport of matter in the biosphere. During the last five years, mosses were sampled at three selected locations: in the courtyard of the Institute for medical research in Zagreb (IMI), at an active gas well in Podravina (Molve) and near orchards and vineyards in Klostar Ivanic. Moss samples were before analysis dried in an oven and after that usually ashed. All the samples were analysed by means of gamma-ray spectrometry using HP GMX and/or Ge(Li) detectors connected with a data acquisition system. The obtained results show the following relations between 137Cs and 134Cs activity concentrations on selected locations: 137Cs: AKlostar < AIMI < AMolve 134Cs: AMolve < AKlostar < AIMI It is shown that the differences in 137Cs activity concentrations are statistically significant. There are at least two mechanisms present in mosses, one based on the transfer of metals (caesium) with dust uplifted from soil and the other one based on the diffusion in aqueous solution wetting a moss. We assume that the differences in the 137Cs activity concentrations are caused by the mosses growing at different locations with different fallout characteristics (wet and dry deposition). The 134Cs activity concentration is small everywhere, near the values of the detection limits. The study was conducted in the Radiation Protection Unit of the Institute for Medical Research and Occupational Health in Zagreb, as a part of an extensive monitoring program of the Croatian environment. (author).
[en] To develop an internationally standardized protocol for the moss bag technique application, the research team participating in the FP7 European project “MOSSclone” focused on the optimization of the moss bags exposure in terms of bag characteristics (shape of the bags, mesh size, weight/surface ratio), duration and height of exposure by comparing traditional moss bags to a new concept bag, “Mossphere”. In particular, the effects of each variable on the metal uptake from the air were evaluated by a systematic experimental design carried out in urban, industrial, agricultural and background areas of three European countries with oceanic, Mediterranean and continental climate. The results evidenced that the shape, the mesh size of the bags and the exposure height (in the tested ranges), did not significantly influence the uptake capacity of the transplanted moss. The aspects more affecting the element uptake were represented by the density of the moss inside the bags and the relative ratio between its weight and the surface area of the bag. We found that, the lower the density, the higher the uptake recorded. Moreover, three weeks of exposure were not enough to have a consistent uptake signal in all the environments tested, thus we suggest an exposure period not shorter than 6 weeks, which is appropriate in most situations. The above results were confirmed in all the countries and scenarios tested. The adoption of a shared exposure protocol by the research community is strongly recommended since it is a key aspect to make biomonitoring surveys directly comparable, also in view of its recognition as a monitoring method by the EU legislation. - Highlights: • Variables affecting moss bag uptake were tested by systematic experimental design. • Variables investigated were: shape, mesh size, density, height and exposure time. • A new concept bag “Mossphere” was developed. • Uptake effectiveness was evaluated in four scenarios of three EU countries. • The variables most affecting uptake are moss density and exposure time. - Variables significantly affecting moss bag uptake are exposure time and moss weight/bag surface ratio.
[en] The historical accumulation rates of mercury resulting from atmospheric deposition to four Scottish ombrotrophic peat bogs, Turclossie Moss (northeast Scotland), Flanders Moss (west-central), Red Moss of Balerno (east-central) and Carsegowan Moss (southwest), were determined via analysis of 210Pb- and 14C-dated cores up to 2000 years old. Average pre-industrial rates of mercury accumulation of 4.5 and 3.7 μg m-2 y-1 were obtained for Flanders Moss (A.D. 1-1800) and Red Moss of Balerno (A.D. 800-1800), respectively. Thereafter, mercury accumulation rates increased to typical maximum values of 51, 61, 77 and 85 μg m-2 y-1, recorded at different times possibly reflecting local/regional influences during the first 70 years of the 20th century, at the four sites (TM, FM, RM, CM), before declining to a mean value of 27 ± 15 μg m-2 y-1 during the late 1990s/early 2000s. Comparison of such trends for mercury with those for lead and arsenic in the cores and also with direct data for the declining UK emissions of these three elements since 1970 suggested that a substantial proportion of the mercury deposited at these sites over the past few decades originated from outwith the UK, with contributions to wet and dry deposition arising from long-range transport of mercury released by sources such as combustion of coal. Confidence in the chronological reliability of these core-derived trends in absolute and relative accumulation of mercury, at least since the 19th century, was provided by the excellent agreement between the corresponding detailed and characteristic temporal trends in the 206Pb/207Pb isotopic ratio of lead in the 210Pb-dated Turclossie Moss core and those in archival Scottish Sphagnum moss samples of known date of collection. The possibility of some longer-term loss of volatile mercury released from diagenetically altered older peat cannot, however, be excluded by the findings of this study.
[en] The purpose of this study was to demonstrate how to establish the area center (centroid) of both the soft and hard tissues of the outline of the lateral cephalometric skull image, and to introduce the concept of a new non-anatomical centroid line. Lateral cephalometric radiographs, size 12 x 14 inch, of fifty seven adult subjects were selected based on their pleasant, balanced profile, Class I skeletal and dental relationship and no major dental malocclusion or malrelationship. The area centers (centroids) of both soft and hard tissue skull were practically established using a customized software computer program called the m-file. Connecting the two centers introduced the concept of a new non-anatomical soft and hard centroids line. (author)
[en] In this study we examined 6080 data gathered by our research group during more than 20 years of research on the moss biomonitoring technique, in order to quantify the variability generated by different aspects of the protocol and to calculate the overall measurement uncertainty associated with the technique. The median variance of the concentrations of different pollutants measured in moss tissues attributed to the different methodological aspects was high, reaching values of 2851 (ng·g−1)2 for Cd (sample treatment), 35.1 (μg·g−1)2 for Cu (sample treatment), 861.7 (ng·g−1)2 and for Hg (material selection). These variances correspond to standard deviations that constitute 67, 126 and 59% the regional background levels of these elements in the study region. The overall measurement uncertainty associated with the worst experimental protocol (5 subsamples, refrigerated, washed, 5 × 5 m size of the sampling area and once a year sampling) was between 2 and 6 times higher than that associated with the optimal protocol (30 subsamples, dried, unwashed, 20 × 20 m size of the sampling area and once a week sampling), and between 1.5 and 7 times higher than that associated with the standardized protocol (30 subsamples and once a year sampling). The overall measurement uncertainty associated with the standardized protocol could generate variations of between 14 and 47% in the regional background levels of Cd, Cu, Hg, Pb and Zn in the study area and much higher levels of variation in polluted sampling sites. We demonstrated that although the overall measurement uncertainty of the technique is still high, it can be reduced by using already well defined aspects of the protocol. Further standardization of the protocol together with application of the information on the overall measurement uncertainty would improve the reliability and comparability of the results of different biomonitoring studies, thus extending use of the technique beyond the context of scientific research. - Highlights: • The overall measurement uncertainty associated with the moss technique was calculated. • Uncertainty decreased when using the worst vs. standardized vs. optimal experimental set up. • Although the overall uncertainty of the technique is still high, it can be reduced. • Standardization of the protocol improves the reliability and comparability of the results. - Measurement uncertainty associated to the results of the moss technique is significantly reduced when applying a standardized protocol.
[en] Nitrogen deposition at current ambient levels in Wales is detrimental to shoot growth of Racomitrium lanuginosum. - Racomitrium lanuginosum shoot growth was studied under the combined effects of N deposition (0, 20, 40 and 60 kg N ha-1 year-1), competition with Festuca ovina, and a drought pre-treatment. Moss regeneration from shoot fragments was also investigated. Growth was initially stimulated at the 60 kg N level. However, after 6 months, growth was lower in all N treatments than in the 0 kg N control. Reductions in shoot growth first became apparent in the pre-desiccated moss, while moss shoots grew longer when surrounded by a F. ovina canopy. Optimum regeneration occurred at 20-40 kg N on bare soil, and at 0-20 kg N under a F. ovina canopy. These results suggest that current N deposition in upland Wales is already detrimental to growth of this species, and to regeneration under certain conditions. This species may be affected under predicted climatic scenarios of increased summer drought in Britain
[en] The activity of 137Cs was determined in soils, mosses, lichens and other vegetation along the Caruay River and near the town of Kavanayen. The range of values for the soils was from <1.2 Bq x kg-1 of 137Cs (our detection limit) to 14.1 Bq x kg-1. The range of 137Cs activities in the mosses ranged from 9.9 to 17.9 Bq x kg-1 with a mean value of 13.4±4 Bq x kg-1; all the moss samples were found along the river. While the 137Cs activities in the lichens ranged from 9.1 to 29.8 Bq x kg-1; the two values along the river were about three factors higher than the one near Kavanayen. It was concluded that the 137Cs activities in the soils, mosses and lichens are much higher along the river in respect to the nearby town of Kavanayen
[en] In 2005/6, nearly 3000 moss samples from (semi-)natural location across 16 European countries were collected for nitrogen analysis. The lowest total nitrogen concentrations in mosses (<0.8%) were observed in northern Finland and northern UK. The highest concentrations (≥1.6%) were found in parts of Belgium, France, Germany, Slovakia, Slovenia and Bulgaria. The asymptotic relationship between the nitrogen concentrations in mosses and EMEP modelled nitrogen deposition (averaged per 50 km x 50 km grid) across Europe showed less scatter when there were at least five moss sampling sites per grid. Factors potentially contributing to the scatter are discussed. In Switzerland, a strong (r2 = 0.91) linear relationship was found between the total nitrogen concentration in mosses and measured site-specific bulk nitrogen deposition rates. The total nitrogen concentrations in mosses complement deposition measurements, helping to identify areas in Europe at risk from high nitrogen deposition at a high spatial resolution. - Highlights: → Nitrogen concentrations in mosses were determined at ca. 3000 sites across Europe. → Moss concentrations were compared with EMEP modelled nitrogen deposition. → The asymptotic relationship for Europe showed saturation at ca. 15 kg N ha-1 y-1. → Linear relationships were found with measured nitrogen deposition in some countries. → Moss concentrations complement deposition measurements at high spatial resolution. - Mosses as biomonitors of atmospheric nitrogen deposition in Europe.
[en] The structural simplicity of the bryophytes exposed them easily to water stress, forcing them to have physiological and biochemical mechanisms that enable them to survive. This study evaluated the variation of total soluble sugars and reducing sugars in relation to relative water content, in Pleurozium schreberi when faced with low water content in the Paramo de Chingaza (Colombia) and under simulated conditions of water deficit in the laboratory. we found that total sugars increase when the plant is dehydrated and returned to their normal content when re-hydrated moss, this could be interpreted as a possible mechanism of osmotic adjustment and osmoprotection of the cell content and cellular structure. Reducing sugars showed no significant variation, showing that monosaccharides do not have a protective role during dehydration.
[en] Under consideration is the mechanism of multiwalled nanotubes formation during mechanical activation of amorphous carbon synthesized by pyrolysis of sphagnum moss. The formation of nanotubes has been shown to take place in the array of carbon particles. A complex study of the sorption characteristics of carbon nanotubes has been carried out. The dependence of the sorption capacity of carbon nanotubes on their storage time, as well as the effect of the process parameters of nanotubes formation on their ability for oxidative modification, is represented. (authors)