Iceberg lettuce is one of the most consumed leafy vegetables, which is often treated by different pesticides against pests and diseases. The aim of this study was to describe the fate of 25 pesticides (16 fungicides, 7 insecticides and 2 herbicides) based on quantitative analysis of the parent compounds and targeted screening of their (bio)transformation products. Mathematical models describing a decrease in pesticide residue levels were proposed for 24 pesticides using a first-order kinetic equation. These models provide the data needed to predict consumer exposure associated with the consumption of conventionally grown iceberg lettuce. At harvest, concentrations of most pesticides were dropped under the established EU maximum residue levels, except for flonicamid, fluazifop and pyriproxyfen. A total of 113 pesticide metabolites and degradation products were detected and tentatively identified in extracts prepared by an optimized extraction procedure, i.e., the acidified QuEChERS method. Several products of reactions such as hydrolysis, dealkylation, dehalogenation and/or oxidation-reduction, originated either from various physicochemical processes, or within Phase I pesticide metabolism were detected. Additionally, numerous conjugates with hexose, malonic acid or acetic acid formed during PhaseII of pesticide metabolism were found. In this way, a deeper understanding of specific pesticide degradation mechanisms is facilitated. In addition, it is easier to track the history of pesticide treatment.

• MeSH
• herbicidy analýza   MeSH
• kinetika MeSH
• kontaminace potravin * analýza   MeSH
• rezidua pesticidů * analýza   MeSH
• salát (hlávkový) * chemie   MeSH
• Publikační typ
• časopisecké články MeSH

Permafrost controls geomorphological dynamics in maritime Antarctic ecosystems. Here, we analyze and model ground thermal regime in bordering conditions between continuous and discontinuous permafrost to better understand its relationship with the timing of glacial retreat. In February 2017, a transect including 10 sites for monitoring ground temperatures was installed in the eastern fringe of Byers Peninsula (Livingston Island, northern Antarctic Peninsula), together with one station recording air temperatures and snow thickness. The sites were selected following the Mid-Late Holocene deglaciation of the area at a distance ranging from 0.30 to 3.15 km from the current Rotch Dome glacier front. The transect provided data on the effects of topography, snow cover and the timing of ice-free exposure, on the ground thermal regime. From February 2017 to February 2019, the mean annual air temperature was -2.0 °C, which was >0.5 °C higher than 1986-2015 average in the Western Antarctic Peninsula region. Mean annual ground temperature at 10 cm depth varied between 0.3 and -1.1 °C, similar to the modelled Temperatures on the Top of the Permafrost (TTOP) that ranged from 0.06 ± 0.08 °C to -1.33 ± 0.07 °C. The positive average temperatures at the warmest site were related to the long-lasting presence of snow which favoured warmer ground temperatures and may trigger permafrost degradation. The role of other factors (topography, and timing of the deglaciation) explained intersite differences, but the overall effect was not as strong as snow cover.

• MeSH
• ekosystém MeSH
• ledový příkrov MeSH
• ostrovy MeSH
• permafrost * MeSH
• teoretické modely * MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH
• Geografické názvy
• Antarktida MeSH
• ostrovy MeSH

In previous studies, the incorporation of polychlorinated biphenyls (PCBs) has been quantified in the accumulation areas of Alpine glaciers. Here, we introduce a model framework that quantifies mass fluxes of PCBs in glaciers and apply it to the Silvretta glacier (Switzerland). The models include PCB incorporation into the entire surface of the glacier, downhill transport with the flow of the glacier ice, and chemical fate in the glacial lake. The models are run for the years 1900-2100 and validated by comparing modeled and measured PCB concentrations in an ice core, a lake sediment core, and the glacial streamwater. The incorporation and release fluxes, as well as the storage of PCBs in the glacier increase until the 1980s and decrease thereafter. After a temporary increase in the 2000s, the future PCB release and the PCB concentrations in the glacial stream are estimated to be small but persistent throughout the 21st century. This study quantifies all relevant PCB fluxes in and from a temperate Alpine glacier over two centuries, and concludes that Alpine glaciers are a small secondary source of PCBs, but that the aftermath of environmental pollution by persistent and toxic chemicals can endure for decades.

• MeSH
• chemické látky znečišťující vodu MeSH
• jezera MeSH
• ledový příkrov * MeSH
• monitorování životního prostředí MeSH
• polychlorované bifenyly * MeSH
• teoretické modely MeSH
• Publikační typ
• časopisecké články MeSH
• Geografické názvy
• Švýcarsko MeSH

The biogeographic history of lichenized fungi remains unrevealed because those organisms rarely fossilize due to their delicate, often tiny and quickly rotting thalli. Also the ecology and factors limiting occurrence of numerous taxa, especially those restricted in their distribution to tropical areas are poorly recognized. The aim of this study was to determine localization of glacial refugia of South American Ochrolechia austroamericana and to estimate the future changes in the coverage of its habitats using ecological niche modeling tools. The general glacial potential range of the studied species was wider than it is nowadays and its niches coverage decreased by almost 25% since last glacial maximum. The refugial areas were covered by cool and dry grasslands and scrubs and suitable niches in South America were located near the glacier limit. According to our analyses the further climate changes will not significantly influence the distribution of the suitable niches of O. austroamericana.

• MeSH
• ekosystém * MeSH
• ledový příkrov * MeSH
• lišejníky fyziologie   MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH
• Geografické názvy
• Jižní Amerika MeSH

Fresh produce that is contaminated with viruses may lead to infection and viral gastroenteritis or hepatitis when consumed raw. It is thus important to reduce virus numbers on these foods. Prevention of virus contamination in fresh produce production and processing may be more effective than treatment, as sufficient virus removal or inactivation by post-harvest treatment requires high doses that may adversely affect food quality. To date knowledge of the contribution of various potential contamination routes is lacking. A risk assessment model was developed for human norovirus, hepatitis A virus and human adenovirus in raspberry and salad vegetable supply chains to quantify contributions of potential contamination sources to the contamination of produce at retail. These models were used to estimate public health risks. Model parameterization was based on monitoring data from European supply chains and literature data. No human pathogenic viruses were found in the soft fruit supply chains; human adenovirus (hAdV) was detected, which was additionally monitored as an indicator of fecal pollution to assess the contribution of potential contamination points. Estimated risks per serving of lettuce based on the models were 3×10(-4) (6×10(-6)-5×10(-3)) for NoV infection and 3×10(-8) (7×10(-10)-3×10(-6)) for hepatitis A jaundice. The contribution to virus contamination of hand-contact was larger as compared with the contribution of irrigation, the conveyor belt or the water used for produce rinsing. In conclusion, viral contamination in the lettuce and soft fruit supply chains occurred and estimated health risks were generally low. Nevertheless, the 97.5% upper limit for the estimated NoV contamination of lettuce suggested that infection risks up to 50% per serving might occur. Our study suggests that attention to full compliance for hand hygiene will improve fresh produce safety related to virus risks most as compared to the other examined sources, given the monitoring results. This effect will be further aided by compliance with other hygiene and water quality regulations in production and processing facilities.

• MeSH
• hepatitida A prevence a kontrola   MeSH
• hodnocení rizik MeSH
• hygiena rukou MeSH
• infekce viry z čeledi Caliciviridae prevence a kontrola   MeSH
• kvalita vody MeSH
• lidé MeSH
• lidské adenoviry izolace a purifikace   fyziologie   MeSH
• Norovirus izolace a purifikace   fyziologie   MeSH
• ovoce virologie   MeSH
• salát (hlávkový) virologie   MeSH
• teoretické modely * MeSH
• virus hepatitidy A izolace a purifikace   fyziologie   MeSH
• Check Tag
• lidé MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH

Clearwater Mesa (James Ross Island, northeast Antarctic Peninsula) provides a unique opportunity to study solute dynamics and geochemical weathering in the pristine lacustrine systems of a high latitude environment. In order to determine major controls on the solute composition of these habitats, a geochemical survey was conducted on 35 lakes. Differences between lakes were observed based on measured physico-chemical parameters, revealing neutral to alkaline waters with total dissolved solids (TDS) < 2500 mg L-1. Katerina and Trinidad-Tatana systems showed an increase in their respective TDS, total organic carbon values, and finner sediments from external to internal lakes, indicating an accumulation of solutes due to weathering. Norma and Florencia systems exhibited the most diluted and circumneutral waters, likely from the influence of glacier and snow melt. Finally, isolated lakes presented large variability in TDS values, indicating weathering and meltwater contributions at different proportions. Trace metal abundances revealed a volcanic mineral weathering source, except for Pb and Zn, which could potentially indicate atmospheric inputs. Geochemical modelling was also conducted on a subset of connected lakes to gain greater insight into processes determining solute composition, resulting in the weathering of salts, carbonates and silicates with the corresponding generation of clays. We found CO2 consumption accounted for 20-30% of the total species involved in weathering reactions. These observations allow insights into naturally occurring geochemical processes in a pristine environment, while also providing baseline data for future research assessing the impacts of anthropogenic pollution and the effects of climate change.

• MeSH
• ekosystém MeSH
• geologické sedimenty chemie   MeSH
• jezera chemie   MeSH
• klimatické změny MeSH
• ledový příkrov chemie   MeSH
• minerály analýza   MeSH
• monitorování životního prostředí metody   MeSH
• olovo analýza   MeSH
• organické látky analýza   MeSH
• počasí MeSH
• stopové prvky analýza   MeSH
• uhličitany analýza   MeSH
• zinek analýza   MeSH
• Publikační typ
• časopisecké články MeSH
• Geografické názvy
• Antarktida MeSH
• Trinidad a Tobago MeSH

BACKGROUND: Quaternary climate fluctuations are an engine of biotic diversification. Global cooling cycles, such as the Last Glacial Maximum (LGM), are known to have fragmented the ranges of higher-latitude fauna and flora into smaller refugia, dramatically reducing species ranges. However, relatively less is known about the effects of cooling cycles on tropical biota. RESULTS: We analyzed thousands of genome-wide DNA markers across an assemblage of three closely related understorey-inhabiting scrubwrens (Sericornis and Aethomyias; Aves) from montane forest along an elevational gradient on Mt. Wilhelm, the highest mountain of Papua New Guinea. Despite species-specific differences in elevational preference, we found limited differentiation within each scrubwren species, but detected a strong genomic signature of simultaneous population expansions at 27-29 ka, coinciding with the onset of the LGM. CONCLUSION: The remarkable synchronous timing of population expansions of all three species demonstrates the importance of global cooling cycles in expanding highland habitat. Global cooling cycles have likely had strongly different impacts on tropical montane areas versus boreal and temperate latitudes, leading to population expansions in the former and serious fragmentation in the latter.

• MeSH
• biologická evoluce * MeSH
• databáze jako téma MeSH
• druhová specificita MeSH
• ekosystém * MeSH
• fylogeneze MeSH
• fylogeografie MeSH
• jednonukleotidový polymorfismus genetika   MeSH
• ledový příkrov * MeSH
• nadmořská výška MeSH
• počítačová simulace MeSH
• populační genetika MeSH
• pravděpodobnost MeSH
• sekvence nukleotidů MeSH
• zeměpis MeSH
• zpěvní ptáci růst a vývoj   MeSH
• zvířata MeSH
• Check Tag
• zvířata MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH
• Geografické názvy
• Papua Nová Guinea MeSH

New species are generated by many means, among which hybridization plays an important role. Interspecific hybrids can form isolated evolutionary units, especially when mechanisms increasing viability and fertility, like polyploidy and apomixis, are involved. A good model system to study reticulate evolution in plants is Rubus subgen. Rubus (brambles, blackberries), which only in Europe includes 748 accepted species, out of which only four are sexual diploids and all others are polyploid apomicts. We employed two molecular markers (ITS and cpDNA) to shed light on the evolutionary history of European bramble flora and main processes generating such high species diversity. We distinguished just six ancestral diploids (including two extinct ones) for both markers, which gave rise to all European polyploid accessions, and revealed an extreme reticulation in bramble evolution. We furthermore detected hybridogenous origins and identified putative parents for several taxa (e.g. ser. Nessenses), while in other groups (e.g. ser. Discolores) we could also infer the direction of hybridization. By comparing different cp haplotypes having clear geographic patterns, we hypothesize that the origin of European brambles can be attributed to both Holocene species range expansion and Pleistocene climate fluctuations.

• MeSH
• apomixie * genetika   MeSH
• diploidie MeSH
• DNA chloroplastová genetika   MeSH
• fylogeneze MeSH
• genetické markery genetika   MeSH
• hybridizace genetická genetika   MeSH
• ledový příkrov MeSH
• mezerníky ribozomální DNA genetika   MeSH
• modely genetické * MeSH
• molekulární evoluce * MeSH
• polyploidie MeSH
• Rubus klasifikace   genetika   MeSH
• sekvenční analýza DNA MeSH
• vznik druhů (genetika) * MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH
• Geografické názvy
• Evropa MeSH

The objective of this study is to characterize changes in the fate, behaviour and bioavailability of four conazole fungicides - CFs (prochloraz - PRO, tebuconazole - TEB, epoxiconazole - EPO, flusilazole - FLU) in 12 diverse agricultural soils in complex microcosm systems consisting of agriculturally-used fluvisols, plants (Lactuca sativa), earthworms (Eisenia fetida) and passive samplers (SPME, Empore™ discs, silicone rubber). Due to great variability of the data and other methodological problems, the in-matrix passive samplers failed to be indicators of pore-water concentration and (bio)availability/(bio)accessibility of CFs. A dissipation of all CFs followed the first order kinetics (usually after initial lag phase) with large span of resulting half-lives (7-670 d) depending on soils and compounds. In many soils, the model revealed the ending plateau, which indicates the non-degradable or slowly-degradable residues. The half-lives and the residues were generally higher for EPO and FLU, than for PRO and TEB. Greater but slower total dissipation of CFs was observed in soils with higher percentage of organic matter. Earthworm concentrations were highest at first sampling time (14 days) and considerably decreased afterwards often resulting in PRO concentration below LOQ. Earthworm uptake was influenced by amount of organic matter and soil texture. Accumulation to lettuce roots was generally higher than to leaves and differed greatly among CFs. Concentration shoot to root ratios were generally the lowest for FLU (0.04) and highest for TEB (0.37). PRO was not detected in lettuce leaves during experiment. The study brings new results on fate and bioavailability of CFs in soils.

• MeSH
• biologická dostupnost MeSH
• látky znečišťující půdu analýza   MeSH
• Oligochaeta chemie   MeSH
• průmyslové fungicidy analýza   MeSH
• půda chemie   MeSH
• salát (hlávkový) chemie   MeSH
• triazoly analýza   MeSH
• zemědělství MeSH
• zvířata MeSH
• Check Tag
• zvířata MeSH
• Publikační typ
• časopisecké články MeSH

BACKGROUND: Urban particulate matter (PM) can affect green plants either via deposition on the above-ground biomass, where the contaminants can penetrate the leaf surface, or indirectly via soil-root interaction. This experiment assessed the potential risk of PM-derived risk elements contained in vegetables. The bioavailable portions of arsenic (As), cadmium (Cd), iron (Fe), and zinc (Zn) in leafy vegetables amended by PM via soil and/or foliar application were investigated in a model pot experiment, in which lettuce and chard were cultivated. RESULTS: By using the physiologically based extraction test simulating in vitro human digestive processes in the stomach and small intestine, the bioavailable portions of toxic elements from PM-amended plant biomass were extracted. Extractable portions of elements by a simulated gastric solution from biomass decreased for lettuce in the order Zn > Cd > As > Fe; while for chard, the order was As > Zn > Cd > Fe. No significant effects of PM physical fractions or soil were observed. CONCLUSIONS: Although the bioavailable element portions in the PM samples were lower compared to plants, the bioavailable element contents in foliar PM-amended plant leaves exceeded the control and soil PM amendment levels, even after biomass washing.

• MeSH
• arsen analýza   MeSH
• Beta vulgaris chemie   MeSH
• biologická dostupnost MeSH
• biomasa MeSH
• dieta MeSH
• kadmium analýza   MeSH
• kořeny rostlin MeSH
• látky znečišťující půdu analýza   MeSH
• látky znečišťující vzduch analýza   MeSH
• lidé MeSH
• listy rostlin * MeSH
• pevné částice analýza   MeSH
• půda chemie   MeSH
• salát (hlávkový) chemie   MeSH
• stopové prvky analýza   toxicita   MeSH
• tenké střevo MeSH
• žaludek MeSH
• železo analýza   MeSH
• zinek analýza   MeSH
• Check Tag
• lidé MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH