30 research outputs found

    Modellprojekt in der Berufsbildung fĂŒr nachhaltige Entwicklung

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    Das Forschungsvorhaben „Verwertung von GemĂŒse- und GrĂŒnschnittabfĂ€llen zur Herstellung von Pflanzenkohlesubstraten fĂŒr ein klimafreundliches GĂ€rtnern - Modellprojekt in der Berufsbildung fĂŒr nachhaltige Entwicklung“ untersuchte die Schließung regionaler StoffkreislĂ€ufe mittels Pflanzenkohletechnologie und schuf Modellprojekte, um berufliche und schulische Aus- und Weiterbildung zu fördern und anschaulich erlebbar zu machen. Die Pflanzenkohletechnologie wird auf internationaler Ebene vermehrt als eine Option zur RĂŒckfĂŒhrung von Kohlendioxid aus der AtmosphĂ€re (carbon dioxide removal; kurz CDR Technologie) diskutiert. Pflanzenkohle bezeichnet das Endprodukt der Karbonisierung von Biomasse durch Pyrolyse bei einer Temperatur zwischen 350 und 900 °C. Bei der Karbonisierung wird im Gegensatz zur Verbrennung oder natĂŒrlichen Verrottung nur etwa 50 - 60 % des in der Biomasse gespeicherten Kohlenstoffs wieder an die AtmosphĂ€re abgegeben. Die Prozesstemperaturen bestimmen dabei maßgeblich die Eigenschaften, wie z. B. Kohlenstoffgehalt und StabilitĂ€t. Die hohe StabilitĂ€t und damit die langfristige Festlegung von Kohlenstoff in der Pflanzenkohle und deren stoffliche Anwendung könnte eine signifikante Rolle bei der Verlangsamung des Anstiegs der atmosphĂ€rischen CO2-Konzentrationen spielen. Durch den Aufbau bzw. die Nutzung von Kompostieranlagen mit Pflanzenkohle, entstanden modellhafte Lernorte am Umweltbildungszentrum Berlin, im Gutsgarten Hellersdorf und im Botanischen Garten Berlin-Dahlem, an denen zugleich lokale StoffkreislĂ€ufe geschlossen wurden. Die Kompostierung mit Pflanzenkohle wurde an den einzelnen Modellstandorten wissenschaftlich begleitet und die Umweltwirkung mittels Klimabilanz ermittelt und mit der energetischen Nutzung durch VergĂ€rung/Biogas bzw. Verbrennung verglichen. FĂŒr die berufliche Aus- und Weiterbildung zum Thema „Stoffkreisschließung mit Pflanzenkohle“ wurden 25 Bildungsmodule entwickelt. Die Module wurden an den Lernorten in insgesamt 11 vier- bis fĂŒnfstĂŒndigen Workshops mindesten zweifach mit insgesamt 200 Auszubildenden und UmschĂŒlerInnen positiv evaluiert. Entstanden ist ein Bildungsmaterial „Pflanzenkohle“ fĂŒr die berufliche - aber auch schulische - Bildung, in dem das Thema Pflanzenkohle und ihre Anwendung im gĂ€rtnerischen und landwirtschaftlichen Bereich aufbereitet wurde. In den Blick gelangt die gegenwĂ€rtige Herstellung von Pflanzenkohle und Pflanzenkohlesubstraten durch die Kompostierung und ihre gĂ€rtnerischen Anwendungen. Die Pflanzenkohle-Technologie wird im Kontext des Klima- und Bodenschutzes und der nachhaltigen Ressourcennutzung verortet und als Negative Emissionstechnologie eingefĂŒhrt. DarĂŒber hinaus entstand ein weiteres Bildungsmaterial „Boden entdecken“ fĂŒr die 5. und 6. Klasse, dass das Thema Pflanzenkohle und Kompostierung in einen Projekttag zum Boden einbettet. In 12 Lernstationen, beschreiben SchĂŒler*innen den Boden, entdecken seine Lebewesen, erforschen seine Entstehung, starten einen Kompostversuch und sammeln Ideen fĂŒr den Schutz des Bodens

    Long-term effects of sulfidized silver nanoparticles in sewage sludge on soil microflora

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    The use of silver nanoparticles (AgNPs) in consumer products such as textiles leads to their discharge into wastewater and consequently to a transfer of the AgNPs to soil ecosystems via biosolids used as fertilizer. In urban wastewater systems (e.g., sewer, wastewater treatment plant [WWTP], anaerobic digesters) AgNPs are efficiently converted into sparingly soluble silver sulfides (Ag2S), mitigating the toxicity of the AgNPs. However, long-term studies on the bioavailability and effects of sulfidized AgNPs on soil microorganisms are lacking. Thus we investigated the bioavailability and long-term effects of AgNPs (spiked in a laboratory WWTP) on soil microorganisms. Before mixing the biosolids into soil, the sludges were either anaerobically digested or directly dewatered. The effects on the ammonium oxidation process were investigated over 140 d. Transmission electron microscopy (TEM) suggested an almost complete sulfidation of the AgNPs analyzed in all biosolid samples and in soil, with Ag2S predominantly detected in long-term incubation experiments. However, despite the sulfidation of the AgNPs, soil ammonium oxidation was significantly inhibited, and the degree of inhibition was independent of the sludge treatment. The results revealed that AgNPs sulfidized under environmentally relevant conditions were still bioavailable to soil microorganisms. Consequently, Ag2S may exhibit toxic effects over the long term rather than the short term

    Endbericht des Forschungsprojektes RuBuS

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    Der vorliegende Bericht behandelt die Ergebnisse des Forschungsprojektes RUBUS, welches im Zeitraum November 2013 bis November 2015 von der Freien UniversitĂ€t Berlin durchgefĂŒhrt wurde. Gegenstand des Projektes ist die Untersuchung der aktuellen Belastungssituation und der Dynamik der Sedimente in der Rummelsburger Bucht als Teil der urbanen Spree in Berlin. Das Projekt hat die KlĂ€rung der rĂ€umlichen Verteilung, Quantifizierung und Bewertung der Schadstoffbelastung in den Sedimenten der Rummelsburger Bucht zum Ziel. Es soll vor diesem Hintergrund die Ausbildung einer unbelasteten Sedimentauflage geprĂŒft werden, um damit auch der Frage nachzugehen, ob es möglicherweise zu einer Remobilisierung von schadstoffbelasteten Sedimenten kommt. Um diese Hypothese zu untersuchen wird ein indirekter Messansatz gewĂ€hlt, der sowohl die Erfassung der Randbedingungen als auch den qualitativen und quantitativen Nachweis einer Sedimentremobilisierung berĂŒcksichtigt. Da die Prozesse als solche nur schwer messbar sind, zielt dieser Ansatz darauf ab, entsprechende Leitindikatoren zu wĂ€hlen, anhand derer Mobilisierungsmechanismen und Ursachen aufgezeigt werden können. Die Erfassung der Schadstoffe (Schwermetalle, organische Verbindungen) erfolgt systematisch an 5 Schichten der obersten 15 cm des GewĂ€ssersedimentes und ĂŒber die Erfassung von akkumuliertem Material in Sedimentfallen. Die Beprobungen und kontinuierlichen Messungen werden an 15 ĂŒber den gesamten Wasserkörper rasterförmig ausgelegten Bohr- bzw. Messpunkten durchgefĂŒhrt. Zur Bemessung des potenziellen Risikos wird fĂŒr die Feststoffphase der Consensus 2 - Wert der SedimentqualitĂ€tsrichtlinien nach de DECKERE et al. (2011) zugrunde gelegt und durch Elutionsversuche sowie ökotoxikologische Tests ergĂ€nzt. Die Laborergebnisse zeigen, dass an allen Standorten und in annĂ€hernd allen erfassten Sedimentschichten weitestgehend sĂ€mtliche untersuchten Elemente und Verbindungen in zum Teil erheblichen Konzentrationen nachgewiesen werden können. Die Konzentrationen variieren sowohl in der FlĂ€che als auch mit der Tiefe der Sedimentschichten. Die Analysen und statistischen Tests weisen das nordwestliche Untersuchungsgebiet als am stĂ€rksten belastet aus. Ungeachtet dieser rĂ€umlichen Variationen zeigen die Ergebnisse, dass in der Rummelsburger Bucht eine durchgĂ€ngige Belastung der oberen 15 cm Sedimentschicht vorliegt. Eine flĂ€chendeckende Belastung kann auch fĂŒr die beprobten Sedimentfallen nachgewiesen werden. Im Vergleich zum Referenzstandort in der Spree zeigt sich, dass die Rummelsburger Bucht sowohl hinsichtlich der Sedimentkerne als auch hinsichtlich der Sedimentfallen eine durchgĂ€ngig höhere Belastung aufweist. Effektbasierte SQG werden in den meisten FĂ€llen ĂŒberschritten. Eine Untersuchung aquatischer Makrozoen durch die Bundesanstalt fĂŒr GewĂ€sserkunde zeigt zudem, dass die Artenvielfalt gering ist und sich das Vorkommen auf tolerante, euryöke Arten mit geringen AnsprĂŒchen an die GewĂ€sser- und SedimentqualitĂ€t beschrĂ€nkt. FĂŒr den hohen gemessenen Sedimentumsatz ist vor allem die Remobilisierung von Sedimenten innerhalb der Bucht verantwortlich. Die stark belasteten, sehr schluffhaltigen Sedimente werden ĂŒber eine permanente Strömung diffus ĂŒber die gesamte SeeflĂ€che verteilt. Als bisherige Ursache fĂŒr den hohen Sedimentumsatz können u.a. meteorologische Bedingungen und der Bootsverkehr identifiziert werden. Die mechanische Mobilisierbarkeit von feststoffgebundenen Schwermetallen und zinnorganischen Verbindungen ist unter den vorherrschenden Bedingungen in der Rummelsburger Bucht gering. Die chemisch-physikalischen Randbedingungen des Untersuchungsgebiets sind im Jahreszyklus nur geringen Schwankungen unterworfen, was der weiteren Fixierung der Schwermetalle entgegenkommt. MKW und PAK werden hingegen durch die Elution in höheren Konzentrationen freigesetzt, insbesondere aus den Schwebstoffen. Im Fall der PAK werden in den meisten Proben die ZHK-UQN bzw. die JD-UQN der EuropĂ€ischen Wasserrahmenrichtlinie fĂŒr die Wasserphase ĂŒberschritten. Keiner der biologischen Tests zeigt eine gefĂ€hrliche Belastung an. Es werden jedoch mit dem Sedimentkontakt- und dem Leuchtbakterientest bei mehreren Proben kritische Belastungen ermittelt. Von den PAK geht offensichtlich keine GefĂ€hrdung fĂŒr die Testorganismen Vibrio fischeri (Leuchtbakterien) und Lemna minor (Wasserlinsen) aus. Die Wasserlinsen reagieren durchgehend wenig sensitiv auf die Inhaltsstoffe der Eluate. Es ist anzunehmen, dass die signifikant höhere MKW-Freisetzung aus den Schwebstoffen (im Gegensatz zu den Sedimenten) die toxische Wirkung im Leuchtbakterientest verursacht. Der Sedimentkontakttest weist bei einer den Schadstoffgehalten nach relativ unbelasteten Probe einen toxischen Effekt nach. Die hohen Schwermetallgehalte in den Sedimenten haben keine Wirkung auf die Bakterien des Sedimentkontakttests, was darauf hindeutet, dass sie nicht in bioverfĂŒgbarer Form vorliegen. Die Schwermetalle scheinen unter stabilen Bedingungen gebunden vorzuliegen. Die PAK und MKW zeigen eine deutlich höhere Dynamik in der SchadstoffmobilitĂ€t. Die Rummelsburger Bucht stellt selbst im internationalen Kontext eine Besonderheit hinsichtlich der hohen Belastung mit organischen Schadstoffverbindungen und Schwermetallen dar und zeigt, dass die industriellen FingerabdrĂŒcke der Gesellschaft ĂŒber Ă€ußerst lange ZeitrĂ€ume erhalten bleiben und dies eine Herausforderung fĂŒr Politik und Planung darstellt. Die Untersuchungsergebnisse zeigen aber auch, dass die Rummelsburger Bucht einer ausreichend großen Dynamik unterliegt, welche zu einer (Re-) Mobilisierung dieser hochbelasteten Sedimente fĂŒhren kann. Die Sedimente fungieren als langfristige potenzielle Schadstoffquelle fĂŒr den Wasserkörper und damit auch fĂŒr die Spree.The present report covers the results of the research project RuBuS, realised by the Freie UniversitĂ€t Berlin between November 2013 and 2015. The investigated water body “Rummelsburger Bucht” is a former anabranch of the Spree River located in the centre of Berlin. Covering an area of more than 45 ha, it is only at the upstream side connected to the main river course. For almost a century, untreated industrial and municipal wastewater was discharged into this river branch. Consequently, the quality of both the water and the sediments decreased dramatically over that period. In order to address this problem, the project “RuBuS” (co-financed by the Berlin State Government and the European Funds for Social and Regional Development) was established for the above mentioned period. To perform any risk assessment, the investigation should provide an improved knowledge and a better understanding about the type and spatio-temporal pattern of sediment contamination and dynamics. To detect the spatial distribution of pollutants in the sediment, over 200 sediment samplings were carried out via drill cores from 16 locations. The upper 15 cm of each drill core was systematically divided into 5 layers (each of 3 cm) for separate examination. The investigation of sedimentation and remobilisation rates was accomplished by installing 18 sediment traps, which collected deposits over more than a year. The presence of selected heavy metals and organic pollutants in the sediments was determined for every position and layer of the drill cores, as well as for all sediment traps. Detection of changes in boundary conditions, influencing the spatial and temporal distribution of sedimentation and resuspension, was accomplished by placing devices within the water body and taking different mobile measurements. At all sampling locations, flow conditions were recorded every week over the whole water column with a vessel-mounted ADCP (Acoustic Doppler Current Profiler). Water quality parameters like oxygen, turbidity, chlorophyll-(a) and temperature were also measured weekly with a mobile multiparameter sensor at all stations in 50 cm steps. In addition, these parameters were continuously recorded every 10 minutes with stationary sensors at different water depths (1, 2 and 3 m) from the beginning of the monitoring. For mobile measurements the probe YSI 6600 V2 was used, whereas permanent recording was done with Cyclops-7 and MiniDot devices from PME. A weather station was set up on the shore side to determine wind conditions, precipitation, temperature and solar radiation, concerning the external impacts on water currents, turbulences and algae-bloom. The scope of the investigation included the determination of the total content of inorganic (Hg, Cd, Cr, Pb, Ni, Cu, Zn) and organic compounds (polycyclic aromatic hydrocarbons (PAH), total petroleum hydrocarbons (TPH), selected nitro-compounds, selected organotin compounds and polychlorinated biphenyls (PCB, AOX and EOX) in the sediment and suspended matter. The relevant particle size for the investigation of samples for heavy metals was < 63 ÎŒm and for the organic components < 2 mm. The compounds were detected by ICP-OES, ICP-MS and AAS analyses. Grain size distributions weredetermined using laser diffractometry and sieving. An elemental analyser was used to determine the presence of carbon and nitrogen in the samples. The release of soluble components upon contact with water is considered one of the main mechanisms leading to a potential hazard to the environment. The research into soluble and easily mobile sediment-bounded pollutants is based upon a 24 hour batch test. In addition, certain toxic effects of the sediments were determined by ecotoxicological test methods. Three species were chosen as relevant test organisms: Vibrio fischeri for the luminescent bacteria test, Lemna minor for the Duckweed growth inhibition test and Arthrobacter globiformis for the sediment contact test. In addition, the thresholds of the sediment quality guidelines, published by de Deckere et al. (2011), were used to assess the solid contents. The study demonstrated that so far the concentration of organic and inorganic pollutants in the sediments has remained very high. The total contents of the PAHs and all heavy metals exceeded the effect-based threshold values according to de Deckere et al. (2011). The results were compared to the “consensus 2” thresholds to identify the measured concentrations, which have surpassed the limits and now giving rise to concern regarding toxicity. The only exception among the heavy metals was mercury. With respect to organic pollution the reference point in the Spree River, which is not very far away from the sheet pile wall, showed concentrations below the threshold value. In contrast, the reference point disclosed pollution by heavy metals except for cadmium and mercury concentrations, which were below the threshold. However, the load of heavy metals at the reference point was lower than the one found in the bay. A different spatial distribution of the organic contamination was observed for the sediments of the “Rummelsburger Bucht”. In terms of contamination with PAHs, Cd and Pb, areas with different loads could be defined, this was statistically proven with a significant difference greater than 99%. The less contaminated area was situated between the sheet pile wall and the centre of the bay. Higher loads (sampling sites 10-15) were found from the centre of the water body to the north-western shore. However, the sediments in the traps showed a homogeneous distribution of the measured pollutants. It was also found, that the level of contamination commonly increased with sediment depth, except at the sampling sites right in the centre of the bay, which revealed no clear tendency to increase or decrease depending on the depth. With regard to the level of the European Environmental Quality Standards (EQS), the results of the 24 hour batch test indicated a low mobility of the heavy metals, organotin compounds and Benzo(a)pyrene. By contrast, other PAH compounds exceeded in several eluates the annual average maximum concentration permitted by the EQS. The results of the Luminescent bacteria test demonstrated for the eluates of sediment cores, that all samples are not or harmless polluted (non- or low toxic effect). However, with the exception of two samples, all of the eluates of suspended particles were critically polluted, they showed a moderate or increased toxic effect. The recorded high turnover rates of sediments were most likely caused by a remobilisation of local sources within the “Rummelsburger Bucht”. These highly contaminated and silty sediments can be evenly distributed over the whole area of the water body due to very slow but constant currents with changing directions. Up to now, specific meteorological boundary conditions and motorboat-traffic have been identified as some of the main reasons for the remobilisation and local transport of the sediments, as well as external sediment sources could be neglected. The research project “RuBuS” provides a detailed insight into this water body. It gives a better understanding how changes in boundary conditions affect the spatial and temporal distribution of sedimentation and the resuspension of sediments. The study demonstrates, that so far the concentration of organic and inorganic pollutants in the sediments has remained on an exceptionally high level. The “Rummelsburger Bucht” can be considered as a case study about spatio-temporal pattern of sediment contamination and dynamics of the Spree River and about areas of conflict presented by highly stressed urban water bodies. A high pressure on demands of local residents for recreational and commercial use of the “Rummelsburger Bucht” needs to improve the environmental situation by a targeted and affordable management plan

    Superior Ventriculo-Arterial Coupling with Decellularized Allografts Compared with Conventional Prostheses

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    Background To date, no experimental or clinical study provides detailed analysis of vascular impedance changes after total aortic arch replacement. This study investigated ventriculoarterial coupling and vascular impedance after replacement of the aortic arch with conventional prostheses vs. decellularized allografts. Methods After preparing decellularized aortic arch allografts, their mechanical, histological and biochemical properties were evaluated and compared to native aortic arches and conventional prostheses in vitro. In open-chest dogs, total aortic arch replacement was performed with conventional prostheses and compared to decellularized allografts (n = 5/group). Aortic flow and pressure were recorded continuously, left ventricular pressure-volume relations were measured by using a pressure- conductance catheter. From the hemodynamic variables end-systolic elastance (Ees), arterial elastance (Ea) and ventriculoarterial coupling were calculated. Characteristic impedance (Z) was assessed by Fourier analysis. Results While Ees did not differ between the groups and over time (4.1±1.19 vs. 4.58±1.39 mmHg/mL and 3.21±0.97 vs. 3.96±1.16 mmHg/mL), Ea showed a higher increase in the prosthesis group (4.01±0.67 vs. 6.18±0.20 mmHg/mL, P<0.05) in comparison to decellularized allografts (5.03±0.35 vs. 5.99±1.09 mmHg/mL). This led to impaired ventriculoarterial coupling in the prosthesis group, while it remained unchanged in the allograft group (62.5±50.9 vs. 3.9±23.4%). Z showed a strong increasing tendency in the prosthesis group and it was markedly higher after replacement when compared to decellularized allografts (44.6±8.3dyn·sec·cm−5 vs. 32.4±2.0dyn·sec·cm−5, P<0.05). Conclusions Total aortic arch replacement leads to contractility-afterload mismatch by means of increased impedance and invert ventriculoarterial coupling ratio after implantation of conventional prostheses. Implantation of decellularized allografts preserves vascular impedance thereby improving ventriculoarterial mechanoenergetics after aortic arch replacement

    Total Aortic Arch Replacement: Superior Ventriculo-Arterial Coupling with Decellularized Allografts Compared with Conventional Prostheses.

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    BACKGROUND: To date, no experimental or clinical study provides detailed analysis of vascular impedance changes after total aortic arch replacement. This study investigated ventriculoarterial coupling and vascular impedance after replacement of the aortic arch with conventional prostheses vs. decellularized allografts. METHODS: After preparing decellularized aortic arch allografts, their mechanical, histological and biochemical properties were evaluated and compared to native aortic arches and conventional prostheses in vitro. In open-chest dogs, total aortic arch replacement was performed with conventional prostheses and compared to decellularized allografts (n = 5/group). Aortic flow and pressure were recorded continuously, left ventricular pressure-volume relations were measured by using a pressure-conductance catheter. From the hemodynamic variables end-systolic elastance (Ees), arterial elastance (Ea) and ventriculoarterial coupling were calculated. Characteristic impedance (Z) was assessed by Fourier analysis. RESULTS: While Ees did not differ between the groups and over time (4.1+/-1.19 vs. 4.58+/-1.39 mmHg/mL and 3.21+/-0.97 vs. 3.96+/-1.16 mmHg/mL), Ea showed a higher increase in the prosthesis group (4.01+/-0.67 vs. 6.18+/-0.20 mmHg/mL, P<0.05) in comparison to decellularized allografts (5.03+/-0.35 vs. 5.99+/-1.09 mmHg/mL). This led to impaired ventriculoarterial coupling in the prosthesis group, while it remained unchanged in the allograft group (62.5+/-50.9 vs. 3.9+/-23.4%). Z showed a strong increasing tendency in the prosthesis group and it was markedly higher after replacement when compared to decellularized allografts (44.6+/-8.3dyn.sec.cm-5 vs. 32.4+/-2.0dyn.sec.cm-5, P<0.05). CONCLUSIONS: Total aortic arch replacement leads to contractility-afterload mismatch by means of increased impedance and invert ventriculoarterial coupling ratio after implantation of conventional prostheses. Implantation of decellularized allografts preserves vascular impedance thereby improving ventriculoarterial mechanoenergetics after aortic arch replacement

    Scrapie Agent (Strain 263K) Can Transmit Disease via the Oral Route after Persistence in Soil over Years

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    The persistence of infectious biomolecules in soil constitutes a substantial challenge. This holds particularly true with respect to prions, the causative agents of transmissible spongiform encephalopathies (TSEs) such as scrapie, bovine spongiform encephalopathy (BSE), or chronic wasting disease (CWD). Various studies have indicated that prions are able to persist in soil for years without losing their pathogenic activity. Dissemination of prions into the environment can occur from several sources, e.g., infectious placenta or amniotic fluid of sheep. Furthermore, environmental contamination by saliva, excrements or non-sterilized agricultural organic fertilizer is conceivable. Natural transmission of scrapie in the field seems to occur via the alimentary tract in the majority of cases, and scrapie-free sheep flocks can become infected on pastures where outbreaks of scrapie had been observed before. These findings point to a sustained contagion in the environment, and notably the soil. By using outdoor lysimeters, we simulated a contamination of standard soil with hamster-adapted 263K scrapie prions, and analyzed the presence and biological activity of the soil-associated PrPSc and infectivity by Western blotting and hamster bioassay, respectively. Our results showed that 263K scrapie agent can persist in soil at least over 29 months. Strikingly, not only the contaminated soil itself retained high levels of infectivity, as evidenced by oral administration to Syrian hamsters, but also feeding of aqueous soil extracts was able to induce disease in the reporter animals. We could also demonstrate that PrPSc in soil, extracted after 21 months, provides a catalytically active seed in the protein misfolding cyclic amplification (PMCA) reaction. PMCA opens therefore a perspective for considerably improving the detectability of prions in soil samples from the field

    Western blot detection of PrP27-30 extracted from prion-contaminated soil after 21 months (M21) and respective surrounding samples.

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    <p>M21: contaminated soil sample inside the gauze bag; lane 1: soil sample collected outside of the steel cage; lane 2: soil sample collected directly over the gauze bag; lane 3: analysis of the empty gauze bag; lane 4: soil sample collected underneath the steel cage; lane 5: soil sample collected directly next to the gauze bag; lane 6: roots collected next to the gauze bag; lane 7: soil sample collected underneath the gauze bag; lane 8: non-contaminated soil. Arrow head at lane 3 indicates a faint PrP27-30 signal, resulting from residual soil particles that remained attached to the gauze bag.</p
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