Global fine-resolution data on springtail abundance and community structure

Springtails (Collembola) inhabit soils from the Arctic to the Antarctic and comprise an estimated ~32% of all terrestrial arthropods on Earth. Here, we present a global, spatially-explicit database on springtail communities that includes 249,912 occurrences from 44,999 samples and 2,990 sites. These data are mainly raw sample-level records at the species level collected predominantly from private archives of the authors that were quality-controlled and taxonomically-standardised. Despite covering all continents, most of the sample-level data come from the European continent (82.5% of all samples) and represent four habitats: woodlands (57.4%), grasslands (14.0%), agrosystems (13.7%) and scrublands (9.0%). We included sampling by soil layers, and across seasons and years, representing temporal and spatial within-site variation in springtail communities. We also provided data use and sharing guidelines and R code to facilitate the use of the database by other researchers. This data paper describes a static version of the database at the publication date, but the database will be further expanded to include underrepresented regions and linked with trait data.

Biotic and Abiotic Interactions in Freshwater Mesocosms Determine Fate and Toxicity of CuO Nanoparticles

Transformation, dissolution, and sorption of copper oxide nanoparticles (CuO-NP) play an important role in freshwater ecosystems. We present the first mesocosm experiment on the fate of CuO-NP and the dynamics of the zooplankton community over a period of 12 months. Increasingly low (0.08-0.28 mg Cu L-1) and high (0.99-2.99 mg Cu L-1) concentrations of CuO-NP and CuSO4 (0.10-0.34 mg Cu L-1) were tested in a multiple dosing scenario. At the high applied concentration (CuO-NP_H) CuO-NP aggregated and sank onto the sediment layer, where we recovered 63% of Cu applied. For the low concentration (CuO-NP_L) only 41% of applied copper could be recovered in the sediment. In the water column, the percentage of initially applied Cu recovered was on average 3-fold higher for CuO-NP_L than for CuO-NP_H. Zooplankton abundance was substantially compromised in the treatments CuSO4 (p < 0.001) and CuO-NP_L (p < 0.001). Community analysis indicated that Cladocera were most affected (bk = -0.49), followed by Nematocera (bk = -0.32). The abundance of Cladocera over time and of Dixidae in summer was significantly reduced in the treatment CuO-NP_L (p < 0.001; p < 0.05) compared to the Control. Our results indicate a higher potential for negative impacts on the freshwater community when lower concentrations of CuO-NP (<0.1 mg Cu L-1) enter the ecosystem.

Ångstrom-Depth Resolution with Chemical Specificity at the Liquid-Vapor Interface

The determination of depth profiles across interfaces is of primary importance in many scientific and technological areas. Photoemission spectroscopy is in principle well suited for this purpose, yet a quantitative implementation for investigations of liquid-vapor interfaces is hindered by the lack of understanding of electron-scattering processes in liquids. Previous studies have shown, however, that core-level photoelectron angular distributions (PADs) are altered by depth-dependent elastic electron scattering and can, thus, reveal information on the depth distribution of species across the interface. Here, we explore this concept further and show that the experimental anisotropy parameter characterizing the PAD scales linearly with the average distance of atoms along the surface normal obtained by molecular dynamics simulations. This behavior can be accounted for in the low-collision-number regime. We also show that results for different atomic species can be compared on the same length scale. We demonstrate that atoms separated by about 1 Å along the surface normal can be clearly distinguished with this method, achieving excellent depth resolution.

Improving Membrane Filtration for Copper Speciation: Optimal Salt Pretreatments of Polyethersulfone Membranes to Prevent Analyte Retention

Membrane filtration has been increasingly used to separate dissolved metal ions from dispersed particles, commonly using ultrafiltration membranes, for example, polyethersulfone (PES) membranes with a molecular weight cut-off of 3 kDa. The disadvantage of this technique is an undesired retention of ions, resulting from Coulomb interactions with sulfonic acid groups of the membrane. Therefore, such a membrane acts similar to a cation exchanger column. We solved this drawback by a pretreatment of the PES membrane by other cations. Using CuSO₄ as a model compound, we compared the effectiveness of five cations using their salt solutions (Ca²⁺, Mg²⁺, Fe²⁺, Ag⁺, Ba²⁺) as pretreatment agents and identified the most effective pretreatment component for a high recovery of copper ions. After membrane filtration without pretreatment, only 52 ± 10%, 64 ± 5%, 75 ± 8%, and 89 ± 7% of nominal Cu concentrations were obtained using initial concentrations of 0.2, 0.5, 1.0, and 4.0 mg L^-1, respectively. The efficiency of the investigated cations increased in the order Fe < Ag < Mg < Ca < Ba. Furthermore, we analyzed the most efficient concentration of the pretreatment agent. The best performance was achieved using 0.1 mol L^-1 CaCl₂ which increased copper recovery to slightly below 100%, even at the lowest tested Cu concentration (recovery 93 ± 10% at 0.2 mg L^-1). In the environmentally relevant Cu concentration range of 0.2 mg L^-1, 0.1 mol L^-1 BaCl₂ was identified as the most efficient pretreatment (103 ± 11%).

Clay Types Modulate the Toxicity of Low Concentrated Copper Oxide Nanoparticles Toward Springtails in Artificial Test Soils

Copper oxide nanoparticles (CuO-NPs) can be applied as an efficient alternative to conventional Cu in agriculture. Negative effects of CuO-NPs on soil organisms were found, but only in clay-rich loamy soils. It is hypothesized that clay-NP interactions are the origin of the observed toxic effects. In the present study, artificial Organisation for Economic Co-operation and Development soils containing 30% of kaolin or montmorillonite as clay type were spiked with 1-32 mg Cu/kg of uncoated CuO-NPs or CuCl₂ . We performed 28-day reproduction tests with springtails of the species Folsomia candida and recorded the survival, reproduction, dry weight, and Cu content of adults. In a second experiment, molting frequency and the Cu content of exuviae, as well as the biochemical endpoints metallothionein and catalase (CAT) in springtails, were investigated. In the reproduction assay, negative effects on all endpoints were observed, but only in soils containing montmorillonite and mostly for CuO-NPs. For the biochemical endpoints and Cu content of exuviae, effects were clearly distinct between Cu forms in montmorillonite soil, but a significant reduction compared to the control was only found for CAT activity. Therefore, the reduced CAT activity in CuO-NP-montmorillonite soil might be responsible for the observed toxicity, potentially resulting from reactive oxygen species formation overloading the antioxidant system. This process seems to be highly concentration-dependent, because all endpoints investigated in reproduction and biochemical assays of CuO-NP-montmorillonite treatments showed a nonlinear dose-response relationship and were constantly reduced by approximately 40% at a field-realistic concentration of 3 mg/kg, but not at 32 mg/kg. The results underline that clay-CuO-NP interactions are crucial for their toxic behavior, especially at low, field-realistic concentrations, which should be considered for risk assessment of CuO-NPs. Environ Toxicol Chem 2022;41:2454-2465. © 2022 The Authors. Environmental Toxicology and Chemistry published by Wiley Periodicals LLC on behalf of SETAC.

Potential of the Red Alga Dixoniella grisea for the Production of Additives for Lubricants

There is an increasing interest in algae-based raw materials for medical, cosmetic or nutraceutical applications. Additionally, the high diversity of physicochemical properties of the different algal metabolites proposes these substances from microalgae as possible additives in the chemical industry. Among the wide range of natural products from red microalgae, research has mainly focused on extracellular polymers for additive use, while this study also considers the cellular components. The aim of the present study is to analytically characterize the extra- and intracellular molecular composition from the red microalga Dixoniella grisea and to evaluate its potential for being used in the tribological industry. D. grisea samples, fractionated into extracellular polymers (EPS), cells and medium, were examined for their molecular composition. This alga produces a highly viscous polymer, mainly composed of polysaccharides and proteins, being secreted into the culture medium. The EPS and biomass significantly differed in their molecular composition, indicating that they might be used for different bio-additive products. We also show that polysaccharides and proteins were the major chemical compounds in EPS, whereas the content of lipids depended on the separation protocol and the resulting product. Still, they did not represent a major group and were thus classified as a potential valuable side-product. Lyophilized algal fractions obtained from D. grisea were found to be not toxic when EPS were not included. Upon implementation of EPS as a commercial product, further assessment on the environmental toxicity to enchytraeids and other soil organisms is required. Our results provide a possible direction for developing a process to gain an environmentally friendly bio-additive for application in the tribological industry based on a biorefinery approach.

Use of deep learning for structural analysis of computer tomography images of soil samples

Soil samples from several European countries were scanned using medical computer tomography (CT) device and are now available as CT images. The analysis of these samples was carried out using deep learning methods. For this purpose, a VGG16 network was trained with the CT images (X). For the annotation (y) a new method for automated annotation, 'surrogate' learning, was introduced. The generated neural networks (NNs) were subjected to a detailed analysis. Among other things, transfer learning was used to check whether the NN can also be trained to other y-values. Visually, the NN was verified using a gradient-based class activation mapping (grad-CAM) algorithm. These analyses showed that the NN was able to generalize, i.e. to capture the spatial structure of the soil sample. Possible applications of the models are discussed.

Soil properties can evoke toxicity of copper oxide nanoparticles towards springtails at low concentrations

Copper oxide nanoparticles (CuO-NP) are used as an efficient alternative to conventional Cu in agriculture and might end up in soils. They show a high toxicity towards cells and microorganisms, but only low toxicity towards soil invertebrates. However, most existing soil ecotoxicological studies were conducted in a sandy reference soil and at test concentrations ≥100 mg Cu/kg soil. Therefore, there is a knowledge gap concerning the effect of soil texture on the toxicity of CuO-NP at lower, more realistic test concentrations. In our study, a sandy reference soil and three loamy soils were spiked with CuO-NP at up to four concentrations, ranging from 5 to 158 mg Cu/kg. We investigated 28-day reproduction as well as weight and Cu content after 14-day bioaccumulation and subsequent 14-day elimination for the springtail Folsomia candida. For the first time we analysed the size distribution of CuO-NP in aqueous test soil extracts by single particle-ICP-MS which revealed that the diameter of CuO-NP significantly increased with increasing concentration, but did not vary between test soils. Negative effects on reproduction were only observed in loamy soils, most pronounced in a loamy-acidic soil (-61%), and they were always strongest at the lowest test concentration. The observed effects were much stronger than reported by other studies performed with sandy soils and higher CuO-NP concentrations. In the same soil and concentration, a moderate impact on growth (-28%) was observed, while Cu elimination from springtails was inhibited. Rather than Cu body concentration, the diameter of the CuO-NP taken up, as well as NP-clay interactions might play a crucial role regarding their toxicity. Our study reports for the first time toxic effects of CuO-NP towards a soil invertebrate at a low, realistic concentration range. The results strongly suggest including lower test concentrations and a range of soil types in nanotoxicity testing.

Sulfidation of sea urchin-like zinc oxide nanospheres: Kinetics, mechanisms, and impacts on growth of Escherichia coli

Nanoscale zinc oxide (n-ZnO) with different morphology and sizes has been used in personal care products due to their antibacterial properties, resulting in discharge of n-ZnO into the environment with potential toxic effect to ecological systems. Sulfidation is one of pathways of transformation of n-ZnO, but a very limited information on the conversion of n-ZnO under sulfidic environment with special morphology such as sea urchin-like zinc oxide nanospheres (ZnO-NSs) is available to know the potential environmental risks of n-ZnO. Herein, sea urchin-like ZnO-NSs with an average size of 78 nm were synthesized and adopted as the model n-ZnO of special morphology. The ZnO-NPs at average sizes of 71 nm (ZnO-NPs-71), 48 nm (ZnO-NPs-48), and 17 nm (ZnO-NPs-17) nm were used to examine possible differences in the sulfidation between the sea urchin-like ZnO-NSs and ZnO-NPs. A new analytical method selectively dissolving ZnO over ZnS in partially sulfidized n-ZnO was developed and applied to understand the kinetics of n-ZnO sulfidation. The sulfidation rate constant (k_s) of sea urchin-like ZnO-NSs was 2.9 × 10^-3 h^-1, comparable to that of ZnO-NPs-71 (4.1 × 10^-3 h^-1), but much lower than those of ZnO-NPs-48 (20.1 × 10^-3 h^-1) and ZnO-NPs-17 (67.8 × 10^-3 h^-1). This might be attributed to the differences in the specific surface area; k_s positively correlated with the specific surface area (R² = 0.97). Natural organic matter (NOM) decreased dissolution and sulfidation of the sea urchin-like ZnO-NSs. Aggregate ZnS nanocrystals instead of the original sea urchin-like ZnO-NSs were observed. We proposed that sea urchin-like ZnO-NSs were transformed to ZnS through a dissolution-precipitation pathway, consistent with the sulfidation pathway of ZnO-NPs. Sulfidation drastically reduced toxicity of sea urchin-like ZnO-NSs to Escherichia coli due to negligible dissolution of ZnS nanocrystals. These results greatly improved our understanding of the transformation and potential risks of n-ZnO with special morphology.

Assessing the Impacts of Cu(OH)2 Nanopesticide and Ionic Copper on the Soil Enzyme Activity and Bacterial Community

Nanopesticides are being introduced in agriculture, and the associated environmental risks and benefits must be carefully assessed before their widespread agricultural applications. We investigated the impacts of a commercial Cu(OH)₂ nanopesticide formulation (NPF) at different agricultural application doses (e.g., 0.5, 5, and 50 mg of Cu kg^-1) on enzyme activities and bacterial communities of loamy soil (organic matter content of 3.61%) over 21 days. Results were compared to its ionic analogue (i.e., CuSO₄) and nano-Cu(OH)₂, including both the commercial unformulated active ingredient of NPF (AI-NPF) and synthesized Cu(OH)₂ nanorods (NR). There were negligible changes in the activity of acid phosphatase, regardless of exposure dose, whereas significant (p < 0.05) variations in activities of invertase, urease, and catalase were observed at a dose of 5 mg kg^-1 or higher. Invertase activity decreased with an increasing bioavailable Cu concentration in soil under various treatments. In comparison to CuSO₄, both Cu(OH)₂ nanopesticide (i.e., NPF) and nano-Cu(OH)₂ (i.e., AI-NPF and NR) caused a significant (p < 0.05) inhibition of urease activity, wherein a significant (p < 0.05) increase in the activity of catalase was observed, representing serious oxidative stress. Accordingly, NPF, AI-NPF, and NR differently affected soil bacterial abundance, diversity, and community compared to CuSO₄, which could have resulted from the changes in the bioavailable Cu concentration as a result of the distinct nature of copper spiked (i.e., nano form versus salt). Moreover, minor differences in the soil enzyme activity and bacterial community were observed between NPF and AI-NPF, reflecting that the impact of the Cu(OH)₂ nanopesticide was primarily attributed to the presence of nano-Cu(OH)₂. In total, the impacts of nano-Cu(OH)₂ on the soil bacterial community and enzyme activity tested in this study differed from CuSO₄, shedding light on the environmental risks of the Cu(OH)₂ nanopesticide in the long run.

Identification of the co-existence of low total organic carbon contents and low pH values in agricultural soil in north-central Europe using hot spot analysis based on GEMAS project data

Total organic carbon (TOC) contents in agricultural soil are presently receiving increased attention, not only because of their relationship to soil fertility, but also due to the sequestration of organic carbon in soil to reduce carbon dioxide emissions. In this research, the spatial patterns of TOC and its relationship with pH at the European scale were studied using hot spot analysis based on the agricultural soil results of the Geochemical Mapping of Agricultural Soil (GEMAS) project. The hot and cold spot maps revealed the overall spatial patterns showing a negative correlation between TOC contents and pH values in European agricultural soil. High TOC contents accompanying low pH values in the north-eastern part of Europe (e.g., Fennoscandia), and low TOC with high pH values in the southern part (e.g., Spain, Italy, Balkan countries). A special feature of co-existence of comparatively low TOC contents and low pH values in north-central Europe was also identified on hot and cold spot analysis maps. It has been found that these patterns are strongly related to the high concentration of SiO₂ (quartz) in the coarse-textured glacial sediments in north-central Europe. The hot spot analysis was effective, therefore, in highlighting the spatial patterns of TOC in European agricultural soil and helpful to identify hidden patterns.

Potential environmental risks of nanopesticides: Application of Cu(OH)2 nanopesticides to soil mitigates the degradation of neonicotinoid thiacloprid

Cu(OH)₂ nanopesticides and organic insecticides are continuously applied to soil at a temporal interval, while knowledge about the impact of Cu(OH)₂ nanopesticides on organic insecticides degradation is currently scarce, resulting in poorly comprehensive evaluation of the potential environmental risks of Cu(OH)₂ nanopesticides. Herein, a commercial Cu(OH)₂ nanopesticide formulation (NPF), the active ingredient of NPF (AI-NPF), the prepared Cu(OH)₂ nanotubes (NT) with comparable morphology and size to AI-NPF, and CuSO₄ were respectively applied to soil at normal doses (0.5, 5 and 50 mg/kg), followed by an application of neonicotinoid thiacloprid after an interval of 21 d, showing that NPF at doses of 5 and 50 mg/kg significantly (p < 0.05) mitigated thiacloprid degradation compared to control and CuSO₄. Furthermore, AI-NPF was the primary component that contributed to the mitigation effect of NPF, which was also validated by the NT. Large differences in the degradation efficiency of thiacloprid in sterilized and unsterilized soils with Cu(OH)₂ nanopesticides suggested that biodegradation was the primary process responsible for thiacloprid degradation, especially as chemical degradation was negligible. Besides a decrease of thiacloprid bioavailability due to adsorption by Cu(OH)₂ nanopesticides, we demonstrated that Cu(OH)₂ nanopesticides changed soil microbial communities, reduced nitrile hydratase activity and down-regulated thiacloprid-degradative nth gene abundance, which thus mitigated thiacloprid biodegradation. Clearly, this study shed light on the potential environmental risks of Cu(OH)₂ nanopesticide.

A new test system for unraveling the effects of soil components on the uptake and toxicity of silver nanoparticles (NM-300K) in simulated pore water

Fate, bioavailability and toxicity of silver nanoparticles (AgNP) are largely affected by soil properties. Here we focused on how these processes are connected in simulated soil pore water. OECD soil components (sand, kaolin clay, peat) were covered with NM-300K-, AgNO₃- and NM-300K dispersant-contaminated water, and Folsomia candida were exposed on the water surface. After 14 days the majority of AgNP was in nano form in sand pore water where also silver uptake was highest. Multilayered cross sections from X-ray micrographs of Collembola exposed to AgNP showed that silver was located in animal areas of direct contact to the contaminated pore water and was ingested. In contrast, in simulated peat pore water only a small fraction of silver was bioavailable. AgNO₃ was only bioavailable at the start of the test and not anymore at test end. AgNP and AgNO₃ caused immobilization in sand and kaolin pore water while no toxicity was found with peat and OECD soil. A strong correlation (correlation coefficient = 0.901) existed between the concentration of nano silver and immobilization; for ionic silver this was not the case. The dispersant of AgNP was toxic on its own in sand and kaolin pore water. As there are analytical limitations of quantifying AgNP in complex matrices this test system enables a mechanistic view of exposure and uptake of AgNP (and other substances) by F. candida from soil pore water.

Structural Transformation to Attain Responsible BIOSciences (STARBIOS2): Protocol for a Horizon 2020 Funded European Multicenter Project to Promote Responsible Research and Innovation

BACKGROUND

Promoting Responsible Research and Innovation (RRI) is a major strategy of the "Science with and for Society" work program of the European Union's Horizon 2020 Framework Programme for Research and Innovation. RRI aims to achieve a better alignment of research and innovation with the values, needs, and expectations of society. The RRI strategy includes the "keys" of public engagement, open access, gender, ethics, and science education. The Structural Transformation to Attain Responsible BIOSciences (STARBIOS2) project promotes RRI in 6 European research institutions and universities from Bulgaria, Germany, Italy, Slovenia, Poland, and the United Kingdom, in partnership with a further 6 institutions from Brazil, Denmark, Italy, South Africa, Sweden, and the United States.

OBJECTIVE

The project aims to attain RRI structural change in 6 European institutions by implementing action plans (APs) and developing APs for 3 non-European institutions active in the field of biosciences; use the implementation of APs as a learning process with a view to developing a set of guidelines on the implementation of RRI; and develop a sustainable model for RRI in biosciences.

METHODS

The project comprises interrelated research and implementation designed to achieve the aforementioned specific objectives. The project is organized into 6 core work packages and 5 supporting work packages. The core work packages deal with the implementation of institutional APs in 6 European institutions based on the structural change activation model. The supporting work packages include technical assistance, learning process on RRI-oriented structural change, monitoring and assessment, communication and dissemination, and project management.

RESULTS

The project is funded by Horizon 2020 and will run for 4 years (May 2016-April 2020). As of June 2018, the initial phase has been completed. The participating institutions have developed and approved APs and commenced their implementation. An observation tool has been launched by the Technical Assistance Team to collect information from the implementation of APs; the Evaluation & Assessment team has started monitoring the advancement of the project. As part of the communication and dissemination strategy, a project website, a Facebook page, and a Twitter account have been launched and are updated periodically. The International Scientific Advisory Committee has been formed to advise on the reporting and dissemination of the project's results.

CONCLUSIONS

In the short term, we anticipate that the project will have a considerable impact on the organizational processes and structures, improving the RRI uptake in the participating institutions. In the medium term, we expect to make RRI-oriented organizational change scalable across Europe by developing guidelines on RRI implementation and an RRI model in biosciences. In the long term, we expect that the project would help increase the ability of research institutions to make discoveries and innovations in better alignment with societal needs and values.

INTERNATIONAL REGISTERED REPORT IDENTIFIER (IRRID)

DERR1-10.2196/11745.

Effects of anastomotic technique on early postoperative outcome in open right-sided hemicolectomy

Background

Despite recent improvements in colonic cancer surgery, the rate of anastomotic leakage after right hemicolectomy is still around 6–7 per cent. This study examined whether anastomotic technique (handsewn or stapled) after open right hemicolectomy for right‐sided colonic cancer influences postoperative complications.

Methods

Patient data from the German Society for General and Visceral Surgery (StuDoQ) registry from 2010 to 2017 were analysed. Univariable and multivariable analyses were performed. The primary endpoint was anastomotic leakage; secondary endpoints were postoperative ileus, complications and length of postoperative hospital stay (LOS).

Results

A total of 4062 patients who had undergone open right hemicolectomy for colonic cancer were analysed. All patients had an ileocolic anastomosis, 2742 handsewn and 1320 stapled. Baseline characteristics were similar. No significant differences were identified in anastomotic leakage, postoperative ileus, reoperation rate, surgical‐site infection, LOS or death. The stapled group had a significantly shorter duration of surgery and fewer Clavien–Dindo grade I–II complications. In multivariable logistic regression analysis, ASA grade and BMI were found to be significantly associated with postoperative complications such as anastomotic leakage, postoperative ileus and reoperation rate.

Conclusion

Handsewn and stapled ileocolic anastomoses for open right‐sided colonic cancer resections are equally safe. Stapler use was associated with reduced duration of surgery and significantly fewer minor complications.

Is a Water Content of 60% Maximum Water Holding Capacity Suitable for Folsomia candida Reproduction Tests? A Study with Silver Nanoparticles and AgNO₃

Silver nanoparticles (AgNP) are increasingly emitted to the environment due to a rise in application in various products; therefore, assessment of their potential risks for biota is important. In this study the effects of AgNP at environmentally relevant concentrations (0.6–375 µg kg⁻¹ soil) on the soil invertebrate Folsomia candida in OECD (Organisation for Economic Co-operation and Development) soil was examined at different soil water contents. Animals were retrieved by heat extraction, which had an efficiency of about 90% compared with the floatation method. The tested water content range is set by OECD Guideline 232 (40–60% of the maximum water holding capacity, WHC), and we detected significant differences in toxicity due to these. With AgNO₃, used as an ionic control, the number of juveniles significantly decreased only at 40% WHC, which might be due to dilution of the toxicant at higher soil water content. In turn, at 60% WHC, the reproduction of F. candida significantly increased in the presence of AgNP compared with in the control. However, at this water content, the required number of juveniles in the control treatment was not reached in three independent tests. The fact that the OECD validity criterion is not met indicates that the soil conditions are not suitable for reproduction at 60% WHC.

[Surgical treatment of achalasia - endoscopic or laparoscopic? : Proposal for a tailored approach]

Primary idiopathic achalasia is the most common form of the rare esophageal motility disorders. A curative therapy which restores the normal motility does not exist; however, the therapeutic principle of cardiomyotomy according to Ernst Heller leads to excellent symptom control in the majority of cases. The established standard approach is Heller myotomy through the laparoscopic route (LHM), combined with Dor anterior fundoplication for reflux prophylaxis/therapy. At least four meta-analyses of randomized controlled trials (RCTs) have demonstrated superiority of LHM over pneumatic dilation (PD); therefore, LHM should be used as first line therapy (without prior PD) in all operable patients. Peroral endoscopic myotomy (POEM) is a new alternative approach, which enables Heller myotomy to be performed though the endoscopic submucosal route. The POEM procedure has a low complication rate and also leads to good control of dysphagia but reflux rates can possibly be slightly higher (20-30%). Long-term results of POEM are still scarce and the results of the prospective randomized multicenter trial POEM vs. LHM are not yet available; however, POEM seems to be the preferred treatment option for certain indications. Within the framework of the tailored approach for achalasia management of POEM vs. LHM established in Würzburg, we recommend long-segment POEM for patients with type III achalasia (spasmodic) and other hypercontractile motility disorders and potentially type II achalasia (panesophageal compression) with chest pain as the lead symptom, whereas LHM can also be selected for type I. For sigmoid achalasia, especially with siphon-like transformation of the esophagogastric junction, simultaneous hiatal hernia and epiphrenic diverticula, LHM is still the preferred approach. The choice of the procedure for revisional surgery in case of recurrent dysphagia depends on the suspected mechanism (morphological vs. functional/neuromotor).

Nanoparticles in the environment: where do we come from, where do we go to?

Nanoparticles serve various industrial and domestic purposes which is reflected in their steadily increasing production volume. This economic success comes along with their presence in the environment and the risk of potentially adverse effects in natural systems. Over the last decade, substantial progress regarding the understanding of sources, fate, and effects of nanoparticles has been made. Predictions of environmental concentrations based on modelling approaches could recently be confirmed by measured concentrations in the field. Nonetheless, analytical techniques are, as covered elsewhere, still under development to more efficiently and reliably characterize and quantify nanoparticles, as well as to detect them in complex environmental matrixes. Simultaneously, the effects of nanoparticles on aquatic and terrestrial systems have received increasing attention. While the debate on the relevance of nanoparticle-released metal ions for their toxicity is still ongoing, it is a re-occurring phenomenon that inert nanoparticles are able to interact with biota through physical pathways such as biological surface coating. This among others interferes with the growth and behaviour of exposed organisms. Moreover, co-occurring contaminants interact with nanoparticles. There is multiple evidence suggesting nanoparticles as a sink for organic and inorganic co-contaminants. On the other hand, in the presence of nanoparticles, repeatedly an elevated effect on the test species induced by the co-contaminants has been reported. In this paper, we highlight recent achievements in the field of nano-ecotoxicology in both aquatic and terrestrial systems but also refer to substantial gaps that require further attention in the future.

Toxicity of a Quinaldine-Based Liquid Organic Hydrogen Carrier (LOHC) System toward Soil Organisms Arthrobacter globiformis and Folsomia candida

The study aims to establish a preliminary environmental assessment of a quinaldine-based LOHC system composed of hydrogen-lean, partially hydrogenated, and fully hydrogenated forms. We examined their toxicity toward the soil bacteria Arthrobacter globiformis and the Collembola Folsomia candida in two exposure scenarios, with and without soil, to address differences in the bioavailability of the compounds. In both scenarios, no or only slight toxicity toward soil bacteria was observed at the highest test concentration (EC₅₀ > 3397 μmol L^-1 and >4892 μmol kg^-1 dry weight soil). The effects of the three quinaldines on F. candida in soil were similar, with EC₅₀ values ranging from 2119 to 2559 μmol kg^-1 dry weight soil based on nominal concentrations. Additionally, corrected pore-water-concentration-based EC₅₀ values were calculated by equilibrium partitioning using soil/pore-water distribution coefficients. The tests without soil (simulating pore-water exposure) revealed higher toxicity, with LC₅₀ values between 78.3 and 161.6 μmol L^-1 and deformation of the protective cuticle. These results assign the compounds to the category "harmful to soil organisms". Potential risks toward the soil environment of the test compounds are discussed on the basis of predicted no-effect concentrations.

How test vessel properties affect the fate of silver nitrate and sterically stabilized silver nanoparticles in two different test designs used for acute tests with Daphnia magna

The relation between test conditions such as medium composition or pH on silver nanoparticle (AgNP) behavior and its link to toxicity is one of the major topics in nanoecotoxicological research in the last years. In addition, the adaptation of the ecotoxicological standard tests for nanomaterials is intensely discussed to increase comparability and reliability of results. Due to the limitation of test material production volumes and the need for high-throughput screening, miniaturization has been proposed for several test designs. In the present study, the effect of a miniaturization of the acute Daphnia immobilization test on AgNP behavior was investigated. For this purpose, available, adsorbed, and dissolved silver fractions were measured using AgNP and silver nitrate in the following two test designs: a standard test (ST) design and a miniaturized test (MT) design with reduced test volume and less animals. Despite the increase in surface area in relation to the test volume in MT, more AgNP attached to the ST vessel surface, so that in this case, exposure concentrations were significantly lower compared to the MT assessment. Ionic silver concentrations resulting from AgNP dissolution were similar in both test designs. The same was observed for ionic silver concentrations in silver nitrate (AgNO₃) treatments, but adsorbed silver was also higher in ST treatments. Assessing the structure-activity relationships revealed that surface properties such as hydrophobicity, potential binding sites, or surface roughness were of higher importance than surface:volume ratios for both test substances.

Behavior and chronic toxicity of two differently stabilized silver nanoparticles to Daphnia magna

While differences in silver nanoparticle (AgNP) colloidal stability, surface potential, or acute aquatic toxicity for differently stabilized AgNP have often been reported, these have rarely been studied in long-term ecotoxicity tests. In the current study, we investigated the chronic toxicity of AgNP to Daphnia magna over a 21-day period with two different stabilizers (citrate and detergent), representative for charge and sterical stabilizers, respectively. This was coupled with a series of short-term experiments, such as mass balance and uptake/depuration testing, to investigate the behavior of both types of AgNP during a typical media exchange period in the D. magna test for chronic toxicity. As expected, the sterically stabilized AgNP was more stable in the test medium, also in the presence of food; however, a higher uptake of silver after 24h exposure of the charge stabilized AgNP was found compared to the detergent-stabilized AgNP (0.046±0.006μgAgμgDW(-1) and 0.023±0.005μgAgμgDW(-1), respectively). In accordance with this, the higher reproductive effects and mortality were found for the charge-stabilized than for the sterically-stabilized silver nanoparticles in 21-d tests for chronic toxicity. LOEC was 19.2μgAgL(-1) for both endpoints for citrate-coated AgNP and >27.5μgAgL(-1) (highest tested concentration for detergent-stabilized AgNP). This indicates a link between uptake and toxicity. The inclusion of additional short-term experiments on uptake and depuration is recommended when longer-term chronic experiments with nanoparticles are conducted.

Effects of soil treated glyphosate on growth parameters and chlorophyll content of maize Zea mays L. and bean Phaseolus vulgaris L. plants

Extended use of glyphosate poses the problem of its accumulation into soil and further on crops. The objective of this study was to evaluate the effects of different doses of soil glyphosate on growth parameters and chlorophyll content of maize Zea mays L. and bean Phaseolus vulgaris L. plants. An experiment was arranged in randomized complete blocks design with ten replications. Glyphosate solutions were applied to the soil in six concentrations, two subdoses of 0.1 and 0.2 g, the recommended dose of 0.4 g and three overdoses of 0.6, 0.8 and 1.0 g kg-1 of soil. An uncontaminated soil control was used. At 21, 28, 35 and 42 days after sowing (DAS), evaluations of plant height, number of leaves, stem diameter, leaf surface and plant injury were conducted. At 42 DAS, nodulation (in bean), root length, chlorophyll and dry matter yield were assessed. Already at the recommended dose and beyond, glyphosate caused significant damage to growth characteristics, nodulation and chlorophyll content in both plants. Some similar effects of the product were observed on the both plants at each time period. Therefore, there was an evidence that soil glyphosate already at the recommended dose had an inhibitory and even a phytocide effects on non-target plants.

[Diagnostics and therapy of achalasia]

The low incidence (1:100,000) makes primary idiopathic achalasia a problem of special importance. Patients often have a long medical history of suffering before the diagnosis is established and adequate therapy provided. Surgeons who perform antireflux surgery must be certain of detecting achalasia patients within their collective of gastroesophageal reflux disease (GERD) patients to avoid contraindicated fundoplication. The current gold standard for establishing the diagnosis of achalasia is manometry. Especially in early stages, symptom evaluation, endoscopy and barium swallow lack adequate sensitivity. High-resolution manometry (HRM) is increasingly used and allows characterization of different achalasia types (i.e. type I classical achalasia, type II panesophageal pressurization and type III spasmodic achalasia) and differentiation from other motility disorders (e.g. distal esophageal spasm, jackhammer esophagus and nutcracker esophagus). For patients over 45 years of age additional endoscopic ultrasound and computed tomography are recommended to exclude pseudoachalasia. A curative treatment restoring normal esophageal function does not exist; however, there are good options for symptom control. Therapy aims are abolishment of dysphagia, improvement of esophageal clearance, prevention of reflux and abolishment of chest pain. The current standard treatment is cardiomyotomy, which was first described 100 years ago by the German surgeon Ernst Heller and has been shown to be clearly superior when compared to endoscopic treatment (e.g. botox injection and balloon dilatation). Heller's myotomy procedure is preferentially performed via the laparoscopic route and combined with partial fundoplication. Currently, an alternative to performing Heller's myotomy via the endoscopic route is under intensive investigation in several centers worldwide. The peroral endoscopic myotomy (POEM) procedure has shown very promising initial results and warrants further clinical evaluation.

Does the exposure mode to ENPs influence their toxicity to aquatic species? A case study with TiO2 nanoparticles and Daphnia magna

Recent studies suggest that the ecotoxicity of engineered nanoparticles (ENPs) is dependent upon the treatment of ENPs in suspensions (e.g. sonication or use of solvents) and on the mode of exposure to test organisms. We conducted several bioassays with Daphnia magna in order to determine how adverse effects of TiO2 nanoparticles (n-TiO2) are influenced by experimental set-up. Several treatments were applied, including three test media, several treatments of n-TiO2 suspensions (stirring, sonication) and different exposure modes (exposure duration and volume of test suspension). No adverse effects were observed when D. magna were exposed to 50 mL of suspension, regardless of TiO2 concentration (up to 250 mg/L) and exposure duration. Conversely, adverse effects were observed when D. magna were exposed to 2 mL of suspension for 96 h with a 50 % effect concentration EC50 values ranging from 32 mg/L to 82 mg/L. Test media had no significant influence on the outcome of all treatments. For a better mechanistic understanding of the experimental set-up at which adverse effects were observed, the particle size of n-TiO2 in the test media was characterized throughout the test duration. These measurements revealed a fast and strong agglomeration with a secondary particle size in the order of magnitude of micrometers. Our study describes how the effects of n-TiO2 on D .magna are influenced by the duration of exposure and volume of media, highlighting the need for standardization of experimental methods.

[Peroral endoscopic myotomy for treatment of achalasia. Literature review and own initial experience]

Peroral endoscopic myotomy (POEM) is a new, purely endoscopic procedure for treatment of achalasia. Due to the lack of incisions POEM can be regarded as a true NOTES procedure. With POEM a myotomy is created in a similar fashion to the previous standard treatment, laparoscopic Heller myotomy (LHM). The relatively free choice of length and localization of the myotomy may be regarded as advantages of POEM. The procedure starts with a mucosal incision (mucosal entry) followed by preparation of a submucosal tunnel crossing the esophagogastric junction and creation of a myotomy in an antegrade direction before the mucosal access is closed with endoscopic clip placement. Since the first description of the application of POEM in humans in 2010 by the pioneer Haruhiro Inoue, Yokohama, Japan, it has been used increasingly and investigated in some centers in Asia, the U.S.A. and also Europe. The results are very promising. Although the procedure is technically demanding it can be performed safely with low complication rates. The POEM procedure achieves very good control of dysphagia and gastroesophageal reflux witch is only a rare side-effect witch is well-controllable with proton pump inhibitors (PPI). We review the currently available data from the literature and present our own initial series of  14 patients treated with POEM.

The coating makes the difference: acute effects of iron oxide nanoparticles on Daphnia magna

The surface of nanoparticles (NP) is often functionalized with a capping agent to increase their colloidal stability. Having a strong effect on the characteristics of NP, the coating might already determine the risk from NP to organisms and the environment. In this study identical iron oxide nanoparticles (IONP; Ø 5-6nm) were functionalized with four different coatings: ascorbate (ASC-IONP), citrate (CIT-IONP), dextran (DEX-IONP), and polyvinylpyrrolidone (PVP-IONP). Ascorbate and citrate stabilize NP via electrostatic repulsion whereas dextran and polyvinylpyrrolidone are steric stabilizers. All IONP were colloidally stable over several weeks. Their acute effects on neonates of the waterflea Daphnia magna were investigated over 96h. The highest immobilizing effect was found for ASC- and DEX-IONP. In the presence of neonates, both agglomerated or flocculated and adsorbed to the carapace and filtering apparatuses, inducing high immobilization. Lower immobilization was found for CIT-IONP. Their effect was hypothesized to partly originate from an increased release of dissolved iron and the ability to form reactive oxygen species (ROS). Furthermore, incomplete ecdysis occurred at high concentrations of ASC-, DEX-, and CIT-IONP. PVP-IONP did not induce any negative effect, although high quantities were visibly ingested by the daphnids. PVP-IONP had the highest colloidal stability without any occurring agglomeration, adsorption, or dissolution. Only strong swelling of the PVP coating was observed in medium, highly increasing the hydrodynamic diameter. Each coating caused individual effects. Toxicity cannot be correlated to hydrodynamic diameter or the kind of stabilizing forces. Effects are rather linked to decreasing colloidal stability, the release of ions from the core material or the ability to form ROS, respectively.

A miniaturized solid contact test with Arthrobacter globiformis for the assessment of the environmental impact of silver nanoparticles

Silver nanoparticles (AgNPs) are widely applied for their antibacterial activity. Their increasing use in consumer products implies that they will find their way into the environment via wastewater-treatment plants. The aim of the present study was to compare the ecotoxicological impact of 2 differently designed AgNPs using the solid contact test for the bacterial strain Arthrobacter globiformis. In addition, a miniaturized version of this test system was established, which requires only small-sized samples because AgNPs are produced in small quantities during the design level. The results demonstrate that the solid contact test can be performed in 24-well microplates and that the miniaturized test system fulfills the validity criterion. Soils spiked with AgNPs showed a concentration-dependent reduction of Arthrobacter dehydrogenase activity for both AgNPs and Ag ions (Ag(+)). The toxic effect of the investigated AgNPs on the bacterial viability differed by 1 order of magnitude and can be related to the release of dissolved Ag(+). The release of dissolved Ag(+) can be attributed to particle size and surface area or to the fact that AgNPs are in either metallic or oxide form. Environ

Adaptation of the Daphnia sp. acute toxicity test: miniaturization and prolongation for the testing of nanomaterials

Manufacturing of nanomaterials (NMs) is often complex and expensive, and their environmental risks are poorly understood or even unknown. An economization of testing NMs is therefore desirable, which can be achieved by miniaturizing test systems. However, the downsizing of test vessels and volumes can enlarge the surface/volume ratio (SVR) which in turn can affect the bioavailable concentration of adsorbing substances like NMs. The present study focused on the miniaturization of the acute toxicity test with Daphnia magna. The adaptations were verified with three reference substances, the non-adsorbing potassium dichromate (K2Cr2O7) and as potentially highly-adsorbing substances silver nanoparticles (AgNPs) and silver nitrate (AgNO3). The miniaturized test was conducted in 24-well microtiter plates (MT) and simultaneously compared to the OECD standard test (ST). Furthermore, the test duration was prolonged from 48 to 96 h since NMs tend to show effects only after extended exposure. The toxicity of K2Cr2O7 and AgNPs continued to increase within the prolonged test span. The test comparisons with K2Cr2O7 did not reveal any significant differences between ST and MT. AgNO3 toxicity was significantly decreased in MT compared to ST due to the enlarged SVR. The toxicity of AgNPs in MT after 24 h was equal to ST. Contrary to our expectations an exposure longer than 24 h resulted in an increase of AgNP toxicity in MT, possibly due to enhanced dissolution of silver. Microtiter plates are appropriate alternative test vessels for the Daphnia sp. acute toxicity test; thus, its miniaturization is feasible. The enlarged SVR has to be taken into account since it can affect the toxicity of potentially adsorbing substances. Furthermore, the standard test duration of 48 h might underestimate the toxicity of many substances, especially of NMs.

Intrinsically green iron oxide nanoparticles? From synthesis via (eco-)toxicology to scenario modelling

Iron oxide nanoparticles (IONP) are currently being studied as green magnet resonance imaging (MRI) contrast agents. They are also used in huge quantities for environmental remediation and water treatment purposes, although very little is known on the consequences of such applications for organisms and ecosystems. In order to address these questions, we synthesised polyvinylpyrrolidone-coated IONP, characterised the particle dispersion in various media and investigated the consequences of an IONP exposure using an array of biochemical and biological assays. Several theoretical approaches complemented the measurements. In aqueous dispersion IONP had an average hydrodynamic diameter of 25 nm and were stable over six days in most test media, which could also be predicted by stability modelling. The particles were tested in concentrations of up to 100 mg Fe per L. The activity of the enzymes glutathione reductase and acetylcholine esterase was not affected, nor were proliferation, morphology or vitality of mammalian OLN-93 cells although exposure of the cells to 100 mg Fe per L increased the cellular iron content substantially. Only at this concentration, acute toxicity tests with the freshwater flea Daphnia magna revealed slightly, yet insignificantly increased mortality. Two fundamentally different bacterial assays, anaerobic activated sludge bacteria inhibition and a modified sediment contact test with Arthrobacter globiformis, both rendered results contrary to the other assays: at the lowest test concentration (1 mg Fe per L), IONP caused a pronounced inhibition whereas higher concentrations were not effective or even stimulating. Preliminary and prospective risk assessment was exemplified by comparing the application of IONP with gadolinium-based nanoparticles as MRI contrast agents. Predicted environmental concentrations were modelled in two different scenarios, showing that IONP could reduce the environmental exposure of toxic Gd-based particles by more than 50%. Application of the Swiss "Precautionary Matrix for Synthetic Nanomaterials" rendered a low precautionary need for using our IONP as MRI agents and a higher one when using them for remediation or water treatment. Since IONP and (considerably more reactive) zerovalent iron nanoparticles are being used in huge quantities for environmental remediation purposes, it has to be ascertained that these particles pose no risk to either human health or to the environment.

Composition of body storage compounds influences egg quality and reproductive investment in the land snail Cornu aspersum

In invertebrates, resources available for growth and reproduction might influence the composition of body stores and subsequently nutrient allocation to eggs, thereby adjusting energy investment in reproduction. We investigated in the land snail Cornu aspersum (Müller, 1774) the efficiency of growth and the main storage compounds in the body and in eggs with respect to lipid content in food (5.5% versus 2.5%). The high body dry mass density of snails fed on lipid-rich diet underlined the high storage capacity of neutral lipids acquired during growth (high growth efficiency) without changing energy content because of the prevailing carbohydrate storage compounds. Reproductive investment was lower in these snails, and maternal effects decreased clutch size. Triglyceride allocation to eggs might enhance survival probability of offspring and therefore compensate for smaller clutch size. Snails fed on lipid-poor diet maximized their investment in clutch size whatever the amount of body stores, and allocated a higher amount of cholesterol to eggs. Cholesterol could be essential for embryo growth, as it ensures membrane functioning. In conclusion, the availability of resources can differentially affect nutrient allocation and energy investment in reproduction. Thus, the investigation of physiological processes becomes essential to understand population dynamics in fluctuating or changing habitats.

[Newly recognized side-effects of proton pump inhibitors. Arguments in favour of fundoplication for GERD?]

Among other indications proton pump inhibitors (PPIs) are used as medical treatment of gastroesophageal reflux disease (GERD) and are the most frequently prescribed and most frequently used drugs in gastroenterology. Until recently PPIs were regarded as very safe and associated with very few side-effects. However, during recent years study results have revealed many severe adverse events associated especially with long-term PPI use. We review the currently available evidence, regarding the side-effects of PPIs and discuss the potential impact on treatment strategies for GERD (conservative treatment vs. antireflux surgery). Currently available data suggest that PPIs are associated with osteoporosis-related fractures, Clostridium difficile associated diarrhea (CDAD), community and hospital-acquired pneumonia, pharmacologic interaction with clopidogrel and acetylsalicylic acid with subsequent increased rate of cardiovascular events, refractory hypomagnesemia and rebound reflux symptoms etc. The risk-benefit ratio of PPIs is increasingly recognized as being less favourable. This leads to a more critical viewpoint and raises the question whether the side-effects of PPIs may outweigh the benefits, especially with long-term use. The side-effects of PPIs seem to make a strong argument in favour of laparoscopic fundoplication in the treatment of GERD.

Adjustment of metabolite composition in the haemolymph to seasonal variations in the land snail Helix pomatia

In temperate regions, land snails are subjected to subzero temperatures in winter and hot temperatures often associated to drought in summer. The response to these environmental factors is usually a state of inactivity, hibernation and aestivation, respectively, in a temperature and humidity buffered refuge, accompanied by physiological adjustments to resist cold or heat stress. We investigated how environmental factors in the microhabitat and body condition influence the metabolite composition of haemolymph of the endangered species Helix pomatia. We used UPLC and GC-MS techniques and analyzed annual biochemical variations in a multivariate model. Hibernation and activity months differed in metabolite composition. Snails used photoperiod as cue for seasonal climatic variations to initiate a physiological state and were also highly sensitive to temperature variations, therefore constantly adjusting their physiological processes. Galactose levels gave evidence for the persistence of metabolic activity with energy expenditure during hibernation and for high reproductive activity in June. Triglycerides accumulated prior to hibernation might act as cryoprotectants or energy reserves. During the last month of hibernation snails activated physiological processes related to arousal. During activity, protein metabolism was reflected by high amino acid level. An exceptional aestivation period was observed in April giving evidence for heat stress responses, like the protection of cells from dehydration by polyols and saccharides, the membrane stabilization by cholesterol and enhanced metabolism using the anaerobic succinic acid pathway to sustain costly stress responses. In conclusion, physiological adjustments to environmental variations in Helix pomatia involve water loss regulation, cryoprotectant or heatprotectant accumulation.

Seasonally contrasting life-history strategies in the land snail Cornu aspersum: physiological and ecological implications

When a life history is characterized by both seasonality in reproduction and seasonality in offspring fitness, trade-offs in reproductive traits might be adjustments to seasonal time constraints to optimize reproductive success. Therefore, we compared in the laboratory the trade-offs in reproductive traits between early (after maturity) and delayed (after dormancy) reproduction in young land snails Cornu aspersum (Müller, 1774) (syn. Helix aspersa ), depending on food energy content. We also investigated the maternal investment in reproductive output in both breeding periods. After attaining maturity, snails produced single clutches with many small eggs, which resulted, in contrast to previous studies, in large offspring with a low hatching rate owing to high within-clutch cannibalism. The young cannibals may have a higher survival probability in the following hibernation. Snails starting to reproduce after hibernation had smaller clutches of larger eggs, resulting in high quantity of lighter offspring. The clutch mass was positively correlated with maternal mass in snails reproducing after having attained maturity and negatively correlated in snails reproducing after hibernation. Multiple oviposition occurred only after hibernation, thereby enhancing reproductive success. An energy-rich diet did not affect reproductive strategies. Further studies should focus on seasonal plasticity of reproductive strategies in natural populations of C. aspersum and investigate survival probabilities of breeders and juveniles in an evolutionary context.

An indispensable asset at risk: merits and needs of chemicals-related environmental sciences

BACKGROUND

Modern societies depend on environmental sustainability and on new generations of individuals well-trained by environmental research and teaching institutions. In the past, significant contributions to the identification, assessment, and management of chemical stressors with legal consequences have been made.

MAIN FEATURES

Within this article, we intend to elucidate the merits and the emerging challenges of chemicals-related environmental sciences. The manuscript is supported by more than 70 professors and university academics of leading institutions in Germany, Switzerland, Austria, and other countries in Europe, but addresses topics of global concern.

RESULTS AND DISCUSSION

Many environmental problems of pollutants remain to be addresses, since new chemical compounds or classes of new compounds are continuously developed and brought to the market and sooner or later "emerge" in the environment. Further issues are the inclusion of transformation products and chemical mixtures in environmental risk assessment, the long-term presence of xenobiotics bound to soils and sediments, as well as an understanding of the ecological relevance of ecotoxicological end points.

CONCLUSION AND PERSPECTIVES

We point out the need for a strong academic research and education system in chemicals-related environmental sciences to ministries, politicians, and research funding institutions and we propose to create specific units in the national funding bodies that address basic and interdisciplinary research in this field.

Ionic liquids in soils: effects of different anion species of imidazolium based ionic liquids on wheat (Triticum aestivum) as affected by different clay minerals and clay concentrations

This study contributes to a prospective hazard assessment of ionic liquids, focusing on the terrestrial environment. The influence of differently composed soils-varying contents of the clay minerals smectite and kaolinite-on the toxicity of different anion species of imidazolium based ionic liquids was studied for growth inhibition of wheat (Triticum aestivum). IM14 (CF(3)SO(2))(2)N appeared the most toxic, independently of the investigated soil type. The toxicity of IM14 Cl, IM14 BF(4) and IM14 HSO(4) was mainly dominated by the cationic moiety. The observed effects varied in dependence of the added clay type and clay concentration. An increase of clay content resulted in less pronounced effects of these substances. In contrast, for IM14 (CF(3)SO(2))(2)N the addition of clay minerals caused higher toxic effects in comparison to the reference soil. Our results give first hints for the assumption, that ionic liquids whose toxic action is based on the anionic moiety are especially hazardous for soils, particular for soils with high clay contents.

Sorption and desorption of imidazolium based ionic liquids in different soil types

This study investigates the influence of the two different clay minerals kaolinite and smectite as well as of organic matter on the cation sorption and desorption behaviour of three imidazolium based ionic liquids -1-butyl-3-methyl-imidazolium tetrafluoroborate (IM14 BF(4)), 1-methyl-3-octyl-imidazolium tetrafluoroborate (IM18 BF(4)) and 1-butyl-3-methyl-imidazolium bis[(trifluoromethyl)sulfonyl]imide (IM14 (CF(3)SO(2))(2)N) - in soil. The German standard soil Lufa 2.2 - a natural soil classified as a loamy sand - was the basis substrate for the different soil compositions and also served as a reference soil. The addition of organic matter and clays increases the sorption of the substances and in particular smectite had striking effects on the sorption capacity for all three ionic liquids indicating that ionic interactions play an important role for sorption and desorption processes of ionic liquids in soil. One exception was for kaolinite-containing soils and the IM14 cation: with (CF(3)SO(2))(2)N(-) as an anion the sorption was identical at either 10 wt% or 15 wt% clay content, and with BF(4)(-) sorption was even lower at 15 wt% kaolinite than at 10 wt%. Desorption was weak for IM18 BF(4), presumably owing to the longer alkyl side chain. With regard to the influence of kaolinite on desorption, the same pattern was observed as it was found for the sorption of IM14 BF(4) and IM14 (CF(3)SO(2))(2)N.

Environmental behavior and ecotoxicity of engineered nanoparticles to algae, plants, and fungi

Developments in nanotechnology are leading to a rapid proliferation of new materials that are likely to become a source of engineered nanoparticles (ENPs) to the environment, where their possible ecotoxicological impacts remain unknown. The surface properties of ENPs are of essential importance for their aggregation behavior, and thus for their mobility in aquatic and terrestrial systems and for their interactions with algae, plants and, fungi. Interactions of ENPs with natural organic matter have to be considered as well, as those will alter the ENPs aggregation behavior in surface waters or in soils. Cells of plants, algae, and fungi possess cell walls that constitute a primary site for interaction and a barrier for the entrance of ENPs. Mechanisms allowing ENPs to pass through cell walls and membranes are as yet poorly understood. Inside cells, ENPs might directly provoke alterations of membranes and other cell structures and molecules, as well as protective mechanisms. Indirect effects of ENPs depend on their chemical and physical properties and may include physical restraints (clogging effects), solubilization of toxic ENP compounds, or production of reactive oxygen species. Many questions regarding the bioavailability of ENPs, their uptake by algae, plants, and fungi and the toxicity mechanisms remain to be elucidated.

Effects of nickel chloride and oxygen depletion on behaviour and vitality of zebrafish (Danio rerio, Hamilton, 1822) (Pisces, Cypriniformes) embryos and larvae

We examined acute (2 h exposure of 5-day-old larvae) and subchronic (exposure from fertilization up to an age of 11 days) effects of NiCl(2).6H2O on embryos and larvae of zebrafish (Danio rerio), both alone and in combination with oxygen depletion. The following endpoints were recorded: acute exposure: locomotory activity and survival; subchronic exposure: hatching rate, deformations, locomotory activity (at 5, 8 and 11 days) and mortality. In acute exposures nickel chloride (7.5-15 mg Ni/L) caused decreasing locomotory activity. Oxygen depletion (<or=2.45+/-0.16 mg O2/L) also resulted in significantly reduced locomotory activity. In the subchronic test, exposure to >or=10 mg Ni/L resulted in delayed hatching at an age of 96 h, in decreased locomotory activity at an age of 5 days, and increased mortality at an age of 11 days (LC20=9.5 mg Ni/L). The observed LOEC for locomotory activity (7.5 mg Ni/L) is in the range of environmentally relevant concentrations. Since locomotory activity was already affected by acute exposure, this parameter is recommended to supplement commonly recorded endpoints of toxicity.

Biological effects of imidazolium ionic liquids with varying chain lengths in acute Vibrio fischeri and WST-1 cell viability assays

Detailed biological studies of methyl- and some ethylimidazolium ionic liquids in luminescent bacteria as well as in the IPC-81 (leukemia cells) and C6 (glioma cells) rat cell lines are presented. Effective concentrations in these test systems are generally some orders of magnitude lower than effective concentrations [corrected] of the conventional solvents acetone, acetonitrile, methanol, and methyl t-butyl ether. No general influence of the anionic compound in the ionic liquids on toxicity could be found, although they seem to modulate toxicity in some cases. The clear influence of the alkyl chain length on toxicity was quantified by linear regression analysis. Alkyl chain length of the longer alkyl chain was varied from 3 to 10 carbon atoms. Consequences for a design of sustainable alternative solvents are briefly sketched.