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The accumulation of organic pollutants in vegetables is a major global food safety issue. The concentrations of pollutants in vegetables usually differ across different tissues because of different transport and accumulation pathways. However, owing to the limitations of conventional methods, in situ localization of typical organic pollutants such as phthalate esters (PAEs) in plant tissues has not yet been studied. Here, we developed a quick and efficient method for in situ detection and imaging of the spatial distribution of PAEs in a typical root vegetable, carrot, using matrix-assisted laser desorption/ionization imaging mass spectrometry (MALDI-IMS). The use of a 2,5-dihydroxybenzoic acid matrix with a spray-sublimation coating method led to the successful identification of PAEs ion signals. The IMS results showed that a typical PAE-di-(2-ethylhexyl)phthalate (DEHP) was broadly distributed in the cortex, phloem, and metaxylem, but was barely detectable in the cambium and protoxylem. Interestingly, MALDI-IMS data also revealed for the first time the spatial distribution of sugars and β-carotene in carrots. In summary, the developed method offers a new and practical methodology for the in situ analysis of PAEs and plant metabolites in plant tissues. As a result, it could provide a more intuitive understanding of the movement and transformation of organic pollutants in soil-plant systems.

Ferrate (Fe(VI)) salts like K

Environmental science & technology 56(23), 16546-16566 (2022). doi:10.1021/acs.est.2c02976, Published by American Chemical Society, Columbus, Ohio

Chemosphere : chemistry, biology and toxicology as related to environmental problems 232, 164-170 (2019). doi:10.1016/j.chemosphere.2019.05.038, Published by Elsevier Science, Amsterdam [u.a.]

The overuse and misuse of antibiotics in animal breeding for disease treatment and growth enhancement have been major drivers of the occurrence, diffusion, and accumulation of antibiotic resistance genes (ARGs) in wastewater. Strategies to combat ARG dissemination are pressingly needed for human and ecological safety. To achieve this goal, a biochar-based polymer, magnetic biochar/quaternary phosphonium salt (MBQ), was applied in livestock wastewater and displayed a high performance in bacterial deactivation and ARG decrease. Efficient antibacterial effects were achieved by both MBQ and quaternary phosphonium salt; however, the abundance and fold change of ARGs in the MBQ treatment indicated a more powerful ARG dissemination control than quaternary phosphonium salt. The application of MBQ evidently reduced the microbial diversity and may primarily be responsible for altering the ARG profiles in wastewater. Network, redundancy, and variation partitioning analyses were further employed to reveal that the microbial community and the presence of mobile genetic elements were two critical factors shaping the pattern of the antibiotic resistome in livestock wastewater. Considered together, these findings extend the application field of biochar and have important implications for reducing ARG dissemination risks in livestock wastewater.

The influence of an ionic functional group on the fate and behavior of chemicals in the environment has so far not been systematically investigated. This study, therefore, examines the following three substances with high structural similarity but differing charge: non-charged 4-n-dodecylphenol[phenylring

Das Umweltprogramm der Vereinten Nationen (UNEP) stellte 2019 große Lücken im Umgang mit dem weltweiten Management chemischer Substanzen fest. Um diese zu schließen, schlagen Wissenschaftler nun vor, einen Globalen Rat für Chemikalien und Abfälle ins Leben zu rufen.

The influence of an ionic functional group on the fate and behavior of chemicals in the environment has so far not been systematically investigated. This study, therefore, examines the following three substances with high structural similarity but differing charge: non-charged 4-n-dodecylphenol[phenylring-14C(U)] (14C-DP), negatively charged 4-n-dodecylbenzenesulfonicacid[phenylring-14C(U)] sodium salt (14C-DS−) and positively charged 4-n-dodecylbenzyltrimethylammonium chloride[phenylring-14C(U)] (14C-DA+). They were investigated in a soil simulation study according to the OECD 307 test guideline by measuring the distribution of the applied radioactivity (AR) among volatile, mineralized, extractable and non-extractable residues (NER) in one soil after 0, 1, 7, 14, 49, 84 and 124 days of incubation. Extractable portions of 14C were examined by means of radio-TLC and -HPLC analyses. Microbial activity of the soil incubated with and without 14C-DP, 14C-DS− and 14C-DA+ was determined measuring the reduction of dimethylsulfoxide (DMSO) over time. After 124 days of incubation highest mineralization could be observed for 14C-DS− (64.5% AR). Except CO2, no volatile residues were formed over time. Besides the parent compounds, polar (14C-DP, 14C-DS− and 14C-DA+) and nonpolar (14C-DA+) transformation products were detected. Highest amounts of 14C were extracted using methanol and were thus potentially bioavailable for soil microorganisms. Microbial activity was markedly higher in soil incubated with 14C-DP and 14C-DS− compared to 14C-DA+ or soil without any treatment. Half-lives (DT50 k2) at 18 °C were as follows: DA+ (61.8 days) > DS− (18.2 days) > DP (10.0 days). In case of the cationic compound and its transformation products we conclude that a higher sorption affinity to soil particles leads to reduced bioavailability for microorganisms and thus reduced mineralization resulting in a higher persistence compared to anionic and non-charged organic compounds in soil. The impact of our findings on the persistence assessment of chemicals when performing OECD guideline tests in soil, water-sediment and surface water is discussed.

The influence of an ionic functional group on the fate of chemicals in the environment, especially the formation of non-extractable residues (NER), has not been systematically investigated. Using 4-n-dodecylphenol[phenylring

Quantification of nonextractable residues (NER) of pesticides in soil is feasible by use of radioactively labeled compounds, but structural information on these long-term stabilized residues is usually lacking. Microorganisms incorporate parts of the radiolabeled ((14)C-) carbon from contaminants into microbial biomass, which after cell death enters soil organic matter, thus forming biogenic nonextractable residues (bioNER). The formation of bioNER is not yet determinable in environmental fate studies due to a lack of methodology. This paper focuses on the development of a feasible analytical method to quantify proteinaceous carbon, since proteins make up the largest mass portion of bacterial cells. The test substance (14)C-bromoxynil after 56 days forms more than 70% of NER in soil. For further characterization of NER the amino acids were extracted, purified, and separated by two-dimensional thin-layer chromatography (TLC). Visualization of the (14)C-amino acids was performed by bioimaging, unambiguous identification by GC-MS and LC-MS/MS. Our analysis revealed that after 56 days of incubation about 14.5% of the (14)C-label of bromoxynil was incorporated in amino acids. Extrapolating this content based on the amount of proteins in the biomass (55%), in total about 26% of the NER is accounted for by bioNER and thus is not environmentally relevant.

Fish are warned about the presence of predators via an alarm cue released from the skin of injured conspecifics. The detection of this odor inherently initiates an antipredator response, which increases the chance of survival for the individual. In the present study, we assessed the effect of three commonly used pesticides on the antipredator response of zebrafish (Danio rerio). For this, we analyzed the behavioral response of zebrafish to a conspecific skin extract following 24 h of exposure to the respective contaminants. Results demonstrate that fish exposed to 20 μg/L of the organophosphate insecticide chlorpyrifos significantly reduced bottom-dwelling and freezing behavior, suggesting an impairment of the antipredator response. For the urea-herbicide linuron and the pyrethroid insecticide permethrin, no statistically significant effects could be detected. However, linuron-exposed fish appeared to respond in an altered manner to the skin extract; some individuals failed to perform the inherent behaviors such as erratic movements and instead merely increased their velocity. Furthermore, we determined whether zebrafish would avoid the pesticides in a choice maze. While fish avoided permethrin, they behaved indifferently to chlorpyrifos and linuron. The study demonstrates that pesticides may alter the olfactory-mediated antipredator response of zebrafish in distinct ways, revealing that particularly fish exposed to chlorpyrifos may be more prone to predation.

Global demand for alternative energy sources increases due to concerns regarding energy security and greenhouse gas emissions. However, little is known regarding the impacts of biofuels to the environment and human health even though the identification of such impacts is important to avoid biofuels leading to undesired effects. In this study mutagenicity and genotoxicity of the three biofuel candidates ethyl levulinate (EL), 2-methyltetrahydrofuran (2-MTHF) and 2-methylfuran (2-MF) were investigated in comparison to two petroleum-derived fuels and a biodiesel. None of the samples induced mutagenicity in the Ames fluctuation test. However, the Micronucleus assay revealed significant effects in Chinese hamster (Cricetulus griseus) V79 cells caused by the potential biofuels. 2-MF revealed the highest toxic potential with significant induction of micronuclei below 20.0 mg/L. EL and 2-MTHF induced micronuclei only at very high concentrations (>1000.0 mg/L). In regard to the genotoxic potential of 2-MF, its usage as biofuel should be critically discussed.

Many decades of research have shown that humic compounds as part of the soil organic matter (SOM) are essential for the stability and ecosystem services of soils. James P. Martin and Konrad Haider based on several pioneers in humus research improved the basis for the current knowledge of key processes in the soil environment, in particular structure and formation of humus triggered mainly by soil fungi. Other major contributions are briefly described but not in the focus of this article, such as their innovative tracer experiments with isotope-labelled xenobiotic chemicals and natural litter to study their fate. Both scientists inspired generations of younger researchers to advance their approaches and laid the cornerstone of the current understanding of soil organic matter formation. This article values the key experiments of Martin and Haider in this field and the related follow-up research finally resulting in the current view on formation mechanisms of SOM and non-extractable residues (NER) of xenobiotics. The improved understanding of these processes considering necromass with tissue residues of plants, microbes and animals challenges the traditional views of humic matter as macromolecular organic matrix, which according to the research of the last years represents only a variable part of the total organic matter besides associates of low molecular weight molecules. We discuss views on soil organic matter and humic substances that are nowadays considered not to differ in molecular diversity. We will start by demonstrating the understanding of humus characteristics and humus formation three decades ago closely related to the findings of Martin and Haider. Methodological approaches to characterize relevant structural and mechanistic pictures of SOM such as the priming effect, clay mineral catalysed reactions and the various mechanisms by which natural and xenobiotic chemicals are protected in soil are briefly illustrated by examples. Fungal activities in producing secondary metabolites like polyketides and their probably minor contributions to SOM formation are presented. Open research questions stimulated by these two soil scientists are sketched which are nowadays possible to address by new sophisticated high-resolution techniques.

Soils are faced with man-made chemical stress factors, such as the input of organic or metal-containing pesticides, in combination with non-chemical stressors like soil compaction and natural disturbance like drought. Although multiple stress factors are typically co-occurring in soil ecosystems, research in soil sciences on this aspect is limited and focuses mostly on single structural or functional endpoints. A mechanistic understanding of the reaction of soils to multiple stressors is currently lacking. Based on a review of resilience theory, we introduce a new concept for research on the ability of polluted soil (xenobiotics or other chemical pollutants as one stressor) to resist further natural or anthropogenic stress and to retain its functions and structure. There is strong indication that pollution as a primary stressor will change the system reaction of soil, i.e., its resilience, stability and resistance. It can be expected that pollution affects the physiological adaption of organisms and the functional redundancy of the soil to further stress. We hypothesize that the recovery of organisms and chemical-physical properties after impact of a follow-up stressor is faster in polluted soil than in non-polluted soil, i.e., polluted soil has a higher dynamical stability (dynamical stability=1/recovery time), whereas resilience of the contaminated soil is lower compared to that of not or less contaminated soil. Thus, a polluted soil might be more prone to change into another system regime after occurrence of further stress. We highlight this issue by compiling the literature exemplarily for the effects of Cu contamination and compaction on soil functions and structure. We propose to intensify research on effects of combined stresses involving a multidisciplinary team of experts and provide suggestions for corresponding experiments. Our concept offers thus a framework for system level analysis of soils paving the way to enhance ecological theory.

The demand for biofuels increases due to concerns regarding greenhouse gas emissions and depletion of fossil oil reserves. Many substances identified as potential biofuels are solvents or already used as flavors or fragrances. Although humans and the environment may be readily exposed little is known regarding their (eco)toxicological effects. In this study, the three potential biofuels ethyl levulinate (EL), 2-methyltetrahydrofuran (2-MTHF) and 2-methylfuran (2-MF) were investigated for their acute embryo toxicity and teratogenicity using the fish embryo toxicity (FET) test to identify unknown hazard potentials and to allow focusing further research on substances with low toxic potentials. In addition, two fossil fuels (diesel and gasoline) and an established biofuel (rapeseed oil methyl ester) were investigated as references. The FET test is widely accepted and used in (eco)toxicology. It was performed using the zebrafish Danio rerio, a model organism useful for the prediction of human teratogenicity. Testing revealed a higher acute toxicity for EL (LC50: 83mg/L) compared to 2-MTHF (LC50: 2980mg/L), 2-MF (LC50: 405mg/L) and water accommodated fractions of the reference fuels including gasoline (LC50: 244mg DOC/L). In addition, EL caused a statistically significant effect on head development resulting in elevated head lengths in zebrafish embryos. Results for EL reduce its likelihood of use as a biofuel since other substances with a lower toxic potential are available. The FET test applied at an early stage of development might be a useful tool to avoid further time and money requiring steps regarding research on unfavorable biofuels.