Assessing the transformation of chlorinated ethenes in aquifers with limited potential for natural attenuation: added values of compound-specific carbon isotope analysis and groundwater dating

The evaluation of biotransformation of chlorinated ethenes (CEs) in contaminated aquifers is challenging when variable redox conditions and groundwater flow regime are limiting factors. By using compound-specific stable carbon isotope analysis (C-CSIA) and ³H-³He based groundwater dating, we assessed three CE-contaminated field sites that differed in groundwater flow velocities, redox conditions, and level of contamination. CE isotopic signatures and carbon isotopic mass balances were applied to quantify CE transformation, whereas groundwater dating allowed determining degradation timescales and assessing hydrodynamic regimes. The combination of these techniques enabled at all field sites to indicate zones within the aquifers where CE dechlorination preferably occurred, sometimes even to metabolites of no toxic concern. However, the natural transformation processes were insufficient to mitigate the entire CE contamination at the studied sites. Such situations of limited transformation are worldwide far more common than sites where optimal natural (mainly redox) conditions are enabling complete CEs degradation. Despite such constraints for natural transformation, this study showed that even under non-favorable biogeochemical CEs degradation, the combination of CSIA and groundwater dating provide valuable information to the understanding of the fate of the CEs, thus, being an important contribution in the definition of efficient remediation measures at any given biogeochemical conditions.     

PCDD/F and dioxin-like PCB profiles in soils amended with sewage sludge,compost, farmyard manure,and mineral fertilizer since 1962

Background, aim, and scope  

Biowaste contains compounds of agricultural value such as organic carbon, nutrients, and trace elements and can partially replace mineral fertilizer (MIN) and improve the physical properties of the soil. However, the obvious benefits of land spreading need to be carefully evaluated against potential adverse effects on the environment and human health. Environmental contamination resulting from biowaste application is one of the key variables when assessing cost/benefits. This study provides data on the resulting concentration of polychlorinated dibenzodioxins and dibenzofurans (PCDD/Fs) and dioxin-like polychlorinated biphenyls (DL-PCBs) in the soil column as a result of the different types of fertilizers.     

"Ni-struvite" - a new biomineral formed by a nickel resistant Streptomyces acidiscabies

Biomineralization dependent on bacterial activity has been described for struvite which is formed in soils, guano, putrescent matter and sediments. A new biomineral containing nickel instead of magnesium, Ni(NH4)(PO4) . 6H2O, has been identified. It was formed by nickel resistant Streptomyces acidiscabies E13, and putatively named nickel struvite. The mineral formation is dependent on biological activity since non-viable bacterial cells are not capable to induce formation of Ni-struvite under identical conditions. Formation of Ni-struvite was observed on colony surfaces upon prolonged incubation of solid minimal or complex media containing elevated concentrations of 8-15mM NiCl2. The formation of magnesium containing crystals was not observed although Mg2+ is present in the medium. However, the process was not depending on desiccation since small crystals attached to the mycelial biomass of the bacteria were observed microscopically also in liquid cultures of nickel supplemented minimal and complex media after two weeks of incubation. The capacity to induce biomineralization of a nickel containing mineral is postulated to constitute a resistance factor, allowing the soil bacterium to withstand high nickel concentrations. The strain shows nickel resistance as an adaption to its habitat, since this bacterium was isolated from a former uranium mining site in Eastern Thuringia, Germany, where nickel concentrations of up to 2000ppm (translating to appr. 30mM) occur as a result of former mining activities.     

Prüfanforderungen des Umweltbundesamtes zur Bewertung der Auswirkungen von Pflanzenschutzmitteln auf terrestrische Pflanzen

The fundamental data requirements for the authorization of plant protection products and the inclusion of active ingredients in Annex I of Council Directive 91/414/EEC are described in the Annexes II and III of this Directive. Definite instructions with regard to preconditions and for implementation and methodology (guidelines) concerning investigations with terrestrial plants are deficient. In the following, the scientific data requirements are explained for assessing the effects of plant protection products on terrestrial plants.     

Urban nature at the fingertips: Investigating wild food foraging to enable nature interactions of urban dwellers

Meaningful human–nature interactions can counteract the extinction of experience and positively influence people’s nature relatedness, health and wellbeing. In this study, we explored urban wild food foraging to understand how best to enable human-nature interactions in cities by means of foraging. Using a structured questionnaire, a total of 458 residents of Vienna, Austria were surveyed. Sixty-four percent of visitors of public urban green spaces previously foraged for wild food species, whereas foraging frequencies were related to the targeted plant species and their life forms. People who foraged more frequently had greater nature relatedness, more childhood foraging experiences and lived on the outskirts of the city, but their socio-demographic backgrounds were heterogeneous. Social acceptance and lack of access to wild foods were perceived to be barriers. To promote nature relatedness through urban foraging, the legal framework, access to low-contamination foraging areas, availability of wild foods and social acceptance need to be improved.Supplementary InformationThe online version contains supplementary material available at 10.1007/s13280-021-01648-1.     

Chemical reactivities of ambient air samples in three Southern California communities

The potential adverse health effects of PM_2.5 (particulate matter with an aerodynamic diameter <2.5 μm) and vapor samples from three communities that neighbor railyards, Commerce (CM), Long Beach (LB), and San Bernardino (SB), were assessed by determination of chemical reactivities attributed to the induction of oxidative stress by air pollutants. The assays used were dithiothreitol (DTT)- and dihydrobenzoic acid (DHBA)-based procedures for prooxidant content and a glyceraldehyde-3-phosphate dehydrogenase (GAPDH) assay for electrophiles. Prooxidants and electrophiles have been proposed as the reactive chemical species responsible for the induction of oxidative stress by air pollution mixtures. The PM_2.5 samples from CM and LB sites showed seasonal differences in reactivities, with higher levels in the winter, whereas the SB sample differences were reversed. The reactivities in the vapor samples were all very similar, except for the summer SB samples, which contained higher levels of both prooxidants and electrophiles. The results suggest that the observed reactivities reflect general geographical differences rather than direct effects of the railyards. Distributional differences in reactivities were also observed, with PM_2.5 fractions containing most of the prooxidants (74–81%) and the vapor phase most of the electrophiles (82–96%). The high levels of the vapor-phase electrophiles and their potential for adverse biological effects point out the importance of the vapor phase in assessing the potential health effects of ambient air.

Implications:?PM_2.5 and its corresponding vapor phase, containing semivolatile organics, were collected in three communities in the Los Angeles Basin and examined with toxicologically relevant chemical assays. The PM_2.5 phase contained most of the prooxidants and the vapor phase contained most of the electrophiles, whose content was highest in summer samples from a receptor site that reflected greater photochemical processing of the air parcel during its transport. As electrophiles initiate both adverse and adaptive responses to foreign substances by biological systems, their presence in the vapor phase emphasizes the importance of this phase in the overall health effects of ambient air.     

Agonistic and antagonistic toxic effects observed with miniaturized growth and luminescence inhibition assays

Kinetic data recordings with miniaturized growth and luminescence inhibition assays with prokaryotes (Pseudomonas putida and Vibrio fischeri) reveal typical sample and species specific growth and light emission patterns respectively. Growth inhibiting influences, based on toxicokinetic and toxicodynamic sample specificities appeared in each growth phase. Agonistic and antagonistic effects of combinations of heavy metals like Cd2+, Hg2+ and Pb2+ and other compounds were easily recognized after accurate curve discussions. Some of the influences that made it more difficult to evaluate toxicological results only by restriction on EC values (effective concentrations) were investigated. The findings may lead to a more comprehensive interpretation of toxicological data and a presumption on the composition of complex samples in terms of screening investigations. Therefore, the conclusions demonstrate the possibilities and limits of kinetic data recordings in chronic and acute toxicity testing.     

Interlaboratory trial to determine the analytical state-of-the-art of bromate determination in drinking water

The new European Directive for water intended for human consumption has established a regulatory level for bromate at 10 microg L(-1). This Maximum Admissible Concentration requires analytical methods with detection limits of a least 2.5 microg L(-1). A project funded by the Standards, Measurements and Testing Programme of the European Commission has enabled the improvement and/or development of methods for the determination of bromate at such concentration levels. This collaborative work was concluded by the organisation of an interlaboratory trial involving 26 European laboratories, which enabled the testing of both a draft ISO Standard method and alternative methods. This paper presents the results of this interlaboratory trial, along with results of a bromate stability study. The progress made with respect to the analytical state-of-the-art for bromate will greatly benefit the quality of measurements carried out in water quality monitoring.