Proceedings, 2023, EcoBalt 2023

The assessment of pollution is a serious issue and a major consequence of the overgrowing human population and its activities. Focusing on the aquatic ecosystem, traditional approaches of water chemistry mainly provide minimal monitoring with the detection of pollutants, while they fail to produce mechanistic or predictive insight. As such, effect-based methods have gained significant attention for the better mechanistic understanding of aquatic pollution. Among the key species used, daphnids have acquired a central position in aquatic toxicology and ecology. In this study, a novel feeding assay was developed and applied in a battery of exposures to different pollutants. Furthermore, in combination with biochemical markers and sensitive metabolomic analyses, the responses of daphnids following exposures were uncovered in molecular detail. Specific categories of metabolites were identified as significant indicators to predict pollution. Full article

Herein, a proof of concept is reported, concerning the formulation of methacrylic and styrene-based hydrogels with adsorption properties versus the emerging pollutants (dyes, pesticides, and pharmaceuticals). The synthesis of the hydrogels was achieved by functionalizing the HEMA monomer with specifically chelating groups, such as amino acids (lysine and histidine), cyclodextrins, and meglumine. The as-prepared monomers were polymerized in water at different temperatures to obtain macroporous samples. All the samples were characterized by chemical–physical and morphological analyses confirming the success of the reactions. The resulting systems were successfully tested to adsorb 2, 4 D, methylene blue, and lomefloxacin. In addition, up to five cycles of regeneration tests were performed, confirming the aptitude of the samples to be used several times without losing efficiency and maintaining their mechanical properties. Full article

We live in the information age, but we still do not fully understand how the surrounding nature exchanges, collects, and manages information—both at the ecosystem and cellular levels. Still, it is crucial to possess a dynamic and developing comprehension of the functioning of nature in order to understand the phenomena occurring in our ever-changing world. Sometimes we encounter an attitude that there is no need to investigate anything further, as everything has already been researched. This is a very dangerous attitude. Without information, we should not actually talk about the age of information, and it is worth reviewing some knowledge that is deeply ingrained in us from time to time. Occasionally, it is worth taking a step back and considering whether we ourselves may have become trapped in dogmas that may hinder our understanding. This presentation focuses on various aspects of understanding nature, starting from single-celled organisms and ending with ecosystems. The topics that will be discussed among others are (1) infochemicals (how do they actually affect the biota?); (2) the remarkable process of cellular computation (does this imply that cellular materials can show a primitive intelligence?); and (3) the ability of plants to influence wind patterns and bring in more moisture from the ocean (what will happen to us when we excessively deforest?). Full article

One of the aims of The European Water Framework Directive (WFD) is that the Member States monitor and assess the ecological and chemical status of all surface water bodies (rivers, lakes, transitional and coastal waters) and to ensure that they achieve a good status by 2027, with an interim deadline of 2021 [...] Full article

In the renewable energy field, the conversion of solar light into electrical or chemical energy is considered essential to moving towards a truly green energy economy. Solar energy can be harnessed not just through generating electricity with photovoltaic cells but also by driving photoelectrochemical (PEC) reactions such as water splitting or pollutant oxidation. In this study, TiO₂ films were synthesized electrochemically through a procedure called plasma electrolytic oxidation (PEO). Under specific conditions, as the Ti substrate dissolves and the oxide film grows, electron discharges occur across the film, and this ionizes both the oxide and some amount of electrolyte that had been in contact with it. The mixture then cools, leaving a macroporous TiO₂ structure. What is particularly interesting for PEC applications is that the films can be crystalline and doped after synthesis. XRD analysis revealed that a TiO₂ film that had been obtained at a voltage of 200 V had an anatase crystal structure. In addition, during ionization and cooling, ions from the solution can be incorporated into the film. By adding 0.1 M Cu₂SO₄ into the synthesis electrolyte, we were able to incorporate Cu into the films, as proven EDX and XPS. The TiO₂ and heterostructured films showed good PEC water-splitting activity and stability in alkaline media when illuminated with 365 nm LED light. It was found that the photocurrent obtained depends on the synthesis voltage and that the heterostructured films would generate ~2 times larger photocurrents. In addition, further surface functionalization (e.g., with Au) was investigated. Electron–hole recombination was evaluated using an advanced non-stationary photoelectrochemical technique—intensity-modulated photocurrent spectroscopy (IMPS). Generally, films have very little recombination and only at lower overpotentials up to ~1 V. Overall, the synthesis of oxide films through PEO may provide an efficient alternative to obtaining crystalline films via annealing, and various heterostructures can be created simply by modifying synthesis conditions. Full article

The great increase in nanotechnology in the last 20 years has led to the alarming presence of nanomaterials in the environment as a new category of pollutants. Given the fact that legislation on nanomaterials is not concrete, the monitoring of their toxicity responses remains central. Focusing on tests in aquatic environments, daphnids are commonly employed as a bioindicator species for experiments with nanomaterials. However, until now, there has not been a unified and agreed approach to nanotoxicity testing, while research among different laboratories has been performed with significantly different setups, which may affect the reproducibility of the results. In this study, daphnids were exposed to silver nanoinks and the impact of surface to volume was assessed by comparing shallow vessels such as Petri dishes with deeper exposure vessels. Furthermore, in an attempt to assess whether the tests can be performed in smaller volumes, and thus in miniaturized versions, experiments compared larger and smaller volume setups. Finally, another parameter explored was the crowding of animals in exposure, and therefore their absolute number. Mortality was affected by both surface to volume and miniaturization, and significantly with crowding, supporting the implication of the number of animals in the tests. Further investigation with molecular and phenotypic endpoints confirmed these changes. Full article

Several plant species emit different volatile organic compounds constitutively under typical physiological conditions, and all plant species can be elicited to emit volatiles under stress conditions when physiological activity is curbed. Plant emissions constitute the biggest global source of reactive volatile organic compounds in the atmosphere. These volatiles play major biological roles in plant–plant interactions and in plant interactions with other organisms. In addition, plant-emitted volatiles often dominate the volatile-driven large-scale biosphere–atmosphere processes. In particular, plant volatiles participate in ozone- and secondary organic aerosol (SOA)-forming reactions and in cloud formation. Both enhanced SOA and cloud formation contribute to the cooling of the Earth’s surface, implying that plants can alter their own life environment. At the global scale, amelioration of vegetation growing conditions via volatile emissions can reduce the rate of global environmental change, but there are currently major uncertainties in understanding how plant emissions change in future climates and the quantitative impact of plant emissions on future climate change. Climate change is a complex phenomenon that entails alterations in a series of environmental factors. For plants, climate change is expected to enhance the severity and duration of stress periods when plant physiological activity is strongly reduced. This includes both the enhancement of abiotic stresses such as rising temperatures and more severe drought episodes in many parts of the globe and more devastating biotic stresses such as frequent outbreaks of herbivore and pathogen attacks. These changes in the frequency and duration of stress episodes can strongly impact volatile emissions. Stress typically reduces the emissions of constitutively released plant volatiles and elicits emissions of specific volatiles in a stress-severity-dependent manner. Thus, the plant-dependent feedback on global change is expected to become stronger in more stress-prone climates. Full article

Measurement quality is about fulfilling analytical requirements, which should be based on the intended use of the results. Within the European Union, environmental requirements can be set in a directive based on the maximum allowable concentration of a substance in air, soil or water, e.g., an Environmental Quality Standard (EQS) or an Emission Limit Value (EVS); and the requirements on measurement quality, e.g., the limit of quantification (LOQ), within-laboratory reproducibility (s_Rw) or measurement uncertainty (MU). This presentation is about publicly available guidelines that can help the analytical chemist working in the laboratory by implementing a specific method to (1) set up internal quality control over the whole concentration range based on the requirements through the use of target control limits, (2) perform ongoing internal quality control based on only two rules, (3) plan method validation, and (4) estimate the MU based on quality control and validation data. Normally for instrumental methods, the MU is estimated as a relative uncertainty at higher concentrations and as an absolute uncertainty at lower concentrations close to the LOQ. For quality control and MU estimation, free open source software will be presented. Full article

Chemical pollution affects the health of marine biota, key functions of the ecosystem, and endangers its biodiversity. The current environmental monitoring and assessment approach is based on chemical and ecological measurements, while the linkage between them, biological effects at the individual level, has been largely neglected. It is currently well acknowledged that the monitoring of chemical concentrations alone is not sufficient to protect populations; it considers only a tiny number of substances, while myriad others are left unnoticed. In addition, the hazards related to contaminant mixtures remain undetected. Biological effects of contaminants can be detected and measured at different levels of biological organization, i.e., from the molecular/biochemical level up to changes in populations and communities. In Baltic Sea monitoring programs, the few observations on the effects of contaminants have, for decades, mostly been made at only the higher biological organization levels, applying reproduction success parameters in top predators such as raptor birds and seals as indicators. However, recording early warning signals of contaminant exposure and effects on the health of individuals at lower biological levels makes it possible to anticipate and prevent damage at the higher levels. Moreover, it is also crucial to monitor effects at lower levels of the marine food web. The so-called biomarkers focus on changes in various biological functions and include parameters related to the detoxification of xenobiotics, oxidative stress, neurotoxicity, geno- and cytotoxicity and reproductive disorders, among others. Research on biomarkers aiming at improving their use in monitoring and assessing the contamination status of marine areas has been intensive during recent decades, although the implementation of the methods to monitoring programmes has been slow. Here, the current state of biological effects monitoring using biomarkers, as well as selected case studies in the Baltic Sea, are presented, followed by recommendations on their application in this sea area. Full article

The anthropogenic impact on the environment has long been known to negatively affect the quality of air. Volatile organic compounds (VOCs) are widely used in domestic and industrial applications, generally as solvents. They are mobile in both gaseous and aqueous phases, and thus their spread in environment could have massive effect with dramatically negative consequences. Pulsed corona discharge (PCD) and photocatalytic oxidation (PCO) are considered as efficient and eco-friendly methods for the energy-efficient abatement of gaseous hazardous pollutants. One of the main problems of PCD application in air treatment, however, is residual ozone, a side product of air ionization considered as secondary air pollution. Photocatalytic processes are known to degrade ozone extending simultaneously the photocatalyst lifetime. Thus, combining PCD and PCO in a two-step treatment system could solve the problem of the presence of residual ozone and complement each other’s strengths. In this study, experiments were conducted in separate systems, i.e. photocatalysis and plasma, making a prerequisite for the progress in the combined PCD/PCO applications. A prototype PCO reactor was built and tested with ozone and 2-methoxyethanol (2ME) in combinations. 2ME was chosen as a hazardous model VOC used in industry in solvents and paints. For the PCD experiments xylene was tested. Being refractory air pollutant, extensively studied for its removal, xylene provides a basis for the comparison of its abatement methods. The PCD treatment showed unequalled energy efficiencies in gaseous xylene oxidation. With respect to PCO experiments, the degradation of 2ME and ozone was 40% and 95%, respectively. High ozone degradation performed by PCO confirms the expediency of proposed air cleaning combination. Full article

Despite being the most abundant renewable resource in Estonia, wood has not been fully utilized for its potential value. To fully harness its potential, wood needs to be processed to its core components, such as fibers, wood sugars, and lignin, using chemical, thermochemical, or enzymatic methods. Researchers at TalTech are working on developing a comprehensive value chain for wood valorization, encompassing the production of food additives, thermoplastics, coating materials, and fine chemicals. Traditionally, lignin, a byproduct of the wood fractionation, was burned for energy. However, TalTech researchers are now using lignin to create novel thermoplastics, catalytic materials, and fine chemicals via fermentation processes. Here we show that the conversion of lignin into novel functional materials can be tailored by selecting appropriate extraction methods and source biomass. For instance, organosolv lignin extracted from barley straw exhibits the largest BET active surface area for lignin-based aerogels compared to those produced from softwood or hardwood organosolv lignins. Additionally, we showcase the potential of actinobacterial enzymes to detoxify phenol-containing wood sugar solutions, enabling their utilization in fermentation processes involving a wider array of microbial species. Full article