Towards AquaSun practical utilization: strong adhesion and lack of ecotoxicity of solar-driven antifouling sol-gel coating

The outcomes of adhesion and ecotoxicity tests carried out on metal specimens faithfully representing the surface of real ships, including the primer and tie coat layers typically applied on ship hull prior to deposition of the antifouling paint, show the practical applicability of "AquaSun" antifouling sol-gel coatings. Newly developed AquaSun coatings share superhydrophicity (contact angle >115) and exceptionally high scratch resistance (ASTM 5B). Coupled to the ecofriendly antifouling mechanism based on continuous H2O2 formation upon exposure to solar light and foul release due to low surface energy, these results open the route to the practical utilization of these novel marine coatings.

Towards AquaSun practical utilization: strong adhesion and lack of ecotoxicity of solar-driven antifouling sol-gel coating

The outcomes of adhesion and ecotoxicity tests carried out on metal specimens faithfully representing the surface of real ships, including the primer and tie coat layers typically applied on ship hull prior to deposition of the antifouling paint, show the practical applicability of "AquaSun" antifouling sol-gel coatings. Newly developed AquaSun coatings share superhydrophicity (contact angle >115) and exceptionally high scratch resistance (ASTM 5B). Coupled to the ecofriendly antifouling mechanism based on continuous H2O2 formation upon exposure to solar light and foul release due to low surface energy, these results open the route to the practical utilization of these novel marine coatings.

Action of Surfactants in Driving Ecotoxicity of Microplastic-Nano Metal Oxides Mixtures: A Case Study on Daphnia magna under Different Nutritional Conditions

The series of experiments presented in the paper served to clarify the effects of contemporary exposure to surfactant, microplastics (polyethylene and polyvinyl chloride), and nanoparticles (TiO2 and ZnO) on the model organism Daphnia magna. Exposure was evaluated with respect to the age of the organisms (“young”, 24 hours old, and “aged” 10 days old specimens), trophic status (feeding or fasting), and the simultaneous presence of a surfactant. All the above-mentioned substances are present in the wastewater coming from various environmental sources from cosmetic products. The experiments were conducted in compliance with the OECD 202:2004 guideline, which is also a reference for ecotoxicity tests required by REACH. The results showed that surfactants enhance effects of toxicity produced by the exposure to the microplastic + nanoparticle mixtures. The influence due to factors such as nutrition (effect in fasting >> feeding conditions) and the age of individuals (effects in older >> younger animals) is essential. Concerning young individuals, exposure to PE-TiO2 is the most significant in terms of effects produced: it is very significant, especially in the presence of surfactant (both under fasting and feeding conditions). On the contrary, exposure to the PE-Zn mixture shows the minor effects. The comparison with the literature, especially as regards the possibility of interpreting the toxicity trends for the various mixtures with respect to the individual elements that compose them, leads to hypothesize additive effects still to be investigated and confirms the greatest toxicity contribution of TiO2.

Ecotoxicological evaluation of construction products: inter-laboratory test with DSLT and percolation test eluates in an aquatic biotest battery

Background A European inter-laboratory test with 29 participating laboratories investigated whether a battery of four ecotoxicological tests is suitable for assessing the environmental compatibility of construction products. For this purpose, a construction product was investigated with the dynamic surface leaching test (DIN CEN/TS 16637-2) and the percolation test (DIN CEN/TS 16637-3). The eluates were produced centrally by one laboratory and were tested by the participants using the following biotests: algae test (ISO 8692), acute daphnia test (ISO 6341), luminescent bacteria test (DIN EN ISO 11348), and fish egg test (DIN EN ISO 15088). As toxicity measures, EC50 and LID values were calculated. Results Toxic effects of the eluates were detected by all four biotests. The bacteria test was by far the most sensitive, followed by the algae test and the daphnia test; the fish egg test was the least sensitive for eluates of both leaching tests. The toxicity level of the eluates was very high in the bacteria, daphnia, and algae test, with lowest ineffective dilution values of LID = 70 to LID = 13,000 and corresponding EC50 values around or even below 1 volume percent. The reproducibility (approximated by interlaboratory variability) of the biotests was good (< 53%) to very good (< 20%), regardless of the toxicity level of the eluates. The reproducibility of the algae test was up to 80%, and thus still acceptable. Conclusion It can be confirmed that the combination of leaching and ecotoxicity tests is suitable to characterize with sufficient reproducibility the environmental impact posed by the release of hazardous substances from construction products.

Synthesis, Characterization and Ecotoxicity Evaluation of Biochar-Derived Carbon Dots from Spruce Tree, Purple Moor-Grass and African Oil Palm

Biochar-derived C-Dots from Picea, Molinia caerulea and Elaeis guineensis were synthesized through a hydrothermal process, and their physicochemical and optical characteristics and environmental effects were compared. These C-Dots were characterized by techniques such as Attenuated Total Reflection–Fourier Transform Infrared (ATR-FTIR), UV-Vis spectrophotometry, fluorescence spectroscopy, dynamic light scattering (DLS), Z potential, and High-Resolution Transmission Electronical Microscopy (HR-TEM). The ecotoxicity tests were performed using the Microtox™ test, making this study one of the few that use this method. The C-Dots from Molinia caerulea showed the best quantum yield (QY) of 8.39% and moderate ecotoxicity, while Elaeis guineensis has the lowest QY (2.31%) but with zero toxicity. Furthermore, the C-Dots from Picea presents good optical properties but showed high toxicity and limits its use. Finally, all C-Dots showed functional groups that could be biofunctionalized with biomolecules, especially C-Dots from Molinia caerulea and Elaeis guineensis show potential for use in the development of optical biosensors.

Secondary Effects of Hypochlorite Treatment on the Emerging Pollutant Candesartan: The Formation of Degradation Byproducts and Their Toxicological Profiles

In recent years, many studies have reported the frequent detection of antihypertensive agents such as sartans (olmesartan, valsartan, irbesartan and candesartan) in the influents and effluents of wastewater treatment plants (WWTPs) and in the superficial waters of rivers and lakes in both Europe and North America. In this paper, the degradation pathway for candesartan (CAN) was investigated by simulating the chlorination process that is normally used to reduce microbial contamination in a WWTP. Twelve isolated degradation byproducts (DPs), four of which were isolated for the first time, were separated on a C-18 column by employing a gradient HPLC method, and their structures were identified by combining nuclear magnetic resonance and mass spectrometry and comparing the results with commercial standards. On the basis of these results, a mechanism of formation starting from the parent drug is proposed. The ecotoxicity of CAN and its DPs was studied by conducting a battery of ecotoxicity tests; bioassays were performed using Aliivibrio fischeri (bacterium), Daphnia magna (planktonic crustacean) and Raphidocelis subcapitata (alga). The ecotoxicity results shed new light on the increased toxicity of DPs compared with the parent compound.

Stavební odpad jako náhrada jemné frakce v betonech – hodnocení fytotoxicity vůči okřehku

Stavebnictví patří mezi největší odběratele nerostných surovin, s čímž souvisí i následná produkce odpadů. Výroba nejvíce využívaných produktů v tomto odvětví, jako jsou například cihly a betony, je v současné době závislá na neustálé těžbě primárních materiálů z neobnovitelných zdrojů. Značný potenciál pro ušetření primárních zdrojů má ve stavebnictví opětovné využívání recyklátů. Pro využití odpadních materiálů jako náhrady určité složky betonu je důležité, aby byly zachovány jeho mechanické a chemické vlastnosti. Současně je na místě posoudit také míru dopadu na životní prostředí. Jednou z možností je provést výluhové zkoušky a následné testy ekotoxicity s vodními organismy. Cílem této práce bylo posoudit a porovnat fytotoxické účinky výluhů cihelného prachu, tří druhů písků z betonových recyklátů a referenčního materiálu (přírodního písku). Hodnocen byl růst biomasy a množství chlorofylu. Výsledky ukázaly velké rozdíly mezi vzorky. Písek nepůsobil toxicky, účinky výluhu cihelného prachu se téměř nelišily od kontroly. Beton, který byl již jednou ecyklován, působil mírně inhibičně, zatímco výluhy podlahového betonu s obsahem epoxidového lepidla a betonu pocházejícího z dálnice měly výrazné toxické až letální účinky. Abstract (EN) Construction sector is one of the largest consumers of mineral resources, which is also related to the subsequent production of waste. The production of the most widely used products in this sector, such as bricks and concrete, is currently dependent on the constant extraction of primary materials from non-renewable resources. The reuse of recycled materials in the construction industry has considerable potential for saving of the primary resources. For the use of waste materials as a substitute for a certain component of concrete, it is important that its mechanical and chemical features remain unchanged. At the same time, it is appropriate to assess the degree of impact on the environment. One option is to perform leaching tests and subsequent ecotoxicity tests with aquatic organisms. The aim of this study was to determine and compare the phytotoxic effects of brick powder extracts, three types of recycled concrete aggregate and reference material (natural aggregate). Biomass growth and chlorophyll levels were evaluated. The results showed large differences among the samples. The sand was not toxic, the effect of brick dust was almost the same as the control. Concrete, which has already been recycled once, had a slightly inhibitory effect, while extracts of floor concrete containing epoxy glue and concrete from the highway had significant toxic to lethal effects.

Considerations for using reproduction data in toxicokinetic-toxicodynamic modelling

Toxicokinetic-toxicodynamic (TKTD) modelling is essential to make sense of the time dependence of toxic effects, and to interpret and predict consequences of time-varying exposure. These advantages have been recognised in the regulatory arena, especially for environmental risk assessment (ERA) of pesticides, where time-varying exposure is the norm. We critically evaluate the link between the modelled variables in TKTD models and the observations from laboratory ecotoxicity tests. For the endpoint reproduction, this link is far from trivial. The relevant TKTD models for sub-lethal effects are based on Dynamic-Energy Budget (DEB) theory, which specifies a continuous investment flux into reproduction. In contrast, experimental tests score egg or offspring release by the mother. The link between model and data is particularly troublesome when a species reproduces in discrete clutches, and even more so when eggs are incubated in the mother's brood pouch (and release of neonates is scored in the test). This situation is quite common among aquatic invertebrates (e.g., cladocerans, amphipods, mysids), including many popular test species. We discuss these and other issues with reproduction data, reflect on their potential impact on DEB-TKTD analysis, and provide preliminary recommendations to correct them. Both modellers and users of model results need to be aware of these complications, as ignoring them could easily lead to unnecessary failure of DEB-TKTD models during calibration, or when validating them against independent data for other exposure scenarios.