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Veröffentlichung Influence of flow rate and particle size on local equilibrium in column percolation tests using crushed masonry(2019) Bandow, Nicole; Finkel, Michael; Grathwohl, PeterColumn leaching tests are frequently used and accepted for investigation of release of hazardous substances from solid materials. Independent of differences due to the field of application or national regulations, column tests assume that local equilibrium is established in the experiment which facilitates transfer of results to field conditions. In the process of harmonization and standardization within Europe the question on the influence of flow rate and grain size distribution on the local equilibrium was raised. Thus, a set of experiments using two different masonry materials with varying grain size distribution and flow rate were conducted including stop/flow experiments. Results are compared to a numerical model which takes intraparticle pore diffusion-controlled release of Mo and V into the percolating water into account. Due to the relatively high intraparticle porosity of the materials (24-29%) data and model indicate that initially equilibrium-state conditions prevail followed by rapidly decreasing concentrations. The model fits data for Mo and V reasonably well; however, after the initial decline of concentrations (at L/S>2) extended tailing is observed especially of elements occurring as oxides, which is not captured by the model. © 2020 Springer Nature Switzerland AGVeröffentlichung Using environmental simulations to test the release of hazardous substances from polymer-based products: Are Rrealism and pragmatism mutually exclusive objectives?(2020) Aitken, Michael D.; Bandow, Nicole; Geburtig, AnjaThe potential release of hazardous substances from polymer-based products is currently in the focus of environmental policy. Environmental simulations are applied to expose such products to selected aging conditions and to investigate release processes. Commonly applied aging exposure types such as solar and UV radiation in combination with water contact, corrosive gases, and soil contact as well as expected general effects on polymers and additional ingredients of polymer-based products are described. The release of substances is based on mass-transfer processes to the material surfaces. Experimental approaches to investigate transport processes that are caused by water contact are presented. For tailoring the tests, relevant aging exposure types and release quantification methods must be combined appropriately. Several studies on the release of hazardous substances such as metals, polyaromatic hydrocarbons, flame retardants, antioxidants, and carbon nanotubes from polymers are summarized exemplarily. Differences between natural and artificial exposure tests are discussed and demonstrated for the release of flame retardants from several polymers and for biocides from paints. Requirements and limitations to apply results from short-term artificial environmental exposure tests to predict long-term environmental behavior of polymers are presented. Source: https://www.mdpi.comVeröffentlichung Investigating the ecotoxicity of construction product eluates as multicomponent mixtures(2023) Heisterkamp, Ines; Gartiser, Stefan; Schoknecht, Ute; Ilvonen, OutiBackground The release of hazardous compounds from construction products can harm human health and the environment. To improve the sustainability of construction materials, the leaching of substances from construction products and their potential environmental impact should be assessed. Twenty-seven construction products from different product groups were examined with a combination of standardized leaching tests (dynamic surface leaching test and percolation test) and biotests (algae, daphnia, fish egg, luminescent bacteria, umu and Ames fluctuation tests). To identify the released substances, extensive qualitative and quantitative chemical analyses were performed, including gas chromatographic and liquid chromatographic screening techniques. Results Many of the tested eluates caused significant ecotoxic effects. Particularly high ecotoxicities were observed for grouts (lowest ineffective dilution (LID) up to 16384) and cork granules (LID up to 24578). The results of ecotoxicity tests allow the prioritization of the eluates that should be subjected to detailed chemical analyses. Organic screening by different methods and ranking the identified substances based on recorded hazard classification is a suitable approach to identify the relevant toxic substances. Conclusions Determining the ecotoxicity of eluates from construction products records the summary effect of all leachable substances. This instrument is especially useful for construction products of complex and largely unknown composition. The ecotoxicological and the chemical-analytical approach complement each other in an ideal way to characterize the potential hazard of eluates from construction products and to identify the environmentally hazardous components in these eluates. Our results confirm that the proposed harmonized methods for testing eluate toxicity are an adequate and applicable procedure to move toward a more sustainable way of building and to reduce toxic effects of construction products in their use phase in the environment. © The Author(s) 2023