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Construction products are complex materials and contain a large number of different chemicals, which might be released to the environment during usage. Depending on the compound and on the matrix only a small portion is transferred to environment and therefore a risk assessment should be based on the available portion. Concerning the pathway to soil and groundwater by contact with rain or seepage water leaching tests were developed and standardized by CEN to determine the release potential of construction products. Chemical analysis in the eluates can be combined with eco-toxicological testing. In this presentation an overview about existing leaching methods is given using selected examples of our work. We especially draw the attention to research which is still needed to close the gap between the results of leaching experiments and the subsequent risk assessment of the products.
The eluates of 15 paints for outdoor use were used for a screening of organic compounds and the concentration of cations and anions were determined. Concerning the inorganic constituents only a small number of elements were present with concentrations higher than the limit of detection. Thus, leaching of potential hazardous chemicals is probably of higher concern. Several glycol ethers, polyalkylene glycols and some surfactants and coalescing agents have been identified. Among these only the latter are classified as hazardous to aquatic organisms. The identification of the organic compounds is a time consuming and labor-intensive step due to the high number of chemicals produced and used. Using eco-toxicity tests provides information on the environmental risk without the need for of chemical identification of all compounds. The screening of a set of construction products shows that only a part of eluates causes adverse effects in the test and that such screening can be used as a first step in the assessment of construction products. If this kind of testing is included in the evaluation concept an in depth chemical analysis is only needed for products showing adverse effects.
Determination of the eluate concentration after leaching enables to determine the potential release to the environment and to focus on the available fraction. However, limit values or other concepts to use this information in risk assessment are still missing.
Leaching and ecotoxicity tests are used as tools for the assessment of environmental compatibility of granular waste materials with potential for reuse.
The contribution gives an overview on the development of test conditions of leaching tests as well as research results on their robustness and performance. Examples of research results include the investigation of MSWI bottom ash, steel slag, contaminated soil, mining waste and other waste materials reused as construction products.
The background of application of ecotoxicological tests in Germany is given comprising the selection of tests, advantages and limitations and available guidelines.
The presentation will summarize German regulations on the reuse of contaminated soil-like materials (excavated soil, dredged sediments, mining residues, urban soils etc.). Leaching tests as available tools for the assessment of environmental compatibility are discussed. First results of a currently running project on the monitoring of such materials with a focus on PAH are presented.
A study on the leaching behavior of MSWI bottom ash fractions produced by an innovative wet processing technology using laboratory scale lysimeters will be presented in a second part.
The application of scrap tire granules as infill for synthetic turf and within elastic support layers of outdoor sports surfaces leads to the release of contaminants and transfer to soil and groundwater. The development of a special leaching procedure for synthetic sports surfaces and subsequent modelling of contaminant transfer to groundwater is presented in a third part of the presentation.
Auf dem Rostocker Bodenschutzsymposium 2017 wurden dem Fachpublikum die Ziele und erste Ergebnisse den laufenden UFOPLAN-Forschungsvorhabens "Monitoring zur Verwertung von Bodenmaterial" vorgestellt und diskutiert.
Ziel eines laufenden UFOPLAN-Vorhabens ist es, Datendefizite für Bodenmaterialien, die unter die neuen Kriterien der Verwertungsmöglichkeiten außerhalb der durchwurzelbaren Bodenschicht nach den §§ 6 bis 8 der Novelle der BBodSchV fallen, zu schließen und potenzielle Verwertungsmöglichkeiten aufzuzeigen.
Neben den Feststoffwerten wird dabei das Elutionsverhalten zur Bewertung herangezogen. Durch die Umstellung des Elutionsverfahrens von einem W/F von 10 l/kg (bisherige Regelung in der LAGA M 20) auf ein W/F von 2 l/kg bestehen erhebliche Unsicherheiten im Hinblick auf die Einstufung von Bodenmaterialien zur Verwertung.
Neben der Untersuchung relevanter Bodenmaterialien werden auch vorhandene Daten ausgewertet. Der Schwerpunkt der Untersuchungen wurde auf die Schadstoffgruppe der PAK gelegt. Dabei werden auch Probleme der Vergleichbarkeit verschiedener Verfahren der PAK-Analytik angesprochen.
Leaching tests are fundamental tools for the assessment of groundwater impact by contaminated soils concerning the soil-groundwater pathway. Such procedures are supposed to serve as the basis for a reliable leachate prognosis. They can be applied to determine the short and long term leaching behaviour as well as the source term of contaminated soils. For this purpose two types of leaching procedures have been validated in Germany for the examination of the leaching behaviour of frequently occurring organic substances (DIN 19528 - column test and DIN 19529 - batch test). A liquid-to-solid ratio (L/S) of 2 L/kg and 10 L/kg) is the basis for the risk assessment which is implemented in different German regulations. The equivalence of test results for both tests for the same material under investigation has been investigated for a variety of pollutants in order to assess their reliability in compliance testing. However, for emerging pollutants there is hardly data available on this issue.
Leaching tests on soils contaminated with emerging pollutants such as PFC (Perfluorinated Surfactants) are currently coming more into consideration due to the increasing detection of contaminated sites.
Therefore, two soils were investigated in this study from different contamination source (paper sludge containing compost and fire distinguishing foam) using both leaching tests and both liquid-to-solid ratios. The leachability of the various perfluorinated compounds in relation to their content in solid matter was considered. Furthermore the eluate pre-treatment prior analysis (in particular liquid/solid separation step needed for batch tests) has been taken into account.
The comparability of the results from batch and column is dependent on the solubility of the various compounds, on the L/S and on the turbidity in the eluates.
Ziel eines laufenden UFOPLAN-Vorhabens ist es, Datendefizite für Bodenmaterialien, die unter die neuen Kriterien der Verwertungsmöglichkeiten außerhalb der durchwurzelbaren Bodenschicht nach den §§ 6 bis 8 der Novelle der BBodSchV fallen, zu schließen und potenzielle Verwertungsmöglichkeiten aufzuzeigen.
Neben den Feststoffwerten wird dabei das Elutionsverhalten zur Bewertung herangezogen. Durch die Umstellung des Elutionsverfahrens von einem W/F von 10 l/kg (bisherige Regelung in der LAGA M 20) auf ein W/F von 2 l/kg bestehen erhebliche Unsicherheiten im Hinblick auf die Einstufung von Bodenmaterialien zur Verwertung.
Neben der Untersuchung relevanter Bodenmaterialien werden auch vorhandene Daten ausgewertet. Der Schwerpunkt der Untersuchungen wurde auf die Schadstoffgruppe der PAK gelegt. Dabei werden auch Probleme der Vergleichbarkeit verschiedener Verfahren der PAK-Analytik angesprochen.
Leaching tests are fundamental tools for the assessment of groundwater impact by contaminated soils concerning the soil-groundwater pathway. Such procedures are supposed to serve as the basis for a reliable leachate prognosis. They can be applied to determine the short and long term leaching behaviour as well as the source term of contaminated soils. For this purpose two types of leaching procedures have been validated in Germany for the examination of the leaching behaviour of frequently occurring organic substances (DIN 19528 - column test and DIN 19529 - batch test). A liquid-to-solid ratio (L/S) of 2 L/kg and 10 L/kg) is the basis for the risk assessment which is implemented in different German regulations. The equivalence of test results for both tests for the same material under investigation has been investigated for a variety of pollutants in order to assess their reliability in compliance testing. However, for emerging pollutants there is hardly data available on this issue. Leaching tests on soils contaminated with emerging pollutants such as PFC (Perfluorinated Surfactants) are currently coming more into consideration due to the increasing detection of contaminated sites. Therefore, two soils were investigated in this study from different contamination source (paper sludge containing compost and fire distinguishing foam) using both leaching tests and both liquid-to-solid ratios. The leachability of the various perfluorinated compounds in relation to their content in solid matter was considered. Furthermore the eluate pre-treatment prior analysis (in particular liquid/solid separation step needed for batch tests) has been taken into account.
The comparability of the results from batch and column is dependent on the solubility of the various compounds, on the L/S and on the turbidity in the eluates.
Electric arc furnace (EAF)slag is a complex multi-Phase system comparable to natural rock mineralogy, which can be used as a secondary rawmaterial. To ensure the environmental safety of EAF slags,regarding the mobility of contaminants,it is necessary to understand the Controlling mechanisms for the leaching of heavy metals such as chromium and Vanadium in this complex system.
Cadmiumhaltige Pigmente werden in Künstlerfarben (z.B. Cadmiumgelb PY35) verwendet und können beim Reinigen gebrauchter Pinsel mit Wasser über das Abwasser in die Kläranlagen eingetragen werden, wo sie auf Grund ihrer geringen Wasserlöslichkeit im Klärschlamm verbleiben. Bei landwirtschaftlicher Nutzung des Klärschlamms, kann das Cadmium nach Aufnahme in Pflanzen in die menschliche Nahrungskette gelangen. Aufnahme von Cadmium erhöht die Wahrscheinlichkeit an Brustkrebs zu erkranken und führt durch eine Verringerung der Knochendichte zu einer erhöhten Anzahl an Knochenbrüchen. Daher wurde bei der europäischen Chemikalienbehörde ECHA ein Verbotsantrag nach Annex XV von einem Mitgliedsland gestellt.
Mengenmäßig ist der Betrag an Cadmium, der über diesen Expositionsweg auf Agrarflächen eingetragen werden klein: 120 kg im Vergleich zu 120 Tonnen aus anderen Quellen. Zur Abschätzung des Risikos ist allerdings nicht nur die Gesamtmenge entscheidend, sondern auch die Mobilität der Schadstoffe. Um diese zu untersuchen wurden mit Cadmiumpigmenten dotierte Klärschlämme mit Boden gemischt und das Auswaschverhalten mit Hilfe von Säulenperkolationstests untersucht. Das Cadmium liegt in den Pigmenten als Cadmiumsulfid vor, dessen Löslichkeit stark vom Redoxpotential abhängt und dem pH-Wert abhängt. Daher wurden die Versuche unter verschiedenen Redoxbedingungen und mit einem sauren Eluenten durchgeführt.
Eluate wurden über einen Zeitraum von 68 h gesammelt und der pH-Wert, die Leitfähigkeit, die Trübung, Konzentration an organischen Kohlenstoff (TOC) und Cd bestimmt. Das Redoxpotential sinkt nach Start der Elution schnell und hängt von dem Gehalt an Kohlenstoff im Boden ab: Je höher der Gehalt ist, um so langsamer sinkt das Redoxpotential. Einen eindeutigen Zusammenhang zwischen Cadmiumfreisetzung und Redoxpotential konnte aber nicht gefunden werden. Insgesamt wurden maximal 2 % des vorhandenen Cadmiums freigesetzt. Im Vergleich zu Versuchen mit nicht dotierten Böden, der selbst auch geringe Mengen an Cadmium enthielt, konnte keine erhöhte Freisetzung beobachtet werden. Daraus kann geschlossen werden, dass die Cadmiumpigmente im Boden nur in sehr geringen Maß verfügbar sind