Filtern
Dokumenttyp
Sprache
- Englisch (17) (entfernen)
Schlagworte
- Column test (5)
- Leaching (5)
- Batch test (4)
- Batch tests (3)
- Liquid-liquid extraction (3)
- Artificial turf (2)
- Column tests (2)
- Complex aqueous matrix (2)
- PAH (2)
- Stir bar sorptive extraction (2)
The risk assessment of total petrol hydrocarbons (TPH) and polycyclic aromatic hydrocarbons (PAH), two of the most frequent soil and water contaminants, has to include their exposure pathways, especially the soil groundwater pathway. Threshold values have to be aquired for the amendment to the German Federal Soil Protection Contaminated Sites Ordinance. For this purpose, a batch experiment with a liquid to solid ratio (L/S) of 2 L/kg was developed. Aim of this work was to verify the robustness of this leaching procedure for TPH and PAH in different soil types against varying test conditions. Also, stir bar sorptive extraction (SBSE) was tested as alternative sample preparation of eluates for PAH analysis.
Sulfonamides (SAs) and their metabolites present severe hazards to human health and the environment, mainly because of antibiotic resistance. Knowledge of their bioavailability, including their sorption to soils and their impact on the soil-groundwater pathway, is crucial to their risk assessment. Laboratory batch and column leaching tests are important tools for determining the release potential of contaminants from soil or waste materials. Batch and column tests were carried out with soils differing in particle size distribution, organic matter content and pH, each spiked with sulfonamides (sulfadimethoxine (SDM), sulfaguanidine (SGD), sulfisoxazole (SX)). In order to test the applicability of leaching tests to polar contaminants batch and column tests were also compared. In the column tests, release was found to depend on the properties of both soil and sulfonamides. The fastest release was observed for coarse-grained soil with the smallest organic matter content (MS soil; 100% decrease in concentration until liquid-to-solid ratio (L/S) of 0.9 L kg-1 for all SAs). The slowest release was established for sulfadimethoxine (24.5% decrease in concentration until L/S 1.22 L kg-1). The results of the batch and column tests were comparable to a large extent, with slightly higher concentrations being obtained in the column test experiments of fine-grained soils with a high organic matter content.
Synthetic athletic tracks and turf areas for outdoor sporting grounds may release contaminants due to the chemical composition of some components. A primary example is that of zinc from reused scrap tires (main constituent, styrene butadiene rubber, SBR), which might be harmful to the environment. Thus, methods for the risk assessment of those materials are required. Laboratory leaching methods like batch and column tests are widely used to examine the soil–groundwater pathway. We tested several components for artificial sporting grounds with batch tests at a liquid to solid (LS) ratio of 2 L/kg and column tests with an LS up to 26.5 L/kg. We found a higher zinc release in the batch test eluates for all granules, ranging from 15% higher to 687% higher versus data from column tests for SBR granules. Accompanying parameters, especially the very high turbidity of one ethylene propylene diene monomer rubber (EPDM) or thermoplastic elastomer (TPE) eluates, reflect the stronger mechanical stress of batch testing. This indicates that batch test procedures might not be suitable for the risk assessment of synthetic sporting ground components. Column tests, on the other hand, represent field conditions more closely and allow for determination of time-dependent contaminants release.
Stir bar sorptive extraction (SBSE) is an equilibrium extraction method used amongst others for the analysis of polycyclic aromatic hydrocarbons (PAH) in aqueous samples. We compared SBSE to liquid–liquid extraction (LLE) for aqueous eluates obtained from batch and column tests of PAH contaminated soils to check whether SBSE might be considered as an alternative sample preparation method. We used soils with different particle size distribution, organic matter content, and resulting eluate turbidity to test the sample preparation methods on eluates with matrices of varying complexity. Furthermore, we studied the influence of diluted organic matter (DOM) on the PAH sorption process to the polymer coating of the stir bar during SBSE. In the majority of cases, we found higher PAH concentrations (up to 288%) with SBSE than with LLE. The turbidity correlates with the difference in PAH results, i.e. the greater the turbidity in the eluate, the more PAH we found with SBSE compared to LLE. We observed no similar trend regarding the amount of total organic carbon (TOC). The presence of DOM in the eluate seems to hamper the SBSE slightly, the PAH recovery varied between 82 and 104%.
Scrap tyres are widely reused in the form of granules as infill materials or component of sub-base layers in construction of sporting grounds such as synthetic turf areas and athletic track surfaces. The recycled rubber may contain organic and inorganic pollutants due to the presence of vulcanisation catalysts, stabilisers and other additives which can be released into soil and groundwater in the case of outdoor sports facilities. In order to evaluate the amount of potentially mobile pollutants, leaching tests can be employed. This study aimed particularly at the investigation of the feasibility of column tests using complete synthetic surface flooring or turf system assemblies. The release of zinc and polycyclic aromatic hydrocarbons (PAH) leached from components of sports surfaces containing recycled rubber granules was considered. Additionally, batch tests on coated and uncoated styrene butadiene rubber (SBR) granules aged by artificial weathering were performed to indicate its possible influence on the leaching behaviour of zinc and PAH. The chosen approach of column tests simulating typical complete synthetic sports surface installations has been proven to be feasible and robust. The time-dependent leaching behaviour and interactions between single components can be evaluated by column tests. Zinc was the most relevant contaminant in the eluates and its leachability was enhanced after accelerated ageing by artificial weathering. Leachable PAH were found in relatively low but well detectable amounts which increase by ageing as well.
In order to estimating the amount and kind of emissions from polymeric sporting tracks a laboratory test was developed in BAM that combines artificial weathering and subsequent batch and column tests [1, 2, 3]. The goal consisted in nvestigating a possible change of emissions into soil and groundwater of a new sporting ground as a function of ageing and egradation of the system. At various stages of the weathering, the samples were removed and subjected to especially designed column extraction tests for the solid samples. Both these extracts and the accumulated rainwater run-off of the weathering device were subjected to analytical tests of their ingredients. The overall aim of the test consisted in developing ontrollable, reproducible, and standardisable conditions and methods of investigation that would allow an estimation of the emissions in the course of outdoor application of about five years.
Leaching experiments on the release of heavy metals and PAH from C&D waste and MSWI bottom ash
(2010)
Leaching tests are fundamental tools for the assessment of long-term impact of
contaminated waste materials on the soil-groundwater pathway. Waste materials should be
tested under conditions equal to their actual application in re-use scenarios to achieve reliable
results. Since the standards for leaching procedures available on international level so far are
either not validated or considered inadequate in respect to coarse grained materials, new
standards had to be developed. Therefore column percolation and batch test procedures have
been standardized and validated to enable their introduction to new German regulations
concerning waste management. Practical aspects of the test procedures as well as the
boundary conditions compared to the already existing standards will be described. Examples
including round robin test results will be given to justify the selection of the new
specifications.
Leaching tests are fundamental tools for the assessment of long-term impact of contaminated waste materials on the soil-groundwater pathway. Experiments were carried out in the framework of standardization and validation of column percolation and batch test procedures, in particular concerning the stipulation of the experimental setup. The colloid release of column and batch experiments was compared and the influence of different column filling heights (12.5–50 cm) on the release of polycyclic aromatic hydrocarbons (PAH) from soil was studied, as well as the effect of varying contact times (2.5–16 h) on the release of chromium from construction and demolition (C&D) waste and municipal solid waste incineration (MSWI) bottom ash. The results indicate that filtration of the eluate, which is required for batch tests, does not always allow the simulation of the actual colloid amount in soil pore water. Medium column heights four times the inner diameter of the column seemed to provide reasonable equilibrium adjustment conditions and avoid major biodegradation. The release of chromium was only marginally affected by the contact time, varied between 0.115 and 0.150 mg/kg for demolition waste eluate at a liquid-to-solid ratio of approximately 5 L/kg.