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- Liquid-liquid extraction (3)
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- Batch test (1)
- Batch tests (1)
- Contaminated soil (1)
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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.
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%.
Monitoring of PAH in aqueous samples - a comparison of different sample preparation techniques
(2011)
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.