20 research outputs found
Characterization of PAH-contaminated soils focusing on availability, chemical composition and biological effects
The risks associated with a soil contaminated by polycyclic aromatic hydrocarbons (PAHs) are generally assessed by measuring individual PAHs in the soil and correlating the obtained amounts to known adverse biological effects of the PAHs. The validity of such a risk estimation is dependent on the presence of additional compounds, the availability of the compounds (including the PAHs), and the methods used to correlate the measured chemical data and biological effects. In the work underlying this thesis the availability, chemical composition and biological effects of PAHs in samples of soils from PAH-contaminated environments were examined. It can be concluded from the results presented in the included papers that the PAHs in the studied soils from industrial sites were not generally physically trapped in soil material, indicating that the availability of the PAHs was not restricted in this sense. However, the bioavailable fraction of the PAHs, as assessed by bioassays with the earthworm Eisenia Fetida, could not be assessed by a number of abiotic techniques (including: solid phase micro extraction, SPME; use of semi-permeable membrane devices, SPMDs; leaching with various solvent mixtures, leaching using additives, and sequential leaching) and it seems to be difficult to find a chemical method that can accurately assess the bioavailability of PAHs. Furthermore, it was shown that PAH-polluted samples may be extensively chemically characterized by GC-TOFMS using peak deconvolution, and over 900 components can be resolved in a single run. The chemical characterization also revealed that samples that appeared to be similar in terms of their PAH composition were heterogeneous in terms of their overall composition. Finally, single compounds from this large set of compounds, which correlated with different biological effects, could be identified using the multivariate technique partial least squares projections to latent structures (PLS). This indicates that PLS may provide a valid alternative to Effect Directed Analysis (EDA), an established method for finding single compounds that correlate to the toxicity of environmental samples. Thus, the instrumentation and data evaluation tools used in this thesis are clearly capable of providing a broad chemical characterization as well as linking the obtained chemical data to results from bioassays. However, the link between the chemical analyses and the biological tests could be improved as as an organic solvent that solubilised virtually all of the contaminants was used during the chemical analysis while the biological tests were performed in an aqueous solution with limited solubility for a number of compounds. Consequently the compounds probably have a different impact in the biological tests than their relative abundance in profiles obtained by standard chemical analyses suggests. The availability and bioavailability of contaminants in soil also has to be studied further, and such future studies should focus on the molecular interactions between the contaminants and different compartments of the soil. By doing so, detailed knowledge could be obtained which could be applied to a number of different contaminants and soil types. Such studies would generate the data needed for molecular-based modelling of availability and bioavailability, which would be a big step forward compared to current risk assessment practices
Characterization of PAH-contaminated soils focusing on availability, chemical composition and biological effects
The risks associated with a soil contaminated by polycyclic aromatic hydrocarbons (PAHs) are generally assessed by measuring individual PAHs in the soil and correlating the obtained amounts to known adverse biological effects of the PAHs. The validity of such a risk estimation is dependent on the presence of additional compounds, the availability of the compounds (including the PAHs), and the methods used to correlate the measured chemical data and biological effects. In the work underlying this thesis the availability, chemical composition and biological effects of PAHs in samples of soils from PAH-contaminated environments were examined. It can be concluded from the results presented in the included papers that the PAHs in the studied soils from industrial sites were not generally physically trapped in soil material, indicating that the availability of the PAHs was not restricted in this sense. However, the bioavailable fraction of the PAHs, as assessed by bioassays with the earthworm Eisenia Fetida, could not be assessed by a number of abiotic techniques (including: solid phase micro extraction, SPME; use of semi-permeable membrane devices, SPMDs; leaching with various solvent mixtures, leaching using additives, and sequential leaching) and it seems to be difficult to find a chemical method that can accurately assess the bioavailability of PAHs. Furthermore, it was shown that PAH-polluted samples may be extensively chemically characterized by GC-TOFMS using peak deconvolution, and over 900 components can be resolved in a single run. The chemical characterization also revealed that samples that appeared to be similar in terms of their PAH composition were heterogeneous in terms of their overall composition. Finally, single compounds from this large set of compounds, which correlated with different biological effects, could be identified using the multivariate technique partial least squares projections to latent structures (PLS). This indicates that PLS may provide a valid alternative to Effect Directed Analysis (EDA), an established method for finding single compounds that correlate to the toxicity of environmental samples. Thus, the instrumentation and data evaluation tools used in this thesis are clearly capable of providing a broad chemical characterization as well as linking the obtained chemical data to results from bioassays. However, the link between the chemical analyses and the biological tests could be improved as as an organic solvent that solubilised virtually all of the contaminants was used during the chemical analysis while the biological tests were performed in an aqueous solution with limited solubility for a number of compounds. Consequently the compounds probably have a different impact in the biological tests than their relative abundance in profiles obtained by standard chemical analyses suggests. The availability and bioavailability of contaminants in soil also has to be studied further, and such future studies should focus on the molecular interactions between the contaminants and different compartments of the soil. By doing so, detailed knowledge could be obtained which could be applied to a number of different contaminants and soil types. Such studies would generate the data needed for molecular-based modelling of availability and bioavailability, which would be a big step forward compared to current risk assessment practices
Resultat frÄn projektet Testmetodik för behandling av sulfidjord och sur sulfatjord
Försöken visar att sulfidjordar som kalkats av ett aktiv jordbruk, med tillsatt kalk 6 jÀmfört med ej oxiderad sulfidjord.Testmetodik för behandling av sulfidjord och sur sulfatjor
Tester av sulfidjord i stor skala
MTC har för Trafikverkets rÀkning behandlat sulfat- och sulfidjord i fullskaleförsök med elfilterstoft vid MTC testanlÀggning. Syftet med försöken var att utröna möjligheten att stabilisera och/eller neutralisera den svavelhaltiga jorden med mÄlet att den kan ÄteranvÀndas i anlÀggningsÀndamÄl i eller utanför Trafikverkets verksamheter och projekt. Den lÄga variationen av uppmÀtta pH-vÀrden som redovisas över de 5 mÄnaderna som experimentet pÄgick indikerar att ingen betydande försurande effekt kunde noteras frÄn den stabiliserade jorden under den tiden som experimentet pÄgick.Metodik för stabilisering utomhus i verkliga förhÄllanden av sulfidjor
Development of expert system for assessment of crushed rock aggregates\u92 mechanical properties
PÄ uppdrag av Trafikverket kompletterade och vidareutvecklade LuleÄ tekniska universitet/Envix Nord AB i samarbete med VTI expertsystemet för bedömning av bergmaterialens mekaniska egenskaper, baserat pÄ beskrivning av bergartens petrografiska egenskaper. Projektets mÄl Àr att möjliggöra en bedömning av bergmaterialens kvalitet och praktiska anvÀndning i projekteringsstadiet. Projektets första del publicerades som VTI rapport 715. FortsÀttningsprojektets syfte Àr att förbÀttra expertsystemets bedömningssÀkerhet genom tillförandet av kompletterande analysresultat Ätföljda av multivariat utvÀrdering. Projektet genomfördes genom analyser av utvalda kompletterande prov, multivariat utvÀrdering av det kompletterade underlaget samt kvalitetsförbÀttring av bedömningssystemets klassificeringsnycklar. Expertsystemet bygger pÄ 43 utvalda bergmaterial. För den multivariata utvÀrderingen anvÀndes PCA och PLS. Nycklarnas sÀkerhetsnivÄer skÀrptes och inverkan av fler petrografiska parametrar pÄ de mekaniska egenskaperna verifierades. De petrografiska variabler som visade sig ha störst inverkan pÄ de mekaniska egenskaperna för granitoider Àr kornstorlek, kornstorleksfördelning och glimmerhalt. UtvÀrderingen pekade pÄ ett starkt samband mellan glimmerhalt och foliationsgrad, vilket Àven resulterar i en tydlig skillnad mellan massformiga och folierade granitoider. BetrÀffande gabbroider var det mikrosprickfrekvens, glimmerhalt, kornstorleksfördelning och kornstorlek som uppvisade inverkan pÄ de mekaniska egenskaperna. UtvÀrderingen indikerade att metamorfosgraden frÀmst har positiv pÄverkan pÄ kulkvarnsvÀrdet. De lÄgmetamorfa gabbroiderna har bÀttre kulkvarnsvÀrde Àn de magmatiska varianterna. Dock inverkar Àven sÄvÀl glimmerhalt som kornstorlek. Gabbroider med glimmerhalt 5\u96-15 % har bÀttre mekaniska egenskaper Àn de med lÀgre (>5 %). Multivariat utvÀrdering Àr lÀmpligt för att verifiera de mekaniska egenskapernas beroende av flera olika petrografiska egenskaperOn behalf of the Swedish Transport Administration, LuleÄ University of Technology (LTU)/Envix North Ltd and the Swedish National Road and Transport Research Institute (VTI) developed the expert system for evaluation of rock materials' mechanical properties, i.e. an evaluation system based on petrographic parameters. The project aimed to provide a prompt documented evaluation of rock mass quality and its practical use as aggregate, even when rock is covered by drift material. The project's primary outcome has been published in VTI rapport 715. The present project was carried out by analysis of selected samples, multivariate evaluation, and improvement of the expert system's classification keys for granitoids and gabbroids. The system is currently based on 43 selectively chosen rock materials. The multivariate evaluation used PCA and PLS. The correlation (PLS evaluation) between petrographic and mechanical properties shows that for both granitoids and gabbroids, there are generally the same petrographic parameters that affect mechanical properties. The petrographic parameter for the granitoids having the greatest impact on the mechanical properties are: grain size, grain size distribution and mica content. The analysis also indicated a strong correlation between mica content and degree of foliation, which in turn results in a clear difference between magmatic and metamorphic granitoids. Concerning the gabbroids, it was frequency of micro fractures, mica content, grain size, and grain size distribution that had the greatest impact on the mechanical properties. The analysis indicated that the degree of metamorphism affects the resistance to abrasion from studded tires. Low metamorphic gabbroids show generally \u93lower\u94 (better) Nordic ball mill values, compared to rocks of \u93higher\u94 degree of metamorphism. Mica in gabbroids generally has a positive effect (more competent) on mechanical properties. Rock samples with \u93higher\u94 mica content (5\u96-15%) generally have better mechanical properties than those with lower (>5%) mica content. The multivariate evaluation has proven to be a suitable tool to verify the mechanical properties' dependence on petrographic parameters
Vertical and Lateral Redistribution of POPs in Soils Developed along a Hydrological Gradient
Study of the dispersion of persistent organic pollutants (POPs) throughout the environment is necessitated by their toxicological properties and propensity to accumulate in biota. In this study, we use data from the analysis of three <sup>210</sup>Pb dated soil profiles collected along a 30-m hydrological gradient to demonstrate postdepositional mobility of polychlorinated dibenzo-<i>p</i>-dioxins and polychlorinated dibenzofurans (PCDD/Fs) and polychlorinated biphenyls (PCBs). We found that (i) humus originating from litter exposed to surface fallout during the 1960â1970s contains the highest concentrations of PCDD/Fs and PCBs in the O-horizon of the soils; (ii) accumulation rates of PCDD/Fs and PCBs in the O-horizon (âŒ5.0 and âŒ210 ÎŒg m<sup>â2</sup> yr<sup>â1</sup>) constituted only 9.1% and 3.5%, respectively, of the measured annual input, demonstrating that a minor fraction of the deposited material is retained within the O-horizon; (iii) POP inventories in the upper 0.5â0.9 m of the mineral soil constituted a considerable part (40â70%) of the total pool stored in the soil, implying significant vertical translocation of atmospheric derived POPs; and (iv) increasing downslope inventories of POPs suggest a lateral downward transport of POPs from uphill soils. The findings challenge the commonly accepted view that POPs fallout is effectively retained within O-horizons
The impact of hydrothermal carbonization on the surface functionalities of wet waste materials for water treatment applications
Hydrothermal carbonization (HTC) is an energy-efficient thermochemical process for converting wet waste products into value added materials for water treatment. Understanding how HTC influences the physicochemical properties of the resultant materials is critical in optimizing the process for water treatment, where surface functionality and surface area play a major role. In this study, we have examined the HTC of four wet waste streams, sewage sludge, biosludge, fiber sludge, and horse manure at three different temperatures (180 degrees C, 220 degrees C, and 260 degrees C). The physicochemical properties of these materials were examined via FTIR, SEM and BET with their adsorption capacity were assessed using methylene blue. The yield of solid material after hydrothermal carbonization (hydrochar) decreased with increasing temperature for all samples, with the largest impact on horse manure and fiber sludge. These materials also lost the highest degree of oxygen, while HTC had minimal impact on biosludge and sewage sludge. The differences here were due to the varying compositions of each waste material, FTIR identified resonances related to cellulose in horse manure and fiber sludge, which were not detected in biosludge and sewage sludge. Adsorption capacities varied between 9.0 and 68 mg g(-1) with biosludge HTC at 220 degrees C adsorbing the highest amount. Adsorption also dropped drastically at the highest temperature (260 degrees C), indicating a correlation between adsorption capacity and HTC conditions. This was attributed to the loss of oxygen functional groups, which can contribute to adsorption. These results suggest that adsorption properties can be tailored both by selection of HTC temperature and feedstock.Bio4Energ
Persistent Organic Pollutants in Streamwater: Influence of Hydrological Conditions and Landscape Type
Concentrations of polychlorinated dibenzo-p-dioxins and dibenzofurans (PCDD/Fs), polychlorinated biphenyls (PCBs), and hexachlorobenzene (HCB) in streamwater were measured in a remote catchment in northern Sweden and downstream to the Baltic Sea. Sampling took place at seven sites during two years and under different hydrological conditions: during the snow-free, snow-covered, and spring-flood seasons. Concentrations varied substantially between seasons and were up to 20 times higher during the spring flood compared to the preceding snow-covered period. The increase in concentrations with runoff was due to higher levels of particle-associated contaminants, while the dissolved concentrations remained stable. Particulate-contaminant concentrations were positively correlated primarily to suspended particulate matter (SPM) at sites in areas with a high land-cover fraction of sorted sediment. When upstream sampling locations were compared, a mire-dominated stream had higher concentrations and a lower retention of atmospherically deposited contaminants than a forest stream of the same catchment size. Contaminant concentrations (normalized to volume) did not increase consistently downstream despite the presence of several point sources. However, when normalized to the amount of SPM, concentrations were on average >20 times higher at the outlet in the Baltic Sea compared to the outlet from the remote catchment without point sources
The fate of per- and polyfluoroalkyl substances within a melting snowpack of a boreal forest
Per- and polyfluoroallcyl substances (PFAS) were measured systematically in a snowpack in northern Sweden to determine chemical behaviour during seasonal melt. Average PFAS concentrations were generally low, but displayed a wide range with median (range) concentrations of PFOA and PFOS of 66.5 pg L-1 (ND-122) and 20.5 pg L-1 (2.60-253) respectively. Average concentrations of the shorter chain, C4 and C5 perfluoroalkyl carboxylates (PFCAs) and perfluoroalkyl sulfonates (PFSAs), were similar to 10-fold higher. Differences in the PFAS concentrations and profile were observed between surface snow and deeper layers, with evidence of PFAS migration to deeper snow layers as melt progressed. Chemical loads (ng m(-2)) for C4-9 PFCAs decreased gradually as melt progressed, but increased for C-4, C6-8 PFSAs and the longer chain C10-12 PFCAs. This enrichment in the diminishing snowpack is an unusual phenomenon that will affect PFAS elution with meltwater and subsequent entry to catchment surface waters. (C) 2014 Elsevier Ltd. All rights reserved
SNOWMAN - MCA: Multi-criteria analysis of remediation alternatives to access their overall impact and cost/benefit, with focus on soil function (ecosystem services and goods) and sustainability
This final report summarises major activities, results and conclusions derived within the SNOWMAN-MCA project. The main objective of the SNOWMAN-MCA project (2009-2013) was to demonstrate the use of multi-criteria analysis (MCA) in evaluating land management and soil remediation alternatives to access their overall impact on sustainability, with focus on soil functions and soil services. Soil functions are critical for ecosystem survival and for ecosystemsâ provision of services to humans, and maintained soil function is a key parameter in sustainable development. The SNOWMAN-MCA project was based on studies of three representative polluted sites in Sweden and Austria, and included a range of conventional and innovative remediation scenarios. Key results of the SNOWMAN-MCA project include:âą A suggested hierarchy between soil functions, soil processes, soil services and ecosystem services, resulting in a set of soil function related ecological, socio-cultural and economic criteria and sub-criteria to be used in MCA.âą A suggested minimum data set (MDS) of soil quality indicators for soil function evaluation, and a software tool (SF Box) for calculating changes in soil quality based on the proposed MDS.âą A suggested structured and transparent approach for incorporating soil function and soil use aspects into sustainability appraisal of remediation alternatives using MCA.Using input from research carried out in tandem with the SNOWMAN-MCA project, the impact of remediation in the ecological, socio-cultural and economic domain was further assessed, including suggested criteria for the socio-cultural domain and research on how uncertainty may be addressed in MCA. Based on this research and on previous efforts (Ros\ue9n et al., 2009), an MCA software tool (SCORE) was developed, and used for evaluating the sustainability of suggested remedial actions at the studied sites. The results from the SCORE tool are in this report presented together with the results of the SNOWMAN-MCA project, demonstrating a holistic approach to sustainable remediation