Karlson, U. G.

Mayer, P.

Rein, Arno

Smith, K. E. C.

Trapp, Stefan

Polycyclic aromatic hydrocarbons (PAHs) in the environment are to a major degree bound to organic matter or soot particles. It is disputed whether and to which extent the adsorbed fraction of PAH in soil and sediment can be attacked by microbial enzymes, or whether dissolution in aqueous media is required. In that case, the degradation depends critically on the bioavailability, or better the bioaccessibility of PAH for microbes. The increasing non-accessibility of PAH with time (‘aging’) may explain the formation of a residual fraction, which has been observed in remediation projects. A unified model for sorption, sequestration and degradation of neutral organic compounds in soils and sediments has been developed and tested (see also Trapp et al. session J01). Adsorption was considered as a two-phase process, with rapid and slow adsorption rates. Calculated or experimental sorption rates and kinetic data for growth and metabolism of PAH-degrading bacteria were obtained as input parameters. The model simulations were compared to existing solutions (such as the Best equation) and to experimental results. With this new model approach, a range of experimental observations available in literature could be simulated, encompassing various soil types and PAHs, and different bacterial strains. Own experiments are currently performed on phenantrene, fluoranthene and other PAHs and on ad/desorption as well as on biodegradation. The results shall be used to calibrate and verify the new model approach. The model was also used to simulate typical scenarios of adsorption (aging) and microbial degradation, in order to identify sensitive parameters and processes. Furthermore, the impact of dissolved organic matter and various types of amendments was studied, which potentially enhance diffusive mass transfer and biodegradation performance. The final goal is to optimize remediation options

Online Research Database In Technology

                       General rights Copyright and moral rights for the publications made accessible in the public portal are retained by the authors and/or other copyright owners and it is a condition of accessing publications that users recognise and abide by the legal requirements associated with these rights.  • Users may download and print one copy of any publication from the public portal for the purpose of private study or research. • You may not further distribute the material or use it for any profit-making activity or commercial gain • You may freely distribute the URL identifying the publication in the public portal   If you believe that this document breaches copyright please contact us providing details, and we will remove access to the work immediately and investigate your claim.     Downloaded from orbit.dtu.dk on: Dec 19, 2017Modeling experimental findings on sorption and biodegradation of PAHsRein, Arno; Smith, K. E. C.; Karlson, U. G.; Mayer, P.; Trapp, StefanPublished in:SETAC Europe 21st Annual Meeting Abstract BookPublication date:2011Document VersionPublisher's PDF, also known as Version of recordLink back to DTU OrbitCitation (APA):Rein, A., Smith, K. E. C., Karlson, U. G., Mayer, P., & Trapp, S. (2011). Modeling experimental findings onsorption and biodegradation of PAHs. In SETAC Europe 21st Annual Meeting Abstract Book230 SETAC Europe 21st Annual Meeting Abstract Booksorption behaviour of four different PAHs (pyrene, phenanthrene, fluoranthene and fluorene) with solid-phase NOM and BC and the effect of rhamnolipid biosurfactants on sorption equi-librium  Biosurfactants sorption was also determined  Biodegradation of sorbed PAHs in the absence and presence of biosurfactants was also followed using a representative PAH-degrading soil bacterium (Mycobacterium gilvum VM552)  Experimental conditions included different sources of NOM and BC and different solid-aqueous phase ratios  The results showed that bio-surfactants, especially when they were present at levels above CMC, often promoted desorption and biodegradation of PAHs WE 214 Modeling experimental findings on sorption and biodegradation of PAHs A Rein1, KEC Smith2, UG Karlson2, P Mayer2, S Trapp1 1Technical University of Denmark, KGS  LYNGBY, Denmark 2Aarhus University / National Environmental Research Institute, ROSKILDE, Denmark Polycyclic aromatic hydrocarbons (PAHs) in the environment are to a major degree bound to organic matter or soot particles  It is disputed whether and to which extent the adsorbed fraction of PAH in soil and sediment can be attacked by microbial enzymes, or whether dissolution in aqueous media is required  In that case, the degradation depends critically on the bioavailability, or better the bioaccessibility of PAH for microbes  The increasing non-accessibility of PAH with time (‘aging’) may explain the formation of a residual fraction, which has been observed in remediation projects  A unified model for sorption, sequestration and degradation of neutral organic compounds in soils and sediments has been developed and tested (see also Trapp et al  session J01)  Adsorption was considered as a two-phase process, with rapid and slow adsorption rates  Calculated or ex-perimental sorption rates and kinetic data for growth and metabolism of PAH-degrading bacteria were obtained as input parameters  The model simulations were compared to existing solutions (such as the Best equation) and to experimental results  With this new model approach, a range of experimental observations available in literature could be simulated, encompassing various soil types and PAHs, and different bacterial strains  Own experiments are currently performed on phenantrene, fluoranthene and other PAHs and on ad/desorption as well as on biodegradation  The results shall be used to calibrate and verify the new model approach  The model was also used to simulate typical scenarios of adsorption (aging) and microbial degradation, in order to identify sensitive parameters and processes  Furthermore, the impact of dissolved organic matter and various types of amendments was studied, which potentially enhance diffusive mass transfer and biodegradation performance  The final goal is to optimize remediation options WE 215 Sorption and desorption characteristics of two insecticides (chlordecone and cadusafos) previously used in banana plantations of the French West Indies JD Fernandez-Bayo1, C Saison1, C Geniez1, AE Berns2 1Laboratoire d’étude des Interactions Sol - Agrosystème - Hydrosystème, MONTPELLIER, France 2Forschungszentrum Juelich GmbH, Inst Bio- and Geosciences, IBG 3: Agrosphere, JUELICH, Germany Chlordecone (CLD) is a highly persistent organochlorine pesticide that was used for a wide range of pests around the world, among them, the banana weevil Cosmopolites sordidus in planta-tions of the French West Indies  It was banned in France in 1993  One of the molecules that replaced it was cadusafos, an organophosphate that has since then been removed from the market in the European Union in 2008  Nearly 20 years after its prohibition, CLD is still detected in ev-ery compartment of the environment, i e  in soils, surface and groundwaters and some agricultural products and it is suspected to increase the prevalence of prostate cancers in exposed populations  The physico-chemical characteristics of this molecule along with its high stability due to the numerous chlorinated groups that protect the molecule from degradation, make sorption one of the most important processes that govern the fate of chlordecone in soils  However, the literature in the environmental fate of this molecule is scarce and mainly from the 80’s or earlier  The aim of this work is to improve the knowledge in the sorption and desorption of CLD and cadusafos in tropical volcanic soils of the French West Indies  Sorption-desorption isotherms were carried out in batch experiments in 7 different soils and fitted to the Freundlich model  Additionally, the nature of the soil organic matter, known to be one of the determinants of the adsorption of pesticides, was examined by 13C-CP MAS NMR  Sorption of CLD in soils was very high (26< Kf < 102 L kg-1) with a high hysteresis effect in 5 of the soils studied and no desorption at all in the two remaining soils  Freundlich’s Kf parameter of cadusafos was ranging between 0 8 and 21 L kg-1 and contrarily to CLD, desorption was not showing a high degree of hysteresis  The Kf values were correlated to the OC content (P<0 01) for both molecules and derived Koc were ranging between 1200 and 2500 L kg-1 for CLD and between 67 and 135 L kg-1 for cadusafos  Despite the different nature of the soils, NMR spectra for soil organic matter were very similar between the 7 studied soils  Thus, the Koc heterogeneity is not only influenced by the chemistry of the organic matter, but must also be attributed to other soil properties  In the literature, values on the Koc of CLD were missing, they were sparse for cadusafos and they represent a necessary piece of information for the use of models to predict the transfer of these molecules in surface and groundwaters WE 216 On the challenge to remediate a soil contaminated with crystalline DDT by activated char-coal A Younas1, I Hilber2, M Khwaja3, TD Bucheli2 1Environmental Science Department, PESHAWAR, Pakistan 2Agroscope Reckenholz Tanikon Research Station ART, ZURICH, Switzerland 3Sustainable Policy Development Institute, ISLAMABAD, Pakistan The production and distribution of the insecticide dichlorodiphenyltrichlorethane (DDT) resulted in a polluted area of about 85 hectares at Nowshera, Khyber Pakhtunkhwa (KPK), Paki-stan  At the factory’s place the contamination is up to 800 g/kg DDT in dry soil  To reduce DDT exposure of the environment and humans, this contaminated site has to be remediated  Therefore, the aim of this joint research project is to test a remediation strategy with activated charcoal (AC) added to substantially reduce the bioavailable fraction of the aged DDT in the soil  To the best of our knowledge, AC has been used for remediation purposes in a concentration range of ppb to ppm in soils and sediments, but never in the percent range  Under these circumstances, limitations are set at extremes and are manifold  Results from this study will give important information on the performance of AC materials in a naturally contaminated soil and reveal the influence of soil treatment on the immobilization of DDT  Pots with five kg of field soil were placed in the laboratory  Then, 2 % and 10 % GAC and 0 1 % and 2 % PAC were added  To test the influence of different soil treatments on the binding quality of the AC, the amended soil was then treated in three different ways  Some pots were watered during a month to simulate monsoon season, but left untreated for the following five months (treatment 0)  Others were mixed fortnightly to simulate ploughing (treatment P) and a third group was subjected to regularly watering (treatment W) and watering and ploughing (treatment PW) over the whole period of time  After certain time periods, bioavailable DDT and metabo-lites were assessed by six hours Tenax® extractions with two grams of Tenax® beads and one gram of dry soil  Results from this experiment were surprising  The Tenax® extractable DDT decreased drastically over time not only in all AC amendments and treatments, but also in the control  After 150 days, the concentration of the DDT extracted by Tenax® was very low with a few per milles  Overall, two main questions arise under this situation with extremely high DDT concentrations: 1) is Tenax® the appropriate tool to assess the bioavailability, and 2) is AC amendment capable to sub-stantially reduce DDT exposure  These important issues will be addressed in this presentation WE 217 Distribution of aged 14C-atrazine residues in soil following 22 years of environmental exposure. Y Andreou Cyprus University of Technology, LIMASSOL, Cyprus Distribution and localisation of pesticide residues into the different physical fractions of soil may reveal information on processes taking place in soil  Soils amended with 14C-atrazine, were aged for 22 years under environmental conditions in a lysimeter in Germany  The soil was sampled and subjected to physical and chemical fractionation before and after incubation with the earthworm Apporectodea caliginosa for 7 days  No significant change in the soil physical and chemical fractionation of the 14C-atrazine residues and organic carbon was observed in this study as a consequence of the activity of the A  caliginosa  The low organic carbon of the soil, the absence of relatively fresh organic matter and the long ageing time might explain the limited bioavailability of the 14C-atrazine to the earthworm  Approximately 9% of the applied 14C-atrazine associated activity was found to be present in the top soil layer 0-10 cm of the lysimeter  This amount repre-sented approximately 36% of the total amount of 14C-atrazine associated activity presented in the soil after 22 years of environmental ageing  Soil half lives calculated in this study taking into account the non-extractable 14C-atrazine residues were much greater than those reported from previous studies  This finding is of particular importance given that the soil used here was aged under natural environmental conditions compared to laboratory studies WE 218 Use of solid-phase microextraction and toxicity tests to determine the bioavailability and toxicity of hetero-PAH with the oligochaete Lumbriculus variegatus in sediment-pore water systems AJ Schneider1, TB Seiler2, K Schmidt3, G Witt3, B Schmidt2, A Schäffer2, H Hollert2 1RWTH Aachen University/Institute for Environmental Research, AACHEN, Germany 2RWTH Aachen University, Institute for Environmental Research, AACHEN, Germany 3Hamburg University of Applied Sciences (HAW), Faculty of Life Sciences, HAMBURG, Germany Polyaromatic heterocycles (hetero-PAH) are N-, S-, O- substituted polyaromatic hydrocarbons (PAH)  They occur together with their unsubstituted analoga e g  at creosote-contaminated sites  Their acute, chronic and reproduction toxicity as well as their higher water solubility compared to their unsubstituted parent compounds account for their ecotoxicolgical relevance  In the present study the chronic toxicity of two hetero-PAH acridine (AC) and xanthene (XA) in a sediment-pore water system of a spiked natural river sediment (Altrip, Rhein, Worms; AC 6 3-146 2 µg/g DW; XA 0 1-270 µg/g DW) on the reproduction of sediment dwelling endoben-thic oligochaetes Lumbriculus variegatus was determined according to OECD guideline 225  In parallel to chronic toxicity, the freely dissolved pore water concentrations (cfree) of the substances were determined by solid-phase micro extraction (SPME) and high performance liquid chroma-tography  Determined effect concentrations (ECx) for the reproduction of L. variegatus were based on the total sediment concentration (EC50 AC 37 8 µg/g DW, EC50 XA 2 4 µg/g DW), the tissue concentration (EC50 AC 0 0052 µg/mg DW tissue) and cfree (EC50 AC 0 034 µg/ml)  Hormesis was observed for the reproduction of L.variegatus at the lowest tested concentrations of both substances  Furthermore, with the SPME technique it was possible to determine cfree of both substances in sediment pore water at higher sediment concentrations (AC ≥ 30 5 µg/g DW and XA ≥90 µg/g DW) and to prove metabolic degradation of xanthene to xanthone in the sedi-ment  In contrary, no degradation of acridine to acridone was detected in both, the sediment and L. variegatus  The results emphasize, that for sediment contact tests, i e , testing the ecotoxicity of hydrophobic organic chemicals (log KOW < 5 7) on endobenthic organisms, it is important to simultaneously determine cfree of the substances to be able to link the observed ecotoxic effects to the real expo-sure WE 219 Characterizing the bioavailability of cationic surfactant using passive sampler Y Chen1, STJ Droge2, JLM Hermens1 1Institute for Risk Assessment Sciences, UTRECHT, The Netherlands 2Helmholtz Centre for Environmental Research-UFZ, LEIPZIG, Germany Cationic surfactants are ubiquitous contaminants that are extensively detected in sediment, sew-age sludge or surface water due to their wide applications in industrial and domestic products  However, the understanding of the impact of this class of compounds on the environment is still limited  The freely dissolved concentration of an organic compound is an important parameter for accessing the environmental fate and bioavailability of the chemical  The free concentration of cationic surfactants, are difficult to determine because of their high adsorptive capacity to lab ap-paratus and because the difficulty to separate the bound particles from the aqueous phase  In the current study, a solid phase microextraction (SPME) method was optimized and applied to characterize the bioavailability of two cationic surfactants, hexadecyl trimethyl ammonium chloride (IV-16) and benzyl dimethyl dodecyl ammonium chloride (C12-BAC)  The effect of solution chemistry on the sorption isotherm to SPME was first examined  Sorption experiments of the two cationics to Pahokee peat and humic acid were carried out  The influence of pH and the presence of inorganic cations on the sorption behavior were examined within the range of relevant environmental concentrations  The results suggest both ionic and nonionic interactions could play a role in the sorption process for cationic surfactants WE 220 Sorption of cationic organic compounds: how important is clay compared to organic mat-

Modeling experimental findings on sorption and biodegradation of PAHs

http://orbit.dtu.dk/ws/files/6332080/prod21323971136211.p230__AM11_abstract_book__Rein_etal_2011.pdf

Modeling experimental findings on sorption and biodegradation of PAHs

Abstract

Similar works

Full text

Available Versions

Online Research Database In Technology