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Spatial modeling in sediments /Danielsson, Åsa, January 1900 (has links)
Diss. (sammanfattning) Linköping : Univ. / Härtill 5 uppsatser.
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Salinity Inference In Inland Turkish Shallow Lakes On Paleoecology Using Sub-fossil CladoceraCakiroglu, Ayse Idil 01 February 2013 (has links) (PDF)
In the current study, sub-fossil Cladocera collected from the surface sediment of 44 shallow lakes spanning over five latitudes from north to south of Turkey using snap-shot methodology revealed strong impact of salinity on cladoceran community structure. To see the whole picture, sediment cores collected from six of the lakes and long-term monitoring data from two of the lakes were also investigated.
Contemporary cladocerans and sub-fossil assemblages were compared to reveal that their responses to salinity changes were highly similar. This lead us to use sub-fossil cladocerans and salinity data from water column together while generating the calibration data set using ordination techniques. Salinity transfer function models were developed utilising weighted averaging techniques. The developed salinity transfer function was applied to cladocera assemblages from dated sediment cores. Hindcasting of the salinity inference model was performed using monitoring data and the reconstructed salinities from two central Anatolian lakes and reflected good linear correlation with the known lake salinity history.
This thesis has confirmed that sub-fossil Cladocera is a valuable indicator of historical salinity change and marker for the monitoring of lakes. For the first time, the lake environmental variables and sub-fossil cladoceran species composition from the surface sediments of Turkish shallow lakes were studied and a salinity transfer function was developed to elucidate past salinity change. The approach of the current study has been proven to be reliable while interpreting past salinity conditions. Since monitoring programmes are scarce in Turkey, paleolimnological analyses would be beneficial especially when defining effective restoration strategies.
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Procena remedijacionog potencijala sedimenta zagađenog prioritetnim organskim zagađujućim materijama / Investigation of remediation potential of sediment polluted with priority organic pollutantsGrgić Marko 16 August 2019 (has links)
<p>Predmet istraživanja ove doktorske disertacije je procena potencijalno biodostupne frakcije odabranih prioritetnih organskih polutanata (pentahlorbenzena, heksahlorbenzena, lindana, trifluralina, 4-oktilfenola i 4-nonilfenola) u sedimentu, ispitivanje biodegradacionog potencijala ovih jedinjenja u sedimentu u različitim uslovima, kao i procena potencijala stabilizacije<br />sedimenta dodatkom ugljeničnih sorpcionih agenasa. U cilju razvoja metoda za određivanje biodostupnosti odabranih organskih polutanata ispitivane su i optimizovane metode višestepene i jednostepene parcijalne ekstrakcije primenom sledećih hemijskih agenasa: Tenaks smole, XAD-4 smole i rastvora ciklodekstrina (2-hidroksipropil-β-ciklodekstrina, β-ciklodekstrina i metil-β-ciklodekstrina). Optimalni agens za procenu biodostupne frakcije odabranih organskih zagađujućih materija sa sedimenta XAD-4 smola, a optimalno vreme ekstrakcije primenom jednostepenih ekstrakcija je oko 8 h. Procena biodegradacionog potencijala odabranih prioritetnih organskih zagađujućih materija u sedimentu ispitana je u različitim aerobnim i anaerobnim uslovima uz optimizaciju uslova putem biostimulacije i bioaugmentacije. Pokazano je da svih šest odabranih jedinjenja poseduju značajan potencijal biodegradacije u anaerobnoj sredini pri čemu u slučaju lindana i trifluralina dolazi do potpunog uklanjanja biodostupne količine jedinjenja primenom sva četiri ispitana inokuluma. Aerobni potencijal u ispitanim uslovima pokazali su samo alkil fenoli, gde je takođe uklonjena skoro celokupna količinabiodostupne frakcije jedinjenja u sedimentu (78-85%). Potencijal remedijacije sedimenta dodatkom ugljeničnih materijala ispitan je sa aspekta odabira ugljeničnih sorpcionih agenasa (aktivni ugalj, biougalj i humus); određivanja optimalne količine materijala; isptivanja dugoročnih i kratkoročnih efekata dodatka ovih agenasa na biodostupnost organskih zagađujućih materija kako bi se ispitao efekat starenja i toksičnosti dobijenih smeša. Rezultati stabilizacije zagađujućih supstanci u sedimentu pokazuju da: (1) povećanje doze sva tri sorpciona agensa dovodi do povećanja efikasnosti imobilizacije i smanjenja biodostupne frakcije odabranih organskih jedinjenja; (2) starenjem smeša sedimenta i sorbenata u toku prvih 90 dana dolazi do daljeg smanjenja biodostupne frakcije svih jedinjenja, nakon čega se biodostupna koncentracija ispitivanih jedinjenja primenom aktivnog uglja ne menja, dok primenom biouglja i humusa dolazi do porasta biodostupne frakcije jedinjenja. Testovi fitotoksičnosti su pokazali da je <em>Zea mays </em>akumulirao značajno veće količine ispitivanih jedinjenja iz netretiranog sedimenta u poređenju sa <em>Cucurbita pepo</em> i <em> Lactuca sativa. </em>Toksičnost smeša sedimenta sa aktivnim ugljom i humusom procenjena na osnovu inhibicije luminiscencije na <em>Vibrio fischeri</em> kao i ispitivanjem <em>Zea mays </em>germinacije i produkcije biomase je pokazala značajno smanjenje u odnosu na netretirani sediment. Akumulacija ispitivanih jedinjenja u biomasi <em>Zea mays </em>u netretiranom sedimentu je bila značajno veća u odnosu na sve smeše sedimenta i aktivnog uglja i humusa. Sva tri sorbenta pokazala su veliki remedijacioni potencijal za sediment zagađen organskim zagađujućim supstancama, ali je aktivni ugalj pokazao najbolje performance.</p> / <p>The aim of the research in this PhD dissertation is the assessment of the potentially biodegradable fraction of selected organic pollutants (pentachlorbenzene, hexachlorobenzene, lindane, trifluraline, 4-octylphenol and 4-nonylphenol) in the sediment, estimation of the biodegradation potential of these compounds in sediment in different conditions, as well as the assessment of the stabilization potential sediment by the sediment amendment with of carbon rich sorption agents. In order to develop and optimise methods for the bioavailability assessment of the selected organic pollutants, methods of multistage and single-step non exhaustive extraction were studied using the following chemical agents: Tenax resin, XAD -4 resin and a cyclodextrin solution (2-hydroxypropyl- β-cyclodextrin, β-cyclodextrin and methyl-β-cyclodextrin). Results showed that optimal agent for estimating the bioavailable fraction of selected organic pollutants from the sediment is XAD-4 resins, and that the optimum extraction time using single-step extraction is about 8 h. The assessment of the biodegradation potential of selected priority organic pollutants in the sediment was examined in various aerobic and anaerobic conditions, with the optimization of conditions through biostimulation and bioaugmentation. It has been shown that all six selected compounds possess significant biodegradation potential in the anaerobic environment, where in the case of lindane and trifluraline there is complete removal of the bioavailable amount of the compound using all four inoculum tested. Aerobic potential under the applied conditions has been showen only for alkyl phenols, where almost all of the bioavailable fraction of the compound in the sediment was removed (78-85%). The potential of sediment remediation with the amendment of sediment withcarbon rich materials was examined from the aspect of selecting carbon sorption agents (activated carbon, biochar and humus); estimation the optimal material doses; the long -term and short-term effects of the addition of these agents on the bioavailability of organic pollutants in order to examine the effect of aging and the toxicity of the resulting mixtures. The results of the stabilization of pollutants in the sediment show that: (1) increasing the dose of all three sorption agents leads to an increase in the immobilization efficiency and reduction of the bioavailable fraction of the selected organic compounds; (2) aging of the amended sediment during the first 90 days results in a further reduction of the biodegradable fraction of all compounds, after which the biodegradable concentration of the selected compounds remain the same in the case of activated carbon amendment, while the bioavailable fraction of the compound increases with the use of biohar and humus. Phytotoxicity tests showed that <em>Zea mays </em> accumulated significantly higher amount of selected organic pollutants from unamended sediment, comparing to <em>Cucurbita pepo </em> and <em>Lactuca sativa</em>. Toxicity of activated carbon and humus amended sediment assessed by <em>Vibrio fischeri </em> luminescence inhibition test and by measuring <em>Zea mays </em>germination and biomass yield was significantly reduced in the amended sediment samples. Accumulation of the selected organic pollutants in the <em>Zea mays</em> biomass in the unamended sediment were a significantly higher than in the humus and activated carbon amended sediment. Both sorbents show potential to be used as remediation agents for organically contaminated sediment, but activated carbon exhibited the better performance.</p>
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