Målet med den här studien var att undersöka kiselalger och dess eventuella missbildningar i tre vattendrag i södra Sverige - Höje å, Skivarpsån och M42. Kiselalger används som bioindikator för vattenkvalitet i hela Europa, men de befintliga kiselalgsindexen visar inte eventuell förekomst av miljöfarliga ämnen. Det har dock visats att en förekomst > 1 % av missbildade kiselalger indikerar påverkan av miljöfarliga ämnen, såsom pesticider och tungmetaller. Denna studie är en av få som har undersökt kiselalgers missbildningar i vattendrag som är mer eller mindre påverkade av herbicider. Sex prov från varje vattendrag analyserades - kiselalger räknades och identifierades till artnivå och missbildningar dokumenterades och kategoriserades. Vattendragen delades in efter PTI (Pesticide Toxicity Index), där Höje å hade lägst PTI och ansågs minst påverkad av herbicider. Skivarpsån och M42 hade högre PTI, och ansågs därför ha en högre herbicidpåverkan. Det fanns en signifikant skillnad i missbildningsfrekvens vattendragen emellan, den kunde dock inte kopplas till PTI. Både Höje å och M42 hade > 1 % missbildningar. Skivarpsåns missbildningsfrekvens var < 1 % trots vattendragets relativt höga PTI. Det är möjligt att missbildningsfrekvensen bättre hade reflekterat PTI om herbicidprovtagningen skett någon månad tidigare, då herbicidhalter kan variera och kiselalger har visat sig kunna spegla ett vattendrags mående upp till tre månader bakåt i tiden. En annan förklaring till en varierande missbildningsfrekvens kan vara en lika varierande artsammansättning. Vissa arter är mindre “benägna” att missbildas än andra - ett prov som domineras av sådana skulle därför kunna innehålla få missbildningar trots eventuell miljögiftspåverkan. Det krävs dock ytterligare studier för att bättre förstå kiselalgers missbildningar i förhållande till herbicider.

This work is focused on the determination of polar pesticides in surface and waste waters. In this study Mecoprop-P, MCPA, Dichlorprop-P, 2,4-D and MCPBA in differently loaded surface waters and communal waters from sewage treatment plants were analyzed. These herbicides are included in the group identified as environmental quality standards. Some of herbicides (2,4-D and MCPA) were selected because their consumption in the Czech Republic exceeds 30 tons a year. Samples were collected prom three rivers near town of Jaroměř (Elbe, Úpa and Metuje Rivers), from one river near the town of Brno (Svratka River) and from inflow and outflow of two sewage treatment plants (WWTP Jaroměř, WWTP Brno – Modřice). Particular rivers were chosen for monitoring due to the probability of occurrence of herbicides, because they flow through agriculturally cultivated areas. Solid phase extraction (SPE) was used for the isolation of target compounds and their concentration. Gas chromatography with tandem mass spectrometry (GC/MS/MS) was used for the determination of target analytes in surface and waste waters. Selected herbicides were detected in all collected samples.

<p>Ispitana je kinetika i mehanizam fotokatalitičke&nbsp;razgradnje herbicida kvinmeraka i klomazona u prisustvu&nbsp;UV/TiO₂&nbsp; Degussa P25, odnosno piklorama i&nbsp; klopiralida&nbsp;<br />primenom UV/TiO₂&nbsp; Wackherr pri različitim&nbsp;eksperimentalnim uslovima. Praćena je i kinetika&nbsp;razgradnje odabranih herbicida direktnom fotolizom uz&nbsp;primenu sunčevog, UV i vidljivog zračenja, kao i u&nbsp;odsustvu svetlosti. Pored toga, upoređena je efikasnost&nbsp;<br />UV/TiO₂&nbsp; Degussa P25, odnosno UV/TiO₂&nbsp; Wackherr sa&nbsp;vidljivim zračenjem, kao i direktnom fotolizom u&nbsp;prisustvu pomenutih izvora svetlosti.&nbsp; U cilju procene&nbsp;<br />citotoksičnosti klomazona i klopiralida, kao i sme&scaron;e&nbsp;klomazona i klopiralida i njihovih intermedijera nastalih&nbsp;tokom fotokatalitičke razgradnje ispitan je&nbsp; in vitro&nbsp; rast&nbsp;<br />ćelijskih linija&nbsp; MRC-5 i H-4-II-E.&nbsp; Nakon ispitivanja&nbsp;fotokatalitičke razgradnje odabranih herbicida u dvaput&nbsp;destilovanoj vodi, praćena je njihova razgradnja i u&nbsp;prirodnim vodama. Takođe, ispitan je uticaj dodatka&nbsp;hidrogenkarbonata i huminske kiseline na efikasnost&nbsp;razgradnje odabranih herbicida. Fotokatalitička razgradnja&nbsp;klomazona, piklorama i mekopropa je ispitivana i u&nbsp;prisustvu UV/TiO₂&nbsp; nanocevi. Aktivnost katalizatora TiO_2&nbsp;Wackherr&nbsp; i TiO₂&nbsp; nanocevi je upoređena sa TiO₂&nbsp; Degussa&nbsp;P25.</p> / <p>The kinetics and mechanism of photocatalytic degradation&nbsp;of the herbicides quinmerac and clomazone in the&nbsp;presence of UV/TiO₂&nbsp; Degussa P25, and of picloram and&nbsp;clopyralid using UV/TiO₂&nbsp; Wackherr under different&nbsp;experimental conditions were studied. The kinetics of&nbsp;degradation of selected herbicides by direct photolysis&nbsp;using sunlight, UV and visible radiation, and in the&nbsp;absence of light were followed. In addition, the&nbsp;efficiencies of UV/TiO₂&nbsp; Degussa P25 and UV/TiO_2&nbsp;Wackherr &nbsp;were compared with visible radiation and direct&nbsp;photolysis in the presence of the above mentioned light&nbsp;sources. In order to evaluate the cytotoxicity of clomazone&nbsp;<br />and clopyralid alone and in their mixture with&nbsp;intermediates formed during the photocatalytic&nbsp;degradation, in vitro growth of cell lines, MRC-5 and H-4-II-E was followed. After examining&nbsp; the photocatalytic&nbsp;degradation of selected herbicides in double distilled&nbsp;water, their decomposition in natural waters was also&nbsp;followed. Also, the influence of hydrogencarbonate and&nbsp;humic acid addition on the efficiency of degradation of&nbsp;selected herbicides was studied. Photocatalytic&nbsp;degradations of clomazone, picloram and mecoprop were&nbsp;investigated in the presence of UV/TiO_2&nbsp;nanotubes. Activities of the catalysts TiO₂&nbsp; Wackherr and TiO_2&nbsp;nanotubes were compared to TiO₂ Degussa P25.</p>

No description available.

<p>Kao &scaron;to je poznato, RS-2-(4-hlor-o-toliloksi)propionska kiselina (MCPP),&nbsp;(4-hlor-2-metilfenoksi)sirćetna kiselina (MCPA) i 3,6-dihlorpiridin-2-karboksilna kiselina &nbsp;(klopiralid) su herbicidi sa veoma &scaron;irokim spektrom dejstva, a pored toga su rastvorljivi u&nbsp;vodi, te&scaron;ko biorazgradljivi i prema literaturnim podacima su, nažalost, veoma često prisutni&nbsp;herbicidi u pijaćoj vodi. Proces heterogene fotokatalize uz primenu TiO₂i UV zračenja se&nbsp;pokazao kao veoma pogodan način za njihovo uklanjanje iz vode. Međutim, zbog velikog&nbsp;energetskog procepa od 3,2 eV (anataze-oblik), odnosno, 3,0 eV (rutil-oblik), veoma mali&nbsp;udeo bliskih UV zraka iz sunčeve svetlosti (oko 3&minus;4%) biva iskori&scaron;ćen u toku&nbsp;fotokatalitičkog procesa, &scaron;to ukazuje na to da je TiO_2&nbsp;praktično neaktivan u prisustvu&nbsp;sunčeve svetlosti. Na osnovu literaturnih podataka je zapaženo da postoji mogućnost&nbsp;fotorazgradnje pojedinih supstrata u prisustvu TiO_2&nbsp;primenom vidljive svetlosti. Na&nbsp;primeru MCPP je ispitana aktivnost TiO_2&nbsp;Degussa P25 kao fotokatalizatora u prisustvu&nbsp;vidljive svetlosti. Na osnovu refleksionih spektara je utvrđeno da MCPP adsorbovan na&nbsp;TiO_2&nbsp;Degussa P25 apsorbuje vidljivi deo spektra (&lambda; &ge;400 nm). Nastali prelazni kompleks&nbsp;je potvrđen FTIR merenjima. Efikasnost TiO2Degussa P25 primenom vidljive svetlosti je&nbsp;upoređena sa sunčevim i UV zračenjem, kao i direktnom fotolizom u prisustvu pomenutih&nbsp;izvora zračenja. Brzina fotokatalitičke razgradnje MCPP primenom vidljive svetlosti iznosi&nbsp;0,86 &mu;mol dm^&minus;3min^&minus;1, &scaron;to je oko 4 puta brže u poređenju sa direktnom fotolizom. Nadalje&nbsp;je ustanovljena optimalna masena koncentracija katalizatora od oko 8 mg cm^&minus;3, koja je&nbsp;znatno vi&scaron;a u poređenju sa primenom UV zračenja. Razlog je najverovatnije različit&nbsp;mehanizam fotorazgradnje koji se odvija primenom vidljivog i UV zračenja. Naime,&nbsp;prisustvo 2-metil-2-propanola (poznatog hvatača&nbsp;^&bull;OH-radikala) praktično ne utiče na&nbsp;brzinu fotokatalitičke razgradnje MCPP p rimenom vidljive svetlosti, &scaron;to ukazuje da se&nbsp;mehanizam razgradnje MCPP primenom &nbsp;vidljive svetlosti ne odvija posredstvom&nbsp;^&bull;OH-radikala, za razliku od onog uz primenu UV zračenja.</p><p>S obzirom da se katalizator TiO_2&nbsp;Degussa P25 uz primenu vidljive svetlosti nije&nbsp;<br />pokazao kao naročito efikasan kada je u pitanju razgradnja sva tri herbicida i imajući u&nbsp;vidu da se u poslednje vreme iz razloga praktične primene sve vi&scaron;e pribegava procesu dopovanja TiO_2&nbsp;različitim tipovima metala (alkalnih, zemnoalkalnih, prelaznih i dr.) i nemetala (halogenida, halkogenida i dr.), u okviru ove doktorske disertacije je ispitana aktivnost N-TiO₂(sintetisanih mokrim i suvim putem) i TiO_2&nbsp;(rutil) dopovanog sa različitim količinama Fe³⁺-jona (0,13&minus;1,48 at.%) pri razgradnji herbicida MCPP i MCPA primenom vidljive svetlosti. Pored toga je ispitana efikasnost TiO_2&nbsp;(anataze) takođe dopovanog sa različitim količinama Fe³⁺-jona (0,71&minus;1,80 at.%) na primeru MCPP.&nbsp;</p><p>Poredeći N-TiO_2&nbsp;(sintetisan mokrim putem) i N-TiO_2&nbsp;(sintetisani suvim putem), primećeno&nbsp;je da je u drugom slučaju efikasnost katalizatora veća oko 2 puta. Isto tako je zapažena u&nbsp;slučaju MCPP ne&scaron;to veća fotokatalitička aktivnost N-TiO_2&nbsp;(sintetisani suvim putem) u&nbsp;poređenju sa TiO_2&nbsp;(anataze). Kada je u pitanju MCPA aktivnost sva tri katalizatora je&nbsp;veoma slična. Pored toga je zapažena veća efikasnost N-TiO_2&nbsp;(sintetisan mokrim putem) u&nbsp;poređenju sa TiO_2&nbsp;Degussa P25 (oko 1,5 puta) i oko 5 puta u odnosu na direktnu fotolizu,&nbsp;dok su N-TiO_2&nbsp;(sintetisani suvim putem) oko 3 puta efikasniji u poređenju sa TiO_2&nbsp;Degussa P25 i oko 10 puta u &nbsp;poređenju sa direktnom fotolizom. Brzina solarne razgradnje&nbsp;je preko 100 puta manja nego primenom vidljivog i UV zračenja, &scaron;to je posledica različitih&nbsp;intenziteta pomenutih izvora ozračivanja i različitih uslova pri kojima je vr&scaron;ena razgradnja. &nbsp;Ustanovljena je optimalna masena koncentracija N-TiO_2&nbsp;(sintetisan mokrim putem) od&nbsp;4 mg cm^&minus;3.</p><p>Prilikom razgradnje MCPP i MCPA je nađeno da je brzina veća kada se kao&nbsp;katalizator &nbsp;koristi TiO_2&nbsp;(rutil) u poređenju sa Fe-TiO_2&nbsp;i da sa povećanjem količine Fe³⁺-jona fotokatalitička aktivnost uglavnom opada. Kada je kao fotokatalizator kori&scaron;ćen TiO_{2 &nbsp;}<br />(anataze) dopovan različitim količinama Fe³⁺-jona (od 0,71 do 1,80 at.%), razgradnja&nbsp;<br />MCPP je u svim slučajevima znatno sporija u odnosu na TiO_2&nbsp;(anataze).</p><p>S obzirom da su prema literaturnim podacima kinetika i mehanizam fotokatalitičke&nbsp;<br />razgradnje klopiralida nepoznati, ispitana je njegova stabilnost pri različitim&nbsp;eksperimentalnim uslovima. Tokom ispitivanja uticaja pH kako u prisustvu, tako i u&nbsp;odsustvu dnevne svetlosti u intervalu pH od 1,0&minus;9,0, nađeno je da ni u jednom slučaju ne&nbsp;dolazi do razgradnje supstrata u periodu od sedam meseci koliko je proces praćen. Takođe&nbsp;je ispitana kinetika fotokatalitičke razgradnje klopiralida primenom UV i vidljivog&nbsp;zračenja u prisustvu TiO_2&nbsp;Degussa P25, kao i direktna fotoliza primenom oba izvora&nbsp;zračenja. Nađeno je da je brzina fotokatalitičke razgradnje primenom UV zračenja veća&nbsp;oko 5 puta u odnosu na direktnu fotolizu. Za praćenje toka fotokatalitičke razgradnje&nbsp;klopiralida je izabrana pH-vrednost od 3,2. Nadalje je zapaženo da se u ispitivanom opsegu početnih koncentracija supstrata (0,5&ndash;3,0 mmol dm^&minus;3) kinetika fotokatalitičke razgradnje klopiralida može opisati pseudo-prvim redom. Pri ispitivanju uticaja masene koncentracije katalizatora (0,5&ndash;8 mg cm^&minus;3) na brzinu razgradnje klopiralida, ustanovljena je optimalna masena koncentracija primenjenog fotokatalizatora od oko 4 mg cm^&minus;3. Izračunata ukupna &nbsp;prividna energija aktivacije iznosi 7,74 kJ mol^&minus;1. Pored toga, prisustvo kiseonika ubrzava reakciju 2 puta, dok dodatak elektron-akceptora kao &scaron;to su (NH₄)₂S₂O₈, H₂O_2&nbsp;i KBrO_3&nbsp;pokazuje značajan i različit efekat na kinetiku fotokatalitičke razgradnje klopiralida. Pri ispitivanju uticaja etanola, kao hvatača slobodnih radikala, nađeno je da se heterogena fotokataliza odvija uglavnom preko ^&bull;OH-radikala.</p><p>Na osnovu LC&ndash;MS/MS (ESI+) merenja ustanovljeno je prisustvo nekoliko&nbsp;intermedijera: 3,6-dihlor-piridin-2-ol, 3,6-dihlor hidroksipiridin-2-karboksilna kiselina i&nbsp;3,3&#39;,6,6&#39;-tetrahlor-2,4&#39;-bipiridin-2&#39;-karboksilna kiselina. Na osnovu identifikovanih&nbsp;intermedijera, kao i kinetičkih rezultata, predložen je mogućput mehanizma fotokatalitičke&nbsp;razgradnje klopiralida.</p><p>Prilikom ispitivanja uticaja strukture molekula na brzinu razgradnje, konstatovano&nbsp;<br />je da u slučaju klopiralida praktično ne dolazi do fotokatalitičke razgradnje u prisustvu&nbsp;TiO_2&nbsp;(anataze) i N-TiO_2&nbsp;(sintetisani suvim putem) uz primenu vidljive svetlosti, kao i u&nbsp;slučaju TiO_2&nbsp;Degussa P25. Pored toga, primenom TiO_2&nbsp;(rutil) i Fe-TiO_2&nbsp;kao&nbsp;fotokatalizatora, sa povećanjem količine Fe³⁺-jona od 0,13 do 1,27 at.% raste brzina&nbsp;razgradnje klopiralida, ukazujući da strukturne osobine supstrata utiču na brzinu njihove&nbsp;razgradnje.</p> / <p>It is well known that RS-2-(4-chloro-o-tolyloxy)propionic acid (MCPP), (4-chloro-2- methyl-phenoxy)acetic acid (MCPA) and 3,6-dichloropyridine-2-carboxylic &nbsp;acid&nbsp;(clopyralid) are herbicides of wide activity spectrum. They are soluble in water, hardly&nbsp;biodegradable and, unfortunately, often present in drinking water.</p><p>Heterogeneous photocatalysis by application of TiO_2&nbsp;and UV radiation proved to&nbsp;be very suitable for their removal from water. However, due toits large energy gap, i.e.&nbsp;3.2 &nbsp;eV (anatase-form) and 3.0 eV (rutile-form), a very small fraction of sunlight in the near&nbsp;UV range (about 3&ndash;4%) is used during photocatalytic process, which is an indication of&nbsp;TiO_2&nbsp;inactivity in the presence of this light source. Some literature data report on the&nbsp;possibility of photodegradation of certain substrates by visible light in the presence of&nbsp;TiO₂. MCPP served as substrate for testing TiO_2&nbsp;Degussa P25 &nbsp;photocatalytic activity in the&nbsp;presence of visible light. On the basis of reflection spectra it was established that MCPP&nbsp;adsorbed on TiO_2&nbsp;Degussa P25 was absorbing visible spectrum radiation (&lambda; &ge;400 nm).&nbsp;The existence of thus formed &nbsp;charge-transfer complex was confirmed with FTIR analysis.&nbsp;The efficiency of &nbsp;TiO_2&nbsp;Degussa P25 with application of visible light was compared to&nbsp;sunlight and UV radiation, as well to directphotolysis in the presence of these light&nbsp;sources. The rate of MCPP photocatalytic degradation by means of visible light is&nbsp;0.86 &mu;mol dm^{&minus;3&nbsp;}min^&minus;1, which is about 4 times faster than direct photolysis. In addition, the&nbsp;optimal &nbsp;catalyst concentration of about 8 mg cm^&minus;3, much higher than using UV radiation,&nbsp;<br />was established. The reason is, probably, a different mechanism of &nbsp;hotodegradation &nbsp;in the&nbsp;presence of visible and UV irradiation. Namely, the presence of 2-methyl-2-propanol&nbsp;(well-known&nbsp;^&bull;OH radical scavenger) has practicallyno effect on the rate of &nbsp;MCPP&nbsp;photocatalytic degradation using visible light, which points that this degradation&nbsp;mechanism does not involve&nbsp;^&bull;OH radicals, in contrast to that established &nbsp;for UV radiation.</p><p>Since the catalyst TiO_2&nbsp;Degussa P25 with application of visible light was not very&nbsp;<br />efficient in degradation of all three herbicidesand in view that nowadays is very &nbsp;popular&nbsp;doping process of TiO₂ with different types of metals (alkali, alkaline-earth, transition, etc.)&nbsp;and non-metals (halogen, chalcogen, etc.), in the scope of this Ph.D. &nbsp;thesis activities of N-TiO_2&nbsp;(synthesized by wet and dry procedure) and TiO_2&nbsp;(rutile) doped with various amounts&nbsp;of Fe^3+&nbsp;(0.13&ndash;1.48 at.%) in degradation processes of &nbsp;herbicides MCPP and MCPA using&nbsp;visible light were studied. In addition, the efficiency of TiO_2&nbsp;(anatase) doped with various&nbsp;amounts of Fe^3+&nbsp;(0.71&ndash;1.80 at.%) was also tested for MCPP degradation. When comparing&nbsp;N-TiO_2&nbsp;(synthesized by wet procedure) and N-TiO₂ (dry procedure), it was observed that&nbsp;in the latter case the catalyst efficiency was about two times higher. In this case for MCPP&nbsp;was also observed somewhat higher photocatalytic activity of N-TiO₂ (synthesized by dry&nbsp;procedure) in comparison with TiO₂. When activities of all three catalysts towards MCPA&nbsp;are compared, the results are very alike. In addition, higher efficiency of N-TiO_{2 &nbsp;}(wet&nbsp;procedure) comparing to TiO_2&nbsp;Degussa P25 (about 1.5 times) and about 5 times in&nbsp;comparison to direct photolysis were recorded, while N-TiO₂ (dry procedure) was about 3&nbsp;times more efficient than TiO_2&nbsp;Degussa P25 and about 10 times in comparison with direct&nbsp;photolysis. The rate of solar degradation is about 100 times lower than by application of&nbsp;UV and visible radiation, as a consequence of various intensities of the mentioned light&nbsp;sources and different conditions of photodegradation. An optimal concentration of N-TiO₂&nbsp;(wet procedure) of 4 mg cm^&minus;3<br />&nbsp;was established.</p><p>During degradation of MCPP and MCPA it was observed that the rate is higher if&nbsp;TiO₂(rutile) was applied comparing to Fe-TiO_2&nbsp;and with increasing amount of Fe^3+&nbsp;photocatalytic activity mostly decreases. When TiO₂ (anatase) doped with various amounts&nbsp;of Fe^3+&nbsp;(0.71 to 1.80 at.%) was applied for MCPP degradation, the process was much&nbsp;slower than with undoped catalyst.</p><p>Since we have not found relevant literature data on kinetics and mechanism of&nbsp;photocatalytic degradation of clopyralid, its stability in different experimental conditions&nbsp;was tested. In investigating of influences of pH (1.0&ndash;9.0) both in presence and in absence&nbsp;of daylight, in no cases decomposition was observed during seven months experiments.&nbsp;Also, the kinetics of photocatalytic degradation of clopyralid using UV and visible&nbsp;irradiation in the presence of TiO_2&nbsp;Degussa P25 and in direct photolysis by application of&nbsp;both irradiation sources was studied. It was found that the &nbsp;rate of photocatalytic&nbsp;decomposition using UV radiation was 5 times higher comparing to direct photolysis. For&nbsp;clopyralid photocatalytic monitoring a pH value of &nbsp;3.2 was chosen. In addition, in the investigated concentration range (0.5&ndash;3.0 mmol &nbsp;dm^&minus;3) the photocatalytic degradation kinetics of clopyralid in the first stage of the reaction follows approximately a pseudo-first kinetic order. In investigation of influence of catalyst concentration (0.5&ndash;8 mg cm^&minus;3) on the rate of clopyralid degradation the highest reaction rate was observed at 4 mg cm^{&minus;3&nbsp;}of catalyst concentration The apparent activation energy of the reaction being 7.74 kJ mol^&minus;1. The absence of molecular oxygen resulted in a significant decrease (about 2 times) in the rate of clopyralid photodegradation. The effect of the presence of (NH₄)₂S₂O₈, H₂O_2&nbsp;and KBrO₃, acting as electron acceptors along with molecular oxygen affects clopyralid photocatalytic degradation considerably and indifferent ways. By studying the effect of ethanol as a hydroxyl radical scavenger it was shown that the heterogeneous catalysis takes place mainly via ^&bull;OH radicals.</p><p>LC&minus;MS/MS (ESI+) monitoring of the process showed that several pyridine-containing intermediates are formed: 3,6-dichloropyridin-2-ol, 3,6-dichloro&nbsp;hydroxypyridine-2-carboxylic acid and 3,3&#39;,6,6&#39;-tetrachloro-2,4&#39;-bipyridine-2-carboxylic&nbsp;acid. Based on the identified intermediates and overall kinetic results, a probable&nbsp;photocatalytic degradation mechanism was proposed.&nbsp;</p><p>Finally, in the case of clopyralid it was established that practically no degradation&nbsp;<br />occurs in the presence of TiO_2&nbsp;(anatase) and N-TiO₂ (dry procedure) with visible light &nbsp;and&nbsp;also with TiO_2&nbsp;Degussa P25. Besides of that, by using TiO_2&nbsp;(rutile) and Fe-TiO_2&nbsp;as&nbsp;photocatalysts it was noted that increasing the concentration of Fe^3+&nbsp;from 0.13 to 1.27 at.%&nbsp;comes to increasing photodegradation rate of clopyralid. Results indicate that differences&nbsp;in molecular structure of chosen compound, influence obtained photocatalytic activity to a&nbsp;great extent.</p>

A variety of conservation trends have gained and lost favor throughout the years in agriculture, with U.S. Farm Bills often influencing what conservation practices are implemented by farming communities throughout the U.S. This dissertation focuses on the unintended consequences of conservation management practices in the Fifteenmile Watershed of Wasco County, Oregon. Specifically, I seek to address how farmer enrollment in various conservation techniques, loosely defined as no-till agriculture, has affected soil and water quality through the increased use of herbicide, and subsequently rendered ecological and human health vulnerable. Using a critical physical geography framework, I address both the biophysical factors and social structures that have co-produced changes in soil and water quality in the study area of this research through intensive physical field data collection, spatial analysis, social surveys, and interviews. I also demonstrate how three neoliberal sets of processes: market-friendly reregulation; state rollback and deregulation; and the creation of self-sufficient individuals and communities, have transformed the human socio-environmental relationship to agriculture. These processes have had significant effects on the policies governing how soil and water quality are managed on both a state and national level, and have created a dependence on enrollment in conservation practices that may ultimately prove counterproductive for long term goals of environmental protection and sustainability.

A água é um recurso natural que, apesar de abundante, tem sofrido grande restrição em sua disponibilidade por conta da atividade humana, principalmente a agricultura. A garantia de conformidade da água que é distribuída à população quanto aos níveis tidos como seguros para a presença de contaminantes é, portanto, uma questão de saúde pública e que tem atraído grande atenção. De modo a detectar substâncias potencialmente nocivas, complexos procedimentos de química analítica são utilizados para a verificação e emissão de laudos de conformidade, utilizados para a tomada de decisão em relação à sua potabilidade. Neste cenário há demanda para métodos auxiliares para guiar a amostragem e realizar a triagem de amostras. O glifosato é o herbicida sistêmico não seletivo mais utilizado no mundo. Tal substância tem recebido crescente atenção, principalmente devido à sua ampla utilização e controvérsia em relação ao seu efeito potencialmente cancerígeno. Neste trabalho é apresentado um método para a detecção de glifosato diretamente em meio aquoso a partir da interrogação espectroscópica assistida por nanopartículas de prata. Com uso do espalhamento Raman, a região de assinatura espectral de moléculas em solução aquosa é acessível na região visível do espectro eletromagnético. Entretanto, o limite de deteção para este tipo de interrogação é prejudicado pela baixa intensidade do sinal ótico gerado. A intensificação do espalhamento Raman por um corpo metálico nanoestruturado é uma técnica que permite a detecção de traços de substâncias por meio de seu espectro vibracional. Nanopartículas esféricas de prata, com tamanhos de 5 a 20 nm, foram produzidas a partir da técnica de Ablação a Laser Pulsado em Líquidos resultando em uma solução coloidal estabilizada por íons de citrato, usado como surfactante. Um aparato experimental, composto por dois espectrofotômetros a fibra ótica e bombeamento por fontes de radiação laser e banda larga, foi implementado para interrogação das amostras de água com potencial presença de glifosato. O espectro vibracional foi obtido pela medição do espalhamento Raman intensificado em superfície (SERS) do conjunto de aglomerados de nanopartículas de prata formado pela agregação mediada pelo analito. Por meio do espectro de extinção UV-Vis, o estado de agregação das nanopartículas em solução coloidal foi medido. A partir dessa agregação, foi possível medir uma banda de espalhamento Raman intensificado dependente da concentração do analito. Um mecanismo baseado na interação entre o analito e o substrato foi proposto. A a partir dos resultados, realizou-se o ajuste na produção das nanopartículas, bem como sua interação com as amostras, permitindo a determinação do limite de detecção de 6,0 e 7,5 μM (1,0 e 1,3 ppm) para as duas técnicas de interrogação, UV-Vis e Raman, respectivamente. Um sistema de reconhecimento de padrões baseado no método da Análise de Discriminantes pelos Mínimos Quadrados Parciais (PLS-DA) foi implementado para a classificação de amostras. O sistema emprega a fusão em baixo nível dos dados espectroscópicos, UV-Vis e Raman, num único espaço de características. O sistema foi treinado e validado a partir de amostras de água deionizada e testado com amostras de água in natura com adição de glifosato. Considerando um limite de decisão de 10 μM, foi obtido um valor de acurácia de classificação de 0,85. / Water is a natural resource that, although abundant, has been under great limitation in its availability due to human activity, mainly agriculture. Ensuring compliance of the water that is distributed to the population on levels considered safe for the presence of contaminants is therefore a public health issue and has attracted great attention. In order to detect potentially harmful substances, complex analytical chemistry procedures are used to verify and issue conformity reports used for decision making regarding its potability. In this scenario there is a demand for auxiliary methods to guide sampling and to perform sample screening. Glyphosate is the most widely used non-selective systemic herbicide in the world. Such a substance has received increasing attention, mainly due to its wide use and controversy regarding its potentially carcinogenic effect. This work presents a method for the detection of glyphosate directly in aqueous medium from the spectroscopic interrogation assisted by silver nanoparticles. With the use of Raman scattering, the region of spectral signature of molecules in aqueous solution is accessible in the visible region of the electromagnetic spectrum. However, the detection limit for this type of interrogation is impaired by the low intensity of the optical signal generated. The enhancing of Raman scattering by a nanostructured metallic body is a technique that allows the detection of traces of substances by means of their vibrational spectrum. Silver spherical nanoparticles, ranging from 5 to 20 nm in diameter, were produced by Pulsed Laser Ablation in Liquid (PLAL) technique, resulting in a colloidal solution stabilized by citrate ions, used as a surfactant. An experimental apparatus composed of two optical fiber spectrophotometers, and pumping by laser and wideband radiation sources, was implemented to interrogate water samples with the potential presence of glyphosate. The vibrational spectrum was obtained by measuring the surface enhanced Raman scattering (SERS) of the silver nanoparticle clusters, formed by the analyte-mediated aggregation. By means of the UV-Vis extinction spectrum, the state of aggregation of the nanoparticles in colloidal solution was measured. From this aggregation, it was possible to measure one of the analyte concentration dependent enhanced Raman scattering band. A mechanism based on the interaction between the analyte and the substrate has been proposed. From the results, the tuning of the nanoparticles production, as well as their interaction with the samples was carried out. The limit of detection (LOD) of 6.0 and 7.5 μM (1.0 and 1.3 ppm) for the two interrogation techniques, UV-Vis and Raman, respectively, was achieved. A pattern recognition system based on the Partial Least Squares Discriminant Analysis (PLS-DA) method has been implemented for the classification of samples. The system employs the low level fusion of the spectroscopic data, UV-Vis and Raman, in a unique feature space. The system was trained and validated with deionized water samples and tested with fresh water samples with addition of glyphosate. Considering a decision limit of 10 μM, a classification accuracy of 0.85 was obtained.

Presented Diploma Thesis is focused on electroanalytical determination of the herbicide Aclonifen, which belongs to a group of herbicides derived from diphenylether. These herbicides are used due to their effects - inhibition of protoporfyrinogen oxidase synthesis and also inhibition of biosynthesis of carotenoids. Due to its widespread use in agricultural, toxical effects on humans and because of its negative impacts particularly on aquatic ecosystems there is a need for methods capable of determining the presence of Aclonifen in the environment to monitor its ecological impacts. Optimal conditions for the determination of Aclonifen have been investigated in BR buffer - methanolic solution and in BR buffer. Electrochemical behavior of the substance has been studied using direct current voltammetry (DCV), differential pulse voltammetry (DPP) and adsorptive stripping voltammetry (AdSV) on the hanging mercury drop electrode (HMDE) and by using TAST polarography and differential pulse polarography (DPP) on the dropping mercury electrode (DME). UV/VIS spectrophotometric detection was used for comparison to electrochemical detection. Used wavelengths were 308 nm and 388 nm. For electrochemical determination of Aclonifen the above mentioned techniques were used and following results were obtained: DCV...

Arable plant species diversity has been on a decline, with many species dependent on arable land becoming threatened. At the same time, attempts at defining the drivers of arable plant diversity have proven difficult and results are often contradictory. Much of the available data come from surveys that are small-scale and with great variability in methodology, leading to difficulties comparing them. In this study, I have used survey data from Gotland to examine how arable plant diversity is influenced by management, field size, soil texture and standing crop. I found a negative trend of diversity with increasing field size, and a suggested effect of management and soil texture on the presence of red listed arable plants. This study also evaluates the use of small datasets when examining plant diversity, and the limitations associated with it. It shows that while a small dataset cannot be analysed to the extent a more comprehensive one can, it is possible to identify trends and patterns with it, which may inform further studies.

Since 1750, human emissions of greenhouse gases have created a temperature increase, affecting the whole world. Diatoms, single-celled microscopic algae that lives in waters all over the world, have different environmental preferences such as the water depth at which the thrive, salinity, nutrients, pH-values and more. Diatoms also responds quickly to changing circumstances, which makes the suitable as environmental indicators. The purpose of the study is to investigate how the abundance and composition of diatoms has changed during the last 200 years in lake Ensjön, located just south of Norrköping, and to relate those changes both to climate change and known events and environmental factors in the area.  The survey is conducted by subsampling sediment cores from which each diatom sample was prepared in accordance with the scheme of Battarbee (1984). The diatoms in the samples were counted under a microscope and the results were analyzed and related to the Cyclotella-Aulacoseira-Fragilaria-theory (CAF) and documented historical events in the local environment. The result of the analysis shows that the composition and abundance of diatoms has changed during the last 200 years, and that this change is due to both climate change (temperature and precipitation increase) and the land-use history of Ensjön. The cahnges in composition of Aulacoseira spp. and Cyclotella spp., where Aulacoseira spp. is expected to decrease, and Cyclotella spp. is expected to increase with a rising temperature, match the CAF-theory for the most part. The change in composition also coincides with several documented environmental factors in the area, especially the change in use of fertilizers and herbicides in agriculture. / Människans utsläpp av växthusgaser har sedan år 1750 skapat en temperaturökning som går allt snabbare, och påverkar hela världen. Kiselalger, encelliga mikroskopiska alger som lever i vatten över hela världen, har olika miljöpreferenser såsom bland annat på vilket vattendjup de trivs, optimal halt av salt, näringsvärden, pH-värden, samt reagerar snabbt på förändrade omständigheter, vilket gör dem lämpliga som miljöindikatorer. Syftet med studien är att studera förändringar i kiselalgernas sammansättning under de senaste 200 åren i den lilla sjön Ensjön belägen något söder om Norrköping och att relatera dessa förändringar till dokumenterade händelser och miljöfaktorer i sjöns avrinningsområde samt till de pågående klimatförändringarna.  Undersökningen är utförd genom provtagning av sedimentkärnor från vilka prover preparerades enligt Battarbees (1984) flödesschema. Proverna av kiselalger räknades under mikroskop och sammansättningen analyserades utifrån teorin Cyclotella-Aulacoseira-Fragilaria (CAF) och kända historiska händelser i närmiljön. Analysresultatet visade att kiselalgssammansättningen har förändrats under de senaste 200 åren, och att denna förändring sannolikt kan kopplas både till klimatförändringar (en ökad temperatur) och Ensjöns markanvändningshistoria. Förändringen hos Aulacoseira spp. och Cyclotella spp. följer till stor del CAF-teorin om att det första släktet skulle minska och det andra skulle öka vid en temperaturökning. Vid flera tillfällen sammanfaller förändringar i kiselalgssammansättningen med kända miljöfaktorer i närmiljön, främst i samband med utvecklingen i användningen av mineralgödsel och växtskyddsmedel.