The diploma thesis is focused on the determination of tetracyclines, sulfonamides and fluoroquinolones from soil. Antibiotics such as tetracycline, chlortetracycline, oxytetracycline. ciprofloxacin, trimethoprim, sulfamethaxazole and sulfadiazin were selected due to frequent use in veterinary medicine. Due to the fact that the soil is a complex matrix and contains many components that can interfere with the detection signal of analytes, it was necessary to use the MAX column in the SPE method, which removes fulvic aned humic acid from analytes and the HLB column Final analysis of the analytes was performed by liquid chromatography with mass detesction (LC-MS). The method was also used for real soil samples, which were delivered from ÚKZUS.

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A cation exchange method (Chelex 100) that distinguishes weakly bound and strongly bound copper was investigated for its ability to measure bioavailable copper in estuarine waters. Copper bound to the Chelex 100 resin was operationally defined as bioavailable copper. Varying initial copper concentration from 195 to 495 ug/L at a constant 12.5 mg/L natural organic matter (NOM) did not affect percent bioavailability. There were also no noticeable effects when varying total Cu concentration in the presence of 0, 12, and 24 mg/L NOM. An increase in pH from 4 to 8.5 and NOM from 0 mg/L to 12.5 mg/L reduced percent bioavailability. Using the Chelex 100 resin to measure bioavailable copper, about 20 to 40% of the total copper was bioavailable in the absence of NOM, while about 15 to 20% was bioavailable when either 12 or 24 mg/L NOM was present. Acute toxicity bioassays were performed with mysid shrimp (Americamysis bahia) to evaluate the toxic effects of copper in the presence of Suwannee River Fulvic Acid, which served as a source of NOM. Static or static renewal tests, based on EPA method OPPTS 850.1035 with a minimum of 10 mysid shrimp per test condition, were used to determine the LC50 and EC50 of copper and the effects of NOM. Test solutions consisted of artificial synthetic seawater at 20 parts per thousand containing concentrations of 0, 100, 200, 400, 800 ug/L copper with either 0, 12, 24 mg/L NOM. Forty-eight hour acute toxicity tests were performed on larval (2 to 3 day) mysid shrimp that were fed Artemia (brine shrimp); mortality and immobilization were the endpoints. The 48 hour LC50 was 200 ug/L dissolved Cu and 94 ug/L bioavailable Cu without NOM, 340 ug/L dissolved Cu and 98 ug/L bioavailable Cu when 12 mg/L NOM was present, and 495 ug/L dissolved Cu and 105 ug/L bioavailable Cu at 24 mg/L NOM. The consistency of the LC50 measurement using bioavailable Cu suggest that the Chelex 100 resin is a useful technique for toxicity analysis in saline water. / Master of Science

Chapter 2: Germination and Growth of Radish (Raphanus sativus) and Lettuce (Lactuca sativus) Exposed to Arsenite and Arsenate in Hydroponic Growth Solution Little information is available on the survival, uptake, and dry mass production of vegetable seedlings and maturing plants in arsenic enriched environments. Such information is however very important to many vegetable growers in areas of subsistent agricultural like Bangladesh or home-gardeners in closer proximity of As sources such as metal smelters. Accordingly we conducted research investigating (i) the germination and radical formation of radish and lettuce seeds at varying As (V) and As (III) concentrations and (ii) radish and lettuce plants in solution culture. Seed germination studies demonstrated that 0.1mM and 0.025mM are toxic threshold levels of As (III and V) for radishes and lettuce, respectively, while As (V) is more toxic to radish seeds than As (III). Arsenic (III and V) impacted both germination and radical development in radish seeds. For lettuce we observed that As had no impact on germination but reduced radical length significantly (p < 0.01). At most equimolar concentrations, As (III) was more toxic than As (V) in lettuce seeds (0.025 - 0.10mM As), a result contrary to those obtained in radish seeds (0.05 - 0.5mM As). The hydroponic growth studies showed that losses and increases in dry weight are a function of absorbed As and are dependent on the source of As: As (V) or As (III). Moreover, the effect of absorbed As (V) or As (III) on dry weight reductions and increases differed between root and shoot portions of the plants and are crop dependent. Tissue-As (originally solution As (V)) was more toxic at the radish root level and tissue-As (originally solution As (III)) was more toxic at the radish shoot level. Conversely for lettuce, As (III) caused reductions in dry weight, while As (V) had a stimulating effect on biomass production. Lower As (V) concentrations in plant tissue throughout the lettuce study and at low As (V) concentrations (0.02mM) in the radish study may be explained by the molar ratio of P:As of approximately 5. From a food nutrition safety standpoint, studies need to concentrate on sub-lethal levels in order to ensure the proper formation of the harvestable portion of the plant. Chapter 3: Adsorption of Arsenate (V) and Arsenite (III) on Goethite in the Presence and Absence of Soluble Organic Carbon The environmental fate of arsenic is of utmost importance as the U.S. EPA has recently proposed to tighten the arsenic drinking water standard from 50 ppb to 5 ppb. In natural systems the presence of dissolved organic carbon (DOC) may compete with As for adsorption to mineral surfaces, hence increasing its potential bioavailability. Accordingly, the adsorption of arsenate As (V) and As (III) on goethite (α-FeOOH) was investigated in the presence of either a peat humic acid (Hap), a Suwannee River Fulvic Acid (FA) (IHSS) or citric acid (CA). Adsorption edges and kinetic experiments were used to examine the effects of equimolar concentrations of organic adsorbates on arsenic adsorption. Adsorption envelopes were conducted over a pH range of 11 to 3, while the kinetic studies were conducted at pH 6.5 for As (V) and pH 5.0 for As (III). Arsenate adsorption was inhibited in the order of Hap > FA > CA while arsenite adsorption was inhibited in the order of CA > FA > Hap. Humic acid reduces As V adsorption starting at pH 9, with a maximum reduction at pH 6.5. Fulvic acid slightly inhibited As (V) adsorption starting at pH 5, and this inhibition increased with a decrease in pH. No effect was observed in the presence of CA. Arsenite adsorption is inhibited by HA starting a pH 7 and increases with a decrease in pH, while FA and CA reduce As (III) adsorption beginning at pH 8, with a continuous reduction as the pH decreases. The differential extent of As V adsorption in the presence of the organic acids suggests that the distribution and the respective densities of the abundant functional groups (phenol/ catechol OH or COO⁻) are significant in the adsorption of As (V). Furthermore, larger organic acids may hydrophobically partition to surfaces via a more favorable entropy driven reaction mechanism which may influence As (V) diffusion and its subsequent adsorption to surfaces. The decrease in As (III) adsorption is caused by its reduced affinity for the surface at pH values lower than 9, and the simultaneous increase in surface activity by the organic substances' via their COO⁻ functional groups. The results of these experiments suggests that dissolved organic carbon substances are capable of increasing the bioavailability of As in soil and water systems in which the dominant solid phase is a crystalline iron oxide. Chapter 4: Adsorption of Arsenate and Arsenite on Ferrihydrite in the Presence and Absence of Dissolved Organic Carbon (DOC) The adsorption of As (V) and As (III) on synthetic 2-line ferrihydrite in the presence and absence of a peat humic acid (Hap), Suwannee River Fulvic Acid (FA) or citric acid (CA) was investigated. Previous work with goethite has demonstrated the ability of DOC materials to reduce As (V) and As (III) adsorption. In this study, a batch technique was used to examine the adsorption of arsenic (III and V) and DOCs on ferrihydrite in the pH range from 3 to 11. The results obtained demonstrated that As (V) adsorption on ferrihydrite was reduced only in the presence of CA. Arsenate reduced the adsorption of all organic acids except Hap. Both FA and CA reduced As (III) adsorption on ferrihydrite, while Hap had no effect. Fulvic and citric acid adsorption on ferrihydrite was reduced in the presence of As (III), however, adsorption increases of FA and CA were observed at lower pH, which is consistent with a decrease in As(III) adsorption. The peat humic acid had no effect on As (III) adsorption, and we believe that the adsorption process of Hap and As (III and V) on ferrihydrite are independent of each other. The observed differences between this study and the study on goethite are believed to be an intricate function of ferrihydrite's surface characteristics, which affects the mechanisms of surface adsorption and hence the affinity of organic acids such as Hap, FA, and CA for the ferrihydrite surface. As such, the adsorption of DOCs to ferrihydrite are assumed to be energetically less favorable and to occur with a fewer number of ligands, resulting in lower surface coverage of weaker bond strength. Additional factors for the observed differences are discussed. This work demonstrates the importance of the solid phase in adsorption processes and functional group composition, as noticeable differences are observed in comparison to a crystalline Fe-oxide solid phase. / Master of Science

Water stress is the most critical environmental factor limiting crop production in the US Piedmont. The presence of humic substances in composted organic amendments may increase crop tolerance to water stress through their hormone-like effects on plant metabolism. The objectives of this study were to calculate N mineralization rates of composted and non-composted organic materials used in this long-term field study, and to determine differences in soil physiochemical properties, corn and soybean leaf physical and biochemical properties yield and seed quality between organically amended and inorganically fertilized treatments. Nitrogen mineralization rates were greatest in the poultry litter (21%) and Panorama yard waste compost (4.5%) amended plots. Nitrogen uptake (120 mg/pot, 133 mg/pot, respectively) in these treatments were greater than that in the control (0N) (91.3 mg/pot) treatment. Wolf Creek biosolids compost and Huck's Hen Blend yard waste compost induced N immobilization (-5.0% and 0.18%, respectively), and had N uptake values similar to the control (92.6 mg/pot and 95.7 mg/pot). Rivanna biosolids compost immobilized N (-14.8%) but N uptake (136 mg/pot) was greater than that in the control due to the relatively high inorganic N content in the amendment. The total N concentration and C:N values were less reliable variables in predicting N mineralization when a significant portion of the total N was in the inorganic form. The annual application of poultry litter, Rivanna biosolids compost, and Panorama yard waste compost at 100% agronomic nitrogen and 30 % agronomic nitrogen rates in the field study improved soil fertility and increased total organic and humified carbon contents relative to the inorganically fertilized and control treatments. The amended treatments had slightly greater plant available water contents (average 10.0 cm/15 cm) than the control (8.38 cm/15 cm). Leaf water potential measurements revealed that neither crop experienced water stress during the sampling season. Treatment differences in leaf antioxidant activity were only observed in corn. All corn plants that were fertilized with amendments supplying the crop's nitrogen needs, regardless of the source, had greater leaf nitrogen (+29%), chlorophyll (+33%), and protein contents (+37%), lower superoxide dismutase (-29%) and ascorbate peroxidase (-17%) activities, and lower malondialdehyde (-33%) contents relative to the control and low nitrogen treatments. There were no observed differences in catalase activity, which was likely due to the evolutionary advantage of C4 metabolism. Yield was strongly related to midseason leaf nitrogen contents (R2=0.87, p<0.0001) and not soil humified carbon (R2=0.02, p=0.0543). There were no observed treatment differences in soybean leaf physiology and metabolism. Differences, however, were observed over time. As the leaves senesced, leaf chlorophyll, protein, superoxide dismutase and catalase activities decreased, and the malondialdehyde content increased. Ascorbate peroxidase activity slightly increased with time. Catalase activity in soybean was primarily driven by the oxidation of glycolate, a product of photorespiration, and not the formation of reactive oxygen species in the chloroplasts. The organically amended treatments had higher yields (9-21% increase), greater protein contents (4-9% increase), and seed weights (5-14% increase) relative to the fertilizer and control treatments. It was concluded that differences in soybean yield and seed quality were due to non-nutritive benefits of the organic amendments and not available water or plant nutrition. / Master of Science

An investigation was conducted focusing on how NOM affects coagulation in a United States south eastern coastal surface water. Current water treatment practice at Savannah Water I and D was investigated to determine the efficacy of NOM removal using existing coagulation methods. A robust assessment of alum and ferric sulfate for use as coagulants in the removal of disinfection byproduct (DBP) precursor material was conducted using composite water created from sample sites within the SWID watershed. Both coagulants were optimized for the removal of NOM. Pragmatic methods of NOM size analysis and its reactivity with chlorine was investigated. UF membranes were used in conjunction with a permeation coefficient model (PCM) to determine an apparent molecular weight distribution of NOM present in the watershed. Individual size classes were assessed for their potential to form trihalomethanes (THMs) upon chlorination. Coagulation using alum and ferric sulfate was assessed to determine removal efficiency of individual NOM size classes under various coagulation scenarios. Finally, UV254 absorbance (UVA) was assessed to determine its potential use as an indicator of DOC concentration in raw and treated water at SWID. Additionally, an investigation into the relationship between specific UVA (SUVA) and THM formation potential (THM-FP) was conducted.

Submitted by Cássia Santos (cassia.bcufg@gmail.com) on 2016-10-05T10:29:36Z No. of bitstreams: 2 Dissertação - Lucas Morais Lôbo - 2015.pdf: 1058045 bytes, checksum: 36335f32e71fcf45a95a64517ccd5f37 (MD5) license_rdf: 0 bytes, checksum: d41d8cd98f00b204e9800998ecf8427e (MD5) / Approved for entry into archive by Luciana Ferreira (lucgeral@gmail.com) on 2016-10-05T10:59:13Z (GMT) No. of bitstreams: 2 Dissertação - Lucas Morais Lôbo - 2015.pdf: 1058045 bytes, checksum: 36335f32e71fcf45a95a64517ccd5f37 (MD5) license_rdf: 0 bytes, checksum: d41d8cd98f00b204e9800998ecf8427e (MD5) / Made available in DSpace on 2016-10-05T10:59:13Z (GMT). No. of bitstreams: 2 Dissertação - Lucas Morais Lôbo - 2015.pdf: 1058045 bytes, checksum: 36335f32e71fcf45a95a64517ccd5f37 (MD5) license_rdf: 0 bytes, checksum: d41d8cd98f00b204e9800998ecf8427e (MD5) Previous issue date: 2015-03-31 / Coordenação de Aperfeiçoamento de Pessoal de Nível Superior - CAPES / Processes of phosphorus adsorption in soil diminish the availability of this nutrient to plants. Humic and fulvic acids present in humic substances (SH) can block the phosphorus adsorption sites in the soil. Thus, this study aimed to verify the effect of adding doses of a SH, availability of P in two types of soils with different adsorption capacities. The treatments consist of four levels of SH (0, 100, 200 and 400 kg.ha-1), two phosphorus sources (Triple superphosphate – SFT and Natural Reactive phosphate – FNR), and three assessment time (7, 14 and 28 days) in two soil types (Red Latosol – LV and Quartzipsamment – NQ). The application of SH altered the availability of P in different soils. Statistical analysis of the data showed a significant difference (P<0,05) for all factors. In LV the P availability increased for both sources, with increasing SH dose up to 14 days. At 28 days the P-available decreases, with no significant difference between doses, but remains superior to treatment without addition of SH. In the NQ the P-available decreases from the addition of the doses of 200 and 400 kg ha-1 of SH up to 14 days of incubation. After 28 days with the degradation of SH values of P-available for these doses begin to increase. These results indicate that the use of SH is effective in increasing the availability of phosphorus in different soils. / Os processos de adsorção de fósforo (P) no solo diminuem a disponibilidade deste nutriente para as plantas. Os ácidos húmicos e fúlvicos presentes nas substâncias húmicas (SH) podem bloquear os sítios de adsorção de fósforo no solo. Desta forma, este estudo teve como objetivo verificar o efeito da adição de doses de SH, na disponibilidade de P em dois tipos de solos com diferentes capacidades de adsorção. Os tratamentos são constituídos de quatro doses de SH (0, 100, 200 e 400 kg ha-1), duas fontes de fósforo (Superfosfato triplo – SFT e Fosfato Natural Reativo – FNR), e três épocas de avaliações (7, 14 e 28 dias), em dois tipos de solos (Latossolo Vermelho – LV e Neossolo Quartzarênico – NQ). A aplicação de SH alterou a disponibilidade de P nos diferentes solos. A análise estatística dos dados mostrou que houve diferença significativa (P<0,05) para todos os fatores. No LV a disponibilidade de P aumentou, para ambas as fontes, com o aumento da dose de SH até aos 14 dias. Aos 28 dias o P-disponível diminui, não havendo diferença significativa entre as doses, porém permanece superior ao tratamento sem adição de SH. No NQ o P-disponível diminui a partir da adição das doses de 200 e 400 kg ha-1 de SH até aos 14 dias de incubação. Aos 28 dias com a degradação da SH os valores de P-disponível para estas doses começam a aumentar. Estes resultados indicam que a utilização de SH é eficiente no aumento da disponibilidade de P em diferentes solos.

The objective of this research was to investigate lead speciation in the soil/sediment-water environment and to better understand how the species affect lead mobility under different environmental conditions. The research involved both field soil and sediment samples as well as standard lead solutions. Field samples were fully characterized and extracted by aqueous and organic solvents. The results were compared and evaluated with the metal speciation model, MINTEQA2. Hydrolytic polymerization and organic complexation studies were conducted with standard lead solutions under controlled experimental conditions. Results of the field samples showed that pH, dissolved cations, ionic strength, dissolved organic matter, and nature of the soil/sediment matrix play major roles in the distribution and mobility of lead (Pb) from contaminated sites. In the aqueous equilibration experiment, the magnitude of Pb2+ solubilization was in the order of pH4>pH7>pH9. The results were in good agreement with MINTEQA2 predictions. An important finding of the research is the detection of Pb polymerization species under controlled experimental conditions. At pH 5.22, Pb polymeric species were formed at rate of 0.03 per day. The role of Pb complexation with organic matter was evaluated in both field and standard samples. Different methodologies showed three types of organically bound Pb. A very small fraction of Pb, in the ppb range, was extractable from the contaminated soil by polar organic solvents. Sequential extractions show that 16.6±1.4 % of the Pb is organically complexed. Complexation of Pb with fulvic acid provided new information on the extent of Pb association with soluble organic matter. The overall results of this research have provided new and useful information regarding Pb speciation in environmental samples. The results, in several instances, have provided verification of MINTEQA2 model's prediction. They also revealed areas of disagreement between the models prediction and the experimental results. A positive note regarding the experimental work done in the research is the verification of the mass balance in all the repeated experiments.

Magister Chirurgiae Dentium - MChD (Oral Medicine and Periodontics) / The aim of this study was to assess whether a mouthwash containing carbohydrate derived fulvic acid, is effective in reducing the salivary microbial count pre-operatively. Endeavours have been made to reduce the risk of infection, bacteraemia and cross-contamination during dental procedures by the application of topical antimicrobial agents. To date chlorhexidine is the most widely evaluated and efficacious agent against oral biofilms but there have been reports of adverse effects ranging from contact dermatitis to severe anaphylactic shock. A new mouth rinse containing carbohydrate derived fulvic acid are reported to have broad spectrum antimicrobial activity against specific oral microbes and Candida albicans with no side effects.

Les propriétés spectrales des composants fluorescents de la matière organique d’un sol naturel ont été étudiées dans les trois fractions physiques ; substances humiques, acide fulvique et acide humique, par la méthode des matrices d’excitation et d’émission de fluorescence couplée à l’algorithme Parallel Factor analysis (PARAFAC). Les modifications spectrales de ces composants ont été suivies (forme et pseudo-concentrations) en présence d’un contaminant de type hydrocarbure aromatique polycyclique (le benzo(a)pyrène (BaP), toxique et à caractère cancérigène) : (1) en faisant varier les volumes d’une solution pure de BaP dans chaque fraction de même concentration en matières organiques, (2) en faisant varier les concentrations en matière organique pour des concentrations fixes de BaP, qui ont été suivies dans le temps. Les résultats ont montré que le BaP influence d’une manière différente les fluorophores présents dans les trois fractions et ont permis de clarifier le type d’interactions avec une fraction ou l’autre. D’autre part, une discussion a été menée sur les paramètres de validation du nombre de composants pour le choix des modèles de PARAFAC. / The spectral properties of the fluorescent components of the organic matter of a natural soil were studied in the three physical fractions; humic substances, fulvic acid and humic acid, by the method of the excitation and fluorescence emission matrices coupled to the Parallel Factor Analysis (PARAFAC) algorithm. The spectral modifications of these components were studied (form and pseudo-concentrations) in the presence of a polycyclic aromatic hydrocarbon contaminant (benzo (a) pyrene (BaP), toxic and carcinogenic): (1) by varying the volumes of a pure solution of BaP in each fraction having the same concentration of organic matter, (2) by varying the concentrations of organic matter for fixed concentrations of BaP, which were followed over time. The results showed that the BaP influences the fluorophores present in the three fractions in a different way and clarified the type of interactions with one fraction or the other. On the other hand, a discussion was held on parameters for validating the number of components for the selection of PARAFAC models.