Thesis (MScEng (Process Engineering))--University of Stellenbosch, 2006. / South Africa has a variety of sources for humic substances that may be utilised for the large-scale production of specialised fertilizers. Humic substances are dark coloured fully decomposed remains of plant and animal organic matter. Amongst the sources that were investigated in this study, a 5-weeks old compost (C5W), a 6-weeks old compost (C6W), a compost prepared by Medallion Mushroom farm for the production of mushrooms (CB1), a compost produced as waste material after mushroom production (CB2), recycled water used in compost (i.e. CB1) preparation for mushroom production (“Goodie water,” GW) and black liquor from pulp industry (BL), black liquor showed the best potential for the large scale production of humic acids in South Africa. The quantity and quality of humic acids in these materials were determined by using the basic acid-precipitation method and E6/E6 ratio analyses of the products. Extracting humic acids from black liquor was optimised by comparing three possible variations to the standard humic acid-precipitation method (HAp), namely, lignin extraction/humic acid precipitation method (LHAp), humic acid precipitation/acid treatment method (HApA) and lignin extraction/humic acid precipitation/acid treatment method (LHApA). The method of extraction had a substantial impact on the quantity and quality of humic acids produced. Humic acid precipitation method followed by humic acid precipitation/acid treatment method (HApA) demonstrated high quantities of humic acids compared to lignin extraction/humic acid precipitation method (LHAp) and lignin extraction/humic acid precipitation/acid treatment method (LHApA). Analyses such as Fourier Transform Infrared (FTIR) spectroscopy, Ultraviolet Visible Spectroscopy (UV-VIS), High Performance Liquid Chromatography (HPLC) and Elemental Analysis demonstrated that the quality of humic acids produced from black liquor was similar to those reported previously. The type of material (e.g. softwood, hardwood and bagasse) used for black liquor production significantly affected the elemental and molecular composition of humic acids produced. The quality of humic acids produced was affected by both lignin extraction and acid treatment. However, chemical analyses indicated that the features of the humic acids extracted from black liquor correlated with their lignin origin. Humic acids from hardwood and softwood black liquor had a low nitrogen and high sulphur content compared to those extracted from black liquor produced from bagasse material. Although chemical and instrumental analysis of humic acids was quite reasonable for all humic acids produced, LHAp method was favoured for the extraction of humic acids from pine liquor due to the high quantity of humic acids produced (low S and ash contents). The humic acids extracted by means of HAp method and HApA had a positive effect on plant growth, when extracted from bagasse and Eucalyptus black liquors. Humic acids extracted by HAp from pine liquor had an inhibitory effect on plant growth. A possible process flow for the large-scale production of humic acids from black liquor was formulated. The possible process flow indicated that with the amounts of black liquor produced from pulp industry production of humic acids in South Africa is a possibility. Nevertheless, there is still more that needs to be done to investigate the cost effectiveness of this production prior its implementation. HAp method was most suitable for the production of humic acids from Eucalyptus and bagasse liquors in terms of quantity and plant response but LHAp method was more suitable for the production of humic acids from pine liquor in terms of both quantity and quality.

Das Verfahren zur Bestimmung von Koc-Werten nach OECD Richtlinie 121 ist zur Abschätzung der Sorptionskoeffizienten einzelner Stoffklassen gut geeignet. Die komplexen Wechselwirkungen eines Stoffes mit einer Matrix bei dem Sorptionsprozess konnten durch die Erweiterung des Kalibrierdatensatzes und den zusätzlichen stationären Phasen besser dargestellt werden. Die empirische Annahme der Kapazitätsfaktorensumme aus Cyano-Phase, Diol-Phase und Amino-Phase berücksichtigt die Wechselwirkungen von polaren Stoffen mit polaren Phasen und kann zur Bestimmung des Sorptionskoeffizienten weiterer Stoffklassen (z.B.: Amine, Alkohole) unter OECD-Bedingungen angewendet werden. Der Vorteil dieser Bestimmungsmethode ist, dass der Sorptionskoeffizient Koc unter umweltrelevanten Versuchsbedingungen ermittelt wurde und weitere Parameter wie zum Beispiel die pH-Wert-Abhängigkeit untersucht werden können. Auch eine hohe Reproduzierbarkeit des Verfahrens ist gewährleistet, da die verschiedenen HPLC-Säulen kommerziell erhältlich sind. Ein großer Nachteil der Bestimmungsmethode ist die einfache Struktur der Sorbensmatrizes, welche die Komplexität der Umwelt- bzw. Bodenmatrix nur bedingt wiedergeben können. Weiterhin ist die Bestimmung des Sorptionskoeffizienten mittels der drei unterschiedlichen HPLC-Säulen zeitaufwendiger als Sorptionsversuche mit einem Sorbensmaterial. Aus diesem Grund wurde in weiteren Sorptionsversuchen ein Sorbens gesucht, welches die natürlichen Sorptionsprozesse besser abbildet. Für das Beurteilen des Sorptionsverhaltens von organischen Verbindungen an natürlichen Sorbentien wurden in Batchversuchen die Sorptionskoeffizienten bestimmt. Mit dem Festlegen der Sorptionsparameter (z.B.: Sorptionskinetik, Sorbensmenge, Extraktionszeit) liegt ein valides Verfahren zur Aufnahme von Sorptionsisothermen vor. Von den verschiedenen Sorptionsmatrizes bilden die Huminsäuren den Sorptionsprozess von organischen Stoffen an natürlichen Böden am besten ab. Die Aldrich-Huminsäure wurde als Sorbens für die Durchführung von Säulenversuchen ausgewählt, da für diese Sorptionsmatrix die Sorptionskoeffizienten mit Literaturdaten am besten übereinstimmen. Für die Anwendung eines weiteren Analysenverfahrens wurde die Säulenmethode mit einer immobilisierten Aldrich-Huminsäure-Silikagel-HPLC-Säule durchgeführt. Die Aldrich-Huminsäure-immobilisierte-stationäre-Phase wurde durch eine mehrstufige organische Synthese unter inerten Bedingungen hergestellt. Zur Verifizierung der eingesetzten Huminsäure-Säule wurden die Stabilität der Matrix mit der theoretischen Bodenzahl N, des Säulendrucks und der Kapazitätsfaktor eines Kontrollstoffes erfolgreich überprüft. Die Porösität der Säulenmatrix, der organische Anteil des Sorbens und die Leitfähigkeit der mobilen Phase wurden als weitere Versuchsparameter überprüft, und es wurde darauf geachtet, dass umweltrelevante Bedingungen bei den Sorptionsversuchen vorliegen. Das HPLC-Verfahren wurde durch die hohe Übereinstimmung zwischen experimentellen Koc-Werten der Aldrich-Huminsäure und den Koc-Literaturwerten aus Batchversuchen mit Böden für neutrale organische Stoffe verifiziert. Auch beim Vergleich der Sorptionsergebnisse von verschiedenen Huminstoff-Matrizes besitzt die Aldrich-Huminsäure die Koc-Werte mit der größten Übereinstimmung mit Literaturdaten. Zur Beurteilung des Sorptionsverhaltens eines Stoffes in der Umwelt wurde die Einteilung von Höltig erweitert. Zum Treffen einer Aussage über das Sorptionsverhaltens eines Stoffes wurde neben dem log Kow auch der log Koc verwendet und für ionische Stoffe in Sorptionsklassen eingeteilt. Für 30 umweltrelevante und toxische Stoffe ohne Sorptionskoeffizient wurde ein Koc-Wert ermittelt und das Sorptionsverhalten nach dem erweiterten Hölting-Modell abgeschätzt. Dabei zeigten 2,6-Di-t-butyl-p-benzochinon, Epoxiconazol und Chalconepoxid nach dem Modell ein relevantes Sorptionsverhalten (log Koc= 2,39 bis 3,18). Für einen Koc-Datensatz von 85 Stoffen wurde mit dem Aldrich-Huminsäure-Säulenverfahrens ein Abraham-Modell aufgestellt. Das Modell liefert die signifikanten Phasenparameter e, s, b, v und und hohe Regressionskoeffizienten (r2=0,91, q2cv= 0,89). Demnach ist das aufgestellte Abraham-Modell für 16 Stoffklassen sehr gut geeignet, die Sorptionskoeffizienten vorherzusagen. Auch der Vergleich mit dem Abraham-Modell von Nyguyen (2005) zeigt, dass die Aldrich-Huminsäure die Sorptionseigenschaften von Böden sehr gut abbilden kann. Für eine Vielzahl an Stoffen lagen keine Literaturwerte vor, so dass mit Hilfe der HPLC-Säulenmethode zeitnah weitere Stoffklassen in das Abraham-Modell implementiert werden können. Für 40 organische Basen mit einem pKs-Bereich von 0,50 bis 10,69 und einem logKow- Bereich von -0,02 bis 5,51 wurde der Sorptionskoeffizient bei 3 pH-Werten ermittelt. Für 9 organische Basen, welche im untersuchten pH-Wertbereich ausschließlich neutral vorliegen, wurde kein signifikanter Einfluss des pH-Werts auf den Sorptionskoeffizienten ermittelt. Für kationisch vorliegende organische Basen wurde mit steigendem pH-Wert ein zunehmender Sorptionskoeffizient bestimmt. Eine Erhöhung des Sorptionskoeffizienten bei pH 5 und pH 7 beruht auf zusätzlichen ionischen Molekül-Matrix-Wechselwirkungen zwischen organischen Basen und Sorbens. Auch für die organischen Basen, welche im pH-Bereich von 3 bis 7 mit beiden Spezies vorliegen, konnte bei dem pH-Wert 5 oder pH-Wert 7 die größten Sorptionskoeffizienten ermittelt werden. Die starke Zunahme der Sorptionskoeffizienten kann neben hydrophoben Wechselwirkungen auf dem Maximum an ionischen Bindungen bei pH 5 oder pH 7 zwischen der kationischen Spezies der Base und den anionischen Carboxyl-Gruppen der Aldrich-Huminsäure basieren. Für 16 organische Basen, welche im pH-Wertbereich bei pH 7 neutral und bei pH 3 ionisch vorliegen, wurde ein linearer Zusammenhang zwischen log Koc.n und log Koc.ion aufgestellt. Für die Annahme, das für einen Stoff der Sorptionskoeffizient einer Spezies ermittelt wurde, gilt die Näherung dass mindestens 90 Prozent der Spezies vorliegen müssen. Das Modell zur Berechnung des pH-abhängigen Sorptionskoeffizienten beruht auf 55 log Koc(pH)-Werten von organischen Basen. Für die Anwendung des Modells muss eine organische Base im untersuchten pH-Wertbereich als neutrale Spezies vorliegen. Bei einem Vergleich der experimentellen Sorptionskoeffizienten mit den berechneten Werten von Franco stellte sich heraus, dass das Literaturmodell zur Vorhersage des Koc(pH) nur bedingt geeignet ist. In zukünftigen Arbeiten kann das erstellte Abraham-Modell für eine noch bessere praxisbezogene Anwendung auf weitere umweltrelevante Stoffklassen erweitert werden. Zur Erstellung eines Gesamtmodells für ionisch und neutral vorliegende organische Basen müssen pH-abhängige Sorptionskoeffizienten weiterer Basen ermittelt werden.

The main objective of this study was to improve our understanding of biological filtration (biofilm type) treatment for manganese (Mn) removal in drinking water. Biological filtration treatment involves biofilms of Mn(II)-oxidizing microorganisms attached to solid filter material that remove and immobilize dissolved Mn(II) in raw water by conversion to black MnO2(s) precipitates. Mn-biological filtration is an emerging green technology that can serve as an alternative to conventional physicochemical treatments but its full potential is hindered by various factors. These include lack of understanding the: (1) optimal removal conditions for Mn, (2) mechanisms for Mn releases of the accumulated Mn in the biofilter, and (3) effects of recalcitrant natural organic matter (NOM) on biofiltration. Confounding these issues is the unknown identity of the diverse microbial communities which occupy the biofilms attached to the filter media. To investigate these issues, biological Mn removal was studied in laboratory bench scale reactors using a new Mn(II)-oxidizing bacterium isolate, Pseudomonas Putida EC112. The main research hypothesis formulated that the transition metal catalyst, MnO2(s), can increase the bioavailable carbon and energy from recalcitrant NOM (e.g., humic acids (HA)) to biological filters. Mn and HA can be found in most natural waters, including groundwaters, lakes and streams. To test the hypothesis, the potential for strain EC112 growth and Mn(II) oxidation utilizing the organic substrate products from the oxidation reaction between HA and MnO2(s) was assessed. Biological Mn(II)-oxidation kinetics were investigated in batch (suspended cell) and continuous flow (biofilm) bioreactors at optimal pH and temperature conditions for strain EC112. Batch kinetics was successfully characterized with the Monod model. Continuous flow steady-state kinetics was modeled with a single, zero-order kinetic parameter. Enhanced Mn(II) removal capacity was observed for strain EC112 in batch and continuous flow reactors in the presence of HA and MnO2. The effect of MnO2(s) on HA biodegradability was studied and optimal conditions for biodegradation were identified. Biofilter Mn(II) releases were observed during the continuous flow bioreactor experiments. Release conditions were identified and releases modeled using pseudo first-order kinetics. Changes in HA structure induced by MnO2(s) oxidation were studied with Fourier transform infrared (FT-IR) and proton nuclear magnetic spectroscopy (1H-NMR).

Addition of alkalinity to acid mine drainage (AMD) results in the neutralisation of acidity and precipitation of dissolved metals as insoluble hydroxides. Two aspects of the current AMD treatment practice at the Stockton Mine could be enhanced. Firstly, residual water quality may be poor due to unreacted alkalinity reagents, particularly CaCO3, resulting in poor water clarity and elevated suspended solids (SS). Secondly, neutralisation to circum-neutral pH may not avoid the discharge of residual metals (Ni and Zn) due to incomplete adsorption and hydroxide precipitation. The aim of this project was to enhance the conventional neutralisation of AMD through addition of humic substances (HS) to reduce residual SS and trace metal concentrations. Humic substances are organically derived and have a high molecular weight. Functional groups on the surface of HS are capable of binding dissolved metals, forming HS-metal complexes. Incorporation of HS complexed metals into settling floc could result in increased metal removal from the dissolved phase. Modified jar testing was used to investigate the effects of HS addition before, after and during (pH 4.5) neutralisation of AMD in two treatment scenarios at the Stockton Mine; the Blackwater Treatment Plant (BTP) using NaOH and Ca(OH)2 and the Mangatini Stream-sump System (MSS) using CaCO3. Supernatant samples collected during the sedimentation period were analysed for basic water quality parameters (turbidity and suspended solids) and dissolved (< 0.45 µm) metal concentrations. The addition of HS to the BTP process before (pH 2.8) and during (pH 4.5) neutralisation resulted in HS precipitation. Precipitated HS subsequently acted as a nucleation site, triggering flocculation of precipitating metal hydroxides, resulting in low turbidity and suspended solids (SS) of less than 2 NTU and 5 mg/L, respectively. The addition of HS after neutralisation (pH 7) did not result in HS precipitation. Intermolecular bridging of HS by the divalent Ca resulted in incorporation of HS into floc when neutralised by Ca(OH)2, resulting in low turbidity and SS. However, in NaOH neutralised conditions, the monovalent Na was unable to bridge HS molecules, resulting in HS remaining dissolved and contributing to elevated turbidity and SS of up to 24.4 NTU and 18.4, respectively. The neutralisation efficiency of CaCO3 is relatively low, thus approximately 1000 mg/L CaCO3 remained unreacted in MSS scenarios, resulting in elevated turbidity and SS. When added after neutralisation, dissolved Solid Energy Humic Acid (SEHA) facilitated flocculation of residual CaCO3 SS, resulting in an up to 75% lower suspended solids than CaCO3 neutralisation alone conditions. Although the results are good, the efficiency of SEHA as a polymer compared unfavorably in a cost: benefit analysis to two commercially available polymers for the removal of residual CaCO3. Neutralisation of AMD in control samples resulted in decreased concentrations of the target metal group (Ni, Zn, Cu, Cd, and Pb) by hydroxide precipitation, co-precipitation, and adsorption. Equilibrium speciation modeling showed that the HS-metal binding affinity controlled the effectiveness of HS addition for metal removal. The low HS complexation affinity of Ni and Zn resulted in no additional metal removal by HS dosing. The removal of Cu was enhanced by over 50% for SEHA 20 during-neutralisation conditions neutralised by both NaOH and Ca(OH)2. Up to 80% lower Cd concentrations were observed for all HS dose conditions when neutralised by Ca(OH)2. Data for CaCO3 HS dosed metal removal was statistically indeterminate. The high detection limit for Pb made any HS dosed removal enhancement difficult to identify, which was unfortunate as Pb has a high HS complexation affinity (Čežı́ková, Kozler et al. 2001; Milne, Kinniburgh et al. 2003). A simple cost: benefit analysis showed that the additional removal of metals by HS dosing was less efficient than conventional neutralisation alone, on a cost basis. Overall, incorporation of HS into AMD treatment results in improved water quality for CaCO3 neutralisation and lower concentrations of metals with a high HS binding affinity, for some conditions. However, further investigation is required to improve the feasibility of HS incorporation into the AMD neutralisation process.

O presente estudo trata da investigação sobre o uso de um produto inovador, classificado como substâncias húmicas, as quais têm sido estudadas como aditivo alternativo na dieta de bovinos de corte. Assim, o objetivo deste estudo foi avaliar o uso de substâncias húmicas como aditivo na dieta de bovinos Nelore e sua influência no metabolismo ruminal e na síntese de proteína microbiana. Utilizou-se 8 machos canulados e castrados, alocados em baias individuais, com peso vivo de 549 kg (± 45 kg). Os animais foram divididos aleatoriamente em delineamento quadrado latino 4x4 replicado, recebendo tratamentos com níveis crescentes de substâncias húmicas na MS da dieta (0%, 0,45%, 0,9% e 1,35%). Avaliou-se o consumo de matéria seca, pH ruminal, ácidos graxos de cadeia curta, nitrogênio amoniacal, contagem de protozoários, síntese de proteína microbiana e níveis de ureia plasmática no sangue. Não houve efeito (p > 0,05) entre os tratamentos para o consumo de matéria seca, pH ruminal, nitrogênio amoniacal, população de protozoários e níveis de ureia plasmática no sangue. Quanto aos ácidos graxos de cadeia curta, ocorreu efeito linear decrescente nas concentrações de isobutírico e valérico e não houve efeito de tratamento para ácido acético, propiônico, butírico e isovalérico. Obteve-se efeito quadrático na excreção urinária de alantoína, purinas microbianas absorvidas e nos compostos nitrogenados microbianos. A adição de substâncias húmicas até o nível de 1,35% na matéria seca não influenciou os parâmetros ruminais dos animais recebendo uma dieta com 50% de concentrado. Estudos adicionais sobre o uso do produto em maior quantidade na dieta, com maior proporção de concentrados, influência de raças, idade e categoria animal podem contribuir para elucidar os efeitos desse produto como aditivo alimentar. / The present study explore the use of an innovative product, classified as humic substance, which has been studied as an alternative additive for beef cattle diet. Therefore, the objective of this study was to evaluate the use of humic substances as an additive in the diet of Nellore cattle and their influence on ruminal metabolism. Eight cannulated and castrated males were used in individual pens with a live weight of 549 kg (± 45 kg). The animals were randomly allotted into a replicated 4x4 latin square design, receiving treatments with increasing levels of humic substances in the diet (0%, 0.45%, 0.9% e 1.35%). The dry matter intake, ruminal pH, short chain fatty acids, ammoniacal nitrogen, protozoan count, microbial protein synthesis and blood urea levels were evaluated. There was no effect (p> 0.05) between treatments for dry matter intake, ruminal pH, ammoniacal nitrogen, protozoan population and plasma urea levels in the blood. As for short chain fatty acids, there was no treatment effect for acetic, propionic, butyric and isovaleric acid, but it was observed linear decreasing effects on isobutyric and valeric concentrations. There was a quadratic effect on urinary excretion of allantoin, absorbed microbial purines and microbial nitrogen compounds. The addition of humic substances up to the level of 1.35% in DM did not influence the ruminal parameters of the animals receiving diet with 50% of concentrate. Additional studies on the product use considering more challenging ration, with a greater concentrated:forage ratios, animal age and other variations can contribute to clarify the effects of this product as additive.

Orientador: Altair Benedito Moreira / Coorientador: Ademir dos Santos / Banca: César Ricardo Teixeira Tarley / Banca: Eduardo Alves de Almeida / Resumo: Este trabalho teve como objetivo estudar a interações das Substâncias Húmicas (SH) com os metais cobre(II), cromo(III) e cromo(VI) por meio de dois métodos, o da supressão da fluorescência molecular e o sistema de ultrafiltração com fluxo tangencial (SUFT). As SH foram caracterizadas por técnicas espectroscópicas na região do infravermelho e do ultravioleta-visível e por fluorescência molecular. Foram realizadas duas coletas de sedimentos, uma no período de chuva e outra no de seca, sendo coletados em três rios da Bacia Hidrográfica do Turvo/Grande, Rio Preto, Rio Turvo e Rio Grande. O sedimento foi coletado com o auxilio de uma draga manual do tipo Van Veen. As SH foram extraídas de acordo com metodologia oficial sugerida pela Sociedade Internacional de Substâncias Húmicas (SISH). A constante de estabilidade condicional (Kc) foi determinada por meio da supressão da fluorescência e variou de 5,6x10-3 - 1,23 em período chuvoso para o íons cobre, e de 5,5x10-3 - 8,7x10-2 para o período de seca. Quando a Kc foi determinada para o complexo SH-Cr(III) valores de 1,9x10-1-5,2x10-1 e 2,1x10-1-3,5x10-1, foram determinados para o período de chuva e de seca, respectivamente. Por fim a Kc foi determinada para a interação das SH com Cr(VI), de forma geral os valores de Kc foram maiores para o período de chuva. A capacidade complexante (CC) determinada por meio do SUFT para a interação das SH com cobre(II) teve valores que variaram de 4,0x10-1 - 6,3x10-1 mmol Cu g-1 SH e de 1,4x10-1 - 5,3x10-1 mmol Cu g-1 SH para período de chuva e seca, respectivamente. Para o Cr(III) a CC variou de 2,1x10-1 - 9,7x10-1 e de 2,6x10-1 - 8,4x10-1 mmol Cr g-1 SH para o período de chuva e seca, respectivamente. Quando a interação das SH com o Cr(VI) foi estudada por meio do SUFT só foi possível calcular a CC para os pontos... (Resumo completo, clicar acesso eletrônico abaixo) / Abstract: This work aimed to study the interactions of humic substances (HS) with copper(II), chromium(III) and chromium(VI), using by two methods, the suppression of the molecular fluorescence and tangential flow ultrafiltration sytem (TFUS). The HS were characterized by spectroscopic thecniques in the infrared and ultraviolet/visible region and molecular fluorescence. There were two sediment samples, one during the wet season and another the dry, being these sediments collected from the three Rivers of the Turvo/Grande drainage basin, Preto river, Turvo river and Grande river. The collection of sediment was carried out with the aid of a manual Van Veen type dredge. The HS were extracted according to the official methodology suggested by the International Humic Substances Society (IHSS). The conditional stability constant (Kc) was determined by suppressing fluorescence and ranged from 5,6x10-3 - 1,23 in the wet season for the copper ions, and of the 5,5x10-3 - 8,7x10-2 to the dry season. When Kc was determined for the complex HS-Cr(III) values of 1,9x10-1-5,2x10-1 e 2,1x10-1-3,5x10-1, were determined for the wet and dry seasons, respectively. Finally, the Kc was determined for the interactions oh HS with the Cr(VI) in geral the Kc values were higher for the wet season. Complexant capacity (CC) was determined by means of TFUS for the interactions of the HS with Copper(II) the values ranged from 4,0x10-1 - 6,3x10-1 mmol Cu g-1 HS and of 1,4x10-1 - 5,3x10-1 mmol Cu g-1 HS for a wet and dry season, respectively. For the Cr(III) CC ranged from 2,1x10-1 - 9,7x10-1 and from 2,6x10-1 - 8,4x10-1 mmol Cr g-1 HS for the wet and dry period, respectively. When the interactions oh HS with Cr(VI) was studied by means of TFUS was only possible to calculate the CC for the points NRP and CAPRP, as for others... (Complete abstract click electronic access below) / Mestre

A produção de lodo de esgoto vem aumentando a cada dia nas estações de tratamento, e a sua disposição final é um problema a ser resolvido. Uma das alternativas encontradas para a disposição final desses resíduos com benefícios ambientais e principalmente econômicos é a reciclagem agrícola, devido a sua composição em termos de matéria orgânica e nutrientes para as plantas. O objetivo deste trabalho foi avaliar os efeitos da adição do lodo de esgoto na matéria orgânica do solo, em um experimento de curto período de duração. As amostras utilizadas neste experimento foram coletadas na Fazenda Retiro, município de Monte Azul Paulista/SP, em áreas com cultivo de citros. O experimento foi composto de 5 tratamentos, uma testemunha e 4 doses de logo de esgoto. Além dos 5 tratamentos também foram amostrados o solo de mata (referência) e lodo de esgoto. Dessas amostras foram extraídos os ácidos húmicos (AH). Foram avaliadas as alterações ocorridas nas estruturas dos AH quanto aos teores de carbono, composição de grupos funcionais, número de radicais livres do tipo semiquinona e grau de humificação. O solo in natura também foi avaliado quanto aos teores de carbono e grau de humificação da matéria orgânica (MO). Para isso, foram utilizadas técnicas como análise elementar, TOC e espectroscopia de EPR, 13C RMN, FTIR, UV-Vis, Fluorescência e FIL. Através dos resultados de análise elementar, foi possível notar que não houve alterações na estrutura dos AH após a adição de lodo de esgoto, podendo ser comprovado através dos espectros de FTIR e 13C RMN, onde não foram observadas diferenças significativas para os diferentes tratamentos. A adição de lodo de esgoto em solos sob cultivo agrícola, entretanto, incorporou MO fresca, pois quando se compara o solo testemunha e o solo que recebeu a dose mais alta de lodo observa-se um aumento de 75% no carbono orgânico do solo. O AH do lodo de esgoto possui um caráter bastante alifático e em sua estrutura uma considerável quantidade de radicais livres do tipo semiquinona. Ao ser adicionado ao solo, observa-se que modifica a concentração do número de radicais livres do tipo semiquinona sem alterar os grupos funcionais do AH do solo. Portanto, no sistema estudado, a adição de lodo de esgoto mostra que o número de radicais livres do tipo semiquinona presentes no solo não é proporcional ao grau de humificação da MO do solo. Os resultados demonstraram que a espectroscopia de fluorescência tanto em solução como a Induzida por Laser forneceu dados coerentes à cerca do grau de humificação da MO. Foi possível observar uma diminuição no grau de humificação no solos submetidos à adição de lodo de esgoto, aproximando-se do solo de mata utilizado como referência. A concentração de carbono no solo aumentou, mesmo depois de ter sido interrompida a aplicação por 2 anos, e o grau de humificação da MO diminuiu, sendo menor ainda do que o solo de mata utilizado com referência. Portanto, podemos considerar este tipo de manejo onde se utiliza lodo de esgoto para condicionamento do solo apropriado tanto do ponto de vista ambiental quanto do ponto de vista agronômico. / The production of sewage sludge increases daily in treatment stations and definitive disposal is a problem to be resolved. One of the alternatives found to dispose such residues, with environmental and economic benefits, is agricultural recycling, owing to its organic composition and plant nutrients. The objective of the present work was to asses the effects of waste sludge addition to soil organic matter in an experiment of short duration. The samples used in this experiment were collected from Fazenda Retiro, a municipality of Monte Azul Paulista/SP, in an area that has citrus plantations. The experiment was composed of 5 treatments, reference soil and 4 sewage sludge doses. In addition to the 5 treatments, the forest soil (reference) and sewage sludge were also sampled. From these samples humic acids (HA) were extracted. The alterations that occurred in the HA structures were assessed regarding ratios of carbon, composition of functional groups, number of semiquinone-type free radicals and rate of humification. In natura soil was also assessed regarding carbon ratio and rate of humification of organic material (OM). Thus, techniques as elementary analysis, TOC and EPR spectroscopy, 13C RMN, FTIR, UV-Vis, Fluorescence and FIL were used. By means of elementary analysis results, it was possible to notice that there was no alteration in the HA structure after addition of sewage sludge, therefore, verifying through FTIR and 13C RMN spectra no significant differences observed for the different treatments. However, addition of sewage sludge in agricultural cultivated soils incorporated fresh OM, since when comparing the reference soil and the soil that received the highest dose of sludge, an increase of 75% is observed in the organic carbon of the soil. The HA of the sewage sludge has a very aliphatic characteristic and in its structure, a considerable quantity of semiquinone-type free radicals. It is observed that when added to the soil, it modifies the concentration of the number of semiquinone-type free radicals, without altering the HA functional groups of the soil. Therefore, in the studied system, addition of sewage sludge demonstrates that the number of semiquinone-type free radicals found in the soil is not proportional to the rate of OM humification of the soil. The results demonstrated that fluorescence spectroscopy in solution, as well as Laser-Induced fluorescence of whole soil, provided coherent data concerning the rate of OM humification. It was possible to observe reduction in the rate of humification in soils submitted to sewage sludge, in close approximation to the forest soil used as reference. The carbon concentration in the soil increased, even after interrupting application for 2 years, and humification degree of OM diminished, proving to be less than the forest soil used as reference. Thus, we can consider this type of management, when sewage sludge is used to condition soil, as appropriate from an environmental point of view, as well as from an agronomical one.

Neste trabalho efetuou-se um detalhado estudo metodológico das técnicas empregadas para a caracterização espectroscópica e cromatográfica dos ácidos húmicos. Neste estudo demonstrou-se que outros fatores, além de características intrínsecas dos ácidos húmicos, podem afetar os resultados obtidos pelas diferentes técnicas espectroscópicas utilizadas. Dentre estes fatores o mais importante foi o íon vanadila (VO2+) residual que afetou drasticamente os resultados das análises espectroscópicas levando à supressão: dos sinais de RMN de 13C de grupos hidrofílicos; dos sinais de RPE dos radicais livres orgânicos; e da intensidade de fluorescência. Pela supressão seletiva dos sinais de RMN de 13C dos grupos carboxilas e daqueles associados a carboidratos foi possível inferir que estas estruturas possivelmente estejam diretamente envolvidas na complexação do VO2+, assim como a supressão dos sinais de fluorescência e de RPE dos radicais livres orgânicos indicaram que estes radicais e estruturas fluorescentes também podem estar envolvidas na complexação deste íon ou então o efeito do íon paramagnético pode difundir-se facilmente pela estrutura dos ácidos húmicos. Adicionalmente, os ácidos húmicos com maior conteúdo de VO2+ apresentaram um maior tamanho molecular aparente, indicando um possível efeito agregante deste íon. A análise multivariada dos dados obtidos possibilitou o isolamento destes efeitos do VO2+ e as novas variáveis obtidas pela técnica dos componentes principais, independentes do conteúdo deste íon, indicaram que o cultivo mais intenso do solo levou ao acúmulo relativo de estruturas mais recalcitrantes e com maiores conteúdos de estruturas associadas à lignina e C-Alquila de cadeia longa. Além disto, observou-se que o sinal dos radicais livres orgânicos dos ácidos húmicos era devido à pelo menos dois centros paramagnéticos distintos sendo que o VO2+ suprimiu preferencialmente o sinal com maior valor-g, atribuído a radicais livres orgânicos onde o elétron desemparelhado estaria delocalizado sobre átomos de oxigênio. / In this work it was realized a detailed methodological studies of spectroscopic and chromatographic techniques that were applied in the humic substances characterization. In these studies it was demonstrated that, besides the intrinsic characteristics of humic substances, there are other factors which can affect the results obtained with the different spectroscopic techniques utilized. Among these factors, the residual vanadyl ion (VO2+) affected drastically the spectroscopic results causing the suppression of: 13C NMR signals of hydrophilic groups; EPR signals from organic free radicals; and the fluorescence intensity. By the selective suppression of 13C NMR signals from carbohydrates and carboxyl groups it was proposed that these structures could possibly be directly involved in the VO2+ complexation. The suppression of fluorescence signals and EPR ones from organic free radicals indicated that or these radicals and the fluorescent structures can also be involved in the VO2+ complexation, either the paramagnetic ion effect can diffuse through the humic substances structures. In addition, the increase of VO2+ contents resulted in a higher apparent molecular size indicating a possibly aggregating effect of this ion. The multivariate analysis from the obtained data allowed the isolation of these effects from VO2+. The new variables obtained by the principal components technique, independent from that ion content, indicated that the most intense cultivation of the soil lead to the relative accumulation of more recalcitrant structures associated to lignin and long chain C-alkyl. Besides this, we observed that the organic free radicals signal from humic acids was due to at least two paramagnetic centers. The residual VO2+ suppressed preferentially the signal with the highest g-value. This signal was assignment to organic free radicals where the unpaired electron could be delocalized on oxygen atoms.

Investigou-se a influência de íons metálicos Al(III), Ca(II), Fe(III), Pb(II), Cu(II) e Cr(III) (10-6 a 10 -3 mol L-1 na intensidade relativa de fluorescência (IRF) do ácido húmico (AH, 10 mg L-1). os íons Cu(ii), Pb(II) e Cr (III) produziram um efeito de supressão, enquanto os íons Fe(III), Al(III) e Ca(II) não influenciaram significativamente nos valores de IRF. A partir dos valores de IRF foram calculadas a constante de estabilidade (K) dos complexos e a capacidade complexante do AH com Cu(II), Pb(II) e Cr(III). Os valores de K seguiram a ordem: Cr(III)> Pb(II) > Cu(II) e a capacidade complexante: Cr(III) ~ Pb(II)> Cu(II). Desenvolveu-se um novo método analítico baseado na reação quimiluminescente da oxidação do AH com peroxomonosulfato de potássio (PMS; 0,6 mol L-1</SUP) ) em meio básico (NaOH 1,0 mol L-1 ). A intensidade máxima de radiação emitida (Imáx ) e a área em função do tempo foram lineares com a quantidade de AH em solução na faixa de 0,5 a 20 mg L-1, com o limite de detecção de 0,24 mg L-1 , com limite de detecção de 0,24 mg L-1 . Um estudo comparativo foi realizado utilizando-se H2O2 (0,58 mol L-1 na presença de CH2O (0,44 mol L-1) em meio básico (NaOH 0,16 mol L-1) com limite de detecção de 0,4 mg L-1. As adições dos íons Cl-, NO3- , PO43- , CO32- , Fe(III), Cu(II), Cr(III) e Ca(II) na reação quimiluminescente de AH com PMS, não interferiram significativamente no sinal. Adições de 50 mg L-1 de Co(II) ou Mn(II) à solução de AH Aldrich, na forma de complexos de EDTA ou cloretos, aumentaram o valor Imáx devido à formação de espécies fortemente oxidantes como SO5°-, SO4°- HO° durante a reação de decomposição do PMS. O método foi aplicado para determinar a concentração de AH em amostra de água do Rio Miranda - MS, obtendo-se valores entre 2,9 a 12,3 mg L-1 . As reações de oxidação, com emissão de radiação, de alguns compostos orgânicos com PMS em meio básico foram estudadas. Com os polifenóis obtiveram- se intensidades de radiação mais significativas e os valores de área seguiram a seguinte ordem: floroglucinol >> ácido fúlvico > ácido húmico > resorcinol > ácido pirogálico > catecol > hidroquinona. Desta forma, como polifenóis existem na estrutura de substâncias húmicas, acredita-se que essas porções da molécula devem ser as responsáveis pela produção de quimiluminescência. / The influence of Al(III), Ca(II), Fe(III), Pb(II), Cu(II), and Cr(III) metal ions (10-6 to 10-3 mol L-1) on the relative fluorescence intensity (RFI) of humic acid (HA, 10 mg L-1) was investigated. Cu(II), Pb(II), and Cr(III) ions produced a quenching effect, while Fe(III), Al(III), and Ca(II) ions did not significantly interfere with RFI values. Stability constants (K) and complexing capacities of HA with Cu(II), Pb(II), and Cr(III) were obtained using RFI values. Stability values of complexes followed the order: Cr(III)> Pb(II) > Cu(II) and the complexing capacity values: Cr(III) ~ Pb(II) > Cu(II). A new analytical method was developed based on the chemiluminescent oxidation of HA by peroxymonosulfate (PMS; 0.6 mol L-1) in basic medium (NaOH 1.0 mol L-1). The intensity of radiation emission (Imax) and area vs. time were linear functions of HA concentration range of 0.5-20 mg L-1. The detection limit was 0.24 mg L-1. A comparative study was conducted using H2O2 (0.58 mol L-1) in the presence of CH2O (0.44 mol L-1) in basic medium (NaOH 0.16 mol L-1). The detection limit was 0.4 mg L-1 of HA. The addition of Cl-, NO3-, PO43-, CO32-, Fe(III), Cu(II), Cr(III), and Ca(II) to the chemiluminescent reaction of HA with PMS did not interfere with the signal. The addition of 50 mg L-1 Co(II) or Mn(II) (as EDTA complexes or chloride salts) to the HA sample enhanced radiation emission, due to the formation of strong oxidant species such as SO5o-, SO4o-, and HOo during PMS decomposition reaction. This method was applied to determine HA concentration in a sample of river water (Miranda River - MS), obtaining values between 2.9 and 12.3 mg L-1. Oxidation reactions of some organic compounds by PMS in basic medium were studied, which produced radiation emission. Polyphenols produced the highest emissions and the area values followed the order: phloroglucinol> fulvic acid> humic acid> resorcinol> pyrogalic acid> cathecol> hydroquinone. Since polyphenolic groups are supposed to exist within humic acid structure, those portions of the molecule are most likely to be responsible for that chemiluminescence.

Este estudo teve como objetivo avaliar a interação entre substâncias húmicas e xenobióticos através de estudos ecotoxicológicos. O principal foco foi avaliar a resposta entre diferentes níveis tróficos em organismos aquáticos (fitoplanctônicos, zooplanctônicos, peixes e macroinvertebrados bentônicos) e terrestres (vegetais superiores, insetos e anelídeos) avaliando os efeitos diretos e indiretos das SH e de sua mistura com xenobióticos sobre os organismos. O reconhecido efeito das SH aumentarem ou reduzirem o efeito tóxico de algumas substâncias foi estudado. Os principais pontos para discussão são: a) SH podem reduzir ou estimular o crescimento algal (P. subcapitata); b) A presença de SH podem proteger os organismos contra efeitos tóxicos de metais, no entanto, a presença de Cd/Cu afeta negativamente o crescimento de C. xanthus. d) Em uma análise integrada de processos de remediação solo/água, a presença de SH afetou negativamente ou positivamente os efeitos tóxicos da atrazina em alguns organismos. A significância das SH como tecnologia é discutida. / This study focuses the interaction of humic substances and xenonbiotics, throw ecotixicological studies. The main point was quantify and qualify the ecotoxicological responses of several throphic levels of freshwater (algae, zooplankton, fishes and benthic organisms) and soil organisms (higth plants, insects and annelids) analyzing the direct and indirect effects of humic substances (HS) and their mixture on organisms. The recognized ability of HS on improve or reduce the toxic effect of same substances has been studied. The main points of discussion are: a) humic can be both reduce or stimulate the algal growth (P. subcapitata); b) The presence of HS can be protect aquatic organisms to negative effects of metals. However, the presence of mixture of Cd/Cu affect negatively the growth of C. xanthus; d) In a integrated analysis of remediation process in soil/water microcosm, the presence of HS displayed negative or positive effects on atrazine toxicity for some organisms. The value of humic technology was discussed.