The main objective of this thesis is to judge the barrier properties of hydrogels. It was examined in total six kinds of agarose hydrogels, of which five kinds of gels was enriched with humic acids isolated from various sources. Humic acids were selected from IHSS standards, specifically Leonardite, Elliott Soil, Suwannee River, Pahokee Peat and Nordic Lake. Using UV-VIS spectrometry, copper ion concentrations were used to serve as a diffusion solution. Results of diffusion coefficients were evaluated by several diffusion methods. The method of diffusion in the plane of the board and three possible diffusion solutions of the constant source were used.

<p>Od primenjenih elektrokinetičkih tehnika:<br />konvencionalna, elektrodijalitička (uz primenu CEM), zatim tretman<br />uz izmenu polariteta na elektrodama, primena pomeranja anode ka<br />katodi, bipolarnih elektroda kao i povećane dužine katodnog prostora,<br />na uzorku Ni zagađenog kaolina (model matriks) najveću efikasnost<br />uklanjanja Ni pokazale su primena pomeranja anode ka katodi (51%<br />odnosno 82% bez uračunavanja katodnog regiona kaolina) i primena<br />bipolarnih elektroda uz povećani katodni prostor (45%).<br />Primenom bipolarnih elektroda uz povećan katodni prostor kao<br />unapređene EK tehnike preči&scaron;ćavanja sedimenta sa visokim ANC<br />postignute su efikasnosti od 44% za uklanjanje Ni odnosno 36%,<br />42% i 43% za uklanjanje Ni, Cd i Pb u sme&scaron;i, redom. Ove efikasnosti<br />su približno dvostruko veće u odnosu na efikasnosti konvencionalnih<br />tretmana, a uviđa se neznatni uticaj prisustva Cd i Pb na efikasnost<br />uklanjanja Ni. Procena rizika na osnovu različitih kriterijuma utvrdila<br />je da je sediment zagađen Ni nakon tretmana siguran za okolinu.<br />Sediment zagađen Ni, Cd i Pb je prema sadržaju Ni i Pb siguran po<br />okolinu, ali se poređenjem različitih kriterijuma procene rizika koji su<br />kori&scaron;ćeni u toku rada dobijaju informacije koje se u manjoj ili većoj<br />meri potvrđuju &scaron;to ukazuje na neophodnost postojanja jedinstvenih i<br />sveobuhvatnih kriterijuma procene rizika. Navedeno potvrđuje da je<br />primena bipolarnih elektroda uz povećan katodni prostor efikasna<br />tehnika preči&scaron;ćavanja sedimenta koji je zagađen Ni i Pb pri<br />koncentracijama koje su navedene u radu.<br />Primenom pomeranja anode ka katodi uz povećan katodni<br />prostor kao unapređene EK tehnike preči&scaron;ćavanja sedimenta sa<br />niskim ANC postignute su efikasnosti od 25% za uklanjanje Ni<br />odnosno 17%, 24% i 62% za uklanjanje Ni, Cd i Pb u sme&scaron;i, redom.<br />Ove efikasnosti su približne za Ni odnosno dvostruko i trostruko veće<br />za Cd i Pb, redom u odnosu na efikasnosti konvencionalnih tretmana.<br />Može se utvrditi da je efikasnost unapređenog procesa značajno<br />povećana, ali poređenjem krajnih koncentracija metala u sedimentu<br />nakon tretmana sa kriterijumima procene rizika, utvrđeno je da jedino<br />prema sadržaju Pb sediment se može smatrati sigurnim po akvatičnu<br />sredinu dok prema sadržaju ostalih metala spada u visoko rizičnu<br />klasu (&gt;50%).</p> / <p> As the result of applying electrokinetic techniques:<br /> conventional, electrodialytic, treatment with electrode polarity<br /> exchange, moving anode, using bipolar electrodes and increased<br /> cathodic compartment length, on Ni contaminated kaolin (model<br /> matrix) the most efficient were moving anode technique (51% or<br /> 82% without calculating the cathode region of kaolin) and using<br /> bipolar electrodes and increased cathodic compartment length (45%).<br /> Using bipolar electrodes and increased cathodic compartment<br /> length as enhanced EK technique for remediation of sediment with<br /> high ANC resulted in 44% of Ni removal and 36%, 42% i 43% for<br /> removal of Ni, Cd and Pb, respectively. This technique nearly<br /> doubled efficiency after conventional treatment and there is slight<br /> influence of Cd and Pb on Ni removal. Risk assessment based on<br /> different criteria determine that Ni contaminated sediment is safe for<br /> the environment after EK treatment. According to Dutch standards it<br /> is classified as Class 1/2. Ni, Cd and Pb contaminated sediment is<br /> safe for the environment according to Ni and Pb content after EK<br /> treatment according to Dutch standards but comparing the risk<br /> assessment arise from different criteria in some cases it do not<br /> provide the same information. This indicates that it is of great<br /> importance to develop unique risk assessment criteria. According to<br /> the results using bipolar electrodes and increased cathodic<br /> compartment is efficient EK remediation technique of Ni and Pb<br /> contaminated sediment at the concentrations used for these<br /> investigations.<br /> Using the moving anode technique and increased cathodic<br /> compartment length as enhanced EK technique for remediation of<br /> sediment with low ANC resulted in 25% of Ni removal and 17%,<br /> 24% and 62% for removal of Ni, Cd and Pb, respectively. It can be</p> <p> concluded that efficiencies after enhanced technique compare to<br /> conventional treatments are significantly increased but the final metal<br /> concentrations (except Pb) in sediment after treatment according to<br /> risk assessment criteria are highly hazardous for the environment<br /> (&gt;50%).</p>

In the year 2000, 170 countries decided to stand together and solve some primary and common global problems like poor health, water, and sanitation. Obtaining access to safe drinking water is every individual’s right. The UN defines safe drinking water as “the water required for each personal or domestic use must be safe, therefore free from micro-organisms, chemical substances and radiological hazards that constitute a threat to a person's health” (UNDESA, 2014). This thesis focuses on identifying the number of people who potentially receive spring water from a piped source in rural mountainous areas. There are three significant steps and data requirements which are necessary to meet this study’s objective. These are to: 1) obtain data classifying the various sources of drinking water in each country by specifying the percentage of population served by a particular water in rural and urban areas, 2) determine the number of countries which are undeveloped or developing, and 3) identify specific countries which are defined as mountainous (and thus likely to have spring fed piped water systems) based on elevation and slope in order to estimate the number of people living in mountainous areas. Results show that 183.54 (million) people were estimated to receive piped water from the springs in mountainous areas. Approximately, 34% of the population is from the Eastern Asia and South-Eastern Asia regions, and 33% reside in the Latin America and Caribbean Islands. These were followed by Western Asia and North Africa Regions with 15% and Central Asia and Southern Asia Regions with 14% of their population estimated to receive piped spring water.

<p>U radu je: 1. Određena efikasnost elektrokinetičkih tretmana (konvencionalni tretman, tretman sa izmenom polariteta, tretman sa dve anode i heksagonalni dvodimenzionalni elektrokinetički tretman) koji izuzimaju dodatak agenasa u tretirani sediment, za uklanjanje metala; 2. Ispitan je uticaj diskontinuiteta napajanja strujom (tokom noći), kao i uticaj oscilacija jačine električne energije pri primeni solarnih panela na efikasnost tretmana; 3. Ispitan je uticaj geohemije sedimenta, fizičko-hemijskih promena u sistemu i karakteristika prisutnog zagađenja (oblici pojavljivanja metala, koncentracije) na efikasnost elektrokinetičkog procesa. 4. Izvr&scaron;ena je procena rizika u sistemu sediment/voda pre, tokom i nakon tretmana; 5. Primenjen je matematički model na dobijene rezultate. Na osnovu određene efikasnosti i procene rizika tretmana elektrokinetičke remedijacije na realan problem Velikog Bačkog kanala zaključeno je, da je najbolja opcija dvoanodni tretman u kome se primenjuju solarne panele (e9). Dobijeni rezultati tretmana ukazuju da diskontinuiteti napajanja strujom (tokom noći), kao i uticaj oscilacija jačine električne energije pri primeni solarnih panela nemaju značajnog uticaja na efikasnost procesa. &Scaron;to se tiče, geohemije sedimenta, pokazalo se da ona ima snažan uticaj i da upravo ona određuje fizičko-hemijske promene koje se događaju u sedimentu tokom sprovođenja tretmana elektrokinetičke remedijacije. Ključ uspeha ovih tretmana sedimenta jeste i zadržavanje metala u frakcijama (karbonatna i reducibilna) koje lak&scaron;e migriraju. Primenom matematičkog modela zaključeno je da se mogu predvideti promene koncentracija metala bez sprovođenja eksperimenata, &scaron;to je od krucijalnog značaja za buduća istraživanja.</p> / <p>This work includes: 1. An investigation into efficiency of various electrokinetic treatments (a conventional treatment, and treatments with changing polarity, two anodes and two-dimensional hexagonal electrodes) without the addition of agents to the treated sediment, for the removal of metals; 2. An investigation of the influence of discontinuous (off during the night) and oscillating power supplies on the application of solar panels and their effect on the efficacy of the treatment; 3. A study on the influence of sediment geochemistry, physico-chemical changes in the system and the characteristics of the pollution present (metals speciation and concentration) on the efficiency of the electrokinetic process; 4. A risk assessment of the sediment/water system before, during and after the treatment; 5. Mathematical modelling of the results obtained. Based on the risk assessment and the efficiency of the electrokinetic treatments in the Veliki Backa canal sediment, it was concluded that the best remediation option was a two anode treatment using solar panels (e9). The investigation into the influence of treatments using discontinuous (off during the night) and oscillating power supplies showed they did not have a significant impact on the efficiency of the process. Sediment geochemistry was shown to have a strong influence, determining the physical and chemical changes that occur in the sediment during the implementation of the electrokinetic remediation. The key to success for these treatments is the retention of metals in the fractions (carbonate and reducible) which more easily migrate. It is concluded that the mathematical model can be applied to successfully predict thechanges in the concentration of metals without experimentation, which is of crucial importance for future studies.</p>

This study focuses on engineering whole cell-based biosensors for heavy metal detection. Through the exploitation of metalloregulatory proteins, fabrication of metal ion-responsive biosensors is achieved. Metalloregulatory proteins of the SmtB/ArsR family including arsenite-responsive ArsR, cadmium-responsive CadC, zinc-responsive CzrA, and nickel-responsive NmtR were evaluated as biosensor sensing modules. Characterization of these four metal sensing modules was accomplished through quantification of a reporter green fluorescence protein (gfp) gene. As such, biosensors pCTYC-r34ArsR-pL(ArsOvN)GFP and pCTYC-r34CadC-pL(CadOv1)GFP displayed excellent gfp expression and sensitivity to As(III) and Cd (II), respectively. These two biosensors were consequently selected and successfully implemented in soil bacterium Pseudomonas putida. Lastly, a proof of concept arsenite-responsive genetic toggle switch is proposed utilizing PurRcelR467 (PC47), a cellobiose-responsive gene, and an LAA degradation tag. Overall, this study expands the bank of metalloregulatory bioparts for heavy metal sensing in the aim of constructing an optimized water monitoring system.

No description available.

This thesis focuses on the synthesis and applications of nanoscale zero valent iron (nZVI) in the environmental remediation of contaminants. The polyvalent characteristics of this nanomaterial are evaluated in this work with the study of its application in a wide range of contaminants: heavy metals and pesticides in water medium, and malodorous sulfur compounds present in air streams. Moreover, a novel method of synthesis of encapsulated nZVI from a waste material is presented, which meets the principles of green chemistry and at the same time represents a low-cost method of obtaining nZVI with improved characteristics. Chapter 1 describes the current state of the topics that will be discussed in the rest of the thesis. Specifically, the different mechanisms of contaminant remediation by nZVI are discussed, a summary of the current synthesis methods is presented and the principal modifications of nZVI to improve its characteristics are described. Finally, the limitations of the current techniques are assessed, which will be the starting point of the thesis. In Chapter 2, the application of nZVI to heavy metal removal during long time periods is explored. The contaminants studied are Zn, Cd, Ni, Cu and Cr, which are the most common heavy metals found in ground and wastewater. A delivery-effect of the heavy metal ions that had already been attached to nZVI surface is observed after long reaction times, which is a consequence of the nZVI aging and oxidation. The conditions that influence the delivery-effect are assessed and possible solutions to this detected problem are presented. In Chapter 3, nZVI is applied to the removal of sulfur-based odorous compounds in air streams. The compounds studied are hydrogen sulfide and dimethyl disulfide (DMDS), which are commonly found in wastewater treatment plants. Both nZVI loading and pH are varied to assess their influence on the process. Bimetallic nanoscale particles of Cu/Fe, Ni/Fe and Pd/Fe are synthesized in order to improve the DMDS abatement by the nZVI. The advantages of this new method for odor removal are discussed at the look of the experimental results. Lastly, a pilot scale test was performed in a wastewater treatment plant in order to test the effectiveness of the nZVI in a real application. The nZVI were applied in a scrubber to eliminate the sulfurous compounds from the pre-treatment area of the wastewater treatment plant. Chapter 4 deals with the application of nZVI to the oxidation of non-biodegradable pollutants by the Fenton reaction. Specifically, the effect of pH on the degradation of the herbicide 2,4-dichlorophenoxyacetic acid (2,4-D) is studied. The advantages of using nZVI as a Fenton reagent compared to homogeneous Fenton are described. Furthermore, the addition of UV-light to the process is investigated. Finally, the main degradation intermediates of the reaction are identified and a degradation mechanism is accordingly proposed. In Chapter 5, the presence of polychlorinated dioxins and furans (PCDD/Fs) in the nZVI surface is addressed. Studies have shown that nZVI enhances the formation of such chlorinated compounds during thermal processes, but it is unclear which the origin of the compounds is. It has been suggested that nZVI could possess impurities such as PCDD/Fs in its surface. Therefore, the concentration of PCDD/Fs in both commercial and laboratory-synthesized nanoparticles is analyzed. PCDD/Fs pattern and WHO-TEQ concentrations are also obtained. As an outcome of the results obtained in this chapter, a recommendation for preventing the PCDD/Fs presence in nZVI is given. Chapter 6 is dedicated to the synthesis of carbon-encapsulated nanoparticles using hydrothermal carbonization (HTC) of an agricultural waste, particularly, olive mill wastewater (OMW). This novel method, in addition to meet the green chemistry principles, makes profit of the high polyphenol content of OMW to maximize the fraction of incorporated iron into the nZVI. Moreover, the carbon layer surrounding the nZVI protects it against oxidation and avoids its aggregation. Several HTC conditions are explored to study their implications in the characteristics of the material obtained. A deep characterization of the encapsulated nZVI is also presented in this chapter. In Chapter 7, the applications of the encapsulated nZVI synthesized in Chapter 6 are explored and compared for the same contaminants that have been studied in the previous chapters. Then, the advantages of encapsulated nZVI in comparison with common nZVI are discussed at the end of the chapter, and an estimation of the synthesis costs with this method is addressed. Lastly, in Chapter 8, the main conclusions of the thesis are summarized and suggestions for future work are presented.

Sesbania drummondii seedlings were grown in a medium to which lead (Pb), copper (Cu), nickel (Ni) and zinc (Zn) were added singly and in combinations in order to assess the effects of metal interactions on seedling growth, metal accumulation and anti-oxidative system. S. drummondii growth was significantly inhibited with metal treatments. S. drummondii accumulated substantially higher concentrations of metals in the roots than shoots. The uptake of metals followed the order Pb > Cu > Zn > Ni in roots and Pb > Zn > Cu > Ni in shoots. In addition, uptake of a single metal by S. drummondii was affected by the presence of a second metal, suggesting an antagonistic effect or competition between metals at the plant uptake site. A significant increase in both enzymatic [superoxide dismutase (SOD), ascorbate peroxidase (APX), glutathione reductase (GR)] and non-enzymatic (glutathione) antioxidant was observed in the S. drummondii seedlings exposed to different metal treatments. The enhancement in enzyme activities followed the order of Cu > Ni > Pb > Zn. However, compared to the effect of individual metal, metals in combination increased the enzyme activities to varying degrees.

Disposal and beneficial-use options for street sweeping residuals collected as part of routine roadway maintenance activities in Florida, USA, were assessed by characterizing approximately 200 samples collected from 20 municipalities. Total concentrations (mg/kg or μg/kg) and leachable concentrations (mg/L or μg/L) of 11 metals and a number of organic pollutant groups (volatile organics, semi-volatile organics, pesticides, herbicides, carbamates) in the samples were measured. The synthetic precipitation leaching procedure (SPLP) was performed to evaluate the leachability of the pollutants. From the total metal analysis, several metals (e.g., arsenic, barium, chromium, copper, nickel, lead, and zinc) were commonly found above their detection limits. Zinc was found to have the highest mean concentration of all metals measured (46.7 mg/kg), followed by copper (10.7 mg/kg) and barium (10.5 mg/kg). The metal with the smallest mean concentration was arsenic (0.48 mg/kg). A small fraction of the total arsenic, barium, lead, and zinc leached in some samples using the SPLP; leached concentrations were relatively low. A few organic compounds (e.g., 4,4′-DDT, endrin, and endosulfan II) were detected in a limited number of samples. When the total and leaching results were compared to risk-based Florida soil cleanup target levels and groundwater cleanup target levels, the street sweepings were not found to pose a significant human-health risk via direct exposure or groundwater contamination.

For more than 50 years, heavy metal exposure during pre- or post-natal ontogeny has been known to produce long-lived hyperactivity in rodents. Global brain injury produced by neonatal hypoxia also produced hyperactivity, as did (mainly) hippocampal injury produced by ontogenetic exposure to X-rays, and (mainly) cerebellar injury produced by the ontogenetic treatments with the antimitotic agent methylazoxymethanol or with polychlorinated biphenyls (PCBs). More recently, ontogenetic exposure to nicotine has been implicated in childhood hyperactivity. Because attention deficits most often accompany the hyperactivity, all of the above treatments have been used as models of attention deficit hyperactivity disorder (ADHD). However, the causation of childhood hyperactivity remains unknown. Neonatal 6-OHDA-induced dopaminergic denervation of rodent forebrain also produces hyperactivity - and this model, or variations of it, remain the most widely-used animal model of ADHD. In all models, amphetamine (AMPH) and methylphenidate (MPH), standard treatments of childhood ADHD, typically attenuate the hyperactivity and/or attention deficit. On the basis of genetic models and the noted animal models, monoaminergic phenotypes appear to most-closely attend the behavioral dysfunctions, notably dopaminergic, noradrenergic and serotoninergic systems in forebrain (basal ganglia, nucleus accumbens, prefrontal cortex). This paper describes the various pharmacological models of ADHD and attempts to ascribe a neuronal phenotype with specific brain regions that may be associated with ADHD.