This study investigates translocation of particulate carbon and nitrogen from burned and unburned catchments within New Mexico's Valles Caldera National Preserve following severe wildfire. My research questions are: (1) how much carbon and nitrogen is eroded from burned slopes and re-deposited in debris fans? and (2) how do these quantities compare to fluvial export of particulate carbon and nitrogen from nearby unburned catchments? Results indicate that the ~200 kg ha⁻¹ of nitrogen per depositional area on the debris fans represents ~50 to 100 years' worth of atmospheric inputs. In total, 124 times more carbon and 21 times more nitrogen were deposited on the two fans than was exported in particulate form from all three unburned catchments combined in water year 2012. My findings suggest that post-fire erosion may increase nitrogen loading to downslope environments, with the potential to alter the biogeochemical budgets of both aquatic and terrestrial systems.

Dissolved organic matter (DOM), one of the most complex naturally occurring mixtures, plays a central role in the biogeochemistry and the photochemistry of natural waters. A complete understanding of the environmental role of DOM will come only from the elucidation of the relationship between its structure and function. This thesis presents new work on the separation, characterization, and reactivity of DOM in rainwater, freshwater, and seawater. A new separation technique based on counterbalance capillary electrophoresis was developed for the separation of Suwannee River NOM. A comparative study of the organic content of rainwater was accomplished using nuclear magnetic resonance (NMR) with spectral database matching ,Fourier transform ion cyclotron mass spectrometry (FT-ICR-MS), and comprehensive two-dimensional gas chromatography time-of-flight mass spectrometry (GCxGC-TOFMS). Three complementary, non-overlapping datasets identified of over 400 compounds. Analysis of the FT-ICR-MS data using van Krevelen diagrams and the carbon oxidation state showed variation in the elemental composition and molecular size. Over 50% of the compounds identified in this study were known components of secondary organic aerosol (SOA) and volatile organic carbon (VOCs). Dissolved organic matter (DOM) plays a central role in the photochemistry of natural waters through the production of reactive oxygen species and the triplet excited state of DOM (3DOM*). These reactive species are central to the reactivity, transport, and fate of both natural and anthropogenic chemicals in the environment. Laser flash photolysis (LFP) was used to demonstrate that particulate organic matter (POM) generates a triplet excited state species (3POM*). LFP of seawater from the Pacific Ocean and the Bermuda Atlantic Time Series Station detected similar excited state species from surface to 4535m. Metal speciation has been implicated in the photochemistry of natural waters. Copper immobilized metal affinity chromatography (IMAC) of seawater and freshwater isolated a low and a high affinity fraction that generated excited state transients. Excitation-emission matrix spectroscopy showed that while the seawater fractions were autochthonous, freshwater fractions enriched in chromophoric DOM (CDOM), were allochthonous. The discovery of these different classes of compounds in freshwater and seawater has important implications both for the mineralization of DOM and the removal of xenobiotics in the aquatic environment.

Dissolved organic matter (DOM), one of the most complex naturally occurring mixtures, plays a central role in the biogeochemistry and the photochemistry of natural waters. A complete understanding of the environmental role of DOM will come only from the elucidation of the relationship between its structure and function. This thesis presents new work on the separation, characterization, and reactivity of DOM in rainwater, freshwater, and seawater. A new separation technique based on counterbalance capillary electrophoresis was developed for the separation of Suwannee River NOM. A comparative study of the organic content of rainwater was accomplished using nuclear magnetic resonance (NMR) with spectral database matching ,Fourier transform ion cyclotron mass spectrometry (FT-ICR-MS), and comprehensive two-dimensional gas chromatography time-of-flight mass spectrometry (GCxGC-TOFMS). Three complementary, non-overlapping datasets identified of over 400 compounds. Analysis of the FT-ICR-MS data using van Krevelen diagrams and the carbon oxidation state showed variation in the elemental composition and molecular size. Over 50% of the compounds identified in this study were known components of secondary organic aerosol (SOA) and volatile organic carbon (VOCs). Dissolved organic matter (DOM) plays a central role in the photochemistry of natural waters through the production of reactive oxygen species and the triplet excited state of DOM (3DOM*). These reactive species are central to the reactivity, transport, and fate of both natural and anthropogenic chemicals in the environment. Laser flash photolysis (LFP) was used to demonstrate that particulate organic matter (POM) generates a triplet excited state species (3POM*). LFP of seawater from the Pacific Ocean and the Bermuda Atlantic Time Series Station detected similar excited state species from surface to 4535m. Metal speciation has been implicated in the photochemistry of natural waters. Copper immobilized metal affinity chromatography (IMAC) of seawater and freshwater isolated a low and a high affinity fraction that generated excited state transients. Excitation-emission matrix spectroscopy showed that while the seawater fractions were autochthonous, freshwater fractions enriched in chromophoric DOM (CDOM), were allochthonous. The discovery of these different classes of compounds in freshwater and seawater has important implications both for the mineralization of DOM and the removal of xenobiotics in the aquatic environment.

Magistro darbe yra tiriama Kauno rajone, Mitkūnų kaime esančių 5 šachtinių šulinių vandens užterštumas azoto junginiais ir organinėmis medžiagomis. Darbo objektas – šachtinių šulinių vandens kokybės parametrai: nitratai (NO3ˉ ), nitritai (NO2ˉ ), permanganatinė oksidacija (ChDSMn), pH. Darbo tikslas – įvertinti ūkininkavimo įtaką geriamo vandens kokybei ir ryšio tarp sodybos dirbtinių vandens telkinių ir šachtinių šulinių vandens kokybės nustatymas.. Darbo metodai – mokslinės literatūros analizė; cheminės vandens kokybės parametrų kiekybiniai analizės metodai; statistinė analizė, panaudojant EXCEL ir STATISTCA programinius paketus. Darbo rezultatai :atlikus tyrimus nustatyta, kad vanduo užterštas nitratais. Šachtinių šulinių vandens kokybės kitimui būdinga sezoninė tarša. / Subject of research – shallows water quality indicators: nitrate (NO3ֿ), nitrite (NO2ֿ), organic matter (ChDSMn), water pH. Aim of research – to evaluate farming influence of drinking water quality and contact between homestead pond and shallows water quality. Methodology – analysis of scientific literature; chemical water quality analizes methods; statistical analysis using EXCEL, STATISTICA programs. Results of research – the results of scientific research showed, that water is polluted with nitrate. The tendency of water quality variations during seasons was observed.

Research in the use of ozone in water treatment conducted by many authors support the idea that the nature and characteristics of natural organic matter (NOM) present in raw water determines the efficiency of ozonation in water purification. An ozone contact chamber was designed and made to allow pre-ozonation of water to take place. The concentration of ozone in the chamber was determined using the Indigo method. For the duration of one year, water samples were collected from four different sampling sites and analyzed to determine their overall ecological status with regard to several variables such as pH, chlorophyll-a, SAC254, turbidity, DOC, algal species composition and sum of NOM. Two dams sites and two riverine sites were chosen, Hartbeespoort Dam (a hyper-eutrophic impoundment), Boskop Dam (a mesotrophic impoundment), Midvaal Water Company at Orkney and Sedibeng Water at Bothaville. The samples were treated in Jar Tests with FeCI3 and the same variables were measured. Preozonation followed by Jar Tests was performed on each sample at twoconcentrations of ozone and the variables were measured to examine the efficiency of ozonation. In general, the ph was high and stayed the same for all the samples and for all the treatments. DOC was variable and showed no relationship to any other variable or to the treatments. Hartbeespoort Dam was found to be a eutrophic impoundment characterized by high algal bloom of the cyanobacteria Microcystis sp., Turbidity, SAC254, and the sum of NOM were lower than for the riverine sites but higher than for Boskop Dam. The NOM constituted more intermediate molecular weight(1MW)and low molecular weight (LMW) fractions than the riverine sites. Ozone was effective in reducing chlorophyll-a, turbidity and SAC254 from Hartbeespoort Dam, but the presence of large numbers of algal cells interferes with its efficiency. Release of cell-bound organics after ozonation can lead to increases instead of decreases in these variables. Jar Test results demonstrate that ozonation improves water quality when compared to conventional treatment although the interference of algal cells can alter results. Boskop Dam is a mesotrophic impoundment characterised by low productivity, low SAC254, tow turbidity and low sum of NOM. However, it has a large portion of the LMW fraction of NOM present. This LMW fraction affects the treatment process as this fraction is not acted upon by ozone. Therefore it was found that ozonation did not improve the quality of the water when compared to conventional treatment. The two riverine sites, Midvaal and Sedibeng were similar to each other. Both sites had high algal productivity with high chlorophyll-a values indicative of algal blooms observed at certain times. These blooms consisted either of members of Bacillariophyceae or Chlorophyceae. High turbidity and SAC254 was observed during the rainy season and was related to the high percentage HMW and IMW fractions of NOM present. There was correlation between the turbidity and SAC254 of these sites leading to the assumption that the turbidity of the river is due to the presence of HMW humic fractions of NOM. Ozonation was effective in improving water quality with respect to turbidity, SAC254 and chlorophyll-a removal, both on its own and after conventional treatment when combined with a coagulant. However, the species of algae present affects ozonation as members of Bacillariophyceae are not affected by the actions of ozone because of the presence of a silica frustule whereas members of Chlorophyceae are easily removed by ozone. In general, ozone acts upon the HMW and LMW fractions of NOM causing them to breakdown into smaller fractions. Ozone has no effect on samples that have a high percentage of the LMW fraction of NOM. This LMW fraction is more readily removed by conventional treatment than by ozonation. The presence of large numbers of algal cells as well as the species of cells can negatively affect the treatment process with regard to ozone. / Thesis (M. Environmental Science (Water Science))--North-West University, Potchefstroom Campus, 2007.

This research addresses the potential ecotoxicity of two emerging carbonaceous materials: C 60 and biochar. The use of these materials is rapidly increasing, as well as their potential for widespread applications. Thus, information about unintended consequences associated the widespread use, incidental or accidental release, and disposal of these emerging materials is needed. The environmental impacts of C 60 , its stable water suspension (nC 60 ), and biochar are assessed here using bacteria and earthworms as model receptors. The antibacterial activity of nC 60 can be mitigated by the presence of natural organic matter as a soil constituent or dissolved in the water column. Sorption to soil might decrease the bioavailability of nC 60 and thus its toxicity to bacteria. Aqueous organic matter also may mitigate nC 60 toxicity. Pristine C 60 showed toxicity to the earthworm's reproduction and was rapidly bioaccumulated by earthworms, although to a lower extent than smaller phenanthrene molecules that are more hydrophobic; thus, the large molecular size of C 60 hinders its bioaccumulation. Less bioaccumulation occurred at higher C 60 concentration in soil, which is counterintuitive and reflects that higher C 60 concentrations that exceed the soil sorption capacity exist as larger precipitates that are less bioavailable. Earthworms avoided soils amended with high concentrations of dry biochar, and experienced significant weight loss after 28-day exposure. The avoidance response was likely to avert desiccation rather than to avoid potential toxicants (i.e., PAHs formed during biochar production by pyrolysis) or nutrient scarcity. By wetting the biochar to field capacity before exposing the worms, this adverse effect can be completely mitigated. Overall, this research provides a foundation for ecotoxicity assessment associated with exposure to C 60 or biochar, and establishes a method by which other emerging materials can be evaluated for their potential environmental impacts.

Stringent water quality regulations and general aesthetic issues have urged drinking water industry to apply advanced water treatment technologies that can meet multiple treatment objectives. Removal of significant amount of natural organic matter (NOM), including colour causing organics, to meet stringent disinfection by product (DBP) regulations from source water with low alkalinity and low turbidity is very challenging with conventional water treatment processes. Membrane filtration processes are effective in removing significant amount of NOM thus minimizing the formation of carcinogenic DBPs. However, fouling of membrane is a major problem affecting system performance. Improved pretreatment of feed water helps reduce or eliminate membrane fouling. This study characterized source water, examined fouling in nanofiltration (NF) membranes and explored various pretreatment options to reduce NF fouling. Resin fractionation was performed to characterize NOM and to identify the major fractions responsible for DBP formation in natural source water of the Tatamagouche water treatment plant (WTP) in Nova Scotia. The source water primarily comprised of hydrophilic neutrals (HIN) and hydrophobic acid (HOA) compounds, with the latter being a major contributor to the DBP formation. Fouling behaviour of the NF membranes was examined at bench- and full-scale levels to understand the impact of source water quality on membrane fouling in the Tatamagouche and Collins Park WTPs. Bench- and full-scale results revealed higher fouling in the Collins Park WTP which together supported ongoing membrane cleaning practices in the plant. Surface enhanced Raman spectroscopy (SERS), demonstrated here as a novel technique, suggested that carbohydrates and proteins are the main foulants in the source water. Bench-scale experiments conducted to evaluate the performance of ozone (O3), ultraviolet (UV), hydrogen peroxide plus ozone (H2O2/O3), H2O2 plus UV (H2O2/UV) and O3 plus UV (O3/UV) for reducing NOM and DBP precursors suggested that the O3/UV AOP offers the optimum reduction of NOM. Integrating AOP pretreatments with NF membrane resulted in an improved permeate flux but not permeate quality of the NF membrane.

Research has shown biological filtration can be a successful treatment for manganese (Mn) removal from groundwater and surface water. In this study, bench-scale direct biofiltration was used to remove Mn and dissolved organic carbon (DOC) from a pH 6 surface water source in Halifax, Canada. The removal of Mn in pH 6 surface water was significantly (? = 0.05) removed with 200-300 µg/L phosphorus (P), and 500 µg/L hydrogen peroxide (H2O2). DOC removal was significantly (? = 0.05) improved with granular activated carbon (GAC) media, P enhancement at 200-300 µg/L, and H2O2 enhancement at 500 µg/L. Mn was likely removed by biological oxidation and physical adsorption to biogenic Mn and iron (Fe) oxides. These results show direct biofiltration of surface water at pH 6 can remove Mn below the 50 µg/L aesthetic guideline from a Mn loading of over 1 mg/L. Further research is required to verify the microbial mechanism.

Natural organic matter (NOM) is present in all surface waters as a result of decaying vegetation, biological activity, and organic soil. Alternative NOM removal processes such as anion exchange resins (AERs) have shown NOM removals typically ranging between 50 to 90%, with up to 99% removal achieved in some cases. The first portion of this study evaluated the performance of two AERs; a conventional Type 1 AER and magnetic ion exchange resin (i.e. MIEX®) for NOM removal from surface water quantified by UV254, dissolved organic carbon (DOC), and specific UV absorbance (SUVA). Samples were also characterized for chloride, sulphate, and chloride-to-sulphate mass ratio (CSMR) to provide additional information on water quality characteristics of AER treated waters. Overall, the results showed that both AERS were effective for removing NOM. However, the MIEX® resin provided greater removal of NOM with shorter contact times compared to the conventional resin investigated. Water treated with MIEX® resin showed significantly higher chloride and lower sulphate concentrations than the conventional AER. Higher CSMR values were found with MIEX® treated water compared to conventional AER system, although both resins showed CSMR much greater than 0.5, which can increase galvanic corrosion effects with lead. Bench-scale jar tests were conducted to investigate the impact of temperature on the efficacy of three NOM removal treatment technologies; enhanced coagulation with alum, MIEX® and a combined MIEX® treatment followed by coagulation with a low dose of alum. Higher settled water turbidity was observed during cold water operating conditions for all three processes. At cold-water operating conditions, DOC removal was reduced with combined MIEX® -Alum treatment, and UV254 removal was impacted for both MIEX® and MIEX® -Alum processes. The combined MIEX®-Alum process was found to provide the lowest THMFP and HAAFP at both temperatures to concentrations lower than current regulatory maximum acceptable concentration (MAC) guidelines in Canada. Surface charge analysis experiments were performed at bench-scale using synthetic water containing humic acid to determine the relationship between NOM and the charge of AER-treated waters. Further bench and pilot-scale studies were performed to investigate the use of surface charge measurements to monitor and optimize NOM removal during treatment with AER systems. Strong correlations were observed between UV254 and respective charge measurements (i.e. ZP, SC) of AER-treated synthetic and raw waters. The results of this research has shown that it is possible to use charge to optimize the MIEX® process for NOM removal. Additionally, it was found that SC measurements could be used as an operational tool for AER processes, where deviations in SC from optimum treatment would indicate the requirement for fresh resin addition or resin regeneration.

This dissertation investigates harvesting of marine microalgae for bioenergy and production of two recombinant proteins for therapeutic applications in Chlamydomonas reinhardtii. The first study describes harvesting of marine microalgae by flocculation using aluminum chloride (AlCl_3), natural polymer chitosan, and synthetic cationic polymers. Harvesting and concentration process of low concentration microalgae cultures ranging from 1 to 2 g dry weight per liter was affected by algogenic organic matter (AOM), ionic strength, cell concentration, polymer charge density, and media pH. Marine microalgae flocculation was greatly affected by the presence of AOM independently of the flocculant chemistry. Presence of AOM demanded extra flocculant dosage i.e., 3-fold of AlCl3, 7-fold of highly charged synthetic cationic polymer, and 10-fold of chitosan. Flocculant dosage required for > 90 % flocculation efficiency in the presence of AOM was 160 mg/L, 50 mg/L, and 20 mg/L when using AlCl_3, chitosan, and best (more efficient) synthetic polymer respectively. The high-ionic strength of saline water did not have a significant effect on flocculation efficiency when using AlCl_3. However, to achieve efficient algal biomass removal, application of highly-charged synthetic polymers was required to overcome the presence of electrolytes. The best synthetic cationic polymer tested herein, which achieved greater than 90 % flocculation efficiency at 20 mg/L dosage, was a polymer with 99 % cationic charge density. Cell concentration also affected flocculant dosage requirement; low density cultures (10^6 cells/mL) required 6-fold greater dosages than cultures grown until early stationary phase (10^7 cells/mL). The second study addresses cultivation, extraction and purification challenges of two complex recombinant proteins, an immunotoxin molecule (MT51) and malaria vaccine antigen (Pfs25) produced in the chloroplast of C. reinhardtii. Main challenges identified were i) low transgene expression level, ii) proteolytic instability of MT51 immunotoxin, and iii) aggregation of Pfs25 antigen. Optimal expression and accumulation of Pfs25 antigen required growing C. reinhardtii cultures to late exponential phase (10^6 cells/mL) and inducing transgene expression for 24 h at a photon irradiance of 120 µmol/m^2s.