Methods of chemical hazard ranking and toxic impact assessment estimate fate and toxicity assuming the chemical exists in dissolved and particulate phases and, for metals, that all dissolved species are equally bioavailable. This treatment of metals, similar to organic chemicals, introduced a significant error in their estimates of hazard ranking since metal bioavailability and ecotoxicity are related to truly dissolved phase and specifically free metal ion within it. My thesis addressed this concern by developing a new method that introduced Bioavailability Factor (BF) to the calculation of Comparative Toxicity Potentials (CTPs) for hazard ranking of chemicals; also known as Characterization Factors for use in Life Cycle Impact Assessment (LCIA). First, the metal speciation/complexation was incorporated into fate calculations by loosely coupling commercial geochemical metal speciation model, WHAM, with a multimedia fate model, USEtoxTM, which is originally designed to calculate CTPs for organic chemicals. Second, Biotic Ligand Model (BLM) was used to calculate the bioavailability-corrected adverse toxic effects of metals. This new method was applied to assess the implications of choosing environmental characteristics, notably freshwater chemistry, by calculating BFs and CTPs of several cationic metals (e.g., Cd, Cu, Co, Pb, Ni and Zn) using 12 European, 24 Canadian ecoregions, several distinct freshwater-types selected from large river and lake systems world-wide. The newly estimated metal CTPs (i.e., ecotoxicity potentials) are up to ~1000 times lower than previous values used in LCIA. Notably the model results showed that the absolute values of CTPs, and their relative ranking amongst chemicals, are a product of the characteristics of a receiving environment. Hence it is crucial to select a generic freshwater archetype on which this analysis should be based. Finally, the new model framework was extended to apply within the Unit World Model (UWM) framework to estimate critical loads (CLs) of cationic metals to surface aquatic systems.

Master of Science / Department of Biological & Agricultural Engineering / Philip L. Barnes / Wichita, Kansas water supply is derived from multiple sources. Unfortunately, these sources are not expected to meet the future needs of the population. This predicted water shortage led to the development of the Equus Beds Recharge Project, to investigate artificial recharge as a solution to meet future water demands. This project focuses on the Little Arkansas River as a source of this recharge water. The Kansas Department of Health and Environment set a daily 3[Mu]g/L standard for the recharged water as opposed to surface waters used directly for drinking water which can't exceed a yearly average atrazine concentration of 3[Mu]g/L. During 2005, five sub-watersheds within the Little Arkansas River watershed were instrumented to collect water quality samples and measure flow rate to calculate daily contaminant loadings. Three of the sub-watersheds used atrazine best management practices (BMPs) applied to grain sorghum while the remaining two sub-watersheds maintained existing farm practices. During 2007, monitoring continued and additional atrazine BMPs were applied to corn grown in the treated sub-watersheds. During both 2006 and 2007, water quality monitoring was used to examine water quality parameters throughout the entire watershed. Watershed-scale monitoring allowed for pollutant transport patterns to emerge both spatially and temporally and indicated potential sources of the pollutants. In this particular study, atrazine and sediment loss were the two most important water quality parameters. Results from this study showed that by using BMPs the concentration of atrazine was decreased by greater than 40% in 2006 when compared to the atrazine concentration from those areas without BMPs. A 5% reduction was seen in 2007, which was due to differences in precipitation and runoff between the two years. There was no reduction in sediment losses between the treated and untreated watersheds during 2006, leading to the conclusion that additional practices would be needed to reduce sediment losses as well as any pollutants associated with sediment loss (ex nutrients absorbed to the sediments). During 2007, sediment, nitrogen, and phosphorus were 66%, 60%, and 55% lower respectively in the treated versus untreated sub-watershed. These 2007 differences were related to rainfall pattern differences in the sub-watersheds.

Master of Science / Department of Geology / Saugata Datta / More than 75 million people in the Bengal Delta of eastern India and Bangladesh are exposed to drinking water with dangerously high arsenic (As) concentrations; the worst case of environmental poisoning in human history. Despite recognition of dangers posed to chronic exposure to drinking water with elevated As, its biogeochemical cycle is inadequately constrained in groundwater flow systems due to its complex redox chemistry and microbially-mediated transformations. Arsenic concentrations in Bengal Delta sediments are comparable to global averages, but its highly heterogeneous spatial distribution (on scales of meters to kilometers) in sediments and groundwaters is poorly understood. Though many research efforts have targeted understanding this heterogeneity in Bangladesh, less work has been done in eastern India. Murshidabad (23°56.355‘N, 88°16.156‘E), an eastern district in West Bengal, India, where groundwaters are highly As-affected (~4000 μg/l), was chosen as our study area. Research objectives were: (1) characterize sediment cores (mineralogically, geochemically) and groundwaters (hydrochemically, isotopically) in areas with contrasting As concentrations—west (low-As) and east (high-As) of river Bhagirathi, a major distributary of Ganges flowing through the heart of Murshidabad; (2) describe and understand the extent of spatial variability, laterally and vertically, of dissolved As concentrations in shallow (< 60 m) aquifers, comparing sediment core chemistry to water chemistry; (3) identify source(s) of aquifer recharge and (4) role(s) of inorganic carbon within the aquifer to understand the bioavailability and mobilization of As from sediments to groundwaters. Mineralogical differences between high-As (grey) and low-As (orange-brown) sediments, were the presence of greater amounts of micas, Fe- and Mg-rich clays, amphiboles, carbonates, and apatite in high-As sediments; these were virtually absent from low-As sediments. In high-As areas, As was associated with amorphous and poorly-crystalline Fe-oxyhydroxide phases and labile (specifically-sorbed) phases, especially where Fe(II):Fe[subscript]T was high in the sediments. High-As groundwaters had high As(III):As[subscript]T, iron, bicarbonate, phosphate, and ammonium, and low concentrations of chloride and sulfate. Dry season precipitation was probably the main source of aquifer recharge; lighter values of [superscript]13C in dissolved inorganic carbon resulted from oxidation of natural organic matter. This study points to an idea that both microbially-mediated oxidation-reduction and competitive ion-exchange processes occurring in shallow aquifers of Murshidabad drive As mobilization and sequestration by aquifer sediments.

Master of Arts / Department of Geography / Douglas G. Goodin / My thesis characterizes the temporal and spatial behavior of ozone and fine particulate matter in the Kansas City metropolitan area. I also investigate the capability of a synoptic weather typing scheme, the Spatial Synoptic Classification, to characterize and explain the behavior of ozone and fine particulate matter in the Kansas City area. Daily maximum ozone concentrations from nine active ozone monitoring stations and daily average particulate concentrations six active PM2.5 monitoring stations were compared to daily SSC weather type records from 2004-2010. Analysis of Variance (ANOVA) tests were conducted on the ozone and PM2.5 data to analyze temporal and spatial behavior. A non-parametric recursive partitioning technique was used to create a conditional inference tree-based regression model to analyze the association between the different SSC weather types and the selected pollutants. The ANOVA results showed significant seasonal trends with both pollutants. In general, ozone concentrations are typically lower in the spring and autumn months and higher during the summer months. PM2.5 concentrations were not as dependent on the season, however, they did tend to be higher in the late summer months and lower in the autumn months. The results also showed significant differences for both pollutants in average concentration depending on location. The ozone concentrations generally tended to be higher in the areas that are located downwind of Kansas City and lowest at the station located in the middle of the urban area. Fine particulates also seemed to be highest in the downwind portion of the urban area and lowest in the region upwind of the city. The conditional inference tree showed that higher concentrations of both pollutants are associated with tropical air masses and lower concentrations are associated with polar air masses.

Doctor of Philosophy / Department of Agronomy / Ganga M. Hettiarachchi / Urban gardens have been a popular re-use option in the transformation of brownfields—located in older industrialized cities and near peri-urban developments. They provide accessible, available, and affordable supplies of fresh fruits and vegetables, effectively reducing the enigma of “food deserts” across U.S. cities. However, direct (soil ingestion, inhalation) and indirect (soil-plant-human) human exposure concerns about real or perceived trace element contamination in urban soils persist due to previous use. Elevated lead (Pb) and/or arsenic (As) concentrations were found at two (Tacoma and Seattle, WA) urban gardens. The Tacoma site was contaminated with Pb (51 to 312 mg kg-1) and As (39 to 146 mg kg-1), whereas soil Pb at the Seattle site ranged from 506 to 2,022 mg kg-1, and As concentrations were < 20 mg kg-1. Experimental design at both sites was a randomized complete block with a split-plot arrangement (main plots: biosolids/compost vs. non-amended control; sub-plot: plant type). Tacoma site treatment included a Class A biosolids mix (TAGRO) with dolomite. The Seattle site was amended with Cedar-Grove Compost (CGC) plus dolomite. Efficacy of biosolids/compost amendment in reducing Pb and As concentrations was evaluated using root, leafy, and fruit vegetables. Soil Pb and As bioaccessibility were also evaluated. Food chain transfer of Pb and As in vegetables due to surface contamination of produce samples were evaluated on the basis of cleaning procedures. A laboratory incubation study and a controlled greenhouse experiment were conducted on soils collected from the Tacoma site. Effectiveness of addition of laboratory synthesized ferrihydrite (Fh: iron oxyhydroxide) and TAGRO mix, each alone or in combination were screened and tested on the Pb and As co-contaminated Tacoma soil. Extended X-ray Absorption Fine Structure (EXAFS) spectroscopy studies of Pb and As were conducted on incubation study samples to understand treatment-induced Pb- and As-speciation changes. Dilution of soil Pb (10 to 23%) and As (12 to 25%) were observed for biosolids amendment at the Tacoma site, while CGC amendment resulted in 20 to 50% dilution in soil Pb at the Seattle site. Biosolids and CGC amendments reduced Pb concentrations in the vegetables by 50% to 71%. At both sites, Pb concentrations of root vegetables exceeded the MLs established by the Food and Agriculture Organization (FAO) and the World Health Organization (WHO). Arsenic concentrations in vegetables were below an estimated ML and were reduced by 46% to 80% when grown on biosolids amended soils. Laboratory cleaning further reduced Pb and As food-chain transfer in vegetables grown in contaminated urban soils. Laboratory incubation and greenhouse studies showed dissolution of Pb in TAGRO plus Fh, and Pb concentrations in Fh amendments were significantly lower than the other amendments. Bioaccessible Pb and As were low. Significant reductions in bioaccessible As were observed when soils were amended with both TAGRO and Fh. X-ray absorption spectroscopy results indicated that chloropyromorphite-like (stable Pb phosphates) phases were the most dominant Pb species. Arsenic existed mainly as As5+, scorodite (FeAsO4•2H2O)-like species in all the treatments ranging from about 60% (control) to about 70% (TAGRO plus ferrihydrite). Amendments utilizing both biosolids and Fh significantly reduce human exposure risks present in urban soils contaminated with Pb and As.

Master of Science / Division of Biology / Martha E. Mather / In contrast to well documented adverse impacts of large dams, little is known about how smaller low-head dams affect fish biodiversity. Over 2,000,000 low-head dams fragment United States streams and rivers and can alter biodiversity. The spatial impacts of low-head dams on geomorphology and ecology are largely untested despite how numerous they are. A select review of how intact low-head dams affect fish species identified four methodological inconsistencies that impede our ability to generalize about the ecological impacts of low-head dams on fish biodiversity. We tested the effect of low-head dams on fish biodiversity (1) upstream vs. downstream at dams and (2) downstream of dammed vs. undammed sites. Fish assemblages for both approaches were evaluated using three summary metrics and habitat guilds based on species occurrence in pools, riffles, and runs. Downstream of dams vs. undammed sites, we tested if (a) spatial extent of dam disturbance, (b) reference site choice, and (c) site variability altered fish biodiversity at dams. Based on information from geomorphic literature, we quantified the spatial extent of low-head dam impacts using width, depth, and substrate. Sites up- and downstream of dams had different fish assemblages regardless of the measure of fish biodiversity. Richness, abundance and Shannon’s index were significantly lower upstream compared to downstream of dams. In addition, only three of seven habitat guilds were present upstream of dams. Methodological decisions about spatial extent, and reference choice affected observed fish assemblage responses between dammed and undammed sites. For example, species richness was significantly different when comparing transects within the spatial extent of dam impact but not when transects outside the dam footprint were included. Site variability did not significantly influence fish response. These small but ubiquitous disturbances may have large ecological impacts because of their potential cumulative effects. Therefore, low-head dams need to be examined using a contextual riverscape approach. How low-head dam studies are designed has important ecological insights for scientific generalizations and methodological consequences for interpretations about low-head dam effects. My research provides a template on which to build this approach that will benefit both ecology and conservation.

Master of Science / Department of Agronomy / Charles W. Rice / Biotic interactions among mycorrhizal fungi, nematodes, plants and other microbial communities can have significant effects on the dynamics of C and nutrient cycling. The specific objectives of this study were (1) to evaluate the effects of grazing and mycorrhizal symbiosis on the allocation and storage of C, especially for plant above-and belowground biomass, (2) evaluate the biotic rhizosphere interactions and their role in C cycling, (3) determine the soil microbial community structure as a result of the plant-mycorrhizal symbiosis, and (4) determine the effect of mycorrhizal fungal abundance on soil aggregation. The soil for the experiment was sampled from the Ap horizon of a fine-silty, mixed, superactive, mesic Cumulic Hapludolls located at Konza Prairie Biological Station, Manhattan KS. The experiment was a three-way factorial in a complete randomized block design with four replications. The three factors were mycorrhizae (M), nematodes (N), and phosphorus (P). In a greenhouse study, 96 microcosms (52×32×40cm) were planted to Andropogon gerardii Vit. so that a third of the microcosms could be destructively sampled at the end of each growing season for three years. Plant biomass was separated into aboveground, rhizomes, and roots. All components were dried and weighed at harvest. Mycorrhizal fungi and P increased plant aboveground biomass, while nematodes decreased plant aboveground biomass compared to non-inoculated controls. As expected, P increased plant root biomass, while mycorrhizae increased plant rhizome biomass. Nematodes decreased both above- and belowground biomass. Phospholipid and neutral lipid fatty acid (PLFA and NLFA) analysis were determined for both soil and roots. Water-stable aggregates were separated using a modified Yoder wet-sieving apparatus and analyzed for mass, total C and N, and the isotopic composition of C. There was a positive relationship between AM fungal abundance in the soil and the mass of the largest macroaggregates (>2000µm) after the 3rd year (r=0.67). The effect of roots on the macroaggregate (>2000µm) fraction was not apparent. Phosphorus significantly increased smaller macroaggregates (250-2000µm), along with significantly enhanced plant root biomass, which indirectly demonstrated the effect of roots on the formation of macroaggregates (250-2000µm). The addition of P induced more plant derived C into the aggregates than the non-P amended microcosms as suggested by the [superscript]13C content of the aggregates. Our results confirmed the importance of biotic and abiotic interactions among mycorrhizae, nematodes, and phosphorus on plant growth and the resulting effect on the soil C cycle and soil aggregation.

Master of Arts / Department of Landscape Architecture/Regional and Community Planning / Lee R. Skabelund / This report presents one approach for increasing understanding, appreciation and protection of watersheds by individuals living within the urban-to-rural lands interface. The purpose of the study is to provide guidance to developing and implementing a driving tour of environmentally sensitive land around Clinton Lake and the Upper Wakarusa Watershed (UWW). Although the tour is particular to the UWW, the principles will be useful to planners and watershed advocates working to promote water quality improvement in other geographic areas. A first step in increasing community involvement to restore and protect watersheds is developing a broader public understanding of what watersheds are and their integral part in daily life. By taking a driving tour (literally or virtually), participants can see firsthand how a watershed functions and the values it provides to people and ecosystems. Two key ingredients in the planning process are public participation and clearly defined goals. Public participation begins with awareness of an issue that impacts lives. The first step in engaging the public is to develop a framework for making residents aware that watersheds are a critical part of their environment and the health of their community. The driving tour of the Upper Wakarusa Watershed should help residents and visitors experience a “sense of place” related to the watershed by achieving three over-arching goals: Develop meaningful themes that engage the residents and visitors in learning about watersheds and give insight to their relationships with the watershed. Introduce concepts that are relevant to the lives of residents and visitors and their understanding of a watershed. Generate a stronger “sense of place” as it relates to the Upper Wakarusa watershed. The driving tour in this report has been designed to serve as a broad blueprint for future implementation. The route was devised to take advantage of area resources, especially those on public land, while adhering to guidelines proven successful in promoting rural areas such as the Flint Hills and Cheyenne Bottoms. The actual implementation of the Upper Wakarusa Watershed Driving Tour is expected to be led by local coalitions, and the precise route should be adjusted as necessary.

I studied how geology, land use and rainfall, correlated with peak flow responses in 110 headwater stream sites during a drought year. Highest discharges were observed in the most developed catchments and in the most poorly drained soils, but specific responses were variable depending on both geology and land disturbance. Redundancy analysis indicated that both surficial geology and land disturbance were important predictors of discharge and that rainfall was in general a poor predictor of discharge. I conclude that responses of headwater streams to individual storms are unpredictable from data generated using GIS, but increased peak flows occur associated with human development, mitigated by surficial geology. The headwater streams that are most vulnerable to flow alterations occur on poorly drained soils, and where urbanization tends to concentrate. Much greater attention to managing water is required if further degradation of stream ecosystems is to be prevented from our future land use.

Master of Science / Department of Agronomy / Nathan O. Nelson / Phosphorus (P), an essential nutrient for plant growth and animal needs, has been identified as an ubiquitous water quality impairment in the United States. In Kansas, a major agricultural state, P loading to the surface waters is a top priority because of the critical role of P enrichment in eutrophication processes and resultant water quality degradation. The objective of this study was to quantify the P sorption and desorption of both stream sediments and upland soils in two Kansas watersheds with contrasting degrees of animal agriculture; Upper West Emma Creek (UWEC) and Red Rock Creek (RRC) watersheds. In-stream sediments were collected from banks, pools, riffles and depositional features. Soils were sampled from wheat, row crop, pasture, and manure-amended fields. Stream water samples were taken under baseflow and storm flow conditions. Our analyses of sediments and soils included equilibrium P concentration at zero net P sorption (EPC[subscript]0), maximum adsorption capacity (P[subscript]max), anion exchange extractable P (P[subscript]lab) and degree of P saturation (DPS). Water samples were analyzed for dissolved reactive phosphorous (DRP). Bank erosion pins were installed in order to estimate bank erosion rates in both watersheds. Results showed that in-stream sediments do not have much more sorption capacity remaining indicated by low P[subscript]max and high DPS. A comparison between mean P[subscript]lab of stream sediments (8.8 mg P kg[superscript]-1 soil) versus field soils (61.2 mg P kg[superscript]-1 soil) reflected that they represent a relatively minor long-term P supply. Of the stream sediments, bank soils had the highest Plab concentrations (24.8 mg P kg[superscript]-1 soil) and would be the largest in-stream P source. Manure-amended fields had the highest Plab (118.6 mg P kg[superscript]-1 soil) due to continued inputs of manure-based P; therefore, representing a large available P pool. Bank erosion contributed about 41% and 11% of the total sediment load in UWEC and RRC respectively. Sediments loads indicated that RRC has more upland sediment inputs than UWEC. Moreover, DRP during storm flow was higher at RRC than UWEC, indicating higher P inputs in RRC from upland soils. Finally, in order to minimize P inputs to the stream system, bank stabilization should be addressed in UWEC and upland best management practices should be implemented in RRC.