Laboratory single-species toxicity tests are used to assess the effects of contaminants on aquatic biota. Questions remain as to how accurately these controlled toxicity tests predict sitespecific bioavailability and effects of metals. Concurrent 42-day Hyalella azteca exposures were performed with cadmium and final treated municipal effluent in the laboratory and at the University of North Texas Stream Research Facility. Further laboratory testing in reconstituted hard water was also conducted. Endpoints evaluated include survival, growth, reproduction, and Cd body burden. My results demonstrate that laboratory toxicity tests may overestimate toxicity responses to cadmium when compared to effluent dominated stream exposures. Discrepancies between endpoints in the three tests likely resulted from increased food sources and decreased cadmium bioavailability in stream mesocosms

Heavy metal bioaccumulation in aquatic organisms may occur through direct or indirect uptake routes. Research indicates that the significance of uptake route varies with contaminant and organism exposed. The relative importance of different metal sources in aquatic systems was investigated by exposing freshwater snails to dietary or dissolved sources of cadmium. Snails were exposed to control, contaminated food only, contaminated water only, and contaminated food and water treatments. During the 15-day exposure, samples were taken to determine Cd concentration in snail soft tissue, snail shell, algal food, and overlying water. Analyses of snail soft tissue and shells indicate that exposure route significantly affects Cd concentrations in the tissues. In both cases, dissolved Cd is the primary contributor to metal body burden.

In recent years, new classes of aquatic pollutants have received growing concerns from the environmentalists due to their unclear effects and increasing release into the water environment. Generally, before entering the aquatic ecosystem, many of these emerging contaminants are deemed safe active ingredients in the commercial products. This may lead to the underestimation of their potential impacts to the environment, once these substances were drained into the natural waters. So far, a wide range of emerging contaminants are still not well studied. In this thesis work, the environmental behaviors for two typical groups of emerging contaminants, which are frequently used in personal care products, are systematically probed in the aquatic ecosystem. One is the hydrophilic compounds - artificial sweeteners and the other one is the moderate hydrophobic compounds - ultraviolet (UV) filters. Acesulfame and sucralose are two of the most commonly used artificial sweeteners, which are a newly recognized class of emerging contaminants due to their widespread occurrence and extreme persistence in water environment. To date, however, their environmental behaviors, fates as well as long term ecotoxicological contributions in our water resources still remain largely unknown. In this work, a photodegradation investigation with UV/TiO2 was performed on these two artificial sweeteners, which projected their potential impacts under prolonged exposure to intensive solar irradiation. Real-time observation of the degradation profiles in both sweeteners illustrated that formation of new photo by-products under prolonged UV irradiation is highly viable. For the first time, acute toxicity for the degradates of these two sweeteners were measured and the enhancement in their ecotoxicity has been observed during the irradiation. In an attempt to neutralize this prolonged environmental threat, the feasibility of UV/TiO2 as an effective mineralization process in wastewater treatment was evaluated for both sweeteners. As a result, relatively higher removal efficiencies for acesulfame and sucralose were achieved in this study. For UV filters, a comprehensive investigation on their environmental behaviors and impacts was described in this thesis, covering the occurrence study in surface water and biota, environmental fate and their ecological risks. In the first step, an analytical method based on ultra performance liquid chromatography-tandem mass spectrometry (UPLC-MS/MS) was developed for the simultaneous determination of twelve UV filters in the environmental waters, which achieved good sensitivity to sub-ng/L levels. To monitoring their occurrence in local marine environment, the regional distribution of these sunscreen compounds was monitored along the coastline of Hong Kong. At the same time, considering the intensive consumption of sunscreen products in hot weathers, seasonal variation of UV filters between summer and winter was taken into consideration in our occurrence study. Additionally, we also monitored their occurrence in the drinking water supply system of Hong Kong, including the source water in Dongjiang, raw water in local reservoirs and tap water collected from urban communities, to support a good management on the reliable water supply. Furthermore, the distribution results indicated that the incomplete removal of UV filters in the effluents could be a major source for their release into the environmental waters. Aiming to achieve the complete removal of such compounds, a powerful technique of ozonation was employed in this study and the preliminary operational conditions were further provided. Secondly, in order to gain a better understanding of their environmental fate in surface water, a simulative catalytic photodegradation study with UV/TiO2 were performed to investigate the photostability, phototoxicity and the transformation pathways of seven selected UV filters. During the photodegradation, several transformation products were primarily identified. Thirdly, since lipophilic sunscreens were easily accumulated in the biota, we also made efforts to monitor their occurrence in marine organisms of different species, including farmed fish, wild mussels, prawns and sea urchin, which were collected from local offshore areas. Last but not the least, according to the measured concentrations of UV filters in Hong Kong marine environment, we further performed the ecological risk assessment with the approach specific to the marine aquatic compartment, so as to provide the overall understanding on the environmental impacts of these UV filters.

This study analyzed the acute effect of water consumption on resting metabolic rate (RMR). It was hypothesized that water would have a small, nonclinically significant effect on RMR. Men and women ages 18–40 years participated in a crossover study in which each participant received a No Water and Water condition (order determined randomly) with a 7-day washout period between each condition. Both conditions began with visual analog scales to gauge hunger and thirst levels, urine spectrometry to quantify hydration status, and height and weight measurements. The No Water condition consisted of a 30-minute rest period followed by 45 minutes of RMR testing. The Water condition was identical except for the administration of 500 ml of purified water at 3 °C 10 minutes prior to the beginning of the RMR measurement. Resting metabolic rate testing was done via indirect calorimetry. There was not a condition-by-time difference in 24-hour resting energy expenditure, oxygen consumption, or metabolic equivalents when including all data points and controlling for nonlinearity (ps > 0.0682). There was a significant difference in respiratory quotient (RQ) (F = 13.73; p = 0.0006) with the No Water condition showing a slightly higher RQ than the Water condition. The nonlinear pattern was primarily driven by the first several minutes of testing. Accordingly, we completed analyses without the first 5 minutes of data. The results persisted; that is, there was no condition-by-time effect in 24-hour resting energy expenditure, oxygen consumption, or metabolic equivalents (ps > 0.2435). Further, the RQ remained significantly different (F = 10.57; ps > 0.0023); however, it was slightly higher in the Water condition. This study did not support our hypothesis that consumption of 500 ml of water would have a measurable effect on RMR and fuel utilization compared to not consuming water. Rather, this study replicates other studies that suggest there is not an acute measurable effect of water consumption on RMR. Nevertheless, one positive application of these findings is that water may be a suitable control in RMR studies. In addition, these results should not discourage overall water consumption for healthy functioning. Further, consumption of water-rich foods over time could be an effective strategy for weight management (as shown in other studies). Future studies could attempt to determine if larger volumes of water or different temperatures of water have an effect on RMR.

Caffeine, a biologically active drug with many known molecular targets, is recognized as a contaminant of aquatic systems including marine systems. Although the concentrations of caffeine reported from aquatic systems are low (ng/L to μ/L), harmful ecological effects not detected by traditional toxicity tests could occur as a result of caffeine contamination. The goals of this thesis project were to: 1) quantify concentrations of caffeine occurring in the coastal ocean off of the Oregon Coast and to determine if higher levels were correlated with proximity to caffeine pollution sources; and 2) investigate the sub-lethal cellular toxicity of environmentally relevant concentrations of caffeine on Mytilus californianus, an intertidal mussel that is one of the dominant species of the Oregon Coast. Caffeine was analyzed at 14 locations in the coastal ocean off of the Oregon Coast. Sampling locations were stratified between populated areas identified as having sources of caffeine pollution and sites located in sparsely populated areas not in proximity to major caffeine pollution sources. Caffeine concentrations were also measured in the major water body discharging near sampling locations. Caffeine was detected in water from the coastal ocean off of the Oregon Coast at concentrations ranging from below the reporting limit to 44.7 ng/L. The occurrence and concentrations of caffeine in the coastal ocean did not correspond well with pollution threats from population density and point and non-point sources, but did correspond with a storm event occurrence. Caffeine concentrations in rivers and estuaries draining to the coast ranged from below the reporting limit to 152.2 ng/L. Hsp70, a molecular biomarker of cellular stress, was used to investigate the sub-lethal toxicity of environmentally relevant concentrations of caffeine to the mussel M. californianus. Hsp70 concentrations in the gill and mantle tissue of mussels exposed to 0.05, 0.2, and 0.5 μ/L of caffeine for 10, 20, and 30 days were compared to basal levels in control mussels. Hsp70 in the gill tissue of M. californianus had an initial attenuation of the stress protein followed by a significant albeit moderate up-regulation relative to controls in all but the 0.5 μ/L treatment. Hsp70 in the mantle tissue of mussels exposed to caffeine did not differ from control mussels. This Study confirms the presence of caffeine in Oregon's coastal ocean and provides laboratory evidence that environmentally relevant concentrations of caffeine can exert an effect on M. californianus gill tissue at the molecular-level.

Turbidity is an important measurement of water quality, considering it describes water clarity and is an indirect indicator of light transmittance in the water column. Turbidity may impact fish that rely on vision to forage by affecting ability to search for prey. Largemouth bass (LMB; Micropterus salmoides) is a visual predator that may have lower foraging success resulting in reduced growth, reproduction, or survival under conditions of high turbidity. I conducted a field experiment in Wolf Lake, Mississippi to assess impacts of turbidity on diet and distribution and a laboratory experiment with manipulated turbidity levels (0 – 250 NTU) to assess foraging efficiency of LMB. There were no significant relationships between turbidity and diet or distribution in the field study. However, there were significant effects of turbidity on foraging efficiency in laboratory trials. These results indicate that assessing turbidity is important to manage LMB in systems susceptible to high turbidity levels.

No description available.

Studies were conducted with the Asiatic clam, Corbicula fluminea, that examined seasonal periodicities in spawning, body condition, and percent tissue water content. In addition, responses of adults to brief (24 hr) and extended (30 d) periods of exposure to toxicants were investigated. These studies addressed the valve closure behavioral response by adults exposed to chlorine, cadmium, and zinc; the effects of these pollutants and temperature on the levels of metal binding protein in adults; and the efficacy of halogens ( chlorine and bromine) in providing acceptable levels of Asiatic clam biofouling control. Spawning periodicity of C. fluminea was monitored weekly for 8 months in 1984. Observations revealed that spawning occurred on three distinct occasions with peaks in release of veligers in June, August, and October. Percent tissue water content and body condition were monitored monthly in 1985. Significant differences in these parameters were observed among certain months and among size classes. Tissue water content and body condition in the largest individuals were inversely related. Periods of activity (valves parted) and quiescence (valves closed) were determined in the absence and presence of toxicants by continuously monitoring valve movement patterns. Data indicate that the duration of activity periods and toxicant exposure concentration are inversely related. Application of these observations to efforts to control Asiatic clam fouling in industrial water lines resulted in a reduction in the total levels of molluscicide required. Exposure of clams to low levels of chlorine (0. 25 mg/L total residual chlorine) induced valve closure that resulted in weakened clams after two weeks that were more susceptible to increased levels of chlorine. The levels of a metallothionein-like metal binding protein (MBP) in tissues of Q. fluminea following exposure to metal and non-metal stressors were also assessed. In general, exposure to dissolved cadmium resulted in significantly greater levels of MBP than either dissolved zinc, chlorine, or temperature extremes (4°, 30°C). Analysis of individual organ groups demonstrated an inverse relationship between sites of MBP synthesis ( gills, mantle, and adductor muscles versus visceral mass) and mode of exposure to cadmium (dissolved versus food associated). / Ph. D.

Functional and pathological responses of larval, juvenile, and adult Asiatic clams (Corbicula sp.), juvenile and adult fathead minnows (Pimephales promelas), and egg, larval and juvenile Japanese Medaka (Oryzias latipes) to chrysotile asbestos were investigated in 96-hour to 91-day tests. Chrysotile significantly reduced siphoning activity and shell growth of adult clams and siphoning, shell growth, and weight gain of juveniles at 10⁵ fibers/liter during 30-day tests. Larval Corbicula suffered significantly greater mortality and lower release by brooding adults at 10²-10⁸ fibers/liter. Adult and juvenile Corbicula exposed to 10⁸ fibers/liter for 30 days exhibited deteriorated gill tissue and significantly greater tissue water content. Corbicula accumulated up to 1000 fibers/mg in visceral tissue at 10⁸ fibers/liter. Clams collected from the California Aqueduct System exposed to 10⁹ fibers/liter accumulated up to 10⁵ fibers/mg in viscera. Corbicula can be used as a monitor for chrysotile contamination due to its ability to concentrate fibers. Adult and juvenile fathead minnows did not suffer acute toxicity at 10¹² fibers/liter and differential mortality relative to controls up to 10⁸ fibers/liter for 30 days. At the conclusion of the 30-day tests the length, weight, and swimming performance of adult minnows exposed to asbestos were not significantly affected relative to controls. Juvenile minnows exposed to 10⁶-10⁸ fibers/liter had significantly lower weight. Fish exposed to 10⁸ fibers/liter for 30 days accumulated up to 390 fibers/mg in kidney tissue. Egg and larval Medaka were exposed to 0-10¹⁰ fibers/liter of chrysotile until hatching and for thirteen weeks, respectively. Eggs responded erratically to asbestos exposure and no conclusive trends could be drawn. Larval Medaka exposed to 10⁶-10¹⁰ fibers/liter had reduced growth by 14 days. Fish exposed to 10¹⁰ fibers/liter suffered 100% mortality by 60 days. Fish exposed to asbestos developed epidermal tumors, thickened epidermal tissue, increased mucous cell density in the intestinal tract, constricted kidney tubules, and abnormal levels of lipid and endoplasmic reticulum in the liver. Maximum asbestos uptake occurred in fish exposed to 10⁸ fibers/liter for 91 days (400 fibers/mg). The extent of damage to fish and clams at levels greater than 10⁴ fibers/liter in the laboratory suggests that aquatically transmitted asbestos is a potential hazard to these species in the field. / Ph. D.

A site-specific artificial stream system receiving selected levels of fly ash, heavy metals, or sulfates was compared to a natural stream (Adair Run) influenced by effluent from the fly ash settling basin at Glen Lyn, Virginia. Aufwuchs communities colonizing glass microscope slides were monitored for dry weights, ash-free dry weights, chlorophylls, ATP, and 14-carbon and 35-sulfate assimilation rates. Productivity appeared to be enhanced in Adair Run due to increased concentrations of sulfates (150 mg/l), and temperature (delta T=4. 5 C) in the ash basin effluent. A recovery response was observed following termination of basin operation. Artificial streams receiving selected concentrations of fly ash at low TSS (8.0-25 mg/l) exhibited no inhibition for all parameters except chlorophyll a and ATP. Higher levels (80-100 mg/l) depressed all aufwuchs parameters except AFDW within six days. Six heavy metals (Cd, Cr, Cu, Ni, Pb, Zn), when collectively pumped into artificial streams at concentrations modeling the ash basin effluent effectively lowered productivity parameters. This was followed by a slow recovery response. Aufwuchs demonstrated an ability to bioconcentrate heavy metals from ambient water. Streams dosed with sulfates demonstrated a stimulation response at concentrations modeling the Adair Run system. Current U.S. EPA effluent guidelines for fly ash (30 mg/l maximum weekly average; 100 mg/l maximum) are evaluated concerning the degree of protection afforded primary producers of aquatic receiving systems. / Master of Science