The objective of this study was to evaluate the impact of extreme acidic and alkaline pH excursions of fish populations in streams receiving fly ash settling basin effluent. Fish communities were sampled above and below the effluent outfall in a mountain stream, Adair Run, adjacent to the coal-fired Glen Lyn Power Plant in southwestern Virginia. This effluent, which exhibited a pH increase of up to pH 9.3 as the basin nearly filled, contributed to a downstream decline in species diversity and an increased dominance of the stoneroller (Campostoma anomalum), which displaced more sensitive species. Laboratory avoidance studies, utilizing a steep-gradient trough apparatus, were used to investigate the potential role of avoidance behavior that may alter fish distributions in acidic and alkaline waters. Stonerollers, rainbow trout (Salmo gairdneri), golden shiners (Notemigonus crysoleucas) and spotfin shiners (Notropis spilopterus) exhibited first significant avoidance responses to continuously decreasing pH conditions at pH 6.0-7.0, well above the 96-hr LC50 values of 4.05 and 4.24 for trout and golden shiners, respectively. When the pH was gradually increased, avoidance thresholds of pH 9.5- 11.0 were observed, beyond the 96-hr LC50 values of 9.13 and 8.86 for trout and golden shiners. Single acute alkaline exposures initially yielded more rapid avoidance responses, with acclimation to alkaline conditions frequently occurring within 30 minutes. Gill histological alterations, as observed by transmission electron microscopy, were detected following exposure to extreme pH excursions, with more rapid changes occurring with alkaline exposures. Gill tissue showed marked recovery within 8-14 days. / Master of Science

M.S.

The effects of sublethal copper on metabolism were in vestigated in bluegill (Lepomis macrochirus) by measuring whole body oxygen consumption in fish exposed to sublethal copper alone and in conjunction with a temperature increase. In vitro oxygen consumptions of liver, brain, and gill were also measured under these two conditions, as was the accumulation of copper in these tissues. In addition, the concentration of copper in bile was measured. Copper was found to decrease whole body oxygen consumption in animals exposed to copper alone, although the oxygen consumptions of tissues were not significantly altered. This indicates that copper is acting to decrease VO₂ at a higher level of integration than the individual tissues. In animals subjected to an increase in temperature as well as sublethal copper, oxygen consumption was higher than controls five days after the temperature was increased, indicating a delay in temperature acclimation. This increase was reflected in higher in vitro oxygen consumption in the liver and gill indicating that sublethal copper delays temperature acclimation by acting directly on the tissues. Tissue copper accumulation was seen first in the gills followed by accumulation in the liver. Copper was not found to accumulate in the brain. Increased copper levels were found in the bile at all tested exposure times. A discussion of the ecological implications of these findings is included. / M. S.

Changes in heart rate, ventilatory activity and oxygen consumption were determined in trout (Salmo gairdneri) and brown bullhead catfish (Ictalurus nebulosus) during exposure to a steadily increasing concentration of waterborne cyanide selected to produce death in 8-9 hours for each species. The lethal cyanide concentration for the bullheads was an order of magnitude higher than for trout. Trout developed an immediate and gradually increasing bradycardia throughout the exposure period. Cyanide produced tachycardia in the bullhead followed by a gradual onset of bradycardia as the concentration of cyanide was raised. Pericardial injection of atropine (a muscarinic cholinergic antagonist) indicated that bradycardia in the trout was due initially to increased vagal tone but later due to the direct effect of cyanide on the heart. Hyperventilation in the trout persisted throughout the exposure period, although the rate and amplitude fluctuated and was variable between individual fish. During the last hour of exposure (highest cyanide concentration), ventilation was characterized by rapid, shallow breaths with a sudden respiratory arrest. The bullheads showed hyperventilation during the first 3 hours of exposure followed by a gradual, linear drop in ventilation rate and amplitude until death occurred. Cardiac and ventilatory responses in both species were attributed to stimulation of central and peripheral chemoreceptors by cyanide. Evidence is presented which suggests the initial response in the bullheads was due, at least in part, to gustatory stimulation by the cyanide. Oxygen consumption of the trout remained above pre-exposure levels for the majority of the test period. Oxygen consumption in the bullhead paralleled the changes in heart and ventilatory rates. Whole-body lactate and pyruvate levels of fingerlings of both species during cyanide exposure were measured to estimate the extent of anaerobiosis. Whole-body lactate levels were greater in the bullheads than the trout, indicating a higher capacity for anaerobiosis, probably due to a greater fuel supply. Whole-body pyruvate levels in both species did not change from control levels until the last hour of cyanide exposure. / M.S.

This study was conducted from March 3, through June 2, 1951, in order to determine to what extent pathogenic bacteria were entering the Trinity River between East Fort Worth, Texas and South Dallas, Texas, from municipal sewage disposal plants.

The purpose of this study was to compare the simultaneous effects of the water soluble fraction (WSF) of JP-4, a common military and civilian jet fuel, on survival, ventilatory rate, preference-avoidance behavior, and blood enzymes and ions of the bluegill sunfish (Lepomis rnacrochirus) to determine possible interrelationships and which procedures might be most descriptive of sublethal stress. The dynamic 96-h LCSO for WSF JP-4 was 26.2% (percent of the maximum soluble amount of JP-4). A concentration of 5.1% WSF JP-4 caused a detectable shift in ventilatory functions (rate and amplitude); this concentration was equivalent to the 96-h LCOl. Fish did not display a strong preference-avoidance reaction when exposed to WSF JP-4. Some avoidance occurred at 3.5% and 4.9% WSF JP-4. At concentrations near the 96-h LCSO fish appeared to lose their ability to detect WSF JP-4, indicating potential for fish not to avoid lethal levels of WSF JP-4. Few significant changes in whole and serum blood parameters were measured in fish exposed to 13% WSF JP-4; at near lethal concentrations changes were primarily attributed to osmoregulatory failure. Therefore such changes in blood parameters would not be useful to validate or confirm exposure to WSF JP-4. There were few significant changes in gill and liver histology of fish exposed to WSF JP-4 other than an increase in size or number of lipid vacuoles in the liver of exposed fish. / Ph. D.

This research describes aquatic macroinvertebrate community responses to heavy metals (copper, zinc) in experimental streams and at metal-impacted sites in the field. Experiments employed substrate-filled trays which were colonized in the field and then transferred to laboratory or outdoor streams. Laboratory experiments conducted over three seasons showed that acute (96 h) exposure to copper (Cu) at 15-32 μg Cu/L significantly reduced macroinvertebrate abundance and number of taxa during each season. Owing to differences in sensitivity among taxa, the percent composition of dominant groups varied between control and dosed streams. Mayflies were quite sensitive to Cu, particularly during the summer when water temperatures were higher. Community responses to Cu and Zn in outdoor experimental streams were similar to those observed at metal-impacted sites in the field. Control streams and field reference Stations were dominated by mayflies and Tanytarsini chironomids. In contrast, treated Streams and impacted field sites were dominated by net-Spinning caddisflies (Hydropsychidae) and Orthocladiini chironomids. The similarity of these experimental results to those observed in the field suggest that macroinvertebrate community responses to heavy metals are highly predictable. Responses of these communities to Cu were greatly influenced by water quality. Effects were more severe in New River Streams, where water hardness and alkalinity were low, compared to Clinch River Streams, where hardness and alkalinity were higher. In soft water Streams, abundance was reduced by 84% after 10 d exposure to Cu (measured concentration = 13 μg/L). In contrast, abundance was reduced by only 45% in hard water Streams after 10 d at Similar Cu levels. These results demonstrate the importance of accounting for water quality characteristics of receiving systems when establishing site-specific criteria for metals. Chronic exposure (14 d) to sublethal levels of Cu (< 6 μg/L) increased Vulnerability of caddisflies (Hydropsyche morosa and Chimarra sp.) to predation by the Stonefly, Paragnetina fumosa. Caddisflies were also the major component of stonefly diets and were consumed Significantly more frequently in dosed Streams than controls. These results demonstrate that single Species bioassays were inadequate for predicting effects of toxicants on community level processes. / Ph. D.

Effects of hexavalent chromium on the life cycle of Chironomus riparius were examined in the laboratory, using sublethal (0.5 mg/1) and 40% lethal (2.0 mg/1) concentrations. Chironomus egg masses were introduced into both control and chromium-treated 21 1 aquaria. Larvae were subsampled at 5-day intervals, measured for length, and weighed to generate growth curves. Emerging adults were allowed to mate and oviposit. Twenty female pupae were collected from control and treatment (0.5 mg/1) populations within 12 hours of pupation. Their bodies were analyzed for lipid content by calculating loss in dry weight after a chloroform-methanol extraction. Chromium body burdens were measured in both larvae and adults from treatment (2.0 mg/1) and control populations. Effects of chromium on hatching rates of egg masses were studied. Growth was stimulated at both lethal and sublethal concentrations of chromium. Lipid content of female pupae was significantly higher in treatment populations than in controls. Both stimulated growth and increased lipid storage may be the results of metal activation of enzymes involved in energy processing and storage in the insect. Reproductive success, as measured by numbers of offspring per adult female, declined with increasing chromium concentrations. Chromium concentrations in adult males and larvae were significantly greater for treatment populations. Metal body burdens may have become concentrated in eggs or sperm of Chironomus and caused the observed decrease in reproductive success. No direct toxicity of chromium on egg masses was observed at concentrations up to 5 mg/1. / M.S.

The suitability of the open, stirred-jar technique as a method to estimate oxygen-uptake due to degradation of organic waste and nitrification by suspended microbes was studied. With this procedure, both the concentration of waste and the reaeration rate can be set to values similar to those expected in the stream. Thus, the conditions in the jars resemble the deoxygenation process in the stream more closely than the BOD-bottle test. There is no need of assuming any particular type of kinetic behavior, because the procedure gives directly an oxygen-uptake curve. Long lags before nitrification were observed. In most experiments, the oxygen-uptake rate during the nitrification stage increased slowly, resembling a first-order increasing or autocatalytic behavior. When a waste with a low COD:TKN ratio was used, the oxygen-uptake rate was constant and low, resembling zero-order kinetics. The results showed that accurate estimates of oxygen-uptake can be obtained with the open stirred-jar test. The oxygen-uptake patterns include variations in the oxygen-uptake rate that are smoothed out when the classical BOD-bottle test and the first-order model are used. / M.S.

Surface water pollution is prevalent in numerous areas of central Roodepoort mainly due to gold mining activities. The surface water quality for the Bosmontspruit, Russell’s Stream and the New Canada Dam was assessed from October 2010 to March 2011. Physical, chemical and biological characteristics of the water were determined for 8 monitoring points and the results obtained were compared with the In-stream water quality guidelines for the Klip River catchment and the South African Water Quality Guidelines. A trend noticed throughout the sampling period was the non-compliance in the levels of total dissolved solids (TDS) and dissolved oxygen. The results indicated that concentrations of iron, aluminium, nickel, manganese and potassium were above the limit across the Bosmontspruit and Russell’s stream. There was also significant evidence of excessive faecal coliform and ammonium pollution in the Bosmontspruit. During the monitoring period it was noted that water from these streams were utilised for crop irrigation, bathing, livestock and human consumption and may pose a health hazard due to poor water quality. / Environmental Sciences / M.Sc. (Environmental Science)