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published_or_final_version / Chemistry / Master / Master of Philosophy

A statistical analysis of water quality data collected on paired agricultural watersheds was undertaken. The objective of the study was to evaluate trends in water quality. The data sets that were used to determine the changes in water quality were taken from the project "Gestion de leau dans le bassin versant de la partie superieure du ruisseau St. Esprit". For the period from 1994 to 1996, the analysed water quality parameter were nitrate, phosphate, ammonium, potassium, total Kjeldahl nitrogen, total phosphorus and suspended sediment. / The data sets were analysed using descriptive statistics, graphical techniques and non-parametric methods to detect trends in the measured water quality parameters. The statistical analyses were undertaken to determine the effects of soil conservation practices and fertiliser management and to compare different sampling strategies. / The analyses showed that there were no detectable changes in water quality over the 3-year period related to the conservation practices. The lack of improvement in water quality might be due to the slow rate of adoption of conservation practices and to climatic variations. / For the non-parametric methods applied, it was possible to show that climatic variations on small watershed affect the results over a short time period (<5 years). The phosphate concentration on the control showed a significant upward trend. The nitrate concentration on St. Esprit showed an upward trend over the 3-year period and then downward trend after a 4-year period of water quality data. This was likely due to the implementation of best management practices. / The statistical analyses showed that weekly sampling on fixed schedule produce the same results as automated sampling based upon flow rate related to a defined discharge. This shows that the more complex and expensive flow weighted sampling scheme is not required to detect trends in water quality.

A handheld InfraRed (IR) Carbon Dioxide (CO2) gas detector was developed and used to carry out a study of water and urine samples in South Africa. The details of the model and the results of the study are discussed here. The overseas markets are not geared for the current South African conditions. Use is made of components that can be obtained locally. Imported components are very expensive and should an imported model be damaged, it has to be returned overseas to be repaired. As an illustration of this technology it was decided to perform research in water technology and then develope a handheld Infrared CO2 gas detector based prototype which would: highlight the benefits of using handheld IR CO2 gas detectors; be built locally; be powered by a 12 Volt supply; be very easy to maintain; and be cost effective. Experimental results on the accuracy and stability of the instrument formed part of this study. The IR CO2 Gas detector that was developed was used throughout the project as a prototype and testing vehicle for numerous designs. It proved to be superior to the current imported commercial instruments in terms of size, cost effectiveness and user friendliness. A further advantage of the instrument is its robustness.

No description available.

For temperate lakes which receive a variable nutrient loading with seasonal variance in their hydrology, it is necessary to consider the dynamic response of the lake to these variable nutrient loadings. An approach to evaluate Lake Eola water quality responses to dynamic discharge of nutrients is presented. The major source of nutrients for this lake is stormwater runoff containing nitrogen and phosphorus. A mass balance of nutrient sources and sinks for the period of one year (April 1980 - March 1981) was performed. To accomplish this, a field determination for various parameters of the hydrologic budget was performed on a monthly basis. A monthly water quality analysis of the lake was measured. It was determined that Lake Eola was phosphorus limited and that 87% of the Total Phosphorus entering the lake via stormwater runoff was retained in the bottom sediments. Retention of various nutrients ranged from 77% to 93%. In order to evaluate the dynamic response of this lake, it was necessary to consider the retention of the nutrients as a function of time. The inductive methodology for this analysis and an example for Total Phosphorus is presented.

A water sample concentrator utilizing a membrane adsorption/elutriation procedure for bacterial recovery was developed and field-tested. Influent sample volumes of 19.0 liters were processed by the concentrator within 10 minutes. Standard MPN and membrane filtration tests were conducted to determine the efficiency of the concentrator. In laboratory experiments, an average bacterial recovery of 48 percent was accomplished when E. Coli was the bacterium concentrated. An average recovery of 78 percent was achieved with Streptococcus faecalis. Various commercially available 142 mm diameter membrane filters were tested with the concentrator. Millipore membrane filters having a porosity of 0.45 m were found to be superior to Cox membrane filters with 0.45 and 5.0 m porosities and to zeta plus filters. The most promising technique for eluting bacteria from the membrane filter appeared to consist of mixing the filter and 125 mL of three percent bovine serum solution at pH 9.0 in an electric blender for 30 seconds and then allowing 15 minutes of contact. Miscellaneous experiments investigated the addition of multivalent cations to enhance adsorption of bacteria to the membrane filters, the use of vacuum induced flow through the concentrator and the possibility of monitoring bacterial levels through adenosine triphosphate analysis. In the field trials, the water sample concentrator detected coliform bacteria in drinking water in which no coliforms were detected in grab samples by the standard MPN method. / Master of Science

A two-year study was conducted at the Narellan Creek Catchment between September 1998 and August 2000. To improve the quality of the water that flows in to the Nepean River, the Harrington Park retention basin was enlarged and rehabilitated from 7.0 ha to 12.0 ha area. This study measured several parameters of water quality to assess the efficiency of the Harrington Park retention basin for water quality improvement. Three sampling sites – the Camden Valley Way (CVW), Harrington Park retention basin (HPK) and Kirkham Lane (KLN) were selected for sample collection. Water flows from CVW to HPK then to KLN and finally to the Nepean River. Rainfall, water level, discharge rate and ambient temperature were recorded at the KLN site while the selected water quality parameters were determined at all the three sites. Low flow samples were manually collected at monthly intervals. An auto-sampler which collected water samples during rain events (for high flow data) was set up at the KLN site. Rising stage samplers which collected water at different water levels during a rain event, was set up at all the sites but data from this device was found to be of limited use due to the varying time lags between the filling of each bottle. Statistical analyses by various measures show that the Harrington Park retention basin played a significant role in improving the upstream and in-stream water quality. These study shows that constructed wetlands like the Harrington Park retention basin has the ability to significantly improve the water quality of a catchment. The water quality improvement is greater at lower water flow rates. / Doctor of Philosophy (PhD)

The sensitivity of bluegill (<i>Lepomis macrochirus</i>) to low pH in soft (12 or 18 mg/L CaCO₃) and hard (165 or 197 mg/L CaCO₃) water was compared in five day laboratory toxiclty tests. Embryo-larval bluegill were exposed to pH levels ranging from 3.8 to 7.0 in soft water and from 3.8 to 8.0 in hard water. An on-site toxicity test, using lake water (3.4 mg/L CaCO₃) adjusted to pH levels ranging from 3.5 to 7.3, was conducted to compare laboratory and field results. At low pH, hatching was reduced, the hatching period prolonged, and the incidence of partial hatching increased. Increased water hardness mitigated acid toxiclty, enhanced larval survival, and promoted hatchability. Hatching rates were decreased over those of the controls by 76 percent in soft water and by 23 percent in hard water at pH 4.0, and hatching was negligible at pH 3.8. The length of the hatching period was prolonged by 24 to 48 hours at pH levels ≤4.6. Partial hatching averaged 43 percent in pH 4.4. Increasing acidity resulted in increased embryo-Iarval mortality, averaging >62 percent at pH levels ≤4.6; mortality was 100 percent at pH levels <4.4 in soft water and 3.8 in hard water. Bluegill larvae were more sensitive than eggs. The embryo-larval LC50's were pH 4.67 in soft water and pH 4.06 in hard water; LC1's were pH 5.66 in soft water and 5.04 in hard water. In the on-site field experiment, approximately 50 percent mortality occurred at pH 4.6 which was nearly identical to the LC5O of pH 4.67 in laboratory (soft water). Growth of larvae was not affected by low pH. As acid levels increased, yolk-sac volumes decreased, physical deformities (fin, eye, and spinal abnormalities) increased and behavioral abnormalities were evident. Yolk-sac volume was decreased at pH levels <5.5 in soft water and <5.1 in hard water, perhaps reflecting higher energy expenditures by larvae held at sublethal pH levels. Spinal curvature and fin erosion of larvae were apparent at pH levels <5.25 in soft water. Larvae were lethargic and swimming ability was impaired at pH levels ≤5.5 in soft water and ≤5.1 in hard water. Exposure of embryo-larval bluegill to low pH levels (<5.7) in soft water may compromise their ability to survive, forage efficiently, and escape predation under natural conditions. / Master of Science

Two approaches for the examination of microbially-caused degradation of water quality within water distribution systems were considered: the results of a questionnaire were analyzed and a sampling technique utilizing a concentrator was evaluated. A questionnaire, completed by water treatment plant operators in Virginia, was analyzed to ascertain what complaints regarding water quality were being received and what the causes of the complaints were. The most frequently reported complaints were those of taste and odor. Although they were not the sole factor, it appears nuisance bacteria were causative agents in degradation problems related to turbidity and red water. The Pellicon cassette system concentrator was evaluated for use during sampling in water distribution systems. The evaluation included determining the range of percent recovery in the retentate to be expected and the factors affecting this recovery. Thirty to sixty percent recovery of bacteria (Pseudomonas cepacia or Escherichia coli) in the retentate can be expected. The percent reduction in volume was the system parameter which most affected the percent recovery. / Master of Science