Overabundant nitrate in Iowa’s surface water threatens stream health, drinking water safety, and significantly contributes to hypoxic zones in the Gulf of Mexico. Researchers have quantified surface water nitrate loads historically with grab samples and, more recently, in-situ sensors. In-situ sensor networks capture changes in nitrate concentration over small time scales, providing high temporal resolution data to accurately calculate nitrate loading. However, because advanced sensors are expensive, spatial resolution is often compromised when sensors are deployed on large rivers. To collect high spatial resolution nitrate samples that complement the high temporal resolution data from in-situ sensors, we first used traditional grab samples on small, non-navigable streams in the Clear Creek and the English River watersheds. Dense grab samples across watersheds provide higher resolution data, but not at the spatial resolution achievable on navigable streams with newly developed, boat-deployed sensor technology. We constructed a boat-deployed sensor system that automatically measured nitrate concentrations, temperature, dissolved oxygen, conductivity, and pH as we navigated a boat on a given waterbody. We used the system on the Iowa and Cedar Rivers to capture spatial and temporal changes never previously observed in Iowa. Our data suggest nitrate concentrations and yields were highest in low-relief landforms dominated by row crop agriculture. Nitrate concentrations were lower in higher-relief landforms with less row crop production. We also measured water in Storm Lake, IA with the boat-deployed system. We measured little heterogeneity of nitrate concentrations in the lake, but observed significant nitrate reduction in a large wetland just upstream. The system captured fine scale spatial dynamics of nitrate reduction in the wetland and low nitrate concentrations throughout Storm Lake. Our newly developed sensor platform captured high resolution water quality data, complementing the high temporal resolution data collected with in-situ sensors. High spatial resolution data in this and similar studies provide powerful insights for decision makers to target problematic areas, reduce nitrate, and improve water quality.

Waterborne disease is a significant contributor to the global burden of disease, in particular among high-risk populations in developing nations. State-of-the-art methods for the enumeration of microbial pathogens in drinking water sources have important limitations, including high initial cost, 24-48 hour delays in results, high staffing and facility requirements, and training requirements which all become especially problematic in the developing nation context. A number of alternative approaches to microbial water quality testing have been proposed, with the goal of decreasing the required testing time, decreasing overall costs, leveraging appropriate technology approaches, or improving sensitivity or specificity of the water quality testing method. One approach that may offer solutions to some of these limitations involves the deployment of sensor networks using fluorescent spectroscopy to detect intrinsic protein fluorescence in water samples as a proxy for microbial activity. In recent years, a number of researchers have found significant and meaningful correlations between indicator bacteria species and the protein fluorescence of drinking water samples. Additionally, advances in the semiconductor industry could be used to drive down the cost of such sensors. This technology may also be extensible to other water quality parameters, including dissolved organic matter or the presence of fluorescent pollutants. In this thesis, a literature review describes the fundamentals of fluorescence spectroscopy, historical and recent work regarding the fluorescence of the amino acid tryptophan and associated bacterial fluorescence, possible mechanisms for this association, and potential applications of this technology for drinking water quality monitoring and waste water process control. Extensibility of the technology is also discussed. Next, experimental methodology in reproduction of similar results is described. Samples were taken from seven (7) surface water sources and tested using membrane filtration and an off-the-shelf fluorescence spectrometer to help examine the association between the presence of indicator bacteria and the tryptophan fluorescence of the water sample. The results, showing an association of R2 = 0.560, are compared to the results of recent similar experiments. Finally, two prototypes are described, including their design requirements and data from prototype testing. The results of the testing are briefly discussed, and next steps are outlined with the goal of developing a low-cost, in-situ microbial water quality sensor using fluorescence spectroscopy principles.

Thesis (M.Sc. (Zoology)) --University Limpopo, 2013 / Major anthropogenic activities such as, mining, coal-fired power stations and intensive agricultural practices in the upper catchment area of the Olifants River, have a dramatic impact on the water quality downstream. As a result the river is presently the third most polluted river in South Africa. The aim of this study was to assess the impact of water and sediment quality on the health of Labeo rosae and Schilbe intermedius. The aim was accomplished by applying the Fish Health Assessment Index (HAI) which includes the Parasite Index (PI) at Flag Boshielo Dam in the Middle Olifants River, Limpopo Province. This was achieved through; assessing the water quality of the dam by determining the levels of physical and chemical constituents in the water at three sampling sites, determining the bioaccumulation of selected metals in the muscle tissue of the two fish species, assessing the fish health (including the fish condition factor) and the fish parasites in the dam by using the fish HAI and PI, and ascertaining the Human Health risk factor upon consumption of fish contaminated with metals from the dam. The water and sediment quality were seasonally sampled at three sites in the dam: inflow, middle and wall. Dorsal muscle tissues from both fish species were collected for metal bioaccumulation analyses. The water, sediment and fish muscle tissue samples were analysed by an accredited laboratory by means of ICP-OES spectrometry. For the fish health and parasites, ten fish per species were collected seasonally (July 2009 to April 2010) by means of gill nets and examined at a field laboratory using the HAI and PI protocol. Generally the water quality of Flag Boshielo Dam was acceptable for aquatic ecosystems according to the SAWQG with the exception of phosphorus and some metals at the inflow area. The pH ranged between slightly acidic to alkaline values; water temperature: 15°C to 26°C; water hardness medium soft, salinity within the freshwater range; turbidity in the clear water range. The TDS and major ions (salts) were acceptable for the duration of the study. The highest concentrations of nutrients (specifically phosphorus) as well as metals (aluminium, cadmium, copper, iron and lead) were recorded at the inflow area of the dam. The nutrients were very low except the eutrophic range phosphorus concentrations recorded at the inflow whereby, the Elands River may be an additional source of nutrients into Flag Boshielo Dam. The metals that were recorded above TWQR are; aluminium, cadmium, copper, iron and lead, of which were mostly recorded at the inflow. However, statistically there was no significant difference among the three sampling sites. The metal concentrations at the inflow were recorded only slightly higher than the middle and the dam wall. The main source of the metals may be the water coming from catchment area of the dam given the intensive agricultural activities taking place between Loskop Dam and Flag Boshielo Dam. Sediment and bioaccumulation: All the metals were recorded at higher concentrations in the sediment than in the water and fish muscle tissue, except antimony, selenium and strontium. The most abundant metals recorded in the sediment were iron and aluminium. However, the concentrations above the TEL were cadmium, nickel and zinc. The elevated metal concentrations in the sediment are indicating that the metal load in the sediment of Flag Boshielo Dam could be a potential risk for the aquatic biota if they become bioavailable. Antimony, selenium and strontium metal concentrations were recorded at higher concentrations in the muscle tissue of both fish species than in the sediment and water. Iron was the most accumulated metal in the muscle tissue of both fish species. In terms of numbers, more metals were recorded in the muscle tissue of S. intermedius than in L. rosae however the metal concentrations were higher in the latter. This can be attributed to their different trophic levels in the food chain; L. rosae is a primary consumer while S. intermedius is a tertiary consumer. However, the metals that accumulated in the fish muscle tissue were indicative of bio-availability of the toxic metals in the dam and not water/sediment pollution. According to a Human Health risk assessment (Chapter 3), metals that may have risks upon consumption of L. rosae are; antimony, arsenic, chromium, iron and vanadium; for S. intermedius are; antimony, chromium, iron, vanadium and arsenic (in descending order). These metals may pose toxic and carcinogenic risks to humans. Therefore, the rednose labeo (L. rosae) and to a lesser extend the silver catfish (S. intermedius) fish species from Flag Boshielo Dam may not be suitable for humans if consumed above 350 g per week. Fish health and parasites: The Health Assessment Index (HAI) values of the two fish species differed significantly with higher index values recorded for S. intermedius than L. rosae. Besides the Parasite Index (PI), abnormal haematocrit readings, liver conditions, skin lesions and clubbed gills are the necropsy anomalies that contributed predominantly to the HAI. Overall, the PI contributed mostly to the total HAI value. The parasite load and therefore also the mean intensity, mean abundance and prevalence of S. intermedius were higher during all seasons than that of L. rosae. The dominant ectoparasites for both species were from the Class Monogenea and the dominant endoparasites were nematodes. Out of 40 L. rosae sampled, 139 parasites were retrieved; five parasite species were ectoparasites and two endoparasites. From the 40 S. intermedius sampled, 2473 parasites were retrieved, from which two species (one genus) were ectoparasites and three species were endoparasites. The condition factor is used to compare the “condition”, “fatness” or wellbeing of fish and it is based on the hypothesis that heavier fish of a particular length are in a better physiological condition. The L. rosae had a better condition factor, recorded at values less than (2) as compared to S. intermedius (>2). The cause of the HAI necropsy anomalies may have been also from parasite load other than the metals in the water and sediment. However, the HAI alone cannot be used for metal pollution, unless it is done in conjunction with a histopathological study of the tissues/organs. Therefore, the cause of the recorded anomalies from both fish species is inconclusive. On the hand, fish can be used as bioindicators because the accumulated metals in the fish tissues are indicative of the bioavailability of metals in Flag Boshielo Dam.

Includes bibliographical references (p. 319-347) Mode of access: Internet via World Wide Web. Available at: http://business.unisa.edu.au/waterpolicylaw/documents/thesis.pdf Selected for archiving SSL

Appropriately constructed pollutant export models can help set management priorities for catchments, identify critical pollutant source areas, and are important tools for developing and evaluating economically viable ways of minimising surface water pollution.¶ This thesis presents a comparison, an evaluation and an integration of models for predicting the export of environmental pollutants, in particular sediment, through river systems. A review of the capabilities and limitations of current water quality modelling approaches is made. Several water quality and quantity modelling approaches are applied and evaluated in the catchment of the upper Murrumbidgee River.¶ The IHACRES rainfall-runoff model and a simple hydrologic routing model are applied with the aim of developing a capacity to predict streamflow at various catchment scales and to enable integration with other pollutant load estimation techniques. Methods for calculating pollutant loads from observed pollutant concentration and modelled streamflow data are also investigated. Sediment export is estimated using these methods over a 10-year period for two case study subcatchments. Approaches for water quality sampling are discussed and a novel monitoring program using rising stage siphon samplers is presented. Results from a refinement of the Sediment River Network model in the upper Murrumbidgee catchment (SedNet-UM) are presented. The model provides a capacity to quantify sediment source, transport and to simulate the effects of management change in the catchment. The investigation of the model includes rigorous examination of the behaviour of the model through sensitivity assessment and comparison with other sediment modelling studies. The major conclusion reached through sensitivity assessment was that the outputs of the model are most sensitive to perturbation of the hydrologic parameters of the model.¶ The SedNet-UM application demonstrates that it is possible to construct stream pollutant models that assist in prioritising management across catchment scales. It can be concluded that SedNet and similar variants have much potential to address common resource management issues requiring the identification of the source, propagation and fate of environmental pollutants. In addition, incorporating the strengths of a conceptual rainfall-runoff model and the semi-distributed SedNet model has been identified as very useful for the future prediction of environmental pollutant export.

Thesis (M.S.)--University of Nevada, Reno, 2005. / "May, 2005." Includes bibliographical references. Online version available on the World Wide Web.

Temperature, conductivity, and Aeromonas hydrophila density were determined bimonthly at six sites in the White River drainage system, Delaware County, Indiana, from April, 1984 through December, 1984. Fish were collected from four of the six sites. Fish were identified to species, examined for gross pathology, and their blood collected. Titers against A. hydrophila antigen 157 were determined for all carp (Cyprinus carpio) captured. Certain carp serum samples were also tested against three additional A. hydrophila antigens.Aerononas hydrophila densities appeared to be related to temperature and conductivity, primary producers, and runoff/effluent. Aeromonas hydrophila densities were higher in areas affected by urban runoff/ effluent than in areas affected by rural runoff/effluent. Aeromonas hydrophila densities increased as one progressed through the city of Muncie.Only five percent of all fish captured exhibited signs of gross pathology. Diseased fish typically demonstrated low titers against antigen 157. Several A. hydrophila serotypes were apparently infectious for the carp studied. Thirty-two percent of the carp sampled exhibited a positive titer response against antigen 157. Considerable variation in titer response existed between individuals.Ball State UniversityMuncie, IN 47306

Thesis (Ph. D.)--Ohio State University, 2004. / Title from first page of PDF file. Document formatted into pages; contains xiii, 253 p.; also includes graphics (some col.). Includes abstract and vita. Advisor: Earl F. Epstein, Dept. of Natural Resources. Includes bibliographical references (p. 228-238).

No description available.

Introduction Lake Mzingazi is the only suitable source of domestic water supply for the Richards Bay community. Rapid industrialisation in the city of uMhlathuze, accompanied by an influx of people, has resulted in informal settlement occurring around the lake. The uncontrolled activities of this development threaten to pollute the water source. Previous studies in1979 conducted by Council of Scientific & Industrial Research indicated that Lake Mzingazi water was still within acceptable limits in terms of the Department of Water Affairs & Forestry guidelines. The lake water quality was that of a Class I water resource, which is excellent for domestic use. Pollution of the lake can result from diffuse sources of pollution due to settlement of communities around it. Water purification costs could escalate thus forcing an increase in water tariffs. If pollution resulted in the lake being unable to be utilized, the Richards Bay community will be seriously affected, as it would necessitate the importing of water from distant regions. Either way, the expense of acquiring water would increase. All living organisms rely on adequate water for their survival. Worse still are human beings for their water should not only be adequate but should be of good quality to prevent health risks and even death. It is in view of these possibilities that the study was undertaken. Aim The aim of the study is to assess the extent of physical, chemical and biological pollution in Lake Mzingazi due to non-point sources and to recommend necessary protection measures that need to be implemented to prevent any negative health impact on surrounding communities. At present there are no restrictions and no protection of the lake from pollution except that no recreation is allowed into the lake at present. Methods Several objectives were set in order to focus on specific issues. One of the objectives was to inform the communities around the lake about the study. Sampling of the lake water was conducted monthly from June to November 2006 (using a boat). Pictures of areas around the lake were also taken for further analysis. At each sampling run, 36 samples were taken and delivered to a laboratory accredited by the South African National Accreditation Standards for analyses. Six sampling runs were completed. Secondary data for the period of 1998 to 2005 were obtained from uMhlathuze Municipality in order to establish pollution trends and for comparison purposes with the Department of Water Affairs and Forestry guidelines. Results The findings of the study revealed that the quality of the lake water is still within acceptable limits when compared with the Department of Water Affairs & Forestry guidelines; however, informal settlement threatens the future of the lake by encroaching into the lake banks. Discussion There is definitely a risk of pollution to Lake Mzingazi as long as there are no pollution prevention plans in place. Recommendations All data should be stored in a centralized information system to avoid losing valuable information. The Water Services Authority must develop and maintain a water quality-monitoring programme that will capture all changes occurring in the lake. / Thesis (MMed.)-University of KwaZulu-Natal, Durban, 2009.