A watershed scale water quality evaluation system was developed for assessing spatial variation of subsurface pesticide movement. The system consists of a linked-transport model component for performing simulation and a GIS component for processing spatially-related data. The surface heterogeneity caused by agricultural activities, topographic, hydrologic, and soil type variations in a watershed was handled by partitioning the watershed into homogeneous subfields. The subsurface soil profile and aquifer heterogeneities were considered by dividing the subsurface domain into root zone, intermediate vadose zone, and saturated zone, respectively. On each of the homogeneous subfields, the physically-based models, PRZM and VADOFT, were linked to simulate pesticide transport in the root and intermediated vadose zones. Pesticide movement in groundwater underneath the watershed was simulated by linking the other two models with SUTRA. An irregular shape finite element mesh generator was developed for fitting the irregular shape watershed boundary and reducing the number of nodes of the finite element mesh. Either transient or steady state flow and transport simulation could be performed with the system. The system is able quantitatively to produce detailed spatial variation maps of pesticide concentrations at any desired depth in the unsaturated zone and in groundwater. The system requires spatially-distributed information as inputs. Management of large volumes of spatially-referenced data which represent the heterogeneous properties of the watershed were facilitated by a developed GIS component. The GIS data processing component was composed of spatial data manipulation and display, attribute database management, and model input information extraction subcomponents. The spatial data processing component consists of data format conversion, map registering, map editing, new information generation, and map display subcomponents. / Ph. D.

published_or_final_version / Environmental Management / Master / Master of Science in Environmental Management

Thesis (M.S.)--University of North Carolina at Wilmington, 2005. / Includes bibliographical references (leaves: 48-49)

M.Sc. (Aquatic Health) / Sediments can contain a variety of organic and inorganic contaminants. These contaminants accumulate, resulting in extremely high concentrations even once the overlying water concentrations are at or below acceptable water quality guidelines. Any changes in the physical parameters of the overlying water can cause these pollutants to be released back into solution. Accumulated contaminants can be released at even higher concentrations than previously detected. In recent years, sediment contamination has highlighted the need to monitor these previously overlooked pollutant sources that have accumulated in aquatic ecosystems. South Africa does not currently have standardised methods to assess sediment toxicity. Although international methods exist, they are largely untested in South Africa and the organisms needed to conduct these tests are not readily available. Over the years numerous culture methods have been develop globally for culturing organism to be used for water and sediment toxicity tests. In South Africa, the focus has mainly been on culturing organisms for water toxicity testing. Sediment toxicity testing with indigenous organism however, was not developed. Established international culture methods from the United States Environmental Protection Agency, the Organisation for Economic Cooperation and Development, and Environment Canada were taken into consideration when developing the laboratory culture method for two(2) of the selected organisms (Chironomus spp. & Hydra sp.) from this study. A preliminary culture method was also developed for the third selected organism, Melanoides tuberculata (gastropod). The organisms cultured in this study were selected based on their extent of contact with the substrate, ease of handling, availability, culture maintenance as well as their reproductive cycle. The Hydra, Chironomids and M. tuberculata cultures were successfully breeding under laboratory conditions and remained stable. The Chironomus sp. and M. tuberculata maintain contact with the sediment making them suitable as ecologically relevant organisms for use in whole sediment toxicity testing in South Africa.

Southwestern Indiana has numerous lakes developed in abandoned coal mine spoils which support recreational sports fisheries. Some lakes, due to exposure to acid mine drainage from coal wastes and pyritic spoils, are unsuitable habitats for fisheries development. This study examines a publicly owned acid mine lake with an area of approximately 51 ha, following reclamation and elimination of acid producing areas in its drainage basin. Fifteen physico-chemical sample collections were made over a thirteen month period (1991-1992). Parameters sampled included pH, total acidity, iron, manganese, and aluminum. Comparisons were made to historic pre-reclamation water quality data and to established models of acid mine lake recovery. Due to the local topography and exposure to prevailing winds, the lake was generally well mixed throughout the study. Virtually no summer stratification was found, but typical winter season stratification occurred. The water column was well oxygenated throughout the study. Secchi disk transparency varied from 2.5 m to clear to lake bottom (6 m). This study found no significant change in lake water pH (2.9-3.0 to 3.0-3.2 s.u.) since reclamation activities in 1988. However, changes in total acidity and total metal concentrations had occurred since reclamation which suggested that the lake was in early recovery stages. No trends in water quality improvement were determined which could assist in planning toward the eventual establishment of a sports fishery. / Department of Biology

The prevention of outbreaks of waterborne diseases remains a major challenge to public health service providers globally. One of the major obstacles in this effort is the unavailability of on-line and real-time methods for rapid monitoring of faecal pollution to facilitate early warning of contamination of drinking water. The main objective of this study was to develop a β-glucuronidase (GUD)-based method that could be used for the on-line and real-time monitoring of microbial water quality. GUD is a marker enzyme for the faecal indicator bacteria Escherichia coli. This enzyme breaks down the synthetic substrate p-nitrophenyl-β-D-glucuronide (PNPG) to D-glucuronic acid and p-nitrophenol (PNP), which turns yellow under alkaline pH. The enzymatically produced PNP was used to detect GUD activity. In situ GUD assays were performed using running and stagnant water samples from the Bloukrans River, Grahamstown, South Africa. The physico-chemical properties of environmental GUD were determined, after which a liquid bioprobe and a microbial biosensor modified with Moraxella 1A species for the detection of the enzyme activity were developed. In order to determine the reliability and sensitivity of these methods, regression analyses for each method versus E. coli colony forming units (CFU) were performed. The storage stabilities of the bioprobe and biosensor were also investigated. The physico-chemical properties of in situ GUD were different from those of its commercially available counterpart. The temperature optimum for the former was between 35 and 40 °C while for the latter it was 45 °C. Commercial (reference) GUD had a pH optimum of 8.0 while the environmental counterpart exhibited a broad pH optimum of between pH 5.0 and 8.0. The liquid bioprobe had a limit of detection (LOD) of GUD activity equivalent to 2 CFU/100 ml and a detection time of 24 h. The method was less labour intensive and costly than the culturing method. The liquid bioprobe was stable for at least four weeks at room temperature (20 ± 2 °C). The biosensor was prepared by modifying a glassy carbon electrode with PNP degrading Moraxella 1A cells. The biosensor was 100 times more sensitive and rapid (5-20 min) than the spectrophotometric method (24 h), and was also able to detect GUD activity of viable but non-culturable cells. Thus it was more sensitive than the culturing method. Furthermore, the biosensor was selective and costeffective. The possibility of using a Pseudomonas putida JS444 biosensor was also investigated, but it was not as sensitive and selective as the Moraxella 1A biosensor. The Moraxella biosensor, therefore, offered the best option for on-line and real-time microbial water quality monitoring in South African river waters and drinking water supplies.

M.Sc. (Zoology) / Sediment contamination occurs as a result of various anthropogenic activities; mainly through mining-, agricultural- and industrial practices. Many of the contaminants arising from these activities enter the aquatic system and precipitate from the surrounding water, binding to sediment particles. In the sediment compartment, these contaminants reach concentrations much higher than in solution with the overlying water. Even though the quality of the overlying water may prove acceptable in accordance to water quality uidelines, an aquatic system may still be at risk from the contaminated sediment. If the contaminated sediment were to be disturbed through flooding, bioturbation or changes in the water chemistry, these contaminants will desorb into the water column and as a result be detrimental to life forms in contact and dependent on that water source. Monitoring sediment has been a widespread initiative internationally and has led to the development of various sediment toxicity test methods, including different bioassays. This study focused on sediment bioassays such as the Phytotoxkit-F and Ostracodtoxkit-F, and the Diptera bioassay to assess the sediment quality of the Tweelopiespruit-Rietspruit-Bloubankspruit (TRB) river system in Gauteng, South Africa. This river is known to be impacted by acid mine drainage (AMD) since late August 2002. Exposure of the bioassays to river sediment from preselected sampling sites (Site 1, closest to the mine, to Site 6, furthest from the mine, and Site 7, the reference site) provided an eco-toxicological estimation of the acute toxicity emanating from contaminants in the sediment. Physico-chemical analyses revealed high concentrations of metals and other contaminants in the water and sediment. A general linear decrease in contaminant concentrations was observed from Site 1 to Site 6. The results from the bioassays displayed a similar trend, since there were greater sensitivities (mortalities and growth inhibition) to sediments sampled closer to the mine. Due to high levels of contamination in sediments, compared to the overlying water, and the potential impact on aquatic organisms, sediment toxicity monitoring should be a compulsory requirement for environmental studies in South Africa

The impact of a power plant discharge (Clinch River Plant, CRP, Carbo, Virginia) on resident snail populations was assessed. In 1988, snail absence below the plant, was attributed to plant discharges rather than naturally occurring habitat limitations. Habitat limitations for the two dominant snail species, Leptoxis praerosa and Pleurocera unciale were defined before power plant impact was assessed. Eleven physicochemical parameters (i.e., flow rate, substrate type, silt accumulation, depth, water chemistry and food biomass parameters) were measured at selected sites and compared to snail density. Flow rate, substrate type and periphyton biomass were the most influential parameters in determining Leptoxis density; while periphyton biomass was the most influential for Pleurocera. Cluster analysis also linked Leptoxis density with river structure and flow. Other variables linked to Pleurocera density were flow rate, river structure and silt. Although Leptoxis is most prolific in riffle/shoal areas and Pleurocera in slower riffle-pool interfaces, these two ‘species often coexist. This research suggests that habitat partitioning between these two species is influenced most by flow rate. Greatest density of Leptoxis occurred at flow rates of 20-30 cm/sec. Frequency of occurrence was greatest at 20-100 cm/sec. Pleurocera occurred most frequently at flow rates of 20-30 cm/sec with greatest density at 25-45 cm/sec. Measurements of impact of the CRP effluent (i.e., toxicity, metals {mainly copper} bioaccumulation in aufwuchs and snails, and cellulase enzyme activity impairment) were summarized by using zone delineation. Habitat parameters were measured below plant discharges and upstream, and compared with water column Cu, snail tissue Cu and aufwuchs Cu measurements. Habitat selection was strongly influenced by effluent but the role of waterborne metals concentration and habitat alterations (e.g. periphyton changes and bioconcentration) was unclear. Feeding studies were conducted to estimate impact of aufwuchs bioconcentration of metals on snails. Leptoxis significantly bioconcentrated Cu when fed aufwuchs containing 564 (±269) ug Cu/g in artificial stream feeding studies, but no cellulase impairments were seen in these studies. No foodborne bioconcentration was found from aufwuchs containing up to 20,000 (±18,400) ug Zn/L. These results suggest that though foodborne uptake of Cu may occur, water column Cu concentrations may have to be an order of magnitude higher for impairment to occur through injestion than through waterborne exposures. Acute and chronic effects of both whole effluent and Cu on Leptoxis were measured in laboratory and artificial stream exposures. The 96-hr LC₅₀ was 95% effluent (containing 148 ug Cu/L)in flow-through exposures, but in Static stirred exposures, 100% effluent (105 ug Cu/L)was not toxic. The lowest-observable effect concentration (LOEC)from 30-day exposures was 10% effluent (22 ug Cu/L) causing cellulase activity impairment (70% of control activity) and bioconcentration (300 ug Cu/g). Constituents of effluent other than Cu were believed to contribute to impairment effects since no impairment was found in 30-day CuSO₄ dosings of up to 25 ug Cu/L. The LOEC for Cu from 30-day CuSO₄ dosings ranged from 17-35 ug/L and the no-observed effect concentration (NOEC)was 12 ug Cu/L. The EPA water quality criteria concentration (17 ug Cu/L)was questionable for Leptoxis in long-term exposures (114-day), causing enzyme impairment and mortality. Chronically toxic conditions to Leptoxis occurred on the left side of the river for 0.7 km downstream of discharge, where the water column contained 42 ug Cu/L, while acutely toxic conditions occurred in the immediate mixing zone. Artificial stream impairment tests were substantiated in the river except in lower reaches of the impairment zone (left side of river, 0.7-0.9 km below cooling tower discharge), where snail absence was attributed to periphyton Cu bioconcentration (242 ug Cu/g). Functional recovery (of enzyme activity) was found at the next acceptable habitat downstream (Station 14A), so the area of impact extended 0.9 km downstream of the discharge on the left side of the river. It was concluded that zone delineation by simultaneously evaluating structural and functional aspects of environmental change is a better approach to impact assessment than approaches that only use functional measurements. / Ph. D.

M.Sc. (Aquatic Health) / Sediments can contain a variety of organic and inorganic contaminants. These contaminants accumulate, resulting in extremely high concentrations even once the overlying water concentrations are at or below acceptable water quality guidelines. Any changes in the physical parameters'of the overlying water can cause these pollutants to be released back into solution. Accumulated contaminants can be released at even higher concentrations than previously detected. In recent years, sediment contamination has highlighted the need to monitor these previously overlooked pollutant sources that have accumulated in aquatic ecosystems. South Africa does not currently have standardised methods to assess sediment toxicity. Although international methods exist, they are largely untested in South Africa and the organisms needed to conduct these tests are not readily available. Over the years numerous culture methods have been develop globally for culturing organism to be used for water and sediment toxicity tests. In South Africa, the focus has mainly been on culturing organisms for water. toxicity testing. Sediment toxicity testing with indigenous organism however, was not developed. Established international culture methods from the United States Environmental Protection Agency, the Organisation for Economic Cooperation and Development, and Environment Canada were taken into consideration when developing the laboratory culture method for two (2)of the selected organisms (Chironomus spp. & Hydra sp.) from this study. A preliminary culture method was also developed for the third selected organism, Melanoides tuberculata (gastropod). The organisms cultured in this study were selected based on their extent of contact with the substrate, ease of handling, availability, culture maintenance as well as their reproductive cycle. The Hydra, Chironomids and M. tuberculata cultures were successfully breeding under laboratory conditions and remained stable. The Chironomus sp. and M. tuberculata maintain contact with the sediment making them suitable as ecologically relevant organisms for use in whole sediment toxicity testing in South Africa.

by Tsui Tsz Ki, Martin. / Thesis (M.Phil.)--Chinese University of Hong Kong, 2002. / Includes bibliographical references (leaves 119-138). / Abstracts in English and Chinese. / Acknowledgements --- p.I / Abstract --- p.III / Table of Contents --- p.VII / List of Tables --- p.XII / List of Figures --- p.XIV / Abbreviations --- p.XVI / Chapter Chapter 1 --- General Introduction / Chapter 1.1 --- Research Background --- p.1 / Chapter 1.1.1 --- General description of glyphosate --- p.1 / Chapter 1.1.2 --- Physical and chemical properties of glyphosate --- p.2 / Chapter 1.1.3 --- Commercial formulations based on glyphosate --- p.3 / Chapter 1.1.4 --- Overview of ecotoxicological studies of glyphosate-based formulations --- p.4 / Chapter 1.1.4.1 --- Aquatic toxicity of glyphosate-based formulations --- p.4 / Chapter 1.1.4.2 --- Environmental fate of glyphosate-based formulations in waters --- p.12 / Chapter 1.1.5 --- Interaction of glyphosate and other substances --- p.14 / Chapter 1.2 --- Overview of Aquatic and Sediment Toxicology --- p.16 / Chapter 1.2.1 --- Aquatic toxicology --- p.16 / Chapter 1.2.2 --- Introduction to sediment toxicology --- p.19 / Chapter 1.3 --- "Significance, Outline and Objectives of the Present Study" --- p.20 / Chapter 1.3.1 --- Significance of the research --- p.20 / Chapter 1.3.2 --- Thesis outlines and research objectives --- p.22 / Chapter Chapter 2 --- Aquatic Toxicity of Glyphosate-based Herbicides to Different Organisms and the Effects of Environmental Factors / Chapter 2.1 --- Introduction --- p.25 / Chapter 2.2 --- Materials and Methods --- p.26 / Chapter 2.2.1 --- Test organisms --- p.26 / Chapter 2.2.2 --- Test chemicals --- p.27 / Chapter 2.2.3 --- Comparison between different organisms --- p.27 / Chapter 2.2.4 --- Environmental factors in modifying Roundup® toxicity --- p.30 / Chapter 2.2.5 --- Analysis of glyphosate concentration --- p.31 / Chapter 2.2.6 --- Validity of tests and statistical analyses --- p.32 / Chapter 2.3 --- Results --- p.32 / Chapter 2.3.1 --- Comparison between different groups of organisms --- p.32 / Chapter 2.3.2 --- Environmental factors in modifying Roundup® toxicity to C.dubia --- p.35 / Chapter 2.4 --- Discussion --- p.36 / Chapter 2.4.1 --- Toxicity of glyphosate to photo synthetic organisms --- p.36 / Chapter 2.4.2 --- pH-associated toxicity of glyphosate --- p.37 / Chapter 2.4.3 --- High potency of surfactant --- p.38 / Chapter 2.4.4 --- Effects of environmental factors on Roundup® toxicity --- p.38 / Chapter 2.5 --- Conclusions --- p.39 / Chapter Chapter 3 --- "Toxicity of Rodeo®, Roundup® Biactive and Roundup® to Water-column and Benthic Organisms and the Effect of Organic Carbon on Sediment Toxicity" / Chapter 3.1 --- Introduction --- p.41 / Chapter 3.2 --- Materials and Methods --- p.43 / Chapter 3.2.1 --- Test chemicals --- p.43 / Chapter 3.2.2 --- Test organisms --- p.43 / Chapter 3.2.3 --- Toxicities to water-column and benthic organisms --- p.44 / Chapter 3.2.4 --- Effect of sediment organic carbon --- p.45 / Chapter 3.2.5 --- Statistical analyses --- p.48 / Chapter 3.3 --- Results --- p.48 / Chapter 3.3.1 --- Toxicities to water-column and benthic organisms --- p.48 / Chapter 3.3.2 --- Effect of sediment organic carbon --- p.49 / Chapter 3.4 --- Discussion --- p.54 / Chapter 3.4.1 --- Different sensitivities between water-column and bethic animals --- p.54 / Chapter 3.4.2 --- Relative toxicities of three herbicides --- p.56 / Chapter 3.4.3 --- Route of exposure of herbicides in sediment to organisms --- p.57 / Chapter 3.4.4 --- Sediment toxicity of glyphosate-based formulations --- p.58 / Chapter 3.4.5 --- Effect of organic carbon on partitioning and toxicity --- p.60 / Chapter 3.5 --- Conclusions --- p.61 / Chapter Chapter 4 --- Joint Toxicity of Glyphosate and Several Selected Environmental Pollutants to Ceriodaphnia dubia / Chapter 4.1 --- Introduction --- p.63 / Chapter 4.2 --- Materials and Methods --- p.65 / Chapter 4.2.1 --- Test organisms and toxicity tests --- p.65 / Chapter 4.2.2 --- Test chemicals --- p.66 / Chapter 4.2.3 --- Experiment I: Joint acute toxicity of Roundup® and nine toxicants --- p.66 / Chapter 4.2.4 --- Experiment II： Effect of IPA salt of glyphosate alone at EEC on toxicities of heavy metals --- p.67 / Chapter 4.2.5 --- Basic water properties and chemical analyses --- p.69 / Chapter 4.2.6 --- Statistical analyses --- p.70 / Chapter 4.3 --- Results --- p.70 / Chapter 4.3.1 --- General conditions and recovery for spiked chemicals --- p.70 / Chapter 4.3.2 --- Experiment I: Joint acute toxicity of Roundup® and nine toxicants --- p.71 / Chapter 4.3.3 --- Experiment II: Effect of IPA salt of glyphosate alone at EEC on toxicities of heavy metals --- p.73 / Chapter 4.4 --- Discussion --- p.75 / Chapter 4.4.1 --- Interactions of Roundup® and other toxicants --- p.75 / Chapter 4.4.2 --- Joint toxicity of dissimilar chemicals --- p.77 / Chapter 4.4.3 --- Complexation of glyphosate with metals interactions between liquid/solid phases --- p.79 / Chapter 4.5 --- Conclusions --- p.83 / Chapter Chapter 5 --- Environmental Fate of Glyphosate and its Nontarget Impact: a Case Study in Hong Kong / Chapter 5.1 --- Introduction --- p.85 / Chapter 5.2 --- Materials and Methods --- p.87 / Chapter 5.2.1 --- Description of study sites --- p.87 / Chapter 5.2.2 --- Physicochemical characteristics of different matrices --- p.88 / Chapter 5.2.3 --- Continuous weather monitoring --- p.89 / Chapter 5.2.4 --- Herbicide applications --- p.89 / Chapter 5.2.5 --- Experimental designs --- p.90 / Chapter 5.2.5.1 --- Estuarine enclosure experiment --- p.90 / Chapter 5.2.5.2 --- Freshwater pond experiment --- p.92 / Chapter 5.2.6 --- Schedule of sample collection and sample storage --- p.92 / Chapter 5.2.7 --- Sample preparation --- p.94 / Chapter 5.2.7.1 --- Water samples --- p.94 / Chapter 5.2.7.2 --- Sediment samples --- p.94 / Chapter 5.2.8 --- Sample determination --- p.95 / Chapter 5.2.8.1 --- Pre-column derivatization --- p.95 / Chapter 5.2.8.2 --- High performance liquid chromatography analyses --- p.95 / Chapter 5.2.8.3 --- Calibration of glyphosate and AMPA --- p.95 / Chapter 5.2.8.4 --- Recovery of glyphosate in spiked samples --- p.96 / Chapter 5.2.9 --- Statistical analyses --- p.96 / Chapter 5.3 --- Results --- p.96 / Chapter 5.3.1 --- Site characteristics --- p.96 / Chapter 5.3.2 --- Weather conditions during herbicide application --- p.99 / Chapter 5.3.3 --- Chemical analyses --- p.100 / Chapter 5.3.4 --- In-situ toxicity tests --- p.104 / Chapter 5.4 --- Discussion --- p.106 / Chapter 5.4.1 --- Site-specific factor affecting the environmental fate --- p.106 / Chapter 5.4.1 --- Site-specific factor affecting the environmental fate of glyphosate --- p.106 / Chapter 5.4.2 --- Glyphosate in water and sediment --- p.106 / Chapter 5.4.3 --- Homogeneity of glyphosate in surface water and sediment --- p.109 / Chapter 5.4.4 --- Effect of weather conditions on environmental fate of glyphosate --- p.109 / Chapter 5.4.5 --- Biological impact of Roundup® --- p.110 / Chapter 5.5 --- Conclusions --- p.112 / Chapter Chapter 6 --- General Conclusions --- p.113 / References --- p.119