No description available.

Nutrients are of critical concern in water quality assessment. The development of empirical models to estimate mean nutrient concentrations, based on satellite derived land use, could aid water resource managers. Models using land use acreages outperformed those using percentages, and discrete urban land uses were superior to lumped urban. Regressions of the combinations of two, three and four of the eight possible land use variables were investigated. Sensitivity analyses, with one stream deleted each series, identified robust combinations of variables at each level. Although uncertainty exists regarding the final regression coefficients, five of the six actual measured nitrate and total phosphorus mean concentrations were within the 95 percent confidence limits.

Water is a prerequisite for life on our planet. Due to climate change and pollution, water availability for agricultural production, industry and households is increasingly put at risk. With agriculture being the largest water user as well as polluter worldwide, we estimate anthropogenic nitrogen and phosphorus emissions to fresh water related to global crop production at a spatial resolution level of 5 by 5 arc min and calculate the grey water footprints (GWF) related to EU-27's crop production. A multiregional input-output model is used to trace the the GWF embodied in the final consumption of crop products by the EU-27. The total GWF related to crop production in the EU-27 in 2007 was 1 × 1012 m3/year. Spain contributed about 40% to this total. Production of cereals (wheat, rice and other cereals) take the largest share, accounting for 30% of the GWF, followed by fruits (17%), vegetables (14%), and oil crops (13%). The total agricultural GWF of the EU-27 related to crop consumption was 1830 billion m3/year, which is 3700 m3/year per capita on average. Overall, the EU-27 was able to externalize about 41% of the GWF to the rest of the world through imports of crop products.

Contamination of recreational and shellfish waters with fecal pollution is a major water quality issue with associated economic impacts and human health risks. Reliable fecal source identification and rapid, quantitative analyses are essential components of risk assessment. Enteric bacteria that are endemic to specific hosts have a potential role as public health indicators of fecal pollution. Building on previous work to discriminate ruminant and human fecal contamination, we cloned class Bacteroidetes 16S rRNA genes from pig, elk, dog, cat, and seagull fecal DNAs. Unique restriction patterns were identified among clones from each of the host species using Terminal Restriction Fragment Length Polymorphisms (T-RFLP). Clones exhibiting unique patterns were sequenced and analyzed phylogenetically, along with human, horse, and cattle sequences recovered from previous work. The analysis revealed both endemic and cosmopolitan (global) host distributions. The sequence data were used to identify host-specific genetic markers for pig and horse feces, and to design PCR primers that identify these sources of fecal pollution in water. There was a high degree of sequence overlap among the fecal Bacteroidetes of wild and domestic ruminants, and among human, domestic pet, and seagull Bacteroidetes. We compared fecal Bacteroidetes rRNA genes from these hosts using subtractive hybridization, a method that identifies differences between closely related genomes or gene sequences. A Bacteroidetes rDNA marker that distinguishes elk and cow feces was identified, as well as a host-specific marker for dog fecal Bacteroidetes. The four newly designed PCR primers were tested for specificity and sensitivity, and the dog primer was successfully used, along with the human and ruminant-specific primers, in a collaborative study comparing fecal source tracking methods. We also developed a real time Taq nuclease assay for quantification of fecal Bacteroidetes 16S rDNA, and compared it with an EPA-approved enumeration method for the current standard public health indicator, Escherichia coli, in serial dilutions of sewage primary influent. There was a strong, positive correlation between the methods, and the Taq nuclease assay was sensitive and much more rapid than the E. coli assay. PCR source identification and enumeration of fecal Bacteroidetes 16S rDNA show promise for application in a health risk-based analysis of fecal pollution. / Graduation date: 2005

The extent of agricultural drainage has created concern for its potential undesirable effects on surface water quality. Land applications of liquid manure on tile drain fields have the potential to transport solutes and bacteria to the drains following precipitation or irrigation events and many times are directly sent to a surface water body, and have been documented as a source of contamination of surface waters. This study determined the potential for and magnitude of E. coli and solute migration to tile drains through the soil profile. Water from subsurface drains was analyzed for chemical and bacterial composition following tracer applications. Two sites were selected for the study to determine transport at large (field) and small (plot) scales. At the large-scale site, both tracers, bacteria (E. coli and Total Coliform) and Amino-G (a conservative tracer), were used to monitor the speed of transport from the surface to the tile drain following liquid manure applications, tracer applications and additionally precipitation events. The concentrations of E. coli were monitored every hour for 76 days during the spring. Both tracers, bacteria and Amino-G, were detected in the tile drainage shortly after precipitation events. The peak concentration of E. coli was observed to be 1.2 x 10⁶ CFU/l00mL. These elevated concentrations of E. coli might be attributed to the characteristics of the soil, high organic matter and well-structured clay soils. Both the rapid breakthrough of tracer to the tile drain and the peaks of tile water temperature during precipitation events provided evidence of macropore flow. Antecedent soil moisture and warmer temperatures appeared to provide ideal conditions for bacteria growth. The small-scale study site was selected for a more focused study. The purpose of this site was to quantify more accurately the percent mass of surface applied tracer that was transported to the tile drain, allowing mass balance calculations. Experiments were conducted during the summer to control the rate and total amount of irrigation. Amino-G readings were taken every 10 seconds for 125 hours of continuous irrigation. Tracer applications were conducted at runoff and non-runoff conditions. Both types of tracer applications had Amino-G breakthrough in less than 10 minutes after initiation of irrigation. Tracer applied at runoff rates resulted in 4 to 17 times more total tracer mass migrating to the tile drain than when applied at non-runoff rates. The total mass of Amino-G migrating to the tile drain during non-runoff conditions depended on the total volume of applied tracer, regardless of the tracer concentration. For an application of 5.6 mm at 12 mg/L, 5.7% of the total applied tracer migrated to the tile drain, whereas for an application of 1.9 mm at 27.7 mg/L only 2.8% of the total applied tracer migrated to the tile drain. Tile flow response to irrigation experiments appeared to be governed by soil moisture. Lysimeter samples were taken continuously every 4-8 hours until the 94th hour after tracer application. Tile water concentrations were consistently greater than concentrations found in the deeper suction lysimeters at corresponding times, providing further evidence of preferential flow. E. coli transported through the soil and into the drains were demonstrated to be event-driven by precipitation events and irrigation events. In addition, the characteristics of this type of soil - the high clay content, the well-defined structure, the high level of organic matter and rich biological activity has been known to enhance the preferential pathways and transport processes in the soil profile, resulting in rapid transport of surface applied solutes and effluents to tile drains. / Graduation date: 2003

Graduation date: 1997

Interactions between cyanobacteria and herbivorous grazers play an important role in mediating the responses of freshwater phytoplankton assemblages to nutrient enrichment and top-down manipulation. Negative consequences associated with these interactions include dangerous blooms of harmful blue-green algae that have been implicated in the sickness and death of fishes, livestock, and, in extreme cases, humans. Frequently cited mechanisms influencing the interactions between grazers and cyanobacteria include cyanobacterial toxicity and morphology. To tease apart the importance of these mechanisms, I used meta-analysis to quantitatively synthesize the available literature on this topic. In addition, I conducted several experiments using novel techniques to determine the effect that cyanobacterial secondary metabolites from the bloom-forming cyanobacterium,

Concentrations of 17 organochlorine and 14 organophosphorus pesticides were measured in 27 ground and 11 surface water samples collected from a heavily agricultural area, Kumluca, in spring and fall seasons of 2005. The samples were preconcentrated by Solid Phase Extraction. GC-ECD and GC-NPD systems were used for quantitative determination of organochlorine and organophosphorus pesticides respectively. The quality check/quality assurance tests were performed by the analysis of field and laboratory blanks, standard reference materials, spiked control and sample matrices, surrogate standards, sampling and analysis replicates. It is observed that, sample matrix lowers average percent recoveries from 89% to 76%. The uncertainties of measurements were calculated to determine major factors affecting the analysis results. It was observed that uncertainty arising from extraction procedure was generally the highest. The most commonly observed pesticide was endosulfan (70%) and chlorpyriphos (53%) for organophosphorus and organochlorine pesticides. The highest average concentration was observed for heptachlor (26 ng/L) and fenamiphos (184 ng/L). Generally pesticides were detected more often in surface waters, where the concentrations were also higher. The concentrations of organophosphorus pesticides in spring, and organochlorine pesticides in fall season were higher. The high occurrences and detection of degradation products of chlorinated pesticides clearly indicate their intense use before 1980s. It is shown that, in Kumluca environment, degradation of these pesticides mostly occurs in surface waters. It is observed that agricultural activities affect water quality in the region. The total concentration limit (500ng/L) was exceeded for 27% of surface and 14% of ground water samples, at least once in both seasons. The legal limit for a single pesticide (100ng/L) was exceeded by 32 % of surface, 24 % of ground water samples.

In this study, it is aimed to develop a database on Seyhan River Basin / and an environmental pollution index for the middle section of Seyhan Basin by combining different pollution indices such as water, and air. Water and air pollution indices are developed for the selected quality monitoring stations and the selected years. Water pollution index is calculated by using the method suggested by National Sanitation Foundation of United States, and air pollution index is developed according to the modified Environmental Protection Agency&rsquo / s air pollution index. As aggregation method, weighted arithmetic mean function is used for development of indices. After development of separate water and air pollution indices, environmental pollution index is developed for the year 2008 by two aggregation methods, one based on linguistic interpretation and the other again on weighted arithmetic mean function. The water pollution index for the middle section of the basin is determined as &ldquo / good&rdquo / , and air pollution index as &ldquo / low pollution&rdquo / . According to calculated water and air pollution indices, environmental pollution index is calculated with two methods and obtained the index equal to 4, which is classified as &ldquo / good&rdquo / . Although, both of the methods give same result in development of environmental pollution index, the second method based on weighted arithmetic mean function concluded to be more user friendly.

Thesis (Ph. D.)--Joint Program in Oceanography (Massachusetts Institute of Technology, Dept. of Earth, Atmospheric, and Planetary Sciences; and the Woods Hole Oceanographic Institution), 2002. / Includes bibliographical references.