Thesis (M.S.)--California Polytechnic State University, 2010. / Title from PDF title page; viewed on June 10, 2010. Major professor: Lynn E. Moody, Ph.D. "Presented to the faculty of California Polytechnic State University, San Luis Obispo." "In partial fulfillment of the requirements for the degree [of] Master of Science in Agriculture, with a Specialization in: Soil Science." "April 2010." Includes bibliographical references (p. 48-51).

Agricultural nonpoint source pollution is recognised as a major cause of water pollution. The characteristics of nonpoint source pollution suggest that an efficient approach should focus on a source control and hence land-use management. Recently, the concept of Payments for Ecosystem Services (PES) has been advanced as an efficient market-based approach to protect in-stream water quality, while simultaneously supporting agriculture. Farmers can be rewarded for the adoption of certain ‘Best Management Practices’ (BMPs) in farming systems. But little is known about the adoption of BMPs in the context of Thai agriculture. This thesis examines the adoption of twelve BMPs on citrus farms in the Ping river basin in northern Thailand. In the context of potential PES development, three studies were undertaken using frameworks from economics and psychology. The first study used a bottom-up engineering approach to estimate economic costs of twelve BMPs at the farm-scale. The total annualised costs, including installation, maintenance, and land opportunity costs of each BMP were compared. The results indicated that land opportunity cost was the largest proportion of total costs. These estimates provided a basis for discussion on how the farmers’ perception of cost may influence their stated adoption intention. The second study used the Theory of Planned Behaviour (TPB), to investigate farmers’ intentions on adoption of twelve BMPs. A survey of 218 citrus farmers was undertaken in the application. Descriptive statistics and frequency of BMP selection were presented. The results showed that soil analysis was the most preferred BMP. A graphical analysis of other preferred measures suggested that these were not always consistent with the known cost information derived (above) and thus farmers’ perceived costs might not be the most important factor influencing adoption decisions. Further analysis based on TPB investigated other factors thought to be significant in farmers’ decision-making. Other potential external and psychological factors influencing adoption were investigated using a multinomial logistic model. The results indicated that the probability of adopting BMPs was associated with other psychological factors and external factors, rather than perceived costs. The significant psychological factors were farmers’ attitudes towards consumers and perception about farm returns, while the significant external factors were, for example, access to information and contribution of family labour to farm workload. The third study was based on the application of Q-Methodology, and aimed to obtain a deeper understanding of farmers’ perception towards BMPs. Seventy two participants were purposively selected from the 218 TPB observations. The results revealed four distinctive farmer groups holding different perceptions towards BMPs. The four groups were conservationist, traditionalist, disinterested, and risk-averse. These provided a specific segmentation to guide policy towards influencing attitudes and behaviours. The results suggested that farmers were not motivated solely by a profit maximisation goal. Overall, key findings from these three studies revealed some fundamental requirements for developing a water-related PES programme. These were: i) factors affecting eligibility to participate; ii) factors affecting desire to participate; and iii) factors affecting ability to participate. This information provided the basis for a set of recommendations addressing the development of the water-related PES programme in the Ping river basin.

New methodologies have been developed for the determination of organotin and organolead compounds in environmental samples. Several high performance liquid chromatographic separations of organotin compounds have been tested and the best system (cation-exchange chromatography with methanol and a citrate buffer) employed for the determination of tributyltin (TBT), triphenyltin (TPhT), dibutyltin (DBT) and monobutyltin (MBT) in environmental samples. The coupling between high performance liquid chromatography (HPLQ and the inductively coupled plasma-mass spectrometer (ICP-MS) for this application has been modified to yield limits of detection of 0.44,0.26,1.4 and 0.23 ng. g-' as Sri for TBT, TPhT, DBT and MBT respectively. Different extraction procedures have been tested for the determination of organotin species in samples of environmental interest, such as sediments and biological materials. The values obtained for TBT, TPhT and DBT in the analysis of a mussel candidate reference material, CRM 477, have been incorporated in the certification campaign of this material. A liquid chromatographic separation for trimethyllead (TML) and triethyllead (TEL) has also been developed. Artificial rain water has been analysed for TML. The system proved to be valid for the determination of TML in this sample, even in the presence of high amounts of inorganic lead. Finally, isotope dilution analysis (IDA) was incorporated in the method. Tributyltin iodide (TBTI) and trimethyllead chloride (TMLCI), isotopically enriched in "Sn and "Pb, respectively, were synthesised. The mussel tissue CRM 477 was analysed with IDA-HPLC-ICPMS for TBT. As for the analysis without isotope dilution, the result obtained was incorporated in the certification campaign. The analysis with this methodology gave a better precision in the overall determination than external calibration analysis. Artificial rain water, at two different concentration levels, was analysed for TML with IDA-HPLC-ICP-MS. Better precision and accuracy was obtained for the analysis of this material with this method than when external calibration procedures were employed. IDA-HPLC-ICP-MS has proved to be a valid technique for the analysis of environmental samples. The technique simplifies the procedure, compensates for different sources of variability and, thus, the overall precision obtained in the analysis is improved compared to other calibration techniques.

Dyestuffs are widely used industrial chemicals, yet surprisingly little is known about their fate in the environment. The potential modes of transformation and removal of reactive dyes in treatment and in the environment are principally through anaerobic and aerobic biodegradation and photodegradation. The research herein describes the use of LC-MS analysis with laboratory simulations to develop a better understanding of the occurrence and fate of reactive dyes and their degradation products in the aquatic environment. One reason for the lack of information on the environmental fate of reactive dyes has been the paucity of robust analytical methods suitable for the determination of dyes in aqueous samples. Robust analytical methods were optimised to provide LC-MS and MSMS identification of degradation products. Additionally, interpretation of the MSMS spectra of known reactive dyes provided novel characteristic fragment ions indicative of the triazine reactive group of reactive dyes . Fibre reactive dyes are designed to have a degree of photostability and therefore their photodegradation behaviour has not been widely investigated. Little is known of their stability to daylight over prolonged periods of irradiation in dilute aqueous solutions and in the presence of humic substances. The kinetics of photodegradation of an anthraquinone dye (Reactive Blue H4R) and azo dye (Reactive Yellow P5G) were evaluated. The former underwent rapid and extensive degradation 01/2 1.5 h). The major products formed were identified using LC-MSMS and a photodegradation pathway proposed. By comparison, the photodegradation of the azo dye was significantly slower, 01/2 30 h). The addition of humic substancesa ppearedt o have little effect on the rate of photodegradationu nder the conditions used. The reduction of azo dyes under anaerobic treatment has been extensively studied, but the subsequent fate of the initial reduction products when exposed to air are not understood. Three relatively simple azo dyes, Amaranth, Sunset Yellow and Naphthol Blue-Black, were reduced and their autoxidation products identified by LC-MS. These were subsequently used to predict the autoxidation products of a more complex azo reactive dye: Reactive Red 3.1. Additionally, a persistent degradation product from the anaerobicaerobic treatment of Reactive Red 3.1 was identified from LC-MS data. Azo reactive dyes are generally regarded as being resistant to aerobic degradation and there are few published data regarding degradation pathways for reactive anthraquinone dyes. Pure cultures of Pseudomonas docunhae, A 9046 and A texaco and mixed bacterial consortia (semi-continuous activated sludge, SCAS) aerobic degradation of azo and anthraquinone reactive dyes was studied. Two azo dyes were degraded by pure cultures of A docunhae and A 9046, suggesting that azo dyes can be aerobically degraded given favourable conditions. The antraquinone dye was extensively degraded by SCAS and pure culture biodegradation. Metabolites were identified by LC-MS and a degradation pathway proposed.

This thesis describes a novel application of an artificial neural network and links together the two diverse disciplines of electroanalytical chemistry and information sciences. The artificial neural network is used to process data obtained from a Differential Pulse Anodic Stripping (DPAS) electroanalytical scan and produces as an output, predictions of lead concentration in samples where the concentration is less than 100 parts per billion. A comparative study of several post analysis processing techniques is presented, both traditional and neural. Through this it is demonstrated that by using a neural network, both the accuracy and the precision of the concentration predictions are increased by a factor of approximately two, over those obtained using a traditional, peak height calibration curve method. Statistical justification for these findings is provided Furthermore it is shown that, by post processing with a neural network, good quantitative predictions of heavy metal concentration may be made from instrument responses so poor that, if using tradition methods of calibration, the analytical scan would have had to be repeated. As part of the research the author has designed and built a complete computer controlled analytical instrument which provides output both to a graphical display and to the neural network. This instrument, which is fully described in the text, is operated via a mouse driven user interface written by the author.

Thesis (PhD. (Applied Science))--University of Pretoria, 2001. / Summaries in Afrikaans and English.

Thesis (M.S.)--West Virginia University, 2005 / Title from document title page. Document formatted into pages; contains vi, 113 p. : ill. (some col.), maps (some col.). Includes abstract. Includes bibliographical references (p. 107-113).

Thesis (M. Sc.)--University of Hong Kong, 1996. / Includes bibliographical references (leaf 87-94).

Thesis (M.S.)--Oregon State University, 2011. / Printout. Includes bibliographical references (leaves 69-74). Also available on the World Wide Web.

Provo Bay of Utah Lake, Utah, receives the effluents from farms, industry, and three cities. In order to determine the effects of these effluents, eleven stations were established throughout the Bay. At weekly intervals from June 19 to October 26, 1970, and monthly thereafter until March, 1971, the water at these stations was sampled for dissolved oxygen (DO}, carbon dioxide (CO2), turbidity, pH, phosphates, nitrates, biochemical oxygen demand (BOD) and coliform bacteria. Due to intense algal blooms, the quality of the water changes as it passes through Provo Bay. Average values for the inflow, mid-Bay, and point of discharge respectively during the summer are as follows: DO, 5.4--10.2--6.9 mg/l; CO2, 38--0--6 mg/l; turbidity, 19--80--57 Jackson Turbidity Units; pH, 7. 5--9. 0--7. 2; phosphates, 3. 62--0. 94--0.15 mg/l; nitrates, 0.71--0.08--0.00 mg/l; BOD, 17--27--9 mg/l; and coliforms, 31,000--31--0/100 ml. These results indicate that during the summer Provo Bay is acting as a tertiary treatment pond for the effluents which it receives.