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The thesis presents a series of principles, similar to those developed by the Organisation for Economic Co-operation and Development in relation to policy oriented indicators, intended to codify best-practice with regards to the design of pesticide risk indicators for use by farmers. Development of these principles was based upon extensive reviews of the literature concerning the potential exposure to and impacts of pesticides on non-target organisms and the relative merits and limitations of different methodological approaches, discussions with farmers concerning the suitability of different approaches to risk indicators and experimental assessments of indicator performance. These assessments took the form of a three-year field trial examining the impact of different levels of pesticide input upon non-target arthropods and several smaller trials that compared the performance of different insecticides and investigated the effect of differences in pesticide dose on non-target arthropods. The data were then compared with the theoretical results generated by a number of different risk indicators. The thesis also identifies a number of barriers to the implementation of these principles in the form of new pesticide risk indicators. These include restrictions on the range of non-target organisms and potential effects for which high quality data is available and the methodological difficulties associated with the incorporation of sublethal, indirect and ecosystem-level effects into risk indicators. Improvements in the validation of pesticide risk indicators that enable objective evaluations of indicator performance to be made are also required.

I. An analogue of the herbicide atrazine was synthesised and conjugated to carrier proteins for rodent immunisation and monoclonal antibody screening. II. Monoclonal antibodies from hybridoma clone 1G18 specific for the herbicide atrazine were successfully isolated. A suitable ELISA system was optimised and the binding capability and cross reactivity of these antibodies was found to be broadly similar to two other anti-atrazine monoclonal antibodies that were acquired externally. III. The antibody variable region domains of hybridoma 4063-21-1 were cloned and fully sequenced. The variable region domains of hybridoma AM1B5.1 were cloned and partially sequenced. IV. The variable region domains of hybridoma 4063-21-1 were sub-cloned into an expression plasmid and fully functional antibody fragments, specific for the herbicide atrazine, were obtained from <I>E. coli</I> fermentations. The recombinant antibody bound antigen with a binding capability that was 10% that of the whole murine antibody. V. The best yields of anti-atrazine antibody fragment were obtained from fermentations in buffered medium when the fermentation broth pH was maintained above pH 6.0. The recombinant antibody was purified by immobilised metal chelate affinity chromatography and the purified antibody fragment was found to bind antigen 10% as well as the crude recombinant antibody.

Graduation date: 1997

Thesis (M.S.)--Ohio State University, 1984. / Includes bibliographical references (leaves 129-130). Available online via OhioLINK's ETD Center