Use of pesticides has been linked to health effects among exposed workers. Organophosphate and pyrethroid pesticides are commonly used to control mosquito-borne diseases in Malaysia. This project aimed to estimate workers' lifetime exposure to pesticides and to examine the relationship between that exposure and health-related quality of life and neurobehavioural performances. A total of 158 workers who had regular contact with pesticides and 176 officebased workers were recruited to the study. Information on past exposure was collected through questionnaire and occupational history interview to help reconstruct workers' historical exposures. Personal inhalation and dermal exposure measurement were carried out to evaluate current pesticide exposure. Subjective inhalation and dermal models were used to allow the estimation of combined pesticide intake for each worker. Neurobehavioural performance was assessed using CANTAB® computerized tests. Total lifetime pesticides intake for exposed workers ranged from 0.006 g to 12,800 g (median (IQR) = 379 g (131, 794)). Estimated dermal exposure accounted for the majority of total lifetime intake of pesticides (median (IQR) = 369 g (128, 772)). After adjusting for age, education, smoking and BMI, exposure to pesticides was associated with lower physical health scores. All of the neurobehavioural performance test scores, with the exception of Reaction Time (RT) and Pattern Recognition Memory (PRM) tests, showed significant differences in relation to total lifetime pesticides intake after adjusting for age, education and smoking. The majority of pesticide-exposed workers indicated a positive awareness about pesticide risk. However, this awareness was not reflected to their selfprotective behaviours such as wearing PPE. Findings from this study suggest that lifetime pesticide intake is associated with physical health and cognitive impairment. It is not clear if this association is causal. Occupational hygiene control measures should focus on reducing the amount of pesticides workers get on their skin due to the high percentage of total intake arising from dermal exposure.

New cobalt (13, 16 19 and 22), manganese (14, 17, 20 and 23) and iron (15, 18, 21 and 24)phthalocyanine complexes were synthesized and characterized. The UV-Vis spectral properties of the complexes were typical of the nature of central metal and position of substituent on the Pc ligand. Their electrochemical behaviors were signatures of the central metals, with varying influences of the nature and position of substituents. Nanocomposite of complex 18 and single walled carbon nanotubes (SWCNTs) (SWCNT-18)was fabricated. Formation of this nano-composite was confirmed by infrared (IR)spectroscopy, X-ray diffraction (XRD) spectroscopy and transmission electron microscopy (TEM). Self-assembled monolayers (SAMs) of SWCNT-18, complexes 13-15, and 20 were electropolymerized on glassy carbon electrodes (GCE). Complex 14 was also electrodeposited on GCE. Surface properties of the SAMs were consistent with the molecular feature of the substituent and the nature of central metal in the adsorbed species, while those of the MnPc modified GCEs were dependent on point of substitution and number of substituent. The SAM-modified gold electrodes were used for the electrocatalytic oxidation of the carbamate insecticide, carbofuran. Amplification of the current signal of the insecticide, at more energetically feasible oxidation potentials, on the SAM-modified gold electrodes, relative to bare gold electrode,justified electrocatalysis. There was enhanced sensitivity (attributed to the presence of SWCNT) of the SWCNT-18-SAM-modified gold electrode towards carbofuran, relative to the signals observed on the other SAMs. Current response of the insecticide,bendiocarb, was also intensified, at more favorable oxidation potentials, on the MnPc (14 and 17) modified GCEs, relative to the response on bare GCE, substantiating electrocatalysis. Also, catalysis of the oxidation of the herbicide, bentazon, was observed on polymeric film of complex 20. The current response of the herbicide on this film was better than that observed on bare GCE. Electrocatalysis of the analytes, on the respective modified electrodes, occurred via closely related mechanisms.

Two possible ways in which fish may acclimate to prolonged exposure· to sublethal levels of endosulfan were investigated: induction of the hepatic monooxygenase system and changes in haematology. These studies also involved an examination of the ultrastructure of liver and gill tissue. Endosulfan caused none of the characteristic phenobarbital-type inductive effects on the liver of Oreochromis mossambicus. There was no increase in cytochrome P-450 levels, microsomal protein or hepatosomatic index. The reasons for the lack of induction are discussed. The effect of endosulfan on the following haematological parameters was determined: haemoglobin, erythrocyte count, microhaematocrit, mean erythrocyte volume and mean erythrocyte haemoglobin concentration. The only effect was an increase in erythrocyte count. The value of changes in haematological parameters as indicators of pollutioninduced anemia in the field is discussed. No changes in gill ultrastructure were noted although electron micrographs of liver tissue showed lesions in hepatocytes. The diagnostic value of pollution-induced pathological changes on cell ultrastructure are discussed. Recommendations are made with regard to future large scale application of pesticides on or near large water bodies

A comprehensive literature review is presented concerning pesticides; in particular the organochlorine insecticides, DDT and dieldrin, and their role in the pollution of water resources. The results of a laboratory study on the removal of DDT and dieldrin (HEOD) by adsorption onto a clay of the montmorillonite type (bentonite) are presented. For an initial DDT concentration of 100 μgm/l, the addition of bentonite at concentrations of 1.0 gm/l and 10.0 gm/l results in the removal of about 60 and 72 per cent, respectively, of the insecticide. For an initial HEOD concentration of 100 μgm/1, the addition of bentonite at concentrations of 1.0 gm/l and 10.0 gm/l brings about the removal of about 15 and 30 per cent, respectively, of this insecticide. The results of a laboratory study on the desorption of DDT and HEOD from the bentonite are presented. Both insecticides are desorbed from the clay, the HEOD being desorbed to the greater extent and the DDT desorption being quite minimal. The results of a further laboratory study conducted to ascertain the ability of bentonite clay to remove, by adsorption, insecticides from solution while settling through a quiescent water body are presented. Bentonite at concentrations of 1.0, 5.0, and 10.0 gm/l removes about 44, 48, and 54 per cent, respectively, of DDT from the quiescent water body initially containing 100 μgm/1 DDT. Bentonite at concentrations of 1.0, 5.0 and 10.0 gm/l removes about 14, 23, and 30 per cent, respectively, of the HEOD from the quiescent water body initially containing 100 μgm/1 HEOD. The results of an inorganic blanketing study indicates that the addition of a layer of sand over DDT and HEOD contaminated benthic deposits will block, somewhat, the desorption of these insecticides into the overlying waters. / Applied Science, Faculty of / Civil Engineering, Department of / Graduate

This investigation was limited to the preparation of substituted phenoxyacetic acids and related compounds. The types of substances prepared for testing can, in general, be placed in three groups. These are: aryloxyacetic acids, arylmercaptoacetic acids, and those acids containing the thiophene nucleus.

Pesticides are the substances designed for destroying, preventing and controlling of pests and protection of plants. Their wide usage in agriculture causes contamination of ground, surface and drinking water, because wastewater treatment plants are not able to remove them. Mostly used pesticides are triazine based pesticides. However their usage is worldwide reduced because of their negative influences on human health and contamination of environment especially with their metabolites, about their toxicity are no information. A method for determination of triazine pesticides atrazine, cyanazine, propazine, simazine, terbuthylazine and their metabolites hydroxytrazine, desethylatrazine, desisopropylatrazine, hydroxyterbuthylazine a desethylterbuthylazine was developed and validated in this diploma work. The determination was realized by LC-MS/MS with electrospray ionization. LOD ranged between 0.5-3.2 pg/ml and LOQ between 1.5-9.6 pg/ml. A test of stability of the maternal substances of these pesticides was performed, in which temperature was found to have the biggest influence on their degradation. A monitoring of the presence of triazine pesticides and their metabolites in water was carried out in Czech Republic. Low concentrations of the maternal substances in surface water and ground water were...

Nominal Rates of Protection (NPR) were calculated to quantify the degree of pesticide subsidy in Ecuador from 1991 to 1996. Equilibrium exchange rates were computed first to determine the indirect and total NPR's in addition to the direct NPR's. The computed equilibrium exchange rates from 1987 to 1996 indicated a decreasing trend in Sucre overvaluation. The direct NPR's indicated a small tax on pesticides due to a tariff and customs tax, and the indirect NPR's indicated a decreasing trend of subsidization due to the reduction in Sucre overvaluation. In sum, total NPR's indicated that the subsidy on pesticides has decreased substantially. A demand function for pesticides was estimated to quantify the effect of price distortions on pesticide demand. Due to the limited degrees of freedom, a statistically significant function was not obtained. However, pesticide price, agricultural credit, and overvaluation of the Sucre were statistically significant in influencing pesticide demand. Policy implications were drawn based on empirical results and background information. Since the agricultural profitability of small farms producing outputs for domestic consumption is most affected by the current economic liberalization, the Ecuadoran government may need to find a means for supporting the profitability of these farms to protect national agricultural productivity. Policies that aid these farmers in the adoption of inexpensive integrated pest management (IPM) technologies would help achieve this end, while reducing the environmental and health problems caused by pesticide use. / Master of Science

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