Environmental fate and exposure assessment of triphenyltin and its degradation products in soil has been studied by using both chemical and microbiological methods together. For the chemical method, phenyltin compounds were derivatised by ethylation with NaBEt₄ before injection into GC-MS, and analysed under selected ion monitoring (SIM) mode. the extraction recovery of phenyltin components (TPhT and DPhT) in soil was greater than 85%. The detection limits of MPhT, DPhT and TPhT in aqueous solutions were found to be 0.2, 0.2 and 0.3 ng as Sn, respectively which gave the limit of determination for the method as 0.01 μg g^-1 for both phenyltins in soils and sediments and butyltin in sediments. The <I>in-situ</I> ethylation was found to be one of the most powerful techniques for organotins in sediments as it is rapid, and reliable and no suppression by any organic content was found. The pH values of test solutions were found to affect the toxicity of phenyltin compounds to microbial biosensors as these factors may influence the hydrophobicity of the compounds. The toxicity order of TPhT, DPhT and MPhT to two luminescent bacterial biosensors was found to be different from that of the Microtox assay. DPhT was found to be the least toxic phenyltin compound to all biosensors while MPhT was found less toxic than TPhT when using <I>lux</I>-marked <I>P. fluorescens</I>, TPhT was found to be more toxic in aqueous solution than in soil extract, while the toxicities of DPhT and MPhT in aqueous and in soil extract were not significantly different. In an experiment that studied the degradation of TPhT acetate and its exposure over a period of 33 weeks, there was no degradation of TPhT in both autoclaved soils observed. The degradation pattern of TPhT was found to be a non-linear regression transformation in both spiked soils with half-life of TPhT as 26 and 20 days in non-sterile soils at 10 and 20 μg g^-1, respectively. The toxicity of TPhT mixed with its degradation products has been found to decrease after 8 weeks, this represents only a sole application.

Samples including surface sediments and seawaters were collected from eighteen ports of Pingtung County. The objective of this study were to understand sources of organotin pollution and to monitor the organotin pollution of these fishing ports by analying with gas chromatography-flame photometric detection (GC-FPD). ¡@The results showed that butyltins were the major components of organotin pollution of the fishing ports investigated. The concentrations of MBT, DBT, TBT and MPT in seawaters varied between 3.9~51.6 ng/L as tin, ND~15.2 ng/L as tin, ND~23.9 ng/L as tin and 2.1~7.2 ng/L as tin. The concentrations of MBT, DBT, TBT and MPT in surface sediments varied between 67~332 ng/g as tin, 17.6~325 ng/g as tin, 26~420 ng/g as tin and ND~43.7 ng/g as tin. ¡@The contents of organotin compounds were relevant to the number of fishing craft and the frequency of fishery activities. Distribution of organotin compounds between seawaters and surface sediments in these fishing ports were correlational. Phenyltin was detected only in a few ports, probably due to the sewage discharge from the nearby villages. The concentrations of organotin compounds observed in this study are lower than most of the reported values from foreign ports. In comparison with the previous studies in the same areas, organotin concentrations have dropped significantly. These observations are attributed to the effective control over the utilization of organotin compounds by the authorities.

No description available.

Thesis (Ph. D.)--Carleton University, 2004. / Includes bibliographical references (p. 152-160). Also available in electronic format on the Internet.

L’objectif principal de ce travail était de réaliser une étude écotoxicologique du complexe lac Ichkeul-lagune de Bizerte. Un recensement des pesticides agricoles les plus utilisés dans le bassin versant agricole a été effectué afin de déterminer les pesticides les plus problématiques. Le recensement effectué auprès des agriculteurs, des revendeurs de produits phytosanitaires et le commissariat régional de développement agricole de Bizerte a permis d’identifier les molécules les plus utilisées au niveau des zones agricoles du bassin versant du complexe lac Ichkeul – lagune de Bizerte: l’iodosulfurone, le mésosulfurone, le 2,4D, le glyphosate et le fénoxaprop comme matières actives des herbicides ; le tébuconazole et l’époxiconazole comme fongicide et la deltaméthrine matières active des insecticides. Ensuite, les concentrations en pesticides, HAP et PCB ont été déterminées. Les résultats ont montré une contamination au niveau de certains sites du complexe. Les stations situées dans la lagune de Bizerte ont des teneurs en HAP dépassant les limites tolérées. Les concentrations en pesticides dépassent les normes au niveau de quelques sites du lac Ichkeul. Enfin, l’impact de ces polluants sur les communautés microbiennes et la densité de nématodes a été déterminé. La CCA combinant les résultats des analyses chimiques et les données T-RFLP des communautés bactériennes met en évidence que les communautés bactériennes du lac sont influencées parles pesticides alors que celles de la lagune sont influencées par les HAP. La répartition des T-RFs montre la présence de T-RFs spécifiques dans les sites contaminés : le T-RF 114 bp caractérise le site le plus contaminé en pesticide, les microorganismes associés à ce T-RF correspondent probablement à des microorganismes résistants aux pesticides et capables de les dégrader. La composition des communautés bactériennes a été déterminée par pyroséquençage 454 sur les sites les plus représentatifs : le moins contaminé du complexe, le plus contaminé en HAP, le plus contaminé en pesticides et un site présentant une contamination multiple HAP-Pesticides. L’impact de la présence des pesticides sur la densité des nématodes libres marins a été étudié. L'analyse taxinomique des données de pyroséquençage regroupe les séquences dans 44 embranchements différents. En général, Proteobacteria étaient l’embranchement le plus dominant avec une prédominance de Gammaproteobacteria, Alphaproteobacteria et deltaproteobacteria dans les sédiments. Les communautés bactériennes des quatre sites ont 211 OTU commun. Le lac Ichkeul a été caractérisé par 219 OTU spécifique et la lagune de Bizerte 235 OTU. Le Site 2, le plus contaminé en pesticides présente l’abondance la plus élevée en nématodes libres marins. / The main objective of this work was to conduct an ecotoxicological study of the complex Ichkeul Lake-Bizerta lagoon. A survey of the most used agricultural pesticides in the watershed of the complex was conducted to determine the most problematic compounds. The survey of pesticides use with farmers, dealers of pesticides and the Regional Commissioner for Agricultural Development Bizerte has helped to identify the most used pesticides in agricultural areas of the watershed of the complex Ichkeul Lake-Bizerta lagoon: iodosulfuron, the mesosulfurone, 2,4D, glyphosate and fenoxaprop as herbicides active materials, tebuconazol epoxiconazol as fungicide active materials and deltamethrin as insecticides. Then, the concentrations of pesticides, PAHs and PCBs were determined in the sediment of the complex. The results showed a contamination of some complex sites. Stations located in the lagoon of Bizerte have a level of PAH in excess of permissible limits. Pesticide concentrations exceed the standards at some sites from the Ichkeul Lake. Finally, the impact of these pollutants on microbial communities and nematode density was determined. CCA combines the results of chemical analyzes and T-RFLP data of bacterial communities shows that the bacterial communities of the lake are influenced by pesticides while those of the lagoon are influenced by PAHs. The distribution of T-RFs showed the presence of specific T-RFs in contaminated sites: the T-RF 114 bp characterizes the most contaminated site in pesticides, microorganisms associated with the T-RF are probably microorganisms resistant to pesticides and capable of degrading this pollutant. The composition of bacterial communities was determined by 454 pyrosequencing of the most representative sites: the least contaminated of the complex, the most contaminated by PAH, the most contaminated by pesticides and a site with multiple PAH-pesticides contamination. The impact of the presence of pesticides on the density of free living marine nematodes was studied. The taxonomic analysis of the pyrosequencing data grouped the sequences into 44 different phyla. In general, Proteobacteria were the most dominant phyla with predominance of Gammaproteobacteria, Alphaproteobacteria and Deltaproteobacteria within the sediments. Besides Proteobacteria, there are a number of sequences affiliated to the following major phyla detected in all four sites: Chloroflexi, Bacteroidetes, Nitrospirae, Planctomycetes, Actinobacteria, Gemmatimonadetes, Firmicutes, Cyanobacteria, Spirochaetes, Acidobacteria. The bacterial communities of the four sites shared 211 common OTUs. The Lake Ichkeul was characterized by 219 specific OTUs and the Bizerta lagoon by 235 OTUs. Site 2, the most contaminated by pesticides has the highest abundance of free living marine nematodes.