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.

abstract / Biological Sciences / Doctoral / Doctor of Philosophy

Substanzen, die durch ihr hormonell wirksames Potenzial mit dem Hormonsystem interagieren und adverse Effekte auf die Reproduktion von Invertebraten und Vertebraten ausueben koennen, erlangten in den letzten Jahrzehnten große Aufmerksamkeit. Viele dieser Substanzen reduzieren die Fertilitaet oder die Fekunditaet, fuehren zu Abnormalitaeten in der Ontogenese oder im Verhalten der Tiere und haben Einfluss auf die Geschlechterverhaeltnisse. In der vorliegenden Arbeit wurden verschiedene Aspekte dieses Themengebietes bearbeitet. Das in Europa endemisch vorkommende Rotauge (Rutilus rutilus), ein Sueßwasserfisch, wurde als Modelltier fuer den Nachweis von (anti)androgenen Effekten auf aquatisch lebende Organismen etabliert. Zum Nachweis der (anti)androgenen Wirkmechanismen wurden die Tiere mit Modellsubstanzen aus drei verschiedenen Gruppen exponiert. Aus der Gruppe der Substanzen mit potenziell androgener Wirkung wurden Triphenylzinn (TPT) und Methyltestosteron (MT) verwendet, aus der Gruppe der Antiandrogene Vinclozolin (VIN) und Cyproteronazetat (CYP) und aus der Gruppe der Aromatasehemmer, und somit potenziell androgener Wirkung, Letrozol (LET) und Fenarimol (FEN). Feedbackmechanismen auf die Hypothalamus-Hypophysen-Gonaden-Achse (mRNA-Expression des Luteinisierenden Hormons, des Follikel stimulierenden Hormons und der Aromatase), mRNA-Expression potentieller Biomarker in der Leber (Androgen-Rezeptor-mRNA, Oestrogen-Rezeptor-mRNA), Sexsteroidspiegel im Blutplasma (17beta-Oestradiol und 11-keto-Testosteron), Enzymaktivitaeten im Gehirn (Aromatase), Histologie der Gonaden, Totallaenge, Gewicht und Geschlechterverteilung wurden als Endpunkte analysiert, um adverse Effekte auf die Reproduktionsbiologie von R. rutilus zu zeigen. Die untersuchten Endpunkte eigneten sich sehr gut zum Nachweis verschiedener Wirkmechanismen. / Substances that are able to interact with the endocrine system and cause adverse effects on the reproduction of invertebrates and vertebrates have gained much attention over the last few decades. Many of these substances reduce fertility or fecundity, lead to developmental abnormalities or abnormalities in the behaviour of animals and have an impact on sex ratios. The present study examines various aspects of these topics. The roach (Rutilus rutilus), a freshwater fish endemic in Europe, was established as a model animal for the detection of (anti)androgenic effects on aquatic organisms. For examination of the (anti)androgenic action, the animals were exposed to model compounds from three different groups: triphenyltin (TPT) and methyltestosterone (MT) from the group of substances with potentially androgenic effect, vinclozolin (VIN) and cyproteronacetate (CYP) from the group of antiandrogens, and letrozol (LET) and fenarimol (FEN) from the group of aromatase inhibitors, which thus have a potentially androgenic effect. Feedback mechanisms on the hypothalamus-pituitary-gonad-axis (mRNA expression of luteinising hormone, follicle stimulating hormone and aromatase), mRNA expression of potential biomarkers in the liver (androgen receptor mRNA, oestrogen receptor mRNA), steroid levels in the blood plasma (17beta-oestradiol and 11-ketotestosterone), enzyme activity in the brain (aromatase), histology of the gonads, total length, weight and sex ratios were analysed as endpoints to show adverse effects on the reproductive biology of R. rutilus. The studied endpoints are suitable for the detection of different modes of action. The histological examination of the gonads proved to be especially sensitive with the exposure to AACs to resulting in fundamental adverse damages to the gonads. It was ascertained that - in the early stages of ontogeny - androgens play as crucial of a role in the development of the gonads as previously attributed primarily to oestrogens.