Dissertations / Theses on the topic 'Endocrine disrupting chemicals in water – Toxicology'

Environmental toxicants are ubiquitous throughout the environment as a result of human activity. Among these toxicants, environmental estrogens are a category of particular concern due to their environmental prevalence and potency in altering reproductive traits. While many studies have addressed the detrimental effects of environmental estrogens on both aquatic and terrestrial organisms, few have analyzed the potential for these compounds to alter mitochondrial function. Mitochondria are the primary energy-generating system for all eukaryotic life, supporting all aspects of development, metabolism, and growth. Each cell within the body contains many mitochondria which in turn contain multiple copies of their own DNA genome, mitochondrial DNA (mtDNA). Mutations in mtDNA are responsible for a wide range of human diseases such as metabolic syndromes, cancers, and obesity. Among these mitochondrial diseases many are characterized by increased levels of heteroplasmy, multiple mitochondrial DNA haplotypes within an individual. Increased heteroplasmy can alter normal mitochondrial function and influence disease initiation and progression. To date, no studies have investigated the effects of synthetic estrogens on mitochondrial genome stability. Synthetic estrogens have the capacity to bind to estrogen receptors and initiate estrogenic responses through translocation into the mitochondrion. Despite our knowledge about the relationship of heteroplasmy and disease, we still do not have a complete grasp of the mechanisms of heteroplasmic induction. Here we report our analysis of the effects of 17α-ethynylestradiol (EE2) exposure in three studies to investigate its effect on mitochondrial genome stability. Data analysis reveals a statistically significant relationship between EE2 exposure and increased heteroplasmic frequency.

This critical overview document (COD) presents, discusses and brings together the selected portfolio of publications that the author believes make a significant contribution to the field of wastewater treatment, focusing on the removal of endocrine disrupting chemicals (EDCs) in wastewater treatment applications. The aim of the research within this COD was to investigate the fate, mechanisms and optimisation of EDCs removal in wastewater treatment applications. The key objectives were to: 1. Investigate and understand the mechanisms of removal of EDCs in wastewater and sludge treatment processes. 2. Evaluate novel methods for the removal of EDCs in water and wastewater treatment applications. 3. Establish the kinetic and thermodynamic properties of the removal processes to inform process modelling of full scale design of treatment processes.

The ubiquitous presence of anthropogenic chemicals and their transformation products in surface water represents a toxicological concern from both an ecological standpoint and a human perspective as many of these chemicals are capable of altering hormonal function. Endocrine disrupting compounds can be traced back to numerous sources and may fall under the class of pesticide, industrial chemical, pharmaceutical, personal care product, and/or heavy metals. The adrenal gland is the most common target for endocrine disruptors, although in comparison to the sex steroids, this system has received much less attention in published research. Corticosteroids play a pivotal role in many physiological processes, including immunity, cognitive function, growth, metabolism, reproduction, mineral balance, and blood pressure. A primary cell culture of rainbow trout adrenocortical cells was used to investigate the endocrine disrupting activity of two commonly detected water-borne toxicants, a personal care product, triclosan (TCS), a pesticide, dichlorophenoxyacetic acid (2,4-D), and their transformation products, methyl-triclosan (M-TCS) and dichlorophenol (DCP). Previously, it has been shown that TCS, 2,4-D, and DCP exhibit a potential for endocrine disruption, although it is currently unknown if these chemicals are capable of affecting corticosteroid balance. In this study, all four chemicals showed significant inhibitory effects on corticosteroid synthesis, even though there were considerable differences in their activity. The chemical that exhibited the highest toxicity was 2,4-D, followed by TCS, DCP, and M-TCS. Both parent-compounds proved to be more toxic than their degradation products. More research with suitable test systems is needed to determine the mechanism(s) of action of these corticosteroid disruptors and the health risk that they may present.
ix, 139 leaves : ill. ; 29 cm

Thesis (M.A.)--University of Missouri-Columbia, 2007.
The entire dissertation/thesis text is included in the research.pdf file; the official abstract appears in the short.pdf file (which also appears in the research.pdf); a non-technical general description, or public abstract, appears in the public.pdf file. Title from title screen of research.pdf file (viewed on October 29, 2007) Vita. Includes bibliographical references.

Many chemicals released into the environment are believed to disrupt normal endocrine functions in humans and animals. These endocrine disrupting chemicals (EDCs) affect reproductive health and development. A major group of EDCs that could be responsible for reproductive effects are those that mimic natural oestrogens, known as xeno-oestrogens. A number of in vivo and in vitro screening strategies are being developed to identify and classify xeno-oestrogens, in order to determine whether they pose a health risk to humans and animals. It is also important to be able to apply the assays to environmental samples for monitoring purposes. In South Africa information on the levels of EDCs in water is limited. While establishing the recombinant yeast screen bioassay (RCBA) using the yeast strain Sacchyromyces cerivisiae for oestrogenic activity, problems were experienced with contamination. Four South African laboratory water sources were assessed. From the results it was clear that the water used in the preparation of the medium for the assay was the source of oestrogenic contamination. Care should be taken to eliminate all possible sources of contamination in the test procedures to eliminate the reporting of false positive results. The fact that South African laboratory and surface waters tested positive for estrogenic activity has far reaching implications regarding reproductive and general health.

Phthalates are endocrine-disrupting chemicals (EDCs) that are known testicular toxicants, used commonly as industrial plasticizers that are found in everyday items. Di-(2-ethylhexyl) phthalate (DEHP) is the most abundant phthalate in the environment, and its primary metabolite mono-(2-ethylhexyl) phthalate (MEHP) is ten-fold more potent. The purpose of this study is to examine the cellular and molecular effects of MEHP in the development of testicular cancer. Proliferation was measured for NT2 cells exposed to 10µM and 100µM MEHP at 24 and 48 hours and for cells under controlled conditions. Methylation-specific PCR (MSP) was used to determine the methylation status of the promoter region of key testicular genes post exposure to MEHP. MEHP caused a dose-dependent negative effect on proliferation and significantly altered methylation levels for key testicular genes following exposure to 10µM MEHP and 100µM, as compared to controls. This suggests that MEHP alters proliferation and methylation of testicular tumour cells in a time- and dose-dependent manner.

The endocrine system is vulnerable to a range of chemicals in the environment. Endocrine disrupting chemicals (EDCs) are exogenous agents that can induce responses on the endocrine system because of their hormone-like activity and toxicity. Specific to this study are thyroid disrupting chemicals (TDCs), these are EDCs that specifically disrupt the thyroid hormone signalling pathway, and this may result in adverse health effects. Thyroid hormones play a crucial part in metabolism, growth, maintenance of brain function and fertility; hence disruption of the thyroid signalling axis implicates human health. We are exposed to TDCs regularly, and studies have shown an association between TDC exposure and neurobehavioural disorders, reproductive abnormalities and obesity. There is a lack of data associated to thyroid hormone receptor activity in surface and drinking water. Hence, the potential human health risks posed by thyroid disruption may therefore be underestimated. The aim of the study was to optimise and validate the GH3.TRE.Luc reporter gene bioassay that can measure thyroid hormone receptor mediated activity and cytotoxicity in drinking and source water, with relevance to water monitoring. The GH3.TRE.Luc reporter gene bioassay was established, optimized and validated to detect thyroid hormone receptor activity. The luciferace assay was used to test for metabolic activity and the resazurine cell proliferation assay was used to assess cell viability. The assay was applied to compounds with agonistic and antagonistic properties; triidothyronine (T3), thyroxine (T4), triac, tetrac, amiodarone, sodium arsenite, pentachlorophenol (PCP), ethylene thiourea, 2,2,4,4-tetrahydroxybenzophenone (THBP) and methimazole. It was also applied to environmental and drinking water samples from the Global Water Research Coalition (GWRC). Finally, the assay was applied to 48 water samples from a water treatment plant in South Africa, collected over a period of 12 months. Every month, four samples were collected. Two samples were source water samples, with one going into the treatment plant and coming out as 2 distribution pipelines (drinking water). For optimisation and validation, the dose response curves obtained for T3, T4, tetrac and triac (agonists) were comparable to literature. Antagonistic behaviour was seen in sodium arsenite, amiodarone, PCP and methimazole. Spiked water samples from the GWRC showed thyroid hormone receptor activity. Sixteen of the 48 water samples collected from the water treatment plant were positive for thyroid hormone disruptor activity. Highest activity was seen in the winter season, accounting for seasonal variations. High TDCs activity reported in the source water may be due to activities occurring near the dam. The water treatment plant seemed effective for only one of the distribution pipelines, and not the other. This study confirms that GH3.TRE.Luc Reporter Gene Bioassay is a sensitive and effective tool to identify and quantify TDC activity in pure chemicals and in complex environmental mixtures present in water. Further monitoring of water sources for TDCs is recommended to ensure water quality and safety.
Dissertation (MSc)--University of Pretoria, 2017.
School of Health Systems and Public Health (SHSPH)
MSc
Unrestricted

Endocrine disrupting chemicals (EDCs) are ubiquitous in the environment and have been detected in drinking water. Although various water treatment processes can remove EDCs, chemicals can migrate from pipes that transport water and contaminate drinking water. Globally bottled water consumption is steadily rising as an alternative to tap water, but EDCs have also been detected in bottled water. Sources of EDCs in bottled water include contamination of the water source, contamination through the production process or the migration of EDCs from the packaging material. There is limited information on EDCs in drinking water and bottled water from South Africa. The aim of this study was to determine the estrogenic activity, levels of selected EDCs and the potential health risks associated with the consumption of water from selected distribution points in Pretoria (City of Tshwane) and Cape Town as well as bottled water. The study consisted of 3 phases. Phase 1 included the analysis of drinking water samples from ten water distribution points in Pretoria and Cape Town collected over four sampling periods. In phase 2, ten brands of bottled water were analysed after exposure to different storage conditions (20°C, 40°C, light and dark) for 10 days. Samples were extracted using a C18 solid phase extraction method. Estrogenic activity was assessed using the recombinant yeast estrogen screen (YES) bioassay and the T47D-KBluc reporter gene bioassay. The extracts were analysed for di(2-ethylhexyl) adipate (DEHA), di(2-ethylhexyl) phthalate (DEHP), diisononylphthalate (DINP), dibutyl phthalate (DBP), bisphenol A (BPA), nonylphenol (NP), 17β-estradiol (E2), estrone (E1) and ethynylestradiol (EE2) using UPLC-MS. Phase 3 consisted of a scenario based health risk assessment to assess the carcinogenic and toxic human health risks associated with the consumption of distribution point and bottled water. All the samples were below the detection limit (dl) in the YES bioassay, but estrogenic activity was detected in bottled and distribution point water using the T47D-KBluc bioassay. All samples were below the 0.7 ng/L trigger value for estrogenic activity in drinking water. NP was below the dl for all the samples, E2 was detected in five distribution point samples and E1, EE2, DEHA, DEHP, DINP, DBP and BPA were detected in distribution point and bottled water samples. The estrogenic activity and levels of target chemicals were comparable to the levels found in other countries. Hazard quotients for BPA, DEHA and DINP were higher in bottled water compared to distribution point water. The greatest non-carcinogenic health risk was posed by E1 in distribution point water from Pretoria and the highest cancer risk by levels of DEHP in distribution point water from Cape Town. However, overall, health risk assessment revealed acceptable health and carcinogenic risks associated with the consumption of distribution point and bottled water. Although the potential health risks posed by the EDCs found in the water samples in this study were low, the fact that potential EDCs were found in the water samples are still of concern. A monitoring strategy that also includes water from other municipalities and other brands of bottled water are therefore recommended.
Thesis (PhD)--University of Pretoria, 2016.
School of Health Systems and Public Health (SHSPH)
PhD
Unrestricted

Thesis (DTech (Environmental Health))--Cape Peninsula University of Technology, 2012.
Environmental pollution with persistent organic chemicals and inorganic trace metals is an increasingly important issue. Recently, a variety of chemicals are introduced in a very large scale on the surface water network. The main pathway of these pollutants into the environment was identified as wastewater treatment plants (WWTPs). The extended use of chemicals in many product formulations and insufficient WWTPs has lead to an increase in the levels of the detected micro-pollutants wastewater effluents. The majority of these compounds are characterized by a rather poor biodegradability. A large spectrum of pollutants present in waste as traces has been reported to exert adverse effects on human and wildlife. Even though compounds are found in wastewater in a very small amount, they may have the undesirable capability of initiating health effect on various high forms of life. This survey constitutes the first study in the City of Cape Town to report data for a variety of priority substances (phenols and phthalate esters) in WWTP effluents and receiving rivers. These results are of critical importance since the data generated are used to generate potential health risk associated with both the organic and inorganic compounds analyzed.

Endocrine disrupting chemicals (EDCs) are ubiquitous in the environment and their presence in water bodies is documented. They discharge into surface water (SW) unmonitored, posing a threat to both aquatic and terrestrial lives. This is a challenge as not all populations have access to treated drinking water (TDW). The EDC contaminated serves as a route of exposure, together with ineffective treatment plants. Given the complexity of the endocrine system, EDCs may mimic or antagonise natural hormones or disrupt their synthesis, metabolism and excretion. The associated health effects include testicular dysgenesis syndrome, metabolic disorders and cancers. Policy and internationally standardised test methods are however sti ll limited. This study therefore aimed to assess the suitability of two assays used for screening estrogenic activity and one for androgenic activity in different water sources. The study consisted of two phases. In phase 1, water sample (tap, surface and treated wastewater) were collected from a catchment area in Pretoria. The samples and a spiked MilliQ laboratory water sample were extracted with solid phase extraction (SPE) and sent to Germany for distribution to participating laboratories. Samples (n=24) from six different countries were received to test for androgenic activity in the MDA-kb2 reporter gene assay. In phase 2, SW and TDW samples were collected from April 2015 until March 2016. The samples were filtered, extracted using SPE and assayed with the YES assay, T47D-KBluc reporter gene assay for estrogenic activity and MDA-kb2 reporter gene assay for androgenic activity. In phase 1, androgenic activity was detected in 4 out of 24 (21%) samples and ranged from 0.23 ± 0.040 ng/L to 0.008 ± 0.001 ng/L DHTEqs. In phase 2, estrogenic activity was detected in 16 out of 24 (67%) SW samples in the T47DKBluc reporter gene assay and ranged from 0.31 ± 0.05 pg/L to 10.51 ± 5.74 pg/L EEqs. It was below the detection limit (dl) in the YES assay. Androgenic activity was detected in 4 out of 24 (17%) SW samples, ranging from 0.0033 ± 0.0050 ng/L to 0.090 ± 0.040 ng/L DHTEqs. Androgenic and estrogenic activity was higher i n pretreatment samples compared to post-treatment in both treatment plants. In phase 1, the MDA-kb2 reporter gene assay was successfully applied to water samples from different sources. Androgenic activity was highest in treated wastewater. In phase 2, treatment plants proved to be effective in removing estrogens detected in the SW samples, as the TDW samples were below the dl. Estrogenic activity is within the ranges reported in other studies. Positive samples were below the 0.7 ng/L proposed trigger value for health risk assessments. Detected androgenic activity was lower in TDW samples compared to the SW samples supplying the two treatment plants indicating that they were both effective in removing the androgenic activity detected. Few studies have reported androgenic activity in tap water. This study strengthens the argument for using a battery of assays when monitoring endocrine activity as EDCs occur at low concentrations in mixtures.
Dissertation (MSc)--University of Pretoria, 2017.
School of Health Systems and Public Health (SHSPH)
MSc
Unrestricted

Orientador: Ricardo de Lima Isaac
Dissertação (mestrado) - Universidade Estadual de Campinas, Faculdade de Engenharia Civil, Arquitetura e Urbanismo
Made available in DSpace on 2018-08-18T23:00:14Z (GMT). No. of bitstreams: 1 Peres_MarianaRodrigues_M.pdf: 4938252 bytes, checksum: e65c217dee0ac585f070316b2ec3fbda (MD5) Previous issue date: 2011
Resumo: Nas últimas décadas, verifica-se um crescente interesse científico a respeito dos potenciais adversos associados à exposição humana e animal aos interferentes endócrinos. A ocorrência de interferentes endócrinos em efluente de Estação de Tratamento de Esgoto (ETE) e em águas superficiais constitui um crescente interesse científico devido à probabilidade de que esses micropoluentes não sejam removidos nos processos físico-químicos empregados em Estação de Tratamento de Água (ETA) convencional. A adsorção em carvão ativado tem sido apontada com uma opção para a remoção de interferentes endócrinos em ETA. O presente trabalho avaliou a adsorção do estrógeno natural 17?-estradiol (E2), do estrógeno sintético 17?-etinilestradiol (EE2) e do xenoestrogênio 4-nonilfenol (NP) por carvão ativado em pó (CAP) em água deionizada e água bruta do rio Atibaia. Os procedimentos analíticos empregados foram extração em fase sólida e análise por cromatografia gasosa acoplada a detector de massas (CG-EM). O modelo de Freundlich foi o que melhor representou a adsorção dos compostos nos carvões ativados usualmente aplicados nas estações de tratamento de água de Campinas-SP. Em água deionizada, a remoção mais significante dos compostos foi observada na dosagem de CAP equivalente a 15 mg/L, alcançando níveis de remoção da ordem de 95%. Os resultados obtidos nos ensaios com água bruta demonstraram que a dosagem de 10 mg/L apresenta eficiência superior a 77% na remoção dos interferentes endócrinos da água do manancial. Observou-se que o CAP com número de iodo superior a 800 mg/g apresentou, de modo geral, as melhores eficiências de remoção, favorecendo a adsorção dos compostos nos microporos do carvão. Considera-se que, embora ainda não exista legislação em vigor no Brasil que limite a presença desses micropoluentes na água de abastecimento público, recomenda-se que a adição de CAP seja realizada pelo princípio da precaução
Abstract: In the last decades, a growing scientific concern has been raised over the potential adverse effects associates to human and animal exposure to endocrine disrupting chemicals (EDC). The occurrence of these compounds in wastewater treatment plant (WWTP) effluent and surface waters has been an interesting research field due to the probability of these micropollutants to break through water treatment plant (WTP). Adsorption on activated carbon has been recognized as an option for the removal of EDC. Present paper evaluated the adsorption of the natural estrogen 17?-estradiol (E2), the synthetic estrogen 17?-ethinylestradiol (EE2) and the xenostrogen 4-nonylphenol (NP) by powdered activated carbon (PAC) in ultra-pure water and raw water from Atibaia River, at Campinas City, São Paulo State, Brazil. The analytic technique used was solid phase extraction (SPE) and gas chromatography tandem mass spectrometry (GC-MS). Freundlich's model resulted more adequate to describe the adsorption of the compounds on PAC usually applied at local WTP. In ultra-pure water it was observed more significant removal for dosages equal to 15 mg PAC/L, reaching 95% of removal. The results obtained for raw water showed that 10 mg/L PAC dosage promotes a removal of the endocrine disruptor from river water higher than 77%. It was observed that PAC with iodine number greater than 800 mg/g presented, in general, the highest removal efficiencies, supporting the adsorption of compounds in the activated carbon micropores. Although there is no current legislation in Brazil that regulates the presence of these micropollutants at water supply systems, the addition of PAC must be performed by the precautionary principle
Mestrado
Saneamento e Ambiente
Mestre em Engenharia Civil

Sewage effluents disposed into the marine environment from De Beers Marine Namibia diamond mining vessels have the potential to cause endocrine disruptive effects in marine organisms. Endocrine disruption refers to the alteration of the normal functioning of the endocrine system and various chemicals have the ability to mimic hormones, effecting endogenous hormone synthesis, transport, receptor interaction and intracellular signaling. The potential endocrine disruptive effects, caused by the release of different types of sewage effluents into the ocean, on fish species is a concern due to the commercial importance of fish species found in the mining area e.g. hake, sole, horse mackerel. Increased awareness of marine environmental degradation due to the presence of chemical contaminants has resulted in research being done on early warning systems, in the form of biomarkers. Cytochrome P450 monooxygenase 1A (CYP1A) and vitellogenin (vtg) are important proteins found in fish liver and blood, that have been used as biomarkers for the detection of pollutants in fish. CYP1A is a subfamily of the P450 superfamily of enzymes and catalyzes the oxidation, hydrolysis and reduction of exogenous and endogenous compounds (phase I reactions) and thus has the capacity to regulate the metabolism of several organic contaminants. CYP1A expression is altered by exposure to planar xenobiotic compounds e.g. polyaromatic hydrocarbons. Vtg is an important precursor for egg yolk proteins and plays a role in the growth and development of an oocyte. Expression of this protein is altered upon exposure to estrogenic compounds. The aim of this project was to isolate CYP1A from fish liver by differential centrifugation and optimize conditions for the CYP1A-mediated ethoxyresorufin-Odeethylase (EROD) assay and western blot analysis (to assess CYP1A expression). Another aim of this study was to evaluate the potential effects of biologically disruptive chemicals from sewage effluents, discharged into the marine environment, on the expression of CYP1A in two species of hake, Merluccius capensis and M. paradoxus (Cape hake). CYP1A in Cape hake is approximately a 60 kDa protein and the highest EROD activity was detected in the microsomal fraction after differential centrifugation. Optimal EROD assay conditions were observed at pH 7.5, a temperature of 25 °C, 10 μl of sample and a reaction time of 30 seconds. Enzyme stability assays indicated a drastic decrease in enzyme activity after 30 seconds. The EROD assay was not NADPH dependent but was limited by NADPH supply, with an increase of 300% in EROD activity being observed with the addition of 0.1 M exogenous NADPH. The addition of dicumarol (40 μM), a phase II enzyme inhibitor, showed a 232% increase in EROD activity. This is because dicumarol inhibited enzymes with the capacity to metabolize the product (resorufin) of the EROD reaction. With regard to western blot analysis, the optimal primary (rabbit antifish CYP1A peptide) and secondary (anti-mouse/rabbit antibody-horseradish peroxidase conjugate (POD)) antibody dilutions were determined to be 1:1000 and 1:5000, respectively. The comparison of CYP1A expression in Cape hake samples from De Beers Marine mining area and reference sites showed higher EROD activity (16.29 ± 0.91 pmol/min) in fish samples from the mining area in comparison to the reference site (10.42 ± 2.65 pmol/min). Western blot analysis was in agreement with the EROD assay results and a higher CYP1A expression was observed in fish from the mining sites. The increased CYP1A expression observed in fish from the mining area is not definitively an indication of a pollutant effect in the environment, as several environmental and biological factors (e.g. photoperiod and age) must also be considered before reaching this conclusion. Another aim of this study was to purify vtg from Cape hake blood samples. Cape hake vtg was purified from fish plasma by selective precipitation with MgCl2 and EDTA. Precipitated sample was subjected to anion exchange chromatography using fast protein liquid chromatography (FPLC). Vtg eluted as two broad peaks and had a molecular weight above 200 kDa. SDS-PAGE analysis also resolved smaller molecular weight proteins below 70 kDa, which were thought to be vitellogenin cleavage proteins, lipovitellin and phosphovitins. Western blot analysis was performed; however, it did not produce any conclusive results. The purification of vtg enables further studies in characterizing this protein and developing assay aimed at detecting estrogenic pollutants in the marine environment

Interferentes endócrinos (IE) são substâncias capazes de afetar o sistema endócrino causando danos à saúde. Os compostos estrogênicos são um tipo de IE que geram resposta biológica semelhante aos hormônios endógenos, chamada atividade estrogênica, são frequentemente encontrados no ambiente devido à poluição de origem antrópica e ineficiência de processos de tratamento de água e esgoto. O objetivo deste trabalho foi avaliar a atividade estrogênica de águas de mananciais e águas tratadas para abastecimento no Estado de São Paulo por meio de bioensaios. Foram utilizados dois métodos, baseados em diferentes linhagens da levedura Saccharomyces cerevisiae capazes de responder a agentes estrogênicos pela presença do gene que codifica para o receptor de estrogênio humano e sistemas de gene repórter da atividade estrogênica. Uma das linhagens contém o gene luc, método denominado neste trabalho de Lesk, enquanto a outra contém genes lux como repórter, denominado método San. Os métodos foram comparados quanto à especificidade e sensibilidade de resposta aos principais interferentes endócrinos de ocorrência em águas e com dados de análises cromatográficas das respectivas amostras ambientais. Foi observada atividade estrogênica expressiva nas águas brutas coletadas em pontos específicos nas cidades de Campinas, Barueri, Cerquilho e em efluente hospitalar e em todas essas amostras foram detectados compostos estrogênicos-alvo. As amostras de água tratada não apresentaram atividade estrogênica nem compostos estrogênicos, com apenas uma exceção. O método San foi mais sensível que o método Lesk, tanto para compostos químicos puros quanto para amostras ambientais. O teor de substâncias detectado por análises cromatográficas não foi suficiente para explicar a atividade estrogênica observada nos bioensaios, indicando que concentrações abaixo dos limites de detecção podem gerar o efeito biológico ou que compostos estrogênicos não estudados e suas misturas podem estar presentes gerando efeitos aumentados.
Endocrine disrupting (ED) chemicals are compounds able to interact with the endocrine system causing health adverse effects. Estrogenic compounds are a type of ED that produce a biological response similar to organism\'s natural hormones, called estrogenic activity; they are frequently found in the environment and are usually associated to the pollution from human activities. The goal of this work was to evaluate the estrogenic activity of rivers raw and treated water around the State of São Paulo Brazil - using bioassays. Two different strains of Saccharomyces cerevisiae able to respond to estrogenic compounds, due to the presence of genes that encodes for the human estrogen receptor, were used. One of the strains has the luc gene (method Lesk), a reporter of estrogenic activity and the other contains lux genes (method San) as reporter of estrogenic activity. Both methods were compared regarding their specificity and sensitivity for chemical substances and environmental samples. The results were also compared with the chemical analysis data of target pure compounds in those waters and with the literature. Estrogenic activity was detected in raw water samples collected in Campinas, Barueri and Cerquilho and also in hospital effluent, for all those samples estrogenic compounds were determined. San method showed to be more sensitive to pure chemical compounds and environmental samples. For treated water no estrogenic activity was found, except for one sample from Barueri that presented a low response. The amounts of compounds detected by chromatographic analysis were not sufficient to explain the observed estrogenic activity when bioassays were used, therefore low compounds concentration or other compounds and their mixtures may be responsible for the high biological effet detected by bioassays.

Endocrine disrupting compounds and pesticides have been detected in rivers and irrigation canals of Southern Alberta, a semiarid region with irrigation-dependent crop production, intensive livestock operations, and a growing human population. However, little is known about the effects of agricultural runoff or wastewater treatment plant (WWTP) effluent in Southern Alberta on fish. Reproductive effects of WWTP effluents from the cities of Lethbridge and Medicine Hat, as well as agricultural runoff in the Lethbridge Northern Irrigation District canals, were investigated in a field study with wild fathead minnows (FHMN) in the Oldman and the South Saskatchewan rivers, in Alberta, Canada, and in a laboratory study with laboratory reared FHMN exposed in vivo to the city of Lethbridge WWTP effluent for 21 days. Biochemical and morphological endpoints were measured to characterize reproductive status. Liver vitellogenin, a biomarker of exposure to estrogen mimics, was analyzed using quantitative RT-PCR, and gonadal histology was used to determine sex, gonadal maturity, and intersex. Adverse reproductive effects were detected in FHMN exposed for 21 days to 10 and 25% of Lethbridge WWTP effluent. In the field, effluents from both Lethbridge and Medicine Hat had an effect on the reproductive systems of FHMN. In canals, reproductive effects were detected in wild fathead minnows in years when water quality in irrigation drain canals decreased. Exposure to pesticides was estimated using acetylcholinesterase (AChE) inhibition. Exposure to Lethbridge WWTP effluent did not inhibit AChE, whereas results from the field study were inconclusive. In conclusion, reproductive systems of fathead minnows in Southern Alberta were impacted by anthropogenic chemicals.
xi, 104 leaves : ill. (some col.), maps ; 29 cm

Los compuestos disruptores endocrinos (EDCs) son sustancias exógenas capaces de alterar las funciones del sistema endocrino y la regulación del desarrollo embrionario, y por consecuencia, con capacidad de provocar efectos adversos sobre la salud de un organismo o su progenie (WHO, 2012). Hay un aumento de preocupación no solo por la presencia de estos compuestos en el medio ambiente, sino por los efectos biológicos que pueden ejercer sobre la salud humana y de animales. Los EDCs pueden ser compuestos naturales y sintéticos Tienen diversos mecanismos de actuación y presentan características propias, de forma que cada EDC tiene una curva Dosis-Respuesta No Monotónica (NMDR) característica, pueden ejercer mayores efectos estrogénicos a dosis muy bajas (low dose), el momento de la exposición a los EDCs es crítico, siendo mayor e irreversible en la fase prenatal, tienen largos periodos de latencia. En los últimos 10 años ha habido muchos avances en su conocimiento y se han relacionado enfermedades tan comunes como la diabetes y la obesidad y hay estudios sobre sus efectos, que pueden manifestarse a lo largo de varias generaciones a través de la epigenética. Son compuestos que entran en el medio acuático principalmente por las descargas de las estaciones depuradoras de aguas residuales y pueden distribuirse en distintos compartimentos, siendo adsorbidos en fangos, sedimentos y material particulado. Las mezclas de EDCs a las que estamos expuestos en el medioambiente pueden presentar efectos sinérgicos, antagónicos, inhibitorios o aditivos. Presentan actividad estrogénica a concentraciones muy bajas (los estrógenos a 1-10 ng/L y los alquilfenoles a g/L). La gran variedad de propiedades físico-químicas de los EDCs y las bajas concentraciones a las que están presentes en el medioambiente, hace que su determinación represente un reto por su complejidad, por lo que se necesita métodos químicos muliresiduo sensibles, así como técnicas biológicas que permitan determinar la actividad estrogénica que presentan a concentraciones muy bajas. Por tanto, ante la actual problemática de la contaminación del agua por compuestos disruptores endocrinos, y la creciente preocupación por los efectos biológicos que pueden tener sobre la salud y el medioambiente, esta tesis responde a la demanda de métodos analíticos para su determinación y control, y a la necesidad de establecer metodologías integradas con técnicas biológicas para la determinación no solo de las bajas concentraciones a las que los EDCs están presentes en el medioambiente acuático, sino también de su actividad estrogénica. Con este objetivo, en esta tesis se ha llevado a cabo la optimización de una metodologías integrada, de cromatografía líquida acoplada a espectrometría de masas para identificar los EDCs en el medio acuático, con análisis confirmatorio de estrógenos mediante LC-MS(MS) y el bioensayo con levaduras recombinantes (RYA) que determina de forma cuantitativa la estrogenicidad total de la muestra, detectando tanto los estrógenos naturales como los xenoestrógenos sin tener en cuenta la identidad de los compuestos químicos responsables de este efecto. Adicionalmente, Se han validado inmunoensayos ELISA para la determinación de compuestos alquilfenólicos en aguas, que permiten realizar un previo screening y analizar un gran número de muestras en menor tiempo y a coste inferior en Programas de Vigilancia Ambiental (PVA) Se han llevado a cabo PVAs en Portugal y en las cuencas de los ríos Llobregat y Ter en Cataluña (Nordeste de España). La actividad estrogénica ha sido atribuida principalmente a los compuesto alquilfenólicos, más ubicuos, mientras que en los puntos en los que se han identificado y confirmado estrógenos mediante LC- MS/MS, éstos compuestos tienen mayor contribución a la estrogenicidad total. Los resultados obtenidos ponen de manifiesto la importancia de analizar la fracción particulada en aguas para determinar la concentración total de compuestos alquilfenólicos, debido a la distribución de los compuestos más estrogénicos (nonilfenol y octilfenol) en el material particulado y la absorción en los fangos. El bioensayo RYA ha detectado una baja actividad estrogénica en las aguas superficiales, mientras que el análisis del PM en aguas residuales ha permitido obtener una mayor eliminación de la estrogenicidad (95- 97%), más importante medioambientalmente las concentraciones químicas por los potenciales efectos que puede producir en la fauna y los seres humanos. Finalmente, el desarrollo de técnicas más avanzadas para la determinación de EDCs, el aumento de publicaciones científicas, y el hecho de que los principales EDCs estudiados en esta tesis (NP, BPA, DEHP, E1, E2, E3) han sido posteriormente incluidos en la normativa europea y de USA de contaminantes prioritarios (D. 2008/105/EC, D. (UE) 2015/495/EC, Reglamento REACH y D. (UE) 2003/53/EC), ponen de manifiesto la relevancia de los compuestos estudiados.
There is growing evidence that some compounds, known as endocrine-disrupting compounds (EDCs), can mimic or antagonize the actions of steroid hormones, affecting the health of humans and wildlife species by disrupting their normal endocrine function. EDCs are natural and synthetic compounds that can be found in the aquatic environment as a result of the chemical industry, pharmacy and household applications. We are exposed to mixtures of EDCs that can exert physiological effects, synergic, antagonist o additive, at very low concentrations (i.e. -estradiol and ethinylestradiol are reported to be estrogenic to fish at levels as low as 0.1 to 10 ng/L). Over the past decade there have been significant advances in our understanding of EDCs, their mechanisms of action and biological effects on human and wildlife health, suggesting a greater role for EDCs in disease than what was predicted. EDCs have Non-Monotonic Dose Response corves, they can exert effects at lower doses than expected, the moment of the exposure is critical, their effects can have latency periods and even pass to other generations. To control the endocrine disruptors, there is a need for monitoring large numbers of samples and for methodologies, not only to identify the EDCs at the low dose that they are present in the environment, but also to assess their estrogenic activity. This thesis responds to increasing concerns on this matter, providing an integrated methodology that combine analytical methods by LC-MS(MS) to determine the presence of EDCs at low concentrations in the environment, as well as biological techniques (Recombinant Yeast Assay, RYA) to assess their estrogenic activity in environmental samples. In addition, ELISA immunoassays have been validated as a screening tool for a rapid and cost-effective detection of alkylphenolic compounds in water samples in monitoring programs. Monitoring programs were performed in Portugal and the Llobregat and Ter River basins in Catalonia, Spain. Estrogenic activity was mainly attributed to alkylphenolic compounds, whereas in a few samples, the estrogens identified and confirmed by LC-MS/MS were responsible for the estrogenicity. The obtained results pointed out the importance to analyze the particulated fraction of waters to determine the total concentration of alkylphenolic compounds, due to partitioning of the most estrogenic (nonylphenol and octylphenol) upon particulate matter (PM) and enrichment in sludge. RYA showed weak estrogenic activity in surface water samples, whereas the analysis of PM in wastewaters permitted to obtain higher removal of estrogenicity (95-97%) than chemical concentrations, more important from the environmental point of view. Finally, due to their estrogenic properties, some of the EDCs studied in this thesis (i.e. Nonylphenol, DEHP, estradiol, ethinylestradiol) have been included in the European regulation (D. 2000/60/EC, D. 2008/105/EC, D. 2015/495/EC, REACH Regulation and D. 2003/53/EC) and in the US EPA priority list, confirming the relevance of the target compounds selected.

The disposal of waste from agricultural activities has been recognised as a source of environmental contamination by endocrine disrupting chemicals (EDCs). The New Zealand dairy industry produces a large volume of dairy farm effluent, which contains EDCs in the form of estrogens. Most of this dairy farm effluent is applied onto the land for disposal. Groundwater and soil contamination by estrogens following waste application on the land have been reported overseas, but our understanding of the processes and factors governing the fate of estrogens in the soil is poor. Therefore the main goal of the present study was to better understand the fate and transport of estrogens, in particular 17β-estradiol (E2) and estrone (E1) in soil. In order to quantify E1 and E2 in drainage water and soil samples, chemical analysis by gas-chromatography mass-spectrometry (GC-MS) was carried out. This included sample extraction, sample clean-up through silica gel and gel permeation chromatography, and sample extract derivatisation prior to analysis. In order to develop a reliable method to extract estrogens from soil, research was conducted to optimise E1 and E2 extraction conditions by adjusting the number of sonication and shaking events, as well as the volume and type of solvent. Among five solvents and solvent mixtures tested, the best recovery on spiked and aged soil was obtained using an isopropanol/water (1:1) mix. A microcosm experiment was carried out to determine the dissipation rates of E2 and E1, at 8°C and at field capacity, in the Templeton soil sampled at two different depths (5-10 cm and 30-35 cm). The dissipation rates decreased with time and half-life values of 0.6-0.8 d for E1 and 0.3-0.4 d for E2 were found for the two depths studied. A field transport experiment was also carried out in winter, over three months, by applying dairy farm effluent spiked with estrogens onto undisturbed Templeton soil lysimeters (50 cm in diameter and 70 cm deep). The hormones were applied in dairy farm effluent at 120 mg m⁻² for E2 and 137 mg m⁻² for E1. The results of the transport experiment showed that in the presence of preferential/macropore flow pathways 0.3-0.7% of E2 and 8-13% of E1 was recovered in the leachate at the bottom of the lysimeters after 3 months, and 1-7% of the recovered E2 and 3-54% of the recovered E1 was leached within 2 days of application. These results suggest that leaching of estrogens via preferential/macropore flow pathways is the greatest concern for groundwater contamination. In the absence of preferential/macropore flow pathways, a significant amount (> 99.94%) of both hormones dissipated in the top 70 cm of soil, due to sorption and rapid biodegradation. Surprisingly, in all cases, estrogen breakthrough occurred before that of an inert tracer (bromide). This could not be explained by the advection-dispersion transport of estrogens, nor by their presence as antecedent concentrations in the soil. It was therefore suggested that colloidal enhanced transport of estrogens was responsible for the earlier breakthrough of estrogens and caused the leaching of a fraction of the applied estrogens to a soil depth of 70 cm. A two-phase model, adapted from a state-space mixing cell model, was built to describe the observed estrogen transport processes under transient flow. The model takes into account 3 transport processes namely, advection-dispersion, preferential/macropore flow and colloidal enhanced transport. This model was able to successfully describe the estrogen transport observed from the lysimeters.

Submitted in fulfillment of the requirements for the degree of Doctorate of Technology: Biotechnology, Durban University of Technology, Durban, South Africa, 2014.
All over the world concerns have been raised over the possible adverse effects that may occur when exposed to chemicals that have the potential to interfere and affect the endocrine system. The concern is directed at both humans and wildlife. There is still a lack of public awareness regarding Endocrine Disrupting Chemicals (EDCs) and the harmful effects on humans and wildlife. It has only been within the last decade that South Africa began the actual task for proper management and control for water and wastewater quality. There are many ways to detect these EDCs all of which are very laborious and most of the cases these EDCs are either in the pico or nano gram per litre range, too minute for many methods to detect effectively; so therefore the research project aimed to use rapid and sensitive techniques to determine the quickest means to detect the very low concentrations of theses EDCs. Two techniques were researched, i.e., Enzyme Linked immunoassays (ELISAs) and Radio-immunoassays (RIAs). The research study thus assessed the solid phase extraction (SPE) technique for total recovery of hormones; the ELISA and RIA techniques for rapid detection of natural (estrone (E1), estradiol (E2) and estriol (E3) and synthetic ethinylestradiol (EE2) by validating the precision and reproducibility . These techniques were then applied to determine hormone EDC removal first at laboratory scale investigations and then applied to full scale wastewater treatment plants (WWTP) with different configurations in order to deduce removal efficiency of each type of plant. The next phase assessed the toxicity of individual and combined estrogen standards as well as the toxicity in the WWTPs and classify and to determine if there was a correlation between hormone concentration and toxicity in final effluents. The assessment of the SPE and the immunoassay procedures (ELISA AND RIA) using standards and controls found that both these assays can be utilised to quantify hormone estrogens in wastewater. The small sample volume required reduced the labour time and application of the procedure made it cost effective and reliable techniques. The intra-assay and inter-assay validation procedures as well as the standard recoveries confirmed reproducibility and precision of the immunoassays. The % CV were <10% for both the intra-assay and inter-assay validations. The laboratory scale investigations included the operation of a modified Ludzak-Ettinger (MLE) process which enabled control and manipulation over the operational parameters in order to establish how certain parameters influenced the removal of hormone EDCs. One such parameter that was manipulated was the sludge retention time (SRT). The MLE tests showed that the SRTs definitely have an effect on the removal of hormones from the influent as well as the overall performance of sewage treatment. The 10 day SRT proved that longer SRTs will definitely aid in the removal of hormones and possibly other EDCs in raw sewage. During the 10 day SRT the influent hormone concentrations (E1: 59.11 ng/L, E2: 61.40 ng/L) were almost double than the influent hormone concentrations (E1: 26.46 ng/L, E2: 27.60 ng/L) during the 5 day SRT, which impacted on the removal efficiency. The 5 day SRT had an overall average E2 and E1 removal of 78.11% and 81.71% respectively while the 10 day SRT had average E2 and E1 removal of 91.24 % and 80.56% respectively. The 24 hour batch test provided evidence of the reversible metabolism of the E2 hormone. This was seen by the rapid decrease of E2 and the rapid increase of E1 in less than 3 hours, which proved that E2 can be metabolized in to E1. An average reduction of 94.44% of E2 was seen after 5 hours and after 10 hours was no longer detected. After 13 hours E1 could no longer be detected. This finding also provided clarity as to the lower percentage removal of E1 during the 10 day SRT of the MLE process. The Vibrio fischeri biotox method implemented was the most economic and easiest way to conduct the toxicity tests. The validation of the test used a 52.9 mg/L K2Cr2O7 standard which provided a Cr (VI) concentration of 18.7 mg/L in the final test suspension which is the theoretical effective concentration causing 50% inhibition (EC50). This specific concentration of the Cr (VI) exhibited an EC50 at 20.08 mg/L. The toxicity investigations of the individual and mixed hormone standards revealed that at the 10 ng/L concentration the individual E2 standard had the highest percentage inhibition (%INH) of 45.99% after the 30 minute contact time (T30), and when this standard was further diluted to 5 and 1 ng/L also showed higher % INH (26.04 and 23.66 %INH, respectively) than the individual EE2 standard (21.92 %INH) at 10 ng/L. . According to the toxicity classification system and after interpretation of the data, all the hormone standards were classified as Class II as they all exhibited slight acute toxicity. The 10 ng/L E2 standard had Toxicity Units (TU) of 0.8 which was close to the Class III level; however when it was in a mixture with E1 and E3, the TU was much lower (0.6 TU). The synthetic EE2 hormone also showed slight acute toxicity and had the lowest TU of 0.4. The application of the above mentioned techniques to full scale WWTPs with different configurations showed different removal efficiencies. The WWTPs ranged from the most primary consisting of just oxidation ponds to biological trickling filters, to biological nutrient removal (BNR) to conventional activated sludge (AS) plants. Removal rates ranged from 29% to 96% for E2, 0% to 89% for E1 and 0% to 100% for EE2. The overall ranking of the WWTPs from the most efficient to least efficient in terms of hormone removal were as follows: Plant E (91%) = Plant D (before UF) (91%) > Plant B (east side) (88%) > Plant B (west side) (77%) > Plant C (east side) (71%) > Plant D (after UF) (57%) > Plant A (56%) > Plant C (west side) (12%). Using the Vibrio fischeri method to evaluate the reduction of toxicity in WWTPs C, D and E proved effective. It was seen immediately after secondary biological treatment in the clarifier effluent the toxicity was reduced. Plants C, D and E had reduced the toxicities by 100, 80 and 97 % immediately after secondary biological treatment, while after the addition of the Chlorine disinfectant in the final stage of treatment the toxicity increased having %INH of 99.9, 15.7 and 99.9 respectively. In conclusion the SPE can be used as an extraction procedure for hormones in wastewater and the immunoassays can be used as rapid techniques for quantification of hormone EDCs in wastewater. The ELISA technique proved to be the slightly superior to the RIA in terms of facilities required. The laboratory scale procedures proved that some hormones can be oxidised to other hormones and therefore longer sludge retention times may be required to improve the removal. The study of the different WWTPs configuration showed that plant configuration and operational parameters impact the removal of hormone EDCs. The composition of the influent received by the plant also has an effect on the removal, i.e., whether it’s industrial, domestic or a mixture of both. Results concluded that plants which have either mixing and/or aeration with activated sludge and longer SRTs of more than 10 days have a higher rate of hormone removal than those plants with shorter SRTs and that the activated sludge processes were capable of reducing the toxicity of the influent. Overall results indicated that hormone EDCs are indeed being discharged with the effluents from WWTPs in South Africa. However whether the concentrations left in the final effluents will still have an adverse effect on the aquatic life is a question that still remains unanswered. The aquatic ecosystems are inevitably being polluted with these EDCs and their breakdown products.
D

Steroid hormones belong to a group of compounds known as endocrine disruptors. They are hydrophobic compounds and are categorized as natural and synthetic estrogens. Some common household products have been implicated as estrogen mimics. Exposure effects of these compounds are felt by human and wildlife, such reproductive alterations in fish and frogs. They mainly introduced into the environment through veterinary medicines administration to animals and the discharges from wastewater treatment plants (WWTPs). In this study, a new alternative analytical procedure that is simple, rapid and fast for the determination and quantification of five steroidal hormones: estriol (E3), beta estradiol (β-E2), alpha estradiol (α-E2), testosterone (T), progesterone (P) and bisphenol A (BPA) using the High pressure liquid chromatography coupled to a charged aerosol detector (HPLC-CAD). These compounds were studied because of their strong endocrine-disrupting effects in the environment. Under optimum conditions, a linear graph was obtained with correlation coefficient (R2) ranging from 0.9952 - 0.9996. The proposed method was applied to the analysis of water samples from a wastewater plant and the results obtained were satisfactory. The limits of detection (LOD) for the target analytes in wastewater influent was between 0.0002 – 0.0004 μg/L and the limit of quantification (LOQ) was 0.001 μg/L respectively for each of the analytes. Enrichment factors of 148- 258, and extraction efficiency 84- 102% were obtained for the target analytes; relative standard deviations (% RSD) for m = 6 were between 2.8 and 7.6%. The concentration of the EDCs in environment sample was between 0.2 - 2.3 μg/L.
Chemistry
M. Sc. (Chemistry)

碩士
逢甲大學
環境工程與科學所
100
In recent years, many countries have gradually started to notice the important issue of endocrine disrupting chemicals (EDCs). In 1997, Japan first proposed 70 suspected EDCs and held the international conference of endocrine disrupting substances in 1998. The United States presented another endocrine disrupting chemicals screening program in 1998 and pointed out 87,000 chemicals to the research program of endocrine disrupting chemicals. Until recently, many countries including Taiwan have showed that great interesting of EDCs in the environment. in past decade, the endocrine disrupting chemicals have caused many social problems, therefore, the Taiwanese Environmental Protection Agency began to promote an environmental hormones management plan, in order to protect the people''s living. In this study we have developed a green method by using the ionic liquid [Bmpy][Tf2N] pre-concentration environmental water samples of bisphenol A and 2,4-dichlorophenol by micro-extraction and analyze by high performance liquid chromatography (HPLC) coupled with UV detector. And compare with the use of traditional organic solvent such as hexane to show the extraction effectiveness for bisphenol A and 2,4-dichlorophenol from water samples. The experimental optimal conditions: the detection wavelength at 200 nm, the mobile phase of methanol and deionized water was 60/40 (v/v). The method detection limit (MDL) of bisphenol A and 2,4-dichlorophenol were 0.18 mg/L and 0.18 mg/L respectively. The concentration of environmental sample lower than the MDL could be detected by this micro-extraction method. The recoveries for both bisphenol A and 2,4-dichlorophenol were more than 95% and 96%, respectively. Our experimental results have demonstrated that the micro-extraction by [Bmpy][Tf2N] and combined with HPLC-UV could detect the trace limit of environmental hormones such as bisphenol A and 2,4-dichlorophenol in the natural water samples.

D.Phil.
The endocrine system regulates important physiological processes in an organism. Numerous natural and synthetic chemicals are released into the environment and can disrupt the normal functioning of the endocrine system, influencing physiological processes even at relatively low concentrations. These chemicals are known as endocrine disrupting chemicals (EDCs). These compounds are highly persistent in nature due to a resistance to biodegradation, and because of their hydrophobicity. EDCs bio-accumulate especially in the fatty tissue of aquatic and terrestrial organisms. Developmental and reproductive disorders are potentially harmful effects of exposure. EDC sources include agricultural and urban runoff, and industrial effluent discharges that eventually pass through sewage- and wastewater treatment plants. These chemicals degrade at various rates and to varying extents during treatment processes, forming many new chemicals. Methods to predict the occurrence of endocrine disruption include the occurrence of intersex, and changes in spermatogenesis and secondary sexual characteristics (SSCs) of supposedly exposed organisms. The urogenital papilla (UGP) is a SSC whose development and morphology is hormonally controlled and may be influenced when exposed to EDCs. The sharptooth catfish (Ciarias gariepinus) is often used in environmental toxicity studies. Sex is determined by the external dimorphic UGP found only in males. Intersex has been observed in this species in South African freshwater systems. A field study was carried out in the Rietvlei (RVD) and Marais (MD) dams in the Rietvlei Nature Reserve (RNR). MD acts as a sedimentation dam before water enters RVD, and is theoretically more polluted. The RNR system receives effluent from various domestic and industrial sources including agriculture, industries, informal settlements and municipal sewage treatment plants. Four sampling surveys, two low and two high flow, were carried out over a period of two years. Supposedly male catfish (n=97) were collected and identified as male or possible intersex based on the UGP. Water and sediment was collected for target EDC and endocrine disrupting metal (EDM) analyses. Fish length and mass, and UGP length and width were measured. Laparotomy was performed and gonads were inspected macroscopically for alterations. A section of the gonad and the entire UGP was removed and processed according to standard techniques for histological analysis. The gonadosomatic- (GSI), hepatosomatic- (HSI) and UGP length (UGPLI) indices were calculated. Fish fat was removed and analysed for target EDCs.

MSc (Zoology)
Department of Zoology
Many chemicals released into the environment are believed to disrupt normal endocrine functions in humans and animals. These endocrine disrupting chemicals (EDCs) affect reproductive health and development. A major group of EDCs that could be responsible for reproductive effects are those that mimic natural oestrogens, known as xeno-oestrogens. A number of in vivo and in vitro screening strategies are being developed to identify and classify xeno-oestrogens, in order to determine whether they pose a health risk to humans and animals. It is also important to be able to apply the assays to environmental samples for monitoring purposes. Oestrogens and androgens mediate their activity via intracellular receptors – directly in muscular tissue as well as indirectly via stimulation of growth hormones from the pituitary glands and other growth factors from liver plus several other organs. Mancozeb is a metal ethylenebisdithiocarbamate (EBDC) fungicide used to protect many fruits and vegetables and field crops against pathogenic fungal. It causes a variety of defects on the female reproductive system in experimental animals and is therefore considered a suspected EDC. This fungicide can also induce toxic effects in cells of the immune system and other non-immune cells leading to genotoxicity and apoptosis. The mechanisms of EDCs involve divergent pathways including (but not limited to) oestrogenic, antiandrogenic, thyroid receptors; that are highly conserved in wildlife and humans, and which can be modelled in laboratory in vitro and in vivo models. The endocrine disrupting properties of Mancozeb are not known as of yet and therefore the T47D-KBluc reporter gene assay, GH3.TRE-Luc and MDA-kb2 reporter gene assay were used determine the possible endocrine disrupting activity/potential there-of. No activity was detected in any of the assays and no mancozeb was detected in any of the dams either. Oestrogenic activity was detected in Albasini Dam, Nandoni Dam and Xikundu weir but all values were below 0.7 ng/ℓ trigger value for oestrogenic activity in drinking water.
NRF