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Thiophene Analogs of DDT; O-Alkylhydorxylamine Hydrochorides; Dialkylaminoalkyl Esters of Phenoxyacetic AcidMattison, Marjorie Bess 08 1900 (has links)
This thesis describes three separate and unrelated chemical experiments. The first investigates analogs for the compound DDT. The second investigates the properties of O-substituted hydroxylamines. The third investigates the action of slight changes to the structure of an antihistaminic agent.
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Spartial distribution and environmental compartmentalization of DDT and its metabolites in different environmental media (soil, water and plants) in Tshilamusi Area, Mutale district in Limpopo Province, South AfricaMakoni, Tonderai 10 February 2016 (has links)
MEnvSC / Department of Ecology and Environmental Science
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To spray or not to spray with DDT to control malaria : a case study in environmental ethicsMorodi, Thabiso John 03 1900 (has links)
Thesis (MPhil)--Stellenbosch University, 2003. / Full text to be digitised and attached to bibliographic record. / ENGLISH ABSTRACT: This assignment is devoted to an in depth analysis of the pro- and the contra-positions
in the long-standing and costly debate about the question whether to spray with DDT
or not in the fight against malaria. I argue that the dilemma whether or not to spray
with DDT is born out of a political agenda, hype, exaggeration and misinformation of
the first order.
Radical environmentalists appear to insist that DDT is a principal contributor of
environmental degradation, and the major cause of death amongst wildlife and
humans. Worse still, many Western people seem to be under the impression that
mosquitoes cannot cause so much human misery as purported, and that malaria is
caused by some kind of plant form of life, or even a virus.
The proponents of DDT, on the other hand, appear to be convinced that DDT is a
saviour of humankind, and argue that the horrors associated with DDT are
exaggerated and baseless, as they are not backed by scientific inquiry. Proponents of
DDT also believe that anything that is overused may kill, even ordinary table salt.
Inthis assignment, both of these positions are scrutinized. On the basis of an historical
overview in Chapter I of the history of the use of DDT, and the emergence of the
debate about DDT in the wake of Rachel Carson's Silent Spring (1962), Chapter 2 is
devoted to an evaluation of seven basic arguments against the use of DDT, while in
Chapter 3 six arguments for the use of DDT are weighed. In Chapter 4 a resolution of
the dilemma is proposed in which a case is made for a limited use of DDT only for
indoor spraying of huts and houses against malaria mosquitoes until such time as a
less dangerous alternative for DDT is found that can be used as effectively in the fight
against malaria. As such, this case is informed by the strong moral conviction that we
cannot allow poor people of colour to die because of a general ban on the use of DDT.
Further research on this ethical debate is encouraged. / AFRIKAANSE OPSOMMING: Hierdie werkstuk is toegespits op 'n in-diepte analise van die pro- en kontra-posisies
in die voortslepende, asook duur debat oor die gebruik van DDT al dan nie in die
bekamping van Malaria. Ek argumenteer dat die dilemma rondom die vraag of DDT
gebruik moet word of nie, aangewakker word deur politieke agendas, sensasie,
oordrywing en foutiewe informasie van die eerste orde.
Radikale omgewingsgesindes dring oënskynlik daarop aan dat die gebruik van DDT
'n hoof-oorsaak is van die agteruitgang van die omgewing, asook 'n primêre oorsaak
van dood onder wild en mense. Erger nog, dit wil voorkom of heelwat Westerse
mense onder die indruk is dat muskiete nie werklik soveel menslike lyding kan
veroorsaak as wat voorgegee word nie, en dat malaria eerder veroorsaak word deur 'n
sekere soort plantvorm van lewe, of selfs deur 'n virus.
Die voorstaanders van DDT, aan die ander kant, is klaarblyklik oortuig dat DDT 'n
redder van die mensdom is, en argumenteer dat die gruwels wat geassosieer word met
DDT 'n grondelose oordrywing is, aangesien dit nie deur wetenskaplike ondersoek
gesteun word nie. Voorstaanders van DDT glo verder dat enige stof wat in oormaat
gebruik word, die dood kan veroorsaak, selfs gewone tafelsout.
In hierdie werkstuk word albei hierdie posisies krities bestudeer en bespreek. Op
grond van 'n historiese oorsig in Hoofstuk 1 oor die gebruik van DDT, en die ontstaan
van die debat oor DDT na aanleiding van Rachel Carson se Silent Spring (1962),
word Hoofstuk: 2 gewy aan 'n evaluasie van sewe basiese argumente teen die gebruik
van DDT, terwyl in Hoofstuk 3 ses argumente vir die gebruik van DDT oorweeg
word. In Hoofstuk 4 word 'n voorstel gemaak vir die resolusie van die dilemma deur
'n saak uit te maak vir die beperkte gebruik van DDT, nl. slegs vir binneshuise
gebruik in hutte en huise teen malaria-muskiete tot tyd en wyl 'n minder gevaarlike
alternatief vir DDT gevind word wat net so effektief sal wees in die stryd teen
malaria. As sulks word hierdie studie gerugsteun deur die sterk morele oortuiging dat
ons nie kan toelaat dat mense van kleur sterf as gevolg van 'n algemene verbod op die
gebruik van DDT nie.
Verdere navorsing oor hierdie etiese debat word aangemoedig.
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The protective effects of Ganoderma extracts from the endocrine disruption of p,p'-DDE on breast cancer cell model.January 2009 (has links)
Qin, Jing. / Thesis (M.Phil.)--Chinese University of Hong Kong, 2009. / Includes bibliographical references (leaves 162-218). / Abstract also in Chinese. / Acknowledgment --- p.i / Abstract --- p.ii / 摘要 --- p.iv / Table of Content --- p.vi / List of Figures --- p.x / List of Tables --- p.xv / Abbreviations --- p.xvii / Chapter Chapter 1 --- Introduction --- p.1 / Chapter 1.1 --- Ganoderma spp --- p.1 / Chapter 1.1.1 --- Introduction of Ganoderma spp --- p.1 / Chapter 1.1.2 --- Bioactivities of Ganoderma spp --- p.3 / Chapter 1.1.3 --- Endocrine system and breast cancer --- p.11 / Chapter 1.1.3.1 --- Estrogen --- p.11 / Chapter 1.1.3.2 --- Estrogen receptors --- p.12 / Chapter 1.1.3.3 --- Estrogen responsive genes --- p.15 / Chapter 1.1.3.3.1 --- pS2 --- p.15 / Chapter 1.1.3.3.2 --- Progesterone receptor --- p.18 / Chapter 1.1.3.4 --- Androgen --- p.21 / Chapter 1.1.3.5 --- Androgen receptor --- p.23 / Chapter 1.1.3.6 --- Androgen responsive gene --- p.24 / Chapter 1.1.3.6.1 --- Transmembrane prostate androgen-induced RNA --- p.24 / Chapter 1.1.3.6.2 --- Uridine diphosphate glucose dehydrogenase --- p.26 / Chapter 1.1.3.7 --- Breast cancer --- p.26 / Chapter 1.2 --- "Endocrine Disruption of p,p '-DDE" --- p.28 / Chapter 1.2.1 --- Introduction of p´ةp '-DDE --- p.28 / Chapter 1.2.2 --- "p,p '-DDE in environments" --- p.29 / Chapter 1.2.3 --- "p,p '-DDE in human body" --- p.32 / Chapter 1.2.4 --- "p,p '-DDE and reproductive system" --- p.33 / Chapter 1.2.5 --- Endocrine disruptor --- p.35 / Chapter 1.2.6 --- "Action mechanism of p,p '-DDE on endocrine system" --- p.37 / Chapter 1.2.7 --- Apoptosis --- p.39 / Chapter 1.3 --- Food therapy against endocrine disruption --- p.41 / Chapter 1.3.1 --- Food therapy and functional food --- p.41 / Chapter 1.3.2 --- Ganoderma as a Functional food --- p.47 / Chapter 1.3.3 --- Cancer prevention by dietary agents --- p.47 / Chapter 1.3.4 --- Hormone therapy --- p.48 / Chapter 1.3.5 --- Hormone-related properties of Ganoderma spp --- p.50 / Chapter 1.4 --- The aim of the study --- p.51 / Chapter Chapter 2 --- Materials and Methods --- p.52 / Chapter 2.1 --- Ganoderma samples --- p.52 / Chapter 2.2 --- Artificial cultivation of Ganoderma spp --- p.54 / Chapter 2.3 --- Molecular identification of Ganoderma spp --- p.55 / Chapter 2.3.1 --- Extraction of genomic DNA --- p.55 / Chapter 2.3.2 --- Gene-specific polymerase chain reaction (PCR) --- p.56 / Chapter 2.3.3 --- Gel electrophoresis --- p.56 / Chapter 2.3.4 --- Purification of PCR amplified product for sequencing --- p.57 / Chapter 2.3.5 --- Cycle-sequencing --- p.57 / Chapter 2.3.6 --- Sequencing --- p.58 / Chapter 2.3.7 --- Sequence analysis --- p.58 / Chapter 2.4 --- Chemical analyses of Ganoderma spp --- p.59 / Chapter 2.4.1 --- Polysaccharide preparations --- p.59 / Chapter 2.4.2 --- Terpene profile --- p.60 / Chapter 2.4.3 --- Fatty acid profile --- p.60 / Chapter 2.5 --- Anti-oxidation activities --- p.61 / Chapter 2.5.1 --- Superoxide radical scavenging assay --- p.61 / Chapter 2.5.2 --- DPPH radical scavenging assay --- p.62 / Chapter 2.6 --- Anti-proliferation effect on human breast cancer cells --- p.62 / Chapter 2.7 --- Hormone-like effects --- p.63 / Chapter 2.7.1 --- E-screen test --- p.63 / Chapter 2.7.2 --- In vitro estrogen receptors (ERs) competitor binding assays --- p.64 / Chapter 2.7.3 --- "Recombinant yeast cell based ER-, AR- and PGR-responsible promoter assays" --- p.65 / Chapter 2.7.3.1 --- Recombinant yeasts --- p.65 / Chapter 2.7.3.2 --- Growth medium for recombinant yeasts --- p.66 / Chapter 2.7.3.3 --- "ER, AR and PGR assays" --- p.67 / Chapter 2.7.3.4 --- β-Galactosidase assay --- p.67 / Chapter 2.7.4 --- Real time PCR --- p.68 / Chapter 2.8 --- Flow cytometry --- p.71 / Chapter 2.9 --- Comet assay --- p.71 / Chapter 2.10 --- DNA microarray --- p.73 / Chapter 2.10.1 --- Total RNA isolation --- p.73 / Chapter 2.10.2 --- cDNA synthesis --- p.73 / Chapter 2.10.3 --- Preparation of labelled cDNA --- p.74 / Chapter 2.10.4 --- cDNA purification --- p.74 / Chapter 2.10.5 --- Oligo GEArray hybridization --- p.75 / Chapter 2.10.6 --- Chemiluminescent detection --- p.76 / Chapter 2.10.7 --- Data analysis --- p.77 / Chapter Chapter 3 --- Results --- p.78 / Chapter 3.1 --- Analysis of Ganderma spp --- p.78 / Chapter 3.1.1 --- Mycelia and fruiting bodies --- p.78 / Chapter 3.1.2 --- Identification of Ganoderma spp --- p.79 / Chapter 3.1.3 --- Chemical properties of samples --- p.80 / Chapter 3.1.4 --- Anti-oxidation activities --- p.90 / Chapter 3.1.5 --- Anti-proliferation effect on human breast cancer cells --- p.90 / Chapter 3.1.6 --- Hormone-like bioactivities --- p.93 / Chapter 3.1.6.1 --- E-screen test --- p.93 / Chapter 3.1.6.2 --- In vitro estrogen receptors (ERs) competitor binding assays --- p.94 / Chapter 3.1.6.3 --- "Recombinant yeast cell-based ER-, AR- and PGR-responsible promoter assays" --- p.95 / Chapter 3.1.6.4 --- ER- and AR-pathway gene expression by real time PCR --- p.97 / Chapter 3.2 --- "Action mechanism of p,p' -DDE" --- p.99 / Chapter 3.2.1 --- E-screen --- p.99 / Chapter 3.2.2 --- In vitro estrogen receptors (ERs) competitor binding assays --- p.101 / Chapter 3.2.3 --- Recombinant yeast cell based ER- and AR-responsible promoter assays --- p.103 / Chapter 3.2.4 --- ER- and AR-pathway gene expression by real time PCR --- p.106 / Chapter 3.3 --- Ganoderma tsugae mycelia extract against p.p' -DDE --- p.109 / Chapter 3.3.1 --- E-screen test --- p.109 / Chapter 3.3.2 --- ER- and AR-pathway gene expression by real time PCR --- p.110 / Chapter 3.3.3 --- Analysis of cell cycle --- p.112 / Chapter 3.3.4 --- Analysis of DNA damage --- p.114 / Chapter 3.3.5 --- Analysis of sub-G1 peak --- p.117 / Chapter 3.3.6 --- DNA damage and apoptosis relative gene expression by real time PCR --- p.120 / Chapter 3.3.7 --- DNA microarray --- p.121 / Chapter Chapter 4 --- Discussion --- p.131 / Chapter 4.1 --- Analysis of Ganoderma spp --- p.131 / Chapter 4.2 --- Effects of p.p´ة-DDE --- p.144 / Chapter 4.3 --- Protective effects of G. tsugae against p.p' -DDE --- p.151 / Chapter 4.4 --- Further investigation --- p.159 / Chapter 4.5 --- Conclusion --- p.160 / References --- p.162
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Sample preparation for pesticide analysis in water and sediments a case study of the Okavango Delta, BotswanaMmualefe, Lesego Cecilia January 2010 (has links)
This thesis presents a first ever extensive analysis of pesticides in water and sediments from the Okavango Delta, Botswana, employing green sample preparation techniques that require small volumes of organic solvents hence generating negligible volumes of organic solvent waste. Pesticides were extracted and pre-concentrated from water by solid phase extraction (SPE) and headspace solid phase microextraction (HS-SPME) while supercritical fluid extraction (SFE) and pressurized fluid extraction (PFE) were employed for sediments. Subsequent analysis was carried out on a gas chromatograph with electron capture detection and analytes were unequivocally confirmed by high resolution mass spectrometric detection. Hexachlorobenzene (HCB), trans-chlordane, 4,4′-DDD and 4,4′-DDE were detected after optimized HS-SPME in several water samples from the lower Delta at concentrations ranging from 2.4 to 61.4 μg L-1 that are much higher than the 0.1 μg L-1 maximum limit of individual organochlorine pesticides in drinking water set by the European Community Directive. The same samples were cleaned with ISOLUTE C18 SPE sorbent with an optimal acetone/n-hexane (1:1 v/v) mixture for the elution of analytes. No pesticides were detected after SPE clean-up and pre-concentration. HCB, aldrin and 4, 4‟-DDT were identified in sediments after SFE at concentration ranges of 1.1 - 30.3, 0.5 – 15.2 and 1.4 – 55.4 μg/g, respectively. There was an increase of pesticides concentrations in the direction of water flow from the Panhandle (point of entry) to the lower delta. DDE, fatty acids and phthalates were detected after PFE with optimized extraction solvent and temperature. The presence of DDT metabolites in the water and sediments from the Okavango Delta confirm historical exposure to the pesticide. However their cumulative concentration increase in the water-flow direction calls for further investigation of point sources for the long-term preservation of the Delta. The green sample preparation techniques and low toxicity solvents employed in this thesis are thus recommended for routine environmental monitoring exercises.
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The history of environment, science and society told by DDT = a discourse and content analysis of the media from the United States and Brazil between 1944 and 2014 = A história do ambiente, ciência e sociedade contada pelo DDT: uma análise de discurso e de conteúdo da mídia dos Estados Unidos e do Brasil entre 1944 e 2014 / A história do ambiente, ciência e sociedade contada pelo DDT : uma análise de discurso e de conteúdo da mídia dos Estados Unidos e do Brasil entre 1944 e 2014Gaissler, Rubia Pereira, 1986- 27 August 2018 (has links)
Orientadores: Aline Vieira de Carvalho, Jansle Vieira Rocha / Tese (doutorado) - Universidade Estadual de Campinas, Instituto de Filosofia e Ciências Humanas / Made available in DSpace on 2018-08-27T17:44:32Z (GMT). No. of bitstreams: 1
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Previous issue date: 2015 / Resumo: Esta tese de doutorado teve como objetivo analisar a cobertura midiática do pesticida DDT desde a sua primeira aparição na mídia, em 1944, até 2014. O objetivo estabelecido foi de identificar as principais narrativas usadas para falar sobre o DDT e as mudanças observadas no discurso referente ao mesmo durante todo o período de tempo acima mencionado. Isto foi atingido observando uma porção selecionada da mídia de dois países que têm um histórico relevante no que diz respeito ao DDT: os Estados Unidos e o Brasil. O primeiro foi escolhido por se tratar de um usuário intenso e um forte defensor da utilização do DDT entre as décadas de 1940 e 1960, e também por ter sido o vórtice de um debate que levou à proibição global do DDT, na década de 1970; o segundo foi incluído na análise para oferecer um contraponto ao primeiro, justificado por uma diferença muito distinta em aspectos culturais, geográficos, econômicos e demográficos. Foram analisadas as revistas Estadunidenses TIME, The New Yorker e Popular Science, e as revistas brasileiras Veja e Superinteressante. O estudo identificou uma virada discursiva única na cobertura da mídia, em 1967, quando DDT deixou de ser visto majoritariamente como benéfico e passou a ser principalmente visto como prejudicial. A análise quantitativa das 711 unidades midiáticas que fizeram parte do conjunto de dados mostrou oscilações na intensidade da cobertura ao longo dos 70 anos estudados, com destaque para um pico entre 1969 e 1971, sendo que tais variações foram interpretadas trazendo o contexto histórico-cultural de cada período abordado e considerando a trajetória do movimento ambientalista, do jornalismo científico e da própria ciência. Adicionalmente, a tese foi estruturada objetivando desmistificar o papel da bióloga norte-americana Rachel Carson na proibição de DDT, investigando sua influência na trajetória do discurso relacionado ao DDT tanto na época em que lançou a obra Primavera Silenciosa, em 1962, quanto observando de que maneiras o retrato da sua figura enquanto símbolo evoluiu nas décadas seguintes até chegar às representações oferecidas no presente / Abstract: This doctoral thesis aimed to analyze the media coverage of the pesticide DDT since its first appearance in the media, in 1944, until 2014. The established objective was to identify the main narratives used to talk about DDT and the observed discourse changes related to it throughout the period of time aforementioned. This was achieved by looking into selected media from two countries that have a relevant history concerning DDT: The United States and Brazil. The first was chosen because it was a heavy user and a strong advocate for DDT use from the 1940s to the 1960s, and also because it was the vortex of a debate that led to the DDT world ban in the 1970s; the second was included in the analysis to offer a counterpoint to the first, justified by a very distinct difference in cultural, geographic, economic and demographic aspects. The United States¿ magazines TIME, The New Yorker, and Popular Science were analyzed, and also the Brazilian magazines Veja and Superinteressante. The research identified a single discourse flip in the media coverage, in 1967, when DDT stopped being majorly seen as beneficial and started being predominantly faced as harmful. The quantitative analysis of the 711 media units that composed the data set showed oscillations in the coverage intensity during the 70 years studied, with a highlight to a peak between 1969 and 1971; such variations were interpreted bringing the historical and cultural context of each period and considering the trajectory of the environmental movement, the scientific journalism and of science itself. Additionally, the thesis was structured aiming to demystify the role of the North American biologist Rachel Carson in the DDT ban, investigating her influence in the DDT discourse trajectory not only when the Silent Spring was published, in 1962, but also observing in which ways her portraying as a symbol evolved in the following decades until reaching today¿s representations / Doutorado / Aspectos Biológicos de Sustentabilidade e Conservação / Doutora em Ambiente e Sociedade
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Effects of DDT on aquatic organisms in the Luvuvhu RiverBrink, Kerry Anne. 17 August 2012 (has links)
Ph.D. / The toxicant dichlorodiphenyl-trichloroethane, commonly known as DDT, is a broad spectrum insecticide and is currently banned in most countries due to its toxic effects. However, in some countries restricted use of DDT has been authorized as an effective vector control within malarial control programmes. South Africa is one such country, where spraying of DDT occurs in three provinces including the Limpopo Province, KwaZulu Natal and Mpumalanga. Specifically in the Limpopo Province, spraying of DDT has been ongoing for almost 56 years within the eastern malaria belt of the province. Despite this long term spraying there is still a scarcity of data regarding DDT and its effects on indigenous aquatic organisms in South Africa. Any research regarding DDT will therefore be of the utmost value. It was in this context that the present study was initiated, which primarily aimed to assess the extent of contamination within DDT sprayed areas in South Africa and the associated effects on indigenous species, whilst identifying techniques that could be used in future monitoring of these areas. This assessment was done in the Luvuvhu River catchment at three reference sites and four exposure sites situated within the areas where indoor residual spraying of DDT is done annually. At these sites the extent of DDT contamination within the water, sediment and biota (using the bioindicator pecies C. gariepinus from only the lentic sites) in the Luvuvhu river was evaluated. The results showed that DDT concentrations were well above recommended levels in all three of the measured phases, with the highest concentrations predominantly observed at the Xikundu weir. This site was particularly impacted by DDT due to a combination of its close proximity to the DDT sprayed areas, concentration accumulation from upstream sources and environmental conditions that accentuated contamination. These elevated levels of DDT did, however, not induce significant quantifiable effects in the bioindicator C. gariepinus or in the fish and macro-invertebrate community structures. Specifically, the effects in the catfish, C. gariepinus, were assessed using a range of biomarkers specific to the endocrine disrupting effects of DDT, including indirect measures of vitellogenin (calcium, zinc, magnesium and alkali-labile phosphate (ALP) that are all present on the VTG molecule in high abundances), gonad-somatic index (GSI), condition factor (CF), analysis of covariance (ANCOVA) manipulated gonads, protein carbonyls (PC) and intersex. Although none of these biomarkers could be significantly correlated with the DDT contaminations, DDT was shown to induce a slight sub-organismal effect by slightly inducing the synthesis of ALP and Ca as well as reducing the gonad mass (shown by GSI and adjusted gonad mass biomarkers) and body condition. In contrast, the fish and macroinvertebrate communities showed no conclusive relationship with DDT contamination, using a variety of methodologies, including informal assessments, univariate diversity indices, multivariate statistics, abundance models, fish response assessment index (FRAI) as well as average score per taxon (ASPT) and Ephemeroptera, Plecoptera and Trichoptera (EPT) richness. In conclusion, it was shown that DDT concentrations within the Luvuvhu River only induced effects at the lower levels of complexity, which highlights the importance of the utilisation of biomarkers to measure more subtle long-term effects as compared to the usage of community level effects.
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Assessment of sperm motility parameters and testicular histology as reproductive indicators for two freshwater fish species in a DDT sprayed area, South AfricaMarchand, Marcelle Jamagne 08 May 2012 (has links)
PhD / An important component of fish health is an optimally functioning reproductive system. The Luvuvhu River Catchment in the Limpopo Province, South Africa, is a tropical, high-risk malaria area where 1,1,1-trichloro-2,2-bis(p-chlorophenyl)ethane (DDT), an endocrine disrupting chemical (EDC), has been used annually since 1945 as a malaria vector control. DDT is known to affect testes morphology and motility of fish sperm. As such, testicular histology and sperm motility (kinematic) parameters were studied as reproductive indicators of the reproductive capacity for two wild, indigenous fish species (Oreochromis mossambicus and Clarias gariepinus) from the currently DDT sprayed area. Three field studies were carried out over two years (2007 – 2008), including two high flow (HF) periods and one low flow (LF) period [HF 1 (March 07), LF (October 07), HF 2 (February 08)]. Both species were sampled from three sites on the Luvuvhu River for testicular histology and computer assisted sperm analysis (CASA), during all three field studies. The sites included a reference site outside the DDT sprayed area, Albasini Dam (AD), and two exposed sites within the DDT sprayed area, Xikundu Weir (XW) and Nandoni Dam (ND). CASA, based on open-source software, was used for the first time in South Africa to assess sperm kinematic parameters of indigenous fish species in field conditions. These included percent motile sperm (% MOT), curvilinear velocity (VCL μm s-1), velocity of an average path (VAP μm s-1), straight line velocity (VSL μm s-1), linearity (LIN %), progression (PROG μm), and average efficiency (AVE. EFF.). Water and sediment samples were collected during all field studies from the three sites for metal and EDC analysis. Controlled laboratory studies were also carried out on the sperm of both species, externally sourced from aquaculture farms equipped to breed and raise fish in toxicant free water. The laboratory studies involved in vitro exposure of spermatozoa to two different, but environmentally relevant, concentrations of both DDT (DDT 1: 0.27 μg L-1; DDT 2: 0.5 μg L-1) and 1,1-dihloro-2,2-bis(p-chlorophenyl)ethylene (DDE) (DDE 1: 0.11 μg L-1; DDE 2: 1.0 μg L-1) with the aim to provide data to support the possible outcomes found in the field studies using CASA. Furthermore, peroxidation of sperm lipids was assayed by production of malondialdehyde (MDA) after in vitro exposure of spermatozoa to DDT and DDE. DDT and its metabolites were found in varying concentrations in the water from all three sites (0.1 μg L-1 – 1.2 μg L-1). Levels of dieldrin (3.5 μg L-1) and lindane (9.4 μg L-1) residues were also found at XW in HF 2. The histological results revealed alterations to testis tissue of both species at all three sites. The testes were assessed through the identification of alterations and an organ index was calculated: Testes Index (IT). The index is indicative of the histological response in the respective tissue type. O. mossambicus at XW had the highest mean IT value during LF (7.45 ± 5.73) and for all field studies combined (5.47 ± 4.63), primarily due to the occurrence of testicular oocytes (intersex), where the frequency of prevalence was 72.73% and 58.82% respectively. These results were statistically higher than the laboratory control (C) group. The CASA results showed statistical differences primarily for O. mossambicus, where motility parameters were lower at XW when compared to AD. Laboratory exposures found a decrease in sperm motility (% MOT) between the control (C) group and the DDT 1, DDE 1 and DDE 2 exposed groups for C. gariepinus. No significant differences were seen for lipid peroxidation (MDA). On the other hand, no significant differences were seen in CASA parameters between the control and exposed laboratory groups for O. mossambicus, but there was an increase in MDA production from the control to the DDT 1 exposure group.
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