Dissertations / Theses on the topic 'Effect of chemicals'
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Filby, Amy Louisa. "Molecular effect pathways of endocrine disrupting chemicals in fish." Thesis, University of Exeter, 2006. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.439828.
Full textDelacruz, C. Ligia. "The effect of natural toxicants and other chemicals on the kidney." Thesis, University of Surrey, 1988. http://epubs.surrey.ac.uk/847359/.
Full textQuinn, Amie L., and University of Lethbridge Faculty of Arts and Science. "The impacts of agricultural chemicals and temperature on the physiological stress response in fish." Thesis, Lethbridge, Alta. : University of Lethbirdge, Faculty of Arts and Science, 2007, 2007. http://hdl.handle.net/10133/676.
Full textix, 137 leaves : ill. ; 29 cm.
Li, Jing Adela, and 李晶. "Temperature-dependent toxic effects of selected chemicals on marine organisms." Thesis, The University of Hong Kong (Pokfulam, Hong Kong), 2014. http://hdl.handle.net/10722/211051.
Full textpublished_or_final_version
Biological Sciences
Doctoral
Doctor of Philosophy
Coberly, Samantha W. "The effect of household chemicals on deciduous and permanent tooth class." Thesis, Wichita State University, 2013. http://hdl.handle.net/10057/6807.
Full textThesis (M.A.)--Wichita State University, Fairmount College of Liberal Arts and Sciences, Dept. of Anthropology
Turan, Nahid. "The effect of plasticisers and related chemicals on sulphate supply enzymes." Thesis, University of Birmingham, 2006. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.433746.
Full textHoward, Samuel Clarence. "The effect of three holding tank chemicals on anaerobic wastewater treatment." Thesis, Virginia Tech, 1988. http://hdl.handle.net/10919/45158.
Full textMaster of Science
Reed, Susan, of Western Sydney Hawkesbury University, and of Science Technology and Environment College. "Development of method to assess skin contact to chemicals." THESIS_CSTE_XXX_Reed_S.xml, 2001. http://handle.uws.edu.au:8081/1959.7/611.
Full textDoctor of Philosophy (PhD)
Montambault, François. "The use of Hoe-39866 as a potato-top desiccant /." Thesis, McGill University, 1988. http://digitool.Library.McGill.CA:80/R/?func=dbin-jump-full&object_id=61703.
Full textWeyand, Eric Henry. "The metabolic fate of benzo [a] pyrene in vivo." Diss., Virginia Polytechnic Institute and State University, 1986. http://hdl.handle.net/10919/77786.
Full textPh. D.
Tomic, Tjasa. "Functionalised cellulosic materials for hydrolysis free reactive dyeing and the fixation of effect chemicals." Thesis, University of Manchester, 2009. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.498845.
Full textSeggio, Joseph A. "Chronic Ethanol Modulated Photic and Non-photic Phase Responses in Syrian Hamster and C57BL/6J Inbred Mouse." Fogler Library, University of Maine, 2009. http://www.library.umaine.edu/theses/pdf/SeggioJA2009.pdf.
Full textDwyer, Suzanne. "Effects of Neonatal Clomipramine Treatment on Photic and Non-Photic Circadian Phase Shifting in Rats." Fogler Library, University of Maine, 2000. http://www.library.umaine.edu/theses/pdf/DwyerSM2000.pdf.
Full textAmoako, Daniel Kwasi. "Cyclopiazonic acid changes the mode of excitation-contraction couplingin acetylcholine-stimulated bovine tracheal smooth muscle." Thesis, The University of Hong Kong (Pokfulam, Hong Kong), 1996. http://hub.hku.hk/bib/B3121387X.
Full textYeung, Chiu Wai. "Neurotoxicological effects of 2,3,7,8-tetrachlorodibenzo-p-dioxin on cultured neurons." HKBU Institutional Repository, 2004. http://repository.hkbu.edu.hk/etd_ra/529.
Full textLi, Yuhong, and n/a. "Effect of alcohol exposure in early gestation on brain development." University of Otago. Department of Anatomy & Structural Biology, 2007. http://adt.otago.ac.nz./public/adt-NZDU20070502.100319.
Full textWorsham, Jessica Nicole. "5-HT3 Receptor Ligands and Their Effect on Psychomotor Stimulants." VCU Scholars Compass, 2008. http://scholarscompass.vcu.edu/etd/1054.
Full textChan, Sai Yen Victor, and 陳世欽. "Effect of homocysteine on nitric oxide production in cardiomyocytes." Thesis, The University of Hong Kong (Pokfulam, Hong Kong), 2001. http://hub.hku.hk/bib/B31970321.
Full textNongauza, Sinethemba Aubrey. "An investigation of the effect of co-solvents on the hydrothermal liquefaction of microalgae biomass." Thesis, Nelson Mandela Metropolitan University, 2015. http://hdl.handle.net/10948/21667.
Full textHolcroft, Joanna (Joanna Mary Steward). "Effect of Anolyte on broiler performance." Thesis, Stellenbosch : Stellenbosch University, 2003. http://hdl.handle.net/10019.1/18708.
Full textENGLISH ABSTRACT: A farm in Zimbabwe (Farm A) obtains its water for tbe poultry operations from tbe Makavusi River that is heavily contaminated with bacteria and performance results are thereby reduced. Anolyte is a Russian invention that claims to have bactericidal effects that could be beneficial to broilers. The aim of this research is to investigate the effect of Anolyte on production profits of broilers given water of poor quality by carrying out a number of trials. Trials that were conducted are basic in vitro tests on Anolyte within the laboratory, water analysis on water supply to the broiler section (both chemical and bacteriological), and a detailed trial within an experimental trial site comparing broiler performance results with different chemical water treatments and different dilutions of Anolyte. Broiler chicks from different hatcheries (Hatchery A and Hatchery B) were also compared. Performance results were based on growtb rate, mortality, feed conversion ratios (FCR), performance efficiency factors (PEF) and profit margin comparisons. Results showed that in tbe laboratory, Anolyte had an antibacterial activity. In the broiler performance trial on Hatchery B broilers, the live weights at forty two days of age in broilers given 15% Anolyte differed from other treatments (P<0.05) other than 10% Anolyte (P > 0.05). However, the FCR and mortalities did not differ (P > 0.05) between treatments. In the trial on Hatchery A broilers to 42 days of age, growth rates in broilers given 15% Anolyte differed from tbe control, Chematron and 20% Anolyte (P < 0.05). However, the FCR and mortalities did not differ between (P>0.05) treatments. In comparing chicks from different hatcheries, Hatchery B broilers differed (P < 0.05) from Hatchery A broilers in live weights at 42 days on 10% Anolyte, 15% Anolyte and on Chematron treatments. However, tbe cumulative mortalities and FCR did not differ (P > 0.05) between the Hatchery B and Hatchery A on any treatment. When comparing profitability, tbe treatment that had the greatest margin in comparison to tbe control (untreated drinking water) was 15% Anolyte for both tbe Hatchery B and Hatchery A trials.
AFRIKAANSE OPSOMMING: 'n Plaas in Zimbabwe, (Plaas A) verkry water, vir hul pluimvee bedryf vannuit die Makavusi rivier. Die rivier is swaar besmet met bakterië en as gevolg daarvan verhoed dit dat hulle hul volle opbrengs potential bereik. Anolyte is 'n Russiese uitvindsel wat aanspraak maak daarop dat dit bakteriëdodende effekte besit wat tot die bevordering van slaghoenders kan lei. Die doel van die navorsing is om Anolyte op proef te stel aangaande produksie profyt op slaghoenders waaraan swak kwaliteit water verskaf is. Verskeie toetse is uitgevoer n1. 'n basiese 'in vitro' toets in samewerking met die laboratorium, water ontleding op water wat aan die slaghoender seksies verskaf is (beide chemikalies and bakterieologies) asook 'n intensiewe proefnemeing waarin die verskeie obrengs resultate, van chemikaliese behandelde water en verskillende verdunnings van Anolyte, met mekaar vergely is, in 'n experimetele navorsings eenheid. Slaghoender kuikens van twee verskillende broeihuise (n1. Broeihuis A en Broeihuis B) is ook met mekaar vergelyk. Die resultate is gabasseer op groei tempo, sterftes, voer omsettings verhouding, opbrengs geskikthied faktore asook vergelykings op wins. Laboratorium navorsing het bevestig dat Anolyte wel antibakteriese aktiviteit getoon het. Terwyl in die proefneming op Broeihuis B slaghoenders, het die lewende gewig van hoenders, op 42 dae van ouderdom, waaraan 15% Anolyte verskaf is, verskil van ander behandelings (P<0.05) met die uitsondering van 10% Annolyte (P>0.05). Alhoewel die voer omsetting verhoudings en sterftes nie in die verskillende behandelings verskil het nie. In die proefnemeing op Broeihuis A slaghoenders tot 42 dae van ouderdom, het die ontwikkeling van slaghoenders, waaraan 15% Anolyte verskaf is, verskil van die kontiole, Chematron en 20% Anolyte. Die voer omsettings verhoudings en sterftes het egter geen verskil getoon tussen die verskeie behandelings nie. Resultate van die vergelyking tussen die kuikens uit die twee verskillende broeihuise, het getoon dat die Broeihuis A en Broeihuis B lewensgewigte, op 42 dae van ouderdom, wel met mekaar verskil het met 10% Anolyte, 15% Anolyte sowel as die Chematron behandelings. Daar was egter geen verskil, (P>O.05) tussen die twee tipes aangaande elke tipe se saamgestelde sterftes en die voer omsettings verhoudings, in welke behandeling nie. Die vergelykings op wins het getoon dat die behandeling met die grootste brulo marge, die was van 15% Anolyte in vergelyking met die kontiole (onbehandelde drinkwater) vir beide die Broeihuis A en die Broeihuis B proefnemings.
Wei, Juntong. "Mass spectrometry-based metabolomics to unveil the polybrominated diphenyl ether-47 induced alteration in breast carcinoma." HKBU Institutional Repository, 2019. https://repository.hkbu.edu.hk/etd_oa/661.
Full textLau, Wai Kit Jaeger. "Developmental expression of N-methyl-D-aspartate and gamma-aminobutyric acid receptors in the rat basal ganglia." HKBU Institutional Repository, 2004. http://repository.hkbu.edu.hk/etd_ra/535.
Full textLam, Wai Chi Rebecca. "Expression of metabotropic glutamate receptors in the rat striatum during postnatal development." HKBU Institutional Repository, 2003. http://repository.hkbu.edu.hk/etd_ra/528.
Full textKile, Joanna L. (Joanna Le). "The Reproductive Consequences of Carriers of Methylenebisacrylamide-Induced Balanced Reciprocal Translocations in Mus Musculus." Thesis, University of North Texas, 1989. https://digital.library.unt.edu/ark:/67531/metadc500402/.
Full textShubat, Pamela Jane. "Monocrotaline toxicity and pulmonary arteries." Diss., The University of Arizona, 1988. http://hdl.handle.net/10150/184533.
Full textCastillo-Ruiz, Priscila. "Plant activation of different chemicals by tobacco and brassica cell cultures, using the plant cellmicrobe coincubation assay." Thesis, McGill University, 1990. http://digitool.Library.McGill.CA:80/R/?func=dbin-jump-full&object_id=39239.
Full textOmami, Elizabeth Nabwile, of Western Sydney Hawkesbury University, of Agriculture Horticulture and Social Ecology Faculty, and School of Horticulture. "Amaranthus retroflexus seed dormancy and germination responses to environmental factors and chemical stimulants." THESIS_FAHSE_HOR_Omami_E.xml, 1993. http://handle.uws.edu.au:8081/1959.7/66.
Full textMaster of Science (Hons)
Poon, Ming-see Angela, and 潘明施. "Binding of 2[125I]iodomelatonin in the guinea pig spleen: evidence for a direct action of melatonin on themammalian immune system." Thesis, The University of Hong Kong (Pokfulam, Hong Kong), 1994. http://hub.hku.hk/bib/B31233855.
Full textAllison, Edwin. "Effects of seed adjuvants on germination and development of onions." Thesis, Cape Technikon, 2001. http://hdl.handle.net/20.500.11838/2000.
Full textOnion seeds (cultivar Caledon Globe), and soil into which the seedlings were planted, were treated with various adjuvants including fungicides, a seed disinfectant and a soil sterilant, as well as soil-applied growth stimulants to determine the effect of these on germination of seed, the growth of plants and the storage life of onions obtained. Three sets of germination trials were undertaken in petri dishes, and sets of seed was also sown in deep seed trays. A trial planting was made and the crop graded and stored. Seed was also sown in pots in soil obtained from a commercial undertaking where poor germination had been obtained. A portion of this soil was pasteurised and a portion inoculated with Fusarium spp. Growth of these seedlings was then followed by re-sowing in the same pots using seed of additional cultivars.
Chidgey, Laura Louise. "An integrated approach to unravel the effect pathways of endocrine disrupting chemicals on the developing zebrafish, Danio rerio." Thesis, University of Exeter, 2008. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.496171.
Full textSandoval, Mojica Andres Felipe. "Antifeedant effect of commercial chemicals and plant extracts against Schistocerca americana (Orthoptera: Acrididae) and Diaprepes abbreviatus (Coleoptera: Curculionidae)." [Gainesville, Fla.] : University of Florida, 2009. http://purl.fcla.edu/fcla/etd/UFE0024748.
Full textMiller, Lana L., and University of Lethbridge Faculty of Arts and Science. "The effects of selenium on the physiological stress response in fish." Thesis, Lethbridge, Alta. : University of Lethbridge, Faculty of Arts and Science, 2006, 2006. http://hdl.handle.net/10133/397.
Full textxiii, 150 leaves ; 29 cm.
Mayles, Karen Marie 1957. "Chemical regulation of growth and fruit maturity of Vitis vinifera 'Flame Seedless' using hydrogen cyanamide." Thesis, The University of Arizona, 1987. http://hdl.handle.net/10150/276605.
Full textDann, Andrea B. "The effects of triclosan, 2,4-D, and their by-products on the adrenocortical cells of rainbow trout." Thesis, Lethbridge, Alta. : University of Lethbridge, Dept. of Biological Sciences, c2011, 2011. http://hdl.handle.net/10133/3154.
Full textix, 139 leaves : ill. ; 29 cm
Belayneh, Teferi Yeshitela. "Effect of cultural practices and selected chemicals on flowering and fruit production in some mango (Mangifera indica L.) cultivars." Pretoria : [s.n.], 2004. http://upetd.up.ac.za/thesis/available/etd-01142005-085139.
Full textAlm, Therese. "Characterization of retention chemicals and their effect on the paper forming process on machine PM4, Billerud Korsnäs Gävle Mill." Thesis, Örebro universitet, Institutionen för naturvetenskap och teknik, 2021. http://urn.kb.se/resolve?urn=urn:nbn:se:oru:diva-93424.
Full textDavison, Elizabeth L. 1947, and Elizabeth L. 1947 Davison. "Caesalpinia pulcherrima, Calliandra californica, and Justicia specigera: Chemical and environmental regulation of their growth and development." Thesis, The University of Arizona, 1989. http://hdl.handle.net/10150/277127.
Full textBull, Kimberly. "Effects of a commercial pentabrominated diphenyl ether mixture on cholinergic parameters in captive mink." Thesis, McGill University, 2006. http://digitool.Library.McGill.CA:80/R/?func=dbin-jump-full&object_id=99325.
Full textHenrico, Daleen (Elsie Magdaleen). "Vergelyking tussen die kodlingmot (Cydia pomonella) se fenologiese ontwikkeling in 'n chemies behandelde-, onbehandelde- en organiese boord in die Wes-Kaap." Thesis, Stellenbosch : Stellenbosch University, 2004. http://hdl.handle.net/10019.1/50223.
Full textENGLISH ABSTRACT: Codling moth, Cydia pomonella (L.), infested fluit were collected in a sprayed, unsprayed and an organic orchard. The time of emergence was monitored to see if there was selection for a delayed emergence caused by different treatments. Moths from fruit collected in the sprayed and unsprayed orchards in Desember 2001, had a peak emergence during January 2002 and a smaller peak during February 2002. Moths from fruit collected during February 2002 from an organic orchard, had a peak emergence during February 2002 and an extended emergence from diapause until January 2003. Moths from fluit collected during March 2002 had a peak emergence during November 2002 with an extended emergence in the sprayed orchards until January 2003. Delayed emergence from diapause was observed. Not all the moths from diapause emerged during the first flight, but overlapped with the second flight in December and January.
AFRIKAANSE OPSOMMING: Kodlingmot, Cydia pomonella (L.), geïnfesteerde vrugte is in 'n onbespuite, chemies behandelde en 'n organiese boord versamel. Die tyd van motuitkoms is gemonitor om te bepaal of verskillende behandelings dalk seleksie in die motpopulasie kan veroorsaak ten op sigte van 'n vertraagde motuitkoms. Motte uit vrugte wat in die gespuite boorde in Desember 2001 versamel is, het 'n piek uitkoms in Januarie en 'n kleiner een in Februarie 2002 gehad. Motte uit die ongespuite boord se vrugte, het ook 'n piek uitkoms in Januarie 2002 getoon. Motte uit vrugte wat in Februarie 2002 in 'n organiese boord versamel is, het 'n piek uitkoms in Februarie 2002 gehad, met 'n verlengde uitkoms vanuit diapause vanaf Oktober 2002 tot Januarie 2003. Motte uit vrugte wat in Maart 2002 versamel is, het 'n piek uitkoms in November 2002 gehad. Daar was ook 'n verlengde motuitkoms vanaf diapause by die chemies behandelde boorde tot Januarie 2003. 'n Vertraagde motuitkoms vanaf diapause is waargeneem. Die motte vanuit diapause maak nie almal deel uit van die eerste vlug nie, maar oorvleuelook met motte van die tweede vlug wat gedurende Desember en Januarie in die veld voorkom.
Kolli, Ramya. "Effect of Leaving Ligands of Platinum(II) Diamine Complexes on DNA and Protein Residues." TopSCHOLAR®, 2013. http://digitalcommons.wku.edu/theses/1268.
Full textManglik, Aparna Safety Science Faculty of Science UNSW. "Development of comparitive methods for chemical analysis and in vitro cytotoxicity testing of contaminated sites." Awarded by:University of New South Wales. School of Safety Science, 2006. http://handle.unsw.edu.au/1959.4/25168.
Full textChu, Yu-Hsuan. "Custom Fluorophores for Investigating the Cellular Uptake Mechanisms and Side-Effects of Pharmaceuticals." PDXScholar, 2015. http://pdxscholar.library.pdx.edu/open_access_etds/2343.
Full textLeduc, Frédéric. "Linking the neuropeptide annetocin with reproductive success of the earthworm Eisenia fetida in two natural soils amended with the wood preservatives chromated copper arsenate (CCA) and alkaline copper quaternary (ACQ)." Thesis, McGill University, 2004. http://digitool.Library.McGill.CA:80/R/?func=dbin-jump-full&object_id=82274.
Full textZhang, Qian Amy, and 張倩. "Ecotoxicities and ecological risks of irgarol 1051 and its related s-triazine compounds in tropical marine ecosystems." Thesis, The University of Hong Kong (Pokfulam, Hong Kong), 2009. http://hub.hku.hk/bib/B41757956.
Full textpublished_or_final_version
Biological Sciences
Master
Master of Philosophy
Smith, Bill J. "The role of epoxidation in 4-vinylcyclohexene-induced ovarian toxicity." Diss., The University of Arizona, 1990. http://hdl.handle.net/10150/185059.
Full textHardin, Joanna, Stacy D. Brown, Phillip Scheuerman, and Kurt Maier. "Imidacloprid Persistence, Mobility, and Effect on Soil Quality and Ecosystem Function." Digital Commons @ East Tennessee State University, 2017. https://dc.etsu.edu/etsu-works/5267.
Full textOtt-Reeves, Ellen (Ellen Theresa). "In Situ Hybridization of 70 kD Heat Shock Protein mRNA in a Rat Model of Ethanol Self-Administration." Thesis, University of North Texas, 1994. https://digital.library.unt.edu/ark:/67531/metadc332564/.
Full textDzedze, Ntombiyesicelo. "Fermentation rate, yeast protein and sensory profiles of wines from fungicide treated Chenin Blanc grapes." Thesis, Cape Peninsula University of Technology, 2018. http://hdl.handle.net/20.500.11838/2820.
Full textFungal diseases in vineyards are one of the main causes leading to economic losses within the viticultural sector and are continuously increasing over years. The most common of these fungal diseases are powdery mildew, downy mildew and grey mould. Commercial fungicides to treat the above-mentioned diseases are available and their usage is regulated under Act 36 of 1947 to comply with Good Agricultural Practises (GAP). However, the application of less-harmful, natural alternative fungicides to control vineyard diseases are currently an important research focus since the demand for organic products by consumers and retail companies are increasing. However, fungicide residues can alter the fermentation process and prevent some biochemical pathways of yeast metabolism involved in phenolic and/or aroma compound production that are critical for sensory quality. Therefore the aim of the study was to investigate the effect of fungicide treatments on the fermentation rate, yeast proteins expressed, aroma compounds released and sensory profile of wines produced. In the study, Chenin Blanc grapes treated with chemical and natural fungicides (1x treatment and 2x treatment) under Good Agricultural Practises (GAP) were used to produce small-scale wines and laboratory-scale fermentations. Laboratory-scale fermentations were conducted in duplicate using the commercial Saccharomyces cerevisiae (S. cerevisiae) Active Dry Wine Yeast (ADWY) strains VIN 13 and VIN 7. The fermentations were monitored by frequently weighing until they stabilised (CO2 weight loss). Small-scale wines were produced using the commercial S. cerevisiae ADWY strain VIN 13 only. Wines were made according to the standard Nietvoorbij experimental winemaking procedure. At the end of fermentation, lees samples were plated onto Yeast Extract Peptone Dextrose (YPD) agar and colonies grown were subjected to CHEF gel electrophoresis to confirm that the S. cerevisiae yeast strain inoculated at the beginning of the fermentation completed it. Moreover, fermenting wine samples, collected at the start (lag phase) and at end of fermentation (stationary phase), were subjected to protein extraction, quantification and characterisation in order to investigate fermenting wine yeast proteins. Furthermore, the final wines were subjected to chemical analyses as well as measurement of aroma enhancing metabolites (esters, higher alcohols, fatty acids and thiol compounds) using GC – FID and MS. Additionally, duplicate samples of the wines were evaluated sensorially by a trained panel of 12 winemakers and researchers, using an unstructured line scale. Wines were compared to the control wine according to visual (colour), flavour (tree fruit, tropical fruit, and wine foreign), taste (body mouthfeel, acidity) and overall quality. The data collected from the study was statistically analysed using a two-way analyses of variance (ANOVAs) and subject to a multiple factor analysis (MFA). From the results obtained in the above study, it was concluded that yeast strains used for winemaking completed the fermentations at a similar rate to their respective controls. In addition, small-scale cellar fermentations showed that fungicide treatments (1x treatment and 2x treatment) compared to the controls had no notable negative effects on wine aroma and sensory profiles although differences were observed in the proteins expressed after the fermentation. Overall, the fungicide treatments did not negatively affect the yeast performance, yeast protein expressed, aroma compounds released and sensory profiles of the wines produced. Further studies are recommended on other white as well as red wine grape cultivars to fully assess the effects of the fungicides.
Dean, Timothy Neal. "The immunotoxic effects of aldicarb." Thesis, Virginia Tech, 1990. http://hdl.handle.net/10919/41612.
Full textGola, Nontuthuzelo Pearl. "A comparison of biomarkers in assessing the combined effects of pesticide mixtures on non-target soil invertebrates." Thesis, Stellenbosch : University of Stellenbosch, 2004. http://hdl.handle.net/10019.1/16327.
Full textENGLISH ABSTRACT: Agricultural environments are usually contaminated with mixtures of antropogenically introduced chemicals as a result of pesticide spraying, which can affect beneficial, nontarget soil invertebrates, such as earthworms negatively. Most studies on mixture toxicity have focused on interactions of chemicals with similar structures and mechanisms. However, chemical mixtures may occur as conglomerates of diverse structures and toxicological mechanisms in the environment. This study was aimed at assessing the effects of pesticides singly, and in a mixture, on earthworms, using lifecycle parameters (growth and reproduction) and biomarkers (neutral red retention (NRR) assay and acetylcholinesterase (AChE) inhibition) as endpoints. Thus, to determine whether any interactions occurred between the pesticides as shown by the measured endpoints. Another aim was to validate the use of the chosen biomarkers for assessing mixture toxicity. The pesticides used were from three groups: organophosphates, heavy metal-containing pesticides and pyrethroids. From these three groups, four of the most commonly used pesticides in the orchards and vineyards of the Western Cape, South Africa, were chosen, namely chlorpyrifos (organophosphate), azinphos-methyl (organophosphate), copper oxychloride (heavy metal-containing fungicide) and cypermethrin (pyrethroid). Earthworms were exposed in the laboratory to a range of concentrations of chlorpyrifos and copper oxychloride singly, and in 1:1 mixtures of these pesticides in artificial soil, for four weeks. After the exposure period, the biomass change was determined as measure of growth, and cocoon production, hatching success and number of hatchlings per cocoon were determined as measures of reproduction. Growth (biomass change) and reproduction (cocoon production) were affected by the highest concentration treatment (20mg/kg) of chlorpyrifos, but copper oxychloride and the mixture of the two pesticides showed no observable effects on lifecycle parameters. Dose related effects on NRR times were however determined for both pesticides and the mixture. Dose related effects on AChE activity were found for chlopyrifos and the mixture of the two pesticides, but not for copper oxychloride. Short-term exposures (48 hours) of earthworms to the following pesticides in artificial groundwater: chlorpyrifos, copper oxychloride, azinphos-methyl, cypermethrin, chlorpyrifos-copper oxychloride, chlorpyrifos -azinphos-methyl and chlorpyrifos-cypermethrin, were done followed by the determination of AChE inhibition. Dose related effects were exhibited on the AChE activity of earthworms exposed to chlorpyrifos, a mixture of chlorpyrifos and copper oxychloride, azinphos-methyl, and a mixture of azinphos-methyl and chlorpyrifos. Copper oxychloride, cypermethrin and the mixture of chlorpyrifos and cypermethrin had no effect on AChE activity. Earthworms died at the highest exposure concentration of the mixture of chlopyrifos and cypermethrin. Results have shown that although the pesticides did not cause observable effects on lifecycle parameters, there were effects at subcellular and biochemical level, as shown by the biomarkers. Mixtures of pesticides, in some instances, affected earthworms differently from their single components, indicating interactions between the pesticides in mixtures, as shown by the measured endpoints. The NRR assay proved to be a good general biomarker of soil contamination, and the AChE activity could also be a valuable tool in assessing the effects of organophosphate mixtures and mixtures of organophosphates and pesticides from other groups.
AFRIKAANSE OPSOMMING: Nie-teiken organismes, soos erdwurms, word negatief beïnvloed deur mengsels van antropogeniese chemikalieë in landbou-omgewings. Die meeste studies wat handel oor die toksisiteit van chemiese mengsels het tot dusver gefokus op chemikalieë van dieselfde aard en met dieselfde meganismes van werking. Mengsels van chemiese stowwe kan egter as konglomerate van 'n verskeidenheid strukturele eienskappe en met verskillende toksiese meganismes in die omgewing aangetref word. Tydens die studie is gepoog om die effekte van enkel pestisiede sowel as mengsels daarvan op erdwurms te bestudeer, deur van lewensloop kenmerke (groei en voortplanting) en biomerkers (neutraalrooi retensietyd - NNR en inhibisie van asetielcholienesterase -AChE) as eindpunte gebruik te maak. 'n Verdere doel van die studie was om vas te stel of daar enige wisselwerkings tussen die verskillende pestisiede plaasvind, soos aangetoon deur die gemete eindpunte, en verder ook om die gebruik van die gekose biomerkers as maatstawwe van mengseltoksisiteit te evalueer. Die pestisiede wat gebruik is, is van drie verskillende groepe afkomstig: organofosfate, swaarmetale en piretroiede. Van hierdie drie groepe is vier van die pestisiede wat vry algemeen in boorde en wingerde in die Weskaap, Suid-Afrika, gebruik word, geïdentifiseer. Hierdie stowwe is chlorpyrifos (organofosfaat), azinphos-metiel (organofosfaat), koperoksichloried (swaarmetaalbevattende fungisied) en sipermetrien (piretroied). Erdwurms is in die laboratorium aan 'n reeks konsentrasies van chlorpyrifos en koperoksichloried as enkel toksikante en as 1:1 mengsels in kunsmatige grond, vir vier weke blootgestel. Voor en na die blootstellingsperiode is die biomassa van die wurms, as maatstaf van groei, bepaal en kokonproduksie, uitbroeisukses en getal nakomelinge per kokon bepaal as maatstawwe van voortplantingsvaardigheid. Groei (biomassaverandering) en voortplanting (kokonproduksie) is beinvloed deur behandeling met die hoogste konsentrasie (20 mg/kg) chlorpyrifos, terwyl geen effek van koperoksichloried of die mengsel van hierdie twee pestisiede gevind is nie. Daar is gevind dat beide die pestisiede, enkel en in die mengsel, die NRR tye beinvloed het. Die AChE aktiwiteit is beinvloed deur chlorpyrifos en die mengsel, maar nie deur die koperoksichloried nie. Korttermyn blootstellings van erdwurms (48 uur), in kunsmatige grondwater, van erdwurms aan chlorpyrifos, koperoksichloried, azinphos-metiel en sipermetrien as enkel toksikante en mengsels van chlorpyrifos-koperoksichloried, chlorpyrifos-azinphos-metiel en chlorpyrifos-sipermetrien, is gedoen en gevolg deur die bepaling van AChE inhibisie. Koperoksichloried, cypermetrien en die chlorpyrifos-sipermetrien mengsel het geen waarneembare effek op die AChE aktiwiteit gehad nie ?????. Die erdwurms wat blootgestel is aan die hoogste konsentrasie in die mengsel van chlorpyrifos-sipermetrien het doodgegaan. Die resultate het getoon dat die pestisiede nie in die korttermyn die lewensloopkenmerke in enige waarneembare mate geaffekteer het nie maar daar was effekte op sellulêre en biochemiese vlakke soos aangetoon deur die biomerkers. Sommige mengsels van die pestisiede het die erdwurms verskillend van die enkelstowwe geaffekteer. Daar het dus wisselwerking tussen sommige van die pestisiede wat in mengsels aangewend is, plaasgevind, soos aangetoon deur die gemete eindpunte. Die NRR toets, as breë-spektrum biomerker was 'n goeie maatstaf van kontaminasie in grond en daar is aanduidings dat die AChE aktiwiteit, as 'n spesifieke biomerker, 'n nuttige maatstaf kan wees om die effekte van organofosfaatmengsels en mengsels van hierdie chemiese groep en die van ander chemikalieë aan te toon.