Marburg, Univ., Diss., 2002. / Computerdatei im Fernzugriff.

Marburg, Universiẗat, Diss., 2002.

Düsseldorf, Universiẗat, Diss., 2001.

Universiẗat, Diss., 2002--Marburg.

As modificações ambientais provocadas pela humanidade, em especial pela agricultura, têm sido motivo de preocupação e estudos por todo o mundo. Nesse sentido, os solos figuram como um dos compartimentos ambientais mais impactados pelo uso de agrotóxicos, produtos amplamente utilizados na agricultura moderna. O objetivo deste trabalho foi avaliar se e como os agrotóxicos Score® 250 EC (i.a. difenoconazol) e Kraft® 36 EC (i.a. abamectina), isolados e em mistura, afetam a flora (germinação e crescimento do tomate - Lycopersicon lycopersicum), as comunidades microbianas do solo (biomassa microbiana em carbono, respiração, quociente metabólico e enzima β-glucosidase) e os enquitreídeos (reprodução de Enchytraeus crypticus em diferentes densidades e a relação trófica entre estes e os microrganismos), ao longo do tempo após a contaminação do solo. Em relação aos parâmetros microbianos, a despeito de algumas variações em decorrência da presença dos agrotóxicos, os indicadores das funções gerais do sistema edáfico não foram grandemente prejudicados, expressando uma redundância funcional. Não obstante, o solo-controle apresentou maior estabilidade em relação às variações dos parâmetros, sugerindo que os microrganismos presentes neste solo apresentaram uma maior robustez e estabilidade ao longo do tempo. Em relação aos testes com E. crypticus, os índices de reprodução não foram significativamente alterados em função da ação dos agrotóxicos, mas ratificou-se a importância dos microrganismos na dieta dos mesmos, haja vista as correlações entre o tamanho das comunidades microbianas e as taxas de crescimento dos enquitreídeos. Com relação ao crescimento e germinação do tomate, puderam ser observados valores maiores de altura e massa seca das plântulas em relação ao controle. Em contrapartida, observou-se uma possível melhor tendência de crescimento das plântulas no solo controle ao longo do tempo. Por fim, considerando a complexa problemática brasileira em relação ao uso de agrotóxicos, reiterou-se a importância do cumprimento das recomendações de aplicação de ambos os agrotóxicos avaliados por parte dos agricultores e recomendou-se a iniciativa de diminuição progressiva da sua utilização. / Environmental changes caused by humanity, especially by agriculture, have been a cause for concern throughout the world. The soils are one of the environmental compartments most impacted by the use of pesticides, which are widely used in modern agriculture. This research aimed at evaluating whether and how the insecticide Kraft® 36 EC (a.i. abamectin) and the fungicide Score® 250 EC (a.i. difenoconazole), isolated and in mixture, affect: a) the soil microbial communities (microbial biomass carbon, respiration, metabolic quotient and β-glucosidase enzyme); b) enchytraeid worms (reproduction of Enchytraeus crypticus in different densities and their trophic relation with microorganisms); and c) the flora (emergence and growth of tomato - Lycopersicon lycopersicum), over 84 days after contamination. The microbial indicators were not greatly impaired and expressed a functional redundancy, despite some variations due to the presence of pesticides. Nevertheless, the control group presented a greater stability than the contaminated ones, suggesting a greater robustness and stability of microorganisms over time, which are important factors for a better quality of the soil. In relation to E. crypticus tests, the importance of microorganisms on their diet was ratified, since positive correlations between the size of microbial communities and the enchytraeids rate of increase were observed. The different densities of E. crypticus were not significantly influenced by the effects of pesticides on the microorganisms. With respect to the growth and germination of tomato, higher values of height and dry mass of the seedlings were observed in contaminated groups. On the other hand, a higher growth tendency of the seedlings in the control soil was observed over time. Finally, considering the complexity of the Brazilian pesticide issue, we emphasize the importance of compliance of the recommendations on pesticides application and reinforce the initiative of decreasing their use.

As modificações ambientais provocadas pela humanidade, em especial pela agricultura, têm sido motivo de preocupação e estudos por todo o mundo. Nesse sentido, os solos figuram como um dos compartimentos ambientais mais impactados pelo uso de agrotóxicos, produtos amplamente utilizados na agricultura moderna. O objetivo deste trabalho foi avaliar se e como os agrotóxicos Score® 250 EC (i.a. difenoconazol) e Kraft® 36 EC (i.a. abamectina), isolados e em mistura, afetam a flora (germinação e crescimento do tomate - Lycopersicon lycopersicum), as comunidades microbianas do solo (biomassa microbiana em carbono, respiração, quociente metabólico e enzima β-glucosidase) e os enquitreídeos (reprodução de Enchytraeus crypticus em diferentes densidades e a relação trófica entre estes e os microrganismos), ao longo do tempo após a contaminação do solo. Em relação aos parâmetros microbianos, a despeito de algumas variações em decorrência da presença dos agrotóxicos, os indicadores das funções gerais do sistema edáfico não foram grandemente prejudicados, expressando uma redundância funcional. Não obstante, o solo-controle apresentou maior estabilidade em relação às variações dos parâmetros, sugerindo que os microrganismos presentes neste solo apresentaram uma maior robustez e estabilidade ao longo do tempo. Em relação aos testes com E. crypticus, os índices de reprodução não foram significativamente alterados em função da ação dos agrotóxicos, mas ratificou-se a importância dos microrganismos na dieta dos mesmos, haja vista as correlações entre o tamanho das comunidades microbianas e as taxas de crescimento dos enquitreídeos. Com relação ao crescimento e germinação do tomate, puderam ser observados valores maiores de altura e massa seca das plântulas em relação ao controle. Em contrapartida, observou-se uma possível melhor tendência de crescimento das plântulas no solo controle ao longo do tempo. Por fim, considerando a complexa problemática brasileira em relação ao uso de agrotóxicos, reiterou-se a importância do cumprimento das recomendações de aplicação de ambos os agrotóxicos avaliados por parte dos agricultores e recomendou-se a iniciativa de diminuição progressiva da sua utilização. / Environmental changes caused by humanity, especially by agriculture, have been a cause for concern throughout the world. The soils are one of the environmental compartments most impacted by the use of pesticides, which are widely used in modern agriculture. This research aimed at evaluating whether and how the insecticide Kraft® 36 EC (a.i. abamectin) and the fungicide Score® 250 EC (a.i. difenoconazole), isolated and in mixture, affect: a) the soil microbial communities (microbial biomass carbon, respiration, metabolic quotient and β-glucosidase enzyme); b) enchytraeid worms (reproduction of Enchytraeus crypticus in different densities and their trophic relation with microorganisms); and c) the flora (emergence and growth of tomato - Lycopersicon lycopersicum), over 84 days after contamination. The microbial indicators were not greatly impaired and expressed a functional redundancy, despite some variations due to the presence of pesticides. Nevertheless, the control group presented a greater stability than the contaminated ones, suggesting a greater robustness and stability of microorganisms over time, which are important factors for a better quality of the soil. In relation to E. crypticus tests, the importance of microorganisms on their diet was ratified, since positive correlations between the size of microbial communities and the enchytraeids rate of increase were observed. The different densities of E. crypticus were not significantly influenced by the effects of pesticides on the microorganisms. With respect to the growth and germination of tomato, higher values of height and dry mass of the seedlings were observed in contaminated groups. On the other hand, a higher growth tendency of the seedlings in the control soil was observed over time. Finally, considering the complexity of the Brazilian pesticide issue, we emphasize the importance of compliance of the recommendations on pesticides application and reinforce the initiative of decreasing their use.

Thesis (PhD)--Stellenbosch University, 2011. / ENGLISH ABSTRACT: The terrestrial Oligochaete species Eisenia andrei and Enchytraeus doerjesi were exposed to different concentration series of Cd and Zn, both separately and in mixtures for 28 days in artificial OECD soil at 15, 20 and 25°C. At the end of the four week exposure period, survival and reproduction were assessed in E. doerjesi and survival, reproduction, biomass change, metal uptake and biomarker responses (MTT and comet assays) in E. andrei. Survival results for both E. andrei and E. doerjesi indicated that the lethality of Cd increased at higher temperatures, whereas the opposite was observed for Zn.Cadmium LC50 values were the highest at 15°C and the lowest at 25°C. In the Zn exposures LC50 increased with increasing temperature. Mixture results in both test organisms indicated that mixtures were less lethal than the metals separately. Effects of mixtures on survival, nonetheless, increased with increasing temperature. In the Cd experiment, reproduction in E. andrei was only recorded in the control treatments at the three temperatures investigated. However, the deleterious effect of Zn on the reproduction of both E. andrei and E. doerjesi decreased with increasing temperature and Zn EC50 for reproduction increased with increasing temperature. Results for exposures to mixtures indicated in both test organisms that the interaction between Cd and Zn were antagonistic. In both E. andrei and E. doerjesi, the effect of mixture exposures on reproduction decreased with increasing temperatures. The highest mixture EC50 values for reproduction were found at higher temperature. In E. doerjesi (using reproduction results in MixToxModules) Cd and Zn interactions were dose level dependent at the three temperatures investigated. Antagonism was the predominant interaction at lower mixture concentrations whereas synergism occurred at mixture concentrations equal to or higher than the mixtures’ EC50 values. Biomass loss increased with increasing temperature in the Cd exposures (p 9 0.05) but not in the Zn exposures in E. andrei. In this species mixture results indicated antagonistic interactions between Cd and Zn at all temperatures investigated. The deleterious effect of mixtures on the biomass of E. andrei increased with increasing temperature. When Cd and Zn interactions were further investigated in E. andrei (using biomass results in MixToxModules) it was found that they were dose level dependent at the three temperatures investigated. Antagonism was the predominant interaction at lower mixture concentrations whereas synergism occurred at mixture concentrations higher than the mixtures EC50 values. The assessment of metal uptake in E. andrei revealed a temperature dependent Cd uptake with higher Cd body burdens occurring at higher exposure concentrations and temperatures (p ≤ 0.05). In the case of Zn, although uptake was lower at higher temperature, there was no statistical difference in uptake between exposure concentrations and between temperatures. Mixture results however indicated that in mixture exposures less Cd was accumulated by E. andrei than in single Cd exposures (p ≤ 0.05). Inversely, in mixture exposures more Zn was accumulated by E. andrei than in single Zn exposures (p ≤ 0.05). Biomarker studies revealed that Cd and Zn were both cytotoxic and genotoxic whether in single or mixture exposures. Factorial ANOVA analyses of the effects of temperature and metals on the reduction of MTT by E. andrei indicated that temperature rather than the metals was the most important factor controlling mitochondrial activity (p < 0.001). In both Cd and Zn exposures significant deleterious metal effects on mitochondrial processes were found to increase with temperature (p ≤ 0.01). Mixture exposures indicated decreasing cytotoxicity with increasing temperature (p ≤ 0.05) and possible antagonism between Cd and Zn at cellular level. Results of the comet assay showed that the genotoxic profile of Cd was the opposite of the genotoxic profile of Zn. Cd was less genotoxic at lower temperature and increasingly deleterious at higher temperature while Zn was more genotoxic at lower than higher temperature (p ≤ 0.05). The results of mixture exposures indicated decreasing mixture genotoxicity with increasing temperature and suggested that the interactions between Cd and Zn at molecular level were probably antagonistic. / AFRIKAANSE OPSOMMING: Eisenia andrei en Enchytraeus doerjesi is aan verskillende konsentrasiereekse van Cd en Zn, afsonderlik en in mengsels, vir 28 dae in OECD kunsmatige grond onderskeidelik by 15, 20 en 25°C blootgestel Die volgende eindpunte is aan die einde van die vier weke blootstellingsperiode gemeet: oorlewing en voortplanting (by E. doerjesi) en oorlewing, voortplanting, biomassaverandering, metaalopname, MTT en komeettoetse (by E. andrei). Oorlewingsresultate by beide E. andrei en E. doerjesi het getoon dat toenemende temperatuur die letale toksisiteit van Cd laat toeneem terwyl die teenoorgestelde waar was vir Zn. By die Cd blootstellings was die LK50 waardes die hoogste by 15°C en die laagste by 25°C. By die blootstellings aan Zn het die LK50 waardes toegeneem by hoër temperatuur. Resultate by die mengsels by beide toestspesies het aangetoon dat die mengsels minder letaal was as die afsonderlike metale. Effekte van mengsels op oorlewing het nietemin toegeneem met toenemende temperatuur. By die Cd blootstellings is voortplanting slegs by die kontroles en in die geval van E. andrei by die drie onderskeie temperature ondersoek. Die nadelige uitwerking van Zn op voortplanting by beide E. andrei en E. doerjesi het afgeneem met stygende temperatuur en die Zn LK50 vir voortplanting het toegeneem met toenemende temperatuur. Resultate van die blootstellings aan mengsels het getoon dat die wisselwerking tussen Cd en Zn by beide spesies antagonisties was. By beide spesies het die invloed van die mengsels op voortplanting afgeneem met stygende temperatuur. Die hoogste mengsel LK50 waardes vir voortplanting is by hoër temperature gevind. By E. doerjesi was Cd en Zn wisselwerkings by blootstelling aan mengsels (voortplantingsresultate ondersoek deur van MixToxModules gebruik te maak) dosisvlak verwant by die drie temperature wat ondersoek is. Antagonisme was die oorwegende wisselwerking by laer mengsel konsentrasies terwyl sinergisme voorgekom het by mengsel konsentrasies gelyk aan of hoër as die LK50 waardes van die mengsels. In die geval van die Cd blootstellings by E. andrei het biomassaverlies toegeneem met toenemende temperatuur (p ≤ 0.05) maar nie by die Zn blootstellings nie. Resultate van blootstellings aan mengsels het getoon dat die uitwerking van mengsels op die biomassa van E. fetida toegeneem het met toenemende temperatuur. By die verdere ondersoek van Cd en Zn wisselwerkings, waar gekyk is na dosis verhouding of dosisvlak antagonisme (deur van biomassa resultate in MixToxModules gebruik te maak), is gevind dat Cd en Zn wisselwerkings dosisvlak afhanklik was by die drie temperature wat ondersoek is. Antagonisme was die oorwegende wisselwerking by laer mengselkonsentrasies terwyl sinergisme voorgekom het by mengselkonsentrasies hoër as die mengsel EK50 konsentrasies. Die bepaling van metaalopname deur E. andrei het ’n temperatuurafhanklike opname van Cd getoon met hoër Cd liggaamskonsentrasies by hoër blootstellingskonsentrasies en temperature (p ≤ 0.05). Alhoewel Zn opname laer was by hoër temperatuur was daar geen statisties betekenisvolle verskille in opname tussen blootstellingskonsentrasies of temperature nie. Die bepaling van metaalopname by wurms wat aan mengsels blootgestel is, het getoon dat minder Cd deur E. andrei opgeneem is as waneer die wurms aan Cd as enkelmetaal blootgestel is (p ≤ 0.05), Daarteenoor het die teenoorgestelde gebeur in die geval van Zn, Meer van die metaal is opgeneem wanneer E. andrei aan mengsels blootgestel is as aan die enkelmetaal. Biomerkerstudie het getoon dat Cd en Zn beide sito- en genotoksies kan wees ongeag of dit as enkelmetale of in mengsels toegedien is. Faktoriale ANOVA analises van die effekte van temperatuur en metale op die verlaging van MTT by E. andrei het getoon dat temperatuur ’n belangriker faktor was as metaalbesoedeling by die kontrole van mitochondriale aktiwiteit. (p ≤ 0.001). By beide Cd en Zn blootstellings was daar in elk geval statisties betekenisvolle metaaleffekte op mitochondriale prosesse met toename in temperatuur (P ≤ 0.01). By blootstellings aan mengsels is gevind dat sitotoksisiteit afgeneem het met toenemende temperatuur (p ≤ 0.05) asook ’n moontlike antagonisme tussen Cd en Zn op sellulêre vlak. Resultate van die komeettoets het getoon dat die genotoksiese profiel van Cd die teenoorgestelde was as die van Zn. Cd was minder genotoksies by laer temperature en meer en meer skadelik by hoër temperature terwyl Zn meer genotoksies was by laer as by hoër temperature (p ≤ 0.05). Die resultate van blootstlling aan mengsels het laer genotoksisiteit getoon met toename in temperatuur. Dit dui daarop dat wisselwerkings tussen Cd en Zn op molekulêre vlak moontlik antagonisties was.