No description available.

The introduction of lux genes, able to express bioluminescence, into terrestrial bacteria enabled the optimisation of a bioluminescence-based bioassay that was environmentally relevant. Individual assay parameters such as growth phase, cell washing, lyophilisation, pH tolerance and temporal response to a range of metal and xenobiotic pollutants were evaluated. The effects of a range of pollutants upon the metabolic response of the lux-marked organisms were assessed using declines in bioluminescence. The lux -based bioassay proved more sensitive to the sub-lethal effects of metal pollutants than tests relying on culturability. Uncontaminated soils were spiked with metal and xenobiotic solutions both as single pollutants and in combination with other contaminants. Relative toxicity of metal and xenobiotic pollutants in soil systems were investigated using ecotoxicity assays based upon lux-marked constructs of Rhizobium leguminosarum biovar trifolii (an important associative nitrogen fixer) and the respiration of the microbial community. The lux-marked bioassay proved to be more sensitive than the community microbial assay to the presence of multiple contaminants at sub-lethal concentrations. The relative toxicities of metal and organic xenobiotic compounds were shown to be time dependent and better represented using chronic assaying of lux-marked microorganisms. Following a field trial involving the application of paper mill sludge to land and subsequent crop failure a rapid diagnosis of soil pollutants was required. A suite of ecotoxicity assays including lux-based bioassays, respirometry and enzyme activity were used to assess the toxicity of paper mill sludge to the soil microbial biomass. The selected lux-marked soil bacteria showed potential for use as rapid, field-based screening techniques to provide early warning of the potential hazards of waste application.

Thesis (M.App.Sc.) - Carleton University, 2005. / Includes bibliographical references (p. 218-225). Also available in electronic format on the Internet.

Soil Washing is a promising alternative treatment method for contaminated site remediation. An industry contaminated site - the OMEX site was selected for the study, and several extraction additives (chelating agent and surfactant) were used to investigate the application of soil washing for the removal of heavy metals and hydrocarbons. The interactions and transport of the contaminants were studied by bench-scale experiments for both heavy metals and hydrocarbons. Soil characterization was performed before the experiments.The soil characterization indicated that the OMEX soil contained large amounts of Pb, Zn (heavy metal) and total petroleum hydrocarbons (TPH). The contaminant concentrations were 986 mg/kg of Pb, 284 mg/kg of Zn, and 29000 mg/kg of TPH. The contaminated soil was also high in moisture content, organic content and total organic carbon (TOC). From soil analyses on different particle size fractions, most contaminants were concentrated in the fine soil fraction, below 150gm, which constituted about 35% by weight of the contaminated soil.Heavy metal removal by chelating agents was conducted first. The results showed that 3% EDTA solution offered the highest removal efficiency for both Pb and Zn. About 90% of Pb and 65% of Zn were removed by using 3% EDTA solution for 29 hours. The extraction kinetics proved to be slow, reaching equilibrium in a relatively long time (more than 10 hours). In soil washing the solution pH had some effect on the removal of both Pb and Zn with marginally better removals observed at a lower pH. The experimental study indicated that the ratio of washing solution volume to soil weight (LIS) had little effect on the percentage removal of both Pb and Zn.In hydrocarbons removal tests, experiments verified that surfactant solutions can be effective in removing organics from coarse soil fraction, while some amount of surfactants were ++ / adsorbed by fine soil particles. Anionic surfactants such as SIDS exhibited less sorption capacity than nonionic surfactants due to the electrostatic repulsion of the former. 4% SDS solution had the highest TPH removal efficiency for OMEX soil, but the 2% SIDS solution was used as it produced only marginally lower results than the 4%. The percentage removal of TPH was about 78% by using 2% SIDS solution. The TPH removal by SDS solution was observed to be a slow and non-equilibrium process. Higher solution temperature can improve removal efficiency of TPH from OMEX soil. Combined washing with a chelating agent and a surfactant was effective in removing both heavy metals and hydrocarbons. Removals of 78% Pb, 82% Zn and 81% TPH were obtained from OMEX soil in the combination test. However, the TPH concentration in fine soil was still very high after washing and would need further treatment.

The purpose of this work was to estimate metals bioaccessibility in soil samples from 15 city parks in Toronto, Ontario, Canada. Total metals concentrations were analyzed to identify contaminants that exceeded the Canadian Council of Ministers of the Environment (CCME) guidelines for residential/parkland use. Arsenic, barium, cadmium, cobalt, copper, lead, nickel and zinc were of particular interest as they have been known to have major effects on human health. Metal concentrations were below the CCME guidelines except for lead at three of the parks. Lead, copper and cadmium bioaccessibility in the soil samples as determined by an in-vitro physiologically based extraction test (PBET) were relatively high. Based on linear regression analyses there were no significant relationships between total metals and soil properties such as pH and total organic carbon (TOC). Generally there was negative correlation between metal bioaccessibility and TOC and positive correlation between bioaccessibility and soil pH.

Thesis (Ph.D.)--University of Western Sydney, Macarthur, Faculty of Informatics, Science and Technology, 1999. / References: p. 210-233.

Made available in DSpace on 2016-08-31T13:15:07Z (GMT). No. of bitstreams: 1 JorgeLOPF_DISSERT.pdf: 426632 bytes, checksum: 25fc911968ba803bfadd0f3c395126d8 (MD5) Previous issue date: 2010-08-27 / Empresa Brasileira de Pesquisa Agropecuária / The use of mining waste as an alternative source of nutrients assumes significant importance today, due to their potential to reduce production costs and minimize environmental impacts. Thus, this study aimed to evaluate the accumulation and availability of Cd, Pb, Cr and Ni in an Ultisol under the addition of mining waste as an alternative fertilizer for crops. The experiment was conducted in a greenhouse, in desing was the causalized blocks with four replications, in a factorial outline (4 x 3), with four sources (0, 60, 120 and 240 mg kg-1 of K2O) and three sources (RM without application of additional fertilizer, RM with application of additional fertilizers and KCl as reference). The results showed that application from the mine did not promote accumulation of the available concentration of Cd and Pb in soil along the cycles of soybeans, millet and watermelon, however caused increased levels of available Cr and Ni in soil during the three crops succession. For that, The use of mine tailing associated with additional fertilization is recommended as an alternative source of K for annual crops and reducing costs with commercial fertilizers / A utilização do rejeito de mineração como fonte alternativa de nutrientes assume relevante importância nos dias atuais, devido a sua potencialidade de reduzir custos de produção e minimizar impactos ambientais. Sendo assim, objetivou-se neste trabalho avaliar o acúmulo e a disponibilidade de Cd, Pb, Cr e Ni em um Argissolo Acinzentado decorrentes da adição de rejeito de mineração como fertilizante alternativo para culturas anuais. O experimento foi conduzido em casa de vegetação em delineamento inteiramente casualizado com quatro repetições, arranjo fatorial 4 x 3, representando quatro doses (0, 60, 120 e 240 mg kg-1 de K2O) e três fontes (RM sem aplicação de adubação complementar, RM com aplicação de adubação complementar e o KCl, como tratamento referência). Os resultados indicaram que a aplicação do rejeito de mineração não promoveu aumento dos teores disponíveis de Cd e Pb no solo ao longo dos ciclos da soja, milheto e melão; entretanto provocou incremento dos teores disponíveis de Cr e Ni no solo no decorrer dos três cultivos sucessivos. É possível, o uso do rejeito de mineração associado à adubação complementar, como fonte alternativa de K para culturas anuais e reduzir custos com fertilizantes comerciais

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.

A contaminação dos solos por elementos potencialmente tóxicos provoca alterações na estrutura e no funcionamento dos ecossistemas, além de oferecer riscos à saúde pública. Embora os metais pesados ocorram naturalmente, fontes antropogênicas contribuem para o aumento das taxas de redistribuição desses elementos entre os compartimentos do ambiente. O coeficiente de distribuição ou partição sólido-solução (Kd) permite observar a afinidade entre os metais e os colóides do solo. O Kd é peça-chave em muitos modelos para definição de valores orientadores e para previsão de riscos ambientais, e seu valor é dependente das condições edafoclimáticas das regiões onde se assentam os solos. Os valores de Kd de metais pesados ainda não foram determinados para solos da região Amazônica. Nesse estudo objetivou-se determinar os valores de Kd de metais pesados em solos do Estado do Pará. Para tanto foram conduzidos experimentos de adsorção, tipo batch, nos quais foram adicionados 0,5; 1,0; 2,5; 5,0 mg L-1 de Cd, Co, Cr, Cu, Hg, Ni, Pb, e Zn em amostras de 21 solos paraenses. As menores variações nos valores absolutos de Kd foram registradas para o Pb (uma ordem de magnitude - 196,4 a 5.572,5 L kg-1) e para o Cu, Hg e Ni (duas ordens de magnitude 50,5 a 7.368,7; 24,9 a 4.191,6; 4,7 a 524,2 L kg- 1, respectivamente). Variações de três ordens de magnitude foram observadas para: Cd (6,0 a 2.471,9 L kg-1), Co (2,7 a 4.604,1 L kg-1), Cr (2,5 a 1.811,6 L kg-1) e Zn (1,4 a 7.933,0 L kg-1). Obteve-se a seguinte ordem de afinidade: Pb > Cu > Hg > Cr > Cd Co > Ni > Zn. O pH, os teores dos óxidos de Fe e de Mn e a CTC foram os atributos dos solos que mais se correlacionaram com os valores de Kd, que foram inferiores aos estabelecidos por Agências Internacionais e para o Estado de São Paulo. / Soil contamination by potentially toxic elements affects the structure and the functioning of the ecosystems and pose risks to public health. Although heavy metals occur naturally, anthropogenic sources contribute to increased rates of redistribution of these elements between the compartments of the environment. The solid-solution coefficient of distribution or partition (Kd) shows the affinity between metals and soil colloids. Kd is a key componentt in many models for defining and guiding values for prediction of environmental hazards, and its value is dependent on environmental conditions in the regions where they settle the soil. Kd values for heavy metals have not been determined for soils in the Amazon region. In this study, these values were obtained for 21 soils of the State of Pará, Brazil. Adsorption experiments were conducted, type \"batch \", by means of the adition of 0.5, 1.0, 2.5, 5.0 mg L-1 of Cd, Co, Cr, Cu, Hg, Ni, Pb, and Zn to the soils. The small variations in the absolute values of Kd were recorded for Pb (an order of magnitude 196.4 to 5,572.5 L kg-1) and for Cu, Hg and Ni (two orders of magnitude 50.5 to 7,368.7; 24.9 to 4,191.6; 4.7 to 524.2 L kg-1, respectively). Variations of three orders of magnitude were observed for: Cd (6.0 to 2,471.9 L kg-1), Co (2.7 to 4,604.1 L kg-1), Cr (2.5 to 1,811.6 L kg-1), and Zn (1.4 to 7,933.0 L kg-1). We obtained the following order of affinity: Pb > Cu > Hg > Cr > Cd Co > Ni > Zn. The pH, the contents of Fe and Mn oxides, and CEC were the soil attributes that correlated significantly with the values of Kd, which were lower than those set by international and the State of São Paulo, Brazil, agencies.

A contaminação ambiental por metais pesados, entre os quais o cádmio (Cd), níquel (Ni) e zinco (Zn), tanto nos solos cultivados quanto nos produtos agrícolas, demanda constante monitoramento do solo, bem como a quantificação desses elementos nos diferentes órgãos dos vegetais. No manejo da adubação e outras práticas culturais, há contaminação indesejável de metais pesados que se acumulam nos solos ao longo dos anos, podendo causar danos ao crescimento vegetal, produção e/ou qualidade do produto agrícola. Considerando a relevância da problemática dos metais pesados nos sistemas agrícolas, é essencial o conhecimento da ação do Cd, Ni e Zn nos processos metabólicos no cafeeiro. A proposta desta pesquisa foi verificar a influência das aplicações de doses crescentes de Cd, Ni e Zn sobre as características nutricionais, fisiológicas e bioquímicas em plantas de cafeeiro em produção e na qualidade da bebida. Por meio dos parâmetros analisados até 128 dias, a ordem crescente de toxidez é de Ni, Zn e Cd. A distribuição de Cd é maior nos ramos, grãos e folha; Ni nas folhas, ramos e grãos e Zn nos ramos, folhas e grãos. O estado nutricional do cafeeiro não é afetado pela aplicação dos metais, com exceção do nitrogênio e do fósforo, que reduz nas maiores doses de Cd e Zn. A produtividade e qualidade da bebida são reduzidas em razão da aplicação dos metais. / Environmental contamination by heavy metals, including Cd, Ni and Zn, in both cultivated soils and agricultural products, takes constant monitoring of soils and the quantification of these elements in different plant parts. The management of fertilizer and other cultural practices, there are undesirable contamination of heavy metals that accumulate in soils over the years, causing damage to plant growth, production and/or quality of products. Considering the growing concern with heavy metals in agricultural systems is essential research focused on the physiological mechanism of Cd, Ni and Zn in coffee plants. Therefore, to evaluate the translocation of metals to coffee beans, the monitoring and the quantification of these elements in soils and different organs of coffee plants are required. The aim of this study was to evaluate the influence of applications times and rates of Cd, Ni and Zn on the nutritional, physiological and biochemical changes in coffee plants as well as cup quality drink under field condition. According to the results evaluated up to 128 days exposure to metals, the order of increasing toxicity was Ni>Zn>Cd. The distribution of Cd was higher in the plagiotropic branches>grain>leaf; Ni in leaves>stems>grains, and Zn in stems>leaves>grains, respectively. The nutritional status of coffee plants was not affected by the application of metals, except nitrogen and phosphorus, which reduced the highest levels of Cd and Zn. The coffee yield and cup quality drink decreased due to metals exposition.