Tesi: "Soil and vegetable contamination"

1

Alum, Absar. "Control of viral contamination of reclaimed irrigated vegetables by drip irrigation". Diss., The University of Arizona, 2001. http://hdl.handle.net/10150/280675.

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A number of factors have contributed to the interest in reclaimed wastewater irrigation of vegetables. However safety of water as related to fresh cut vegetables has been a paramount concern of responsible agencies, growers and consumers. The objective of this study was to evaluate the risk mitigation potential of subsurface drip irrigation during reclaimed wastewater irrigation. Virus detection methodologies on produce were first optimized. Beef extract (3%) +0.04M sodium pyrophosphate was found to be the most efficient eluent to recover viruses from soil and plant material. The recovery efficiency of poliovirus type l and adenovirus type 40 from Pima clay loam soil ranged from 12--16%, and recoveries from Brazito sandy loam ranged from 58--81%. The recovery efficiencies of poliovirus type 1, adenovirus type 40, MS2 and PRD1 from lettuce ranged from 45 to 70%. The recovery efficiencies of MS2 and PRD1 from tomato fruit were in the range of 90%. Poliovirus type 1, adenovirus type 40, MS2 and PRD1 survived longer in Pima clay loam than in Brazito sandy loam. All enteric viruses remained stable at 4°C suggesting that little virus inactivation occurs during transportation and marketing. Poliovirus type 1 and adenovirus type 40 lost 1 log₁₀ in 11 and 17 days respectively on lettuce at room temperature. Hepatitis A virus lost 2.5 log₁₀ in 50 days on a lettuce head in a greenhouse during the winter season. Tomato, lettuce and cucumber crops were irrigated with virus-seeded water by subsurface and surface drippers. Subsurface drip irrigation resulted in 99% less viral contamination of vegetable leaves as compared to surface drip irrigation. The greatest risk of infection occurs from the outer leaves of lettuce. The risk of infection from consumption of reclaimed wastewater irrigated tomatoes and cucumber was 32% and 72% less than lettuce. The risk of infection from rotavirus by ingestion of vegetables is greater than poliovirus type 1. The risk of infection from subsurface drip irrigated vegetables did not approach the United States Environmental Protection Agency's acceptable annual risk (1:10,000) until the concentration of viruses in the irrigation water reached 100/l. No internal contamination by viruses of the vegetables was observed during their growth. The coliphages PRD1 survived longer than poliovirus type I, adenovirus type 40, and MS2. It would thus appear to be a good model for studying the persistence of those viruses on produce and in irrigated agricultural systems.

2

Santos-Araujo, Sabrina Novaes dos. "Soil-to-plant transfer of heavy metals and an assessment of human health risks in vegetable-producing areas of São Paulo state". Universidade de São Paulo, 2015. http://www.teses.usp.br/teses/disponiveis/11/11140/tde-30042015-152533/.

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While contaminated food products are known to be a leading source of exposure to potentially toxic elements (PTEs), for the general population, few studies have been carried out to examine PTEs levels in soils and plants in wet tropical regions such as Brazil. While the most commonly used index for estimating PTEs accumulation in vegetables and the subsequent exposure to humans who eat them is the bioconcentration factor (BCF) - the ratio between the concentration of metals in the edible portions of produce and their total concentration in soils - the BCF does not provide an adequate description of soil-to-plant metal transfers. A better understanding of such transfers requires information about the soil attributes that influence the availability of PTEs to plants. The state of São Paulo (SP) is the largest consumer of vegetables in Brazil, as well as the largest and most diversified producer. Studies are therefore needed on PTEs concentrations in soils and vegetables, in order to assess their quality under guidelines established by Brazilian legislation. It is likewise crucial to establish critical limits of these elements in soils, via models that assess risks to human health, based on data that reflect current conditions in the soils of São Paulo. The objectives in this study were: (i) to characterize and to evaluate the relations between the concentrations of Cd, Cu, Ni, Pb and Zn in soils and in vegetables from the \"Green Belt\" of the state of São Paulo, Brazil, taking the limits established by legislation into account; (ii) to develop empiric models to derive appropriate soil screening values and to provide an accurate risk assessment for tropical regions; (iii) to develop proposals for improved human health-based screening values for Cd, Cu, Ni, Pb and Zn in São Paulo soils, using soil - vegetable relations. With the exception of Cd, there was a positive correlation between pseudototais and bioavailable contents of PTEs. Cd and Pb content in plants, moreover, not significantly correlated with any of the variables studied. All models of random forests and trees were good predictors of results generated from a regression model and provided useful information about which covariates were important to forecast only for the zinc concentration in the plant. The soil-plant transfer models proposed in this study had a good performance and are useful for eight of the ten combinations (five metals versus two species). SP data combined with NL data for Cd in lettuce and for Ni and Zn in lettuce and in carrot when pH, organic carbon - OC and clay contents were included in the model. Including such soil properties results in improved relations between PTEs concentrations in soils and in vegetables to derive appropriate screening values for SP State. The model in which pH, OC and clay contents were included gave the most useful results with SP and NL data set combined for Cu, Pb, Zn in lettuce and for Cd and Cu in carrot. Our setup did not work for Ni and for Pb in carrot because the data models gave an inconsistent result and the combination of datasets did not or insufficiently improve the results.
Uma das principais vias de exposição de elementos potencialmente tóxicos (EPT) para a maioria da população é por meio da ingestão de alimentos, mas poucos são os estudos relacionados às concentrações de EPTs em solos e em vegetais de regiões tropicais úmidas, sobretudo no Brasil. O índice mais comumente utilizado para estimar o acúmulo de EPTs em vegetais e a subsequente exposição humana pelo consumo de vegetais é o fator de bioconcentração (BCF), que é a razão entre a concentração de metais em partes comestíveis de hortaliças e da concentração total do metal no solo. Porém, o BCF não descreve adequadamente a transferência solo-planta de metais. Assim, a utilização de relações envolvendo os principais atributos dos solos que influenciam a disponibilidade dos EPTs às plantas pode explicar com mais detalhe as relações solo-planta. O estado de São Paulo é o maior mercado consumidor, além de ser o maior e mais diversificado produtor olerícola no Brasil. Assim, são necessárias pesquisas referentes às concentrações de metais pesados em solos e hortaliças, para avaliação da qualidade dos mesmos em relação aos limites estabelecidos pela legislação. Os objetivos neste trabalho foram: (i) caracterizar e avaliar as relações solo-planta entre as concentrações de Cd, Cu, Ni, Pb e Zn em solos e olerícolas de folhas e raiz no estado de São Paulo, tendo em vista os limites estabelecidos pela legislação; (ii) desenvolver modelos empíricos para poder derivar adequados limites críticos do solo e fornecer uma avaliação de risco precisa para regiões tropicais; (iii) desenvolver propostas para melhorar os limites críticos baseados na saúde humana para Cd, Cu, Ni, Pb e Zn em solos de São Paulo, utilizando relações solo-planta adequadas para as condições tropicais. Com exceção do Cd, houve correlação positiva entre os teores pseudototais e biodisponíveis dos EPTs. Os teores de Cd e de Pb nas plantas, por outro lado, não correlacionaram significativamente com nenhuma das variáveis estudadas. Os modelos de florestas aleatórias e árvores foram bons preditores de resultados gerados a partir de um modelo de regressão e forneceram informações úteis sobre quais covariáveis foram importantes para previsão apenas para o teor de Zn na planta. A aplicação de modelos de transferência solo-planta proposto neste estudo tiveram bom desempenho e foram úteis para oito das dez combinações (cinco metais contra duas espécies). O conjunto de resultados de SP pode ser combinado com o da Holanda usando o modelo em que se incluem pH, teor de carbono orgânico - CO e teor de argila para Cd em alface e para Ni e Zn na alface e na cenoura. O modelo foi mais eficiente com os conjunto de resultados combinados para Cu, Pb, Zn, em alface e para Cd e Cu na cenoura. A abordagem não foi eficiente para Ni e para Pb em cenoura, com resultados incoerentes para os conjuntos de resultados combindados ou separados, para os quatro modelos testados.

3

Diop, Amadou. "Diagnostic des pratiques d'utilisation et quantification des pesticides dans la zone des Niayes de Dakar (Sénégal)". Phd thesis, Université du Littoral Côte d'Opale, 2013. http://tel.archives-ouvertes.fr/tel-00959895.

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L'agriculture urbaine dans la zone des Niayes de Dakar fournit 60% des besoins en légumes de cette région à fort taux d'urbanisation. Les maraîchers de cette zone ont de plus en plus recours aux pesticides pour lutter contre les ravageurs et maladies des cultures. Les objectifs de ce travail sont de tenter de répondre à la problématique suivante : les pratiques d'utilisation des pesticides ont-elles un impact sur la qualité des ressources environnementales dans cette zone? La consommation des produits horticoles et des eaux souterraines de cette zone comporte-t-elle un risque pour les populations? Nous avons tenté de répondre à ces questions par le biais d'enquêtes de terrain et d'analyses. Les résultats des enquêtes ont mis en évidence l'application de diverses matières actives appartenant aux organophosphorés, organochlorés, carbamates et pyréthrinoïdes sur une variété de spéculations. Les pesticides appliqués ne sont pas généralement homologués et certains d'entre eux sont des polluants organiques persistants et donc interdits d'utilisation au Sénégal. Les pratiques d'utilisation (fréquences, quantités appliquées, conditions de stockage, méthodes d'élimination des emballages) ne respectent pas les règles prescrites par les bonnes pratiques agricoles. Les analyses ont porté sur 80 échantillons d'eaux souterraines, 119 de sol, et 175 de légumes, collectés au niveau des sites de Niaga, de Thiaroye, de Cambérène et de Malika sur quatre campagnes. Les résultats montrent des niveaux de contamination environnementale élevés de la zone des Niayes avec la détection de 15 (eaux souterraines et légumes) et de 17 (sol) pesticides sur 21 recherchés. Dans toutes les matrices, les molécules ayant été détectées à des fréquences élevées sont celles qui avaient enregistré des fréquences de citation d'au minimum 6%. Près de 56% des points d'eau ont présenté au moins une substance dont la concentration moyenne est supérieure à la norme de qualité correspondante et 38% ne respectaient pas la norme de concentration totale. Pour les légumes, des pourcentages de non-conformité variant entre 58 et 76% selon les sites ont été obtenus. Les apports journaliers estimés ont montré que près de 80% des quantités de résidus de pesticide ingérables correspondent aux résidus des trois premières classes de pesticides (extrêmement dangereux, hautement dangereux et modérément dangereux) selon l'OMS. Cette observation montre que le risque lié à l'exposition des populations à l'eau et aux aliments contaminés est réel.

4

Scott-Fordsmand, Janeck James. "Biomarkers of soil contamination". Thesis, University of Reading, 1998. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.265176.

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5

Salgado, Maria Antonia Santos Mendes. "The effects of vegetable oil contamination on mussels". Thesis, Bangor University, 1995. https://research.bangor.ac.uk/portal/en/theses/the-effects-of-vegetable-oil-contamination-on-mussels(a001885f-2570-447b-90fb-d4cc6630d1e9).html.

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In this study the effects of the vegetable oils rapeseed, linseed, olive and sunflower oil on mussel performance were investigated. In view of the scarse knowledge of the effects of vegetable oil spills on marine life, unlike petroleum spills which have been extensively studied, this investigation was directed towards an evaluation of the impact of vegetable oil contamination in the marine environment using Mytilus edulis as a bioindicator organism. The growth of mussels, their tolerance to changing salinities and temperatures, their behaviour and vegetable oil metabolism were studied. Fatty acid composition of mussels. microalgae and vegetable oils was also determined. All the vegetable oils studied had an inhibitory effect on the growth of Mytilus edulis, the growth rate of mussels after four weeks of exposure to the oils being 5 times lower than the growth rates of the control mussels. Growth rates were assessed by a photographic method which proved to be practical and provided sufficient precision in detect small increases in growth. Vegetable oils caused mortalities and they changed the fatty acid composition of mussels. Other biological responses of mussels are also affected by sunflower oil exposure: gaping time, tolerance to low salinities and foot extension activity, of which the latter may be of ecological significance. An uptake and accumulation of fatty acids in mussels marked the presence of vegetable oils, however, fatty acid metabolism was only detected after the oils had been removed. The results of this study indicate that contrary to what is believed, vegetable oils should not be overlooked under the argument of their edibility and biodegradability but instead should be included in oil spill contingency planning because they can cause mortality and disrupt the growth of wild and cultured mussels.

6

Rauton, Susannah R. W. "Soil fertility management in organic vegetable production". Connect to this title online, 2007. http://etd.lib.clemson.edu/documents/1193080187/.

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7

Farias, Christyan Paiva. "Fungos promotores do crescimento vegetal e da fitorremediação de metais pesados em combinação com biochar". Universidade Federal de Uberlândia, 2018. http://dx.doi.org/10.14393/ufu.di.2018.713.

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A busca por medidas sustentáveis para melhorar e suprir a demanda por alimentos que o crescimento populacional exige, aliado a escassez de terras produtivas, além do acúmulo excessivo de metais no ambiente devido a atividades como mineração e aplicação de fertilizantes no solo, foram as duas problemáticas que motivaram o presente estudo. O uso de fungos promotores do crescimento vegetal: Beauveria bassiana, Metarhizium anisopliae, Pochonia chlamydosporia, Purpureocillium lilacinum e Trichoderma asperella, pode tanto vir a influenciar o aumento da produtividade como potencializar a fitorremediação de metais pesados no solo. Esses fatos são explicados pela capacidade do consórcio fúngico de sintetizar e induzir as plantas a produzir fitohormônios direcionados para o melhor desenvolvimento das raízes do hospedeiro. O maior desenvolvimento de raízes pode estimular a fitoextração de metais do solo e conferir tolerância das plantas à contaminação. Na intenção de avaliar a influência dos fungos no desenvolvimento das plantas, foram realizados tratamentos das sementes de soja e milho e aplicação na parte aérea da cultura da cana-de-açúcar. Já para analisar a influência desses organismos no processo de fitorremediação de Cu, Zn e Mn em colunas de solos cultivados com Jacaranda mimosifolia D. Don, os fungos foram inoculados no solo e na parte aérea das plantas. Todos os tratamentos tiveram 6 repetições e suas médias foram submetidas à análise de variância e teste de média ao nível de 5% de probabilidade. O consórcio fúngico condicionou o crescimento de raízes de soja e milho, aumentou a colonização micorrízica arbuscular em soja e cana-de-açúcar. No jacarandá, os fungos melhoraram o desenvolvimento de raízes e parte aérea, maior acúmulo de Mn e Zn na planta, melhor translocação de Mn e Zn das raízes para a parte aérea, além de diminuir o estresse fisiológico. Além disso, a aplicação conjunta de fungos e biochar nas mudas proporciona proteção à sua atividade fotossintética e reduz o risco ambiental de contaminação por metais por diminuir o total de Cu, Mn e Zn lixiviado. O biochar foi adquirido por meio da pirólise lenta do resíduo do beneficiamento da madeira de eucalipto e aplicado superficialmente no solo. Com isso, esse estudo mostrou que os fungos utilizados apresentam potencial para colaborar com o aumento da produtividade de culturas comerciais e colaborar com a melhoria na remediação de solos contaminados com íons metálicos.
The search for sustainable measures to improve and meet the demand for food that population growth requires, combined with the scarcity of productive land, in addition to the excessive accumulation of metals in the environment due to activities such as mining and application of soil fertilizers, were the two problems that motivated the present study. The use of fungi plant growth promoters: Beauveria bassiana, Metarhizium anisopliae, Pochonia chlamydosporia, Purpureocillium lilacinum and Trichoderma asperella can both influence on increasing productivity as the phytoremediation of heavy metals in the soil. These facts are explained by the capacity of the fungal Consortium to synthesize and induce plants to produce phytohormone targeted for the better development of the roots of the host. The further development of roots can stimulate phytoextraction of metals from the soil and give plants tolerance to contamination. In order to evaluate the influence of fungi on the development of plants, were done seed treatments of soybeans and corn and application in aerial part of the culture of sugar cane. To analyze the influence of these organisms in the process of phytoremediation of Cu, Zn and Mn in soil columns cultivated with Jacaranda mimosifolia D. Don, fungi were inoculated in soil and aerial part of plants. All treatments had 6 reptitions and their averages were subjected to analysis of variance and average test at 5% probability. The fungal consortium has conditioned the growth of roots of soybeans and corn, mycorrhizal colonization increased in soybeans and sugar cane. In jacarandá, fungi have improved the development of roots and shoots, greater accumulation of Mn and Zn in plant, best of Mn and Zn translocation from roots to shoots, in addition to decrease physiological stress. In addition, the joint application of fungus and biochar in seedlings provides protection to photosynthetic activity and reduces the risk of environmental contamination by metals by decreasing the amount of Cu, Mn and Zn leached. The biochar was acquired through the slow pyrolysis of the eucalyptus wood processing residue and applied superficially to the soil. With that, this study showed that fungi used present potential to contribute to the increased productivity of commercial crops and contribute to the improvement in the remediation of soils contaminated with metal ions.
Dissertação (Mestrado)

8

Mbodji, Mor. "Etude des impacts environnementaux et sanitaires des déchets d’équipements électriques et électroniques (DEEE) au Sénégal : cas de la ville de Dakar". Electronic Thesis or Diss., Lyon, 2021. http://www.theses.fr/2021LYSE1290.

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Les déchets d’équipements électriques et électroniques (DEEE) sont particulièrement problématiques dans le monde. Le but de cette thèse était d’évaluer les effets potentiellement néfastes des déchets d’équipements électriques et électroniques (DEEE) sur la dispersion de métaux dans l’environnement et leur risque pour la santé humaine à Dakar, au Sénégal. Des études ont d’abord porté sur la détermination des métaux dans les sols de quatre sites de recyclage des DEEE à Dakar (Mbeubeuss, Mermoz Pikine et Reubeuss) par les techniques LIBS et fluorescence X portable. Les résultats de ce travail ont montré que tous les sites étudiés ont été contaminés par les éléments tels que Pb, Cr, Fe, Mn et Zn en comparaison avec un site témoin. La répartition des métaux est fortement dépendante du site et donc de l’activité menée. La contamination potentielle de la population à travers la chaîne alimentaire a été évaluée par l’analyse de légumes produits à proximité de la plus grande décharge de déchets DEEE (Mbeubeuss). La spéciation par extraction séquentielle des éléments Sb, Pb, Sr, Cr, Cu Mn et Zn dans les sols maraîchers a montré que les éléments étaient majoritairement présents dans la fraction résiduelle. Cette approche a permis de montrer que les métaux n’étaient pas mobiles et peu biodisponibles pour les plantes. La contamination des éléments métalliques dans deux lots de légumes récoltés dans deux zones maraichères de Mbeubeuss et l’évaluation du potentiel risque sanitaire associé à la consommation de ces produits ont été étudiés. Les résultats de l’analyse du 1er lot ont montré les teneurs du Cu, Cr, Mn, Zn et Fe ont conduit à des niveaux de métaux bas et des indices de risques faibles. Pour le 2ème lot de légumes (plus proche de Mbeubeuss) les concentrations en Cr, Zn et Pb sont plus élevées avec un indice risque lié à la présence de Cr. Les résultats de ce travail ont permis de conclure qu’il existe un potentiel danger sanitaire pour les consommateurs des légumes lié à l’élément Cr, uniquement si ce dernier est sous forme CrVI
Waste electrical and electronic equipment (WEEE) is particularly problematic around the world. The aim of this thesis was to assess the potentially harmful effects of waste electrical and electronic equipment (WEEE) on the dispersion of metals in the environment and their fate to human health in Dakar, Senegal. Studies first focused on the determination of metals in the soils of four WEEE recycling sites in Dakar (Mbeubeuss, Mermoz Pikine and Reubeuss) by LIBS and portable X-ray fluorescence techniques. The results of this work showed that all the sites studied were contaminated by elements such as Pb, Cr, Fe, Mn and Zn in comparison with a control site. The distribution of metals is highly dependent on the site and therefore on the recycling activity. The potential contamination of the population through the food chain was assessed by analyzing vegetables produced near the largest WEEE waste dump (Mbeubeuss). Speciation by sequential extraction of the elements Sb, Pb, Sr, Cr, Cu Mn and Zn in market garden soils showed that the elements were mainly present in the residual fraction. This approach has shown that the metals are not mobile and not very bioavailable to plants. The contamination of metallic elements in two batches of vegetables produced from two distinct market gardening areas near Mbeubeuss and the evaluation of the potential health risk associated with the consumption of these products were studied. The results obtained from the first batch showed the contents of Cu, Cr, Mn, Zn and Fe led to risk indices. For the 2nd batch of vegetables (closer to Mbeubeuss) the concentrations of Cr, Zn and Pb are higher with a risk linked to the presence of Cr. The results of this work led to the conclusion that there is a potential health hazard for consumers of vegetables linked to the Cr element, only if it is present as CrVI

9

Allen, David. "Vegetable Fibre Geotextiles used to Reinforce and Reinstate Contaminated Soil". Thesis, Leeds Beckett University, 2009. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.523682.

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10

Mhlauli, Ntuthuzelo Columbus. "Growth analysis and soil water balance of selected vegetable crops". Diss., University of Pretoria, 2000. http://hdl.handle.net/2263/26200.

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Please read the abstract in the section 00front of this document
Dissertation (M Inst Agrar (Horticulture Science))--University of Pretoria, 2000.
Plant Production and Soil Science
unrestricted

11

Mzini, Loyiso Lloyd. "The effects of greywater irrigation on vegetable crops and soil". Master's thesis, University of Cape Town, 2013. http://hdl.handle.net/11427/6609.

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Research on greywater irrigation has mainly focused attention on the reuse of greywater in relation to its quality and crop biomass but not on quality of edible vegetable crops. Thus a field experiment was established at the Umtata Dam Research Station where combinations of cabbages and onions; spinaches and beetroots; and carrots and lettuce were planted in to coincide with four different planting seasons (from October 2009 to December 2010). Crops were irrigated with greywater generated from bathing and dishwashing. Greywater was collected from a number of households in the vicinity of the Umtata Dam, in the Eastern Cape Province of South Africa. In the field experiment, vegetables were planted in three plots of the same composition of soil properties and then drip irrigated separately either with greywater, potable water, or with diluted greywater at a ratio of 1:1. The greywater quality, yield, aesthetical appeal, plant chemical analysis and soil chemical analysis were measured. Irrigation from diluted greywater showed a significant increase in yield, in the head mass and in appeal of cabbages. Onion yields were significantly higher when irrigated with greywater. Spinach also obtained significantly higher yields when irrigated with greywater, however many leaves from this treatment were infested with leaf-spot disease. Beetroot yield and quality was not affected with greywater irrigation, instead yield was reduced by 47% (4.686 tons/ha). Carrots did not show any significant difference in yield and root girth, but carrots irrigated with potable water were more appealing and longer in length. Lettuce irrigated with dilute greywater was significantly more appealing than other treatments. Sodium (Na) ions were elevated in cabbage, onions and were significantly higher in the case of lettuce and carrots when irrigated with greywater. Crude protein (CP) was observed to be significantly elevated on cabbages and lettuce when irrigated with diluted greywater whereas CP of onions and carrots were significantly lower due greywater irrigation. Significant increases in iron (Fe) were observed on cabbages and spinach when irrigated with diluted greywater, whereas lettuce Fe content was significantly elevated by greywater irrigation. There was no significant difference in cadmium (Cd) caused by irrigating spinach and lettuce with greywater, also those heavy metals that were significantly higher, were within the accepted threshold leaving the conclusion that lower levels of heavy metals posed no health risks to humans. In conclusion, greywater used in this study does not appear to cause an accumulation of salts and heavy metals in plants and soil, which suggests in this instance, that greywater does not pose a threat to plants and soils.

12

Choi, Chung-ming. "Land contamination and its remediation methods : a case study in Hong Kong /". Hong Kong : University of Hong Kong, 1995. http://sunzi.lib.hku.hk/hkuto/record.jsp?B14709156.

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13

Meuli, Reto Meuli Reto Giulio Meuli Reto Giulio Meuli Reto Giulio. "Geostatistical analysis of regional soil contamination by heavy metals /". [S.l.] : [s.n.], 1997. http://e-collection.ethbib.ethz.ch/show?type=diss&nr=12121.

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14

Tsang, Jennifer Arr, e 曾昭雅. "Dioxin contamination in soil: remediation technology and environmental management". Thesis, The University of Hong Kong (Pokfulam, Hong Kong), 2003. http://hub.hku.hk/bib/B31255644.

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15

Sudini, Hari Kishan Huettel Robin Norton. "Soil microbial community structure and aflatoxin contamination of peanuts". Auburn, Ala., 2009. http://hdl.handle.net/10415/1875.

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16

Sjödell, Ingrid. "Spatial Assessment of Soil Contamination through GIS Data Management". Thesis, KTH, Hållbarhet och miljöteknik, 2018. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-236774.

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Spatial data management within the environmental field has a large range of application possibilities and comes with great advantages. In this study methods and technologies for spatial data management of soil contamination has been assessed in Geographical Information Systems (GIS), in order to identify in which way spatial data applications and tools can contribute with valuable information for these type of projects. The spatial assessment has been applied on a case study site in Kagghamra, Stockholm, exposed to high levels of contaminants, arsenic in particular. Subjects that have been evaluated are arsenic contamination distribution pattern, estimation of volume contaminated soil and amount of samples needed for spatial analyses. Furthermore, two versions of an exploratory soil sensitivity estimation model based on site specific ground and landscape parameters as well as literature references have been developed. The data management included large quantities of primary and secondary data of the commination levels as well as geological and ground properties. First hand collected geophysical field data obtained from Electromagnetic (EM) and Induced Polarisation (IP) measurements was also interpreted. The benefits of using geophysical measurements in soil contamination projects has been investigated. In this case the benefits were few due to difficult measuring conditions with disturbance noise. Spatial interpolations with the Natural Neighbour (NN) technique are proven to be useful in transforming point contamination data into continuous layers. From the interpolation surfaces (arsenic distribution map) a variety of information can be extracted, such as a first hand volume estimation of contaminated soil, possibilities of reduction in amount of field sampling or to investigate statistical information and relations to different site specific ground conditions. The soil sensitivity estimation models are combined maps consisting of data layers that are relevant for the arsenic behaviour and interaction in the subsurface. Site specific Model (1) is based the data layers Soil type, Iron level, Soil depth, Slope and illustrates mainly areas exposed to high concentrations of arsenic as high sensitivity areas. The more general, literature supported Model (2) also includes Vegetation cover and Topographic Wetness Index (TWI) and is not related highly to the arsenic distribution in the site area, but could contribute with general implications of sensitive areas if applied on a another, larger site area. Efficient management of large data quantities, economic and time saving benefits from less physical sampling and good representation and visualisation possibilities of the site conditions, as a tool for stakeholder communication and decision-making are the main contributions from the spatial data management.

17

Svendsen, Claus. "Earthworm biomarkers in terrestrial ecosystems". Thesis, University of Reading, 2000. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.326956.

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18

Mohammadi, Kourosh. "Numerical modeling of petroleum contamination in the subsurface soil layer". Thesis, National Library of Canada = Bibliothèque nationale du Canada, 1998. http://www.collectionscanada.ca/obj/s4/f2/dsk1/tape11/PQDD_0005/NQ38727.pdf.

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19

Zhao, Zhenyong. "Biosurfactants enhanced bioremediation of PAHs contamination soil under thermophilic condition". HKBU Institutional Repository, 2007. http://repository.hkbu.edu.hk/etd_ra/822.

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20

Leiva, Soto Andrea S. "Effects of Soil Balancing Treatments on Soils, Vegetable Crops and Weeds in Organically Managed Farms". The Ohio State University, 2018. http://rave.ohiolink.edu/etdc/view?acc_num=osu151514193894181.

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21

Whitfield, Lynn. "Heavy metal tolerance and mycorrhizal colonisation in Thymus polytrichus A. Kerner ex BorbaÌs ssp. britannicus (Ronn.) Kerguelen (Lamiaceae)". Thesis, University of Newcastle Upon Tyne, 2002. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.246685.

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22

Al-Shehry, Jaber Mohammed. "EFFECT OF GUAR GUM ON VEGETABLE TRANSPLANT GROWTH". Thesis, The University of Arizona, 1985. http://hdl.handle.net/10150/275440.

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23

Overstreet, Laura Flint. "RELATIONSHIPS BETWEEN SOIL BIOLOGICAL AND PHYSICAL PROPERTIES IN A LONG-TERM VEGETABLE MANAGEMENT STUDY". NCSU, 2005. http://www.lib.ncsu.edu/theses/available/etd-10312005-033217/.

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Agricultural management decisions that influence biological activity and diversity include tillage, fertilizer and pest-control inputs, and crop rotations. Our research objective was to characterize relationships between biological and physical properties resulting from long-term agricultural management decisions. A nine-year old factorially-designed field experiment was used to examine the effects of tillage (moldboard plow or strip-tillage), input (synthetic fertilizers and pesticides or inputs approved for organic certification programs), and crop rotation (continuous staked tomatoes or 3-year vegetable rotation) on a suite of biological and physical soil parameters. Biological measurements included microbial, nematode, and earthworm community composition, soil respiration and N mineralization potential, enzyme activity, and microbial biomass. Physical property measurements included aggregate stability, bulk density, and pore-size distribution. Biological properties generally responded to all treatment combinations, but tillage provided the strongest treatment effect in most cases. Compared to strip-tillage, tillage consistently yielded significantly lower values for the following biological measurements: total C and N, above-ground biomass, microbial biomass, enzyme activity, soil respiration, N mineralization, some nematode trophic groups, and earthworms. Compared with organic inputs, synthetic inputs consistently induced significantly lower values for the following biological measurements: microbial biomass, enzyme activity, some nematode trophic groups, and soil respiration. An examination of relationships between biological and physical parameters using redundancy analysis revealed that microporosity was the physical property that was most strongly correlated with most biological parameters. Soil organisms responded to our treatments in the following order: tillage > input > rotation.

24

Harrison, Adrian Briscoe. "Hydrocarbon pollution of soil : effects on microbial populations and biomediation methods". Thesis, University of York, 1996. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.362025.

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25

Nolte, Kurt, Mark C. Siemens e Pedro Andrade-Sanchez. "Integrating Variable Rate Technologies for Soil-applied Herbicides in Arizona Vegetable Production". College of Agriculture and Life Sciences, University of Arizona (Tucson, AZ), 2011. http://hdl.handle.net/10150/146756.

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5 pp.
Precision herbicide application is an effective tool for placing soil incorporated herbicides which have a tendency for soil adherence. And while field implementation depends on previous knowledge of soil textural variability (soil test and texture evaluations), site-specific technologies show promise for Arizona vegetable producers in non-uniform soils. Regardless of the method used for textural characterization, growers should keep in mind that textural differences do not change in the short/medium term, so the costs associated with defining texture-based management zones can be spread over many years.

26

Cundiff, Gary Thomas. "Using Arbuscular Mycorrhizae to Influence Yield, Available Soil Nutrients and Soil Quality in Conventional VS. Organic Vegetable Production". TopSCHOLAR®, 2012. http://digitalcommons.wku.edu/theses/1155.

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This research is a two year study on the effects of endomycorrhizae on vegetable production using conventional vs. organic practices. Objective of this study was initiated to determine if mycorrhizae improve yield, available soil nutrients and soil quality from two different fertilizer sources. Measurements were taken on yield, available soil nutrients, and soil quality in comparison of glomalin production and soil loss percentage. Two plant species were chosen, Tomatoes (‘Big Beef’) and Bush Beans (‘Tenderette’). A randomized split block 2 x 3 factorial treatment arrangement was used with two crops and three different inputs: Mo- 0 mycorrhizae, M1- recommended rate, and M2- 2x recommended rate of mycorrhizae. Each mycorrhizal input was replicated three times in both the conventional and organic system. Results show there was no difference in yield based on mycorrhizae additions at any rate. There was a significant yield difference based on conventional production over organic production in tomatoes and snap beans in 2010 and tomatoes in 2011. Possible explanations for yield difference in the organic production system include: different insect controls and a slower release of nutrients from poultry litter. Available soil nutrients were not influenced in the study based on mycorrhizal inputs in inorganic or organic tomato production. Soil available nutrients were significantly influenced in organic tomato when compared to inorganic tomato production at selected sampling dates. Mycorrhizae did not influence soil fertility in inorganic snap bean or organic snap bean production. Soil available nutrients were significantly influenced in organic snap bean when compared to inorganic snap bean production at selected sampling dates. Glomalin production and soil loss percentage were not shown to be significantly different within organic or inorganic treatments based on mycorrhizae inputs. However, glomalin production was shown to be significantly greater in organic production compared to inorganic in 2011. An explanation of this could be due to the use of leaf mulch as organic weed control. Although a numerical decrease was observed in soil loss percentage in organic production compared to inorganic production from the first year to the second, it was not shown to be a significant amount.

27

Payne, Rosara Faith. "Investigation of radiological contamination of soil samples from Idaho National Laboratory". Diss., Online access for everyone, 2006. http://www.dissertations.wsu.edu/Dissertations/Summer2006/r%5Fpayne%5F053106.pdf.

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28

MacDonald, Julian. "Analysis of '1'3'7Cs contamination in soil using in-situ gamma spectrometry". Thesis, Bangor University, 1999. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.297869.

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29

Keatinge, Zoe Alexandra Frances. "Soil contamination in urban Tyneside : a chemical and biological risk assessment". Thesis, University of Newcastle Upon Tyne, 2006. http://hdl.handle.net/10443/233.

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The extent of soil contamination with organic and inorganic pollutants in most urban areas in the UK is largely unknown but due to past and present industrial activity it is likely that pollutant levels are high. Such contamination could have a serious impact on human health. Therefore this thesis set out to examine the extent of soil contamination within Newcastle upon Tyne with a focus on the contribution of an incinerator (Byker) to contamination levels of urban soils. The Byker incinerator is situated in central Newcastle and has been the subject of much media controversy due to the disposal of incinerator ash on local allotments. The current work extended past investigations to see if the incinerator had contributed to general urban soil pollution (heavy metals and dioxins) by aerial deposition and allowed a useful investigation into levels of urban soil contamination in Newcastle. In addition to examining metal and dioxin levels the bioaccessibility (human and bacterial) of pollutants in selected soil samples was estimated and an attempt to develop a human cell based soil toxicity assay made. These measurements permit a preliminary assessment of risk to human health from soil contamination. A total of 163 soil samples were collected based on predicted aerial deposition from the Byker incinerator and analysed for dioxins and heavy metals (As, Cd, Cr, Cu, Hg, Ni, Pb & Zn) content (mg pollutant /kg soil). A high proportion of samples (90/163) had contamination levels above soil guideline values (as proscribed in current UK regulations; CLEA). The highest dioxin levels were South West of the incinerator (1911 ng I-TEQ/kg) and the congener profiles coupled with a detailed historical survey demonstrated that the source of contamination was likely to be an old alkali works and not the incinerator. Overall it was found that the incinerator did not contribute significantly to dioxins found in the urban soils except those in the incinerator plant grounds. Soil metal contamination levels varied but were not related to incinerator deposition. Many samples contained levels of heavy metals well over soil guideline values with the highest values being found for Cu (12,108 mg/kg), Pb (4,134 mg/kg) and Zn (4,625 mg/kg) To determine the potential human health risk associated with heavy metal contaminated soils, selected samples (16) were subjected to two in vitro digestion techniques which simulate the bioaccessibility of metals (Cu, Ni, Pb & Zn) to humans in case of soil ingestion. Only three samples had high levels of metal availability (over SGV's) indicating that these soils should be subjected to further risk assessment. All other samples tested had low metal availability most likely due to a combination of metal speciation, and complexation to soil particles over time. An attempt was made to develop a human cell based system to determine the toxicity of contaminated soil. Using an in vitro system, human liver cells (HepG2's) were exposed to extracts from soils; cytotoxic effects (membrane integrity, metabolic capability and oxidative stress status) and genotoxicity potential (DNA damage) of Cu and Zn were first investigated in order to standardise the biological assays used. Between 0.1 and 10 mg/L Cu caused DNA damage and higher concentrations caused cytotoxicity. Zn was also proven to cause genotoxic effects from O. lmg/L. From 10 mg/L cytotoxic responses occurred and DNA damage could be attributed to cell death. Due to difficulties in sterilising soil extracts and physical damage caused to HepG2 cells by the abrasive nature of soil, it was not possible to elucidate whether metal contaminated soil extracts were capable of causing a cytotoxic or genotoxic response in human liver cells. Finally, the same soil samples were then subjected to a bacterial (lux) biosensor technique to examine soil toxicity. Interestingly, despite the high levels of contamination found, none of the soil samples were found to be toxic to the two Pseudomonas strains used which again indicates a low level of ecosystem risk and suggests that most of the contaminants present are either in a form that is unavailable to living microbes or are complexed to soil particles. In summary, this research has shown that the high level of soil contamination of urban areas in Newcastle is due to past industrial activity and a similar situation is likely in most other urban areas of the UK and internationally. The high cost of remediation means that if contaminated sites are shown to be a potential risk then bioaccessibility of contaminants should be examined in order to provide a more realistic assessment of the need for remediation. This work demonstrates that only a small proportion of urban contaminated sites are likely to require remediation based on bioaccessibility determination measurements.

30

Mo, Jialin. "Soil Amended with Calcium-Magnesium Immobilizing Agent against Natural Arsenic Contamination". Kyoto University, 2019. http://hdl.handle.net/2433/242786.

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31

Knewtson, Sharon Joy Blanton. "Studies in vegetable and high tunnel production on the Central Great Plains". Diss., Manhattan, Kan. : Kansas State University, 2008. http://hdl.handle.net/2097/926.

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32

Hadebe, G. P., e der Westhuizen C. Van. "The impact of soil compaction on the vegetative growth of carrots (Daucus carota, var. Sativas) planted in loosened and unloosened soil in the Eastern Free State". Interim : Interdisciplinary Journal, Vol 4, Issue 2: Central University of Technology, Free State, Bloemfontein, 2005. http://hdl.handle.net/11462/438.

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Published Article
This study focuses on trials conducted on plots in the Leratong and Mpho vegetable gardens in the Eastern Free State. The aim was to investigate the possible impact of soil compaction on the growth of carrots planted on loosened (treated) and unloosened (untreated) soil. Aspects such as sprouting, vegetative length after 14 days of sprouting and diameter, as well as the length and mass of carrots after harvesting, were observed and compared between the treated and untreated carrot plots. Although there was no significant (P>0.05) difference between the two soil management practices applied in all locations, as well as the vegetative growth in the locations, a significant (P<0.05) difference between the length of carrots from the treated and the untreated plots was observed.

33

Fokin, Maria. "Efficiency of soil washing in hydrocarbon removal: the role of temperature, surfactant concentration and soil mineralogy". Doctoral thesis, Urbino, 2020. http://hdl.handle.net/11576/2675698.

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34

Hu, Junli. "Risk assessment and mycorrhizal remediation of cadmium contamination in vegetable farms around the Pearl River Delta, China". HKBU Institutional Repository, 2013. http://repository.hkbu.edu.hk/etd_ra/1484.

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35

Dodds, Heather Anne. "An investigation into vanadium contamination of soil and its effects on plants". Master's thesis, University of Cape Town, 1994. http://hdl.handle.net/11427/17002.

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Bibliography: pages 64-67.
This study constitutes a preliminary assessment of the behaviour of effluent-associated vanadium, and its possible effects on the biotic components of land treatment sites, used for the disposal of liquid industrial wastes from a chemical plant in the eastern Transvaal. A review of the literature showed that although the emission of vanadium into the environment is on the increase, very little information is available regarding its behaviour and impact as an environmental pollutant. This study is therefore important not only in the context of the land treatment operation in question, but clearly in a more universal context as well. The study involved a three-phase approach to the problem. Firstly, vanadium sorption was considered in four soils encountered on the sites in question. Secondly, an investigation was conducted into the potential toxicity of vanadium to relevant plant species. Finally, the potential inhibition of soil biological activity at increasing levels of vanadium was examined, although the results of this experiment were inconclusive.

36

Randima, Livhuwani Priscilla. "Rhizosphere microbial diversity in PAH's contaminated and uncontaminated soil". Pretoria : [s.n.], 2009. http://upetd.up.ac.za/thesis/available/etd-11302009-195201/.

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37

Choi, Chung-ming, e 蔡頌明. "Land contamination and its remediation methods: a case study in Hong Kong". Thesis, The University of Hong Kong (Pokfulam, Hong Kong), 1995. http://hub.hku.hk/bib/B3125312X.

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38

Bundy, J. G. "The use of biological methods for the assessment of oil contamination and bioremediation". Thesis, University of Aberdeen, 1999. http://digitool.abdn.ac.uk/R?func=search-advanced-go&find_code1=WSN&request1=AAIU602050.

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There is a concern that concentration-based targets for soil clean-up are arbitrary, and do not necessarily relate to the environmental threat posed by the residual contamination. The development of sensitive, reliable, and ecologically relevant biological tests for oil-polluted soils would address these problems, and form a valuable complement to chemical analysis. Three biological test systems were chosen for examining the impact of oil contamination on soil microbes: (1) lux-marked bacterial biosensors, (2) Biological carbon source utilization profiles, and (3) phospholipid fatty acid (PLFA) community profiles. This allowed the testing of effects at three different levels of ecological complexity: respectively, single species; culturable bacteria; and eubacteria and eukaryotes. The use of specific bioluminescent biosensors (i.e. with lux genes fused to promoters from hydrocarbon degradation pathways) allowed the rapid detection of different hydrocarbon classes. The bacterial biosensors were optimized for the assessment of hydrocarbon compounds. Development of quantitative structure-activity relationships (QSARs) increased understanding of their responses to hydrocarbons and other petroleum-derived compounds. The three biological methods were then used to monitor the nutrient-assisted bioremediation of oil-spiked soils in two separate microcosm experiments: (1) remediation of four crude oils and one refined oil compared using bacterial biosensors, and (2) effects of diesel on three different soil types, and effects of three refined oils on one soil type, assessed using Biolog and PLFA profiling. All three biological test methods were sensitive to the oil contamination levels applied in the microcosm experiments. Individual species (biosensor tests) gave different responses to different oils; however, the community-level responses showed no differences. The microbial communities of the three different soil types could still be distinguished after 14-15 weeks of hydrocarbon contamination. The community response of the contaminated soils had changed from that of the control soils after four weeks of bioremediation, and did not return in similarity to the control over the course of the experiment.

39

Thöming, Gunda. "Soil application of neem products in IPM controlling thrips (Thysanoptera: Thripidae) in vegetable crops /". [S.l.] : [s.n.], 2005. http://deposit.ddb.de/cgi-bin/dokserv?idn=979446007.

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40

Davis, Cathryn Joyce. "Cover crops for soil health and forage". Thesis, Kansas State University, 2016. http://hdl.handle.net/2097/34537.

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Master of Science
Department of Agronomy
DeAnn R. Presley
Cover crops have numerous benefits and while cover crops have been used for centuries, currently there are few producers in Kansas growing them and so there is a need for additional research on how cover crops affect soil properties, and on the potential for utilizing cover crops as forage. Two studies are presented in this thesis. The first study evaluated the use of cover crops in a vegetable production system as compared to a fully tilled control. This study evaluated soil physical properties in the form of wet aggregate stability and infiltration, and microbial properties by soil microbial biomass carbon (MBC). Over the three year study, the most pronounced differences observed were in the wet aggregate stability between the cover crop and control treatments where the cover crop treatments had better soil aggregation compared to the control. At the conclusion of the study, there was not a difference between fall and spring planted cover crop treatments. The second study evaluates species composition and forage quality of various combinations of multi-species cover crop mixtures. This study evaluated sixteen treatments, each consisting of a three-way mixture of a brassica (turnip or radish), grass (rye, wheat, barley, oat), and a legume (berseem clover or Austrian winter pea). Species composition analysis found that the brassica species dominated the mixtures (60-80% by mass on a dry weight basis) in 2014 while the grass species were dominant (62 – 67%) in 2015. Overall all treatments produced prime quality forage (as compared to hay values), however some treatments cost significantly more to plant than others. Therefore an economic analysis compared the treatments and found that the treatments containing turnips and oats generally provided the best return on investment given that both of these species were among the cheapest to plant and produced moderate to high biomass compared to the other treatments. The results of these projects point to the potential benefits that cover crops can have for producers interested in improving soil or utilizing cover crops for forage.

41

Austin, Peter Dalton. "An Evaluation Of Vermicompost As A Fast-Acting Nitrogen Amendment To Mitigate Nitrogen Deficiencies In Organic Vegetable Production". ScholarWorks @ UVM, 2015. http://scholarworks.uvm.edu/graddis/505.

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For sustained production, organic agriculture depends on plant needs being synchronized with the release of nutrients from organic amendments during decomposition within the soil. Because decomposition is strongly dependent on soil moisture and temperature, nutrient needs may not always be met as planned or synchronous with plant need. Unlike conventional agriculture, fast acting amendments are not readily available. Much of the evidence that vermicompost benefits crop production comes from studies on seed germination and production of starts in greenhouses. Yet, there is a dearth of information derived from field studies. Soil, soil and water nitrogen, plant development, and marketable yield were investigated by implementing field plot trials with both starts grown in greenhouses (Experiment 1) and directly seeded (Experiment 2) crops to test hypotheses on fertility, economics and environmental impacts. Results from Experiment 1 showed that plant production was dramatically increased both in the greenhouse as well as subsequently in the field for vermicompost treatments and directly correlates to economic differences. Results from Experiment 2 show that plant production differences between compost treatments vary by site. There was no significant difference in soil and soil water NO3-N, NH4-N and Total Inorganic Nitrogen (TIN) among treatments, site or experiment. The timely rate of plant development in greenhouse started VC treatments shows great potential to be the first to market with fresh produce when other treatments are still waiting to transplant.

42

Korre, Anna. "A methodology for the statistical and spatial analysis of soil contamination in GIS". Thesis, Imperial College London, 1997. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.266111.

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43

Metwaly, Hassan Ali Hassan. "A study of groundwater contamination and bioremediation treatment using natural soil and vegetation". Thesis, University of Glasgow, 1999. http://theses.gla.ac.uk/2851/.

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This thesis is concerned with the following studies : 1- Ammonium analysis in soil and water including the determination of low levels of ammonium (<0.1 mg N/1) in groundwater and the colorimetric analysis of highly coloured groundwater samples. 2- An investigation of groundwater quality and soils at a contaminated industrial site. 3- Bioremediation treatment of the ammonium and nitrate contaminated groundwater using natural soil and vegetation and using soil incubation and pot experiments. These findings of a pot experiment suggest the possibility of applying the bioremediation treatment of the ammonium and nitrate contaminated water in the field. A field study should be undertaken to evaluate the efficiency of this bioremediation treatment. This field study would require a suitable uniform area to lay out the plots, preferably close to the source of water to be used. In addition, it is necessary to carry out a hydrological survey to determine the following aspects: 1-The size of groundwater reservoir. 2-The rate of removal of the water. 3-The time scale of the water application. The climatic conditions such as rainfall, potential evapotranspiration and temperature should be taken into consideration when carrying out the bioremediation treatment in the field as these climatic conditions affect the water requirements and the growth of grass. There are three options to apply the contaminated groundwater as follows : 1-To apply the contaminated groundwater at low or high volume depending on its level of nitrogen. 2-To blend well water with high level of nitrogen with well water with low level of nitrogen to achieve a realistic irrigation rate at a suitable nitrogen level. 3-To overirrigate in expectation that ammonium would be retained in the soil. The ryegrass used in this bioremediation treatment can be disposed of by incineration and landfilling the ash or landfilling the grass.

44

Sun, Chin-Cheng 1960. "A stochastic approach for characterizing soil and groundwater contamination at heterogeneous field sites". Thesis, Massachusetts Institute of Technology, 1998. http://hdl.handle.net/1721.1/46140.

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45

McGinley, Susan. "Remediating Soil and Groundwater Contamination: Tools and Strategies that are Making a Difference". College of Agriculture and Life Sciences, University of Arizona (Tucson, AZ), 2004. http://hdl.handle.net/10150/622207.

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46

Birnstingl, Jeremy G. A. "An investigation into bioremediation techniques applied to polycyclic aromatic hydrocarbons in a manufactured gas plant soil". Thesis, Lancaster University, 1996. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.364323.

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47

Testen, Anna Louise. "Participatory Research to Improve Soil and Plant Health on Vegetable Farms in Tanzania and Ohio". The Ohio State University, 2017. http://rave.ohiolink.edu/etdc/view?acc_num=osu1491990803745543.

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48

Dehzoei, Ali Mostafavi. "Analytical methods and instrumentation for the determination of organophosphorus pesticides in fruit and vegetable substrates". Thesis, University of Salford, 1991. http://usir.salford.ac.uk/14745/.

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The chromatographic behaviour of four organophosphorus pesticides has been investigated, using capillary gas liquid chromatography-mass spectrometry (GC-MS), and packed and wide bore capillary gas liquid chromatography with electron capture detection (GC-ECD). The first part of this thesis (Chapter 3) embodies the application of high performance capillary gas liquid chromatography-mass spectrometry and the development of the methodology for analysis of pesticides in fruit and vegetable substrates. Manipulation of GC-MS data during the sample analysis is necessary in order to eliminate the problems arising from the complexity of the samples. The application of selected ion monitoring (SIM) in GC-MS is to a large extent limited by selection of the ion for monitoring, selection of internal standard, optimisation of electrometer zero, the electron multiplier voltage, the selected mass interval, column selection for GC-MS analysis and tuning of the quadrupole GC-MS. A major concern was with the determination of the optimum conditions for the analysis of substrates containing organophosphorus pesticides by GC-MS following solvent extraction (without clean up steps). The analysis of organophosphorus samples using GC-MS-SIM provides detection limits lower than Pg pesticide injected and very good recovery data. The second part (Chapter 4) deals with the application of GC-ECD. Here the role of packed column support, packed and wide bore capillary column temperature and detector temperature was investigated. Comparisons of the relative responses of the pesticides analysed (i) on packed columns and (ii) on wide bore capillary column under different column and detector cell temperatures were undertaken and the optimal condition for each of the organophosphorus pesticides was determined, under the optimal conditions the detection limits and recovery for fruit and vegetable samples were examined. The results from this method were correlated with the data obtained by GC-MS and found to be in very good agreement. The data obtained from analysis using GC-ECD was found to have a higher precision than that obtained by GC-MS, however GC-MS exhibited a higher selectivity for the determination of these pesticides.

49

Pincus, Lauren Michelle. "Increasing Indigenous Vegetable Yield and Nutritional Quality through Traditionally- and Scientifically-Informed Soil Fertility Management". Thesis, University of California, Davis, 2015. http://pqdtopen.proquest.com/#viewpdf?dispub=3723701.

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Smallholder farms in central Uganda do not reach their agronomic potential in large part due to declining soil fertility. Continuous cultivation and soils that are susceptible to degradation lead to yield declines that threaten household food security. Improvements in soil management are needed to produce both the quantity and quality of food required to reduce food insecurity. However, this requires active farmer participation in the identification and evaluation of different soil management strategies. On-farm and participatory approaches to research were used to evaluate the potential benefits of using Integrated Soil Fertility Management (ISFM) to improve the quantity and nutritional quality of an indigenous vegetable crop, Solanum aethiopicum or nakati, in Uganda's Lake Victoria Crescent. There is increasing recognition of the complementary roles organic and mineral fertilizers play in both short- and long-term soil management. ISFM emphasizes strategically targeted mineral fertilizer use combined with organic inputs to ensure fertilizer use efficiency and crop productivity given the limited availability of all nutrient resources in smallholder systems. Greater yield benefits can be achieved with the combined application of organic and mineral fertilizers compared to either resource applied alone. The ISFM framework also recognizes the influence of social factors on organic and mineral input management. A greater understanding of farmers' soil management decision-making process can guide the development of robust solutions to declining soil fertility.

Yield responses of nakati to organic (composted cow manure) and mineral fertilizers (urea), applied separately and in combination, were measured on farmer-managed plots to evaluate the efficacy of using IFSM on indigenous vegetables. Yield benefits from combined fertility sources were only observed under high fertility application rates with little difference between single or combined sources observed at low fertility rates. Low soil pH led to a significant decline in yields. Yields significantly increased when farmers actively participated in the trials, demonstrating the importance of overall good agronomic practices in achieving yield responses to fertilizer applications.

Measuring the effect of edaphic factors and fertility management strategies on the nutritional value of nakati indicated that uptake of nitrogen and micronutrients were affected primarily by soil pH and fertilizer nitrogen source. Foliar iron and zinc concentrations decreased significantly as soil pH increased, but other soil properties did not affect foliar nutrient concentrations. Foliar nitrogen increased significantly with the use of mineral fertilizer. The practical implications of this are most likely overshadowed when mineral fertilizer applications lead to increasing biomass and foliar nitrogen concentrations are diluted. Smallholder farmers can best attain nutritional benefits from nakati by increasing yields rather than modifying soil environments or fertilizer practices.

A participatory approach was used to document the knowledge and perceptions of farmers regarding their soils and soil management practices. Farmers participated in an ISFM demonstration program where they were exposed to Western scientific soil concepts. Pre-program focus group discussions were used to analyze farmers' existing soil knowledge and perceptions followed by participant observation, post-program interviews and focus group discussions to evaluate if and how scientific soil concepts were assimilated into farmers' soil knowledge. Farmers shared many 'structural similarities' with scientists in how they perceive soil, yet these similarities were often not recognized and utilized when scientists talked to farmers about soil. Thus potentially beneficial technologies, such as the use of mineral fertilizer as part of an ISFM framework, could be at odds with farmers' existing perceptions of fertilizer and remain an underutilized tool in soil fertility management.

50

Merkley, Brett J. "Sources and Pathways of Lead Contamination in Urban Community Gardens in Toledo, Ohio". Bowling Green State University / OhioLINK, 2019. http://rave.ohiolink.edu/etdc/view?acc_num=bgsu1555621213052896.

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Tesi sul tema "Soil and vegetable contamination"

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