The Effect of in Situ Spatial Heterogeneity of Lead in Soil on Plant Uptake PDF Download

Author: Grace Oyiza Solomon-Wisdom
Publisher:
ISBN:
Category :
Languages : en
Pages :

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Author: Grace Oyiza Anibasa
Publisher:
ISBN: 9783330008335
Category :
Languages : en
Pages : 388

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Author: Jacqueline Yvette Thomas
Publisher:
ISBN:
Category :
Languages : en
Pages :

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Heterogeneity of contaminants in soils can vary spatially over a range of scales, causing uncertainty in environmental measurements of contaminant concentrations. Sampling designs may aim to reduce the impact of on-site heterogeneity, by using composite sampling, increased sample mass and off-site homogenisation, yet they could overlook the small scale heterogeneity that can have significant implications for plant uptake of contaminants. Moreover, composite sampling and homogenisation may not be relevant to target receptor behaviour, e.g. plants, and studies, using simplistic models of heterogeneity have shown that it can significantly impact plant uptake of contaminants. The alternative approach, to accept and quantify heterogeneity, requires further exploration as contaminant heterogeneity is inevitable within soils and its quantification should enable improved reliability in risk assessment and understanding variability in plant contaminant uptake. This thesis reports the development of a new sampling design, to characterise and quantify contaminant heterogeneity at scales, from 0.02m to 20m, using in situ measurement techniques, and 0.005m to 0.0005m, using ex situ techniques. The design was implemented at two contaminated land sites, with contrasting heterogeneity based upon historic anthropogenic activity and showed heterogeneity varying between contaminants and at different spatial scales, for Pb, Cu and Zn. Secondly, this research demonstrates how contaminant heterogeneity measured in situ can be recreated in a pot experiment, at a scale specific to the plant under study. Results, from 4 different plant species, demonstrated that existing simplistic models of heterogeneity are an inadequate proxy for plant performance and contaminant uptake under field conditions, and significant differences were found in plant contaminant concentrations between simplistic models and those based upon actual site measurements of heterogeneity. Implications of heterogeneity on plant roots were explored in the final experiment showing significant differences in root biomass between patches of differing contaminant concentrations.

Author: Kirsten Schwarz
Publisher:
ISBN:
Category : Lead
Languages : en
Pages : 138

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Lead contamination of the urban environment is not a new phenomenon. A great deal of research has focused on the health effects of lead-based paint. Less attention, however, has been given to the potential problem of soil contaminated with lead from the past use of lead-containing products such as lead-based paint and leaded gasoline. Identifying areas of high contamination is necessary in order to prioritize soil remediation and public health efforts. This requires a comprehensive understanding of a highly heterogeneous and dynamic system. This research addresses whether land use or land cover is a better predictor of lead concentrations in soil. Specifically, this research addresses whether landscape features, including trees, lawns, buildings, and roads, can be used to predict lead concentrations in soil. Through a method of rapid assessment of soil lead concentrations, I gathered spatially explicit data from urban residential yards to generate several models that predict the spatial distribution of lead in soil. Using the results of these models, potential inequities associated with the modeled spatial distribution of lead in soil and socio-demographic features were explored. The results of this study suggest that the distribution of lead in urban residential soils is more closely correlated with features of urban land cover compared to metrics of land use. Specifically, the spatial distribution of lead in urban residential soils is strongly influenced by three factors: housing age, distance to the major road networks, and distance to built structures. Through the comparison of various spatial models, this research demonstrates that a greater amount of variation in the data is explained by machine learning techniques compared to traditional modeling techniques. In addition, important correlations between the modeled distribution of lead in soil and socio-demographic features such as race and poverty have been identified. Specifically, a greater amount of soil contamination is predicted to be present in high poverty areas. This research contributes to the growing field of urban ecology by advancing our knowledge of how spatial heterogeneity affects the distribution of a critical pollutant in urban systems. This work also tests the suitability of using land cover as a predictive ecological variable.

Author: Terrance David Loecke
Publisher:
ISBN:
Category : Growth (Plants)
Languages : en
Pages : 392

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Author: Wilfred D. Stein
Publisher: Elsevier
ISBN: 0124165834
Category : Science
Languages : en
Pages : 423

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An introduction to the principles of membrane transport: How molecules and ions move across the cell membrane by simple diffusion and by making use of specialized membrane components (channels, carriers, and pumps). The text emphasizes the quantitative aspects of such movement and its interpretation in terms of transport kinetics. Molecular studies of channels, carriers, and pumps are described in detail as well as structural principles and the fundamental similarities between the various transporters and their evolutionary interrelationships. The regulation of transporters and their role in health and disease are also considered. - Provides an introduction to the properties of transport proteins: channels, carriers, and pumps - Presents up-to-date information on the structure of transport proteins and on their function and regulation - Includes introductions to transport kinetics and to the cloning of genes that code transport proteins - Furnishes a link between the experimental basis of the subject and theoretical model building

Author: Herman J.P. Eijsackers
Publisher: Springer Science & Business Media
ISBN: 9401120080
Category : Science
Languages : en
Pages : 810

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Increasing awareness of the irreversible and long-lasting impacts of deterioration and pollution of soils and sediments has had an important influence on environmental policies and research in the last decade. The complexity of the soil and sediment systems and its processes cannot be tackled properly unless scientists from different disciplines work together. With this in mind, a number of multidisciplinary soil research programmes have been started in various European countries. They involve different disciplinary approaches and they aim at different fields of application: agriculture, land use and town and country planning, drinking water supply, nature management. The results that are now appearing need to be integrated in a scientifically sound and useful way. The first European Conference on Integrated Research for Soil and Sediment Protection and Remediation was intended to foster this. The volume contains the edited and selected proceedings of this Conference.

Author:
Publisher:
ISBN:
Category : Hydrology
Languages : en
Pages : 962

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Author:
Publisher:
ISBN:
Category : Medicine
Languages : en
Pages : 2388

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Vols. for 1963- include as pt. 2 of the Jan. issue: Medical subject headings.

Author: Jun Ni
Publisher: Frontiers Media SA
ISBN: 2832523811
Category : Science
Languages : en
Pages : 274

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