Author: Deborah E. Morrison-IbrahimPublisher:
ISBN:
Category : Lead in the body
Languages : en
Pages : 68
Book Description
Lead Distribution in Urban Soils
Author: Deborah E. Morrison-IbrahimPublisher:
ISBN:
Category : Lead in the body
Languages : en
Pages : 68
Book Description
Using Geostatistics to Predict Soil Lead Distribution in Akron and Implications for Urban Gardens
Author: Ortis YankeyPublisher:
ISBN:
Category : Crops and soils
Languages : en
Pages : 68
Book Description
Urban soils are often polluted with lead (Pb) from historical deposition from air pollution and other industrial sources. Lead in soil may pose a significant health risk to children under the age of six years. As community gardens become more common in urban areas in the United States, exposure of children to soil Pb is increased through direct contact with soil and the consumption of plants that are cultivated in urban gardens. The aim of this project was therefore to assess the spatial distribution of soil Pb in the city of Akron (Ohio), and to assess the potential for plants cultivated in urban gardens to absorb soil Pb. This study used four interpolation methods to interpolate soil Pb values at unmeasured locations and a comparison was made between the four methods to assess how best predictions were made for unmeasured locations. The four interpolation techniques used were Ordinary Kriging, Co-kriging, Empirical Bayesian Kriging (EBK) and Inverse Distance Weighting. A survey of urban gardens was also conducted to ascertain the type of plants gardeners most frequently cultivated and whether they adopted measures in reducing plant soil Pb uptake. Results from the study showed that the output surface from the four methods were relatively similar, and most surfaces within the city had soil Pb exceeding 600ppm. The EBK model gave the best predicted surface when the four methods were compared. The study also found that whilst soil Pb was high for most places within the city, gardeners replaced old soils with new clean soil and the majority of the crops they cultivated were fruit vegetables. Therefore the potential for plants cultivated in these gardens to absorb soil Pb is minimal.
Urban Soil Lead Abatement Demonstration Project
Author: The Spatial Distribution of Lead in Urban Residential Soil and Correlations with Urban Land Cover of Balitmore, Maryland
Author: Kirsten SchwarzPublisher:
ISBN:
Category : Lead
Languages : en
Pages : 138
Book Description
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.
Speciation, Distribution, Prediction, and Mobility of Lead in Urban Soils
Author: Jennifer A. BowerPublisher:
ISBN:
Category :
Languages : en
Pages : 236
Book Description
Lead (Pb), a trace metal notorious for its impacts on human health, has achieved worldwide environmental dispersal resulting from centuries of use by human society. The toxicity of Pb is governed largely by its mineral form, which is in turn controlled by pH, localized reactivity and soil processes that differ according to soil type, location and Pb source. Given the context of these localized dependencies, or site specificity, efforts to predict Pb toxicity and refine sustainable remediation techniques are most useful when Pb behavior is constrained and predicted within environments with homogeneous conditions, such as a single soil. I evaluated and predicted the behavior of Pb, a typical anthropogenic contaminant, within a single soil using bioaccessibility testing and predictive geospatial modeling to assess potential impacts and refine sustainable remediation methods. To test the hypothesis that Pb speciation is influenced by competitive sorption processes in soils, I investigated changes in mobility and speciation of Pb upon addition of amendments at multiple scales using flow-through column experiments, soil characterization and synchrotron-based x-ray techniques. Kriging and cokriging maps provided a successful estimation of background and total Pb, the latter incorporating housing age as a secondary variable to increase model accuracy, though efforts to automate detection of background Pb were complicated by approximation of building extents, and overall heterogeneity of soil Pb concentration gives high error. Acute Pb heterogeneity is observed at the scale of a single site among near-structure samples. At the city-scale, determination of bioaccessibility revealed that bioaccessible and total Pb are well-correlated, to the extent that bioaccessibility may be predicted for the soil underlying Burlington, VT; this information, combined with predictive blood lead level modeling and the CDC’s recent establishment of 5 μg kg-1 as a threshold for blood lead toxicity, enabled the establishment of a site-specific revised soil Pb limit of 360 mg kg-1, lower than the EPA’s general soil Pb threshold of 400 mg kg-1. Characterization of leached and unleached soil using scanning electron microscope energy dispersive spectroscopy (SEM-EDS) and microfocused x-ray techniques provided a first look at Pb paint species using synchrotron technologies. Pb was present within paint chips as hydrocerussite, but appeared to weather to anglesite over time. Pb also seemed to act as cation bridge, attracting clay minerals electrostatically and becoming incorporated into heterogeneous soil aggregates. Accessory paint elements are identified in soil and within paint chips and may further complicate these systems. Column experiments, at acidic pH, yielded little evidence of Pb mobility change in response to modification of competitive sorbents. Kinetics of Pb release were driven by pH, with Pb solubilizing at pH of ~4.9 as column soil acidifies. This work provides evidence for changes in Pb speciation over time in urban soils impacted by Pb paint, and presents a framework for predictive risk analysis at a local site using experimental and modeling tools. Multiscale observations and analytical results can be used in future efforts to model and refine sustainable remediation solutions within a site-specific context.
Lead: Its Effects on Environment and Health
Author: Astrid SigelPublisher: Walter de Gruyter GmbH & Co KG
ISBN: 3110434334
Category : Science
Languages : en
Pages : 596
Book Description
Volume 17, entitled Lead: Its Effects on Environment and Health of the series Metal Ions in Life Sciences centers on the interrelations between biosystems and lead. The book provides an up-to-date review of the bioinorganic chemistry of this metal and its ions; it covers the biogeochemistry of lead, its use (not only as gasoline additive) and anthropogenic release into the environment, its cycling and speciation in the atmosphere, in waters, soils, and sediments, and also in mammalian organs. The analytical tools to determine and to quantify this toxic element in blood, saliva, urine, hair, etc. are described. The properties of lead(II) complexes formed with amino acids, peptides, proteins (including metallothioneins), nucleobases, nucleotides, nucleic acids, and other ligands of biological relevance are summarized for the solid state and for aqueous solutions as well. All this is important for obtaining a coherent picture on the properties of lead, its effects on plants and toxic actions on mammalian organs. This and more is treated in an authoritative and timely manner in the 16 stimulating chapters of Volume 17, which are written by 36 internationally recognized experts from 13 nations. The impact of this recently again vibrant research area is manifested in nearly 2000 references, over 50 tables and more than 100 illustrations (half in color). Lead: Its Effects on Environment and Health is an essential resource for scientists working in the wide range from material sciences, inorganic biochemistry all the way through to medicine including the clinic ... not forgetting that it also provides excellent information for teaching.
SPATIAL PREDICTION OF BIOAVAILABILITY AND RISK OF LEAD IN URBAN SOILS TO CHILDREN
Author: Lauren R. StewartPublisher:
ISBN:
Category : Bioavailability
Languages : en
Pages : 61
Book Description
Lead poisoning in young children is a concern in many urban areas, even 30 years after the banning of Pb-based paint and leaded gasoline. Soil and dust have been found to be prominent lead exposure pathways for children because young children often inadvertently ingest contaminated soil and dust through exploratory hand-to-mouth activities. In 2010, 16.6% of 6,550 children tested in Toledo, OH had blood lead levels (BLLs) above the CDC lead poisoning reference level of 5 μg/dL. The objectives of this study were 1) to quantify the concentration and distribution of total and bioavailable lead in soils of Toledo, OH; 2) to relate total lead and bioavailable lead in soils to BLLs in children; and 3) to model the relationship between BLLs in children and spatial variables such as housing age and road density. Outreach education served as a means to educate students about the dangers of soil lead as well as the importance of sampling protocols in science. Students in Toledo area schools were instructed on proper USEPA soil sampling guidelines and were asked to collect soil samples from their yards. A subsample of 81 soils was analyzed for total lead and bioavailable lead. Site-specific total lead and bioavailability data were used in the USEPA Integrated Exposure Uptake and Biokinetic (IEUBK) model to predict BLLs for children under 7 years of age. A spatial index model was derived using fuzzy sets, analytical hierarchy process (AHP) and weighted linear combination (WLC) to relate 6 spatial predictor variables to the predicted BLLs. It was found that 8.6% of sampled sites had total lead concentrations above the USEPA action level of 400 mg/kg, but 28.4% of soils samples yielded predicted elevated BLLs, suggesting the action level is set too high. The majority of soil samples had lead bioavailability values above 60%, thus increasing the risk of lead poisoning. The spatial variables influencing risk of lead poisoning from most important to least important were age of housing, road density, percent impervious surfaces, home value, household income and soil type. The data predict that lead poisoning disproportionately affects children from low socioeconomic status families.
Lead Contamination of Urban Soils and Vegetation by Emissions for Secondary Lead Industries
Author: Estimation of Available Phosphorus in Soils by Extraction with Sodium Bicarbonate
Author: Sterling Robertson OlsenPublisher:
ISBN:
Category : Soils
Languages : en
Pages : 20
Book Description
Urban Soils
Author: Phillip J. CraulPublisher: John Wiley & Sons
ISBN: 9780471189039
Category : Science
Languages : en
Pages : 384
Book Description
The soil which is found in large cities offer distinctive challenges to the landscape architect or horticulturist responsible for maintaining these urban plantings. Often compacted, contaminated, or otherwise unsuitable for use in major landscape projects, these soils require practical methods which can insure a successful outcome of a landscape project. This applications-oriented, introductory reference addresses numerous topics in the field of urban soil science.