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Author: Manfred M. Mayer Publisher: ISBN: Category : Lead Languages : en Pages : 0
Book Description
Measuring the reduction of in vitro bioaccessible (IVBA) Pb from the addition of phosphate amendments has been researched for more than two decades. The mean change in IVBA Pb as a fraction of total Pb (AC) and relative to the IVBA Pb of the control soil (RC) was determined with a random effects meta-analysis. The addition of P to contaminated soils consistently reduced IVBA Pb. The mean AC was approximately -12% and mean RC was approximately -25% based on 76 soils that measured IVBA Pb with a method other than EPA Method 1340. This analysis determined that soluble amendments reduce bioaccessible Pb more than insoluble amendments, phosphoric acid is more effective than other phosphate amendments, and urban Pb contamination, associated with legacy Pb-paint and tetraethyl Pb, showed lower reductions than other Pb sources. Meta-regression identified high IVBA Pb in the control, low incubated soil pH, and high total Pb with the greater reductions in AC and RC. In order to facilitate comparisons across future remediation research, a set of minimum reported data should be included in published studies and researchers should use standardized in vitro bioaccessibility methods developed for P-treated soils. Meta-analysis identified lowered incubated soil pH as correlated with greater reductions in IVBA Pb but previous studies have found purposeful acidification to have no significant effect on IVBA Pb. In this study, three soils (IDs: AG, TH, SA), previously incubated with triple superphosphate, were acidified to pH 3 with 6M trace-metal grade HCl, and subsequently neutralized with 6M NaOH, to determine if acidification of soil influences IVBA Pb in soils amended with phosphate. The acidification of soil took varying amounts of HCl and markedly less 6M NaOH to return soils to initial pH. The treatment effect ratios (TER) for acidification and neutralization varied by soil. No significant differences were observed for any treatment in SA soil. The acidified treatments had significantly lower bioaccessible Pb for the other two soils with a TER of 0.52 for TH soil and 0.70 for AG soil. Only TH soil had a neutralized treatment which was significantly lower than the control (TER of 0.76). Importantly, no increase in bioaccessible Pb was observed in any soil implying no increased risk from soil acidification. Further primary research is needed to determine the relationship between different soil properties and reduction in bioaccessible Pb attributable to the addition of P amendments.
Author: Manfred M. Mayer Publisher: ISBN: Category : Lead Languages : en Pages : 0
Book Description
Measuring the reduction of in vitro bioaccessible (IVBA) Pb from the addition of phosphate amendments has been researched for more than two decades. The mean change in IVBA Pb as a fraction of total Pb (AC) and relative to the IVBA Pb of the control soil (RC) was determined with a random effects meta-analysis. The addition of P to contaminated soils consistently reduced IVBA Pb. The mean AC was approximately -12% and mean RC was approximately -25% based on 76 soils that measured IVBA Pb with a method other than EPA Method 1340. This analysis determined that soluble amendments reduce bioaccessible Pb more than insoluble amendments, phosphoric acid is more effective than other phosphate amendments, and urban Pb contamination, associated with legacy Pb-paint and tetraethyl Pb, showed lower reductions than other Pb sources. Meta-regression identified high IVBA Pb in the control, low incubated soil pH, and high total Pb with the greater reductions in AC and RC. In order to facilitate comparisons across future remediation research, a set of minimum reported data should be included in published studies and researchers should use standardized in vitro bioaccessibility methods developed for P-treated soils. Meta-analysis identified lowered incubated soil pH as correlated with greater reductions in IVBA Pb but previous studies have found purposeful acidification to have no significant effect on IVBA Pb. In this study, three soils (IDs: AG, TH, SA), previously incubated with triple superphosphate, were acidified to pH 3 with 6M trace-metal grade HCl, and subsequently neutralized with 6M NaOH, to determine if acidification of soil influences IVBA Pb in soils amended with phosphate. The acidification of soil took varying amounts of HCl and markedly less 6M NaOH to return soils to initial pH. The treatment effect ratios (TER) for acidification and neutralization varied by soil. No significant differences were observed for any treatment in SA soil. The acidified treatments had significantly lower bioaccessible Pb for the other two soils with a TER of 0.52 for TH soil and 0.70 for AG soil. Only TH soil had a neutralized treatment which was significantly lower than the control (TER of 0.76). Importantly, no increase in bioaccessible Pb was observed in any soil implying no increased risk from soil acidification. Further primary research is needed to determine the relationship between different soil properties and reduction in bioaccessible Pb attributable to the addition of P amendments.
Author: H. Magdi Selim Publisher: CRC Press ISBN: 148223680X Category : Nature Languages : en Pages : 381
Book Description
Edited by One of the Best Specialists in Soil Science Recent studies reveal that Phosphorus (P) in the form of phosphate, a macronutrient essential for plant growth, and crop yields can influence the bioavailability, retention, and mobility of trace elements, metal(loid)s, and radio nuclides in soils. When this occurs, phosphates can affect the dynamics of heavy metals and influence soil characteristics, impacting soil mobility and toxicity. Phosphate in Soils: Interaction with Micronutrients, Radionuclides and Heavy Metals utilizes the latest research to emphasize the role that phosphate plays in enhancing or reducing the mobility of heavy metals in soil, and the soil-water-plant environment. It provides an in-depth understanding of each heavy metal species, and expands on phosphate interactions in geological material. Composed of 12 chapters, this text: Provides an overview of the reactions of metal(loid)s and common P compounds that are used as fertilizer in soils Emphasizes the effect of phosphorus on copper and zinc adsorption in acid soils Discusses findings on the influence of phosphate compounds on speciation, mobility, and bioavailability of heavy metals in soils as well as the role of phosphates on in situ and phytoremediation of heavy metals for contaminated soils Places emphasis on the influence of phosphate on various heavy metals species in soils, and their solubility/mobility and availability Provides extensive information on testing various high phosphate materials for remediation of heavy metal, micronutrients, and radionuclides contaminated sites Explores the reactivity of heavy metals, micronutrients and radionuclides elements in several soils Presents a case study illustrating various remediation efforts of acidic soils and remediation of Cu, Zn, and lead (Pb) contaminated soils around nonferrous industrial plants Emphasizes the significance of common ions (cations and anions) on phosphate mobility and sorption in soils, and more The author includes analytical and numerical solutions along with hands-on applications, and addresses other topics that include the transport and sorption modeling of heavy metals in the presence of phosphate at different scales in the vadose zone.
Author: Anthony Michael Fulford Publisher: ISBN: Category : Languages : en Pages : 104
Book Description
A sequential phosphorus extraction scheme was applied to a lead-(Pb) contaminated soil in Herculaneum, MO for both a field and incubation study. The objectives of this project were; (1) lower soil P fixation and retention through the addition of organically amended P sources; (2) identify the distribution of P among five operationally defined pools of extractable phosphate following treatment incorporation; (3) determine portion of labile P derived from vermicompost (VC); and (4) identify treatments that could potentially lower bioaccessible Pb over an eight-week period. Sequential fractionation identified the Aluminum-associated P (Al-P) fraction as the fraction responding the most to treatment addition. Retention as Al-P could be effectively reduced using the organic amendments evaluated in this study in combination with VC. Amended triple super phosphate (TSP) and VC lowered bioaccessible Pb concentration compared to a non-amended plot. This finding may provide some experimental justification for the application of VC in combination with TSP to Pb-contaminated soil. Further research focusing on a combination of these P sources applied to Pb-contaminated soil could elucidate the conclusion postulated by this research.
Author: Zachary Robert Tondre Publisher: ISBN: Category : Languages : en Pages : 100
Book Description
This study was an investigation of the bioaccessibility of Pb in the presence of phosphate acting as an immobilizing constituent in the form of fish bone material, specifically Apatite II. Phosphate-induced Pb immobilization refers to the process by which Pb ions replace calcium ions and form insoluble Pb-phosphate. A commercially available A-horizon soil was spiked with dried Pb-bearing paint containing various Pb forms (e.g., carbonates, sulfates, and oxides). The paints were added to the soil at 2% weight for weight (w/w). The paints (in solid form) were initially ground and sieved through a
Author: B. J. Alloway Publisher: Springer Science & Business Media ISBN: 9780751401981 Category : Nature Languages : en Pages : 392
Book Description
Heavy metals in soils continue to receive increasing attention due to the growing scientific and public awareness of environmental issues and the development of analytical techniques to measure their concentrations accurately. Building on the success and acclaim of the first edition, this book continues to provide an up-to-date, balanced and comprehensive review of the subject in two sections: the first providing an introduction to the metals chemistry, sources and methods used for their analysis; and the second containing chapters dealing with individual elements in detail.
Author: National Research Council Publisher: National Academies Press ISBN: 0309086256 Category : Technology & Engineering Languages : en Pages : 433
Book Description
Bioavailability refers to the extent to which humans and ecological receptors are exposed to contaminants in soil or sediment. The concept of bioavailability has recently piqued the interest of the hazardous waste industry as an important consideration in deciding how much waste to clean up. The rationale is that if contaminants in soil and sediment are not bioavailable, then more contaminant mass can be left in place without creating additional risk. A new NRC report notes that the potential for the consideration of bioavailability to influence decision-making is greatest where certain chemical, environmental, and regulatory factors align. The current use of bioavailability in risk assessment and hazardous waste cleanup regulations is demystified, and acceptable tools and models for bioavailability assessment are discussed and ranked according to seven criteria. Finally, the intimate link between bioavailability and bioremediation is explored. The report concludes with suggestions for moving bioavailability forward in the regulatory arena for both soil and sediment cleanup.
Author: John Stephen Weber Publisher: ISBN: Category : Languages : en Pages : 104
Book Description
A diverse suite of research has focused on the immobilization of lead (Pb) compounds in soil through the application of phosphate-based amendments that create insoluble Pb compounds. Water quality threats associated with the phosphorus (P) remediation technology are a concern, particularly near riparian areas. This study investigated P fertilizer application rates on metals and P loss via surface runoff following P application to a lead contaminated alluvial soil. Soil was treated with Triple Super Phosphate (TSP) at differing molar ratios of P to Pb: 0:1 (control); 4:1; 8:1; and 16:1. Effluents from treated soils were collected during rainfall simulation (RFS) events at six months and one year post-treatment and analyzed for total and dissolved P and Pb loss. At elevated P treatment levels (8:1, 16:1 P:Pb), P and total Pb concentrations were significantly greater (p
Author: Publisher: ISBN: Category : Languages : en Pages : 11
Book Description
Recently the Centers for Disease Control and Prevention lowered the blood Pb reference value to 5 [mu]g/dL. The lower reference value combined with increased repurposing of postindustrial lands are heightening concerns and driving interest in reducing soil Pb exposures. As a result, regulatory decision makers may lower residential soil screening levels (SSLs), used in setting Pb cleanup levels, to levels that may be difficult to achieve, especially in urban areas. This study discusses challenges in remediation and bioavailability assessments of Pb in urban soils in the context of lower SSLs and identifies research needs to better address those challenges. Although in situ remediation with phosphate amendments is a viable option, the scope of the problem and conditions in urban settings may necessitate that SSLs be based on bioavailable rather than total Pb concentrations. However, variability in soil composition can influence bioavailability testing and soil amendment effectiveness. Finally, more data are urgently needed to better understand this variability and increase confidence in using these approaches in risk-based decision making, particularly in urban areas.
Author: Manfred M. Mayer
Author: Manfred M. Mayer
Author: H. Magdi Selim
Author: Anthony Michael Fulford
Author: Luke Gatiboni
Author: Zachary Robert Tondre
Author: B. J. Alloway
Author: National Research Council
Author: 
Author: John Stephen Weber
Author: