Kirk G Scheckel | United States Environmental Protection Agency (original) (raw)
Papers by Kirk G Scheckel
Journal of Toxicology and Environmental Health, Jan 16, 2018
Interest in improved understanding of relationships among soil properties and arsenic (As) bioacc... more Interest in improved understanding of relationships among soil properties and arsenic (As) bioaccessibility has motivated the use of regression models for As bioaccessibility prediction. However, limits in the numbers and types of soils included in previous studies restrict the usefulness of these models beyond the range of soil conditions evaluated, as evidenced by reduced predictive performance when applied to new data. In response, hierarchical models that consider variability in relationships among soil properties and As bioaccessibility across geographic locations and contaminant sources were developed to predict As bioaccessibility in 139 soils on both a mass fraction (mg/kg) and percent basis. The hierarchical approach improved the estimation of As bioaccessibility in study soils. Additionally, the number of soil elements identified as statistically significant explanatory variables increased when compared to previous studies. Specifically, total soil Fe, P, Ca, Co and V were significant explanatory variables in both models, while total As, Cd, Cu, Ni and Zn were also significant in the mass fraction model and Mg was significant in the percent model. The hierarchical approach developed in this study provides a novel tool to explore relationships between soil properties and As bioaccessibility across a broad range of soil types and As contaminant sources encountered in the environment and identifies areas of future mechanistic research to better understand the complexity of interactions between soil properties and As bioaccessibility.
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Journal of Environmental Quality, 2013
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Applied Geochemistry, 2020
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Journal of Environmental Quality, 2012
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Journal of Hazardous Materials, 2021
In this study, a novel method for lead (Pb) immobilization was developed in contaminated soils us... more In this study, a novel method for lead (Pb) immobilization was developed in contaminated soils using iron (III) (Fe3+) in conjunction with 0.05 M H2SO4. During method optimization, a range of microwave treatment times, solid to solution ratios, and Fe2(SO4)3/H2SO4 concentrations were assessed using a mining/smelting impacted soil (BHK2, Pb: 3031 mg/kg), followed by treatment of additional Pb contaminated soils (PP, Pb: 1506 mg/kg, G10, Pb: 2454 mg/kg and SoFC-1, Pb: 6340 mg/kg) using the optimized method. Pb bioaccessibility was assessed using USEPA Method 1340, with Pb speciation determined by X-ray Absorption (XAS) spectroscopy. Treatment efficacy was also validated using an in vivo mouse assay, where Pb accumulation in femur, kidney and liver was assessed to confirm in vitro bioaccessibility outcomes. Results showed that Pb bioaccessibility could be reduced by 77.4-97.0% following treatment of soil with Fe2(SO4)3 (0.4-1.0 M), H2SO4 (0.05 M) at 150 °C for 60 min in a closed microwave system. Results of bioavailability assessment demonstrated treatment effect ratio of 0.06-0.07 in femur, 0.06-0.27 in kidney and 0.06-0.11 in liver (bioavailability reduction between 73% and 93%). Formation of plumbojarosite in treated soils was confirmed by XAS analysis.
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Critical Reviews in Environmental Science and Technology, 2017
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... sound. A vast amount of knowledge clearly illustrates the decisive role of metal speciation w... more ... sound. A vast amount of knowledge clearly illustrates the decisive role of metal speciation when metal bioavailability and phytoavailability in the environment have to be assessed ( [McNear et al., 2007] and [Ryan et al., 2004] ). ...
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Environmental Health Perspectives, 2021
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Proceedings of the National Academy of Sciences, 2020
Exposure to lead (Pb) during early life has persistent adverse health effects. During childhood, ... more Exposure to lead (Pb) during early life has persistent adverse health effects. During childhood, ingestion of bioavailable Pb in contaminated soils can be a major route of Pb absorption. Remediation to alter physiochemical properties of soil-borne Pb can reduce Pb bioavailability. Our laboratory-based approach for soil Pb remediation uses addition of iron (Fe) sulfate and application of heat to promote formation of plumbojarosite (PLJ), a sparingly soluble Pb-Fe hydroxysulfate mineral. We treated two soils with anthropogenic Pb contamination and samples of clean topsoil spiked with various Pb compounds (i.e., carbonate, chloride, phosphate [P], or sulfate) to convert native Pb species to PLJ and used a mouse assay to assess relative bioavailability (RBA) of Pb in untreated (U) and remediated soils. Bone and blood Pb levels were significantly lower (P < 0.001, Student's t test) in mice that consumed diets amended with remediated soils than with U soils. Estimated RBA for Pb in...
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New Scientist, 2013
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Environmental Science & Technology, 2019
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Soil Systems, 2018
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Environment International, 2019
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Soil Systems, 2018
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Environmental science & technology, Jan 25, 2018
Effects of different soil amendment treatments on the bioavailability of lead (Pb) in soil from a... more Effects of different soil amendment treatments on the bioavailability of lead (Pb) in soil from a smelter emission contaminated site in Joplin, Missouri, were evaluated in a mouse model. Similar estimates of relative bioavailability for Pb in untreated or treated soil were obtained in mice and in the well-established juvenile swine model. In the mouse model, chemical and physical remediation strategies using phosphate (phosphoric acid or triple superphosphate) combined with iron oxide or biosolids compost significantly reduced soil Pb bioavailability. Notably, effects of these remediation procedures were persistent, given that up to 16 years had elapsed between soil treatments and sample collection. Remediation of soils was associated with changes in Pb species present in soil. Differences in Pb species in ingested soil and in feces from treated mice indicated that changes in Pb speciation occurred during transit through the gastrointestinal tract. Use of the mouse model facilitates...
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Environmental health perspectives, Aug 1, 2018
The diet is emerging as the dominant source of arsenic exposure for most of the U.S. population. ... more The diet is emerging as the dominant source of arsenic exposure for most of the U.S. population. Despite this, limited regulatory efforts have been aimed at mitigating exposure, and the role of diet in arsenic exposure and disease processes remains understudied. In this brief, we discuss the evidence linking dietary arsenic intake to human disease and discuss challenges associated with exposure characterization and efforts to quantify risks. In light of these challenges, and in recognition of the potential longer-term process of establishing regulation, we introduce a framework for shorter-term interventions that employs a field-to-plate food supply chain model to identify monitoring, intervention, and communication opportunities as part of a multisector, multiagency, science-informed, public health systems approach to mitigation of dietary arsenic exposure. Such an approach is dependent on coordination across commodity producers, the food industry, nongovernmental organizations, he...
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Journal of Toxicology and Environmental Health, Jan 16, 2018
Interest in improved understanding of relationships among soil properties and arsenic (As) bioacc... more Interest in improved understanding of relationships among soil properties and arsenic (As) bioaccessibility has motivated the use of regression models for As bioaccessibility prediction. However, limits in the numbers and types of soils included in previous studies restrict the usefulness of these models beyond the range of soil conditions evaluated, as evidenced by reduced predictive performance when applied to new data. In response, hierarchical models that consider variability in relationships among soil properties and As bioaccessibility across geographic locations and contaminant sources were developed to predict As bioaccessibility in 139 soils on both a mass fraction (mg/kg) and percent basis. The hierarchical approach improved the estimation of As bioaccessibility in study soils. Additionally, the number of soil elements identified as statistically significant explanatory variables increased when compared to previous studies. Specifically, total soil Fe, P, Ca, Co and V were significant explanatory variables in both models, while total As, Cd, Cu, Ni and Zn were also significant in the mass fraction model and Mg was significant in the percent model. The hierarchical approach developed in this study provides a novel tool to explore relationships between soil properties and As bioaccessibility across a broad range of soil types and As contaminant sources encountered in the environment and identifies areas of future mechanistic research to better understand the complexity of interactions between soil properties and As bioaccessibility.
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Journal of Environmental Quality, 2013
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Applied Geochemistry, 2020
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Journal of Environmental Quality, 2012
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Journal of Hazardous Materials, 2021
In this study, a novel method for lead (Pb) immobilization was developed in contaminated soils us... more In this study, a novel method for lead (Pb) immobilization was developed in contaminated soils using iron (III) (Fe3+) in conjunction with 0.05 M H2SO4. During method optimization, a range of microwave treatment times, solid to solution ratios, and Fe2(SO4)3/H2SO4 concentrations were assessed using a mining/smelting impacted soil (BHK2, Pb: 3031 mg/kg), followed by treatment of additional Pb contaminated soils (PP, Pb: 1506 mg/kg, G10, Pb: 2454 mg/kg and SoFC-1, Pb: 6340 mg/kg) using the optimized method. Pb bioaccessibility was assessed using USEPA Method 1340, with Pb speciation determined by X-ray Absorption (XAS) spectroscopy. Treatment efficacy was also validated using an in vivo mouse assay, where Pb accumulation in femur, kidney and liver was assessed to confirm in vitro bioaccessibility outcomes. Results showed that Pb bioaccessibility could be reduced by 77.4-97.0% following treatment of soil with Fe2(SO4)3 (0.4-1.0 M), H2SO4 (0.05 M) at 150 °C for 60 min in a closed microwave system. Results of bioavailability assessment demonstrated treatment effect ratio of 0.06-0.07 in femur, 0.06-0.27 in kidney and 0.06-0.11 in liver (bioavailability reduction between 73% and 93%). Formation of plumbojarosite in treated soils was confirmed by XAS analysis.
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Critical Reviews in Environmental Science and Technology, 2017
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... sound. A vast amount of knowledge clearly illustrates the decisive role of metal speciation w... more ... sound. A vast amount of knowledge clearly illustrates the decisive role of metal speciation when metal bioavailability and phytoavailability in the environment have to be assessed ( [McNear et al., 2007] and [Ryan et al., 2004] ). ...
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Environmental Health Perspectives, 2021
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Proceedings of the National Academy of Sciences, 2020
Exposure to lead (Pb) during early life has persistent adverse health effects. During childhood, ... more Exposure to lead (Pb) during early life has persistent adverse health effects. During childhood, ingestion of bioavailable Pb in contaminated soils can be a major route of Pb absorption. Remediation to alter physiochemical properties of soil-borne Pb can reduce Pb bioavailability. Our laboratory-based approach for soil Pb remediation uses addition of iron (Fe) sulfate and application of heat to promote formation of plumbojarosite (PLJ), a sparingly soluble Pb-Fe hydroxysulfate mineral. We treated two soils with anthropogenic Pb contamination and samples of clean topsoil spiked with various Pb compounds (i.e., carbonate, chloride, phosphate [P], or sulfate) to convert native Pb species to PLJ and used a mouse assay to assess relative bioavailability (RBA) of Pb in untreated (U) and remediated soils. Bone and blood Pb levels were significantly lower (P < 0.001, Student's t test) in mice that consumed diets amended with remediated soils than with U soils. Estimated RBA for Pb in...
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New Scientist, 2013
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Environmental Science & Technology, 2019
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Soil Systems, 2018
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Environment International, 2019
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Soil Systems, 2018
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Environmental science & technology, Jan 25, 2018
Effects of different soil amendment treatments on the bioavailability of lead (Pb) in soil from a... more Effects of different soil amendment treatments on the bioavailability of lead (Pb) in soil from a smelter emission contaminated site in Joplin, Missouri, were evaluated in a mouse model. Similar estimates of relative bioavailability for Pb in untreated or treated soil were obtained in mice and in the well-established juvenile swine model. In the mouse model, chemical and physical remediation strategies using phosphate (phosphoric acid or triple superphosphate) combined with iron oxide or biosolids compost significantly reduced soil Pb bioavailability. Notably, effects of these remediation procedures were persistent, given that up to 16 years had elapsed between soil treatments and sample collection. Remediation of soils was associated with changes in Pb species present in soil. Differences in Pb species in ingested soil and in feces from treated mice indicated that changes in Pb speciation occurred during transit through the gastrointestinal tract. Use of the mouse model facilitates...
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Environmental health perspectives, Aug 1, 2018
The diet is emerging as the dominant source of arsenic exposure for most of the U.S. population. ... more The diet is emerging as the dominant source of arsenic exposure for most of the U.S. population. Despite this, limited regulatory efforts have been aimed at mitigating exposure, and the role of diet in arsenic exposure and disease processes remains understudied. In this brief, we discuss the evidence linking dietary arsenic intake to human disease and discuss challenges associated with exposure characterization and efforts to quantify risks. In light of these challenges, and in recognition of the potential longer-term process of establishing regulation, we introduce a framework for shorter-term interventions that employs a field-to-plate food supply chain model to identify monitoring, intervention, and communication opportunities as part of a multisector, multiagency, science-informed, public health systems approach to mitigation of dietary arsenic exposure. Such an approach is dependent on coordination across commodity producers, the food industry, nongovernmental organizations, he...
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