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Papers by Christian Briggs

Research paper thumbnail of Analysis of Biota to Evaluate the Risks Associated with Chemical Warfare Materiel Present in Sea-Disposed Military Munitions to Human Health and the Environment

Research paper thumbnail of Chemical Warfare Materiel in Sediment at a Deep-Water Discarded Military Munitions Site

Research paper thumbnail of Mercury Release from Soils Amended with Flue Gas Desulfurization Solids

Flue Gas Desulfurization derived gypsum (FGD) can be beneficial when applied as an agricultural s... more Flue Gas Desulfurization derived gypsum (FGD) can be beneficial when applied as an agricultural soil amendment however concern has been raised regarding the release of mercury (Hg) from these materials to the environment. This work investigated Hg release to the air and water associated with soil from Indiana, Alabama, and Ohio amended with FGD in a laboratory setting. FGD was homogenized into each soil at rates of 4.5, 45, and 170t/ha and added at 4.9t/ha as a thin layer to represent a tilled and no-till agricultural setting, respectively. Data was also collected from unamended soils and those with applications of commercial gypsum. 24 hour Hg flux was measured from each material on a seasonal time step over one year. Water that had leached through a representative set of materials was collected seasonally and analyzed for total dissolved and methyl mercury. Perennial rye grass (Lolium perenne) was grown in a subset of soil treatments and Hg accumulation and flux measured.

Research paper thumbnail of Hg release from soils amended with Flue Gas Desulfurization solids

Research paper thumbnail of The Hawaii Undersea Military Munitions Assessment

Deep Sea Research Part II: Topical Studies in Oceanography, 2016

Abstract The Hawaii Undersea Military Munitions Assessment (HUMMA) is the most comprehensive deep... more Abstract The Hawaii Undersea Military Munitions Assessment (HUMMA) is the most comprehensive deep-water investigation undertaken by the United States to look at sea-disposed chemical and conventional munitions. HUMMA׳s primary scientific objective is to bound, characterize and assess a historic deep-water munitions sea-disposal site to determine the potential impact of the ocean environment on sea-disposed munitions and of sea-disposed munitions on the ocean environment and those that use it. Between 2007 and 2012 the HUMMA team conducted four field programs, collecting hundreds of square kilometers of acoustic data for high-resolution seafloor maps, tens of thousands of digital images, hundreds of hours of video of individual munitions, hundreds of physical samples acquired within two meters of munitions casings, and a suite of environmental data to characterize the ocean surrounding munitions in the study area. Using these data we examined six factors in the study area: (1) the spatial extent and distribution of munitions; (2) the integrity of munitions casings; (3) whether munitions constituents could be detected in sediment, seawater or animals near munitions; (4) whether constituent levels at munitions sites differed significantly from levels at reference control sites; (5) whether statistically significant differences in ecological population metrics could be detected between the two types of sites; and (6) whether munitions constituents or their derivatives potentially pose an unacceptable risk to human health. Herein we provide a general overview of HUMMA including overarching goals, methodologies, physical characteristics of the study area, data collected and general results. Detailed results, conclusions and recommendations for future research are discussed in the accompanying papers included in this volume.

Research paper thumbnail of Building upon the Conceptual Model for Soil Mercury Flux: Evidence of a Link Between Moisture Evaporation and Hg Evasion

Water, Air, & Soil Pollution, 2013

Parameters known to influence mercury (Hg) release from soils include substrate and air Hg concen... more Parameters known to influence mercury (Hg) release from soils include substrate and air Hg concentration, light, atmospheric oxidants, temperature, and soil moisture. However, for low Hg-containing soils, the influence of these parameters has been shown to vary across space and time. Here, we expand upon previous work by investigating whether soil–water evaporative loss, which integrates the influence of multiple parameters, could be applied for predicting Hg flux from soil with low Hg concentrations when bare and planted. To investigate our hypothesis, Hg flux was measured from three soil types (<100 ng Hg g−1). When these soils were saturated, flux was suppressed. Soil moisture evaporative stage was used to partition the parameters most important for controlling Hg flux as the soils dried. Classification and regression tree (CART) analyses showed that soil moisture was the most important parameter predicting Hg flux. Results also showed an important predictor for Hg flux was whether actual evaporation (Ea) was equal to potential evaporation (Ep) or Ea < Ep. Depending on evaporative stage, the parameters with the next highest correlation to Hg flux were light, temperature, and soil moisture evaporation rate. The presence of vegetation also influenced flux with lower Hg flux when the plants were transpiring. Results indicate for those developing models that estimate Hg flux from low Hg-containing soils, soil moisture and evaporative stage are useful tools for predicting flux.

Research paper thumbnail of Investigation of the Potential for Mercury Release from Flue Gas Desulfurization Solids Applied as an Agricultural Amendment

Journal of Environment Quality, 2014

The potential for beneficial use of flue gas desulfurization-derived gypsum (FGDG), a coal combus... more The potential for beneficial use of flue gas desulfurization-derived gypsum (FGDG), a coal combustion byproduct, as an agricultural soil amendment is currently being debated. This study investigated the hypothesis that Hg released to air from FGDG will be reduced when amended to planted and bare soils. The potential for enhanced methylmercury (MeHg) production and Hg uptake by plants in soils amended with FGDG was also investigated. Flue gas desulfurization-derived gypsum from three sources was homogenized into three soils at 4.5, 45, and 170 t ha and applied at 4.9 t ha as a thin layer to simulate tilled and no-till applications, respectively. Twenty-four-hour Hg flux was measured from unamended and FGDG-amended soils on a seasonal time step over 1 yr and after disturbing, watering, and planting. Methylmercury in soil, irrigation drainage, and total Hg in plant tissues were quantified. Results should be interpreted within the confines of the experimental setting and materials used for this study. Total Hg concentrations in soils, homogenized with FGDG, were below that considered representative of soil with background values (&amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;lt;100 ng g). Emissions from amended soils were higher initially relative to unamended soils but became similar over time. Significantly less Hg (2%) was lost to the air from FGDG-amended soils (90 g FGDG added for lowest application) than that released from the FGDG alone (30-70%) (50 g FGDG) over 1 yr. Total Hg and MeHg in irrigation drainage and total Hg concentrations measured in plants were similar for amended and unamended soils.

Research paper thumbnail of A Model for the Origin of Rhyolites From South Mountain, Pennsylvania: Implications for Rhyolites Associated With Large Igneous Provinces

…, 2010

High-silica rhyolites, ubiquitous features of continental volcanism, continue to evoke controvers... more High-silica rhyolites, ubiquitous features of continental volcanism, continue to evoke controversy as to their petrogenesis and evolution. We utilized the geochemical characteristics of late Vendian high-silica rhyolites erupted in the Catoctin Volcanic Province at South Mountain in ...

Research paper thumbnail of Distribution of chemical warfare agent, energetics, and metals in sediments at a deep water discarded military munitions site

Deep Sea Research Part II: Topical Studies in Oceanography, 2015

Research paper thumbnail of Analysis of Biota to Evaluate the Risks Associated with Chemical Warfare Materiel Present in Sea-Disposed Military Munitions to Human Health and the Environment

Research paper thumbnail of Chemical Warfare Materiel in Sediment at a Deep-Water Discarded Military Munitions Site

Research paper thumbnail of Mercury Release from Soils Amended with Flue Gas Desulfurization Solids

Flue Gas Desulfurization derived gypsum (FGD) can be beneficial when applied as an agricultural s... more Flue Gas Desulfurization derived gypsum (FGD) can be beneficial when applied as an agricultural soil amendment however concern has been raised regarding the release of mercury (Hg) from these materials to the environment. This work investigated Hg release to the air and water associated with soil from Indiana, Alabama, and Ohio amended with FGD in a laboratory setting. FGD was homogenized into each soil at rates of 4.5, 45, and 170t/ha and added at 4.9t/ha as a thin layer to represent a tilled and no-till agricultural setting, respectively. Data was also collected from unamended soils and those with applications of commercial gypsum. 24 hour Hg flux was measured from each material on a seasonal time step over one year. Water that had leached through a representative set of materials was collected seasonally and analyzed for total dissolved and methyl mercury. Perennial rye grass (Lolium perenne) was grown in a subset of soil treatments and Hg accumulation and flux measured.

Research paper thumbnail of Hg release from soils amended with Flue Gas Desulfurization solids

Research paper thumbnail of The Hawaii Undersea Military Munitions Assessment

Deep Sea Research Part II: Topical Studies in Oceanography, 2016

Abstract The Hawaii Undersea Military Munitions Assessment (HUMMA) is the most comprehensive deep... more Abstract The Hawaii Undersea Military Munitions Assessment (HUMMA) is the most comprehensive deep-water investigation undertaken by the United States to look at sea-disposed chemical and conventional munitions. HUMMA׳s primary scientific objective is to bound, characterize and assess a historic deep-water munitions sea-disposal site to determine the potential impact of the ocean environment on sea-disposed munitions and of sea-disposed munitions on the ocean environment and those that use it. Between 2007 and 2012 the HUMMA team conducted four field programs, collecting hundreds of square kilometers of acoustic data for high-resolution seafloor maps, tens of thousands of digital images, hundreds of hours of video of individual munitions, hundreds of physical samples acquired within two meters of munitions casings, and a suite of environmental data to characterize the ocean surrounding munitions in the study area. Using these data we examined six factors in the study area: (1) the spatial extent and distribution of munitions; (2) the integrity of munitions casings; (3) whether munitions constituents could be detected in sediment, seawater or animals near munitions; (4) whether constituent levels at munitions sites differed significantly from levels at reference control sites; (5) whether statistically significant differences in ecological population metrics could be detected between the two types of sites; and (6) whether munitions constituents or their derivatives potentially pose an unacceptable risk to human health. Herein we provide a general overview of HUMMA including overarching goals, methodologies, physical characteristics of the study area, data collected and general results. Detailed results, conclusions and recommendations for future research are discussed in the accompanying papers included in this volume.

Research paper thumbnail of Building upon the Conceptual Model for Soil Mercury Flux: Evidence of a Link Between Moisture Evaporation and Hg Evasion

Water, Air, & Soil Pollution, 2013

Parameters known to influence mercury (Hg) release from soils include substrate and air Hg concen... more Parameters known to influence mercury (Hg) release from soils include substrate and air Hg concentration, light, atmospheric oxidants, temperature, and soil moisture. However, for low Hg-containing soils, the influence of these parameters has been shown to vary across space and time. Here, we expand upon previous work by investigating whether soil–water evaporative loss, which integrates the influence of multiple parameters, could be applied for predicting Hg flux from soil with low Hg concentrations when bare and planted. To investigate our hypothesis, Hg flux was measured from three soil types (<100 ng Hg g−1). When these soils were saturated, flux was suppressed. Soil moisture evaporative stage was used to partition the parameters most important for controlling Hg flux as the soils dried. Classification and regression tree (CART) analyses showed that soil moisture was the most important parameter predicting Hg flux. Results also showed an important predictor for Hg flux was whether actual evaporation (Ea) was equal to potential evaporation (Ep) or Ea < Ep. Depending on evaporative stage, the parameters with the next highest correlation to Hg flux were light, temperature, and soil moisture evaporation rate. The presence of vegetation also influenced flux with lower Hg flux when the plants were transpiring. Results indicate for those developing models that estimate Hg flux from low Hg-containing soils, soil moisture and evaporative stage are useful tools for predicting flux.

Research paper thumbnail of Investigation of the Potential for Mercury Release from Flue Gas Desulfurization Solids Applied as an Agricultural Amendment

Journal of Environment Quality, 2014

The potential for beneficial use of flue gas desulfurization-derived gypsum (FGDG), a coal combus... more The potential for beneficial use of flue gas desulfurization-derived gypsum (FGDG), a coal combustion byproduct, as an agricultural soil amendment is currently being debated. This study investigated the hypothesis that Hg released to air from FGDG will be reduced when amended to planted and bare soils. The potential for enhanced methylmercury (MeHg) production and Hg uptake by plants in soils amended with FGDG was also investigated. Flue gas desulfurization-derived gypsum from three sources was homogenized into three soils at 4.5, 45, and 170 t ha and applied at 4.9 t ha as a thin layer to simulate tilled and no-till applications, respectively. Twenty-four-hour Hg flux was measured from unamended and FGDG-amended soils on a seasonal time step over 1 yr and after disturbing, watering, and planting. Methylmercury in soil, irrigation drainage, and total Hg in plant tissues were quantified. Results should be interpreted within the confines of the experimental setting and materials used for this study. Total Hg concentrations in soils, homogenized with FGDG, were below that considered representative of soil with background values (&amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;lt;100 ng g). Emissions from amended soils were higher initially relative to unamended soils but became similar over time. Significantly less Hg (2%) was lost to the air from FGDG-amended soils (90 g FGDG added for lowest application) than that released from the FGDG alone (30-70%) (50 g FGDG) over 1 yr. Total Hg and MeHg in irrigation drainage and total Hg concentrations measured in plants were similar for amended and unamended soils.

Research paper thumbnail of A Model for the Origin of Rhyolites From South Mountain, Pennsylvania: Implications for Rhyolites Associated With Large Igneous Provinces

…, 2010

High-silica rhyolites, ubiquitous features of continental volcanism, continue to evoke controvers... more High-silica rhyolites, ubiquitous features of continental volcanism, continue to evoke controversy as to their petrogenesis and evolution. We utilized the geochemical characteristics of late Vendian high-silica rhyolites erupted in the Catoctin Volcanic Province at South Mountain in ...

Research paper thumbnail of Distribution of chemical warfare agent, energetics, and metals in sediments at a deep water discarded military munitions site

Deep Sea Research Part II: Topical Studies in Oceanography, 2015