Tom Darrah | Ohio State University (original) (raw)
Books by Tom Darrah
*Medical Geochemistry is a new branch of Earth Science which borrows methods and approaches from ... more *Medical Geochemistry is a new branch of Earth Science which borrows methods and approaches from basic geochemical science and applies them evaluating interactions between the environment and geology and humans (e.g. bone, gastric, lung and dermatological).
*Medical Geochemistry gives comprehensive and focused approach with respect to applying geochemical techniques
The book reviews expertise on the geochemical methods used to understand the relationships that occur between human health and environment
This book includes a collection of chapters illustrating "the state of art" in applying geochemical methods to investigate the interactions between geological materials and fluids with humans. Examples include the incorporation and human health effects of inhaling lithogenic materials, the reactivity of biological fluids with geological materials, and the impact on nascent biomineral formation. Biomineralization will be investigated in terms of mineralogy, morphology, bone chemistry, and pathological significance with a focus on the health impacts of "foreign" geological/environmental trace element incorporation. One contribution will be devoted to particulate matter, the presence of metals and metalloids in the environment, and the possibility of using human hair as a biomarker between environmental/geological exposure and human bioincorporation. Other papers will be focused on the last advances on the analytical methods and instrumentational approaches to investigating the chemistry of biological fluids and tissues.
Papers by Tom Darrah
Geochimica et Cosmochimica Acta
Nature Communications, 2014
The need for accurate in vitro dosimetry remains a major obstacle to the development of cost-effe... more The need for accurate in vitro dosimetry remains a major obstacle to the development of cost-effective toxicological screening methods for engineered nanomaterials. An important key to accurate in vitro dosimetry is the characterization of sedimentation and diffusion rates of nanoparticles suspended in culture media, which largely depend upon the effective density and diameter of formed agglomerates in suspension. Here we present a rapid and inexpensive method for accurately measuring the effective density of nano-agglomerates in suspension. This novel method is based on the volume of the pellet obtained by benchtop centrifugation of nanomaterial suspensions in a packed cell volume tube, and is validated against gold-standard analytical ultracentrifugation data. This simple and cost-effective method allows nanotoxicologists to correctly model nanoparticle transport, and thus attain accurate dosimetry in cell culture systems, which will greatly advance the development of reliable and efficient methods for toxicological testing and investigation of nano-bio interactions in vitro.
Inorganic Chemistry, 2011
Studies of palladium(II) and platinum(II) binding to well-characterized proteins contribute to un... more Studies of palladium(II) and platinum(II) binding to well-characterized proteins contribute to understanding the influence of these metals in the environment and the body. The wellcharacterized apo-protein of azurin has a soft-metal binding site that may be exposed to solvent by mutation of a coordinating histidine-117 residue to glycine. Palladium(II) and platinum(II) form strong 1:1 adducts with the apo form of H117G azurin. A combination of UV-visible, CD, and ICP-MS techniques suggests that the metal binds specifically at His-46 and Cys-112 of the protein.
First measurements of magmatic gas composition and fluxes during an eruption (October 2010) of Pi... more First measurements of magmatic gas composition and fluxes during an eruption (October 2010) of Piton de la Fournaise hot spot volcano, La Reunion island 7 S. Arellano, B. Galle. New developments on remote sensing studies of volcanic gas emissions by solar infrared spectroscopy 8
Journal of Geophysical Research: Solid Earth, 2014
This article has been accepted for publication and undergone full peer review but has not been th... more This article has been accepted for publication and undergone full peer review but has not been through the copyediting, typesetting, pagination and proofreading process which may lead to differences between this version and the Version of Record. Please cite this article as
ABSTRACT Introduction: The National Children's Study (NCS) will recruit and follow a coho... more ABSTRACT Introduction: The National Children's Study (NCS) will recruit and follow a cohort of 100,000 United States children from before birth until age 21. The goal is to improve the health and well-being of children and contribute to understanding the role that many factors have on health and disease. The focus of this research is to develop methods for procuring, preserving, and processing the placenta upon delivery to evaluate the importance of examining the placenta for identifying relationships and establishing biomarkers to determine in utero genetic, environmental, and morphological contributions to childhood and adult diseases. By assessing the placenta and its architecture, vascularization, genetics, epigenetics, and environmental exposures, our understanding of prenatal contributors to child health will be realized. Methods: A pilot study was conducted to establish collection techniques, the equipment/supplies required, and analyze placental specimens acquired at different times post delivery. The field study was initiated 10/2011 based upon results of the pilot. Field sites are in Orange County, CA; Queens, NY; Montgomery County, PA; Lincoln County, MN; Yellow Medicine County, MN; Pipestone County, MN; Brookings County, SD; Duplin County, NC; Waukesha County, WI; Salt Lake County, UT; Cache County, UT. Extensive training of birth coordinators, development of a logistical support systems for collections in the field, and shipping specimens to the Placental Processing Center (PPC) for evaluation were conducted via WEB EX teleconferencing. Results: To date, approximately 100 placentae were collected/shipped to the PPC for genetic, environmental, and morphological assessments with a mean site collection time following delivery of 55+30 min (range 9min-24hr) at the widely diverse 10 county collection sites. Coupled with mother's and child's clinical histories using special coding to assure subject anonymity, novel techniques were developed for specimen collection, storage, and analysis to preserve specimen integrity for morphologic, genetic/epigenetic, and environmental exposures. Discussion: It is possible to collect, process, and analyze for morphological, genetic, and environmental analytes in placentae from multiple sites, as well as assure tissue is available for state of the art analyses of biomarkers for current and future health risk assessments.
PLoS ONE, 2013
A companion manuscript revealed that deletion of the Pseudomonas aeruginosa (Pae) PA1006 gene cau... more A companion manuscript revealed that deletion of the Pseudomonas aeruginosa (Pae) PA1006 gene caused pleiotropic defects in metabolism including a loss of all nitrate reductase activities, biofilm maturation, and virulence. Herein, several complementary approaches indicate that PA1006 protein serves as a persulfide-modified protein that is critical for molybdenum homeostasis in Pae. Mutation of a highly conserved Cys22 to Ala or Ser resulted in a loss of PA1006 activity. Yeast-two-hybrid and a green-fluorescent protein fragment complementation assay (GFP-PFCA) in Pae itself revealed that PA1006 interacts with Pae PA3667/CsdA and PA3814/IscS Cys desulfurase enzymes. Fourier transform ion cyclotron resonance mass spectrometry (FT-ICR-MS) ''top-down'' analysis of PA1006 purified from Pae revealed that conserved Cys22 is post-translationally modified in vivo in the form a persulfide. Inductively-coupled-plasma (ICP)-MS analysis of DPA1006 mutant extracts revealed that the mutant cells contain significantly reduced levels of molybdenum compared to wild-type. GFP-PFCA also revealed that PA1006 interacts with several molybdenum cofactor (MoCo) biosynthesis proteins as well as nitrate reductase maturation factor NarJ and component NarH. These data indicate that a loss of PA1006 protein's persulfide sulfur and a reduced availability of molybdenum contribute to the phenotype of a DPA1006 mutant.
Proceedings of the National Academy of Sciences, 2012
The debate surrounding the safety of shale gas development in the Appalachian Basin has generated... more The debate surrounding the safety of shale gas development in the Appalachian Basin has generated increased awareness of drinking water quality in rural communities. Concerns include the potential for migration of stray gas, metal-rich formation brines, and hydraulic fracturing and/or flowback fluids to drinking water aquifers. A critical question common to these environmental risks is the hydraulic connectivity between the shale gas formations and the overlying shallow drinking water aquifers. We present geochemical evidence from northeastern Pennsylvania showing that pathways, unrelated to recent drilling activities, exist in some locations between deep underlying formations and shallow drinking water aquifers. Integration of chemical data (Br, Cl, Na, Ba, Sr, and Li) and isotopic ratios ( 87 Sr/ 86 Sr, 2 H/H, 18 O/ 16 O, and 228 Ra/ 226 Ra) from this and previous studies in 426 shallow groundwater samples and 83 northern Appalachian brine samples suggest that mixing relationships...
Metallomics, 2009
We find anomalously high gadolinium (Gd) concentrations in the femoral head bones of patients exp... more We find anomalously high gadolinium (Gd) concentrations in the femoral head bones of patients exposed to chelated Gd, commonly used as a contrast agent for medical imaging. Gd is introduced in chelated form to protect patients from exposure to toxic free Gd(3+), a calcium antagonist which disrupts cellular processes. Recent studies suggest Gd chelates break down in vivo, and Gd accumulation in tissue is linked to medical conditions such as nephrogenic systemic fibrosis (NSF), acute kidney failure, and in some cases death. We measure Gd and other rare earth element (REE) concentrations in 35 femoral heads by solution based ICP-MS. Gd concentrations in patients with documented exposure to Gd-based contrast agents (n = 13: Gd DTPA-BMA (Omniscan) n = 6; Gd HP-DO3A (Prohance) n = 5; unknown type n = 4) are significantly higher (p < 0.001) than the control group (n = 17). We use our control group to establish the 'natural' background level of Gd in human bone (cortical 95% CI: 0.023, 0.041 nmol/g; trabecular 95% CI: 0.054, 0.107 nmol/g). A control group outlier reveals the occurrence of individuals with high concentrations of all REEs, including Gd. Because of this, we calculate Gd anomalies from the concentrations of adjacent REEs and normalize to the control group mean to isolate Gd input from contrast agents. Normalized Gd anomalies, (Gd/Gd*)(N), for exposed patients range up to >800 times the 'natural' level (95% CI: 124, 460). Our data confirm that Gd, introduced in chelated form, incorporates into bone and is retained for more than 8 years. No difference was observed in bone Gd concentrations and anomalies between patients dosed with Gd DTPA-BMA (Omniscan; n = 6) and Gd HP-DO3A (Prohance; n = 5). Osteoporotic fracture patients exposed to Gd have significantly lower Gd concentrations than osteoarthritis patients (p < 0.001). This indicates different mechanisms of…
Journal of Volcanology and Geothermal Research, 2013
Copahue volcano is part of the Caviahue-Copahue Volcanic Complex (CCVC), which is located in the ... more Copahue volcano is part of the Caviahue-Copahue Volcanic Complex (CCVC), which is located in the southwestern sector of the Caviahue volcano-tectonic depression (Argentina-Chile). This depression is a pull-apart basin accommodating stresses between the southern Liquiñe-Ofqui strike slip and the northern Copahue-Antiñir compressive fault systems, in a back-arc setting with respect to the Southern Andean Volcanic Zone. In this study, we present chemical (inorganic and organic) and isotope compositions (δ 13 C-CO 2 , δ 15 N, 3 He/ 4 He, 40 Ar/ 36 Ar, δ 13 C-CH 4 , δD-CH 4 , and δD-H 2 O and δ 18 O-H 2 O) of fumaroles and bubbling gases of thermal springs located at the foot of Copahue volcano sampled in 2006, 2007 and 2012. Helium isotope ratios, the highest observed for a Southern American volcano (R/R a up to 7.94), indicate a non-classic arc-like setting, but rather an extensional regime subdued to asthenospheric thinning. δ 13 C-CO 2 values (from − 8.8‰ to − 6.8‰ vs. V-PDB), δ 15 N values (+ 5.3‰ to + 5.5‰ vs. Air) and CO 2 / 3 He ratios (from 1.4 to 8.8 × 10 9) suggest that the magmatic source is significantly affected by contamination of subducted sediments. Gases discharged from the northern sector of the CCVC show contribution of 3 He-poor fluids likely permeating through local fault systems. Despite the clear mantle isotope signature in the CCVC gases, the acidic gas species have suffered scrubbing processes by a hydrothermal system mainly recharged by meteoric water. Gas geothermometry in the H 2 O-CO 2-CH 4-CO-H 2 system suggests that CO and H 2 re-equilibrate in a separated vapor phase at 200°-220°C. On the contrary, rock-fluid interactions controlling CO 2 , CH 4 production from Sabatier reaction and C 3 H 8 dehydrogenation seem to occur within the hydrothermal reservoir at temperatures ranging from 250°to 300°C. Fumarole gases sampled in 2006-2007 show relatively low N 2 /He and N 2 /Ar ratios and high R/R a values with respect to those measured in 2012. Such compositional and isotope variations were likely related to injection of mafic magma that likely triggered the 2000 eruption. Therefore, changes affecting the magmatic system had a delayed effect on the chemistry of the CCVC gases due to the presence of the hydrothermal reservoir. However, geochemical monitoring activities mainly focused on the behavior of inert gas compounds (N 2 and He), should be increased to investigate the mechanism at the origin of the unrest started in 2011.
Geochimica et Cosmochimica Acta, 2012
Extraterrestrial (ET) noble gases (helium and neon) in 35 sediment samples from Central Pacific c... more Extraterrestrial (ET) noble gases (helium and neon) in 35 sediment samples from Central Pacific core LL-44 GPC-3 demonstrate the variable flux of interplanetary dust particles (IDPs) and major meteorite impacts over the past 70 Ma (21-72 Ma). Spinel mineralogical and chemical compositions clearly distinguish major impact events from the continuous flux of IDPs, including the well-established Cretaceous/Tertiary (K/T) and late Eocene (E/O) impact boundaries. No spinel grains with chemical or mineralogical evidence of a distinctly ET origin were found in an extensive survey of 'background' samples (i.e. non E/O or K/T boundary) suggesting that either the carrier grains for ET noble gas occur within the Fe-Ti oxide mineral fraction observed in this study (found to include ilmenite and ulvospinel) or are too small for identification by SEM. The presence of ilmenite and ulvospinel suggest lunar regolith is a potential source for ET noble gas-rich particles. Noble gas analysis on both the EMF (extractable magnetic fraction) and the Bulk minus EMF (Bulk À EMF) show that the He and Ne compositions are consistent with partially degassed noble gas signatures of zero-age magnetic grains (Z-MAG) and stratospheric interplanetary dust particles (IDPs). Conclusive evidence for a 'planetary' (Ne-A) noble gas signature is found only in the bulk sediments at the K/T boundary, although all GPC-3 K/T fractions (Bulk, EMF, and HF Digestion) plot along a mixing line between planetary (Ne-A
Environmental Science & Technology, 2014
The rapid rise of shale gas development through horizontal drilling and high volume hydraulic fra... more The rapid rise of shale gas development through horizontal drilling and high volume hydraulic fracturing has expanded the extraction of hydrocarbon resources in the U.S. The rise of shale gas development has triggered an intense public debate regarding the potential environmental and human health effects from hydraulic fracturing. This paper provides a critical review of the potential risks that shale gas operations pose to water resources, with an emphasis on case studies mostly from the U.S. Four potential risks for water resources are identified: (1) the contamination of shallow aquifers with fugitive hydrocarbon gases (i.e., stray gas contamination), which can also potentially lead to the salinization of shallow groundwater through leaking natural gas wells and subsurface flow; (2) the contamination of surface water and shallow groundwater from spills, leaks, and/or the disposal of inadequately treated shale gas wastewater; (3) the accumulation of toxic and radioactive elements in soil or stream sediments near disposal or spill sites; and (4) the overextraction of water resources for high-volume hydraulic fracturing that could induce water shortages or conflicts with other water users, particularly in water-scarce areas. Analysis of published data (through January 2014) reveals evidence for stray gas contamination, surface water impacts in areas of intensive shale gas development, and the accumulation of radium isotopes in some disposal and spill sites. The direct contamination of shallow groundwater from hydraulic fracturing fluids and deep formation waters by hydraulic fracturing itself, however, remains controversial.
Chemical Geology, 2013
A combination of noble and major gas composition and isotope geochemistry provides a window into ... more A combination of noble and major gas composition and isotope geochemistry provides a window into the source of volatiles and the mechanisms of transport associated with a series of hot springs located near the Dallol volcano within the Danakil Depression along the Red Sea arm of the Afar triple junction. The helium isotopic composition of these gases range up to 11.9 times the atmospheric ratio (11.9 R/Ra), which suggests that the Afar plume interacts with the Afar depression across at least the 300 km transect from Tendaho-Gabo basin to Dallol within the Danakil Depression. The 4 He/ 40 Ar* of~14 in the mantle-rich end-member at Dallol indicates significant degassing prior to emplacement at Dallol either during basaltic dyke intrusions beneath the Danakil Depression or during the release and transport of fluids from a degassed subsolidus source in the upper mantle along high permeability fracture zones. The CO 2 / 3 He of the magmatic end-member is~2× higher (7.7 × 10 9) and more positive δ 13 C (CO 2) (− 2.1‰) than other archetypal plumes (e.g. Hawaii, Iceland, etc.). The Dallol composition is consistent with a hypothetical model that assumes a plume-type starting composition and experiences~92% degassing (where helium is preferentially degassed with respect to CO 2) and the addition of CO 2 from the thermal degradation of carbonate. Non-atmospheric excess N 2 with a δ 15 N (N 2) of +3.5 to +4‰ dominates the Dallol volatiles and suggests interaction between mantle fluids and Proterozoic meta-sediments. By comparing and modeling the range in atmospherically (e.g. 20 Ne, 36 Ar, 84 Kr) and mantle-derived (e.g. 4 He/ 40 Ar* and CO 2 / 3 He) components in Dallol volatiles, we propose that the coherent variations in these gases result from mixing of magmatic volatiles with extremely degassed remnant fluids present within the hydrothermal reservoir.
AAPG Bulletin, 2012
Silurian and Devonian natural gas reservoirs present within New York state represent an example o... more Silurian and Devonian natural gas reservoirs present within New York state represent an example of unconventional gas accumulations within the northern Appalachian Basin. These unconventional energy resources, previously thought to be noneconomically viable, have come into play following advances in drilling (i.e., horizontal drilling) and extraction (i.e., hydraulic fracturing) capabilities. Therefore, efforts to understand these and other domestic and global natural gas reserves have recently increased. The suspicion of fugitive mass migration issues within current Appalachian production fields has catalyzed the need to develop a greater understanding of the genetic grouping (source) and migrational history of natural gases in this area. We introduce new noble gas data in the context of published hydrocarbon carbon (C 1 ,C 2+) (d 13 C) data to explore the genesis of thermogenic gases in the Appalachian Basin. This study includes natural gases from two distinct genetic groups: group 1, Upper Devonian (Marcellus shale and Canadaway Group) gases generated in situ, characterized by early mature (D 13 C[ C1 − C2 ][d 13 C 1 − d 13 C 2 ]: <-9‰), isotopically light methane, with low (4 He) (average, 1 × 10 −3 cc/cc) elevated 4 He/ 40 Ar* and 21 Ne*/ 40 Ar* (where the asterisk denotes excess radiogenic or nucleogenic production beyond the atmospheric ratio), and a variable, atmospherically (airsaturated-water) derived noble gas component; and group 2, a migratory natural gas that emanated from Lower Ordovician
Proceedings of the National Academy of Sciences of the United States of America, Jan 30, 2014
Horizontal drilling and hydraulic fracturing have enhanced energy production but raised concerns ... more Horizontal drilling and hydraulic fracturing have enhanced energy production but raised concerns about drinking-water contamination and other environmental impacts. Identifying the sources and mechanisms of contamination can help improve the environmental and economic sustainability of shale-gas extraction. We analyzed 113 and 20 samples from drinking-water wells overlying the Marcellus and Barnett Shales, respectively, examining hydrocarbon abundance and isotopic compositions (e.g., C2H6/CH4, δ(13)C-CH4) and providing, to our knowledge, the first comprehensive analyses of noble gases and their isotopes (e.g., (4)He, (20)Ne, (36)Ar) in groundwater near shale-gas wells. We addressed two questions. (i) Are elevated levels of hydrocarbon gases in drinking-water aquifers near gas wells natural or anthropogenic? (ii) If fugitive gas contamination exists, what mechanisms cause it? Against a backdrop of naturally occurring salt- and gas-rich groundwater, we identified eight discrete cluste...
The use of general descriptive names, registered names, trademarks, service marks, etc. in this p... more The use of general descriptive names, registered names, trademarks, service marks, etc. in this publication does not imply, even in the absence of a specific statement, that such names are exempt from the relevant protective laws and regulations and therefore free for general use. While the advice and information in this book are believed to be true and accurate at the date of publication, neither the authors nor the editors nor the publisher can accept any legal responsibility for any errors or omissions that may be made. The publisher makes no warranty, express or implied, with respect to the material contained herein.
*Medical Geochemistry is a new branch of Earth Science which borrows methods and approaches from ... more *Medical Geochemistry is a new branch of Earth Science which borrows methods and approaches from basic geochemical science and applies them evaluating interactions between the environment and geology and humans (e.g. bone, gastric, lung and dermatological).
*Medical Geochemistry gives comprehensive and focused approach with respect to applying geochemical techniques
The book reviews expertise on the geochemical methods used to understand the relationships that occur between human health and environment
This book includes a collection of chapters illustrating "the state of art" in applying geochemical methods to investigate the interactions between geological materials and fluids with humans. Examples include the incorporation and human health effects of inhaling lithogenic materials, the reactivity of biological fluids with geological materials, and the impact on nascent biomineral formation. Biomineralization will be investigated in terms of mineralogy, morphology, bone chemistry, and pathological significance with a focus on the health impacts of "foreign" geological/environmental trace element incorporation. One contribution will be devoted to particulate matter, the presence of metals and metalloids in the environment, and the possibility of using human hair as a biomarker between environmental/geological exposure and human bioincorporation. Other papers will be focused on the last advances on the analytical methods and instrumentational approaches to investigating the chemistry of biological fluids and tissues.
Geochimica et Cosmochimica Acta
Nature Communications, 2014
The need for accurate in vitro dosimetry remains a major obstacle to the development of cost-effe... more The need for accurate in vitro dosimetry remains a major obstacle to the development of cost-effective toxicological screening methods for engineered nanomaterials. An important key to accurate in vitro dosimetry is the characterization of sedimentation and diffusion rates of nanoparticles suspended in culture media, which largely depend upon the effective density and diameter of formed agglomerates in suspension. Here we present a rapid and inexpensive method for accurately measuring the effective density of nano-agglomerates in suspension. This novel method is based on the volume of the pellet obtained by benchtop centrifugation of nanomaterial suspensions in a packed cell volume tube, and is validated against gold-standard analytical ultracentrifugation data. This simple and cost-effective method allows nanotoxicologists to correctly model nanoparticle transport, and thus attain accurate dosimetry in cell culture systems, which will greatly advance the development of reliable and efficient methods for toxicological testing and investigation of nano-bio interactions in vitro.
Inorganic Chemistry, 2011
Studies of palladium(II) and platinum(II) binding to well-characterized proteins contribute to un... more Studies of palladium(II) and platinum(II) binding to well-characterized proteins contribute to understanding the influence of these metals in the environment and the body. The wellcharacterized apo-protein of azurin has a soft-metal binding site that may be exposed to solvent by mutation of a coordinating histidine-117 residue to glycine. Palladium(II) and platinum(II) form strong 1:1 adducts with the apo form of H117G azurin. A combination of UV-visible, CD, and ICP-MS techniques suggests that the metal binds specifically at His-46 and Cys-112 of the protein.
First measurements of magmatic gas composition and fluxes during an eruption (October 2010) of Pi... more First measurements of magmatic gas composition and fluxes during an eruption (October 2010) of Piton de la Fournaise hot spot volcano, La Reunion island 7 S. Arellano, B. Galle. New developments on remote sensing studies of volcanic gas emissions by solar infrared spectroscopy 8
Journal of Geophysical Research: Solid Earth, 2014
This article has been accepted for publication and undergone full peer review but has not been th... more This article has been accepted for publication and undergone full peer review but has not been through the copyediting, typesetting, pagination and proofreading process which may lead to differences between this version and the Version of Record. Please cite this article as
ABSTRACT Introduction: The National Children's Study (NCS) will recruit and follow a coho... more ABSTRACT Introduction: The National Children's Study (NCS) will recruit and follow a cohort of 100,000 United States children from before birth until age 21. The goal is to improve the health and well-being of children and contribute to understanding the role that many factors have on health and disease. The focus of this research is to develop methods for procuring, preserving, and processing the placenta upon delivery to evaluate the importance of examining the placenta for identifying relationships and establishing biomarkers to determine in utero genetic, environmental, and morphological contributions to childhood and adult diseases. By assessing the placenta and its architecture, vascularization, genetics, epigenetics, and environmental exposures, our understanding of prenatal contributors to child health will be realized. Methods: A pilot study was conducted to establish collection techniques, the equipment/supplies required, and analyze placental specimens acquired at different times post delivery. The field study was initiated 10/2011 based upon results of the pilot. Field sites are in Orange County, CA; Queens, NY; Montgomery County, PA; Lincoln County, MN; Yellow Medicine County, MN; Pipestone County, MN; Brookings County, SD; Duplin County, NC; Waukesha County, WI; Salt Lake County, UT; Cache County, UT. Extensive training of birth coordinators, development of a logistical support systems for collections in the field, and shipping specimens to the Placental Processing Center (PPC) for evaluation were conducted via WEB EX teleconferencing. Results: To date, approximately 100 placentae were collected/shipped to the PPC for genetic, environmental, and morphological assessments with a mean site collection time following delivery of 55+30 min (range 9min-24hr) at the widely diverse 10 county collection sites. Coupled with mother's and child's clinical histories using special coding to assure subject anonymity, novel techniques were developed for specimen collection, storage, and analysis to preserve specimen integrity for morphologic, genetic/epigenetic, and environmental exposures. Discussion: It is possible to collect, process, and analyze for morphological, genetic, and environmental analytes in placentae from multiple sites, as well as assure tissue is available for state of the art analyses of biomarkers for current and future health risk assessments.
PLoS ONE, 2013
A companion manuscript revealed that deletion of the Pseudomonas aeruginosa (Pae) PA1006 gene cau... more A companion manuscript revealed that deletion of the Pseudomonas aeruginosa (Pae) PA1006 gene caused pleiotropic defects in metabolism including a loss of all nitrate reductase activities, biofilm maturation, and virulence. Herein, several complementary approaches indicate that PA1006 protein serves as a persulfide-modified protein that is critical for molybdenum homeostasis in Pae. Mutation of a highly conserved Cys22 to Ala or Ser resulted in a loss of PA1006 activity. Yeast-two-hybrid and a green-fluorescent protein fragment complementation assay (GFP-PFCA) in Pae itself revealed that PA1006 interacts with Pae PA3667/CsdA and PA3814/IscS Cys desulfurase enzymes. Fourier transform ion cyclotron resonance mass spectrometry (FT-ICR-MS) ''top-down'' analysis of PA1006 purified from Pae revealed that conserved Cys22 is post-translationally modified in vivo in the form a persulfide. Inductively-coupled-plasma (ICP)-MS analysis of DPA1006 mutant extracts revealed that the mutant cells contain significantly reduced levels of molybdenum compared to wild-type. GFP-PFCA also revealed that PA1006 interacts with several molybdenum cofactor (MoCo) biosynthesis proteins as well as nitrate reductase maturation factor NarJ and component NarH. These data indicate that a loss of PA1006 protein's persulfide sulfur and a reduced availability of molybdenum contribute to the phenotype of a DPA1006 mutant.
Proceedings of the National Academy of Sciences, 2012
The debate surrounding the safety of shale gas development in the Appalachian Basin has generated... more The debate surrounding the safety of shale gas development in the Appalachian Basin has generated increased awareness of drinking water quality in rural communities. Concerns include the potential for migration of stray gas, metal-rich formation brines, and hydraulic fracturing and/or flowback fluids to drinking water aquifers. A critical question common to these environmental risks is the hydraulic connectivity between the shale gas formations and the overlying shallow drinking water aquifers. We present geochemical evidence from northeastern Pennsylvania showing that pathways, unrelated to recent drilling activities, exist in some locations between deep underlying formations and shallow drinking water aquifers. Integration of chemical data (Br, Cl, Na, Ba, Sr, and Li) and isotopic ratios ( 87 Sr/ 86 Sr, 2 H/H, 18 O/ 16 O, and 228 Ra/ 226 Ra) from this and previous studies in 426 shallow groundwater samples and 83 northern Appalachian brine samples suggest that mixing relationships...
Metallomics, 2009
We find anomalously high gadolinium (Gd) concentrations in the femoral head bones of patients exp... more We find anomalously high gadolinium (Gd) concentrations in the femoral head bones of patients exposed to chelated Gd, commonly used as a contrast agent for medical imaging. Gd is introduced in chelated form to protect patients from exposure to toxic free Gd(3+), a calcium antagonist which disrupts cellular processes. Recent studies suggest Gd chelates break down in vivo, and Gd accumulation in tissue is linked to medical conditions such as nephrogenic systemic fibrosis (NSF), acute kidney failure, and in some cases death. We measure Gd and other rare earth element (REE) concentrations in 35 femoral heads by solution based ICP-MS. Gd concentrations in patients with documented exposure to Gd-based contrast agents (n = 13: Gd DTPA-BMA (Omniscan) n = 6; Gd HP-DO3A (Prohance) n = 5; unknown type n = 4) are significantly higher (p &amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;lt; 0.001) than the control group (n = 17). We use our control group to establish the &amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;#39;natural&amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;#39; background level of Gd in human bone (cortical 95% CI: 0.023, 0.041 nmol/g; trabecular 95% CI: 0.054, 0.107 nmol/g). A control group outlier reveals the occurrence of individuals with high concentrations of all REEs, including Gd. Because of this, we calculate Gd anomalies from the concentrations of adjacent REEs and normalize to the control group mean to isolate Gd input from contrast agents. Normalized Gd anomalies, (Gd/Gd*)(N), for exposed patients range up to &amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;gt;800 times the &amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;#39;natural&amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;#39; level (95% CI: 124, 460). Our data confirm that Gd, introduced in chelated form, incorporates into bone and is retained for more than 8 years. No difference was observed in bone Gd concentrations and anomalies between patients dosed with Gd DTPA-BMA (Omniscan; n = 6) and Gd HP-DO3A (Prohance; n = 5). Osteoporotic fracture patients exposed to Gd have significantly lower Gd concentrations than osteoarthritis patients (p &amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;lt; 0.001). This indicates different mechanisms of…
Journal of Volcanology and Geothermal Research, 2013
Copahue volcano is part of the Caviahue-Copahue Volcanic Complex (CCVC), which is located in the ... more Copahue volcano is part of the Caviahue-Copahue Volcanic Complex (CCVC), which is located in the southwestern sector of the Caviahue volcano-tectonic depression (Argentina-Chile). This depression is a pull-apart basin accommodating stresses between the southern Liquiñe-Ofqui strike slip and the northern Copahue-Antiñir compressive fault systems, in a back-arc setting with respect to the Southern Andean Volcanic Zone. In this study, we present chemical (inorganic and organic) and isotope compositions (δ 13 C-CO 2 , δ 15 N, 3 He/ 4 He, 40 Ar/ 36 Ar, δ 13 C-CH 4 , δD-CH 4 , and δD-H 2 O and δ 18 O-H 2 O) of fumaroles and bubbling gases of thermal springs located at the foot of Copahue volcano sampled in 2006, 2007 and 2012. Helium isotope ratios, the highest observed for a Southern American volcano (R/R a up to 7.94), indicate a non-classic arc-like setting, but rather an extensional regime subdued to asthenospheric thinning. δ 13 C-CO 2 values (from − 8.8‰ to − 6.8‰ vs. V-PDB), δ 15 N values (+ 5.3‰ to + 5.5‰ vs. Air) and CO 2 / 3 He ratios (from 1.4 to 8.8 × 10 9) suggest that the magmatic source is significantly affected by contamination of subducted sediments. Gases discharged from the northern sector of the CCVC show contribution of 3 He-poor fluids likely permeating through local fault systems. Despite the clear mantle isotope signature in the CCVC gases, the acidic gas species have suffered scrubbing processes by a hydrothermal system mainly recharged by meteoric water. Gas geothermometry in the H 2 O-CO 2-CH 4-CO-H 2 system suggests that CO and H 2 re-equilibrate in a separated vapor phase at 200°-220°C. On the contrary, rock-fluid interactions controlling CO 2 , CH 4 production from Sabatier reaction and C 3 H 8 dehydrogenation seem to occur within the hydrothermal reservoir at temperatures ranging from 250°to 300°C. Fumarole gases sampled in 2006-2007 show relatively low N 2 /He and N 2 /Ar ratios and high R/R a values with respect to those measured in 2012. Such compositional and isotope variations were likely related to injection of mafic magma that likely triggered the 2000 eruption. Therefore, changes affecting the magmatic system had a delayed effect on the chemistry of the CCVC gases due to the presence of the hydrothermal reservoir. However, geochemical monitoring activities mainly focused on the behavior of inert gas compounds (N 2 and He), should be increased to investigate the mechanism at the origin of the unrest started in 2011.
Geochimica et Cosmochimica Acta, 2012
Extraterrestrial (ET) noble gases (helium and neon) in 35 sediment samples from Central Pacific c... more Extraterrestrial (ET) noble gases (helium and neon) in 35 sediment samples from Central Pacific core LL-44 GPC-3 demonstrate the variable flux of interplanetary dust particles (IDPs) and major meteorite impacts over the past 70 Ma (21-72 Ma). Spinel mineralogical and chemical compositions clearly distinguish major impact events from the continuous flux of IDPs, including the well-established Cretaceous/Tertiary (K/T) and late Eocene (E/O) impact boundaries. No spinel grains with chemical or mineralogical evidence of a distinctly ET origin were found in an extensive survey of 'background' samples (i.e. non E/O or K/T boundary) suggesting that either the carrier grains for ET noble gas occur within the Fe-Ti oxide mineral fraction observed in this study (found to include ilmenite and ulvospinel) or are too small for identification by SEM. The presence of ilmenite and ulvospinel suggest lunar regolith is a potential source for ET noble gas-rich particles. Noble gas analysis on both the EMF (extractable magnetic fraction) and the Bulk minus EMF (Bulk À EMF) show that the He and Ne compositions are consistent with partially degassed noble gas signatures of zero-age magnetic grains (Z-MAG) and stratospheric interplanetary dust particles (IDPs). Conclusive evidence for a 'planetary' (Ne-A) noble gas signature is found only in the bulk sediments at the K/T boundary, although all GPC-3 K/T fractions (Bulk, EMF, and HF Digestion) plot along a mixing line between planetary (Ne-A
Environmental Science & Technology, 2014
The rapid rise of shale gas development through horizontal drilling and high volume hydraulic fra... more The rapid rise of shale gas development through horizontal drilling and high volume hydraulic fracturing has expanded the extraction of hydrocarbon resources in the U.S. The rise of shale gas development has triggered an intense public debate regarding the potential environmental and human health effects from hydraulic fracturing. This paper provides a critical review of the potential risks that shale gas operations pose to water resources, with an emphasis on case studies mostly from the U.S. Four potential risks for water resources are identified: (1) the contamination of shallow aquifers with fugitive hydrocarbon gases (i.e., stray gas contamination), which can also potentially lead to the salinization of shallow groundwater through leaking natural gas wells and subsurface flow; (2) the contamination of surface water and shallow groundwater from spills, leaks, and/or the disposal of inadequately treated shale gas wastewater; (3) the accumulation of toxic and radioactive elements in soil or stream sediments near disposal or spill sites; and (4) the overextraction of water resources for high-volume hydraulic fracturing that could induce water shortages or conflicts with other water users, particularly in water-scarce areas. Analysis of published data (through January 2014) reveals evidence for stray gas contamination, surface water impacts in areas of intensive shale gas development, and the accumulation of radium isotopes in some disposal and spill sites. The direct contamination of shallow groundwater from hydraulic fracturing fluids and deep formation waters by hydraulic fracturing itself, however, remains controversial.
Chemical Geology, 2013
A combination of noble and major gas composition and isotope geochemistry provides a window into ... more A combination of noble and major gas composition and isotope geochemistry provides a window into the source of volatiles and the mechanisms of transport associated with a series of hot springs located near the Dallol volcano within the Danakil Depression along the Red Sea arm of the Afar triple junction. The helium isotopic composition of these gases range up to 11.9 times the atmospheric ratio (11.9 R/Ra), which suggests that the Afar plume interacts with the Afar depression across at least the 300 km transect from Tendaho-Gabo basin to Dallol within the Danakil Depression. The 4 He/ 40 Ar* of~14 in the mantle-rich end-member at Dallol indicates significant degassing prior to emplacement at Dallol either during basaltic dyke intrusions beneath the Danakil Depression or during the release and transport of fluids from a degassed subsolidus source in the upper mantle along high permeability fracture zones. The CO 2 / 3 He of the magmatic end-member is~2× higher (7.7 × 10 9) and more positive δ 13 C (CO 2) (− 2.1‰) than other archetypal plumes (e.g. Hawaii, Iceland, etc.). The Dallol composition is consistent with a hypothetical model that assumes a plume-type starting composition and experiences~92% degassing (where helium is preferentially degassed with respect to CO 2) and the addition of CO 2 from the thermal degradation of carbonate. Non-atmospheric excess N 2 with a δ 15 N (N 2) of +3.5 to +4‰ dominates the Dallol volatiles and suggests interaction between mantle fluids and Proterozoic meta-sediments. By comparing and modeling the range in atmospherically (e.g. 20 Ne, 36 Ar, 84 Kr) and mantle-derived (e.g. 4 He/ 40 Ar* and CO 2 / 3 He) components in Dallol volatiles, we propose that the coherent variations in these gases result from mixing of magmatic volatiles with extremely degassed remnant fluids present within the hydrothermal reservoir.
AAPG Bulletin, 2012
Silurian and Devonian natural gas reservoirs present within New York state represent an example o... more Silurian and Devonian natural gas reservoirs present within New York state represent an example of unconventional gas accumulations within the northern Appalachian Basin. These unconventional energy resources, previously thought to be noneconomically viable, have come into play following advances in drilling (i.e., horizontal drilling) and extraction (i.e., hydraulic fracturing) capabilities. Therefore, efforts to understand these and other domestic and global natural gas reserves have recently increased. The suspicion of fugitive mass migration issues within current Appalachian production fields has catalyzed the need to develop a greater understanding of the genetic grouping (source) and migrational history of natural gases in this area. We introduce new noble gas data in the context of published hydrocarbon carbon (C 1 ,C 2+) (d 13 C) data to explore the genesis of thermogenic gases in the Appalachian Basin. This study includes natural gases from two distinct genetic groups: group 1, Upper Devonian (Marcellus shale and Canadaway Group) gases generated in situ, characterized by early mature (D 13 C[ C1 − C2 ][d 13 C 1 − d 13 C 2 ]: <-9‰), isotopically light methane, with low (4 He) (average, 1 × 10 −3 cc/cc) elevated 4 He/ 40 Ar* and 21 Ne*/ 40 Ar* (where the asterisk denotes excess radiogenic or nucleogenic production beyond the atmospheric ratio), and a variable, atmospherically (airsaturated-water) derived noble gas component; and group 2, a migratory natural gas that emanated from Lower Ordovician
Proceedings of the National Academy of Sciences of the United States of America, Jan 30, 2014
Horizontal drilling and hydraulic fracturing have enhanced energy production but raised concerns ... more Horizontal drilling and hydraulic fracturing have enhanced energy production but raised concerns about drinking-water contamination and other environmental impacts. Identifying the sources and mechanisms of contamination can help improve the environmental and economic sustainability of shale-gas extraction. We analyzed 113 and 20 samples from drinking-water wells overlying the Marcellus and Barnett Shales, respectively, examining hydrocarbon abundance and isotopic compositions (e.g., C2H6/CH4, δ(13)C-CH4) and providing, to our knowledge, the first comprehensive analyses of noble gases and their isotopes (e.g., (4)He, (20)Ne, (36)Ar) in groundwater near shale-gas wells. We addressed two questions. (i) Are elevated levels of hydrocarbon gases in drinking-water aquifers near gas wells natural or anthropogenic? (ii) If fugitive gas contamination exists, what mechanisms cause it? Against a backdrop of naturally occurring salt- and gas-rich groundwater, we identified eight discrete cluste...
The use of general descriptive names, registered names, trademarks, service marks, etc. in this p... more The use of general descriptive names, registered names, trademarks, service marks, etc. in this publication does not imply, even in the absence of a specific statement, that such names are exempt from the relevant protective laws and regulations and therefore free for general use. While the advice and information in this book are believed to be true and accurate at the date of publication, neither the authors nor the editors nor the publisher can accept any legal responsibility for any errors or omissions that may be made. The publisher makes no warranty, express or implied, with respect to the material contained herein.
Proceedings of the National Academy of Sciences, 2012