DOCSLIB.ORG

Stability of Dimethylmercury and Related Mercury-Containing Compounds with Respect to Selected Chemical Species Found in Aqueous Environment†

Total Page：16

File Type：pdf, Size：1020Kb

Download full-text PDF Read full-text
Stability of Dimethylmercury and Related Mercury-Containing Compounds with Respect to Selected Chemical Species Found in Aqueous Environment† CROATICA CHEMICA ACTA CCACAA, ISSN 0011-1643, e-ISSN 1334-417X Croat. Chem. Acta 86 (4) (2013) 453–462. http://dx.doi.org/10.5562/cca2314 Original Scientific Article Stability of Dimethylmercury and Related Mercury-containing Compounds † with Respect to Selected Chemical Species Found in Aqueous Environment Laimutis Bytautas Department of Chemistry, Rice University, Houston, Texas 77005, USA, Present address: Galveston College, Department of Chemistry, 4015 Avenue Q, Galveston, TX, 77550, USA. (E-mail: [email protected]) RECEIVED JUNE 23, 2013; REVISED OCTOBER 3, 2013; ACCEPTED OCTOBER 4, 2013 Abstract. Dimethylmercury (CH3−Hg−CH3) and other Hg-containing compounds can be found in atmos- pheric and aqueous environments. These substances are highly toxic and pose a serious environmental and health hazard. Therefore, the understanding of chemical processes that affect the stability of these sub- stances is of great interest. The mercury-containing compounds can be detected in atmosphere, as well as soil and aqueous environments where, in addition to water molecules, numerous ionic species are abun- dant. In this study we explore the stability of several small, Hg-containing compounds with respect to wa- + ter molecules, hydronium (H3O ) ions as well as other small molecules/ions using density functional theo- ry and wave function quantum chemistry methods. It is found that the stability of such molecules, most + notably of dimethylmercury, can be strongly affected by the presence of the hydronium H3O ions. Alt- hough the present theoretical study represents gas phase results, it implies that pH level of a solution should be a major factor in determining the degree of abundance for dimethylmercury in aqueous envi- + ronment. In particular, it is found that CH3−Hg−CH3 reacts readily with the H3O ion producing + CH3−Hg−OH2 and methane indicating that low-pH levels favor the decomposition of dimethylmercury. On the other hand, our study suggests that high-pH levels in aqueous environment would favor strongly- bound complexes of [CH3−Hg−CH3OH] species. Overall, the theoretical evidence presented in this study offers an explanation for the available experimental data concerning the stability of dimethylmercury and other mercury-containing compounds having the general structure X−Hg−Y (X,Y = + + CH3 and Cl) with respect to various ligands L (L = H2O, NH3, H3O , OH , Cl and NH4 ). (doi: 10.5562/cca2314) Keywords: dimethylmercury, ab initio quantum chemistry, potential energy surfaces, toxicology, mercu- ry-containing compounds INTRODUCTION population. A large body of experimental data document- ing effects of mercury to human health has accumulated Elemental mercury (Hg) is the only metal that is liquid over many years.8–12 In this context, theoretical studies at room temperature. This unique property evidently is are important in elucidating possible chemical mecha- related to relativistic effects.1,2 Over many years mercu- nisms involving Hg-containing species.13 It is well known ry has been classified as a transition element (see e.g. that mercury and its compounds, especially Ref. 3), however recently this classification has been methylmercury species, i.e. compounds containing 4 challenged. A recent paper by Jensen suggests that Hg CH3Hg-group, are extremely toxic to humans and other as well as Zn and Cd should not be classified as transi- living organisms.8–16 These compounds exist naturally in tion elements although some controversy still exists the environment, although human-related activities have regarding this issue.5,6 The ground state electronic con- contributed to the increased concentrations of mercury. It figuration of mercury atom is [Xe] 4f14 5d10 6s2 indicat- is understood that high affinity of the organomercurial ing that the Hg-dimer should be a weakly bound van der compounds for thiols and lipophilic characteristics are the Waals-type system in its ground state.7 critical factors in their toxicity and various living organ- Much attention has been dedicated to mercury- isms have developed unique neutralization mechanisms containing compounds containing halogens and methyl that counteract its effects. For example, bacteria devel- groups that are of practical significance to the human oped two resistance pathways which involve the cleavage † Dedicated to Professor Douglas Jay Klein on the occasion of his 70th birthday. 454 L. Bytautas, Stability of Dimethylmercury and Related Mercury-containing Compounds of Hg−C bond with a subsequent reduction of the mercu- and microbe-assisted transformations.44,45 The role ric residues to elemental mercury.15,16 The presence of played by humic acids that are abundant in aqueous methylmercurials in soil, aqueous environment and the environment has been recently discussed in Ref. 20. A atmosphere is well documented.17–27 Due to various study by Tossell44 examined the reaction energies for transport mechanisms such compounds accumulate in the formation of various CH3−Hg−L species resulting + living organisms, especially in aquatic environments. from CH3−Hg and ligands L. In particular, Tossell’s 8 44 + Methylmercury species are known to cross the blood- study indicates that (CH3−Hg−OH2 ) should be the brain barrier and are highly neurotoxic. One of the most most dominant species in natural water systems. toxic forms to humans among many mercury-containing Since methylmercury species frequently occur in chemical compounds is dimethylmercury (DMHg) with aquatic environments, one of important questions is its chemical formula CH3−Hg−CH3. DMHg is a non- investigating the stability of these compounds with polar compound and readily accumulates in fatty tis- respect to exposure of water molecules as well as hy- 8,14 + − sues. One of the important aspects in reducing the dronium (H3O ) and hydroxide (OH ) ions which, in long-term exposure of methylmecury compounds to turn are associated with pH levels of aqueous environ- human population relates to understanding of chemical ments. Of particular interest is the observed correlation and physical processes controlling its concentration. between low pH levels and instability of DMHg.32–34 Therefore, a significant volume of research has been Thus, the goal of the present theoretical study is to ex- dedicated to methylmercury, its demethylation as well as plore possible mechanisms that can contribute to the exploring other possible mechanisms involving mercu- chemical degradation of DMHg (CH3−Hg−CH3). 28–34 ry. Evidently, DMHg is the predominant methylated form of mercury in the deep ocean.23 It has been suggest- METHODOLOGY AND TECHNICAL DETAILS ed24 that the oceanic DMHg is the main source of monomethylmercury (MMHg) in the water column. The The geometry optimizations in this study were performed MMHg compound (i.e. methylmercury monocation for the following systems: H O, H O+, OH, Cl, NH +, [CH −Hg]+) plays a significant role in the aqueous envi- 2 3 4 3 CH −Hg−CH , CH −Hg−Cl, Cl−Hg−Cl, CH −Hg−OH +. ronment due to its ability to biomagnify in aquatic food 3 3 3 3 2 The ability of the Hg-containing compounds, i.e. chains leading to high toxicity levels in fish and other CH −Hg−CH , CH −Hg−Cl and Cl−Hg−Cl to form organisms. This seems to be the main pathway to the 3 3 3 complexes with the molecules of H O, H O+, OH, Cl, exposure of mercury to human population.8,12 Recent 2 3 NH + is explored by optimizing the geometries with the findings of Conaway et al.22 indicate unexpectedly high 4 inclusion of the counterpoise correction (CP) to correct concentrations of DMHg in costal surface waters. Some for the basis-set-superposition-error (BSSE).46 The basis studies35 suggest that one possible route for the degrada- set used in all the calculations is 6-31G(d,p) (spherical tion of DMHg into MMHg in aqueous environments is by harmonics) for all atoms except mercury. For the Hg evaporating of DMHg into the atmosphere and, after the atom the Stuttgart/Dresden pseudo-potential (effective- chemical transformation into MMHg, being brought back core-potential) MDF60 (see Refs. 47,48) was used to to the Ocean waters by aerosols or water vapor. An alter- treat core electrons while the MWB60 basis set was used native route for the transformation from DMHg to to treat valence electrons. The initial optimization step MMHg may involve mechanisms and chemical species uses PBE DFT-functional and the resulting optimized that can occur directly in aqueous environments. geometry is used as the starting point in the MP2 optimi- A number of theoretical studies investigating zation. After the geometry is optimized at the MP2 level chemistry of mercury-containing compounds have al- of theory, a single-point CCSD(T) calculation is per- ready been reported in the literature.36–44 For example, formed to obtain the total energy (electronic energy in- mechanisms associated with the Hg−C bond cleavage cluding nuclear repulsion). The vibrational analysis and by halogenic acids have been investigated by Barone the zero-point-energies correspond to the MP2 level of and co-workers.15 Ni et al.36 investigated possible theory. All calculations were performed using mechanisms for degrading chloromethylmercury GAUSSIAN package of ab initio programs.49 Only local (CH −Hg−Cl) and dimethylmercury (CH −Hg−CH ) 3 3 3 minima on the singlet ground-state potential energy sur- involving thiol and ammonium residues. Khalizov et face50–52 have been considered in this study. al.37 studied the reactions of Hg with halogens and dis- cussed their atmospheric implications. Shepler et al.38 have analyzed the effects of aqueous solvation on the RESULTS AND DISCUSSION thermochemistry of reactions between Hg and small halogen molecules. Furthermore, it has been proposed The strategy of this investigation is to explore possible that organic mercury-containing compounds can be complexes of the Hg-containing compounds, namely broken-down into less toxic species via photo-reduction CH3−Hg−CH3, CH3−Hg−Cl and Cl−Hg−Cl, with small Croat.
Load more

Recommended publications
  • Chemical Threat Agents Call Poison Control 24/7 for Treatment Information 1.800.222.1222 Blood Nerve Blister Pulmonary Metals Toxins
    CHEMICAL THREAT AGENTS CALL POISON CONTROL 24/7 FOR TREATMENT INFORMATION 1.800.222.1222 BLOOD NERVE BLISTER PULMONARY METALS TOXINS SYMPTOMS SYMPTOMS SYMPTOMS SYMPTOMS SYMPTOMS SYMPTOMS • Vertigo • Diarrhea, diaphoresis • Itching • Upper respiratory tract • Cough • Shock • Tachycardia • Urination • Erythema irritation • Metallic taste • Organ failure • Tachypnea • Miosis • Yellowish blisters • Rhinitis • CNS effects • Cyanosis • Bradycardia, bronchospasm • Flu-like symptoms • Coughing • Shortness of breath • Flu-like symptoms • Emesis • Delayed eye irritation • Choking • Flu-like symptoms • Nonspecific neurological • Lacrimation • Delayed pulmonary edema • Visual disturbances symptoms • Salivation, sweating INDICATIVE LAB TESTS INDICATIVE LAB TESTS INDICATIVE LAB TEST INDICATIVE LAB TESTS INDICATIVE LAB TESTS INDICATIVE LAB TESTS • Increased anion gap • Decreased cholinesterase • Thiodiglycol present in urine • Decreased pO2 • Proteinuria None Available • Metabolic acidosis • Increased anion gap • Decreased pCO2 • Renal assessment • Narrow pO2 difference • Metabolic acidosis • Arterial blood gas between arterial and venous • Chest radiography samples DEFINITIVE TEST DEFINITIVE TEST DEFINITIVE TEST DEFINITIVE TESTS DEFINITIVE TESTS • Blood cyanide levels • Urine nerve agent • Urine blister agent No definitive tests available • Blood metals panel • Urine ricinine metabolites metabolites • Urine metals panel • Urine abrine POTENTIAL AGENTS POTENTIAL AGENTS POTENTIAL AGENTS POTENTIAL AGENTS POTENTIAL AGENTS POTENTIAL AGENTS • Hydrogen Cyanide
    [Show full text]
  • Theoretical Studies of Phenylmercury Carboxylates
    TA Theoretical studies of Phenylmercury 2750 carboxylates 2010 This page is intentionally left blank Theoretical studies of Phenylmercury carboxylates Complexation Constants and Gas Phase Photo- Oxidation of Phenylmercurycarboxylates. Yizhen Tang and Claus Jørgen Nielsen CTCC, Department of Chemistry, University of Oslo This page is intentionally left blank Table of Contents Executive Summary ................................................................................................................ 1 1. Quantum chemistry studies on phenylmercurycarboxylates ..................................... 3 2. Results from quantum chemistry ................................................................................... 3 2.1 Structure of phenylmercury(II) carboxylates .............................................................. 4 2.2 Energies of complexation/dissociation ....................................................................... 9 2.3 Vertical excitation energies......................................................................................... 10 2.4 Vertical ionization energies ......................................................................................... 11 2.5 Summary of results from quantum chemistry calculations .................................... 11 3. Atmospheric fate and lifetimes of phenylmercurycarboxylates ............................... 12 3.1 Literature data............................................................................................................... 12 3.2 Estimation of the
    [Show full text]
  • Results of the Lake Michigan Mass Balance Study: Mercury Data Report
    Results of the Lake Michigan Mass Balance Study: Mercury Data Report February 2004 U.S. Environmental Protection Agency Great Lakes National Program Office (G-17J) 77 West Jackson Boulevard Chicago, IL 60604 EPA 905 R-01-012 Results of the Lake Michigan Mass Balance Study: Mercury Data Report Prepared for: US EPA Great Lakes National Program Office 77 West Jackson Boulevard Chicago, Illinois 60604 Prepared by: Harry B. McCarty, Ph.D., Ken Miller, Robert N. Brent, Ph.D., and Judy Schofield DynCorp (a CSC Company) 6101 Stevenson Avenue Alexandria, Virginia 22304 and Ronald Rossmann, Ph.D. US EPA Office of Research and Development Large Lakes Research Station 9311 Groh Road Grosse Ile, Michigan 48138 February 2004 Acknowledgments This report was prepared under the direction of Glenn Warren, Project Officer, USEPA Great Lakes National Program Office; and Louis Blume, Work Assignment Manager and Quality Assurance Officer, USEPA Great Lakes National Program Office (GLNPO). The report was prepared by Harry B. McCarty, Ken Miller, Robert N. Brent, and Judy Schofield, with DynCorp’s Science and Engineering Programs, and Ronald Rossmann, USEPA Large Lakes Research Station, with significant contributions from the LMMB Principal Investigators for mercury and Molly Middlebrook, of DynCorp. GLNPO thanks these investigators and their associates for their technical support in project development and implementation. Ronald Rossmann wishes to thank Theresa Uscinowicz for assistance with collection, preparation, and analysis of the samples; special thanks to staff of the NOAA Great Lakes Environmental Research Laboratory, University of Wisconsin-Milwaukee Great Lakes Water Institute Center for Great Lakes Studies, USEPA Great Lakes National Program, and USEPA Mid-Continent Ecology Division for collection of the samples.
    [Show full text]
  • Notes from Rao 2/13/2007 2:07:37 PM
    Environmental Assessment of Sediments and Water in Bayou Grande, Pensacola, FL. Dr. Carl J. Mohrherr Center for Environmental Diagnostics and Bioremediation University of West Florida Dr. Johan Liebens Department of Environmental Studies University of West Florida Dr. K. Ranga Rao Center for Environmental Diagnostics and Bioremediation University of West Florida June 26, 2008 FOREWORD This study is a component of the "Assessment of Environmental Pollution and Community Health in Northwest Florida" supported by a USEPA Cooperative Agreement award X-9745502 to The University of West Florida (Project Director: Dr. K. Ranga Rao). The contents of this report are solely the responsibility of the authors and do not necessarily represent the official views of the USEPA. The study was undertaken because of the increasing concern for environmental pollution and potential impacts on human health in Northwest Florida. It was designed to assess environmental impacts of toxic pollutants in Bayou Grande. Kristal Flanders managed the spatial databases for the project and drafted the maps. Her assistance has been invaluable. Chris Carlton-Franco, Brandon Jarvis, Guy Allard, and Danielle Peterson helped with the fieldwork and some laboratory procedures. Creative Commons License This work is licensed under a Creative Commons Attribution- NonCommercial- NoDerivatives 4.0 International License. i TABLE OF CONTENTS I INTRODUCTION........................................................................................................... 1 II STUDY AREA.............................................................................................................
    [Show full text]
  • Pyrophoric Materials
    Appendix A PYROPHORIC MATERIALS Pyrophoric materials react with air, or with moisture in air. Typical reactions which occur are oxidation and hydrolysis, and the heat generated by the reactions may ignite the chemical. In some cases, these reactions liberate flammable gases which makes ignition a certainty and explosion a real possibility. Examples of pyrophoric materials are shown below. (List may not be complete) (a) Pyrophoric alkyl metals and derivatives Groups Dodecacarbonyltetracobalt Silver sulphide Dialkytzincs Dodecacarbonyltriiron Sodium disulphide Diplumbanes Hexacarbonylchromium Sodium polysulphide Trialkylaluminiums Hexacarbonylmolybdenum Sodium sulphide Trialkylbismuths Hexacarbonyltungsten Tin (II) sulphide Nonacarbonyldiiron Tin (IV) sulphide Compounds Octacarbonyldicobalt Titanium (IV) sulphide Bis-dimethylstibinyl oxide Pentacarbonyliron Uranium (IV) sulphide Bis(dimethylthallium) acetylide Tetracarbonylnickel Butyllithium (e) Pyrophoric alkyl non-metals Diethylberyllium (c) Pyrophoric metals (finely divided state) Bis-(dibutylborino) acetylene Bis-dimethylarsinyl oxide Diethylcadmium Caesium Rubidium Bis-dimethylarsinyl sulphide Diethylmagnesium Calcium Sodium Bis-trimethylsilyl oxide Diethylzinc Cerium Tantalum Dibutyl-3-methyl-3-buten-1-Yniborane Diisopropylberyllium Chromium Thorium Diethoxydimethylsilane Dimethylberyllium Cobalt Titanium Diethylmethylphosphine Dimethylbismuth chloride Hafnium Uranium Ethyldimthylphosphine Dimethylcadmium Iridium Zirconium Tetraethyldiarsine Dimethylmagnesium Iron Tetramethyldiarsine
    [Show full text]
  • PROVISIONAL PEER REVIEWED TOXICITY VALUES for DIMETHYLMERCURY (CASRN 593-74-8) Derivation of Subchronic and Chronic Oral Rfds
    EPA/690/R-04/005F l Final 12-01-2004 Provisional Peer Reviewed Toxicity Values for Dimethylmercury (CASRN 593-74-8) Derivation of Subchronic and Chronic Oral RfDs Superfund Health Risk Technical Support Center National Center for Environmental Assessment Office of Research and Development U.S. Environmental Protection Agency Cincinnati, OH 45268 Acronyms and Abbreviations bw body weight cc cubic centimeters CD Caesarean Delivered CERCLA Comprehensive Environmental Response, Compensation and Liability Act of 1980 CNS central nervous system cu.m cubic meter DWEL Drinking Water Equivalent Level FEL frank-effect level FIFRA Federal Insecticide, Fungicide, and Rodenticide Act g grams GI gastrointestinal HEC human equivalent concentration Hgb hemoglobin i.m. intramuscular i.p. intraperitoneal i.v. intravenous IRIS Integrated Risk Information System IUR inhalation unit risk kg kilogram L liter LEL lowest-effect level LOAEL lowest-observed-adverse-effect level LOAEL(ADJ) LOAEL adjusted to continuous exposure duration LOAEL(HEC) LOAEL adjusted for dosimetric differences across species to a human m meter MCL maximum contaminant level MCLG maximum contaminant level goal MF modifying factor mg milligram mg/kg milligrams per kilogram mg/L milligrams per liter MRL minimal risk level i MTD maximum tolerated dose MTL median threshold limit NAAQS National Ambient Air Quality Standards NOAEL no-observed-adverse-effect level NOAEL(ADJ) NOAEL adjusted to continuous exposure duration NOAEL(HEC) NOAEL adjusted for dosimetric differences across species to a
    [Show full text]
  • Date: 1/9/2017 Question: Botulism Is an Uncommon Disorder Caused By
    6728 Old McLean Village Drive, McLean, VA 22101 Tel: 571.488.6000 Fax: 703.556.8729 www.clintox.org Date: 1/9/2017 Question: Botulism is an uncommon disorder caused by toxins produced by Clostridium botulinum. Seven subtypes of botulinum toxin exist (subtypes A, B, C, D, E, F and G). Which subtypes have been noted to cause human disease and which ones have been reported to cause infant botulism specifically in the United States? Answer: According to the cited reference “Only subtypes A, B, E and F cause disease in humans, and almost all cases of infant botulism in the United States are caused by subtypes A and B. Botulinum-like toxins E and F are produced by Clostridium baratii and Clostridium butyricum and are only rarely implicated in infant botulism” (Rosow RK and Strober JB. Infant botulism: Review and clinical update. 2015 Pediatr Neurol 52: 487-492) Date: 1/10/2017 Question: A variety of clinical forms of botulism have been recognized. These include wound botulism, food borne botulism, and infant botulism. What is the most common form of botulism reported in the United States? Answer: According to the cited reference, “In the United States, infant botulism is by far the most common form [of botulism], constituting approximately 65% of reported botulism cases per year. Outside the United States, infant botulism is less common.” (Rosow RK and Strober JB. Infant botulism: Review and clinical update. 2015 Pediatr Neurol 52: 487-492) Date: 1/11/2017 Question: Which foodborne pathogen accounts for approximately 20 percent of bacterial meningitis in individuals older than 60 years of age and has been associated with unpasteurized milk and soft cheese ingestion? Answer: According to the cited reference, “Listeria monocytogenes, a gram-positive rod, is a foodborne pathogen with a tropism for the central nervous system.
    [Show full text]
  • High Hazard Chemical Policy
    Environmental Health & Safety Policy Manual Issue Date: 2/23/2011 Policy # EHS-200.09 High Hazard Chemical Policy 1.0 PURPOSE: To minimize hazardous exposures to high hazard chemicals which include select carcinogens, reproductive/developmental toxins, chemicals that have a high degree of toxicity. 2.0 SCOPE: The procedures provide guidance to all LSUHSC personnel who work with high hazard chemicals. 3.0 REPONSIBILITIES: 3.1 Environmental Health and Safety (EH&S) shall: • Provide technical assistance with the proper handling and safe disposal of high hazard chemicals. • Maintain a list of high hazard chemicals used at LSUHSC, see Appendix A. • Conduct exposure assessments and evaluate exposure control measures as necessary. Maintain employee exposure records. • Provide emergency response for chemical spills. 3.2 Principle Investigator (PI) /Supervisor shall: • Develop and implement a laboratory specific standard operation plan for high hazard chemical use per OSHA 29CFR 1910.1450 (e)(3)(i); Occupational Exposure to Hazardous Chemicals in Laboratories. • Notify EH&S of the addition of a high hazard chemical not previously used in the laboratory. • Ensure personnel are trained on specific chemical hazards present in the lab. • Maintain Material Safety Data Sheets (MSDS) for all chemicals, either on the computer hard drive or in hard copy. • Coordinate the provision of medical examinations, exposure monitoring and recordkeeping as required. 3.3 Employees: • Complete all necessary training before performing any work. • Observe all safety
    [Show full text]
  • Method 3200: Mercury Species Fractionation and Quantification By
    METHOD 3200 MERCURY SPECIES FRACTIONATION AND QUANTIFICATION BY MICROWAVE ASSISTED EXTRACTION, SELECTIVE SOLVENT EXTRACTION AND/OR SOLID PHASE EXTRACTION SW-846 is not intended to be an analytical training manual. Therefore, method procedures are written based on the assumption that they will be performed by analysts who are formally trained in at least the basic principles of chemical analysis and in the use of the subject technology. In addition, SW-846 methods, with the exception of required method use for the analysis of method-defined parameters, are intended to be guidance methods which contain general information on how to perform an analytical procedure or technique which a laboratory can use as a basic starting point for generating its own detailed standard operating procedure (SOP), either for its own general use or for a specific project application. The performance data included in this method are for guidance purposes only, and are not intended to be and must not be used as absolute QC acceptance criteria for purposes of laboratory accreditation. 1.0 SCOPE AND APPLICATION For a summary of changes in this version from the previous version, please see Appendix A at the end of this document. 1.1 This method contains a sequential extraction and separation procedure that may be used in conjunction with a determinative method to differentiate mercury species that are present in soils and sediments. This method provides information on both total mercury and various mercury species. 1.2 The speciation of a metal, in this case mercury, involves determining the actual form of the molecules or ions that are present in the sample.
    [Show full text]
  • Chemical Terrorism Poster
    Chemical Terrorism Poster Produced by the MN Department of Health www.health.state.mn.us, the MN Laboratory System www.health.state.mn.us/mls, and The Poison Control Center www.mnpoison.org Blood Agents ▪ Symptoms Include: ▪ Vertigo ▪ Tachycardia ▪ Tachypnea ▪ Cyanosis ▪ Flu-like symptoms ▪ Nonspecific neurological symptoms ▪ Indicative Lab Tests: ▪ Increased anion gap ▪ Metabolic acidosis ▪ Narrow pO2 difference between arterial and venous samples ▪ Potential Agents: ▪ Hydrogen Cyanide ▪ Hydrogen Sulfide ▪ Carbon Monoxide ▪ Cyanogen Chloride Nerve Agents ▪ Symptoms Include: ▪ Diarrhea diaphoresis ▪ Urination ▪ Miosis ▪ Bradycardia bronchospasm, ▪ Emesis ▪ Lacrimation ▪ Salivation sweating ▪ Indicative Lab Tests: ▪ Decreased cholinesterase ▪ Increased anion gap ▪ Metabolic acidosis C H E M I C A L T E RRO RI S M P O S T E R Nerve Agents (cont.) ▪ Potential Agents: ▪ Sarin ▪ VX ▪ Tabun ▪ Soman Blister Agents ▪ Symptoms Include: ▪ Itching ▪ Erythema ▪ Yellowish blisters ▪ Flu-like symptoms ▪ Delayed eye irritation ▪ Indicative Lab Tests: ▪ Thiodyglycol present in urine ▪ Potential Agents: ▪ Sulfer Mustard ▪ Phosgene Oxime ▪ Nitrogen Mustard Choking Agents ▪ Symptoms Include: ▪ Upper respiratory tract irritation ▪ Rhinitis ▪ Coughing ▪ Choking ▪ Delayed pulmonary edema ▪ Indicative Lab Tests: ▪ Decreased pO2 ▪ Decreased pCO2 ▪ Potential Agents: ▪ Phosgene ▪ Diphosgene ▪ Chlorine Metal Agents ▪ Symptoms Include: ▪ Cough ▪ Metallic taste ▪ CNS effects ▪ Shortness of breath 2 C H E M I C A L T E RRO RI S M P O S T E R Metal Agents (cont.) ▪ Symptoms Include (cont.): ▪ Flu-like symptoms ▪ Visual disturbances ▪ Indicative Lab Tests: ▪ Proteinuria ▪ Blood mercury ▪ Urine mercury ▪ Potential Agents: ▪ Dimethylmercury ▪ Lead ▪ Copper ▪ Mercury ▪ Arsenic ▪ Copper ▪ Cadmium Call Poison Control 24/7 for Treatment Information 1-800-222-1222. Call the MDH Clinical Chemists for appropriate specimen collection, packaging and shipping information at 612-282- 3750 (After regular hours call MDH at 651-201-5414).
    [Show full text]
  • Dimethylmercury Formation Mediated by Inorganic and Organic Reduced
    www.nature.com/scientificreports OPEN Dimethylmercury Formation Mediated by Inorganic and Organic Reduced Sulfur Received: 08 March 2016 Accepted: 27 May 2016 Surfaces Published: 15 June 2016 Sofi Jonsson1,2, Nashaat M. Mazrui1 & Robert P. Mason1 Underlying formation pathways of dimethylmercury ((CH3)2Hg) in the ocean are unknown. Early work proposed reactions of inorganic Hg (HgII) with methyl cobalamin or of dissolved monomethylmercury (CH3Hg) with hydrogen sulfide as possible bacterial mediated or abiotic pathways. A significant fraction (up to 90%) of CH3Hg in natural waters is however adsorbed to reduced sulfur groups on mineral or organic surfaces. We show that binding of CH3Hg to such reactive sites facilitates the formation of (CH3)2Hg by degradation of the adsorbed CH3Hg. We demonstrate that the reaction can be mediated by different sulfide minerals, as well as by dithiols suggesting that e.g. reduced sulfur groups on mineral particles or on protein surfaces could mediate the reaction. The observed fraction of CH3Hg methylated on sulfide mineral surfaces exceeded previously observed methylation rates of CH3Hg to (CH3)2Hg in seawaters and we suggest the pathway demonstrated here could account for much of the (CH3)2Hg found in the ocean. Dimethylmercury is a volatile and highly toxic form of mercury (Hg)1. It appears to be ubiquitous in marine waters and has been found in deep hypoxic oceanic water, coastal sediments and upwelling waters and in the 2–6 mixed layer of the Arctic ocean . Reported concentrations of (CH3)2Hg in marine waters range from 0.01– 0.4 pM and (CH3)2Hg has been found to constitute a significant fraction (up to 80%) of the methylated Hg pool 1,6 (CH3Hg + (CH3)2Hg) .
    [Show full text]
  • Date: 1/9/2017 Question: Botulism Is an Uncommon Disorder Caused By
    Date: 1/9/2017 Question: Botulism is an uncommon disorder caused by toxins produced by Clostridium botulinum. Seven subtypes of botulinum toxin exist (subtypes A, B, C, D, E, F and G). Which subtypes have been noted to cause human disease and which ones have been reported to cause infant botulism specifically in the United States? Answer: According to the cited reference “Only subtypes A, B, E and F cause disease in humans, and almost all cases of infant botulism in the United States are caused by subtypes A and B. Botulinum-like toxins E and F are produced by Clostridium baratii and Clostridium butyricum and are only rarely implicated in infant botulism” (Rosow RK and Strober JB. Infant botulism: Review and clinical update. 2015 Pediatr Neurol 52: 487-492) Date: 1/10/2017 Question: A variety of clinical forms of botulism have been recognized. These include wound botulism, food borne botulism, and infant botulism. What is the most common form of botulism reported in the United States? Answer: According to the cited reference, “In the United States, infant botulism is by far the most common form [of botulism], constituting approximately 65% of reported botulism cases per year. Outside the United States, infant botulism is less common.” (Rosow RK and Strober JB. Infant botulism: Review and clinical update. 2015 Pediatr Neurol 52: 487-492) Last updated November 1, 2017 Date: 1/11/2017 Question: Which foodborne pathogen accounts for approximately 20 percent of bacterial meningitis in individuals older than 60 years of age and has been associated with unpasteurized milk and soft cheese ingestion? Answer: According to the cited reference, “Listeria monocytogenes, a gram-positive rod, is a foodborne pathogen with a tropism for the central nervous system.
    [Show full text]