Chapter 1: the Effects of Metals on Health and the Environment
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5 Heavy Metals As Endocrine-Disrupting Chemicals
5 Heavy Metals as Endocrine-Disrupting Chemicals Cheryl A. Dyer, PHD CONTENTS 1 Introduction 2 Arsenic 3 Cadmium 4 Lead 5 Mercury 6 Uranium 7 Conclusions 1. INTRODUCTION Heavy metals are present in our environment as they formed during the earth’s birth. Their increased dispersal is a function of their usefulness during our growing dependence on industrial modification and manipulation of our environment (1,2). There is no consensus chemical definition of a heavy metal. Within the periodic table, they comprise a block of all the metals in Groups 3–16 that are in periods 4 and greater. These elements acquired the name heavy metals because they all have high densities, >5 g/cm3 (2). Their role as putative endocrine-disrupting chemicals is due to their chemistry and not their density. Their popular use in our industrial world is due to their physical, chemical, or in the case of uranium, radioactive properties. Because of the reactivity of heavy metals, small or trace amounts of elements such as iron, copper, manganese, and zinc are important in biologic processes, but at higher concentrations they often are toxic. Previous studies have demonstrated that some organic molecules, predominantly those containing phenolic or ring structures, may exhibit estrogenic mimicry through actions on the estrogen receptor. These xenoestrogens typically are non-steroidal organic chemicals released into the environment through agricultural spraying, indus- trial activities, urban waste and/or consumer products that include organochlorine pesticides, polychlorinated biphenyls, bisphenol A, phthalates, alkylphenols, and parabens (1). This definition of xenoestrogens needs to be extended, as recent investi- gations have yielded the paradoxical observation that heavy metals mimic the biologic From: Endocrine-Disrupting Chemicals: From Basic Research to Clinical Practice Edited by: A. -
Lanthanides & Actinides Notes
- 1 - LANTHANIDES & ACTINIDES NOTES General Background Mnemonics Lanthanides Lanthanide Chemistry Presents No Problems Since Everyone Goes To Doctor Heyes' Excruciatingly Thorough Yearly Lectures La Ce Pr Nd Pm Sm Eu Gd Tb Dy Ho Er Tm Yb Lu Actinides Although Theorists Prefer Unusual New Proofs Able Chemists Believe Careful Experiments Find More New Laws Ac Th Pa U Np Pu Am Cm Bk Cf Es Fm Md No Lr Principal Characteristics of the Rare Earth Elements 1. Occur together in nature, in minerals, e.g. monazite (a mixed rare earth phosphate). 2. Very similar chemical properties. Found combined with non-metals largely in the 3+ oxidation state, with little tendency to variable valence. 3. Small difference in solubility / complex formation etc. of M3+ are due to size effects. Traversing the series r(M3+) steadily decreases – the lanthanide contraction. Difficult to separate and differentiate, e.g. in 1911 James performed 15000 recrystallisations to get pure Tm(BrO3)3! f-Orbitals The Effective Electron Potential: • Large angular momentum for an f-orbital (l = 3). • Large centrifugal potential tends to keep the electron away from the nucleus. o Aufbau order. • Increased Z increases Coulombic attraction to a larger extent for smaller n due to a proportionately greater change in Zeff. o Reasserts Hydrogenic order. This can be viewed empirically as due to differing penetration effects. Radial Wavefunctions Pn,l2 for 4f, 5d, 6s in Ce 4f orbitals (and the atoms in general) steadily contract across the lanthanide series. Effective electron potential for the excited states of Ba {[Xe] 6s 4f} & La {[Xe] 6s 5d 4f} show a sudden change in the broadness & depth of the 4f "inner well". -
The Periodic Electronegativity Table
The Periodic Electronegativity Table Jan C. A. Boeyens Unit for Advanced Study, University of Pretoria, South Africa Reprint requests to J. C. A. Boeyens. E-mail: [email protected] Z. Naturforsch. 2008, 63b, 199 – 209; received October 16, 2007 The origins and development of the electronegativity concept as an empirical construct are briefly examined, emphasizing the confusion that exists over the appropriate units in which to express this quantity. It is shown how to relate the most reliable of the empirical scales to the theoretical definition of electronegativity in terms of the quantum potential and ionization radius of the atomic valence state. The theory reflects not only the periodicity of the empirical scales, but also accounts for the related thermochemical data and serves as a basis for the calculation of interatomic interaction within molecules. The intuitive theory that relates electronegativity to the average of ionization energy and electron affinity is elucidated for the first time and used to estimate the electron affinities of those elements for which no experimental measurement is possible. Key words: Valence State, Quantum Potential, Ionization Radius Introduction electronegative elements used to be distinguished tra- ditionally [1]. Electronegativity, apart from being the most useful This theoretical notion, in one form or the other, has theoretical concept that guides the practising chemist, survived into the present, where, as will be shown, it is also the most bothersome to quantify from first prin- provides a precise definition of electronegativity. Elec- ciples. In historical context the concept developed in a tronegativity scales that fail to reflect the periodicity of natural way from the early distinction between antag- the L-M curve will be considered inappropriate. -
Why Do Transition Metals Have Similar Properties
Why Do Transition Metals Have Similar Properties Saturnalian Haydon never reek so round-the-clock or spruik any explanations in-flight. Cerebrovascular Elisha parries his weasands delaminating disproportionably. Dan divulgate her ohm ought, randy and grouchy. Based on the coinage metals do have low electronegativity The similar properties do transition have similar. However, the trends in these values show the usual discontinuity half way along the series. This chapter on contact, why do transition have similar properties, why does it has both of! What is the major use today cadmium also extend across the oxidizing agent in the row of exceptions to accept varying numbers exhibit so that have similar. Oh, sorry I apologize on that. The more highly charged the ion, the more electrons you have to remove and the more ionisation energy you will have to provide. Transition metals in everything from hand is more rapidly when you would you typically, why do transition have similar properties identified in ionisation energy as inner electrons can be reduced, including superconducting magnets. Here is a result, why transition metals are heated, as is still others, can ask that attack dcp molecules. Density and malleable, why do transition metals have similar properties because cobalt atom of energy for you can be determined by consuming concentrated sulfuric acid with pyrolusite. Make sure to remember your password. It has the symbol Rh. We expect to the new york: he devised the needs no difference between two electrons go now what do transition have similar properties. Also, we do not collect or ask for personally identifiable information on any of our sites. -
PVC) Products ______
CPSC Staff Report on Lead and Cadmium in Children's Polyvinyl Chloride (PVC) Products ___________________________________________ 21 November 1997 U.S. Consumer Product Safety Commission Washington, D.C. 20207 CPSC Staff Report on Lead and Cadmium in Children's Polyvinyl Chloride (PVC) Products November 1997 I. Introduction Since its inception, the U.S. Consumer Product Safety Commission (CPSC) has played a prominent role in protecting the public, especially children, from the hazards of exposure to lead and other toxic chemicals. The CPSC has a strong record of removing products from the marketplace that contain lead and result in exposures that are hazardous to children. Just this past year, Commission action resulted in manufacturers eliminating the use of lead as a stabilizer in vinyl miniblinds, stopping the production of children's jewelry containing lead, and developing and distributing guidance to state health officials and others about lead paint on public playground equipment. Several years ago, CPSC recalled crayons that contained hazardous levels of lead. The Commission is continually screening toys for the presence of lead paint and has recalled many toys that violated the Commission's lead paint standard. In 1996, CPSC found that children could be exposed to hazardous levels of lead in imported non-glossy vinyl (polyvinyl chloride, PVC) miniblinds. Following this discovery, CPSC staff collected and tested a number of children's plastic products that they believed might be repeatedly exposed to sunlight and heat such as the vinyl miniblinds. This type of exposure was shown by CPSC staff to promote the deterioration of the lead-containing PVC miniblind slats and result in the formation of lead dust on the slats' surface. -
An Alternate Graphical Representation of Periodic Table of Chemical Elements Mohd Abubakr1, Microsoft India (R&D) Pvt
An Alternate Graphical Representation of Periodic table of Chemical Elements Mohd Abubakr1, Microsoft India (R&D) Pvt. Ltd, Hyderabad, India. [email protected] Abstract Periodic table of chemical elements symbolizes an elegant graphical representation of symmetry at atomic level and provides an overview on arrangement of electrons. It started merely as tabular representation of chemical elements, later got strengthened with quantum mechanical description of atomic structure and recent studies have revealed that periodic table can be formulated using SO(4,2) SU(2) group. IUPAC, the governing body in Chemistry, doesn‟t approve any periodic table as a standard periodic table. The only specific recommendation provided by IUPAC is that the periodic table should follow the 1 to 18 group numbering. In this technical paper, we describe a new graphical representation of periodic table, referred as „Circular form of Periodic table‟. The advantages of circular form of periodic table over other representations are discussed along with a brief discussion on history of periodic tables. 1. Introduction The profoundness of inherent symmetry in nature can be seen at different depths of atomic scales. Periodic table symbolizes one such elegant symmetry existing within the atomic structure of chemical elements. This so called „symmetry‟ within the atomic structures has been widely studied from different prospects and over the last hundreds years more than 700 different graphical representations of Periodic tables have emerged [1]. Each graphical representation of chemical elements attempted to portray certain symmetries in form of columns, rows, spirals, dimensions etc. Out of all the graphical representations, the rectangular form of periodic table (also referred as Long form of periodic table or Modern periodic table) has gained wide acceptance. -
Tracing Contamination Sources in Soils with Cu and Zn Isotopic Ratios Z Fekiacova, S Cornu, S Pichat
Tracing contamination sources in soils with Cu and Zn isotopic ratios Z Fekiacova, S Cornu, S Pichat To cite this version: Z Fekiacova, S Cornu, S Pichat. Tracing contamination sources in soils with Cu and Zn isotopic ratios. Science of the Total Environment, Elsevier, 2015, 517, pp.96-105. 10.1016/j.scitotenv.2015.02.046. hal-01466186 HAL Id: hal-01466186 https://hal.archives-ouvertes.fr/hal-01466186 Submitted on 19 Mar 2019 HAL is a multi-disciplinary open access L’archive ouverte pluridisciplinaire HAL, est archive for the deposit and dissemination of sci- destinée au dépôt et à la diffusion de documents entific research documents, whether they are pub- scientifiques de niveau recherche, publiés ou non, lished or not. The documents may come from émanant des établissements d’enseignement et de teaching and research institutions in France or recherche français ou étrangers, des laboratoires abroad, or from public or private research centers. publics ou privés. Tracing contamination sources in soils with Cu and Zn isotopic ratios Fekiacova, Z.1, Cornu, S.1, Pichat, S.2 1 INRA, UR 1119 Géochimie des Sols et des Eaux, F-13100 Aix en Provence, France 2 Laboratoire de Géologie de Lyon (LGL-TPE), Ecole Normale Supérieure de Lyon, CNRS, UMR 5276, 69007 Lyon, France Abstract Copper (Cu) and zinc (Zn) are naturally present and ubiquitous in soils and are im- portant micronutrients. Human activities contribute to the input of these metals to soils in dif- ferent chemical forms, which can sometimes reach a toxic level for soil organisms and plants. Isotopic signatures could be used to trace sources of anthropogenic Cu and Zn pollution. -
Health Concerns of Heavy Metals (Pb; Cd; Hg) and Metalloids (As)
Health concerns of the heavy metals and metalloids Chris Cooksey • Toxicity - acute and chronic • Arsenic • Mercury • Lead • Cadmium Toxicity - acute and chronic Acute - LD50 Trevan, J. W., 'The error of determination of toxicity', Proc. Royal Soc., 1927, 101B, 483-514 LD50 (rat, oral) mg/kg CdS 7080 NaCl 3000 As 763 HgCl 210 NaF 52 Tl2SO4 16 NaCN 6.4 HgCl2 1 Hodge and Sterner Scale (1943) Toxicity Commonly used term LD50 (rat, oral) Rating 1 Extremely Toxic <=1 2 Highly Toxic 1 - 50 3 Moderately Toxic 50 - 500 4 Slightly Toxic 500 - 5000 5 Practically Non-toxic 5000 - 15000 6 Relatively Harmless >15000 GHS - CLP LD50 Category <=5 1 Danger 5 - 50 2 Danger 50 - 300 3 Danger 300 - 2000 4 Warning Globally Harmonised System of Classification and Labelling and Packaging of Chemicals CLP-Regulation (EC) No 1272/2008 Toxicity - acute and chronic Chronic The long-term effect of sub-lethal exposure • Toxicity - acute and chronic • Arsenic • Mercury • Lead • Cadmium Arsenic • Pesticide o Inheritance powder • Taxidermy • Herbicide o Agent Blue • Pigments • Therapeutic uses Inorganic arsenic poisoning kills by allosteric inhibition of essential metabolic enzymes, leading to death from multi- system organ failure. Arsenicosis - chronic arsenic poisoning. Arsenic LD50 rat oral mg/kg 10000 1000 LD50 100 10 1 Arsine Arsenic acid Trimethylarsine Emerald green ArsenicArsenious trisulfide oxideSodium arsenite MethanearsonicDimethylarsinic acid acid Arsenic poisoning by volatile arsenic compounds from mouldy wall paper in damp rooms • Gmelin (1839) toxic mould gas • Selmi (1874) AsH3 • Basedow (1846) cacodyl oxide • Gosio (1893) alkyl arsine • Biginelli (1893) Et2AsH • Klason (1914) Et2AsO • Challenger (1933) Me3As • McBride & Wolfe (1971) Me2AsH or is it really true ? William R. -
The Development of the Periodic Table and Its Consequences Citation: J
Firenze University Press www.fupress.com/substantia The Development of the Periodic Table and its Consequences Citation: J. Emsley (2019) The Devel- opment of the Periodic Table and its Consequences. Substantia 3(2) Suppl. 5: 15-27. doi: 10.13128/Substantia-297 John Emsley Copyright: © 2019 J. Emsley. This is Alameda Lodge, 23a Alameda Road, Ampthill, MK45 2LA, UK an open access, peer-reviewed article E-mail: [email protected] published by Firenze University Press (http://www.fupress.com/substantia) and distributed under the terms of the Abstract. Chemistry is fortunate among the sciences in having an icon that is instant- Creative Commons Attribution License, ly recognisable around the world: the periodic table. The United Nations has deemed which permits unrestricted use, distri- 2019 to be the International Year of the Periodic Table, in commemoration of the 150th bution, and reproduction in any medi- anniversary of the first paper in which it appeared. That had been written by a Russian um, provided the original author and chemist, Dmitri Mendeleev, and was published in May 1869. Since then, there have source are credited. been many versions of the table, but one format has come to be the most widely used Data Availability Statement: All rel- and is to be seen everywhere. The route to this preferred form of the table makes an evant data are within the paper and its interesting story. Supporting Information files. Keywords. Periodic table, Mendeleev, Newlands, Deming, Seaborg. Competing Interests: The Author(s) declare(s) no conflict of interest. INTRODUCTION There are hundreds of periodic tables but the one that is widely repro- duced has the approval of the International Union of Pure and Applied Chemistry (IUPAC) and is shown in Fig.1. -
The Place of Zinc, Cadmium, and Mercury in the Periodic Table
Information • Textbooks • Media • Resources The Place of Zinc, Cadmium, and Mercury in the Periodic Table William B. Jensen Department of Chemistry, University of Cincinnati, Cincinnati, OH 45221-0172; [email protected] One of the few facts that I can remember from my un- a quarter of the more recent introductory inorganic texts. In dergraduate inorganic course was my instructor’s insistence all cases, the Zn group was incorrectly labeled as being a mem- that zinc, cadmium, and mercury should be classified as main- ber of the d block or transition block. Those introductory block elements rather than as transition-block or d-block el- inorganic texts that presented some sort of systematic survey ements. Though I have always assumed that the evidence for of descriptive chemistry usually contradicted this assignment this statement was unambiguous, I have also noticed the ap- in their later discussions of the chemistry of these elements. pearance over the last decade of an increasing number of gen- On the other hand, the surveys of descriptive chemistry found eral chemistry texts, inorganic texts, and advanced inorganic in most of the general chemistry texts were so superficial that monographs that either explicitly or implicitly contradict this the existence of this inconsistency seldom became explicit. assignment. The inorganic textbook by Cotton and In light of these trends, I thought it might be of interest Wilkinson, which has served as the American standard for to summarize the evidence relating to the proper placement nearly 40 years, has always been firm in its treatment of the of the Zn group within the periodic table. -
Air Quality Comic Book
Hi, I'm Dr. Knox Our Narrator, Dr. Knox, is on his way to Today we hope to view a pollution visit a site where air pollution is likely to source and visit with environmental occur and to visit with environmental specialists from the Oklahoma personnel in action. Department of Environmental Here we are in Quality. Oklahoma trying to understand air pollution. Its a complex problem with many factors. Come join us as we learn about air Dr. Knox stops at a pollution and how to possible pollution source. control it. A Pollution Critter Questions are often asked about air pollution. Sources of air pollution come in many forms. We see many sources Just then a truck starts. in our daily lives. Some are colorless or odorless. Cough . others are more apparent, cough . If you breathe these fumes inside a building, like your garage, they could be very harmful. Dr. Knox goes to a monitoring site and waits for the Join us as specialists to arrive. we explore how pollution sources are monitored and visit At this site and with some of the others air is people involved in collected and tested the monitoring for pollutants. Lets process. find out more. Looks like no one is home. Ust then a van pulls up and two environmental specialists step out. Hi, Im Monica Hi, Im Excuse me! Aaron I want to Hi, Im Dr. Knox. ask you about how air pollution is monitored. The specialists invite us in to Youve come to show us some pollution charts. the right place. We You see, we would be glad monitor several to discuss it. -
Skillsoft Compliance Industry Insight
GUIDE 8 Things you may be Overlooking in your Workplace Safety Program 1. YOUR COMPLIANCE IDENTITY, MESSAGE, AND CULTURE “ Engaged workers are more mindful of their Your compliance identity and message are the aspects of your surroundings. They are aware of safety company that define your commitment to maintaining a safe and procedures and diligent about keeping their healthy environment. Strong safety and health programs go beyond coworkers and customers protected. 2 limited check-the-box training by having support across all levels ” of the company. It is important that employees and managers are committed to your program, and that support is consistent and Engagement begins with committed safety and health leaders who ubiquitous. By clearly defining your philosophy, beliefs, and vision, are visible, vocal, and demonstrate a climate of open communication. each person knows what is expected from them, and by making By developing an atmosphere of mutual trust and respect, while workplace safety and health a cornerstone, your employees will fostering clear communication, employees will understand the larger understand that it is part of what is expected and not optional. picture of the compliance program, feel comfortable in participation, and engage on a deeper level. Even with a strong message, it is important to integrate compliance identity as part of the overall culture. Meaning, every aspect of the business (employee, manager, and department) is aligned with the program and is dedicated to following through with it. The message WHY OPTIMIZING YOUR SAFETY needs to be carried through: hazard recognition, evaluation and PROGRAMS MATTERS control, facility design and engineering, and operational safety programs, or the program will fall short.